Objective: To evaluate the effect and mechanism of down-regulating the expression of REV7 on the radiosensitivity of human colon cancer cell HCT116. Methods: HCT116 cells were cultured and the expression of REV7 was down-regulated by RNA interference technique. HCT116 cells were divided into the blank group, negative control transfected with negative RNA oligo group and REV7 expression down-regulation transfected with REV7 RNA oligo group, respectively. The cell proliferation was determined by colony formation assay. The expression levels of the proteins of relevant genes were detected by Western blot. The level of cell apoptosis and non-homologous end joining was evaluated. Results: The colony formation rate was significantly reduced in THE REV7 siRNA group after 6Gy irradiation (P<0.05). The down-regulating efficiency rate of REV7 gene was>60% in the REV7 siRNA group. The expression levels of γH₂AX and Caspase9 were significantly up-regulated, whereas those of KU80 and XRCC4 were remarkably down-regulated in the REV7 siRNA group (all P<0.05). Conclusions The radiosensitivity of human colon cancer cell HCT116 can be increased by down-regulating the expression of REV7. The underlying mechanism may be related to the lower incidence rate of non-homologous end joining.

OBJECTIVE: This study aimed to explore the influence of Rce1 on invasion and migration of tongue squamous cell carcinoma cells by silencing the Rce1 gene with RNA interference. METHODS: The tongue squamous cell carcinoma Cal-27 and SCC-4 cells were cultured in vitro. The small interfering RNA (siRNA) of the Rce1 gene was designed, and the Rcel gene expression was silenced vialiposome transfection. According to the siRNA transfected by liposome, the experimental group was divided into three groups, namely, Rce1-siRNA-1, Rce1-siRNA-2, and Rce1-siRNA-3 groups. Negative control group was transfected by siCON, and the blank control group was untransfected by siRNA. The Rce1, RhoA, and K-Ras gene expression levels in each group were analyzed by real-time quantitative polymerase chain reaction. The Rce1, RhoA, K-Ras, MMP-2, and MMP-9 protein expression levels were analyzed by Western blot. The invasiveness of tongue cancer cell Cal-27 and SCC-4 were determined by Transwell invasion assay, and cell migration assay was performed by cell scratch assay. RESULTS: Real-time quantitative polymerase chain reaction and Western blot results showed that compared with the negative and blank control groups, the Rce1 gene and protein expression levels in three experimental groups decreased (P<0.05). The RhoA, K-Ras gene and protein expression levels were insignificantly different among groups (P>0.05). Meanwhile, the MMP-2 and MMP-9 expression levels decreased (P<0.05). Transwell invasion assay results showed that the total number of cells in the PET film of the experimental groups was significantly decreased compared with the control group (P<0.05). The cell scratch test showed that the cell closure time of the scratch in the interference group was significantly longer than those in the control and blank groups (P<0.05). CONCLUSIONS Silencing Rce1 in vitro can effectively downregulate its expression in tongue squamous cell carcinoma cells Cal-27 and SCC-4 and reduce the migration and invasion abilities of these cells.
Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Endopeptidases ; metabolism ; Humans ; Neoplasm Invasiveness ; RNA Interference ; RNA, Small Interfering ; Tongue Neoplasms ; metabolism ; therapy ; Transfection