Effect Of Transfected DPC4 Gene On Angiogenesis Of Colon Carcinoma

Objective:To study the mechanism of transfected DPC4 gene on angiogenesis and growth suppression in human colon carcinoma .Methods:SW620 cells, a human colorectal carcinoma cell line, were transfected with PcDNA3.1-DPC4 plasmid using lipofectamine transfecting technique. Expressing Smad4 in DPC4+-SW620 cells was observed by Immunohistochemistry( SP method) and Western blot. The expression of VEGF protein in the cell supernatant was detected by ELISA, VEGF mRNA by RT-PCR. The model of nude mice inoculated with DPC4+-SW620 cells was established by injecting into flank subcutaneously.The expression of VEGF protein and the microvessel density of tumor tissue in nude mice were detected by Immunohistochemistry( SP method).Results:1. DPC4+-SW620 cells expressing Smad4 were harvested.2. Smad4 Protein showed stronger expression in SW620 cells transfected with PcDNA-DPC4 plasmid than that in not-transfected SW620 cells and SW620 cells transfected with blank plasmid, and the positive signal was localized in cytoplasm and nucleus, mainly in cytoplasm.3. There were lower expressions of VEGF protein and mRNA in DPC4' - SW620 cells than in SW620 cells and PcDNA-SW620 cells(P<0.05).4. The model of nude mice inoculated with colon carcinoma cells was established successfully. The tumors of nude mice inoculated with DPC4-SW620 cells growed more slowly than that inoculated with SW620 cells and PcDNA-SW620 cells. The volume and weight of tumors in nude mice inoculated with DPC4 ' ~sw620 cells were smaller than that with sw620 cells and PcDNA-sw620 cells(P<0.05).5. The expressions of VEGF and the microvessel density in DPC4' -SW620 cells were lower than that in SW620 cells and PcDNA-SW620 cells(p<0.05).Conclusions:1 .The DPC4 gene can suppress the tumors of nude mice inoculated with DPC4 + -SW620 cells.2.The inhibition effect of DPC4 on colon carcinoma may be partly mediated by suppressing angiogenesis of tumor.