Effect of △Np73 silencing on 5-FU chemotherapy sensitivity in colon cancer cells

Objective To investigate the effect of small interfering RNA (siRNA) mediated silencing of △Np73 on 5-FU chemotherapy sensitivity in SW620 colocancer cells and provide new treatment approach for the colon cancer.Methods siRNAs were transfected into SW620 colon cancer cells.The expression of △Np73 was observed.Cell viability of colon cancer cells were measured by MTr assay and cell apoptosis was assessed with flow cytometry after treatment of control siRNA or △Np73 siRNA or combined with 5-FU,respectively.The tumorigenesis was assessed by injecting △Np73 siRNA or control siRNA transfeeted SW620 colon cancer cells into nude mice,followed by treatment with 5-FU in the tumors.Results △Np73 siRNA was able to strongly inhibit △Np73 expression,however,it did not inhibit the growth of cells.Combination treatment with △Np73 siRNA and 5-FU produced significant higher apoptotic cell(42.9%) as compared with those with 5-FU treatment(18.9%) alone or those with △Np73 siRNA(8.8%) alone.The treatment with 5-FU in the xenngrafts derived from △Np73 siRNA transfected SW620 cells in nude mice can inhibitor tumor growth significantly (t=15.32,P<0.05).Conclusion △Np73siRNAs can specifically repress the expression of △Np73.Thus it sensitizess the cells to 5-FU chemotherapy in colon cancer. Key words: Colonic neoplasms; RNA,small interfering; Fluomuracii; Nuclear proteins; Tumor suppressor proteins