title: The role of Cdk5 in retinoic acid-induced apoptosis of cervical cancer cell line.
abstract: Cdk5 is a small serine/threonine protein kinase which belongs to Cdk family. Unlike other Cdk members, so far Cdk5 is known to be irrelevant in cell cycle. Cdk5 kinase activity is regulated by binding with its activator, p35. Our previous results indicate that CdkS and p35 are involved in drugs-induced apoptosis of prostate cancer cells. Retinoic acid (RA) is one of the vitamin A-related compounds. Because of its potency on biological functions, it has been widely studied in its novel actions including the ability to inhibit cancer cell growth and to induce apoptosis. Here, we report that RA treatment decreased the growth of human cervical cancer cell line, HeLa, and Cdk5 contributed to this effect. The involvement of Cdk5 in RA-reduced cell survival was performed by treatments of Cdk5 inhibitor and siRNA. We further identified that RA-induced growth inhibition was partly correlated to Cdk5 activity-related apoptosis by detecting cell cycle distribution of sub G1 phase and the signals of Annexin V staining. In addition, our results also indicated that Cdk5 activity was involved in RA-induced HeLa apoptosis by detecting cleavages of caspase-3 and its substrate, PARP (poly (ADP-ribose) polymerases) Interestingly, the nuclear localizations of Cdk5 and p35 proteins were increased by RA treatment, which, again, suggests the involvement of Cdk5 and p35 in RA-induced apoptotic effects. In conclusion, we provide evidence to suggest that Cdk5 and p35 might play important roles in RA-induced HeLa apoptosis.
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan, Republic of China.
authors.forename: Hung-Shou
authors.initials: HS
authors.lastname: Kuo
authors.forename: Fu-Ning
authors.initials: FN
authors.lastname: Hsu
authors.forename: Ming-Ching
authors.initials: MC
authors.lastname: Chiang
authors.forename: Shuen-Chi
authors.initials: SC
authors.lastname: You
authors.forename: Mei-Chih
authors.initials: MC
authors.lastname: Chen
authors.forename: Ming-Jae
authors.initials: MJ
authors.lastname: Lo
authors.forename: Ho
authors.initials: H
authors.lastname: Lin
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology*; D053148:Caspase 3 / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D051360:Cyclin-Dependent Kinase 5 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D005260:Female; D016193:G1 Phase / Q000187:drug effects / Q000502:physiology; D006131:Growth Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D011687:Purines / Q000494:pharmacology; D034741:RNA, Small Interfering; D000077546:Roscovitine; D014212:Tretinoin / Q000494:pharmacology*; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; C500695:CDCA5 protein, human; D018797:Cell Cycle Proteins; D006131:Growth Inhibitors; D011687:Purines; D034741:RNA, Small Interfering; D000077546:Roscovitine; D014212:Tretinoin; D051360:Cyclin-Dependent Kinase 5; C495905:CDK5 protein, human; C505407:CASP3 protein, human; D053148:Caspase 3