IL-18 over-expression inhibits proliferation of human colorectal cancer HCT-116 cells / 中国肿瘤生物治疗杂志

ABSTRACT

@#[Abstract] Objective: To investigate the effects of interleukin-18 over-expression on the in vitro and in vivo proliferation of human colorectal cancer (CRC) HCT-116 cells. Methods: A recombinant lentivirus vector containing human IL-18 gene fragment was constructed. Then theCRC HCT-116 cell line stably expressing human IL-18 (HCT-116/IL-18) was obtained by recombinant lentivirus transfection. In vitro proliferation of HCT-116/IL-18 cells and wild-type HCT-116 cells was determined by CCK-8 method. The expressions of IL-18, Cyclin D1, proliferating cell nuclear antigen (PCNA) and DNA damage repair enzyme (PARP) were detected by Western blotting. HCT-116 and HCT-116/IL-18 cells were inoculated into left and right axillas of Balb/c nude mice, respectively. Then the tumorigenicity and the growth of transplanted tumor were observed. The expressions of IL-18 and PCNAin xenograft tissues were detected by immunohistochemistry analysis. Results: IL-18 gene over-expression in HCT-116 cells could delay the proliferation of HCT-116 cells (P<0.05 or P<0.01). PARP expression was increased significantly and PCNA, Cyclin D1 expression were decreased in HCT-116/ IL-18 cells as compared to that of HCT-116 cells (P<0.01).The tumorigenicity of HCT-116/IL-18 cell was significantly decreased in nude mice with a tumor-formation rate of 43%; Compared with control group, HCT-116/IL-18cell line had a longer tumorigensis time, slower growth and smaller tumor volume; moreover, PCNAprotein expression was down-regulated in HCT-116/IL-18 xenograft tissuesas shown by immunohistochemistry analysis (P<0.01). Conclusion: IL-18 over-expression inhibited the growth and proliferation of HCT-116 cells both in vitro and in vivo, and the mechanism might berelated with IL-18 regulating cell cycle and promoting DNA damage.