| Part I:Expression of USP22in gastric cancer and the clinical significanceObjective:To investigate the expression of USP22in gastric cancer and the clinical significance.Methods:The expression of USP22protein was detected in100gastric cancer and46normal tissues by immunohistochemistry.Results:The expression of USP22was significantly higher in gastric cancer than normal tissues. And there was positive correlation with the expression level of gastric cancers and the grade of tumor, and there was a negative correlation with the expression level of gastric caners and the differentiation.Conclusion:USP22was a putative cancer biomarker of gastric cancer. Part II:SiRNA-mediated silencing of the USP22gene inhibits cell proliferation in human gastric cancer cell line AGSObjective:To evaluate the effect of silencing USP22by small interfering RNA (siRNA) on the proliferation of gastric cancer AGS cells.Methods:Three USP22siRNAs and negative siRNA were designed and transfected into gastric cancer cells for48hours via Lipofectamine2000, respectively. Quantity real-time PCR (qRT-PCR) and western-blot were utilized to detect the expression levels of USP22mRNA and protein. The rates of cell proliferation and inhibition were measured by CCK8. The distribution of cell cycle was determined by flow cytometry.Results:Being transfected for48hours, all of three USP22siRNAs could silence the expression of USP22gene. Being transfected the USP22siRNA3for48hours, the expression levels of USP22mRNA and protein were reduced by80.47%±2.99%and79.40%±3.58%, respectively. The inhibition of cell proliferation was significant and the inhibitory rate was27.33%±3.49%. Moreover, the gastric cancer cells which stayed in G0/G1phase were increased significantly, while those stayed in S phase were decreased significantly.Conclusion:The USP22siRNA could inhibit the expression of USP22gene effectively and suppress the cell growth of gastric cancer cells significantly. |
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