Homodimers of Vanillin and Apocynin Decrease the Metastatic

Subscriber access provided by UB + Fachbibliothek Chemie | (FU-Bibliothekssystem)

Article

Homo-Dimers of Vanillin and Apocynin Decrease Metastatic Potential of Human Cancer Cells by Inhibiting the FAK/PI3K/Akt Signaling Pathway Phatcharida Jantaree, Kriengsak Lirdprapamongkol, Wilailak Kaewsri, Charnsak Thongsornkleeb, Kiattawee Choowongkomon, Korakot Atjanasuppat, Somsak Ruchirawat, and Jisnuson Svasti J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.6b05697 • Publication Date (Web): 01 Mar 2017 Downloaded from http://pubs.acs.org on March 2, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Journal of Agricultural and Food Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 31

Journal of Agricultural and Food Chemistry

1

Homo-Dimers of Vanillin and Apocynin Decrease Metastatic Potential of Human

2

Cancer Cells by Inhibiting the FAK/PI3K/Akt Signaling Pathway

3 4

Phatcharida Jantaree,†,‡,§ Kriengsak Lirdprapamongkol,*,‡,§ Wilailak Kaewsri,†,‡ Charnsak

5

Thongsornkleeb,†,⊥ Kiattawee Choowongkomon,∇ Korakot Atjanasuppat,§ Somsak

6

Ruchirawat,†,‡,ǁ Jisnuson Svasti†,§

7 8

†

Chulabhorn Graduate Institute, Bangkok 10210, Thailand

9

‡

Center of Excellence on Environmental Health and Toxicology (EHT), Ministry of

10

Education, Bangkok 10400, Thailand

11

§

12

Medicinal Chemistry, Chulabhorn Research Institute, Bangkok 10210, Thailand

13

∇

14

Thailand

Laboratory of Biochemistry, ⊥Laboratory of Organic Synthesis, and ǁLaboratory of

Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok 10903,

15 16

*Corresponding author: Tel: +66 2553 8555 ext 8356. Fax: +66 2553 8572. E-mail:

17

[email protected]

18 19

Short title: Anti-Metastatic Potential of Vanillin and Apocynin Homo-Dimers

20 21 22 23 24 25

ACS Paragon Plus Environment

1


26

Page 2 of 31

ABSTRACT

27

The spread of cancer cells to distant organs, in a process called metastasis, is the main

28

factor that contributes to most death in cancer patients. Vanillin, the vanilla flavoring agent,

29

has been shown to suppress metastasis in a mouse model. Here, we evaluated the anti-

30

metastatic potential of the food additive divanillin, the homo-dimer of vanillin, and their

31

structurally related compounds, apocynin and diapocynin, in hepatocellular carcinoma cells.

32

The Transwell invasion assay showed that the dimeric forms exhibited higher potency than

33

vanillin and apocynin in inhibiting invasion, with IC50 values of 23.3±7.4 to 41.3±4.2 µM for

34

the dimers, which are 26-34 fold lower than IC50 values of vanillin and apocynin (p divanillin > apocynin

282

> vanillin, indicating that the vanilloid dimers were more potent than their monomeric forms

283

in binding to the FAK FERM domain. This ranking also corresponds to the anti-invasion

284

potential of the test compounds (Table 1), as well as their inhibitory effects on FAK and Akt

285

phosphorylation (Figure 4). The predicted ligand-protein interactions of divanillin, vanillin,

286

and apocynin show several interactions with amino acid side chains at the Y397 pocket site

287

of FERM domain, including hydrogen bonds with Y397 (Figure S4 in supporting

288

information). Diapocynin showed the highest numbers of interactions with the target site,

289

although diapocynin did not form a hydrogen bond with Y397, it could form five hydrogen

290

bonds with R35 and H58, making its binding affinity stronger than other test compounds

291

(Figure S4 in supporting information). Taken together, these results imply that a mechanism

292

underlying the anti-metastatic potential of divanillin and diapocynin involves inhibition of

293

FAK activation by interfering with Y397 phosphorylation.

294 295 296

Discussion The role of vanillin and divanillin in food flavoring is recognized, but these compounds

297

also have potential benefit for improving cancer treatment. This study reports the anti-

298

metastatic potential of divanillin and diapocynin, which are the homo-dimers of vanillin and

299

apocynin. Thus, the vanilloid dimers possess higher potency than their monomeric forms in


12

Page 13 of 31


300

terms of inhibiting cancer cell invasion and migration, as well as the regulatory pathways

301

involved. To our knowledge, this is the first report to show bioactivity of divanillin and

302

diapocynin in cancer cells.

303

Several dimeric compounds possess higher potency compared to their monomeric

304

forms. Thus, 3-hydroxytyrosol dimer is more potent than the monomer in protecting

305

keratinocytes against UV-induced cell death 34. Additionally, dimeric compounds of

306

oleanolic acid are more efficient in inhibiting growth of several cancer cell lines, compared to

307

monomeric compounds 35, while the dimer of p-coumaric acid is more effective than the

308

monomer in inhibition of tyrosinase 36. Interestingly, diapocynin also showed greater efficacy

309

than apocynin in inhibition of NADPH oxidase enzymatic activity 24, and in downregulating

310

expression of an NADPH oxidase subunit gene (gp91phox) 37, as well as in decreasing the

311

release of TNF-α and IL-10 pro-inflammatory cytokines, and CCL2 chemokine from

312

stimulated cells 37-38. All of these reports are in agreement with our results using an in vitro

313

anti-metastatic model, where the vanilloid dimers (divanillin and diapocynin) were found to

314

be more potent than their monomeric forms (vanillin and apocynin) in suppressing the

315

metastatic potential of HepG2 human liver cancer cells.

316

During cell invasion, the migrating cells grip the ECM components at the leading edge

317

to establish focal adhesion points by using integrins, then pull the cell body forward followed

318

by detachment of focal adhesion at the rear of the cells 39. Integrin-ECM interaction induces

319

autophosphorylation of FAK which subsequently activates PI3K/Akt signaling, as well as

320

Rho GTPases, via the PI3K product - PIP3. Activation of Rho GTPases, such as Rac and

321

Cdc42, promotes actin polymerization at the leading edge, resulting in formation of filopodia

322

and lamellipodia 30. In the present study, we used a model of cell-ECM attachment which

323

occurs during cell invasion and migration. The results showed that PI3K/Akt signaling is

324

downstream of FAK activation, since treatment with FAK inhibitor inhibits Akt


13


Page 14 of 31

325

phosphorylation, while PI3K inhibitor does not affect FAK phosphorylation (Figure 5). Our

326

results also showed that divanillin and diapocynin, as well as their monomeric forms, could

327

inhibit the FAK/PI3K/Akt signaling pathway. In the case of the FAK inhibitor I, FAK

328

activation is blocked when the phosphorylation of Y397 is interfered with by the binding of

329

the inhibitor to the Y397 pocket of the FERM domain of FAK 33. Molecular docking was

330

used to study the binding of divanillin, diapocynin, vanillin and apocynin to FAK. These

331

vanilloid compounds could bind to the same binding site as the FAK inhibitor I. Therefore,

332

the higher anti-invasion and anti-migration effects of the vanilloid dimers compared to the

333

monomers presumably results from the increased interactions with amino acids in the Y397

334

pocket of the FERM domain of FAK. Consistent with our report, inhibition of

335

FAK/PI3K/Akt signaling has been shown to mediate anti-invasion and anti-migration effects

336

of several compounds in foods, such as hispolon from Phellinus linteus mushroom 40, antcin

337

K form Antrodia cinnamomea mushroom 41, and nobiletin from citrus fruits 42. Recently,

338

apocynin was reported to show inhibitory effect on FAK phosphorylation, as well as on

339

migration and invasion of U251 glioma cells under hypoxia 43. Thus, we suggest that

340

inhibition of the FAK/PI3K/Akt signaling pathway is the mechanism underlying the anti-

341

metastatic potential of divanillin and diapocynin in our cellular model.

342

Other vanilloid compounds in food have also been reported to decrease the metastatic

343

potential of cancer cells. For example, capsaicin suppressed invasion and migration of HT-

344

1080 fibrosarcoma cells 44. 6-Gingerol and 6-shogaol reduced invasiveness of MDA-MB-231

345

breast cancer cells and Hep3B hepatocellular carcinoma cells 45-46. Ferulic acid attenuated

346

invasion and migration of H1299 lung cancer cells 47. Although the mechanism of action of

347

these vanilloid compounds are diverse, the anti-metastatic potential shared by the vanilloid

348

compounds, such as divanillin and diapocynin, make these compounds of interest for further

349

study, as modulators derived from foods for controlling cancer metastasis.


14

Page 15 of 31


350

In conclusion, our results demonstrate that divanillin and diapocynin could decrease the

351

metastatic potential of HepG2 liver cancer cells, by using a similar target to vanillin and

352

apocynin, but with greater potency. Since vanillin and divanillin are generally regarded as

353

safe, therefore, the health benefit of these food additives may be of interest for further study,

354

in addition to their role in food flavoring.

355 356

Conflicts of interest

357

None

358 359 360

Acknowledgments This work was supported by grants from the Chulabhorn Research Institiute, the

361

Chulabhorn Graduate Institute and the Center of Excellence on Environmental Health and

362

Toxicology (EHT), Ministry of Education. We would like to thank Professor Dr. Gerd

363

Dannhardt and Dr. Jan-Peter Kramb, Department of Pharmacy and Biochemistry, Johannes

364

Gutenberg University of Mainz, for supporting preliminary synthesis of diapocynin. We are

365

grateful to Assoc. Prof. Dr. Montip Tiensuwan, Department of Mathematics, Faculty of

366

Science, Mahidol University, for assistance with the statistical analysis.

367 368 369

Supporting Information Dimeric compound synthesis and NMR spectra, binding interfaces between the Y397

370

pocket on FERM domain of FAK and the FAK inhibitor I, 2D diagrams of molecular

371

interactions between the Y397 pocket on FERM domain of FAK and test compound. This

372

material is available free of charge via the Internet at http://pubs.acs.org.

373 374


15


Page 16 of 31

375

References

376

1.

377

J.; Qiu, S. J.; Li, Y.; Ji, X. N.; Liu, H.; Xia, J. L.; Wu, Z. Q.; Fan, J.; Ma, Z. C.; Zhou, X. D.;

378

Lin, Z. Y.; Liu, K. D. A decade's studies on metastasis of hepatocellular carcinoma. J.

379

Cancer Res. Clin. Oncol. 2004, 130, 187-96.

380

2.

381

2011, 331, 1559-1564.

382

3.

383

microenvironment. Curr. Opin. Cell Biol. 2015, 36, 13-22.

384

4.

385

Semin. Cancer Biol. 2001, 11, 143-52.

386

5.

387

prevention and intervention. Cancer Res. 1995, 55, 1856-62.

388

6.

389

Y.; Singhirunnusorn, P.; Ruchirawat, S.; Svasti, J.; Saiki, I. Vanillin suppresses in vitro

390

invasion and in vivo metastasis of mouse breast cancer cells. Eur. J. Pharm. Sci. 2005, 25,

391

57-65.

392

7.

393

1977, 15, 633-638.

394

8.

Walton, N. J.; Mayer, M. J.; Narbad, A. Vanillin. Phytochemistry 2003, 63, 505-15.

395

9.

Pyysalo, T.; Honkanen, E.; Hirvi, T. Volatiles of wild strawberries, Fragaria vesca L.,

396

compared to those of cultivated berries, Fragaria. times. ananassa cv Senga Sengana. J. Agric.

397

Food Chem. 1979, 27, 19-22.

398

10.

399

compounds. J. Agric. Food Chem. 1997, 45, 883-888.

Tang, Z. Y.; Ye, S. L.; Liu, Y. K.; Qin, L. X.; Sun, H. C.; Ye, Q. H.; Wang, L.; Zhou,

Chaffer, C. L.; Weinberg, R. A. A Perspective on Cancer Cell Metastasis. Science

Clark, A. G.; Vignjevic, D. M. Modes of cancer cell invasion and the role of the

Stetler-Stevenson, W. G.; Yu, A. E. Proteases in invasion: matrix metalloproteinases.

Kohn, E. C.; Liotta, L. A. Molecular insights into cancer invasion: strategies for

Lirdprapamongkol, K.; Sakurai, H.; Kawasaki, N.; Choo, M. K.; Saitoh, Y.; Aozuka,

Opdyke, D. Monographs on fragrance raw materials: Vanillin. Food Cosmet. Toxicol.

Sakho, M.; Chassagne, D.; Crouzet, J. African mango glycosidically bound volatile


16

Page 17 of 31


400

11.

Goodner, K. L.; Jella, P.; Rouseff, R. L. Determination of vanillin in orange,

401

grapefruit, tangerine, lemon, and lime juices using GC-olfactometry and GC-MS/MS. J.

402

Agric. Food Chem. 2000, 48, 2882-6.

403

12.

404

Accumulation of vanillin during barrel-aging of white, red, and model wines. J. Agric. Food

405

Chem. 1997, 45, 2584-2589.

406

13.

407

protocatechuic aldehyde with freshly prepared Guinea pig liver slices. Cell. Physiol.

408

Biochem. 2005, 15, 89-98.

409

14.

410

effects on mechanical hypersensitivity in a rat model of neuropathic pain. Phytother. Res.

411

2010, 24, 525-30.

412

15.

413

angiogenic, anti-inflammatory and anti-nociceptive activities of vanillin in ICR mice. Biomol.

414

Ther. 2008, 16, 132-136.

415

16.

416

improves and prevents trinitrobenzene sulfonic acid-induced colitis in mice. J. Pharmacol.

417

Exp. Ther. 2009, 330, 370-6.

418

17.

419

metalloproteinase-9 expression through down-regulation of nuclear factor-kappaB signaling

420

pathway in human hepatocellular carcinoma cells. Mol. Pharmacol. 2009, 75, 151-7.

421

18.

422

and biophysical properties of a NADPH oxidase inhibitor. Molecules 2013, 18, 2821-39.

Spillman, P. J.; Pollnitz, A. P.; Liacopoulos, D.; Skouroumounis, G. K.; Sefton, M. A.

Panoutsopoulos, G. I.; Beedham, C. Enzymatic oxidation of vanillin, isovanillin and

Beaudry, F.; Ross, A.; Lema, P. P.; Vachon, P. Pharmacokinetics of vanillin and its

Lim, E. J.; Kang, H. J.; Jung, H. J.; Song, Y. S.; Lim, C. J.; Park, E. H. Anti-

Wu, S. L.; Chen, J. C.; Li, C. C.; Lo, H. Y.; Ho, T. Y.; Hsiang, C. Y. Vanillin

Liang, J. A.; Wu, S. L.; Lo, H. Y.; Hsiang, C. Y.; Ho, T. Y. Vanillin inhibits matrix

Petronio, M. S.; Zeraik, M. L.; Fonseca, L. M.; Ximenes, V. F. Apocynin: chemical


17


Page 18 of 31

423

19.

Chian, C. F.; Chiang, C. H.; Yuan-Jung, C.; Chuang, C. H.; Liu, S. L.; Yi-Han, J.;

424

Zhang, H.; Ryu, J. H. Apocynin attenuates lipopolysaccharide-induced lung injury in an

425

isolated and perfused rat lung model. Shock 2012, 38, 196-202.

426

20.

427

Dannhardt, G.; Svasti, J. Vanillin suppresses metastatic potential of human cancer cells

428

through PI3K inhibition and decreases angiogenesis in vivo. J. Agric. Food Chem. 2009, 57,

429

3055-63.

430

21.

431

Portoghese, P. S.; Waddell, W. J.; Wagner, B. M.; Adams, T. B. GRAS Flavoring Substances

432

22. Food Technol. 2005, 59, 24-62.

433

22.

434

sources and enzymatic generation. Flavour Frag. J. 2015, 30, 362-365.

435

23.

436

products. Food Chem. 1997, 60, 43-51.

437

24.

438

Ishmael, F.; O'Donnell, R. W.; Chang, M. M.; Hogg, M. G.; Dordick, J. S.; Santhanam, L.;

439

Ziegler, L. M.; Holland, J. A. Inhibition of NADPH oxidase activation in endothelial cells by

440

ortho-methoxy-substituted catechols. Endothelium 2002, 9, 191-203.

441

25.

442

formulation and analysis of diapocynin. J. Agric. Food Chem. 2008, 56, 301-6.

443

26.

444

apocynin catalyzed by myeloperoxidase: proposal for NADPH oxidase inhibition. Arch.

445

Biochem. Biophys. 2007, 457, 134-41.

Lirdprapamongkol, K.; Kramb, J. P.; Suthiphongchai, T.; Surarit, R.; Srisomsap, C.;

Smith, R. L.; Cohen, S. M.; Doull, J.; Feron, V. J.; Goodman, J. I.; Marnett, L. J.;

Krings, U.; Esparan, V.; Berger, R. G. The taste enhancer divanillin: a review on

Anklam, E.; Gaglione, S.; Müller, A. Oxidation behaviour of vanillin in dairy

Johnson, D. K.; Schillinger, K. J.; Kwait, D. M.; Hughes, C. V.; McNamara, E. J.;

Luchtefeld, R.; Luo, R.; Stine, K.; Alt, M. L.; Chernovitz, P. A.; Smith, R. E. Dose

Ximenes, V. F.; Kanegae, M. P.; Rissato, S. R.; Galhiane, M. S. The oxidation of


18

Page 19 of 31


446

27.

Lirdprapamongkol, K.; Mahidol, C.; Thongnest, S.; Prawat, H.; Ruchirawat, S.;

447

Srisomsap, C.; Surarit, R.; Punyarit, P.; Svasti, J. Anti-metastatic effects of aqueous extract of

448

Helixanthera parasitica. J. Ethnopharmacol. 2003, 86, 253-6.

449

28.

450

Screening with GOLD. In Virtual Screening in Drug Discovery; Shoichet, B., Alvarez, J.,

451

Eds.; Taylor & Francis CRC Press: Boca Raton, Florida, 2005; pp. 379-415.

452

29.

453

the FERM domain of focal adhesion kinase. J. Biol. Chem. 2006, 281, 252-9.

454

30.

455

Mol. Cell Biol. 2004, 5, 816-26.

456

31.

457

leukemia. Front. Oncol. 2014, 4, 99.

458

32.

459

invasion of HT1080 cells by inhibiting the focal adhesion kinase pathway downstream of

460

Rac1-ROS signaling. Mol. Cells 2012, 33, 141-149.

461

33.

462

Cance, W. G. A small molecule inhibitor, 1,2,4,5-benzenetetraamine tetrahydrochloride,

463

targeting the y397 site of focal adhesion kinase decreases tumor growth. J. Med. Chem. 2008,

464

51, 7405-16.

465

34.

466

biocatalytically produced hydroxytyrosol dimer protects against ultraviolet-induced cell death

467

in human immortalized keratinocytes. J. Agric. Food Chem. 2012, 60, 11509-17.

468

35.

469

dimers linked at C-28 and evaluation of anti-tumor activity. Eur. J. Med. Chem. 2015, 89,

470

480-9.

Cole, J. C.; Nissink, J. W. M.; Taylor, R. Protein–Ligand Docking and Virtual

Ceccarelli, D. F.; Song, H. K.; Poy, F.; Schaller, M. D.; Eck, M. J. Crystal structure of

Guo, W.; Giancotti, F. G. Integrin signalling during tumour progression. Nat. Rev.

Shishido, S.; Bonig, H.; Kim, Y. M. Role of integrin alpha4 in drug resistance of

Park, S. J.; Jeon, Y. J. Dieckol from Ecklonia cava suppresses the migration and

Golubovskaya, V. M.; Nyberg, C.; Zheng, M.; Kweh, F.; Magis, A.; Ostrov, D.;

Zwane, R. E.; Parker, A.; Kudanga, T.; Davids, L. M.; Burton, S. G. Novel,

Cheng, K. G.; Su, C. H.; Yang, L. D.; Liu, J.; Chen, Z. F. Synthesis of oleanolic acid


19


Page 20 of 31

471

36.

Criton, M.; Le Mellay-Hamon, V. Dimeric cinnamoylamide derivatives as inhibitors

472

of melanogenesis. Biol. Pharm. Bull. 2011, 34, 420-5.

473

37.

474

Fonseca, L. M.; Ximenes, V. F. Diapocynin versus apocynin as pretranscriptional inhibitors

475

of NADPH oxidase and cytokine production by peripheral blood mononuclear cells.

476

Biochem. Biophys. Res. Commun. 2010, 393, 551-4.

477

38.

478

methoxyphenolic compounds on human airway cells. J. Inflamm. (Lond.) 2012, 9, 6.

479

39.

480

Cancer 1997, 80, 1529-37.

481

40.

482

Huang, S. S.; Hu, M. L. Hispolon suppresses SK-Hep1 human hepatoma cell metastasis by

483

inhibiting matrix metalloproteinase-2/9 and urokinase-plasminogen activator through the

484

PI3K/Akt and ERK signaling pathways. J. Agric. Food Chem. 2010, 58, 9468-75.

485

41.

486

Sheen, L. Y. Antcin K, an Active Triterpenoid from the Fruiting Bodies of Basswood-

487

Cultivated Antrodia cinnamomea, Inhibits Metastasis via Suppression of Integrin-Mediated

488

Adhesion, Migration, and Invasion in Human Hepatoma Cells. J. Agric. Food. Chem. 2015,

489

63, 4561-9.

490

42.

491

Shih, Y. W. Nobiletin, a citrus flavonoid, suppresses invasion and migration involving

492

FAK/PI3K/Akt and small GTPase signals in human gastric adenocarcinoma AGS cells. Mol.

493

Cell. Biochem. 2011, 347, 103-15.

Kanegae, M. P.; Condino-Neto, A.; Pedroza, L. A.; de Almeida, A. C.; Rehder, J.; da

Houser, K. R.; Johnson, D. K.; Ishmael, F. T. Anti-inflammatory effects of

Woodhouse, E. C.; Chuaqui, R. F.; Liotta, L. A. General mechanisms of metastasis.

Huang, G. J.; Yang, C. M.; Chang, Y. S.; Amagaya, S.; Wang, H. C.; Hou, W. C.;

Huang, Y. L.; Chu, Y. L.; Ho, C. T.; Chung, J. G.; Lai, C. I.; Su, Y. C.; Kuo, Y. H.;

Lee, Y. C.; Cheng, T. H.; Lee, J. S.; Chen, J. H.; Liao, Y. C.; Fong, Y.; Wu, C. H.;


20

Page 21 of 31


494

43.

Xu, C. S.; Wang, Z. F.; Huang, X. D.; Dai, L. M.; Cao, C. J.; Li, Z. Q. Involvement of

495

ROS-alpha v beta 3 integrin-FAK/Pyk2 in the inhibitory effect of melatonin on U251 glioma

496

cell migration and invasion under hypoxia. J. Transl. Med. 2015, 13, 95.

497

44.

498

I.; Jeong, T. C.; Jeong, H. G. Suppression of EGF-induced tumor cell migration and matrix

499

metalloproteinase-9 expression by capsaicin via the inhibition of EGFR-mediated FAK/Akt,

500

PKC/Raf/ERK, p38 MAPK, and AP-1 signaling. Mol. Nutr. Food Res. 2011, 55, 594-605.

501

45.

502

MDA-MB-231 human breast cancer cells. J. Nutr. Biochem. 2008, 19, 313-9.

503

46.

504

human hepatocarcinoma cell invasion by 6-shogaol and 6-gingerol. Mol. Nutr. Food Res.

505

2012, 56, 1304-14.

506

47.

507

C.; Chang, W. C.; Chiu, T. P.; Wen, Z. H.; Fong, Y.; Chiu, C. C.; Chen, B. H. Feruloyl-L-

508

arabinose attenuates migration, invasion and production of reactive oxygen species in H1299

509

lung cancer cells. Food Chem. Toxicol. 2013, 58, 459-66.

Hwang, Y. P.; Yun, H. J.; Choi, J. H.; Han, E. H.; Kim, H. G.; Song, G. Y.; Kwon, K.

Lee, H. S.; Seo, E. Y.; Kang, N. E.; Kim, W. K. [6]-Gingerol inhibits metastasis of

Weng, C. J.; Chou, C. P.; Ho, C. T.; Yen, G. C. Molecular mechanism inhibiting

Fang, H. Y.; Wang, H. M.; Chang, K. F.; Hu, H. T.; Hwang, L. J.; Fu, T. F.; Lin, Y.

510 511 512 513 514 515 516 517 518


21


519

Page 22 of 31

Figure captions

520 521

Figure 1. Conversion of vanillin and apocynin to divanillin and diapocynin.

522 523

Figure 2. Inhibitory effect of divanillin, diapocynin, and their monomeric forms on HepG2

524

cell invasion. (A) The cells were treated with various concentrations of test compounds for 30

525

min and then allowed to invade in Matrigel-coated Transwell chambers for another 24 h. The

526

invaded cells were stained with crystal violet dye and counted. Cell viability after 24 h

527

treatment with test compounds was determined by the MTT assay. Data are presented as

528

mean ± SEM from three independent experiments. * (p < 0.05), ** (p < 0.01) and *** (p

Homodimers of Vanillin and Apocynin Decrease the Metastatic

Recommend Documents