title: Inhibition of Hsp27 and Hsp40 potentiates 5-fluorouracil and carboplatin mediated cell killing in hepatoma cells.
abstract: Heat shock proteins (Hsps) modulate several cellular functions and are ubiquitously present in cell. Here, we investigated alterations in the expression of Hsps and explored functional consequences of the same. Moreover, effect of quercetin (Qctn), an inhibitor of Hsps, on chemotherapeutic drugs treatment in hepatoma cells Hep3B and HepG2 was investigated. We for the first time report that 5-fluorouracil (5-FU) and carboplatin specifically induce expression of Hsp40 in addition to Hsp27 in Hep3B and HepG2 cells. Induction of Hsps following exposure to sub lethal dose of drugs is a cellular challenge to survival. However, under lethal environmental conditions with reduced cell viability, cells fail to sustain the induction of survival proteins, Hsp27 and Hsp40. Though Qctn itself, to certain extent is cytotoxic to cells, it potentiates the pro-apoptotic action of 5-FU and carboplatin, by inhibiting expression of Hsps. The increased cell killing correlates with decreased levels of procaspase-3. Furthermore, siRNA mediated knockdown of Hsp27 and Hsp40 diminishes survival of drugs exposed cells. Altogether, our data provides clear evidence that Hsp27 and 40 promote cell survival and inhibition of their expression does not allow cells to adapt to drug exposure and survive. Collectively, our novel findings on compelling action of 5-FU or carboplatin following knockdown of Hsp40 and that of Hsp27 highlights their strategic implications towards an effective therapy against HCC.
authors.affiliation: National Centre for Cell Science, NCCS Complex, Ganeshkhind, Pune, India.
authors.forename: Aanchal
authors.initials: A
authors.lastname: Sharma
authors.forename: Ankur Kumar
authors.initials: AK
authors.lastname: Upadhyay
authors.forename: Manoj Kumar
authors.initials: MK
authors.lastname: Bhat
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D016190:Carboplatin / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D045744:Cell Line, Tumor / Q000166:cytology / Q000187:drug effects; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D005472:Fluorouracil / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D055551:HSP27 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D050956:HSP40 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D006360:Heat-Shock Proteins; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology*; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D011794:Quercetin / Q000494:pharmacology*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000494:pharmacology; D014162:Transfection
chemical_list: D000964:Antimetabolites, Antineoplastic; D018906:Antineoplastic Agents, Alkylating; C494647:DNAJB1 protein, human; D055551:HSP27 Heat-Shock Proteins; D050956:HSP40 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D034741:RNA, Small Interfering; D011794:Quercetin; D016190:Carboplatin; D005472:Fluorouracil