Objective      To determine the expression of oral cancer overexpressed protein 1 (ORAOV1) in colon cancer tissue and investigate its effect of ORAOV1 on the proliferation

cell cycle and apoptosis in colon cancer cell lines.       Methods       The mRNA and protein levels of OVAOV1 in 6 tissue samples of human colon cancer and corresponding para-cancer tissues were detected by qRT-PCR and Western blotting. The expression of ORAOV1 in LoVo cells and SW480 cells was down-regulated by RNAi technique

and the interference results were confirmed by Western blotting. The proliferation of 2 colon cancer cell lines with different ORAOV1 expression levels was detected by CCK-8 assay. Cell cycle and apoptosis were analyzed by flow cytometry.       Results      The expression of ORAOV1 at mRNA and protein levels was significantly higher in the colon cancer tissues than the para-cancer tissues (P0.05). Western blotting indicated that the interference to ORAOV1 was successful in LoVo cells and SW480 cells. Compared with the cells with normal ORAOV1 expression

the proliferation of the cells with low ORAOV1 expression was inhibited. ORAOV1 interference increased the percentage of cells at S stage (P0.05) and early apoptotic ratio (P0.05).       Conclusion      Expression of ORAOV1 is increased in colon cancer

and the proliferation of colon cancer cells with ORAOV1 knockdown is inhibited through increasing the S stage arrest and early apoptosis.