Experimental Study Of The Treatment On Colorectal Carcinoma By RNAi Of Survivin In Vitro And In Vivo

Partâ… Experimental study of the treatment on colorectal carcinoma by RNAi of survivin in vitroObjective: To explore the effects of siRNA targeting survivin on human carcinoma cells SW480 in vitro.Methods: The human colorectal carcinoma cell line SW480 was treated with siRNA targeting survivin. The expression level of survivin in transfected SW480 cells was detected by RT-PCR and immunocytochemistry. The effects of siRNA on cell cycle were analyzed by FCM with PI staining. 5-Fu and radiotherapy were combined with siRNAs targeting survivin to study the sensitivity of SW480 induced by siRNA targeting survivin to chemotherapy and radiotherapy. The effects of the survivin siRNA combined with 5-Fu or radiotherapy on the growth of SW480 were studied by MTT assay. The apoptosis rate of SW480 was analyzed by FCM with annexinV/PI staining.Results: RT-PCR demonstrated that the expression of survivin was knocked down significantly by the siRNA. Arrest in G2/M phase of the cell cycle was detected by FCM in the SW480 cells transfected with siRNA targeting survivin. The MTT assay showed that siRNA targeting survivin with 5-Fu or radiotherapy inhibited the growth of SW480 cells more significantly compare with single treatment. More apoptosis cells were detected by FCM in the SW480 cells treated with siRNA combined with 5-Fu or radiotherapy. Conclusions: We can inhibit survivin of the human colorectal carcinoma cell line SW480 with small interfering RNA. The siRNA targeting survivin combined with radiotherapy or 5-Fu inhibited the proliferation of SW480 and increased the percentage of apoptotic cells markedly. The siRNA targeting survivin can enhance the sensitivity of colorectal carcinoma cell line SW480 to chemotherapy and radiotherapy in vitro.Partâ…¡Experimental study of the treatment on colorectal carcinoma by RNAi of survivin in vivoObjective: To explore the effects of siRNA targeting survivin on human carcinoma cells SW480 in vivo.Methods: Nude mice colorectal cainoma model was established by injection with colorectal carcinoma cell line SW480 subcutaneouly. The nude mice were injected with siRNA intratumoraly or combined with radiotherapy. The tumor was measured by caliper and the volume was calculated according to the formula V=1/6Ï€ab2. The mice were executed and the tumor was dissected in the end of the treatment. The tumor was detected by immunohistochemistry and TUNEL assay.Results: The tumor of the nude mice which were treated with the siRNA targeting survivin combined with radiotherapy grew more slowly compare with single treatment. The expression of survivin was down-regulatied markedly in the tumor of the mice which were treated with siRNA targeting survivin , the expression of caspase-3 and bax increased most significantly in the mice which were treated with survivin siRNA combined with radiotherapy. The TUNEL assay demonstated that the tumor of the mice treated with survivin siRNA combined with radiotherapy has more positive cells.Conclusions: We can inhibit survivin of the human colorectal carcinoma model with small interfering RNA. The siRNA targeting survivin combined with radiotherapy inhibited tumor growth significantly. The siRNA targeting survivin combined with radiotherapy up-regulated caspase-3,bax and increased the apoptotic cells in the tumor markedly. The siRNA targeting survivin can enhance the sensitivity of colorectal carcinoma cell line SW480 to radiotherapy in vivo.