Cisplatin induces cell cycle arrest and senescence via upregulating P53 and P21 expression in HepG2 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>Cellular senescence as one of the important steps against tumor is observed in many cancer patients receiving chemotherapy and is related to chemotherapeutic response. To investigate the effect of cisplatin on hepatocellular carcinoma, we treated HepG2 cells exhibiting wild-type TP53 with gradient concentrations of cisplatin.</p><p><b>METHODS</b>The inhibitory effects of cisplatin on human hepatoma HepG2 cells were detected by MTT assay and colony formation test. The changes in cell cycle were analyzed by flow cytometry, and cellular senescence was detected with senescence associated β-galactosidase (SA β-gal) staining. The relative mRNA expression levels of TP53, P21 and P19 was estimated using semi-quantitative real-time RT-PCR, and the protein expressions of P53 and P21 were detected using Western blotting.</p><p><b>RESULTS</b>Cisplatin induced irreversible proliferation inhibition and G1 phase arrest of HepG2 cells. Elevated levels of senescence-associated β-galactosidase was observed in HepG2 cells exposed to low doses of cisplatin. P19 expression immediately increased following cisplatin exposure and reached the maximum level at 48 h, followed then by a rapid decrease to the baseline level, whereas the expressions levels of TP53 and P21 mRNA increased continuously. Western blotting confirmed P53 and P21 expression changes similar to their mRNA expressions during cisplatin-induced cellular senescence in HepG2 cells.</p><p><b>CONCLUSION</b>Our results revealed a functional link between cisplatin and hepatocellular senescence. Cellular senescence induced by cisplatin as a stabile senescent cellular model can be used for further research.</p>

Inflammation: a key factor of gallbladder cancer / 中华肝胆外科杂志

Previous studies have suggested that various kinds of inflammatory factors can influence the formation and development of tumor cells.Researche has shown that gallbladder cancer is closely linked with local inflammation,which is a risk factor for the development of gallbladder cancer.It is widely known that cholecystitis is closely correlated with gallstones,and that bile obtained from patients with gallbladder cancer contains a large variety of bacteria,such as Salmonella typhi,Helicobacter,and Escherichia coli.It is proposed that the gallbladder may be the result of the joint action of inflammation with the bacterial flora.Similarly,the inflammatory “tumor infiltrating lymphocyte” (TIL)can be observed in the tumor and its surrounding tissues,and may also play a role in tumor growth and metastasis.However,detailed mechanisms about the relationship between inflammation and gallbladder cancer is still not clear.No specific anti-inflammatory drugs for gallbladder cancer have been developed. In the near future,anti inflammatory drugs may play a more important role in gallbladder cancer prevention and treatment.