Here, we focused on elucidating how UCN 01 induces G2M arrest in Huh7, HepG2, and Hep3B cell lines. Among these cell lines, Huh7 is p53 mutant and p21 defective, and Hep3B is p53 defective, concerning enabling us to de termine whether the cell cycle arrest is p53 dependent. The cyclin BCdk2 complex is critical in regulating the cell cycle transition from G2 to M phase and is con trolled by phosphorylation at various sites. In our study, significant decreases in cyclin B and CDC25, as well as an increase in phosphorylated CHK2, were ob served after 24 h of UCN 01 Inhibitors,Modulators,Libraries treatment. Cdc25 is a posi tive regulator of the cyclin B complex, which is inhibited by Chk2 mediated phosphorylation. Thus, UCN 01 may induce G2M cell cycle arrest through the CHK2 CDC25 cyclin B pathway.

However, we found that UCN 01 induces p53 phos phorylation at Ser 15 and increased p21waf1 protein levels in the HepG2 cell line. As a crucial cell Inhibitors,Modulators,Libraries cycle regu lator, the p53 tumour suppressor has an important role in the cellular response to platinum agents. For example, 1,2 diaminocyclohexane acetato Pt arrests p53 wild type Inhibitors,Modulators,Libraries cells in G1 and mutant p53 cells in G2M phase in ovarian cancer. P53 transcriptionally activates a series of genes involved in both the G1 S and the G2M transitions in response to genotoxic stress. Among these genes, p21 is a well established negative regulator of the G1S transition. p21 also inhibits the CDK1cyclin B complex and maintains the G2 arrest. Our study shows that the p53p21waf1 pathway is also involved in the G2M cell cycle arrest of HepG2 cells. Interestingly, when UCN 01 was used to treat Huh7 cells and Hep3B cells.

the G2M arrest is still observed. These findings suggest that, although these two pathways both contribute to cell cycle arrest, the CHK2 Cdc25c pathway may have a more important role in these p53 deficient cell lines. In our study, UCN 01 induces G2M cell cycle Inhibitors,Modulators,Libraries arrest through these two pathways in the Huh7, HepG2, and Hep3B cell lines. but does not affect normal hepatocytes, Inhibitors,Modulators,Libraries which may be attributed to the slow turn over rate of normal hepatocytes. Finally, we found that Huh7 cell invasive activity was significantly inhibited by UCN 01. Recent studies indi cate that phosphorylated B catenin has a critical role in the invasion and development of many different tumours.

B catenin was originally identified as a component of cell cell adhesion structures, interacting with the cyto plasmic domain of E cadherin and linking E cadherin to catenin. Phosphorylation of B catenin causes its dissoci ation from these cell http://www.selleckchem.com/products/Gemcitabine-Hydrochloride(Gemzar).html cell contacts, and B catenin accumu lates in both the cytosol and nucleus, enhancing its interaction with 14 3 3via a binding motif containing Ser 552. In our study, we examined total B catenin and phosphorylated B catenin levels at different time points, and found that phosphorylated B catenin decreased 18 h after 100 nM UCN 01 treatment.