title: Small interfering RNA-mediated silencing of mitochondrial NADP+-dependent isocitrate dehydrogenase enhances the sensitivity of HeLa cells toward tumor necrosis factor-alpha and anticancer drugs.
abstract: Tumor necrosis factor-alpha (TNF-alpha) and several anticancer drugs induce the production of reactive oxygen species, which play an important causative role in apoptotic cell death. Recently, we demonstrated that the control of mitochondrial redox balance and the cellular defense against oxidative damage is one of the primary functions of mitochondrial NADP(+)-dependent isocitrate dehydrogenase (IDPm) by supplying NADPH for antioxidant systems. In the present report, we show that silencing of IDPm expression in HeLa cells greatly enhances apoptosis induced by TNF-alpha and anticancer drugs. Transfection of HeLa cells with an IDPm small interfering RNA (siRNA) markedly decreased activity of IDPm, enhancing the susceptibility of anticancer agent-induced apoptosis reflected by morphological evidence of apoptosis, DNA fragmentation, cellular redox status, mitochondria redox status and function, and the modulation of apoptotic marker proteins. These results indicate that IDPm may play an important role in regulating the apoptosis induced by TNF-alpha and anticancer drugs and the sensitizing effect of IDPm siRNA on the apoptotic cell death of HeLa cells offers the possibility of developing a modifier of cancer chemotherapy.
authors.affiliation: School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Taegu 702-701, Korea.
authors.forename: In Sup
authors.initials: IS
authors.lastname: Kil
authors.forename: Sung Youl
authors.initials: SY
authors.lastname: Kim
authors.forename: Sun Joo
authors.initials: SJ
authors.lastname: Lee
authors.forename: Jeen-Woo
authors.initials: JW
authors.lastname: Park
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology; D034741:RNA, Small Interfering / Q000502:physiology*; D019311:Staurosporine / Q000494:pharmacology*; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology / Q000502:physiology*
chemical_list: D000970:Antineoplastic Agents; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha; D007521:Isocitrate Dehydrogenase; C039355:isocitrate dehydrogenase (NADP+); D019311:Staurosporine