ABSTRACT
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.
ABSTRACT
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 γ H2AX 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.
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Objective@#To investigate the effect and mechanism of LncRNA ANRIL on the radiosensitivity of HCT116 cells line and nude mouse transplant tumors.@*Methods@#The expression of LncRNA ANRIL in colorectal cancer cells was detected by qPCR. The negative control siRNA, ANRIL siRNA, miR-NC mimic, miR-195 mimic, miR-NC inhibitor and miR-195 inhibitor were transfected into HCT116 cells, and marked as negative control group, silencing ANRIL group, overexpressing miR-NC group, overexpressing miR-195 group, inhibiting miR-NC group and inhibiting miR-195 group, and the HCT116 cells without any treatment were marked as the blank control group. The clone formation assay was used to detect radiosensitivity of colorectal cancer cells, flow cytometry was used to detect apoptosis. The web site, StarBase, was used to predict the downstream miRNAs of ANRIL and dual luciferase reporter gene assay was used to further verify. Subcutaneous tumor transplantation assay was used to detect the effect of ANRIL on the growth of colorectal cancer cells after irradiation.@*Results@#After irradiation with 2, 4, 6 and 8 Gy, the cell survival fraction of silencing ANRIL group was significantly decreased when compared with that of negative control group (P<0.05), and the radiosensitivity ratio was 1.52. The apoptosis rate of the silencing ANRIL+ 4 Gy group was significantly higher than that of the negative control+ 4 Gy group ((27.86±2.78)% vs. (12.06±1.46)%, P<0.05). The results of the experiment on nude mouse transplant tumors showed that the tumor volume in the negative control group was lower than that of the silent ANRIL group on days 13, 16, 19, 22 and 25 ((234±66) mm3, (273±63) mm3, (296±72) mm3, (321±85) mm3 and (403±94) mm3 vs. (357±79) mm3, (485±124) mm3, (617±143) mm3, (764±174) mm3 and (985±221) mm3P<0.05). MiR-195 is a target gene of ANRIL, and inhibition of miR-195 can reverse the inhibitory effect of silencing ANRIL on radiosensitivity, apoptosis and xenografts of HCT116 cells.@*Conclusions@#LncRNA ANRIL regulates the radiosensitivity of colorectal cancer cells by miR-195, which may provide a new sensitizing target for clinical colorectal cancer radiotherapy.
ABSTRACT
Objective It has been known that NSAIDs can inhibit the growth of tumors through cyclooxygenase, but it is unknown that whether there are other mechanisms involved. It is essential to detect the effect of indomethacin for proliferation and apoptosis in the HCT116 and explore its anti tumor mechanism. Methods Human colon adenocarcinoma cell line HCT116 was treated with different concentration of indomethacin for 24 h and CDK 2,CDK 4, Bcl 2, Bax and p21 WAF1/CIP1 protein were detected by Western blot. Results Indomethacin down regulated the expression of CDK 2, CDK 4, Bcl 2 and up regulated the expression of p21 WAF1/CIP1 , however, the expression of Bax remained unchanged. Conclusions Inhibiting proliferation and inducing apoptosis contribute to the anti tumor activity of indomethacin by down regulating the expression of CDK 2, CDK 4, Bcl 2 and up regulating the expression of p21 WAF1/CIP1 .