title: Pro-caspase-3 overexpression sensitises ovarian cancer cells to proteasome inhibitors.
abstract: The ubiquitin-proteasome pathway plays a critical role in the degradation of several proteins involved in the cell cycle. Dysregulation of this pathway leads to inhibition of cellular proliferation and the induction of apoptosis. Ubiquitination and its downstream consequences have been investigated intensively as targets for the development of drugs for tumour therapy. Here we have investigated the mechanism of apoptosis induced by the proteasome inhibitors MG-132, lactacystin and calpain inhibitor I (ALLN), in the HEK 293 cell line and the ovarian cancer cell lines SKOV3 and OVCAR3. We have found strong caspase-3-like and caspase-6-like activation upon treatment of HEK 293 cells with MG-132. Using a tricistronic expression vector based on a tetracycline-responsive system we generated stable SKOV3 nd OVCAR3 cell lines with inducible expression of pro-caspase-3. Induction of pro-caspase-3 expression in normally growing cells does not induce apoptosis. However, in the presence of the proteasome inhibitors MG-132, lactacystin or ALLN we found that cells overexpressing pro-caspase-3 are rapidly targeted for apoptosis. Our results demonstrate that pro-caspase-3 can sensitise ovarian cancer cells to proteasome inhibitor-induced apoptosis, and a combination of these approaches might be exploited for therapy of ovarian and other cancers.
authors.affiliation: ICRF Molecular Oncology Unit, Imperial College School of Medicine at Hammersmith Hospital, London W12 ONN, UK.
authors.forename: T
authors.initials: T
authors.lastname: Tenev
authors.forename: M
authors.initials: M
authors.lastname: Marani
authors.forename: I
authors.initials: I
authors.lastname: McNeish
authors.forename: N R
authors.initials: NR
authors.lastname: Lemoine
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D053148:Caspase 3; D020169:Caspases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D004790:Enzyme Induction; D005260:Female; D005434:Flow Cytometry; D016195:G2 Phase / Q000187:drug effects; D006023:Glycoproteins / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D007527:Isoenzymes / Q000096:biosynthesis / Q000378:metabolism; D007976:Leupeptins / Q000494:pharmacology; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D014162:Transfection
chemical_list: D000970:Antineoplastic Agents; D015853:Cysteine Proteinase Inhibitors; D006023:Glycoproteins; D007527:Isoenzymes; D007976:Leupeptins; C039304:calpain inhibitors; C067713:lactacystin; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; D000111:Acetylcysteine