The Study Of CDKN3in Hepatocellular Carcinogenesis And Progress

Hepatocellular carcinoma (HCC) is a common cancer worldwide, with half of the new cases appeared in China. Though the advancement of the treatment, the prognosis of HCC remains dismal. To develop the effective therapeutic approaches of HCC,it is crucial to understand the molecular mechanisms of HCC and find novel targets for the treatment of HCC.Cyclin-dependent kinase inhibitor3(CDKN3) belongs to the protein phosphatases family and functions as the cell cycle regulator. It has a dual function in the regulating of cell cycle. First, CDKN3acts as a cyclin-dependent kinase inhibitor which binds to CDK2kinase selectively and reduce its activity to phosphorylate retinoblastoma protein (Rb). Non-phosphorylated Rb binds to E2F1and prevents the generation of proteins crucial in G1/S transition, finally inhibiting G1/S transition. Second, CDKN3also bind to Mdm2. It could interact with Mdm2-p53complex, therefore blocking the induction of p21, a p53target protein, thus facilitates the progression of cell cycle. Furthermore, CDKN3was found to be deleted or overexpressed in various types of cancers, but its expression pattern and functions in HCC remain to be elucidated.In this study, we aimed to analyze the function and mechanisms of CDKN3in Hepatocellular carcinoma. We found that CDKN3was commonly high-expressed in HCC, and its high expression was positively correlated with poor clinical outcome. Overexpression of CDKN3in HCC cell lines could stimulate its proliferation. After Meta-analyzation of microarray data, a number of cell cycle regulating proteins were found to be co-expressed with CDKN3,and BIRC5located at the central node of the co-expression network.Objective:Cyclin-dependent kinase inhibitor3(CDKN3) belongs to the protein phosphatases family. It could both inhibit and promote the cell cycle. Although the function of CDKN3has been studied in various types of cancers, its function in HCC remains unknown. In this study, we aimed to analyze the function of CDKN3in HCC by molecular biological experiments.Methods:By the use of meta-analysis, western bolting and real time-PCR, we analyze the expression of CDKN3in56pairs of HCC tissues and10HCC cell lines. And analyze the association of its expression with pathological features (such as tumor size, tumor number, tumor stages, vascular invasion and so on). Using plasmid transfection, we analyze the changes of proliferation, apoptosis and invasion of HCC cell lines after enforced expression of CDKN3. By the analyze of microarray data from the study of Wurmbach, Chen, Roessler and Mas, we find61genes co-expressed with CDKN3, these genes are further used for GO analysis with EASE (The Expression Analysis Systematic Explorer). Finally, the transcriptional network are constructed with GePS. Results:CDKN3are commonly over-expressed in HCC tissues and cell lines, and the expression level of CDKN3are positively correlated with HCC tumor stage. Further study found enforced expression of CDKN3could promote the proliferation of HCC cells, and this promotion are correlated with the inhibition of p21protein. Co-expression analysis found a total of61CDKN3co-expressed genes. GO analyze of these genes found these co-expressed genes are enriched in biological processed involved in cell proliferation. After the construction of the functional network of these genes, we found BIRC5was located at the center of the network.Conclusion:CDKN3could increase the proliferation of HCC cells and are involved in HCC carcinogenesis and progress.