||The Apoptotic Effect of Arsenic Compounds on MA-10 Mouse Leydig Tumor Cells
||Institute of Cell Biology and Anatomy
Leydig tumor cell
Bcl-2 family proteins
Reactive oxygen species (ROS)
砷是一種於大自然常見的環境毒物，研究顯示長期暴露之下會對人體造成毒害，嚴重者會造成神經病變、心血管疾病、糖尿病、高血壓…等，然而，近來有學者利用三氧化二砷（As2O3；俗稱砒霜）治療罹患急性前骨髓性白血病（Acute promyelocytic leukemia; APL）的病人，在臨床試驗上發現其病情能得到緩解。同時，在體外研究發現三氧化二砷會誘導不成熟的白血球細胞走向細胞凋亡。而根據統計，男性癌症中，睪丸癌發生率有逐年增加的趨勢，為提高患者的治療品質，因而希望能尋求更好的治療方針。由於過去研究證實砷的抗癌效用，因此進一步想探討砷是否對萊氏細胞腫瘤有相似的抗癌效果。我們利用MA-10細胞株（小鼠萊氏腫瘤細胞）處理不同濃度的亞砷酸鈉（Sodium arsenite, NaAsO2）及二甲基砷酸（(CH3)2AsO2H, DMA）來探討其抗癌效用及其分子機制。研究發現在100 μM亞砷酸鈉作用三小時以及1 mM二甲基砷酸作用二十四小時以後，MA-10細胞出現許多典型細胞凋亡（apoptosis）的特徵，例如：細胞鼓起（cell rounded up）以及細胞膜發泡（membrane blebbing）等現象；此外，透過細胞存活率分析（MTT viability test）發現處理10 μM亞砷酸鈉細胞以及10 mM二甲基砷酸，都會造成細胞存活率顯著的下降（p<0.05）；利用流式細胞儀分析，可觀察到subG1 以及G2/M期的顯著上升（p<0.05）；透過細胞雙染試驗，更證實砷化合物（亞砷酸鈉及二甲基砷酸）確實會誘導MA-10細胞株走向凋亡。進一步，砷化合物也會促使硫胱氨酸蛋白酶（caspase-8, -9 and -3）的活化以及聚（腺苷二磷酸-核糖）多聚酶（PARP）的裂解；利用硫胱氨酸蛋白酶抑制劑（caspase inhibitor）會阻斷由砷化合物所誘導的硫胱氨酸蛋白酶（caspase-8, -9 and -3）活化。值得注意的是只有亞砷酸鈉會顯著增加Fas ligand（FasL）的蛋白質表現而非二甲基砷酸。另外，亞砷酸鈉和二甲基砷酸都會造成Bax移位（Bax translocation）、Bid的切截（Bid truncation）、cytochrome C的釋放（cytochrome C release）以及活性氧化物（reactive oxygen species, ROS）的增加。ERK1/2, JNK, p38 MAPK訊息傳遞路徑的活化也參與在砷化合物（亞砷酸鈉及二甲基砷酸）所誘導的細胞凋亡當中；然而，砷化合物（亞砷酸鈉及二甲基砷酸）會降低Akt的磷酸化並且也會影響Akt的蛋白質表現。根據以上的實驗結果發現砷化合物（亞砷酸鈉及二甲基砷酸）會使得MA-10細胞株活化外在死亡受體細胞凋亡路徑（extrinsic; death receptor pathway）以及內在粒腺體細胞凋亡路徑（intrinsic; mitochondrial pathway）以及改變MAPK和Akt訊息傳遞路徑的活性，而導致細胞凋亡。此外，實驗結果也發現亞砷酸鈉比二甲基砷酸在MA-10細胞株之中具有較高的療效。
Arsenic is an environmental toxicant. The research has shown that long term arsenic exposure can be harmful to human body, and has been associated with some chronic diseases. However, some researchers surprisingly found that arsenic trioxide showed the good therapeutic effect on acute promyelocytic leukemia (APL) patients, and in vitro studies indicated that arsenics could induce APL cell apoptosis. Because of increasing incident rate of the testicular cancer, we assumed whether arsenics might show the same apoptotic effect on testicular cancer cells. To test our hypothesis, we used MA-10 cells, a mouse Leydig tumor cell line, and treated with different concentrations of sodium arsenite and dimethylarsenic acid to determine the apoptotic effect and mechanism. Our data showed that MA-10 cells appeared rounded-up and exhibited membrane blebbings after treatment with 100 μM sodium arsenite for 3 h or 1 mM dimethylarsenic acid for 24 h. Besides, MTT viability test demonstrated that MA-10 cells appeared apoptotic after treatment with 10 μM sodium arsenite for 6 h or 10 mM dimethylarsenic acid for 24 h. In flow cytometry analysis, both sodium arsenite and dimethylarsenic acid significantly increased the ratio of subG1 and G2/M phases (p<0.05). Annexin V/PI double staining study further demonstrated that arsenic compounds did significantly induce MA-10 cell apoptosis (p<0.05). Moreover, the arsenic-induced cell apoptosis was accompanied by the upregulation of cleaved caspase-8, -9, -3 and PARP proteins, and the caspase inhibitor reversed caspase-8, -9 and -3 cleavages in MA-10 cells. Interesting, the expression of FasL could be upregulated by sodium arsenite but not dimethylarsenic acid. Besides, Bax translocation, Bid truncation, cytochrome C release and elevation of ROS generation were also involved in arsenic-induced cell apoptosis. Furthermore, the activation of ERK1/2, JNK, p38 MAPK pathway could be induced by both sodium arsenite and dimethylarsenic acid in MA-10 cells. In addition, arsenic compounds decreased the expression and phosphorylation of Akt protein. In conclusion, arsenic compounds could induce cell apoptosis in MA-10 cells through the activation of intrinsic and extrinsic caspase cascades and the modulation of MAPK and Akt pathways, and sodium arsenite had higher efficacy than dimethylarsenic acid.
TABLE OF CONTENTS.........................................VI
LIST OF FIGURES.........................................VIII
MATERIALS AND METHODS
MTT Viability Test.........................................8
Cell Cycle Analysis........................................9
Annexin V/PI Double Staining Assay.........................9
Protein Extraction and Western Blotting Analysis..........10
Mitochondrial Protein Isolation...........................11
The Measurement of Intracellular ROS Generation...........11
The morphological changes of MA-10 cells after treatment with arsenic compounds....................................13
Arsenic compounds decreased MA-10 cell viability in time- and dose-dependent manners................................13
Arsenic compounds induced apoptosis in MA-10 cells........14
Arsenic-induced MA-10 cell apoptosis was mediated by caspase cascade...................................................15
Caspase inhibitor reversed arsenic-induced MA-10 cell apoptosis.................................................16
The different effects of arsenic compounds on the expression of Fas ligand.............................................17
The release of cytochrome C and translocation of Bcl-2 family proteins in arsenic-induced MA-10 cell apoptosis...17
Long-term arsenic exposure induced activation of MAPK pathways (ERK1/2, JNK and p38) ...........................19
Arsenic compounds decreased the phosphorylation and the expression of Akt protein.................................19
Arsenic compounds induced ROS generation during MA-10 cell apoptosis.................................................20
Adachi, T, Kar, S, Wang, M and Carr, BI. Transient and sustained ERK phosphorylation and nuclear translocation in growth control. Journal of Cellular Physiology. 192: 151-159, 2002.
Al-Agha, OM and Axiotis, CA. An in-depth look at Leydig cell tumor of the testis. Archives of Pathology and Laboratory Medicine. 131: 311-317, 2007.
Antonsson, B, Montessuit, S, Sanchez, B and Martinou, JC. Bax is present as a high molecular weight oligomer/complex in the mitochondrial membrane of apoptotic cells. Journal of Biological Chemistry. 276: 11615-11623, 2001.
Ashkenazi, A and Dixit, VM. Death receptors: signaling and modulation. Science. 281: 1305-1308, 1998.
Barchowsky, A, Klei, LR, Dudek, EJ, Swartz, HM and James, PE. Stimulation of reactive oxygen, but not reactive nitrogen species, in vascular endothelial cells exposed to low levels of arsenite. Free Radical Biology and Medicine. 27: 1405-1412, 1999.
Behrend, L, Henderson, G and Zwacka, RM. Reactive oxygen species in oncogenic transformation. Biochemical Society Transactions. 31: 1441-1444, 2003.
Bertram, KA, Bratloff, B, Hodges, GF and Davidson, H. Treatment of malignant Leydig cell tumor. Cancer. 68: 2324-2329, 1991.
Billen, LP, Shamas-Din, A and Andrews, DW. Bid: a Bax-like BH3 protein. Oncogene. 27: S93-S104, 2008.
Boonstra, J and Post, JA. Molecular events associated with reactive oxygen species and cell cycle progression in mammalian cells. Gene. 337: 1-13, 2004.
Boyer, A, Paquet, M, Lague, MN, Hermo, L and Boerboom, D. Dysregulation of WNT/CTNNB1 and PI3K/AKT signaling in testicular stromal cells causes granulosa cell tumor of the testis. Carcinogenesis. 30: 869-878, 2009.
Cardone, MH, Roy, N, Stennicke, HR, Salvesen, GS, Franke, TF, Stanbridge, E, Frisch, S and Reed, JC. Regulation of cell death protease caspase-9 by phosphorylation. Science. 282: 1318-1321, 1998.
Chen, CH, Wang, WJ, Kuo, JC, Tsai, HC, Lin, JR, Chang, ZF and Chen, RH. Bidirectional signals transduced by DAPK-ERK interaction promote the apoptotic effect of DAPK. EMBO Journal. 24: 294-304, 2005.
Chen, F, Castranova, V, Li, Z, Karin, M and Shi, X. Inhibitor of nuclear factor kappaB kinase deficiency enhances oxidative stress and prolongs c-Jun NH2-terminal kinase activation induced by arsenic. Cancer Research. 63: 7689-7693, 2003.
Chen, GQ, Shi, XG, Tang, W, Xiong, SM, Zhu, J, Cai, X, Han, ZG, Ni, JH, Shi, GY, Jia, PM, Liu, MM, He, KL, Niu, C, Ma, J, Zhang, P, Zhang, TD, Paul, P, Naoe, T, Kitamura, K, Miller, W, Waxman, S, Wang, ZY, de The, H, Chen, S-J and Chen, Z. Use of arsenic trioxide (As2O3) in the treatment of acute promyelocytic leukemia (APL): I. As2O3 exerts dose-dependent dual effects on APL cells. Blood. 89: 3345-3353, 1997.
Chen, YR, Wang, X, Templeton, D, Davis, RJ and Tan, TH. The role of c-Jun N-terminal kinase (JNK) in apoptosis induced by ultraviolet C and gamma radiation. Duration of JNK activation may determine cell death and proliferation. Journal of Biological Chemistry. 271: 31929-31936, 1996.
Chipuk, JE and Green, DR. How do BCL-2 proteins induce mitochondrial outer membrane permeabilization? Trends in Cell Biology. 18: 157-164, 2008.
Chipuk, JE, Moldoveanu, T, Llambi, F, Parsons, MJ and Green, DR. The BCL-2 family reunion. Molecular Cell. 37: 299-310, 2010.
Cook, JA, Gius, D, Wink, DA, Krishna, MC, Russo, A and Mitchell, JB. Oxidative stress, redox, and the tumor microenvironment. Seminars in Radiation Oncology. 14: 259-266, 2004.
Cory, S and Adams, JM. The Bcl2 family: regulators of the cellular life-or-death switch. Nature Reviews Cancer. 2: 647-656, 2002.
Das, J, Ghosh, J, Manna, P, Sinha, M and Sil, PC. Taurine protects rat testes against NaAsO2-induced oxidative stress and apoptosis via mitochondrial dependent and independent pathways. Toxicology Letters. 187: 201-210, 2009.
Datta, SR, Dudek, H, Tao, X, Masters, S, Fu, H, Gotoh, Y and Greenberg, ME. AKT phosphorylation of BAD couples survival signals to the cell-intrinsic death machinery. Cell. 91: 231-241, 1997.
Diepart, C, Karroum, O, Magat, J, Feron, O, Verrax, J, Calderon, PB, Gregoire, V, Leveque, P, Stockis, J, Dauguet, N, Jordan, BF and Gallez, B. Arsenic trioxide treatment decreases the oxygen consumption rate of tumor cells and radiosensitizes solid tumors. Cancer Research. 72: 482-490, 2012.
Dilda, PJ and Hogg, PJ. Arsenical-based cancer drugs. Cancer Treatment Reviews. 33: 542-564, 2007.
DiPaola, RS. To arrest or not to G2-M cell-cycle arrest. Clinical Cancer Research. 8: 3311-3314, 2002.
Eguchi, R, Fujimori, Y, Takeda, H, Tabata, C, Ohta, T, Kuribayashi, K, Fukuoka, K and Nakano, T. Arsenic trioxide induces apoptosis through JNK and ERK in human mesothelioma cells. Journal of Cellular Physiology. 226: 762-768, 2011.
Eruslanov, E and Kusmartsev, S. Identification of ROS using oxidized DCFDA and flow-cytometry. Methods in Molecular Biology. 594: 57-72, 2010.
Friesen, C, Herr, I, Krammer, PH and Debatin, KM. Involvement of the CD95 (APO-1/FAS) receptor/ligand system in drug-induced apoptosis in leukemia cells. Nature Medicine. 2: 574-577, 1996.
Green, LM, Reade, JL and Ware, CF. Rapid colorimetric assay for cell viability: application to the quantitation of cytotoxic and growth inhibitory lymphokines. Journal of Immunological Methods. 70: 257-268, 1984.
Hayashi, T, Hideshima, T, Akiyama, M, Richardson, P, Schlossman, RL, Chauhan, D, Munshi, NC, Waxman, S and Anderson, KC. Arsenic trioxide inhibits growth of human multiple myeloma cells in the bone marrow microenvironment Molecular Cancer Therapeutics. 1: 851-860, 2002.
Hoffman, RD and Lane, MD. Iodophenylarsine oxide and arsenical affinity chromatography: new probes for dithiol proteins. Application to tubulins and to components of the insulin receptor-glucose transporter signal transduction pathway. Journal of Biological Chemistry. 267: 14005-14011, 1992.
Huang, DC and Strasser, A. BH3-Only proteins-essential initiators of apoptotic cell death. Cell. 103: 839-842, 2000.
Huang, P and Oliff, A. Signaling pathways in apoptosis as potential targets for cancer therapy. Trends in Cell Biology. 11: 343-348, 2001.
Huyghe, E, Matsuda, T and Thonneau, P. Increasing incidence of testicular cancer worldwide: a review. Journal of Urology. 170: 5-11, 2003.
Iwama, K, Nakajo, S, Aiuchi, T and Nakaya, K. Apoptosis induced by arsenic trioxide in leukemia U937 cells is dependent on activation of p38, inactivation of ERK and the Ca2+-dependent production of superoxide. International Journal of Cancer. 92: 518-526, 2001.
Iyoda, K, Sasaki, Y, Horimoto, M, Toyama, T, Yakushijin, T, Sakakibara, M, Takehara, T, Fujimoto, J, Hori, M, Wands, JR and Hayashi, N. Involvement of the p38 mitogen-activated protein kinase cascade in hepatocellular carcinoma. Cancer. 97: 3017-3026, 2003.
Janiak, F, Leber, B and Andrews, DW. Assembly of Bcl-2 into microsomal and outer mitochondrial membranes. Journal of Biological Chemistry. 269: 9842-9849, 1994.
Johnson, GL and Lapadat, R. Mitogen-activated protein kinase pathways mediated by ERK, JNK, and p38 protein kinases. Science. 298: 1911-1912, 2002.
Kane, LP, Shapiro, VS, Stokoe, D and Weiss, A. Induction of NF-kappaB by the AKT/PKB kinase. Current Biology. 9: 601-604, 1999.
Kang, YH and Lee, SJ. The role of p38 MAPK and JNK in arsenic trioxide-induced mitochondrial cell death in human cervical cancer cells. Journal of Cellular Physiology. 217: 23-33, 2008.
Karin, M and Lin, A. NF-kappaB at the crossroads of life and death. Nature Immunology. 3: 221-227, 2002.
Kasibhatla, S, Brunner, T, Genestier, L, Echeverri, F, Mahboubi, A and Green, DR. DNA damaging agents induce expression of Fas ligand and subsequent apoptosis in T lymphocytes via the activation of NF-kappa B and AP-1. Molecular Cell. 1: 543-551, 1998.
Kennedy, NJ, Cellurale, C and Davis, RJ. A radical role for p38 MAPK in tumor initiation. Cancer Cell. 11: 101-103, 2007.
Kim, YJ, Chung, JY, Lee, SG, Kim, JY, Park, JE, Kim, WR, Joo, BS, Han, SH, Yoo, KS, Yoo, YH and Kim, JM. Arsenic trioxide-induced apoptosis in TM4 Sertoli cells: The potential involvement of p21 expression and p53 phosphorylation. Toxicology. 285: 142-151, 2011.
Kuo, CC, Liu, TW, Chen, LT, Shiah, HS, Wu, CM, Cheng, YT, Pan, WY, Liu, JF, Chen, KL, Yang, YN, Chen, SN and Chang, JY. Combination of arsenic trioxide and BCNU synergistically triggers redox-mediated autophagic cell death in human solid tumors. Free Radical Biology and Medicine. 51: 2195-2209, 2011.
Kuwana, T, Mackey, MR, Perkins, G, Ellisman, MH, Latterich, M, Schneiter, R, Green, DR and Newmeyer, DD. Bid, Bax, and lipids cooperate to form supramolecular openings in the outer mitochondrial membrane. Cell. 111: 331-342, 2002.
La Rosee, P, Johnson, K, O'Dwyer, ME and Druker, BJ. In vitro studies of the combination of imatinib mesylate (Gleevec) and arsenic trioxide (Trisenox) in chronic myelogenous leukemia. Experimental Hematology. 30: 729-737, 2002.
Lee, ER, Kim, JY, Kang, YJ, Ahn, JY, Kim, JH, Kim, BW, Choi, HY, Jeong, MY and Cho, SG. Interplay between PI3K/Akt and MAPK signaling pathways in DNA-damaging drug-induced apoptosis. Biochimica et Biophysica Acta. 1763: 958-968, 2006.
Lei, K and Davis, RJ. JNK phosphorylation of Bim-related members of the Bcl2 family induces Bax-dependent apoptosis. Proceedings of the National Academy of Sciences of the United States of America. 100: 2432-2437, 2003.
Li, YM and Broome, JD. Arsenic targets tubulins to induce apoptosis in myeloid leukemia cells. Cancer Research. 59: 776-780, 1999.
Liao, WT, Chang, KL, Yu, CL, Chen, GS, Chang, LW and Yu, HS. Arsenic induces human keratinocyte apoptosis by the FAS/FAS ligand pathway, which correlates with alterations in NF-kappaB and AP-1 activity. Journal of Investigative Dermatology. 122: 125-129, 2004.
Liu, WH and Chang, LS. Fas/FasL-dependent and -independent activation of caspase-8 in doxorubicin-treated human breast cancer MCF-7 cells: ADAM10 down-regulation activates Fas/FasL signaling pathway. International Journal of Biochemistry and Cell Biology. 43: 1708-1719, 2011.
Lowry, OH, Rosebrough, NJ, Farr, AL and Randall, RJ. Protein measurement with the Folin phenol reagent. Journal of Biological Chemistry. 193: 265-275, 1951.
Lynn, S, Gurr, JR, Lai, HT and Jan, KY. NADH oxidase activation is involved in arsenite-induced oxidative DNA damage in human vascular smooth muscle cells. Circulation Research. 86: 514-519, 2000.
Mak, NK, Wong, RNS, Leung, KN and Fung, MC. Involvement of tumor necrosis factor (TNF-α) in arsenic trioxide induced apoptotic cell death of murine myeloid leukemia cells. Toxicology Letters. 135: 79-87, 2002.
Mann, KK, Colombo, M and Wilson H. Miller, J. Arsenic trioxide decreases AKT protein in a caspase-dependent manner. Molecular Cancer Therapeutics. 7: 1680-1687, 2008.
Martindale, JL and Holbrook, NJ. Cellular response to oxidative stress: signaling for suicide and survival. Journal of Cellular Physiology. 192: 1-15, 2002.
Martinez-Outschoorn, UE, Goldberg, A, Lin, Z, Ko, YH, Flomenberg, N, Wang, CG, Pavlides, S, Pestell, RG, Howell, A, Sotgia, F and Lisanti, MP. Anti-estrogen resistance in breast cancer is induced by the tumor microenvironment and can be overcome by inhibiting mitochondrial function in epithelial cancer cells. Cancer Biology & Therapy. 12: 924-938, 2011.
Matsui, K, Fine, A, Zhu, B, Marshak-Rothstein, A and Ju, ST. Identification of two NF-kappa B sites in mouse CD95 ligand (Fas ligand) promoter: functional analysis in T cell hybridoma. Journal of Immunology. 161: 3469-3473, 1998.
McCabe, MJ, Singh, KP, Reddy, SA, Chelladurai, B, Pounds, JG, Reiners, JJ and States, JC. Sensitivity of myelomonocytic leukemia cells to arsenite-induced cell cycle disruption, apoptosis, and enhanced differentiation is dependent on the inter-relationship between arsenic concentration, duration of treatment, and cell cycle phase. Journal of Pharmacology and Experimental Therapeutics. 295: 724-733, 2000.
McEligot, AJ, Yang, S and Meyskens, FL, Jr. Redox regulation by intrinsic species and extrinsic nutrients in normal and cancer cells. Annual Review of Nutrition. 25: 261-295, 2005.
McKiernan, JM, Goluboff, ET, Liberson, GL, Golden, R and Fisch, H. Rising risk of testicular cancer by birth cohort in the United States from 1973 to 1995. Journal of Urology. 162: 361-363, 1999.
Micheau, O, Solary, E, Hammann, A and Dimanche-Boitrel, MT. Fas ligand-independent, FADD-mediated activation of the Fas death pathway by anticancer drugs. Journal of Biological Chemistry. 274: 7987-7992, 1999.
Micheau, O and Tschopp, J. Induction of TNF receptor I-mediated apoptosis via two sequential signaling complexes. Cell. 114: 181-190, 2003.
Miller, WH, Schipper, HM, Lee, JS, Singer, J and Waxman, S. Mechanisms of action of arsenic trioxide. Cancer Research. 62: 3893-3903, 2002.
Morales, AA, Gutman, D, Lee, KP and Boise, LH. BH3-only proteins Noxa, Bmf, and Bim are necessary for arsenic trioxide-induced cell death in myeloma. Blood. 111: 5152-5262, 2009.
Mullen, P. PARP cleavage as a means of assessing apoptosis. Methods in Molecular Medicine. 88: 171-181, 2004.
Nagata, S. Apoptosis by death factor. Cell. 88: 355-365, 1997.
Orrenius, S, Gogvadze, V and Zhivotovsky, B. Mitochondrial oxidative stress: implications for cell death. Annual Review of Pharmacology and Toxicology. 47: 143-183, 2007.
Pearson, G, Robinson, F, Beers Gibson, T, Xu, B-e, Karandikar, M, Berman, K and Cobb, MH. Mitogen-activated protein (MAP) kinase pathways: regulation and physiological functions. Endocrine Reviews. 22: 153-183, 2001.
Pietenpol, JA and Stewart, ZA. Cell cycle checkpoint signaling: cell cycle arrest versus apoptosis. Toxicology. 181-182: 475-481, 2002.
Riccardi, C and Nicoletti, I. Analysis of apoptosis by propidium iodide staining and flow cytometry. Nature Protocols. 1: 1458-1461, 2006.
Rosen, BP. Biochemistry of arsenic detoxification. FEBS Letters. 529: 86-92, 2002.
Sakurai, T, Ochiai, M, Kojima, C, Ohta, T, Sakurai, MH, Takada, NO, Qu, W, Waalkes, MP and Fujiwaraa, K. Role of glutathione in dimethylarsinic acid-induced apoptosis. Toxicology and Applied Pharmacology. 198: 354-365, 2004.
Scholz, C, Richter, A, Lehmann, M, Schulze-Osthoff, K, Dorken, B and Daniel, PT. Arsenic trioxide induces regulated, death receptor-independent cell death through a Bcl-2-controlled pathway. Oncogene. 24: 7031-7042, 2005.
Shen, ZX, Chen, GQ, Ni, JH, Li, XS, Xiong, SM, Qiu, QY, Zhu, J, Tang, W, Sun, GL, Yang, KQ, Chen, Y, Zhou, L, Fang, Z-W, Wang, YT, Ma, J, Zhang, P, Zhang, TD, Chen, SJ, Chen, Z and Wang, ZY. Use of arsenic trioxide (As2O3) in the treatment of acute promyelocytic leukemia (APL): II. clinical efficacy and pharmacokinetics in relapsed patients. Blood. 89: 3354-3360, 1997.
Snow, ET. Metal carcinogenesis: mechanistic implications. Pharmacology and Therapeutics. 53: 31-65, 1992.
Styblo, M, Del Razo, LM, LeCluyse, EL, Hamilton, GA, Wang, C, Cullen, WR and Thomas, DJ. Metabolism of arsenic in primary cultures of human and rat hepatocytes. Chemical Research in Toxicology. 12: 560-565, 1999.
Styblo, M, Del Razo, LM, Vega, L, Germolec, DR, LeCluyse, EL, Hamilton, GA, Reed, W, Wang, C, Cullen, WR and Thomas, DJ. Comparative toxicity of trivalent and pentavalent inorganic and methylated arsenicals in rat and human cells. Archives of Toxicology. 74: 289-299, 2000.
Taylor, RC, Cullen, SP and Martin, SJ. Apoptosis: controlled demolition at the cellular level. Nature Reviews. 9: 231-241, 2008.
Ter Welle, HF and Slater, EC. Uncoupling of respiratory-chain phosphorylation by arsenate. Biochimica et Biophysica Acta (BBA) - Bioenergetics. 143: 1-17, 1967.
Thornton, TM and Rincon, M. Non-classical p38 map kinase functions: cell cycle checkpoints and survival. International journal of biological sciences. 5: 44-51, 2009.
Tsuruta, F, Sunayama, J, Mori, Y, Hattori, S, Shimizu, S, Tsujimoto, Y, Yoshioka, K, Masuyama, N and Gotoh, Y. JNK promotes Bax translocation to mitochondria through phosphorylation of 14-3-3 proteins. EMBO Journal. 23: 1889-1899, 2004.
Uslu, R, Sanli, UA, Sezgin, C, Karabulut, B, Terzioglu, E, Omay, SB and Goker, E. Arsenic trioxide-mediated cytotoxicity and apoptosis in prostate and ovarian carcinoma cell lines. Clinical Cancer Research. 6: 4957-4964, 2000.
Vivanco, I and Sawyers, CL. The phosphatidylinositol 3-Kinase-AKT pathway in human cancer. Nature Reviews Cancer. 2: 489-501, 2002.
Wada, T and Penninger, JM. Mitogen-activated protein kinases in apoptosis regulation. Oncogene. 23: 2838-2849, 2004.
Wang, X, McCullough, KD, Franke, TF and Holbrook, NJ. Epidermal growth factor receptor-dependent Akt activation by oxidative stress enhances cell survival. Journal of Biological Chemistry. 275: 14624-14631, 2000.
Westwick, JK, Bielawska, AE, Dbaibo, G, Hannun, YA and Brenner, DA. Ceramide activates the stress-activated protein kinases. Journal of Biological Chemistry. 270: 22689-22692, 1995.
Yuan, Z, Wang, F, Zhao, Z, Zhao, X, Qiu, J, Nie, C and Wei, Y. BIM-mediated AKT phosphorylation is a key modulator of arsenic trioxide-induced apoptosis in cisplatin-sensitive and -resistant ovarian cancer cells. PLoS One. 6: e20586, 2011.
Zamzami, N, Marchetti, P, Castedo, M, Decaudin, D, Macho, A, Hirsch, T, Susin, SA, Petit, PX, Mignotte, B and Kroemer, G. Sequential reduction of mitochondrial transmembrane potential and generation of reactive oxygen species in early programmed cell death. Journal of Experimental Medicine. 182: 367-377, 1995.
Zanke, BW, Boudreau, K, Rubie, E, Winnett, E, Tibbles, LA, Zon, L, Kyriakis, J, Liu, FF and Woodgett, JR. The stress-activated protein kinase pathway mediates cell death following injury induced by cis-platinum, UV irradiation or heat. Current Biology. 6: 606-613, 1996.
Zimmermann, KC, Bonzon, C and Green, DR. The machinery of programmed cell death. Pharmacology and Therapeutics. 92: 57-70, 2001.