Additional Supporting Information may be found in the online version of this article. “
“By array-comparative genomic hybridization, we demonstrated cyclin E as one of seven genes associated with mTOR inhibitor hepatocellular carcinoma (HCC) development in Ku70 DNA repair-deficient mice. We therefore explored the hypothesis that during hepatocarcinogenesis, cyclin E kinase can overcome the inhibitory effects of p53 and establish whether abnormal

miRNA(mi-R)-34, a co-regulator of cyclin E and p53, can account for their interactions as “drivers” of HCC. Dysplastic hepatocytes (DNs) and HCCs were generated from diethylnitrosamine (DEN)-injected C57BL/6 male mice at 3–12 months. Cyclin E/cdk2 was barely expressed in normal liver, but was readily detected in dysplastic hepatocytes, localizing to glutathione-S transferase pi-form positive cells dissected by laser-dissection. Cyclin E kinase activity BGB324 in vivo preceded cyclin D1, proliferating cell nuclear antigen

expression in DNs and HCCs despite maximal p53 and p21 expression. We confirmed that cyclin E, rather than cyclin D1, is the proliferative driver in hepatocarcinogenesis by immunoprecipitation experiments demonstrating preferential binding of p21 to cyclin D1, allowing cyclin E-mediated “escape” from G1/S checkpoint. We then showed cyclin E was responsible for regulating wild-type p53 by knockdown experiments in primary HCC cells; cyclin E-knockdown increased p53 and p21, diminished anti-apoptotic Bcl-XL and reduced cell viability. Conversely, blocking p53 augmented cyclin E, Bcl-XL expression and increased proliferation. Physiological interactions between cyclin E/p53/p21 were confirmed in primary hepatocytes. miR-34a,c were upregulated in dysplastic murine, human liver and HCCs compared with normal liver, and appeared to be linked to cyclin E/p53. Upregulation selleck kinase inhibitor of functionally active cyclin E via miR34 with loss of p53 function is associated with cell-cycle checkpoint failure increasing proliferative drive that favors hepatocarcinogenesis. “
“Epithelial cell

adhesion molecule (EpCAM) is a surface marker on human hepatic stem/progenitor cells that is reported as absent on mature hepatocytes. However, it has also been noted that in cirrhotic livers of diverse causes, many hepatocytes have EpCAM surface expression; this may represent aberrant EpCAM expression in injured hepatocytes or, as we now hypothesize, persistence of EpCAM in hepatocytes that have recently derived from hepatobiliary progenitors. To evaluate this concept, we investigated patterns of EpCAM expression in hepatobiliary cell compartments of liver biopsy specimens from patients with all stages of chronic hepatitis B and C, studying proliferation, senescence and telomere lengths.