nitrophenols and Cholangiocarcinoma

Cholangiocarcinoma responses weakly to cisplatin. Mitochondrial dynamics participate in the response to various stresses, and mainly involve mitophagy and mitochondrial fusion and fission. Bcl-2 family proteins play critical roles in orchestrating mitochondrial dynamics, and are involved in the resistance to cisplatin. Here we reported that ABT737, combined with cisplatin, can promote cholangiocarcinoma cells to undergo apoptosis. We found that the combined treatment decreased the Mcl-1 pro-survival form and increased Bak. Cells undergoing cisplatin treatment showed hyperfused mitochondria, whereas fragmentation was dominant in the mitochondria of cells exposed to the combined treatment, with higher Fis1 levels, decreased Mfn2 and OPA1 levels, increased ratio of Drp1 60kD to 80kD form, and more Drp1 located on mitochondria. More p62 aggregates were observed in cells with fragmented mitochondria, and they gradually translocated to mitochondria. Mitophagy was induced by the combined treatment. Knockdown p62 decreased the Drp1 ratio, increased Tom20, and increased cell viability. Our data indicated that mitochondrial dynamics play an important role in the response of cholangiocarcinoma to cisplatin. ABT737 might enhance cholangiocarcinoma sensitivity to cisplatin through regulation of mitochondrial dynamics and the balance within Bcl-2 family proteins. Furthermore, p62 seems to be critical in the regulation of mitochondrial dynamics.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Biphenyl Compounds; Cell Line; Cell Survival; Cholangiocarcinoma; Cisplatin; Drug Resistance, Neoplasm; Dynamins; GTP Phosphohydrolases; Humans; Membrane Proteins; Membrane Transport Proteins; Microtubule-Associated Proteins; Mitochondria; Mitochondrial Dynamics; Mitochondrial Precursor Protein Import Complex Proteins; Mitochondrial Proteins; Mitophagy; Myeloid Cell Leukemia Sequence 1 Protein; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Receptors, Cell Surface; RNA Interference; RNA-Binding Proteins; RNA, Small Interfering; Sulfonamides

In TFK-1 and EGI-1 cholangiocarcinoma cell lines, zoledronic acid (ZOL) determines an S-phase block without apoptosis. Here, we investigated the occurrence of apoptosis stigmata when ZOL is associated to the BH3-mimetic ABT-737.. In EGI-1 and TFK-1 cholangiocarcinoma cell lines untreated or treated with ABT-737 alone or in combination with ZOL, the pro-survival protein's pattern (BCL-2, BCL-XL, MCL-1, HSP72, HSP27) was investigated by biochemical criteria along with the occurrence of mitochondrial damage evaluated by cytofluorimetric analysis using a cationic dye.. ABT-737 induced growth inhibition and significantly affected the colony-forming ability of both EGI-1 and TFK-1 cells. However, activated PARP-1 or/and caspase-3 cleavage (apoptosis markers) were detected only at the highest ABT-737 concentrations used. Combined treatment showed synergistic effect by converting the predominant cytostatic effect of ZOL into a cytotoxic one as shown by striking increment of mitochondrial harmed cells along with PARP-1 activation and caspase-3 cleavage.. The lack of apoptosis following ZOL treatment in these cholangiocarcinoma cell lines appears to be multifactorial and could be ascribed to the large constitutive expression of pro-survival proteins. The efficacy of ZOL treatment requires a concomitant unleashing of apoptosis using a selective BH3-mimetic as ABT-737. The rational targeting of specific components of the apoptotic pathway may appear a useful approach to improve the treatment of refractory or relapsed cholangiocarcinoma. Combined treatment could be further explored in in vivo tumor model of cholangiocarcinoma.

Topics: Antineoplastic Agents; Apoptosis; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Biphenyl Compounds; Cell Line, Tumor; Cholangiocarcinoma; Diphosphonates; Drug Delivery Systems; Drug Synergism; Gene Expression Regulation; Humans; Imidazoles; Nitrophenols; Piperazines; S Phase; Sulfonamides; Zoledronic Acid