title: Involvement of oxidative stress-induced ERK/JNK activation in the Cu(2+)/pyrrolidine dithiocarbamate complex-triggered mitochondria-regulated apoptosis in pancreatic β-cells.
abstract: Oxidative stress was demonstrated to promote the progression of diabetes mellitus (DM). It has been suggested that copper may play a specific role in the progression and pathogenesis of DM. Pyrrolidine dithiocarbamate (PDTC), a widely apply to the medicine, was known to be capable of enhancing copper accumulation. In this study, we investigated the effect of submicromolar-concentration Cu(2+)/PDTC complex on pancreatic β-cell damage and evaluated the role of oxidative stress in this effect. CuCl(2) (0.01-300μM) did not affect the cell viability in β-cell line RIN-m5F cells. However, combination of CuCl(2) (0.5μM) and PDTC (0.3μM) markedly reduced RIN-m5F cell viability. Cu(2+)/PDTC complex could also increase the LPO and decrease the intracellular reduced GSH levels, and display several features of apoptosis signals including: increase in sub-G1 cell population, annexin-V binding, and caspase-3 activity, mitochondrial dysfunctions, and the activation of PARP and caspase cascades, which accompanied with the marked increase the intracellular Cu(2+) levels. These apoptotic-related responses of Cu(2+)/PDTC complex-induced could be effectively prevented by antioxidant N-acetylcysteine (NAC). Furthermore, Cu(2+)/PDTC complex was capable of increasing the phosphorylations of ERK1/2 and JNK, and its upstream kinase MEK1/2 and MKK4, which could be reversed by NAC. Transfection with ERK2- and JNK-specific si-RNA and specific inhibitors SP600125 and PD98059 could inhibit ERK1/2 and JNK activation and attenuate MMP loss and caspase-3 activity induced by the Cu(2+)/PDTC complex. Taken together, these results are the first report to demonstrate that the Cu(2+)/PDTC complex triggers a mitochondria-regulated apoptosis via an oxidative stress-induced ERK/JNK activation-related pathway in pancreatic β-cells.
authors.affiliation: Department of Public Health, China Medical University, Taichung 404, Taiwan.
authors.forename: Chin-Ching
authors.initials: CC
authors.lastname: Wu
authors.forename: Cheng-Chieh
authors.initials: CC
authors.lastname: Yen
authors.forename: kuan-I
authors.initials: kI
authors.lastname: Lee
authors.forename: Chin-Chuan
authors.initials: CC
authors.lastname: Su
authors.forename: Feng-Cheng
authors.initials: FC
authors.lastname: Tang
authors.forename: Kuo-Liang
authors.initials: KL
authors.lastname: Chen
authors.forename: Yi-Chang
authors.initials: YC
authors.lastname: Su
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Chen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003300:Copper / Q000633:toxicity*; D003920:Diabetes Mellitus / Q000378:metabolism* / Q000473:pathology; D004789:Enzyme Activation; D005434:Flow Cytometry; D005978:Glutathione / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D011759:Pyrrolidines / Q000633:toxicity*; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D013859:Thiocarbamates / Q000633:toxicity*
chemical_list: D011759:Pyrrolidines; D034741:RNA, Small Interfering; D013859:Thiocarbamates; C020972:pyrrolidine dithiocarbamic acid; D003300:Copper; D020928:Mitogen-Activated Protein Kinases; D005978:Glutathione