Monascus Pigment Rubropunctatin: A Potential Dual Agent for Cancer

Mar 8, 2016 - It was suggested that rubropunctatin could be a promising natural dual anticancer agent for photodynamic therapy and chemotherapy...
0 downloads 0 Views 1MB Size
Subscriber access provided by Weizmann Institute of Science

Article

Monascus pigment rubropunctatin: a potential dual agent for cancer chemotherapy and phototherapy Yunquan Zheng, Yun Zhang, Deshan Chen, Haijun Chen, Ling Lin, Chengzhuo Zheng, and Yanghao Guo J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.5b05343 • Publication Date (Web): 08 Mar 2016 Downloaded from http://pubs.acs.org on March 10, 2016

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 33

Journal of Agricultural and Food Chemistry

1

Monascus pigment rubropunctatin: a potential dual agent for cancer

2

chemotherapy and phototherapy

3

Yunquan Zheng,*,†,§ Yun Zhang,†,§ Deshan Chen,† Haijun Chen,*,† Ling Lin,†

4

Chengzhuo Zheng,† Yanghao Guo§

5

6



College of Chemistry, Fuzhou University, 2 Xueyuan Road, Fuzhou 350116, China

7

§

Fujian Key Laboratory of Medical Instrument and Pharmaceutical Technology,

8

Fuzhou University, 523 Gongye Road, Fuzhou 350002, China

9

Corresponding authors:

10

* Yunquan Zheng, PhD

11

College of Chemistry

12

Fuzhou University

13

Fuzhou, Fujian 350116, China

14

Email: [email protected]

15

*Haijun Chen, PhD

16

College of Chemistry

17

Fuzhou University

18

Fuzhou, Fujian 350116, China

19

Email: [email protected]

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

20

ABSTRACT

21

The Monascus pigment, rubropunctatin, was extracted and purified from red mold

22

rice (RMR) and its cytotoxic activities against human cervical carcinoma HeLa cells

23

were studied under the conditions with or without light irradiation. The IC50 value of

24

rubropunctatin against HeLa cells in the dark was 93.71 ± 1.96 µM (24 h), while the

25

cytotoxic activity was enhanced more than 3 times (IC50 = 24.02 ± 2.17 µM) under

26

light irradiation(halogen lamp: 500 W, wavelength: 597-622 nm, fluence rate: 15 mW

27

cm-2, for 30 min). However the IC50 value of rubropunctatin against the immortalized

28

human cervical epithelial H8 cells was more than 300 µM even under light irradiation,

29

indicating that rubropunctatin has a favorable selectivity index (SI). Treatment of

30

HeLa cells with rubropunctatin in the dark or under light irradiation resulted in a dose

31

dependent apoptosis, as validated by the increase in the percentage of cells in sub-G1

32

phase and phosphatidylserine externalization, and the inductive effect on HeLa cell

33

apoptosis was boosted by the light irradiation. In addition, treatment with

34

rubropunctatin alone or under light irradiation was found to induce apoptosis in HeLa

35

cells via the mitochondrial pathway, including loss of mitochondrial membrane

36

potential, activation of caspase-3, -8 and -9, and increase of the level of intracellular

37

ROS. It was suggested that rubropunctatin could be a promising natural dual

38

anticancer agent for photodynamic therapy and chemotherapy.

39

KEYWORDS: Monascus, rubropunctatin, chemotherapy, phototherapy

40

ACS Paragon Plus Environment

Page 2 of 33

Page 3 of 33

Journal of Agricultural and Food Chemistry

41

INTRODUCTION

42

Cancer has become a significant public health problem due to its high rates of

43

morbidity and mortality. Recently, development of innovative anticancer drugs with

44

enhanced efficacy and improved selectivity is one of the most important works in

45

medicinal chemistry research communities. This paradigm has resulted in the

46

successful development of numerous anticancer agents. However, almost all kinds of

47

the existing chemotherapeutic drugs in the clinical application for cancer treatment

48

often result in therapeutic resistance and undesired side effects in all types of cancers.

49

In addition, it is reported that cancer therapy relying on a single therapeutic treatment

50

is not always reliable due to the complex network of cellular pathways.1 Therefore, it

51

is still a big challenge to find a suitable therapy for human cancer treatment.

52

To date, combination therapy has been considered as a promising strategy to take

53

the advantage of each treatment to minimize undesirable adverse effects and improve

54

therapeutic efficiency.2,

55

phototherapy has emerged as an effective strategy for cancer therapy.4-6 Phototherapy

56

also known as photodynamic therapy (PDT) is a well-established clinical cancer

57

treatment that involves a certain photosensitizer, light and molecular oxygen.7, 8 Upon

58

irradiation with the light of an appropriate wave-length, the excited photosensitizer

59

transfers energy from the ground state to the excited state to generate highly reactive

60

species, leading to irreversible damage of cancer cells. Recently, several

61

nanoparticle-based delivery systems including silica nanocages and lipid-polymers

3

In particular, the combination of chemotherapy and

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

62

have been developed to release the chemotherapeutic drug and photosensitizer

63

simultaneously in the tumour region to exert the synergistic anticancer effect.9-11

64

Although these important progresses have demonstrated the obvious potential both in

65

vitro and in vivo, there have been few report of the small organic molecule acting as

66

both chemotherapeutic agent and photosensitizer.7, 8, 12

67

Monascus is a versatile genus that can be used for the production of various

68

metabolites and is useful as food additives and pharmaceuticals. 13, 14 In our previous

69

work six pigment components were successfully separated from Monascus product,

70

which were two yellow pigments (monascin and ankaflavin), two orange pigments

71

(rubropunctatin and monascorubrin) and two red pigments (rubropunctatamine and

72

monascorubramine). The cytotoxicity of the Monascus pigments to various human

73

cancer cells (SH-SY5Y, HepG2, HT-29, BGC-823, AGS, and MKN45) was separately

74

evaluated. rubropunctatin showed the highest anticancer effect within the tested

75

compounds. The inhibition effect of rubropunctatin was higher than that of taxol on

76

the growth of the human gastric cancer cell SH-SY5Y (P < 0.05), BGC-823 (P yellow light > green light > blue light (Table 1 ).

247

Cytotoxicity of Rubropunctatin to HeLa Cells under Conditions with or without

248

Irradiation. To validate whether rubropunctatin could be used as a photosensitizer

249

against cancer cells, we investigated the cytotoxic effect of rubropunctatin on the

250

growth of HeLa cells under conditions with or without light irradiation.

251

rubropunctatin showed an obvious concentration-dependent inhibition effect on HeLa

252

cells from 3 to 120 µM under conditions either with or without light

ACS Paragon Plus Environment

Page 12 of 33

Page 13 of 33

Journal of Agricultural and Food Chemistry

253

irradiation. rubropunctatin inhibited the proliferation of HeLa cells in the dark with an

254

IC50 of 93.71 ± 1.96 µM after 24 h incubation. The experimental data indicated that

255

rubropunctatin alone has a modest inhibitory effect on HeLa cells. In the presence of

256

light irradiation, rubropunctatin displayed a remarkable growth inhibitory effect

257

against HeLa cells with an IC50 of 24.02 ± 2.17 µM after 24 h incubation. It was

258

suggested that rubropunctatin could be used as a promising natural dual anticancer

259

agent for photodynamic therapy and chemotherapy.

260

A time-course study revealed that rubropunctatin in the dark displayed no toxic

261

effect on HeLa cells at the first 4 hours however it obviously inhibited the

262

proliferation of HeLa cells after 12 h or 24 h incubation (Table 2). Rubropunctatin

263

decreased the viability of HeLa cells in a time-dependent manner under conditions

264

with or without light irradiation.

265

As shown in Table 2, Taxol was used as a control and its cytotoxicity against Hela

266

cells was determined. Under conditions without irradiation, Taxol showed a good

267

inhibition effect on the growth of Hela cells with IC50 of 73.31±2.23µmol/L at 12h

268

and 44.32±3.84µmol/L at 24h. However, no obvious change was observed, compared

269

with the determined data in the absence of light irradiation with those in the presence

270

of light irradiation, IC50 of 76.86±2.54µmol/L at 12h and 42.71±4.31µmol/L at 24h.

271

It was notable that under conditions with light irradiation, the inhibition effect on

272

the treated Hela cells with rubropunctatin was higher than that with taxol. In addition,

273

rubropunctatin was basically no-cytotoxic to the immortalized human cervical

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

274

epithelial H8 cells with the IC50 value greater than 300 µM (at 24h) in the dark or

275

under light irradiation, indicating that rubropunctatin has a favorable selectivity index

276

(SI).

277

Apoptosis of HeLa Cells Induced by Rubropunctatin under Conditions with or

278

without Light Irradiation. After being treated separately with different

279

concentrations of rubropunctatin for 24 h, the AO/EB staining of HeLa cells was

280

performed to evaluate the mode of cell death under the conditions with or without

281

light irradiation. The cell morphology was observed under the fluorescence

282

microscope. Figure 3 showed clear morphological changes in the nucleolus, internal

283

organelles and plasma membrane integrity caused by rubropunctatin in a

284

concentration-dependent manner. In the presence or absence of light irradiation, the

285

rubropunctatin untreated HeLa cells showed uniform green fluorescence with normal

286

morphology, indicating that light irradiation alone did not change morphology of the

287

cells. After rubropunctatin treatment without or with light irradiation, extensive

288

nuclear margination accompanied by chromatin condensation and fragmentation,

289

indicative of apoptotic cell death, was observed in the treated cells.23, 24 With the

290

increase of rubropunctatin concentration, the marked nuclear condensation, membrane

291

breakage, nuclear fragmentation and apoptotic bodies became visibly dominant and

292

fluorescence turned into orange, indicating cell death.

293

HeLa cells which were incubated with 30 µM rubropunctatin in the absence of light

294

irradiation showed green fluorescence. It demonstrated that the cell membranes were

ACS Paragon Plus Environment

Page 14 of 33

Page 15 of 33

Journal of Agricultural and Food Chemistry

295

normally integrated and kept EB out of the cells. When treated with the same

296

concentration of rubropunctatin in the presence of light irradiation, the fluorescence

297

turned into orange and showed that the membranes were impaired. The results of

298

AO/EB nuclear staining indicated remarkable induction of apoptosis in HeLa cells by

299

rubropunctatin under the conditions with light irradiation.

300

Cell Cycle Analysis. To characterize cell death induced by rubropunctatin, cell cycle

301

analysis was performed by staining the cells with PI (Table 3). HeLa cells were

302

treated separately with different concentrations of rubropunctatin (0, 3, 30, 60, 90 and

303

120 µM) under the conditions with or without light irradiation. The data showed that

304

treatment with rubropunctatin increased the fraction of cells in the sub-G1 phase (an

305

apoptotic phenomenon) in a dose-dependent manner under light irradiation, while

306

treatment with rubropunctatin in the dark only enhanced the fraction of cells in the

307

sub-G1 phase at the high concentration. However, no arrest at any phase of the cell

308

cycle was found. It was hypothesized that rubropunctatin might inhibit cell growth of

309

the HeLa cells through induction of apoptosis, and the affection was enhanced by

310

light irradiation.

311

Apoptotic Analysis of HeLa Cells treated with Rubropunctatin under the

312

Conditions with or without Light Irradiation. The cytotoxic effect of chemo-

313

photodynamic treatment on HeLa cells was further quantified by flow cytometry.

314

HeLa cells were double-labelled by Annexin-V/PI after they were treated with

315

different concentrations of rubropunctatin under the conditions with or without light

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

316

irradiation. The Annexin-V and PI positive cells were defined as late

317

apoptotic/necrotic stage. As shown in Figure 4, the untreated cells were primarily

318

Annexin-V and PI negative, indicating that they were viable and not undergoing

319

apoptosis either in the absence or presence of light irradiation. After treatment with

320

rubropunctatin in the dark or under light irradiation, rubropunctatin produced a

321

dose-dependent increase in the HeLa necrotic population and a decrease in viable

322

population, and induced HeLa cells from early apoptotic stage into late

323

apoptotic/necrotic stage. Compared with the treatment in the dark, the results showed

324

that rubropunctatin plus light marginally induces cell late apoptosis/necrosis (such as

325

38.6% vs 30.2% at 120 µM), indicating that the cytotoxic effect of rubropunctatin on

326

HeLa cells was boosted by the light irradiation.

327

Rubropunctatin-induced Loss of ∆Ψm in HeLa Cells under the Conditions with

328

or without Light Irradiation. The loss of mitochondrial membrane potential (∆Ψm)

329

is regarded as a limiting factor in the induction of apoptosis by the intrinsic pathway.25

330

To determine whether rubropunctatin induced damage of the mitochondrial function

331

with light irradiation, we determined ∆Ψm by using JC-1 staining. The absolute

332

red/green JC-1 intensity ratio (FL1/FL2) was measured.

333

quantitative analysis of mitochondrial membrane depolarization by flow cytometry

334

showed that the cellular ∆Ψm was decreased after exposure of HeLa cells to

335

rubropunctatin under the conditions with or without light irradiation. The negative

336

control HeLa cells were with higher potentials and theratio of red/green JC-1

337

fluorescence was above 1.3. In the positive control, CCCP was used as an inducer to

ACS Paragon Plus Environment

As shown in Table 4,

Page 16 of 33

Page 17 of 33

Journal of Agricultural and Food Chemistry

338

decrease the mitochondrial membrane potential and the determined FL1/FL2 was 0.87.

339

After HeLa cells were exposed to 30 or 60 µM rubropunctatin for 24 h, it was noted

340

that ∆Ψm did not change ether in the dark or under light irradiation, indicating that the

341

loss of ∆Ψm possibly reached a maximum at 30 µM. These results indicated that

342

rubropunctatin induced apoptosis via the mitochondrial pathway. The cytotoxic effect

343

of rubropunctatin on HeLa cells was boosted by the light irradiation, but

344

mitochondrial membrane potential did not change.

345

Induction of the Activation of Caspase-3, -8 and -9 by Rubropunctatin. Treatment

346

of HeLa cells with rubropunctatin (30 and 60 µM) resulted in a dose-dependent

347

increase in the activities of caspase-3, -8 and -9 either in the dark or under light

348

irradiation (Figure 5). Compared with the treatment in the dark, the data under the

349

conditions with light irradiation showed an obvious increase of the activity of

350

caspase-3, -8 and -9, further indicating that the combination of rubropunctatin

351

treatment and light irradiation was more effective than treatment alone with the drug

352

to induce cell apoptosis.

353

The mitochondrial pathway plays an essential role for cell apoptosis, in which

354

caspase-3, -8 and -9 are involved. Our experimental data demonstrated that

355

rubropunctatin treatment led to the activation of caspase-3, -8 and -9. These results

356

indicated that rubropunctatin induced cell apoptosis via the mitochondrial pathway.

357

Production of Cellular ROS induced by Rubropunctatin under Conditions with

358

or without Light Irradiation. The interaction of the photosensitisers with cancer

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

359

cells can induce oxidative stress by enhancing the production of intracellular ROS

360

over the cellular antioxidant defenses. To investigate the effect of rubropunctatin on

361

the production of intracellular ROS, the treated cells were quantified by determining

362

the percentage of cells with increased green fluorescence in a flow cytometer. Under

363

the conditions without light irradiation the determined ROS levels produced in the

364

Hela cells treated by rubropunctatin with lower concentrations were in the same order

365

of magnitude with the blank group of rubropunctatin untreated cells. It is evident from

366

the flow cytometric analysis that the treatment of rubropunctatin raised the level of

367

intracellular ROS only at the high concentration of 90µM in the absence of irradiation.

368

However, the intracellular ROS level in presence of light irradiation increased even at

369

the lower rubropunctatin concentrations, which was toxic enough to augment the

370

apoptotic cell death by damaging mitochondrial membrane integrity. Table 5 showed

371

an obvious elevation of the ROS production in the rubropunctatin treated cells under

372

the conditions with light irradiation compared to without irradiation. The experimental

373

data of the intracellular ROS level treated by rubropunctatin under conditions with

374

light irradiation or without light irradiation were consistent with the reported data

375

regarding the cytotoxic activities against HeLa cells mentioned above.

376

In this work, we found the photochemical properties of rubropunctatin and reported

377

the fact that light irradiation with wavelength 597-622nm remarkably strengthened its

378

cytotoxic activities against human cervical carcinoma HeLa cells. The cytotoxicity of

379

rubropunctatin on various human cervical carcinoma cells (Siha, Caski, C33A) was

380

also systematically evaluated in our experiments, and the tendency of the cytotoxicity

ACS Paragon Plus Environment

Page 18 of 33

Page 19 of 33

Journal of Agricultural and Food Chemistry

381

under the conditions with irradiation over that without irradiation was in the same

382

manner as Hela cells. Photodynamic therapy is believed to cause cell damage via the

383

production of ROS and subsequently to induce apoptotic signaling via the

384

mitochondrial pathway. Rubropunctatin increased intracellular ROS generation and

385

decreased mitochondrial membrane potential. These results suggest that the anticancer

386

effect of rubropunctatin was probably due to the modulation of cell signaling and

387

intracellular ROS generation. The treatment of rubropunctatin under the conditions

388

with light irradiation promoted the induction of Hela cells into late apoptosis/necrosis

389

phase. Activation of caspase 8 and 9 in the upstream resulted in the activation of

390

caspase 3 in the downstream and in the end speeded up cell apoptosis. In order to

391

develop anticancer effects of rubropunctatin, it is essential to further understand the

392

precise mechanism of cytotoxic activities of rubropunctatin in the presence of light

393

irradiation.

394

The photochemical reaction of rubropunctain was studied by HPLC-MS (data not

395

shown).

Rubropunctain

is a

natural azaphilone compound

396

microbiological metabolite, which has a typical structure with multiple rings

397

involving multiple conjugated double bonds and mixed oxygen atoms. After light

398

irradiation, part of rubropunctain was degradated and some new compounds with

399

higher polarity were produced. The hydroxyl free radicals and hydrogen free radiacals

400

produced from RH (hydrogen donor) under the conditions with light irradiation could

401

easily attack the conjugating double bands in the rubropunctain molaculars. When

402

rubropunctain in the water solution was radiated with light, colour fading was

ACS Paragon Plus Environment

isolated

from

Journal of Agricultural and Food Chemistry

Page 20 of 33

403

observed, which was due to the conjugate structure’s damage. It is required to further

404

explore the photochemical reaction mechanism of rubropunctain in the presence of

405

light irradiation.

406

AUTHOR INFORMATION

407

Corresponding Authors

408

*Fax:

409

[email protected] (Y. Zheng)

410

Fax: +86-591-22866234 ; Tel: +86-591-22866227; E-mail: [email protected] (H.

411

Chen)

412

Notes

413

The authors declare no competing financial interest.

414

Acknowledgment

415

This work was supported by National Natural Science Foundation of China (No.

416

J1103303),

417

2012J05155), Marine Public Welfare Research Project of China (201205022), and the

418

Technology Development Foundation of Fuzhou University (Project Numbers

419

2011-XY-7 and 2013-XQ-9).

420

REFERENCES

421

1.

+86-591-83720772;

Tel:

Natural Science Foundation

+86-591-83720772;

of Fujian Province

of

E-mail:

China

Lane, D., Designer combination therapy for cancer. Nature biotechnology 2006, 24, 163-4.

ACS Paragon Plus Environment

(No.

Page 21 of 33

Journal of Agricultural and Food Chemistry

422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465

2.

Levinson, A. D., Cancer therapy reform. Science 2010, 328, 137.

3.

Woodcock, J.; Griffin, J. P.; Behrman, R. E., Development of novel combination therapies. The

New England journal of medicine 2011, 364, 985-7. 4.

Nonaka, Y.; Nanashima, A.; Nonaka, T.; Uehara, M.; Isomoto, H.; Abo, T.; Nagayasu, T., Synergic

effect of photodynamic therapy using talaporfin sodium with conventional anticancer chemotherapy for the treatment of bile duct carcinoma. The Journal of surgical research 2013, 181, 234-41. 5.

Peterson, C. M.; Shiah, J. G.; Sun, Y.; Kopeckova, P.; Minko, T.; Straight, R. C.; Kopecek, J.,

HPMA copolymer delivery of chemotherapy and photodynamic therapy in ovarian cancer. Advances in experimental medicine and biology 2003, 519, 101-23. 6.

Diez, B.; Ernst, G.; Teijo, M. J.; Batlle, A.; Hajos, S.; Fukuda, H., Combined chemotherapy and

ALA-based photodynamic therapy in leukemic murine cells. Leukemia research 2012, 36, 1179-84. 7.

Celli, J. P.; Spring, B. Q.; Rizvi, I.; Evans, C. L.; Samkoe, K. S.; Verma, S.; Pogue, B. W.; Hasan,

T., Imaging and photodynamic therapy: mechanisms, monitoring, and optimization. Chemical reviews 2010, 110, 2795-838. 8.

Lovell, J. F.; Liu, T. W.; Chen, J.; Zheng, G., Activatable photosensitizers for imaging and therapy.

Chemical reviews 2010, 110, 2839-57. 9.

Wang, T.; Zhang, L.; Su, Z.; Wang, C.; Liao, Y.; Fu, Q., Multifunctional hollow mesoporous silica

nanocages for cancer cell detection and the combined chemotherapy and photodynamic therapy. ACS applied materials & interfaces 2011, 3, 2479-86. 10. Zheng, M.; Yue, C.; Ma, Y.; Gong, P.; Zhao, P.; Zheng, C.; Sheng, Z.; Zhang, P.; Wang, Z.; Cai, L., Single-step assembly of DOX/ICG loaded lipid--polymer nanoparticles for highly effective chemo-photothermal combination therapy. ACS nano 2013, 7, 2056-67. 11. Ren, H.; Wu, Y.; Li, Y.; Cao, W.; Sun, Z.; Xu, H.; Zhang, X., Visible-Light-Induced Disruption of Diselenide-Containing

Layer-by-Layer

Films:

Toward

Combination

of

Chemotherapy

and

Photodynamic Therapy. Small 2013, 9, 3981-6. 12. Chen, H.; Zhou, X.; Gao, Y.; Zheng, B.; Tang, F.; Huang, J., Recent progress in development of new sonosensitizers for sonodynamic cancer therapy. Drug discovery today 2014, 19, 502-9. 13. Osmanova, N.; Schultze, W.; Ayoub, N., Azaphilones: a class of fungal metabolites with diverse biological activities. Phytochem Rev 2010, 9, 315-342 14. Gao, J. M.; Yang, S. X.; Qin, J. C., Azaphilones: chemistry and biology. Chemical reviews 2013, 113, 4755-811. 15. Zheng, Y.; Xin, Y.; Shi, X.; Guo, Y., Cytotoxicity of Monascus pigments and their derivatives to human cancer cells. Journal of agricultural and food chemistry 2010, 58, 9523-8. 16. Zheng, Y.; Xin, Y.; Shi, X.; Guo, Y., Anti-cancer effect of rubropunctatin against human gastric carcinoma cells BGC-823. Applied microbiology and biotechnology 2010, 88, 1169-77. 17. Wild, D.; Toth, G.; Humpf, H. U., New monascus metabolites with a pyridine structure in red fermented rice. Journal of agricultural and food chemistry 2003, 51, 5493-6. 18. Su, N. W.; Lin, Y. L.; Lee, M. H.; Ho, C. Y., Ankaflavin from Monascus-fermented red rice exhibits selective cytotoxic effect and induces cell death on Hep G2 cells. Journal of agricultural and food chemistry 2005, 53, 1949-54. 19. Hong, M. Y.; Seeram, N. P.; Zhang, Y.; Heber, D., Anticancer effects of Chinese red yeast rice versus monacolin K alone on colon cancer cells. The Journal of nutritional biochemistry 2008, 19, 448-58. 20. Ho, B. Y.; Pan, T. M., The Monascus metabolite monacolin K reduces tumor progression and

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

466 467 468 469 470 471 472 473 474 475 476 477 478 479

metastasis of Lewis lung carcinoma cells. Journal of agricultural and food chemistry 2009, 57, 8258-65. 21. Hsu, Y. W.; Hsu, L. C.; Liang, Y. H.; Kuo, Y. H.; Pan, T. M., Monaphilones A-C, three new antiproliferative azaphilone derivatives from Monascus purpureus NTU 568. Journal of agricultural and food chemistry 2010, 58, 8211-6. 22. Zheng, Y.; Xin, Y.; Guo, Y., Study on the fingerprint profile of Monascus products with HPLC-FD, PAD and MS. Food Chemistry 2009, 113, 705-711. 23. Allen, R. T.; Hunter, W. J., 3rd; Agrawal, D. K., Morphological and biochemical characterization and analysis of apoptosis. Journal of pharmacological and toxicological methods 1997, 37, 215-28. 24. Rello, S.; Stockert, J. C.; Moreno, V.; Gamez, A.; Pacheco, M.; Juarranz, A.; Canete, M.; Villanueva, A., Morphological criteria to distinguish cell death induced by apoptotic and necrotic treatments. Apoptosis : an international journal on programmed cell death 2005, 10, 201-8. 25. Kim, R.; Emi, M.; Tanabe, K., Role of mitochondria as the gardens of cell death. Cancer chemotherapy and pharmacology 2006, 57, 545-53.

480

481

ACS Paragon Plus Environment

Page 22 of 33

Page 23 of 33

Journal of Agricultural and Food Chemistry

482 483

Table 1. The influence of light irradiation with different wavelengths on the light chemical reaction of rubropunctatin Irradiation condition

wavelength

Degradation Rate of rubropunctain, %

red light

622-770nm

64.5

orange light

597-622nm

68.8

yellow light

577-597nm

58.4

green light

492-577nm

57.2

blue light

455-492nm

16.3

484

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

485

Page 24 of 33

Table 2. Cytotoxicity of rubropunctatin and Taxol on HeLa and H8 cells

Cells treated with rubropunctatin for different time (h)

IC50 of rubropunctatin (µmol/L)

IC50 of Taxol (µmol/L)

Without Light Irradiation

With Light Irradiation

Without Light Irradiation

With Light Irradiation

HeLa (4h)

>1000

>1000

>1000

>1000

HeLa (12h)

146.61±2.45

44.19±2.86

73.31±2.23

76.86±2.54

HeLa (24h)

93.71±1.96

24.02±2.17

44.32±3.84

42.71±4.31

H8 (24h)

>300

>300

120.83±4.52

124.39±5.03

486

ACS Paragon Plus Environment

Page 25 of 33

Journal of Agricultural and Food Chemistry

Table 3. DNA flow cytometric analysis of cell cycle distribution.a

487

Condition without light irradiation with light irradiation

Cell

Concentration (µM) Control

3

30

60

90

Sub-G1

1.64±0.02

1.98±0.04*

1.91±0.01*

1.96±0.03*

2.6±0.03**

6.4±0.01**

G0/G1

63.95±5.21

63.83±3.43

65.82±5.42

61.26±6.54

59.1±7.54*

60.95±3.54*

S

9.94±0.89

9.22±0.45

9.88±0.52

8.92±0.23*

9.30±0.53

10.17±0.48

Cycle

120

G2/M

24.47±1.23

24.97±1.14

22.39±1.42

27.86±0.95*

29.00±0.92*

22.48±1.42*

Sub-G1

2.11±0.03

3.25±0.01**

5.03±0.03**

8.21±0.06**

12.2±1.03**

14.09±1.40**

G0/G1

63.79±5.06

63.43±3.40

57.98±5.03*

56.2±5.04**

52.1±4.05**

47.36±6.95**

S

10.66±1.03

10.67±1.34

11.33±2.01

10.91±1.24

10.23±0.89

9.3±0.98*

G2/M

23.44±1.04

22.65±1.93

25.66±1.02*

24.68±1.29

25.47±2.01*

29.25±2.89**

488

a

489

the respective controls for each experimental test condition was assessed using Student’s unpaired

490

t test, with *p < 0.05 or **p < 0.01 being regarded as statistically significant.

Each value represents the mean ± SD of three separate experiments. A significant difference from

491

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

492

Table 4. Effects of rubropunctatin on mitochondrial membrane potential (∆Ψm) of

493

Hela cells without or with light irradiationa. Condition

Concentration(µM) b

without light irradiation with light irradiation

CCCP control 30 60 CCCPb control 30 60

FL2/FL1 0.87±0.09** 1.37±0.12 0.86±0.05** 0.87±0.04** 0.78±0.02** 1.41±0.11 0.94±0.06** 0.94±0.05**

494

a

495

the respective controls for each experimental test condition was assessed using Student’s unpaired

496

t test, with *p