Dipeptidyl Peptidase IV and Its Inhibitors - ACS Publications

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Dipeptidyl peptidase IV and its inhibitors: therapeutics for type 2 diabetes and what else ? Lucienne Juillerat-Jeanneret J. Med. Chem., Just Accepted Manuscript • DOI: 10.1021/jm400658e • Publication Date (Web): 07 Oct 2013 Downloaded from http://pubs.acs.org on October 13, 2013

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Journal of Medicinal Chemistry 1

Dipeptidyl peptidase IV and its inhibitors: therapeutics for type 2 diabetes and what else ?

L. Juillerat-Jeanneret*

University Institute of Pathology, CHUV-UNIL, Lausanne, Switzerland

ACS Paragon Plus Environment

Journal of Medicinal Chemistry

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Abstract The proline-specific dipeptidyl aminopeptidase IV (DPP IV, DPP-4, CD26), widely expressed in mammalians, releases X-Pro/Ala dipeptides from the N-terminus of peptides. DPP IV is responsible of the degradation of the incretin peptide hormones regulating blood glucose levels. Several families of DPP IV inhibitors have been synthesized and evaluated. Their positive effects on the degradation of the incretins and the control of blood glucose levels have been demonstrated in biological models and in clinical trials. Presently, several DPP IV inhibitors, the “gliptins”, are approved for type 2 diabetes or are under clinical evaluation. However, the gliptins may also be of therapeutic interest for other diseases beyond the inhibition of incretin degradation. In this Perspective, the biological functions and potential substrates of DPP IV enzymes are reviewed and the characteristics of the DPP IV inhibitors are discussed, in view of type 2 diabetes and further therapeutic interest.

Key words: dipeptidyl peptidase / prolyl-specific / DPP IV / DPP-4 / inhibitors / therapy / gliptins


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Introduction Proteolytic post-translational modification of peptides by peptidases, either secreted, cell surface or intracellular enzymes, is a major regulatory event for biologically active peptides. Peptidases may either activate, or inactivate, or modulate the activities of biological peptides. Therefore, peptidase activities are major targets for the development of drugs aimed at treating human disorders, such as cancer, degenerative, immune/inflammatory or metabolic disorders; and selective inhibitors for peptidases are in clinical use or are under development. This includes the development of inhibitors for a peptidase which has been involved in the pathogenesis of the metabolic disease type 2 diabetes (T2D), the prolyl-specific dipeptidyl aminopeptidase IV (DPP IV, DPP-4, CD26). Many biologically active peptides are protected from general proteolytic degradation by evolutionary conserved prolyl (Pro) residues which induce conformational constraints in peptide hormones.1 Only a few Pro-specific proteases have been described.2-10 However, presently, inhibitors for only one prolyl-specific peptidase, the DPP IV peptidase, are in clinical use and under further clinical development, for the control of T2D. T2D is a metabolic disease linked to aging, hypertension and obesity. T2D complications involve dysfunction of the ocular, the nervous, the renal and the cardiovascular systems. T2D arises as a consequence of resistance to insulin action. In response to food intake and an increase in blood glucose, the incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are released by the gut. These hormones bind to their respective receptors, potentiating insulin synthesis and secretion, inhibiting glucagon release and reducing glucose production by the liver. Altogether in a normal situation these effects result in a decrease in blood glucose. In T2D, following secretion these incretin hormones are rapidly degraded into inactive peptides by the enzyme DPP IV, present in the blood and ubiquitously expressed at the



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surface of endothelial and epithelial cells. The hydrolysis of incretins by DPP IV inhibits the normal functions of these hormones. Evidence in vivo in experimental animal models and in initial clinical trials has demonstrated that DPP IV inhibitors have therapeutic potential in the long-term chronic treatment of T2D, delaying disease progression and decreasing the circulating levels of glycated hemoglobin (HbA1c), which is used as a reporter for long-term hyperglycemia. As stated above, DPP IV catalyzes the cleavage of GLP-1(7-36) to GLP-1(9-36), and of GIP(142) to GIP(3-42), respectively. The unhydrolyzed hormones mediate glucose-stimulated insulin secretion, while the truncated versions are antagonists of the binding of the hormones to their receptors. DPP IV is hence a relevant target for the therapeutic control of T2D. The main player of this pathway, GLP-1 (GIP being of lower relevance than GLP-1 in the context of T2D), is a gastrointestinal hormone released by the intestine, but which targets the pancreas where it enhances glucose-induced insulin secretion, and also induces satiety. As GLP-1 is rapidly inactivated by DPP IV, inhibitors of DPP IV increase the circulating levels of the endogenous bioactive GLP-1.11 Orally-active small molecule agonists of GLP-1-receptors, GLP-1 infusion or DPP IV-resistant GLP-1 analogs represent other possibilities than DPP IV inhibitors to treat T2D. However, parenteral administration of these peptides is necessary for such therapeutic approaches. Presently, standard pharmacological antidiabetic treatments include sulfonylureas (tolbutamide, glyburide, etc), glinides (repaglinide, nateglinide), biguanides (metformin), glitazones (rosigliztazone, pioglitazone), α-glucosidase inhibitors (miglitol, acarbose). These agents have important side-effects, like weight gain, edema, digestive problems, and importantly, hypoglycemic episodes; such side-effects are not shared by the DPP IV inhibitors, collectively called the “gliptins”, and by metformin. In this Perspective, I will concentrate on the


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development of inhibitors of DPP IV, initially developed for T2D, which are now in clinical use and on the evaluation of some of the new inhibitors presently under experimental and clinical development. I will also review some of the other potential biological pathways, other than the incretin system, which may be modified by the inhibitors of DPP IV.

The proteic and enzymatic characteristics of the DPP IV amino-dipeptidase Dipeptidyl aminopeptidase IV (DPP IV/DPP-4/CD26, EC 3.4.14.5.) is a dimeric type II integral membrane glycoprotein of 766 amino acids, able to release X-Pro or X-Ala dipeptides from the free N-terminal sequence of peptides. The protein consists in a small cytoplasmic domain, a transmembrane domain and a large extracellular domain containing the active site. The DPP IV gene is constituted of 26 exons, the promoter contains no TATA or CAAT box, but NFkB, AP2 and Sp1 binding sites, and is GC-rich, suggesting potential regulation of its expression by promoter methylation. In support of this hypothesis, we have previously shown that detection of DPP IV mRNA does not always correlate with protein expression and enzymatic activity.12 The 3D-structure of DPP IV (X-ray crystal structure) and the crystal structure of DPP IV bound to its inhibitors have been determined.13-17 The enzyme is a homodimer (the crystallized porcine enzyme may be a symmetric tetramer, depending on the gylcosylation of the β-propeller13). Each subunit comprises a C-terminal α/β-hydrolase domain encompassing the enzymatic active site, and a N-terminal eight-bladed β-propeller domain.13,15,18 A large cavity located between the domains contains the inhibitor binding pocket (Glu205, Glu206 and Arg125) provided by both subunits. The free N-terminal-amine of the substrate binds to Glu205 and Arg125 stabilizes the amide carbonyl. The binding pocket for the Pro residue of the substrate is formed by hydrophobic aromatic amino acids from the α/β hydrolase domain, with no space for large



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substituents at that position. The information obtained for the DPP IV family of peptidases suggests that the substrate accesses the buried active site through the β-propeller, and that the products leave through a different exit site. The Gly-Trp-Ser-Tyr-Gly sequence around the active Ser and the organization of the catalytic triad is conserved in the DPP IV family members.2-6 The active site Ser (Ser630) can form an imidate with nitrile-bearing inhibitors (cf below). From these observations, several families of inhibitors have been designed, synthesized and their inhibitory potential evaluated on purified enzymes.19-24 Surprisingly and interestingly, a wide variety of structures demonstrated inhibitory potential for DPP IV activity, suggesting low stringency, but also a wide range of binding modes for inhibitors. As a consequence, a huge number of different chemical structures and analogs have been designed and developed as DPP IV inhibitors. Their effects have been determined using purified enzymes, biological models and clinical trials, suggesting therapeutically interesting properties (cf below). DPP IV belongs to a family of prolyl-specific proteases which contains several closely related members: DPP-2/QPP, DPP-8, DPP-9, FAP-α and POP/PREP (for a more detailed review, 31,32). Most prolyl-specific peptidases belong to the class of serine proteases, and may be secreted, cellmembrane inserted or intracellular proteins. However, the observation that these proteases are ubiquitously expressed in various cellular locations, and with comparable overlapping enzymatic activities, is challenging for the development of selective inhibitors and also for defining the biological target(s) of these inhibitors. The information previously obtained suggests that inhibitor selectivity is of utmost importance to avoid side-effects and toxicity. DPP IV and FAPα (fibroblast activation protein-α/seprase) share the highest sequence homology. Therefore, the biological effects of DPP IV inhibitors attributed to DPP IV may be related to other members of the family. The serine protease enzymes of the DPP IV family exhibit similarities in their


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catalytic behavior: preference for Pro in P1-position, similar rate constants and catalytic mechanisms different from other serine proteases of the trypsin and subtilisin families. Nearly all peptides bearing an X-P- or X-A-sequence (X is variable) are potential substrates for DPP IV, including cytokines, chemokines, and growth factors. DPP IV-mediated limited proteolysis of these peptides results either in their activation, or modulation of activity, or initiation of degradation.4,25,26 It has been postulated that DPP IV inhibitors may prolong the half-life of the non-hydrolyzed forms of these peptides, thus enhancing their bioactivity, or on the contrary may block their activation. However, as stated above, the therapeutic efficacy of DPP IV inhibitors has been mainly demonstrated for the peptides involved in the pathogenesis of T2D.4,25,27-30 DPP IV has several different functions: i) as already stated, as a regulatory protease, involved in the digestion of Pro/Ala-containing oligopeptides, nutrients, and in the absorption of their fragments; ii) as a binding protein, in particular for collagens I, III via the DPP IV Cys-rich domain, independently of its enzymatic activity; iii) as a receptor associated with CD45 and adenosine deaminase (ADA); and iv) as a costimulatory molecule for lymphocytes, DPP IV being known as CD26 in the immune context. DPP IV is widely expressed in epithelial and nonepithelial tissues, the highest expression being observed in the kidney and the colon, and can be released from the cell membrane into the blood. Several families of DPP IV inhibitors have been synthesized, with increased selectivity for DPP IV versus the other members of the family. However, only DPP IV inhibitors will be considered in this Perspective. They will be reviewed first as anti-diabetic drugs able to protect the incretin peptide hormones from rapid degradation (cf below), then assessing other possible substrates and functions for this enzyme and its inhibitors. It has also to be emphasized that other proteolytic enzymes, and their associated inhibitors, are involved in the degradation of GLP-1, in addition to



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DPP IV, which may have therapeutic importance,33 and may have to be considered in the future for development of therapeutics.

Initial development of DPP IV inhibitors in clinical use for type 2 diabetes (T2D) Peptidomimetics were the first class of DPP IV inhibitors designed and evaluated. As they were associated with poor biological stability, non-peptidomimetic inhibitors were then developed. Covalent and non-covalent inhibitors of DPP IV have been designed, developed and evaluated in vitro, in vivo and in clinical trials. Several synthetic routes were explored during these initial developments,34-59 which will not be described in depth in this Perspective. We and many others have recently reviewed these initial developments.28,32,60,61 Thus only the most relevant information, and in particular the information concerning the molecules which were evaluated in humans, will be provided here. A detailed model of the binding of non-peptidomimetic inhibitors to DPP IV is provided in an extensive, detailed and excellent review61 of the development of DPP IV inhibitors. The readers interested in obtaining extensive information on the SAR development of DPP IV inhibitors and their modeling into DPP IV are are referred to this review. This model and all other models propose that a primary amine, an aromatic ring and a variable substituent are necessary on the core scaffold. The C-terminus of the enzyme consists of the catalytic triad Ser630, Asp708 (Asn710), His740 and the hydrophobic S1 pocket (Tyr631, Val656, Trp659, Tyr662, Tyr666, Val711). The S2 pocket (Arg125, Glu205, Glu206, Phe357, Ser209, Arg358) is involved both in the key salt bridge interactions of cationic groups with Glu205 and Glu206 and the main binding site involving the residues Ser209, Phe357, Arg358, allowing inhibitor selectivity for DPP IV over DPP-8 and DPP-9. In the schematic representation of the binding of DPP IV inhibitors to the enzyme shown in Schema 1, the example represents a


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covalent theoretical inhibitor and only the minimal amino acids which have been most frequently involved in the binding. Due to the large diversity of the chemical structures able to inhibit DPP IV, each inhibitor will display a slightly or largely different mode of binding than this theoretical covalent inhibitor, involving other amino acids in the S2 pocket binding site and S1 selectivity pocket of the enzyme.

Scheme 1: amino acids involved in the binding of inhibitors to DPP IV.

Different core scaffolds and analogs have been explored: xanthine analogs, quinazolinone and pyrimidone analogs, β-homophenylalanine analogs, (constrained) phenethylamine analogs, arylmethylamine analogs, aminobenzo[α]quinolizine analogs or sulphostin analogs. Their modes of binding to DPP IV have been proposed (Scheme 2).61 The impact of specific substituents of the different scaffolds on the inhibitory activity, selectivity and side-effects was also analyzed in detail in this extensive review. The most relevant information from SAR studies can be summarized as follows. For xanthine analogs, an aminopiperidine or piperazine group was necessary for inhibition. Substituents of the N-7 position occupying the S1 pocket allowed control of selectivity. Optimization of xanthine scaffolds afforded quinazolinone and pyrimidinone analogs. For this series, a 2-cyanobenzyl group occupying the S1 pocket interacted with Arg125, while the R-aminopiperidine group formed a salt bridge. A phenyl ring on the quinazolinone scaffold improved selectivity, while pyrimidinone analogs displayed better pharmacokinetic profiles. For β-homophenylalanine scaffolds, a trifluorophenyl group was optimal to occupy the S1 pocket. The chirality of the amino group was important for inhibition and the physicochemical characteristics of the substituents of the amide carbonyl were important



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for occupancy of the S2 pocket. Starting from β-homophenylalanine scaffolds, constrained phenethylamine analogs were prepared and SAR studies demonstrated that a trifluorobenzyl group on the ring was optimal to fill the S1 pocket, while substituents on the 4-position of the central ring allowed occupying the S2 pocket. Arylmethylamine analogs need a central rigid aromatic core able to form a π-π interaction with Arg125 and another substituent able to form a salt bridge. The filling of the hydrophobic S1 pocket with a substituted phenyl ring is necessary, while the filling of the S2 pocket is less strictly defined. The optimization of aminobenzo[α]quinolizine mainly focused on the substituents occupying the S1 pocket. Finally, the analogs of sulphostin (3(S)-amino-1-((R)-amino(sulfoamino)phosphinyl)-2-piperidone, a DPP IV inhibitor isolated from culture broth of Streptomyces sp., structure not disclosed) displayed the best potency if the central lactam ring was five-membered with an S C-3 configuration. More recently new possibilities have also been explored. For example, a carboxyl group-based DPP IV inhibitor able demonstrated an ionic interaction with Arg12562 and good pharmacodynamic and pharmacokinetic properties.

Scheme 2: binding modes of the different scaffold-based analogs in the DPP IV enzyme [adapted from61].

The first inhibitors of DPP IV available were the tripeptides Diprotin A (Ile–Pro-Ile) and Diprotin B (Val-Pro-Leu), which likely act as competitive substrates. The first classes of DPP IV inhibitors evaluated were substrate analogs bearing a pyrrolidine ring. The first biological validation of DPP IV as a therapeutic target was provided by 1 (Val-Pyr), which was also evaluated in an X-ray crystal structure of DPP IV.15 The results then allowed for the synthesis of new pyrrolidine analogs with optimized properties by several academic and industrial groups.


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Alpha-aminoacylpyrrolidine derivatives have been exploited to synthesize reversible DPP IV inhibitors. Considering the selectivity of DPP IV for Pro at the P1 position, DPP IV inhibitors having 5-membered heterocyclic rings mimicking proline were designed. However, it has to be emphasized that GLP-1, the initial target of DPP IV inhibition, has an Ala at that position. A free N-terminal amino group is mandatory for substrate binding to DPP IV, whereas any amino acid is permitted at this position, branched amino acids being preferred. The requirement of DPP IV for a free N-terminal amine allows selectivity over prolyl-endopeptidases, and the accommodation of pyrrolidine at the cleavage site allows for selectivity over other exoamino(di)peptidases. Potency depends on the presence of an electrophile at the 2-position of the pyrrolidine ring, able to form an adduct with the Ser (Ser630) of the enzyme active site. Thus small molecules bearing electrophiles able to interact with the catalytic serine have been mostly designed. Product-like inhibitors lacking an electrophile are more stable in biological media, but generally less potent. One example is 2 (P32/98) (Ki=126 nM), which has been evaluated in early phase clinical trials only.

Scheme 3: DPP IV inhibitors evaluated in initial clinical trials.

Irreversible inhibitors have also been identified. In light of the substrate specificity of DPP IV, aminoacylpyrrolidine derivatives bearing an electrophile at the 2-position of the ring have been initially explored to increase potency. Then, compounds targeting the active site serine and containing diphenylphosphonate esters or O-acylhydroxamic acids were developed as irreversible inhibitors of DPP IV, while the presence of a boronic acid or nitrile moieties provides slowly reversible potent covalent inhibitors. The most explored covalent inhibitors are



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those containing a nitrile at that position. The nitrile, boronic acid and diphenylphosphonate electrophilic groups can lead to biological stability issues and unfavorable pharmacokinetic and pharmacodynamic profiles. However, this is not always true, since for example, 5 (vildagliptin/LAF237),42 structure shown in Table 1, 5, now approved for clinical use in Europe), which is a nitrile-based DPP IV inhibitor, does not have all of the biological issues cited above. Thus, the development of 3 (NVP-DPP728) has been discontinued in favor of 5, which has a better pharmacokinetic profile. The replacement of the pyrrolidine with heterocycles, thiazolidine, piperidine, homopiperidine, oxalidine, has also been explored.28,34,35 Consistent with the substrate specificity at the P2, a wide range of side chains are tolerated, but at that position a free N-terminal is required. N-substituted glycine derivatives, including the bulky adamantyl group, have also been explored as DPP IV inhibitors, resulting in compounds 3 (IC50=22 nM) and 5 (IC50=3.5 nM). Structures devoid of peptide-like character, like xanthine, isoquinoline and isoquinolinone derivatives are also potentially interesting scaffolds which were explored. Selectivity over other exopeptidases of the DPP IV family, with very similar activity, active site and kinetic properties, was more difficult to achieve. The biological functions of most of the enzymes of the DPP IV family may recover the enzymatic functions of DPP IV. Therefore, selectivity is an important consideration in designing inhibitors, in particular selectivity toward FAP-α/seprase was the most difficult to achieve. Inhibitors without an electrophilic group were also developed but at the price of a loss of selectivity for DPP IV versus the other dipeptidyl peptidases of the family, DPP-2, DPP-8 and DPP-9.63 Early inhibitors of DPP IV (3, 5 or 4 (MK-0431/sitagliptin))29 were therefore evaluated in preclinical or clinical trials for the potentiation of the effects of GLP-1 for the treatment of T2D. They were safe and well-tolerated, and dose-dependently inhibited DPP IV activity, decreasing


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the circulating levels of glucose and of glycated hemoglobin (HbAc1), a marker for chronic hyperglycemia in diabetic patients, with few side-effects.29,64 As inhibition of off-target enzymes has been associated with toxicity, selectivity was important, and the initial trials have demonstrated safety of these drugs. The clinical evaluation of these drugs has demonstrated a large tolerability, safety, and efficacy. Adverse effects of DPP IV inhibitors, including nasopharyngitis, headache, nausea, hypersensitivity, skin reactions and pancreatitis have been observed, but with the exception of pancreatitis, they were minor problems. Importantly, compared to the earlier treatments for T2D, they displayed the advantage of not inducing weight gain, edema and hypoglycemia. A non-substrate-like non-covalent inhibitor bearing an aromatic ring instead of a proline mimetic led to the discovery of compound 4, the first DPP IV inhibitor that was approved by the FDA for the treatment of T2D.37,38 Since these initial trials, numerous clinical trials for DPP IV inhibitors have been conducted (for reviews and reports of the results of the clinical trials for approved drugs,65-70) resulting in the approval and marketing of six DPP IV inhibitors, collectively called the “gliptins”: 4 (sitagliptin/MK-0431),71 5 (vildagliptin/LAF237),42 6 (saxagliptin/BMS477118),72 7 (alogliptin/SYR-322),39 8 (linagliptin/BI-1356),73 and 9 (gemigliptin/LC150444)74,75 (Table 1).

Table 1: DPP IV inhibitors, the “gliptins” currently approved for clinical use.

The biological characteristics of the gliptins differ. Compound 471 is a reversible inhibitor, which is not rapidly metabolized in human, allowing a once a day dosing. Compound 5 forms a reversible covalent bond between its cyano group and the active site serine (Ser630), which is



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readily hydrolyzed into an inactive metabolite. Compound 5 is rapidly cleared, requiring twice daily dosing. Incorporation of steric bulk was one of the techniques used to improve the chemical stability of cyanopyrrolidines and this led to development of compounds 542 and 6.60,72 In the search for biologically stable DPP IV inhibitors azetidine-based compounds like 2cyanoazetidines, 3-fluoroazetidines and 2-ketoazetidines with activity below 100 nM were also developed.36 Compound 7 was discovered during attempts to increase the metabolic stability of quinazoline-based compounds by replacing the quinazoline moiety with pyrimidinedione.39 Compound 876 is a methylxanthine-based drug, exhibiting good selectivity for DPP IV compared to the other members of the family. X-ray studies of compound 8 complexed with DPP IV have shown that its butynyl substituent occupies the S1 hydrophobic pocket, the amino piperidine of the xanthine scaffold occupies the S2 subsite and its primary amine interacts with the key aminoacids of the substrate site. Compound 9 was only very recently approved and is presently marketed only in Korea. Its pharmacodynamic and pharmacokinetic properties allow for once a day dosing as a monotherapy for T2D. Extensive reviews of the pharmacotherapeutic characteristics of the gliptins in clinical studies in 2011 and 2012 (with the exception of 9 which was approved later than the others), their safety and efficacy profiles, have been recently published.77-79 The results of the clinical trials demonstrated excellent profiles for this class of therapeutics. However, long-term surveillance for the development of pancreatitis and/or pancreatic cancer, and a better understanding of the mechanism of action of the gliptins, other than the incretins protection and T2D wil be required.75 How do these gliptins differ between them, and how do they compare with other anti-diabetic therapies, from a clinical point of view? Unfortunately, presently, direct comparisons of the


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gliptins in head-to-head clinical trials are very scarce. Most of the clinical trials of gliptins have compared the decrease in glycated hemoglobin or plasma glucose versus placebo or an antidiabetic drug of another class. But the trial designs and the medical characteristics of the patient cohorts differed between the trials, thus adding to the inherent heterogeneity of human clinical trials. However, all authors

77, 79-83

who have analyzed these comparisons agree that the clinical

benefit and profile of the gliptins are generally very similar in term of efficacy and safety profiles, all inducing a decrease of glycated hemoglobin of about 0.8%, without episodes of hypoglycemia, without weight gain, and without adverse side-effects including gastrointestinal adverse effects as seen with metformin. No significant drug-drug interactions with the other antidiabetics have been observed. Compound 6 may interfere with CYP3A4/5 for the metabolism of other drugs. Initially, an increased risk of pancreatitis, and pancreas and thyroid cancers had been suggested for patients under gliptin therapy, but recent clinical analyses have not supported this possibility. There are some clinically relevant similarities and differences between these molecules. All gliptins are orally available, low nanomolar inhibitors of DPP IV activity (IC50: 19 nM for 4, 62 nM for 5, 50 nM for 6, 24 nM for 7 and 1 nM for 8), long-lasting (over 70% plasma DPP IV activity inhibition 24 h post-dose), do not interfere with food intake, and are selective at different levels versus DPP-8 and DPP-9, compounds 5 and 6 being the least selective. The inhibition of DPP-8 and DPP-9 was related to toxicity in preclinical evaluation, but it has to be remembered that species differences exist. The selectivity versus the other peptidases of the DPP IV family is less homogeneous; selectivity versus DPP-2 was always high, whereas 5 and 8 are less selective drugs versus FAP-α. Some DPP IV inhibitors are peptidomimetics (compounds 5 and 6), some are not (compounds 4 (β-aminoacid-based), 7 (pyrimidinedione-based), 8 (xanthine-based)). In



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general, the peptidomimetics are less selective for DPP IV versus DPP-8 and DPP-9. Inhibitors which form non-covalent interactions may result in potent immediate inhibition, but of shorter duration. Covalent inhibitors forming a reversible, slowly dissociating complex can result in more persistent inhibition. But drug metabolism also has to be considered. For example, the cyano group of compound 5 is hydrolyzed by DPP IV, thus 5 is both an inhibitor and a substrate of DPP IV. Covalent inhibitors are likely more prone to induce an antigenic reaction. Compounds 4 and 7 are not appreciably metabolized and are excreted unmodified by the kidney. Compound 5 is metabolized into inactive metabolites, whereas compound 6 is oxidatively metabolized into active metabolites, and both metabolites and drugs are excreted by the kidney. Renal elimination implies that the doses must be adjusted for patients with kidney disease. Interestingly, compound 8 is not extensively metabolized and is not excreted by the kidney but by biliary secretion, thus the clinical use of this gliptin does not require dose adjustment for patients with kidney diseases. Therapeutic dosages of the different gliptins are very different: 4 is used at 100 mg once a day, 5 at 50 mg twice a day, 7 at 25 mg once a day, and 6 and 8 at 5 mg once a day. Half-lives of the drugs in plasma are also very different: compounds 5 and 6 display the shortest plasma halflives, about two hours, in humans. However, 6 can be dosed once a day, even if displaying an apparent short half-life, since active metabolites are produced, while 5 needs to be dosed twice a day. It has also to be kept in mind that some of the drugs are covalent inhibitors, whose persistence of inhibition may last longer than suggested by plasma drug levels, which is particularly true for 5. Also very importantly, it has to be considered that most of the DPP IV in the human body is cell-bound, for which persistence of inhibition cannot be determined, rendering a direct evaluation of DPP IV inhibition in the clinic and the direct comparison of


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these drugs over time even more difficult. Thus, evaluation of DPP IV inhibition in plasma may not always be representative of the effect of DPP IV inhibitors in the tissues. Gliptins are generally considered as second-line therapy, after metformin therapy, in combination with another anti-diabetic agent. However, based on all the above considerations, the choice of a particular gliptin by the clinician will likely depend on the clinical characteristics of the patient.

More recent DPP IV inhibitors under development The clinical success of the gliptins following the initial approval of compound 4 has also stimulated the field to develop and evaluate additional DPP IV inhibitors, in order to obtain drugs with improved properties. Several excellent recent reviews have been published covering the development of potential new therapeutic DPP IV inhibitors,28,32,61 thus only the most relevant findings will be discussed in this Perspective, and only the very recent publications, covering 2011-early 2013 will be discussed here in more detail. Several new molecules have reached different phases of clinical trials (Table 2), including for example 14 (anagliptin/SK0403),84,85 18 (DA-1229),86 19 (E3024),87 20 (TAK-100),62 or the long-lasting compounds 10 (omarigliptin/MK-310288,89 (Table 2) and PKF-275-055 (structure not disclosed),90 or are in preclinical evaluation (Scheme 3).

Table 2: Examples of DPP IV inhibitors in different phases of clinical trials.

Starting from a xanthine scaffold deazaxanthine compounds were prepared as a novel class of DPP IV inhibitors.91 Peptidomimetic DPP IV inhibitors of the α-series are mainly represented by pyrrolidines, the C2 substituent allowing the design of irreversible (diphenyl-phosphonates and



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O-acylhydroxamic acid) or slowly reversible (boronic acid and nitrile) inhibitors. Some of the gliptins, even if displaying good oral bioavailability, also displayed a rapid clearance, requiring repeated dosing. Thus attempts have been made to develop long-acting inhibitors. One approach involves the design of cyanopyrrolidines, with very slow binding and dissociation rates. This approach was explored from the scaffold of compound 3, resulting in the phase 3 clinical trial of 10 (Table 2) and in compound 2692 (Scheme 3). The design of novel DPP IV inhibitors from the β-series peptidomimetics was also attempted, resulting in compound 28.93 Small modifications of already approved molecules were also explored, for example from the β-aminoamide backbone of compound 4 compound 25 was proposed.94 Isoindoline-based85 and pyrrolopyrimidine-based95 compounds were also developed through lead optimization as nanomolar highly selective DPP IV inhibitors. Many additional compounds have been described, based on various scaffolds and SAR modifications, which are not presented in this Perspective due only to space limitation. I apologize to the authors for not citing their work.

Scheme 4: Examples of recent development of DPP IV inhibitors.

The most recent developments of improved small molecule DPP IV inhibitors relied on computing approaches. Using such tools and chemical refinement of the lead structure 21 compound 22 (TAK-100) was developed,62,90,96 the first in its class to bear a carboxyl group to reach clinical trial, presently in phase 1. Using structure-based virtual screening of structural similarities of known inhibitors, and rigid or flexible docking programs of the cyanopyrrolidine moieties, the xanthines/pyrimidines parts and amino-like linkages, novel potential DPP IV inhibitors were proposed.96 Out of 99 virtual hits, 15 were evaluated and found to be DPP IV


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inhibitors, however, with high 5-50 µM IC50 values. But novel structures were also found, allowing refining the pharmacophore model. Based on the pyrazole-3-carbohydrazone scaffold, modeling approaches, chemical syntheses and SAR studies, compounds with 2-70 µM IC50 values for DPP IV inhibition were obtained.97 Using triazol substituted prolyl-fluoropyrrolidines, a series of potent and selective inhibitors with IC50 values ~1 µM were also obtained.98 Xanthinebased compounds were also developed, resulting in compounds with 1-30 µM IC50 values, and acceptable selectivity versus the other peptidases of the DPP IV family.99 Therefore, dockingbased approaches resulted in DPP IV inhibitors which were very selective for this enzyme, compared to DPP-8 and DPP-9, but with low inhibition potency. However, it can be postulated that pursuing these lead molecules may result in potentially interesting therapeutics for further clinical development. Approaches other than the syntheses of small inhibitors have also been explored. For T2D patients, changes in the diet may improve the condition, therefore it would be logical to look for DPP IV-active molecules in food, since the DPP IV-target incretin peptides are produced by the gut and DPP IV is expressed in the digestive tract. In support of this hypothesis, it has been previously shown, in the case of hypertension that angiotensin converting enzyme (ACE) inhibitory peptides can be found in food. Food sources of peptides capable of DPP IV inhibition have thus been sought and found. These include peptides from hydrolyzed αS1-casein (-Pro-PhePro-) and β-casein (-Pro-Leu-Pro-) of bovine milk,100 peptides from hydrolyzed salmon skin (Gly-Pro-Ala-Glu and Gly-Pro-Gly-Ala)101 or from tuna extracts.102 The amino acid sequences of these peptides suggest that they will act as competitive substrates. However, the IC50 values of these food-derived peptides for inhibiting DPP IV activity are generally much higher than the IC50 values of synthetic molecules, which may be overcome by their large abundance in the



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digestive tract during food intake.

Off-targets effects and potential use of DPP IV inhibitors in human diseases other than type 2 diabetes DPP IV is constitutively expressed on capillary endothelial cells, epithelial cells, hematopoietic cells and stem cells, and on activated lymphocytes (as CD26), and is a soluble active enzyme in plasma, lacking the transmembrane region and the cytoplasmic tail. The highest expression of DPP IV is observed in the proximal tubules of the kidney and the luminal membrane of epithelial cells of the small intestine. As already stated in the Introduction, many biologically active peptides are protected from general proteolytic degradation by evolutionary conserved prolines, either at the terminal or in the core of peptides, pointing to the biological importance and a high potential for drug discovery of prolyl-specific peptidases. Of the known human proteases only a few prolyl-specific proteases have been described which include exopeptidases and endopeptidases. DPP IV cleaves a dipeptide from the N-terminal side of peptides with a proline or an alanine at the second position of the amino acid chains of peptides. In addition to GLP-1 and GIP, other biologically active peptides can be substrates of DPP IV, resulting in truncated forms of these peptides. However, no other peptide hormone has yet been proved to be potentiated by DPP IV inhibitors in humans, even if it is obvious that GLP-1 and GIP are not the only biological substrates of DPP IV. It is hypothesized that DPP IV has over 35 potential peptide hormone substrates. For most of these other potential peptide substrates, the physiological relevance of their truncation by DPP IV has still to be demonstrated. However, from the known sequence of many peptides, some hypotheses can be proposed. We have previously reviewed these possibilities,31,32 therefore here I will only summarize this previous


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information and comment in more detail the new information published, and what is being undertaken toward extensive use of DPP IV inhibitors. Other potential substrates of DPP IV include PACAP, NPY or PYY, or β-MSH .103 Thus DPP IV inhibitors may have other applications in metabolic disorders, such as obesity. NPY is a substrate of DPP IV and is involved in the control of feeding, as is the analgesic peptide endomorphin-1; DPP IV inhibitors reduce appetite. DPP IV has an adipogenic effect through NPY cleavage, which may be released by DPP IV inhibitors.104 Beta-casomorphin, an opioid peptide of β-casein of milk is a good substrate of DPP IV. GLP-2, a gastrointestinal postprandial peptide, represents another potential substrate of DPP IV in disorders of the digestive tract. Therefore, DPP IV inhibitors may also prove useful as therapies for metabolic disorders other than T2D. Possible utility of DPP IV inhibitors in immune/inflammatory response, ischemia-reperfusion injury, heart failure, cancer, tissue remodeling and neurodegenerative diseases have also been suggested. Many patients with T2D are overweight, and also have hypertension and vascular and renal diseases. In the kidney, in animal model of hypertension, DPP IV inhibitors may potentiate the NPY-dependent cell proliferative effects of preglomerular microcirculation and glomeruli.105 Therefore, DPP IV inhibitors are generally considered to be kidney protective in animal models of diabetic nephropathy.106 However, care must be taken in extrapolating these positive effects of DPP IV inhibitors, since a few reports suggest a link between DPP IV inhibitors and renal impairment. Some reports suggest that the DPP IV inhibitor 4 may have a direct effect on the activation of kinases of intestinal cells, independent of DPP IV inhibition.107 Thus, possible offtarget effects must be considered. Generally, the published information supports a positive role of DPP IV inhibition in diseases of the kidney and the cardiovascular system. DPP IV inhibition may promote angiogenesis, affording a positive effect in diabetic patients, but also having a



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negative potential in cancer, by enhancing tumor angiogenesis and progression. DPP IV was shown to be down-regulated during neoplastic transformation, and DPP IV expression was inversely correlated to the progression and the grading of cancer.108-114 Thus, loss of DPP IV (and possibly of its activity) could be considered oncogenic. The DPP IV protein, not its enzymatic activity, is a cell adhesion-regulating factor. DPP IV expressed on endothelial cells is a receptor for tumor-associated fibronectin and has been shown to favor tumor cell adhesion and metastasis.115 Therefore no beneficial effects for inhibitors can be postulated in this context. However, not all published information agrees with this observation. We have shown a decreased vascular expression of DPP IV activity in human glioblastoma, and in an experimental model of glioblastoma.116 In support of this finding, a small boronic inhibitor of DPP IV-like peptidases had anti-tumor effects, which were hypothesized to be mediated by the immune system and FAP-α inhibition.117 The pharmacological blockade of DPP IV activity by compound 4 reduced the growth of skin tumors, possibly mediated by the associated fibroblasts.118 However, these authors did not consider that this type of fibroblasts may also express the related peptidase FAP-α, whose induced expression has been clearly associated with cancer progression. It has been shown in several published papers that blockade of FAP-α activity by small molecules or by antibodies resulted in anti-cancer efficacy in experimental animal models of cancer, again underlining the importance of considering the enzyme selectivity of these inhibitors. Therefore, published information has mostly shown that DPP IV is a tumor suppressor and a proliferation inhibitor, and that loss of DPP IV in cancer cells, and/or cancer-associated stromal cells, favors cancer progression, suggesting that inhibition of DPP IV has little interest in cancer, and may possibly be detrimental. In further support of this, no formal demonstration of the efficacy of inhibiting DPP IV in cancer has been provided.


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Immune and inflammatory disorders involve the sequential activation, then tissue recruitment of activated immune cells, the lymphocytes and the macrophages. Immune/inflammatory cell recruitment into organs is mediated by families of adhesion molecules and cytokines/chemokines locally produced by the inflamed tissue. CD26/DPP IV is a marker of immune/inflammatory cell activation in immune and inflammatory diseases,9 independently of its enzymatic activity, suggesting that inhibitors of this enzyme are not of interest in modulating leukocyte adhesion.119,120 However, the functions of immune/inflammatory cells are also fine-tuned by cytokines and chemokines peptides. Many biologically active cytokines and chemokines bear evolutionary conserved N-terminal X-Pro-sequences that play a major role in regulating their biological functions and modulating their activity, since the N-terminus of chemokines and cytokines is required for interaction with their cognate receptors. Thus, DPP IV truncation has important effects on these peptide functions, involving for example (more detailed reviews in31,32) the proinflammatory cytokines (IL-2, IL-6, IL-1β, IL-10, IL-12, IFN-γ, MIP1α, IL-3, TNF-α), the chemokines (SDF-1α, MIP-1beta/CCL4, RANTES/CCL5), or other inflammationmodulating peptides (substance P, neurotensin, bradykinin, leptin). Consequently, DPP IV inhibitors have received some interest in this context as relevant therapeutics for the treatment of diseases of the colon, joints, lung, or for neurodegeneration.12,121-123 However, it is not always clear which of these families of related prolyl-specific proteases are important in immune diseases. For example, DPP IV inhibitors were able to induce apoptosis even in DPP IV-negative lymphocytes,124 suggesting the inhibition of other enzymes with similar activity. Very recently, it was shown that des-fluoro-sitagliptin exhibited GLP-1-mediated anti-atherogenic effects in macrophages and endothelial cells by controlling inflammatory response.125 Also very recently, it was shown that the cytokine High Mobility Group Box-1, important in tissue regeneration and



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angiogenesis, is a potential substrate of DPP IV, which inhibits its pro-angiogenic properties.126 In ischemia/reperfusion127 it was also very recently shown that stabilization of SDF-1 through DPP IV inhibition increased the recruitment of regenerative stem cells to grafts, and improved recovery from ischemia-reperfusion in experimental lung transplantation,128 an observation which seems to be generally valid for all cell engraftment attempts. Therefore, inhibitors of DPP IV developed for T2D may be of use in the treatment of immune disorders involving both resident and recruited immune cells, but presently, in my opinion, it is not yet clear which inhibitor for which disease may be the most efficient as a combination with other therapeutics. Insulin signaling is desensitized in the brains of patients with Alzheimer’s disease, therefore it has been postulated that improving insulin signaling may have therapeutic interest for this devastating disease. In murine models of Alzheimer's disease, GLP-1 analogs have shown some neuroprotective effects. Thus, it can be hypothesized that DPP IV inhibitors by protecting GLP-1 from degradation, may also have a protective role.129 However, it was also shown that the phosphorylation of the Alzheimer’s disease-associated tau protein is increased in animal models of the disease exposed to compound 4, which represents a negative effect.130 Thus, apart from GLP-1, other biologically active peptides can be truncated by DPP IV. However, for these peptides the physiological relevance of their truncation has still to be demonstrated, in most situations.

What else and what is next? Several open questions are left concerning the use and effects of DPP IV inhibitors in medicinal chemistry. Among them, it will be important to:


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1) understand new clinical applications of DPP IV and its inhibitors. For example a phase 3 clinical trial is currently underway (http://clinicaltrials.gov; identifier NCTO1822548, sponsor: University Hospital of Parma, Italy) to evaluate the effect of compound 5 on the number of circulating endothelial progenitor cells in T2D patients; 2) validate the effects of DPP IV inhibitors on the metabolism of peptide hormones other than the incretins, in particular peptides which may be relevant for understanding the postulated role of DPP IV also in cancer progression, which is a major concern for the long-term use of these drugs; 3) evaluate the development of therapeutic small molecule inhibitors with a longer duration of action, as exemplified by the clinical trials initiated for compound 10, with once a week dosing; 4) evaluate the combination of DPP IV inhibitors with other anti-diabetic therapeutics, which has already started (for example, 7-metformin (trade-name: Kazano), or 7-pioglitazone (trade-name: Oseni) tablets), in order to improve glycemic control without enhancing side-effects; 5) develop new dual drug scaffolds represented by compounds bearing two therapeutic functionalities on one scaffold, one of them being a DPP IV inhibitor.

Conclusions In conclusion, the enzymatic action of DPP IV-related peptidases leads to both quantitative and qualitative changes in the signaling potential of bioactive peptides. CD26/DPP IV/DPP-4 is involved in the development and progression of metabolic and other disorders. DPP IV inhibitors may attenuate, or potentiate, the effects of peptides involved in these diseases, depending on the context of a particular disorder, or its stage of evolution. DPP IV-related peptidases have multiple substrates, and are located in different biological compartments. Therefore the effects,



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development and evaluation of inhibitors must be examined from the perspective of selectivity, cellular localization and transport through biological barriers. The possibility that indirect effects on the processing of peptides involved in the regulation of others pathways than the pathways initially targeted also needs consideration. Functional consequences of inhibiting related enzymatic activities may be similar, but due to differences in the (sub)cellular localization of the enzymes, inhibitors may have different effects. Families of covalent and non-covalent DPP IV inhibitors have been shown in clinical trials to potentiate the effects of biological peptides involved in metabolic disorders, such as T2D. Therefore inhibiting this enzyme was a favorable option. Well-tolerated, efficient and selective inhibitors have reached the market with few sideeffects over several years, and new inhibitors are under development and evaluation. In the context of T2D therapy, the development of DPP IV inhibitors with a high selectivity for DPP IV over the other enzymes of the family has provided drugs with an excellent safety profile, tolerability and efficacy. For T2D, the goal was to protect GLP-1 and GIP from degradation, and the selective inhibition of DPP IV was probably necessary. As families of enzymes display DPP IV-like activities, the selectivity of the therapeutic inhibitors for the actual target peptidase, DPP IV, has to be considered. The expression of DPP IV has been reported to be inversely correlated with the development and progression of cancer. Thus it may be detrimental over the long-term to inhibit this enzyme in cancer, while the inhibition of the closely related FAP-α would be favorable for cancer patients. Therefore, for their application in other human diseases, which is presently under investigation, inhibitors with less selectivity may be more interesting. Thus, in the follow up of possible development of cancer during DPP IV inhibition, less selective inhibitors may prove to be safer drugs than very selective inhibitors. The validity of this hypothesis can only be


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ascertained after long-term use of DPP IV-specific inhibitors. Therefore, although DPP IV inhibitors are beneficial and well-tolerated for T2D therapy, mainly in combination with other anti-diabetic drugs, adverse effects of DPP IV inhibitors have also been suggested, and these can only be assessed by long-term follow-up.

Acknowledgements I would like to thank W. Greenlee for his valuable suggetions and comments.

Author biography Lucienne Juillerat-Jeanneret obtained her PhD of the University of Geneva, Switzerland. After post-doctoral experiences at the University of Geneva and the University Hospital of Lausanne (CHUV), she joined the University Institute of Pathology of Lausanne as a tenured senior lecturer and a teacher at the University of Lausanne and the Swiss Federal Institute of Technology of Lausanne (EPFL). Her main research interests are focused at the interface between biomedicine, chemistry and biomaterials, to design and develop innovative devices to selectively deliver therapeutic drugs. She is also involved in the development of novel approaches for diagnosis, for therapy and for tissue engineering. The strategies investigated include nanotechonology and nanotherapeutics, and the design and evaluation of targeted chemotherapeutics for the treatment of cancer and degenerative diseases.



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*Correspondence to: Dr Lucienne Juillerat-Jeanneret, PhD, Privat Docent, MER University Institute of Pathology, CHUV-UNIL Bugnon 25 CH-1011 Lausanne Switzerland

phone : +41 21 314 7173 fax : +41 21 314 7115 e-mail : [email protected]


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Abbreviations: ADA

adenosine deaminase

CD26

cluster differentiation antigen 26

DASH

dipeptidylpeptidase IV activity and/or structure homologues

DPP

dipeptidyl peptidase

FAP-α

fibroblast activation protein-α/seprase

GLP-1

glucagon-like peptide 1

GIP

glucose-dependent insulinotropic polypeptide

IC50

inhibitor concentration inhibiting 50% of the enzyme activity

HbAc1

glycated hemoglobin

IL

interleukin

POP/PREP

prolyl oligopeptidase

QPP

quiescent cell proline dipeptidase

SAR

structure activity relationship

T2D

type 2 diabetes



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References 1.

Yaron, A.; Naider, F. Proline-dependent structural and biological properties of peptides

and proteins. Crit. Rev. Biochem. Mol. Biol. 1993, 28, 31-81.

2.

Busek, P.; Malik, R.; Sedo, A. Dipeptidyl peptidase IV activity and/or structure

homologues (DASH) and their substrates in cancer. Int. J. Biochem. Cell. Biol. 2004, 36, 408421.

3.

Chen, W. T.; Kelly, T.; Ghersi, G. DPPIV, seprase and related serine peptidases in

multiple cellular functions. Curr. Topics Dev. Biol. 2003, 54, 207-232.

4.

Mentlein, R. Dipeptidyl-peptidase IV (CD26)-role in the inactivation of regulatory

peptides. Reg Pept 1999, 85, 9-24.

5.

Polgar .L. The prolyl oligopeptidase family. Cell. Mol. Life Sci. 2002, 59, 349-362.

6.

Rosenblum, J. S.; Kosarich, J. W. Prolyl peptidases: a serine protease subfamily with

high potential in drug discovery. Curr. Op. Chem. Biol. 2003, 7, 496-504.

7.

Cunningham, D. F.; O’Connor, B. Proline specific peptidases. Biochim. Biophys. Acta

1997, 1343, 160-186.

8.

Sedo A, Malik R. Dipeptidyl peptidase IV-like molecules: homologous proteins or


Page 31 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


homologous activities. Biochem. Biophys. Acta 2001, 1550, 107-116.

9.

Fleischer, B. CD26: a surface protease involved in T-cell activation. Immunol. Today

1994, 15, 180-184.

10.

Gorrell, M. D. Dipeptidyl peptidase IV and related enzymes in cell biology and liver

disorders. Clin. Science 2005, 108, 277-292.

11.

Holst, J. J.; Deacon, C. F. Glucagon-like peptides 1 and inhibitors of dipeptidyl peptidase

IV in the treatment of type 2 diabetes mellitus. Curr. Op. Phamacol. 2004, 4, 589-596.

12.

Berger, Y.; Chapuis Bernasconi, C.; Neier, R.; Juillerat-Jeanneret, L. Determination of

intracellular prolyl/glycyl-specific proteases in intact living human cells using protoporphyrin IX production as a reporter system. Chem. Biol. 2005, 12, 867-872.

13.

Engel, M.; Hoffmann, T.; Wagner, L.; Wermann, M.; Heiser, U.; Kiefersauer, R.; Huber,

R.; Bode, W.; Demuth, H. U.; Brandstetter, H. The crystal structure of dipeptidyl peptidase IV (CD26) reveals its functional regulation and enzymatic mechanisms. Proc. Nat. Acad. Sci. USA 2003, 100, 5063-5068.

14.

Hiramatsu, H..; Yamamoto, A..; Kyono, K..; Higashiyama, Y..; Fukushima, C..; Shima,

H..; Sugiyama, S..; Inaka, K.; Shimizu, R. The crystal structure of human dipeptidyl peptidase IV (DPPIV) complex with diprotin A. J. Biol. Chem. 2004, 385, 561-564.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 32 of 62 32

15.

Rasmussen, H. B.; Branner, S.; Wiberg, F. C.; Wagtmann, N. Crystal structure of human

dipeptidyl peptidase IV/CD26 in complex with a substrate analog. Nat. Struct. Biol. 2003, 10, 19-25.

16.

Oefner, C.; D’Arcy, A.; Mac Sweeney, A.; Pierau, S.; Gardiner, R.; Dale, G. E. High-

resolution structure of human apo dipeptidyl peptidase IV/CD26 and its complex with 1-[({2[85-iodopyridin-2-yl)aminoethyl}amino)acetyl]-2-cyano-(S)-pyrrolodine. Acta Crystallog. 2003, D59, 1206-1212.

17.

Thoma, R.; Löffler, B.; Stihle, M.; Huber, W.; Ruf, A.; Henning, M. Structural basis of

proline-specific exopeptidase activity as observed in human dipeptidyl peptidase IV. Structure 2003, 11, 947-959.

18.

Fülöp, V.; Böcskei, Z.; Polgar, L. Prolyl oligopeptidase: an unusual β-propeller domain

regulates proteolysis. Cell 1998, 94, 161-170.

19.

Edmondson, S. D.; Mastracchio, A.; Beconi, M.; Colwell, L. F.; Habulihaz, B.; He, H.,

Kumar, S.; Leiting, B.; Lyons, K. A.; Mao, A.; Marsilio, F.; Patel, R. A.;, Wu, J. K.; Zhu, L.; Thornberry, N. A.; Weber, A. E.; and Parmee, E. R. Potent and selective proline derived dipeptidyl peptidase IV inhibitors. Bioorg. Med. Chem. Lett. 2004, 14, 5151-5155.

20.

Xu, J., Ok, H. O., Gonzalez, E. J., Colwell, L. F., Habulihaz, B., He, H., Leiting, B.,


Page 33 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Lyons, K. A., Marsilio, F., Patel, R. A., Wu, J. K., Thornberry, N. A., Weber, A. E., Parmee, E. R. Discovery of potent and selective beta-homophenylalanine based dipeptidyl peptidase IV inhibitors. Bioorg. Med. Chem. Lett. 2004, 14, 4759-4762.

21.

Xu, J.; Wei, L.; Mathvink, R.; He, J.; Park, Y. J.; He, H.; Leiting, B.; Lyons, K. A.;

Marsilio, F.; Patel, R. A.; Wu, J. K.; Thornberry, N. A.; Weber, A .E. Discovery of potent and selective phenylalanine based dipeptidyl peptidase IV inhibitors. Bioorg. Med. Chem. Lett. 2005, 15, 2533-2536.

22.

Xu, J.; Wei, L.; Mathvink, R.; Edmonson, S. D.; Eiermann, G. J.; He, H.; Leone, J. F.;

Leiting, B.; Lyons, K. A.; Marsilio, F.; Patel, R. A.; Patel, S. B.; Petrov, A.; Scapin, G.; Wu, J. K.; Thornberry, N. A.; Weber, A. E. Discovery of potent,selective, and orally bioavailable oxadiazole-based dipeptidyl peptidase IV inhibitors. Bioorg. Med. Chem. Lett. 2006, 16, 53735377.

23.

Zhao, K.; Lim, D. S.; Funaki, T.; Welch, J. T. Inhibition of dipeptidyl peptidase IV (DPP

IV) by 2-(2-amino-1-fluoro-propylidene)-cyclopentanecarbonitrile, a fluoroolefin containing peptido-mimetic. Bioorg. Med. Chem. 2003, 11, 207-215.

24.

Zhao, G.; Taunk, P. C.; Magnin, D. R.; Simpkins, L. M.; Robl, J. A.; Wang, A.;

Robertson, J. G.; Marcinkeviciene, J.; Sitkof, D. F.; Parker, R. A.; Kirby, M. S.; Hamann, L. G. Diprolyl nitriles as potent dipeptidylpeptidase IV inhibitors. Bioorg. Med. Chem. Lett. 2005, 15, 3992-3995.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 34 of 62 34

25.

Mentlein R. Therapeutic assessement of glucagon-like peptide-1 agonists compared with

dipeptidyl peptidase IV inhibitors as potential antidiabetic drugs. Exp. Op. Invest. Drugs 2005, 14, 57-64.

26.

Leiting, B.; Pryor, K. A.; Wu, J. K.; Marsilio, F.; Patel, R. A.; Craik, C. S.; Ellman, J. A.;

Cummings, R. T.; Thornberry, N. A. Catalytic properties and inhibition of proline-specific dipeptidyl peptidases II, IV and VII. Biochem. J. 2003, 371, 525-532.

27.

Evans, D. M. Dipeptidyl peptidase IV inhibitors. Idrugs 2002, 5, 577-585.

28.

Weber A. E. Dipeptidyl peptidase IV inhibitors for the treatment of diabetes. J. Med.

Chem. 2004, 47, 4135-4141.

29.

Deacon, C. F. MK-431 Merck. Curr .Op. Invest. Drugs 2005, 6, 419-426.

30.

Holst, J. J.; Deacon, C. F. Inhibition of the activity of dipeptidyl peptidase IV as a

treatment for type 2 diabetes. Diabetes 1998, 47, 1663-1670.

31.

Juillerat-Jeanneret, L. Prolyl-specific peptidases and their inhibitors in biological

processes. Curr. Chem. Biol. 1998, 2, 97-109.

32.

Juillerat-Jeanneret, L.; Gerber-Lemaire, S. The prolyl-aminodipeptidases and their


Page 35 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


inhibitors as therapeutic targets for fibrogenic disorders. Mini-Rev. Med. Chem. 2009, 9, 215226.

33.

Plamboeck, A.; Holst, J. J.; Carr, R. D.; Deacon, C. F. Neutral endopeptodase 24.11 and

dipeptidyl peptidase IV are both mediators of the degradation of glucagon-like peptide 1 in the anaestised pig. Diabetologia 2005, 48, 1882-1890.

34.

Ahn, J. H.; Shin, M. S.; Jun, M. A.; Jung, S. H.; Kang, S. K.; Kim, K. R.; Rhee, S. D.;

Kang, N. S.; Kim, S. Y.; Sohn, S. K.; Kim, S. G.; Jin, M. S.; Lee, J. O.; Cheon, H. G.; Kim, S. S. Synthesis, biological evaluation and structural determination of β-aminoacyl-containing cyclic hydrazine derivatives as dipeptidyl peptidase IV (DPP-IV) inhibitors. Bioorg. Med. Chem. Lett. 2007, 17, 2622-2628.

35.

Ahn, J. H.; Park, W. S.; Jun, M. A.; Shin, M. S.; Kang, S. K.; Kim, K. Y.; Rhee, S. D.;

Bae, M. A.; Kim, K. R.; Kim, S. G.; Kim, S. Y.; Sohn, S. K.; Kang, N. S.; Lee, J. O.; Lee, D. H.; Cheon, H. G.; Kim, S. S. Synthesis and biological evaluation of homopiperazine derivatives with beta-aminoacyl group as dipeptidyl peptidase IV inhibitors. Bioorg. Med. Chem. Lett. 2009, 18, 6525-6529.

36.

Kuhn, B.; Hennig, M.; Mattei, P. Molecular recognition of ligands in dipeptidyl peptidase

IV. Curr. Topics Med. Chem. 2007, 7, 609–619.

37.

Thornberry, N. A.; Weber, A. E. Discovery of JANUVIA (Sitagliptin), a selective



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 36 of 62 36

dipeptidyl peptidase IV inhibitor for the treatment of type-2 diabetes. Curr. Topics Med. Chem. 2007, 7, 557–568.

38.

White, J. Dipeptidyl peptidase-IV inhibitors: pharmacological profile and clinical use.

Clin. Diab. 2008, 26, 53–57.

39.

Feng, J.; Zhang, Z.; Wallace, M.; Stafford, J.; Kaldor, S.; Kassel, D.; Navre, M.; Shi, L.

Discovery of alogliptin: A potent, selective, bioavailable, and efficacious inhibitor of dipeptidyl peptidase IV. J. Med. Chem. 2007, 50, 2297–2300.

40.

Belyae, A.; Zhang, X.; Augustyns, K.; Lambeir, A. M.; De Meester, I.; Vedemikova, I.;

Scharpe, S.; Haemers, A. Structure-activity relationship of diaryl phosphonate esters as potent irreversible dipeptidyl peptidase IV inhibitors. J. Med. Chem. 1999, 42, 1041-1052.

41.

Villhauer, E. B.; Brinkman, J. A.; Naderi, G. B.; Dunning, B. E.; Mangold, B. L.; Mone,

M. D.; Russel, M .E.; Weldon, S. C.; Hughes, T. E. 1-[2-[(5-Cyanopyridin-2yl)amino]ethylamino] acetyl-2-(S)-pyrrolidinecarbonitrile: a potent, selective, and orally bioavailable dipeptidyl peptidase IV inhibitor with antihyperglycemic properties. J. Med. Chem. 2002, 45, 2362-2365.

42.

Villhauer, E. B.; Brinkman, J. A.; Naderi, G. B.; Burkey, B. N. F.; Dunning, B. E.;

Prasad, K.; Mangold, B. L.; Russell, M. E.; Hughes, T. E. 1-3[(3-hydroxy-1-adamantyl)amino] acetyl-2-cyano-(S)-pyrrolidine, a potent, selective, and orally bioavailable dipeptidyl peptidase


Page 37 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


IV inhibitor with antihyperglycemic properties. J. Med. Chem. 2003, 46, 2774-2789.

43.

Ferraris, D,; Ko, Y. S.; Calvin, D.; Chiou, T.; Lautar, S.; Thomas, B.; Wozniak, K.;

Rojas, C.; Kalish, V.; Belyakoy, S. Ketopyrrolidines and ketoazetidines as potent dipeptidyl peptidase IV (DPP IV) inhibitors. Bioorg. Med. Chem. Lett. 2004, 14, 5579-5583.

44.

Magnin, D. R.; Robl, J. A.; Sulsky, R. B.; Augeri, D. J.; Huang, Y.; Simpkins, L. M.;

Tanks, P. C.; Betebenner, D. A.; Robertson, J. G.; Abboa-Offei, B. E.; Wang, A.; Cap, M.; Xin, L.; Tao, L.; Sitkoff, D. F.; Malley, M. F.; Gougoutas, J. Z.; Khanna, A.; Huang, Q.; Han, S. P.; Parker, R. A.; Hamann, L. G. Synthesis of novel potent dipeptidyl peptidase IV inhibitors with enhanced chemical stability: interplay between the N-terminal amino acid alkyl side chain and the cyclopropyl group of alpha-aminoacyl-l-cis-4,5- methanoprolinenitrile-based inhibitors. J. Med. Chem. 2004, 47, 2587-2598.

45.

Peters, J. U.; Weber, S.; Kritter, S.; Weiss, P.; Wallier, A.; Boehringer, M.; Hennig, M.;

Kuhn, B.; Loeffler, B. M. Aminomethylpyrimidines as novel DPP-IV inhibitors: A 105-fold activity increase by optimization of aromatic substituents. Bioorg. Med. Chem. Lett. 2004, 14, 1491-1493.

46.

Sakashita, H.; Kitajima, H.; Nakamura, M.; Akahoshi, F.; Hayashi, Y. 1-((S)-γ-

Substituted prolyl)-(S)-2-cyanopyrrolidine as a novel series of highly potent DPP-IV inhibitors. Bioorg. Med. Chem. Lett, 2005, 15, 2441-2445.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 38 of 62 38

47.

Sakashita, H.; Akahoshi, F.; Kitajima, H.; Tsutsumiuchi, R.; Hayashi, Y. [(S)-γ-

(Arylamino)prolyl]thiazolidine compounds as a novel series of potent and stable DPP-IV inhibitors. Bioorg. Med. Chem. 2006, 14, 3662-3671.

48.

Sakashita, H.; Akahoshi, F.; Yoshida, T.; Kitajima, H.; Hayashi, Y.; Ishii, S.; Takashina,

Y.; Tsutsumiuchi, R.; Ono, S. Lead optimization of [(S)-γ-(arylamino)prolyl]thiazolidine focused on γ-substituent: Indoline compounds as potent DPP-IV inhibitors. Bioorg. Med. Chem. 2007, 15, 641-655.

49.

Haffner, C. D.; McDougald, D. L.; Reister, S. M.; Thompson, B. D.; Conlee, C.; Fang, J.;

Bass, J.; Lenhard, J. M.; Croom, D.; Secosky-Chang, M. B.; Tomaszek, T.; McConn, D.; WellsKnecht, K.; Johnson, P. R. 2-Cyano-4-fluoro-1-thiovalylpyrrolidine analogues as potent inhibitors of DPP-IV. Bioorg. Med. Chem. Lett, 2005, 15, 5257-5261.

50.

Fukushima, H.; Hiratate, A.; Takahashi, M.; Satio, M.; Munetomo, E.; Kitano, K.; Saito,

H.; Takaoka, Y.; Yamamoto, K. Synthesis and structure-activity relationships of potent 3- or 4substituted-2-cyanopyrrolidine dipeptidyl peptidase IV inhibitors. Bioorg. Med. Chem. 2005, 12, 6053-6061.

51.

Abe, M.; Akiyama, T.; Umezawa, Y.; Yamamoto, K.; Nagai, M.; Yamazaki, H.;

Ichikawa, Y.I.; Muraoka, Y. Synthesis and biological activity of sulphostin analogues, novel dipeptidyl peptidase IV inhibitors. Bioorg. Med. Chem., 2005, 13, 785-797.


Page 39 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


52.

Gilmore, B. F.; Carson, L.; McShane, L. L.; Quinn, D.; Coulter, W. A.; Walker, B.

Synthesis, kinetic evaluation, and utilization of a biotinylated dipeptide proline diphenyl phosphonate for the disclosure of dipeptidyl peptidase IV-like serine proteases. Bioorg. Med. Chem. 2006, 347, 373-379.

53.

Yoshida, T.; Sakashita, H.; Akahoshi, F.; Hayashi, Y. [(S)-γ-(4-Aryl-1-piperazinyl)-

lprolyl] thiazolidines as a novel series of highly potent and long-lasting DPP-IV inhibitors. Bioorg. Med. Chem. Lett, 2007, 17, 2618-2621.

54.

Kowalchick, J. E.; Leiting, B.; Pryor, K. D.; Marsilio, F.; Wu, J.K.; He, H.; Lyons, K. A.;

Eiermann, G. J.; Petrov, A.; Scapin, G.; Patel, R. A.; Thornberry, N. A.; Weber, A. E.; Kim, D. Design, synthesis, and biological evaluation of triazolopiperazine-based β-amino amides as potent, orally active dipeptidyl peptidase IV (DPP-IV) inhibitors. Bioorg. Med .Chem. Lett. 2007, 17, 5934-5939.

55.

Corbett, J. W.; Dirico, K.; Song, W.; Boscoe, B. P.; Doran, S. D.; Boyer, D.; Qiu, X.;

Ammirati, M.; VanVolkenburg, M. A.; McPherson, R .K.; Parker, J. C.; Cox, E. D. Design and synthesis

of

potent

amido-

and

benzyl-substituted

cis-3-amino-4-(2-cyanopyrrolidide)

pyrrolidinyl DPP-IV inhibitors. Bioorg. Med. Chem. Lett, 2007, 17, 6707-6713.

56.

Coumar, M. S.; Chang, C. N.; Chen, C. T.; Chen, X.; Chien, C. H.; Tsai, T. Y.; Cheng, J.

H.; Wu, H. Y.; Han, C. H.; Wu, S. H.; Huang, Y. W.; Hsu, T.; Hsu, L. J.; Chao, Y. S.; Hsieh, H. P.; Jiaang, W.T. 3-[2-((2S)-2-Cyano-pyrrolidin-1-yl)-2-oxo-ethylamino]-3-methylbutyramide



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 40 of 62 40

analogues as selective DPP-IV inhibitors for the treatement of type-II diabetes. Bioorg. Med. Chem. Lett. , 2077, 17, 1274-1279.

57.

Biftu, T.; Scapin, G.; Singh, S.; Feng, D.; Becker, J. W.; Eiermann, G.; He, H.; Lyons,

K.; Patel, S.; Petrov, A.; Roy, R. S.; Zhang, B.; Wu, J.; Zhang, X.; Doss, G. A.; Thornberry, N. A.; Weber, A. E. Rational design of a novel, potent, and orally bioavailable cyclohexylamine DPP-IV inhibitors by application of molecular modeling and X-ray crystallography of sitaliptin. Bioorg. Med. Chem. Lett. , 2007, 17, 3384-3387.

58.

Gao, Y. D.; Feng, D.; Sheridan, R. P.; Scapin, G.; Patel, S. B.; Wu, J. K.; Zhang, X.; Roy,

R. S.; Thornberry, N. A.; Weber, A. E.; Biftu, T. Modeling assisted rational design of novel, potent, and selective pyrrolopyrimidine DPP-IV inhibitors. Bioorg. Med. Chem.Lett, 2007, 17, 3877-3879.

59.

Kondo, T.; Nekado, T.; Sugimoto, I.; Ochi, K.; Takai, S.; Kinoshita, A.; Hatayama, A.;

Yamamoto, S.; Kishikawa, K.; Nakai, H.; Toda, M. Design and synthesis of DPP-IV inhibitors lacking the electrophilic nitrile group. Bioorg. Med. Chem. Lett. 2008, 16, 1613-1631.

60.

Peters, J. U. 11 years of cyanopyrrolidines as DPP-IV inhibitors. Curr. Topics Med.

Chem. 2007, 7, 579–595.

61.

Liu, Y.; Hu, Y.; Liu, T. Recent advances in non-peptidomimetic dipeptidyl peptidase 4

inhibitors: medicinal chemistry and preclinical aspects. Curr. Med. Chem. 2012, 19, 3982-3999.


Page 41 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


62.

Miyamoto, Y.; Banno, Y.; Yamashita, T.; Fujimoto, T.; Oi, S.; Moritoh, Y.; Asakawa, T.;

Kataoka, O.; Takeuchi, K.; Suzuki, N.; Ikedo, K.; Kosaka, T.; Tsubotani, S.; Tani, A.; Sasaki M, Funami, M.; Amano, M.; Yamamoto, Y.; Aertgeerts, K.; Yano, J.; Maezaki, H. Discovery of a 3pyridylacetamide derivative (TAK-100) as a potent, selective and orally active dipeptidyl peptidase IV (DPP-IV) inhibitor. J. Med. Chem. 2011, 54, 831-850.

63.

van der Veken, P.; Haemers, A.; Augustyns, K. Prolyl peptidase related to dipeptidyl

peptidase IV: Potential of specific inhibitors in drug discovery. Curr. Topics Med. Chem. 2007, 7, 621–635.

64.

Ristic, S.; Byiers, S.; Foley, J.; Holmes, D. Improved glycaemic control with dipeptidyl

peptidase-4 inhibition in patients with type 2 diabetes: vildagliptin (LAF237) dose response. Diabetes Obesity Metab. 2005, 7, 692-698.

65.

Russell-Jones, D.; Gough, S. Recent advances in incretin-based therapy. Clin Endocrinol.

2012, 77, 489-499.

66.

Cox, M. E.; Rowell, J.; Corsino, L.; Green, J. B. Dipeptidyl peptidase-4 inhibitors in the

management of type 2 diabetes: safety, tolerability, and efficacy. Drug Healthcare Patient Safety 2010, 2, 7-19.

67.

Keeks, E. D. Linagliptin: a review of its use in the management of type 2 diabetes



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 42 of 62 42

mellitus. Drugs 2012, 72, 1793-1824.

68.

Bohanson, N. Overview of the gliptin class (dipeptidyl peptidase-4 inhibitors) in clinical

practice. Postgrad. Med, 2009, 121.

69.

Karagiannis, T.; Paschos, P.; Paletas, K.; Matthews, D. R. ; Tsapas, A. Dipeptidyl

peptidase-4 inhibitors for treatment of type 2 diabetes mellitus in the clinical setting: systematic review and meta-analysis. BMJ 2012, 344, e1369.

70.

Derosa, G.; Maffioli, P. Dipeptidyl peptidase-4 inhibitors: 3 years of experience.

Diabetes Technol. Therap. 2012, 14, 350-364.

71.

Kim, D.; Wang, L.; Beconi, M.; Eiermann, G. J.; Fisher, M. H.; He, H.; Hickey, G. J.;

Kowalchick, J. E.; Leiting, B.; Lyons, K.; Marsilio, F.; McCann, M. E.; Patel, R. A.;, Petrov, A.; Scapin, G.; Patel, S. B.; Sinha, R.; Wu, J. K.; Wyvratt, M. J.; Zhang, B. B.; Zhu, L.; Thornberry, N. A.; Weber, A. E. (2R)-4-oxo-4-[3-(trifuloromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a-]pyrazin7(8H)-yl]-1-(2,4,5-trifluoro-phenyl) butan-2-amine: a potent orally active dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes. J. Med. Chem. 2005, 48, 141-151.

72.

Augeri, D. J.: Robl, J. A.; Khanna, A.; Robertson, J. G.; Wang, A.; Simpkins, L. M.;

Taunk, P.; Huang, Q.; Han, S. P.; Abboa-Offei, B;. Cap, M;. Xin, L.; Tao, L.; Tozzo, E.; Welzel G. E.; Egan D. M.; Marcinkeviciene J.; Chang, S. Y.; Biller S. A.; Kirby M. S.; Parker R. A.; Hamann, L G. Discovery and preclinical profile of Saxagliptin (BMS-477118): a highly potent,


Page 43 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


long-acting, orally active dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes. J. Med. Chem. 2005, 48, 5025-5037

73.

Eckhardt, M.; Langkop, E.; Mark, M.; Tadayyon, M.; Thomas, L.; Nar, H.; Pfengle, W.;

Guth, B.; Lotz, R.; Siegel, P.; Fuchs, H.; Himmelsbach, E. 8-[(3R)-3-aminopiperidin-1-yl]-7(but-2-yn-1-yl)-3-methyl-1-[(4-methylquinazolin-2-yl)methyl]-3,7-dihydro-1H-purine-2,6-dione (BI-1356) a highly potent, selective, long-acting, and orally bioavailable DPP-4 inhibitor for the treatment of type-2 diabetes. J. Med. Chem. 2007, 50, 6450-6453.

74.

Lim, K. S.; Cho, J. Y.; Kim, B. H.; Kim, J. R.; Kim, H. S.; Kim, D. K.; Kim, S. H.; Yim,

H. J.; Lee, S. H.; Shin, S. G.; Jang, I. J.; Yu, K. S. Pharmacokinetics and pharmacodynamics of LC15-0444, a novel dipeptidyl peptidase IV inhibitors, after multiple dosing in healthy volunteers. Br. J. Clin. Pharm. 2009, 68, 883-890.

75.

Yang, S. J.; Min, K. W.; Gupta, S. K.; Park, J. Y.; Shivane, V. K.; Pitale, S. U.; Agarwal,

P. K.; Sosale, A.; Gandhi, P.; Dharmalingam, M.; Mohan, V.; Makesh, U.; Kim, D. M.; Kim, J. A.; Kim, P. K.; Baik, S. H. A multicentre, multinational, randomized, placebo-controlled, double-blind, phase 3 trial to evaluate the efficacy and safety of gemigliptin (LC15-0444) in patients with type 2 diabetes. Diabetes Obesity Metab. 2013, 15, 410-416.

76.

Agrawal, R.; Pratima, J.; Dikshit, S. N. Linagliptin, a novel methylxanthin based

approved dipeptidyl peptidase-4 inhibitor. Curr. Drug Targets 2012, 13, 970-983.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 44 of 62 44

77.

Scheen, A. J. A review of gliptins in 2011. Expert Opin. Pharmacotherap. 2012, 13, 81-

99.

78.

Gueler, I.; Mueller, S.; Helmschrott, M.; Oeing, C. U.; Erbel, C.; Frankenstein, L.;

Gleissner, C.; Ruhpaewar, A.; Ehlerman, P.; Dengler, T. J.; Katus, H. A.; Doesch, A. O. Effects of vildagliptin (galvus) therapy in patients with type 2 diabetes. Drug Des. Dev. Ther. 2013, 7, 297-303.

79.

Matteuchi, E.; Gianpietro, O. Dipeptidyl peptidase-4 inhibition: linking chemical

properties to clinical safety. Curr. Med. Chem. 2011, 18, 4753-4760.

80.

Gupta, V.; Kaltra, S. Choosing a gliptin. Ind.J. Endocrinol. Metab. 2011, 15, 298-308.

81.

Aleskow Stein, S.; Lamos, E. M.; Davis, S. N. A review of the efficacy and safety of oral

antidiabetic drugs. Exp. Opin. Drug Saf. 2013, 12, 153-175.

82.

Landesdorfer, C. B.; He, Y. L.; Jusko, W. J. Mechanism-based population

pharmacokinetic modeling in diabetes: vildagliptin as a tight binding inhibitor and substrate of dipeptidyl peptidase IV. Br. J. Clin. Pharm, 2011, 73, 391-401.

83.

Gross, J. L.; Rogers, J.; Polhamus, D.; Gillespie W.; Friedrich, C.; Gong, Y.; Monz, B.

U.; Patel, S.; Staabm A.; Retlich, S. A novel model-based meta-analysis to indirectly estimate the comparative efficacy of two medications: an example using DPP-4 inhibitors, sitagliptin and


Page 45 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


linagliptin, intreatment of type 2 diabetes mellitus. BMJ Open, 2013, 3, e001844.

84.

Ervinna, N.; Mita, T.; Yasunari, E.; Azuma, K.; Tanaka, R.; Fujimura, S.; Sukmawati,

D.; Nomiyama, T.; Kanazawa, A.; Kawamori, R.; Fujitani, Y.; Watada, H. Anagliptin, a DPP-4 inhibitor, suppresses proliferation of vascular smooth muscles and monocyte inflammatory reaction and attenuates atherosclerosis in male apo E-deficient mice. Endocrinology 2013,154, 1260-1270.

85.

Kato, N.; Oka, M.; Murase, T.; Yoshida, M.; Sakairi, M.; Yakufu, M.; Yamashita, S.;

Yasuda, Y.; Yoshikawa, A.; Hayashi, Y.; Shirai, M.; Mizuno, Y.; Takeuchi, M.; Makino, M.; Takeda, M.; Kakigami, T. Synthesis and pharmacological characterization of potent, selective, and orally bioavailable isoindoline class dipeptidyl peptidase IV inhibitors. Org. Med. Chem. Lett., 2011, 1, 7.

86.

Kim, M. K.; Chae, Y. N.; Kim, H. D.; Yang, E. K.; Cho, E. J.; Choi, S. H.; Cheong, Y.

H.; Kim, H. S.; Kim, H. J.; Jo, Y. W.; Son, M. H.; Kim, S. H.; Shin, C. Y. DA-1229, a novel and potent DPP4 inhibitor, improves insulin resistance and delays the onset of diabetes. Life Sciences 2012, 90, 21-29.

87.

Yasuda, N.; Nagakura, T.; Inoue, T.; Yamazaki, K.; Katsutani, N.; Takenaka, O.; Clark,

R.; Matsuura, F.; Emori, E.; Yoshikawa, S.; Kira, K.; Ikuta, H.; Okada, T.; Saeki, T.; Asano, O.; Tanaka, I. E3024, 3-but-2-ynyl-5-methyl-2-piperazin-1-yl-3,5-dihydro-4H-imidazo [4,5-d] pyridazin-4-one tosylate, is a novel, selective and competitive dipeptidyl peptidase IV inhibitor.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 46 of 62 46

Eur. J. Pharm. 2006, 548, 181-187.

88.

Biftu, T. Society for Medicine Research, December 5, 2012, London, England.

89.

Brunavs, M.; Cowley, P.; Ward, S. E.; Weber, P. Recent disclosures of clinical

candidates. Drugs Fut. 2013, 38, 127-133.

90.

Akarte, A. S.; Srinvasan, B. P.; Gandhi, S. A novel long-acting DPP-IV inhibitor PKF-

275-055 stimulated cell proliferation resulting in improved glucose homeostasis in diabetics rats. Biochem. Pharm. 2012, 83, 241-252.

91.

Sutton, J. M.; Clark, D. E.; Dunsdon, S, J.; Fenton, G.; Fillmore, A.; Harris, N. V.; Higgs,

C.; Hurley, C. A.; Krintel, S. L.; MacKenzie, R. E.; Duttaroy, A.; Gangl, E.; Maniara, W.; Sedrani, R.; Namoto, K.; Ostermann, N.; Gerhartz, B.; Sirockin, F.; Trappe, J.; Hassiepen, U.; Baeschlin, D. K. Novel heterocyclic DPP-IV inhibitors for the treatment of type 2 diabetes. Bioorg. Med. Chem. Lett. 2012, 22, 1464-1468.

92.

Jadav, P.; Bahekar, R.; Shah, S. R.; Patel, D.; Joharapurkar, A.; Kshirsagar, S.; Jain, M.;

Shaikh, M.; Sairam, K. V. Long-acting peptidomimetics based DPP-IV inhibitors. Bioorg. Med. Chem. Lett. 2012, 22, 3516-3521.

93.

Kim, H. J.; Kwak, W. Y.; Min, J. P.; Sung, S. Y.; Kim, H. D.; Kim, M. K.; Kim, H. S.;

Park, K. J.; Son, M. H.; Kim, S. H.; Lee, B. J. Dipeptidyl peptidase-4 inhibitors with – amino


Page 47 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


amide scaffold; synthesis, SAR and biological evaluation. Bioorg. Med. Chem. Lett. 2012, 22, 5545-5549.

94.

Shan, Z.; Peng, M.; Fan, H.; Lu, Q.; Lu, P.; Zhao, C.; Chen, Y. Discovery of potent

dipeptidyl peptidase IN inhibitors derived from β-aminoamides bearing substituted [1,2,3]triazolopiperidines for the treatment of type 2 diabetes. Bioorg. Med.Chem. Lett. 2011, 21, 17311735.

95.

Xie, H.; Zeng, L.; Zeng, S.; Lu, X.; Zhang, G.; Zhao, X.; Cheng, N.; Tu, Z.; Li, Z.; Xu,

H.; Yang, Y. Novel pyrrolopyrimidine analogues as potent dipeptidyl peptidase IV inhibitors based on pharmacokinetic property-driven optimization. Eur. J. Med. Chem. 2012, 52, 205–212.

96.

Li, C.; Lu, W.; Lu, C.; Xia, W.; Shen, X.; Huang, J.; Liu, G.; Tang, Y. Identification of

diverse dipeptidyl peptidase IV inhibitors via structure-based virtual screening. J. Mol. Model. 2012, 18, 4033-4042.

97.

Wu, D.; Jin, F.; Lu, W.; Zhu, J.; Li, C.; Wang, W.; Tang, Y.; Jiang, H.; Huang, J.; Liu,

G.; Li, J. Synthesis, structure-activity relationship, and pharmacophore modeling studies of pyrazole-3-carbohydrazone derivatives as dipeptidyl peptidase IV inhibitors. Chem. Biol. Drug Des. 2012, 79, 897-906.

98.

Zhang, L.; Su, M.; Li, J.; Ji, X.; Wang, J.; Li, Z.; Li, J.; Liu, H. Design, synthesis,

structure-activity relationships, and docking studies of 1-(γ-1,2,3-triazol substituted prolyl)-(S)-



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 48 of 62 48

3,3-difluoropyrrolidines as a novel series of potent and selective dipeptidyl peptidase-4 inhibitors. Chem. Biol. Drug Des. 2013, 81, 198-207.

99.

Lin, K.; Cai, Z.; Wang, F.; Zhang, W.; Zhou, W. Synthesis and biological evaluation of

xanthine derivatives on dipeptidyl peptidase 4. Chem. Pharm. Bull. 2013, 61, 477-482.

100.

Juillerat-Jeanneret, L.; Robert, M. C.; Juillerat, M. A. Peptides from Lactobacillus

hydrolysates of bovine milk caseins inhibit prolyl-peptidases of human colon cells. J. Agr. Food Chem. 2011, 59, 370-377.

101.

Li-Chan, E. C. Y.; Huang, S.L.; Jao, C.L.; Ho, K. P.; Hsu, K. C. Peptides derived from

atlantic salmon skin gelatin as dipeptidyl-peptidase IV inhibitors. J. Agr. Food Chem. 2012, 60, 973-978.

102.

Huang, S. L.; Jao, C. L.; Ho, K. P.; Hsu, K. C. Dipeptidyl-peptidase IV inhibitory activity

of peptides derived from tuna cooking juice hydrolysates. Peptides 2012, 35, 114-121.

103.

Hsiung, H. M.; Smiley, D. L.; Zhang, X. Y.; Zhang, L.; Yan, L. Z.; Craft, L.; Heiman, M.

L.; Smith, D. P. Potent peptide agonists for human melanocortin 3 and 4 receptors derived from enzymatic cleavage of human β-MSH(5-22) by dipeptidyl peptidase I and dipeptidyl peptidase IV. Peptides 2005, 26, 1988-1996.

104.

Rosmanho-Salgado, J.; Marques, J. P. ; Estrada, M. ; Santana, M. ; Cortez, Y. ;


Page 49 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Grouzman, E. ; Cavadas, C. Dipeptidyl-peptidase IV by cleaving neuropeptide Y induces lipid accumulation and PPAR-expression. Peptides 2012, 37, 49-54.

105.

Jackson, E. K.; Kochanek, S. J.; Gillespie, D. G. Dipeptidyl peptidase IV regulates

proliferation of preglomerular vascular smooth muscle and mesangial cells. Hypertension 2012, 60, 757-764.

106.

Liu, W. J.; Xie, S. H.; Liu, Y. N.; Kim, W.; Jin, H. Y.; Park, S. K.; Shao, Y. M.; Park, T.

S. Dipeptidyl peptidase IV inhibitor attenuate kidney injury in streptozotocin-induced diabetic rats. J. Pharm. Exp. Therap. 2012, 340, 248-255.

107.

Sangle, G. V.; Läuffer, L. M.; Grieco, A.; Trivedi, S.; Iaboukov, R.; Brubaker, P. L.

Novel biological action of the dipeptidylpeptidase-IV inhibitor, Sitagliptin, as a glucagon-like peptide-1 secretagogue. Endocrinology 2012, 153, 564-573.

108.

Pethiyagoda, C. L.; Welch, D. R.; Fleming, T. P. Dipeptidyl peptidase IV (DPPIV)

inhibits cellular invasion of melanoma cells. Clin. Exp. Metastasis 2001, 18, 391-400.

109.

Wesley, U. V.; Albino, A. P.; Tiwari, S.; Houghton, A. N. A role for dipeptidyl peptidase

IV in suppressing the malignant phenotype of melanocytic cells. J. Exp. Med. 1999, 190, 311322.

110.

Wesley, U. V.; Tiwari, S.; Houghton, A. N. Role for dipeptidyl peptidase IV in tumor



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 50 of 62 50

suppression of human non small cell lung carcinoma cells. Int. J. Cancer 2004, 109, 855-866.

111.

Bogenrieder, T.; Finstad, C. L.; Freeman, R. H.; Papandreou, C. N.; Scher, H. I.; Albino,

A. P.; Reuter, V. E.; Nanus D. M. Expression and localization of aminopeptidase A, aminopeptidase N and dipeptidyl peptidase IV in benign and malignant human prostate tissue. Prostate 1997, 33, 225-232.

112.

Asada, Y.; Aratake, Y.; Kotani, T.; Marutsuka, K.; Araki, Y.; Ohtaki, S.; Sumiyoshi, A.

Expression of dipeptidyl aminopeptidase IV activity in human lung carcinoma. Histopathology 1993, 23, 265-270.

113.

Kajiyama, H.; Kikkawa, F.; Ino, K.; Shibata, K.; Mizutani, S. Expression of

CD26/dipeptidyl peptidase IV in endometrial adenocarcinoma and its negative correlation with tumor grade. Adv. Exp. Med. Biol. 2003, 524, 245-248.

114.

Kikkawa, F.; Kajiyama, H.; Shibata, K.; Ino, K.; Nomura, S.; Mitzutani S. Dipeptidyl

peptidase IV in tumor progression. Biochim. Biophys. Acta 2005, 1751, 45-51.

115.

Kajiyama, H.; Kikkawa, F.; Khin, E.; Shibata, K.; Ino, K.; Mizutani S. Dipeptidyl

peptidase IV overexpression induces up-regulation of E-cadherin and tissue inhibitors of matrix metalloproteinases, resulting in decreased invasive potential in ovarian carcinoma cells. Cancer Res. 2003, 63, 2278-2283.


Page 51 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


116.

Juillerat-Jeanneret, L.; Monnet-Tschudi, F.; Zürich, M. G.; Lohm, S.; Duijvestijn, A. M.;

Honegger, P. Regulation of peptidase activity in a three-dimensional aggregate model of brain tumor vasculature. Cell Tissue Res. 2003, 311, 53-59.

117.

Adams, S.; Miller G. T.; Jesson, M. I.; Watanabe, T.; Jones, B.; Wallner, B. P. PT-100, a

small molecule dipeptidyl peptidase inhibitor, has potent antitumor effects and augments antibody-mediated cytotoxicity via a novel immune mechanism. Cancer Res. 2004, 64, 54715480.

118.

Arwert, E. N.; Mentink, R. A.; Driskell, R. R.; Hoste, E.; Goldie, S. J.; Quist, S.; Watt, F.

M. Upregulation of CD26 expression in epithelial cells and stromal cells during wound-induced skin tumor formation. Oncogene 2012, 31, 992-1000.

119.

Steinbrecher A, Reinhold D, Quigley L, Gado A, Tresser N, Izikson L, Born I, Faust J,

Neubert K, Martin R, Ansorge S, Brocke S. Dipeptidyl peptidase IV in inflammatory CNS disease. Adv. Exp. Biol. Med. 2000, 477, 145-153.

120.

Wrenger, S.; Faust, J.; Mrestani-Klaus, C.; Fengler, A.; Stockel-Maschek, A.; Lorey, S.;

Kahne, T.; Brandt, W.; Neubert, K.; Ansorge, S. Reinhold, D. Downregulation of T-cell activation following inhibition of dipeptidyl peptidase IV/CD26 by the N-terminal part of the throboxane A2 receptor. J. Biol. Chem. 2000, 275, 22180-22186.

121.

Hillebrandt, M.; Rose, M.; Rüter, J.; Salama, A.; Mönnikes, H.; Klapp, B. F.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 52 of 62 52

Dipeptidylpeptidase IV (DP IV, CD26) in patients with inflammatory bowel disease. Scand. J. Gastro. 2001, 10, 1067-1072.

122.

Sedo, A.; Vlasicova, K.; Bartak, P.; Vespalec, R.; Vicar, J.; Simanek, V.; Ulrichova, J.

Quaternary benzo[c]phenanthridine alkaloids as inhibitors of aminopeptidase N and dipeptidyl peptidase IV. Phytother. Res. 2002, 16, 84-87.

123.

Busso, N.; Wagtmann, N.; Herling, C.; Chobaz-Péclat, V.;, Bischof-Delaloye, A.; So, A.;

Grouzman, E. Circulating CD26 is negatively associated with inflammation in human and experimental arthritis. Am. J. Pathol. 2005, 166, 433-442.

124.

Reinhold, D.; Hemmer, B.; Gran, B.; Steinbrecher, A.; Brocke, S.; Kahne, T.; Wrenger,

S.; Born, I.; Faust, J.; Neubert, K.; Martin, R.; Ansorge, S. Dipeptidyl peptidase IV (CD26): role in T cell activation and autoimmune disease. Adv. Exp. Med. Biol. 2000, 477, 155-160.

125.

Matsubara, J.; Sigiyama, S.; Sugamura, K.; Nakamura, T.; Fijiwara, Y.; Akiyama, E.;

Kurokawa, H.; Nozaki, T.; Ohba, K.; Konishi, M.; Maeda, H.; Izumiya, Y.; Kaikita, K.; Sumida, H.; Jinnouchi, H.; Matsui, K.; Mitsuyama, S. K.; Takeya, M.; Ogawa, H. A dipeptidyl peptidase4 inhibitor, des-fluoro-Sitagliptin, improves endothelial function and reduces atherosclerostic lesion formation in apolipoprotein E-deficient mice. J. Am. Coll. Cardiol. 2012, 59, 265-276.

126.

Marchetti, C.; Di Carlo, A.; Facchiano, F.; Senatore, C.; De Cristofaro R.; Luzi, A.;

Federici, M.; Romani, M.; Napolitano, M.; Capogrossi, M. C.; Germane, A. High mobility group


Page 53 of 62

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


box 1 is a novel substrate of dipeptidyl peptidase-IV. Diabetologia 2012, 55, 236-244.

127.

Matheeussen, V.; Jungrathmayr, W.; De Meester, I. Dipeptidyl peptidase 4 as a

therapeutic target in ischemia/reperfusion injury. Pharmacol. Therap. 2012, 136, 267-282.

128.

Jungraithmayr, W.; De Meester, I.; Matheeussen, V.; Baerts, L.; Arni, S.; Weder, W.

CD26/DPP-4 inhibition recruits regenerative stem cells via stromal cell-derived factor-1 and beneficially influences ischaemia-reperfusion injury in mouse lung transplantation. Eur. J. Cardio-Thorac. Surg. 2012, 41, 1166-1173.

129.

Corbett, A.; Pickett, J.; Burns, A.; Corcoran, J.; Dunnett, S. B.; Edison, P.; Hagan, J. J.;

Holmes, C.; Jones, E.; Katona, C.; Kearns, I.; Kehoe, P.; Mudher, A.; Passmore, A.; Shepherd, N.; Walsh, F.; Ballard, C. Drug repositioning for Alzheimer’s disease. Nat. Rev. Drug Disc. 2012, 11, 833-846.

130.

Kim, D. H.; Huh, J. W.; Jang, M.; Suh, J. H.; Kim, T. W., Park, J. S., Yoon, S. Y.

Sitagliptin increases tau phosphorylation in the hippocampus of rats with type 2 diabetes and in primary neuron cultures. Neurobiol. Dis. 2012, 46, 52-58.



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Page 54 of 62 54

Scheme 1: amino acids involved in the binding of inhibitors to DPP IV.


Page 55 of 62

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Scheme 2: binding modes of the different scaffold-based analogs in the DPP IV enzyme [adapted from61].



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Page 56 of 62 56

Scheme 3: DPP IV inhibitors evaluated in initial clinical trials. ___________________________________________________________________________ a) Peptide inhibitors Diprotin A: Ile-Pro-Ile ; Diprotin B: Val-Pro-Leu

b) Non-peptide inhibitors CH3 O N

NH2 O

Val-Pyr, 1

CH3

H N

N NH2

P32/98, 2

S

NC

N

N N H

O

CN

NVP-DPP728, 3

______________________________________________________________________


Page 57 of 62

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Scheme 4: Examples of recent development of DPP IV inhibitors. Lead

optimized

Me

Me

Me

Me Me

TAK-100

N

N H2N Me

Et

[ref] [62]

O

H2N

O

N

code (if available)

OH

NH

O

21 (1)*

Me

22 (30c)

[91]

O

O N

N

N

N

N

NH

N O

N

N

NH

N CN

CN

23 (3a)

24 (12g) F F

F

F

N N

N

N

N F

N

NH2 O

F

N N

F

NH2 O

F

F

[94]

F

F

F

25 (5d)

4 N

NVP-DPP728

N H

N

NC

[92]

NC

H N O

H N

16c

CN

CN

N O

O

26 (16c)

3 F

F

F

F

NH2 O

NH2 O

[93]

N

N F

F

N

NH

27 (lead 4)

28 (5m)

O

R

NC O Me

NH

CN

N

N O

[85]

30 (4b)

H N

O

NH2

CN

[95]

N

N N

N H

Me

29 (lead isoindoline)

S

Me

N

O

O

N O

N

N

NH2

Br



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Page 58 of 62 58

31 ( lead 6)

*:

32 (21j)

In this schema, the code number ( ) represents the code number attributed to the compound by

the authors in the original publication.


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Table 1: DPP IV inhibitors, the “gliptins” presently approved for clinical use. Name (IUPAC) codename

tradename

sitagliptin (4) MK-0431

Januvia

chemical structure

[ref] company / approval F

F F

(R)-4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro [1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-1(2,4,5-trifluorophenyl)butan-2-amine

vildagliptin (5) LAF237

F

N

[71]

Merck 2006 (USA)

[42]

Novartis 2008 (EU)

[72]

BMS; AstraZeneca 2009 (USA)

[39]

Takeda 2010 (Japan), 2013 (USA)

N

N

N

NH2 O

F F

Zomelis Galvus

HO

NH

O N

(S)-1-[N-(3-hydroxy-1-adamantyl)glycyl] pyrrolidine-2-carbonitrile

NC

saxagliptin (6) BMS-477118 Oglyza

O

H

HO

(1S,3S,5S)-2-[(2S)-2-amino-2(3-hydroxy-1-adamantyl)acetyl]2-azabicyclo[3.1.0]hexane-3-carbonitrile

H H

NH2 NC O

alogliptin (7)

SYR-322

Nesina

N H2N

N

(2-({6-[(3R)3-aminopiperidin-1-yl]-3-methyl2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl} methyl)benzonitrile

N

O

NC

O

linagliptin (8) BI-1356

Tradjenta Trajenta

N N

8-[(3R)-3-aminopiperidin-1-yl]-7-(but-2-yn-1-yl) -3-methyl-1-[(4-methylquinazolin-2-yl)methyl] -3,7-dihydro-1H-purine-2,6-dione

O

Zemiglo

N N

N

F F

N

NH2 O

F N

N

N

(3S)-3-amino-4-(5,5-difluoro-2-oxopiperidino) -1-[2,4-di(trifluoromethyl)-5,6,7,8-tetrahydropyrido [3,4-dipyrimidin-7-yl]butan-1-one

Boehringer; Lilly 2011 (USA)

NH2

O

gemigliptin (9) LC15-0444

[73]

N

N

F

F

F

F F

[74,75] LGLS; DPC; NOBEL 2012 (Korea)

___________________________________________________________________________ LGLS : LG Life Sciences ; DCPC: Double Crane Pharmaceuticals Co ; BMS : Bristol-Myers Squibb;



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Page 60 of 62 60

Table 2: A few examples of DPP IV inhibitors under different phases of clinical trials. name

code

structure F

omarigliptin (10) MK-3102

company clinical phase (comment)

H2N N N O

O N S CH3 O

Merck

and combinations)

F

dutogliptin (11) PHX1149

O

H N

HO

OH

B

III (1x/week,

Phenomenix

III

Glenmark

III

Mitsubishi Tanabe

III

Sanwa Kagaku Kenkyusho

III

Pfizer

III

N

HN

F

melogliptin (12) GRC-8200

N N

N

CN

N

H N

O S NH

tenegliptin (13) MP-513

N

N N

O

N

N

CN O

O

H N

N

N H3C CH3H

anagliptin (14) SK-0403

N N CH3

NH

gosogliptin (15) PF-734200

N

F

N

N

F O

N N

O NH2

F

carmegliptin (16) R-1579

Hoffmann-LaRoche II (discont) H3C H3C

O

N

O

O

RO-0730699 (17)

N

N H

N O

Hoffmann-LaRoche II (discont) CN


Page 61 of 62

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DA-1229 (18)

H3C

F

CH3 CH3

[86]

II

NH2 O O

N F

E-3024 (19)

NH CH3

O H3C

TAK-100 (20)

Dong-A

O

F

Eisai

[87]

I

Takeda

[62]

I

N

N N

N

NH

N

H3C

CH3 CH3 N

H2N

CH2CH3 O OH

CH3

___________________________________________________________________________ disc: discontinued



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Table of Content graphic (TOC)


Dipeptidyl Peptidase IV and Its Inhibitors - ACS Publications

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