title: Potentiation of paclitaxel-induced apoptosis by the novel cyclin-dependent kinase inhibitor NU6140: a possible role for survivin down-regulation.
abstract: Cyclin-dependent kinases (CDK) play a crucial role in the control of the cell cycle. Aberrations in the control of cell cycle progression occur in the majority of human malignancies; hence, CDKs are promising targets for anticancer therapy. Here, we define the cellular effects of the novel CDK inhibitor NU6140, alone or in association with paclitaxel, with respect to inhibition of cell proliferation and cell cycle progression and induction of apoptosis in HeLa cervical carcinoma cells and in comparison with purvalanol A. Both CDK inhibitors induced a concentration-dependent cell cycle arrest at the G(2)-M phase and an increase in the apoptotic rate, with a concomitant down-regulation of the antiapoptotic protein survivin, a member of the inhibitors of apoptosis protein family. Notably, the addition of NU6140 to paclitaxel-treated cells resulted in markedly increased cytotoxic effect and apoptotic response in comparison with the paclitaxel-purvalanol A combination (86 +/- 11% and 37 +/- 8%, respectively). Similarly, the extent of caspase-9 and caspase-3 activation in paclitaxel-NU6140-treated cells was approximately 4-fold higher than after the paclitaxel-purvalanol A combination. Moreover, an almost complete abrogation of the expression of the active, Thr(34)-phosphorylated form of survivin was observed in cells exposed to the paclitaxel-NU6140 combination. A synergistic effect of the paclitaxel-NU6140 combination, as a consequence of survivin inhibition and increased activation of caspase-9 and caspase-3, was also observed in OAW42/e ovarian cancer line but not in the derived OAW42/Surv subline ectopically expressing survivin. Results from this study indicate that NU6140 significantly potentiates the apoptotic effect of paclitaxel, with inhibition of survivin expression/phosphorylation as the potential mechanism.
authors.affiliation: Department of Experimental Oncology, Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Marzia
authors.initials: M
authors.lastname: Pennati
authors.forename: Allyson J
authors.initials: AJ
authors.lastname: Campbell
authors.forename: Maria
authors.initials: M
authors.lastname: Curto
authors.forename: Mara
authors.initials: M
authors.lastname: Binda
authors.forename: Yuzhu
authors.initials: Y
authors.lastname: Cheng
authors.forename: Lan-Zeng
authors.initials: LZ
authors.lastname: Wang
authors.forename: Nicola
authors.initials: N
authors.lastname: Curtin
authors.forename: Bernard T
authors.initials: BT
authors.lastname: Golding
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Griffin
authors.forename: Ian R
authors.initials: IR
authors.lastname: Hardcastle
authors.forename: Andrew
authors.initials: A
authors.lastname: Henderson
authors.forename: Nadia
authors.initials: N
authors.lastname: Zaffaroni
authors.forename: David R
authors.initials: DR
authors.lastname: Newell
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D015536:Down-Regulation; D004338:Drug Combinations; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D006367:HeLa Cells; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D015394:Molecular Structure; D009363:Neoplasm Proteins / Q000378:metabolism*; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D017239:Paclitaxel / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D011687:Purines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000077022:Survivin; D014407:Tumor Cells, Cultured
chemical_list: C506606:4-(6-cyclohexylmethoxy-9H-purin-2-ylamino)-N,N-diethylbenzamide; C471843:6-((3-chloro)anilino)-2-(isopropyl-2-hydroxyethylamino)-9-isopropylpurine; D000972:Antineoplastic Agents, Phytogenic; C107489:BIRC5 protein, human; D004338:Drug Combinations; D004791:Enzyme Inhibitors; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D011687:Purines; D000077022:Survivin; D018844:Cyclin-Dependent Kinases; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D017239:Paclitaxel