title: Loss of Cyclin B1 followed by downregulation of Cyclin A/Cdk2, apoptosis and antiproliferation in Hela cell line.
abstract: Recent studies have shown that Cyclin B1 is overexpressed in various tumor types but present at low levels in normal tissues. To explore the possibility of employing Cyclin B1 as an anticancer target, we knocked down Cyclin B1 in an HeLa cell line using RNA interference (RNAi). Subsequently, we monitored cell cycle-related molecules by Western blot together with immunofluorescence and determined cell cycle distribution by flow cytometry. XTT and soft agar colony growth experiments were performed to detect cell viability and proliferation. Furthermore, we analyzed cell apoptosis by measuring Bcl-2 and Bax protein level and DNA-ladder assay. After performing Cyclin B1 RNAi, Cyclin B1, Cyclin A and Cdk2 protein levels were found to be markedly downregulated, whereas Cdc2 was almost unaffected; S-phase fraction increased significantly; HeLa cell viability and cell colony forming ability were markedly diminished after the RNAi; Bcl-2 was noticeably attenuated but Bax was hardly changed; and HeLa cells displayed typical DNA ladder. The loss of Cyclin B1 resulted in the downregulation of Cyclin A and Cdk2, S-phase delay and eventually led to cell apoptosis and the decrease of cell viability and proliferation. Our studies suggest that Cyclin B1 may be a promising anticancer target.
authors.affiliation: Brain Korea 21 Project for Medical Science, Yonsei Univesity, Seoul, Korea.
authors.forename: Xian He
authors.initials: XH
authors.lastname: Xie
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: An
authors.forename: Suki
authors.initials: S
authors.lastname: Kang
authors.forename: Sunghui
authors.initials: S
authors.lastname: Hong
authors.forename: Yoon Pyo
authors.initials: YP
authors.lastname: Choi
authors.forename: Young Tae
authors.initials: YT
authors.lastname: Kim
authors.forename: Young Deuk
authors.initials: YD
authors.lastname: Choi
authors.forename: Nam Hoon
authors.initials: NH
authors.lastname: Cho
mesh_terms: D017209:Apoptosis; D015153:Blotting, Western; D042846:CDC2-CDC28 Kinases / Q000096:biosynthesis*; D049109:Cell Proliferation; D002470:Cell Survival; D019925:Cyclin A / Q000096:biosynthesis*; D019926:Cyclin B / Q000235:genetics* / Q000502:physiology*; D056744:Cyclin B1; D051357:Cyclin-Dependent Kinase 2; D015536:Down-Regulation; D005434:Flow Cytometry; D006367:HeLa Cells; D006801:Humans; D034622:RNA Interference
chemical_list: C534699:CCNB1 protein, human; D019925:Cyclin A; D019926:Cyclin B; D056744:Cyclin B1; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2