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.
ABSTRACT
Objective To study the expression levels of interlukin-18(IL-18) in the CA1 region of the hippocampus and habenular of the rats with chronic stress. Methods Male Wistar rats (n = 30) weighting about 185～255g were divided into test group (T, n = 15) and control group (C, n = 15) randomly. The rats in group T were exposed to various types of stresses every day for consecutive 21 days. The rats in group C did not receive any stress during 21 days. Weighting and open-field tests were carried out on each rat before the test and on the 22nd day. On the 22nd day, brains were removed and cut coronally. Immunohistochemistry method was used to measure the expression levels of IL-18. Results After 21 -day stress, the body weight, erection time, rearing times, horizontal crossing numbers,modifying times and defecation in group T((297.33 ±25.83)g,(5.14 ±2.02)s,(19.00 ± 9.01), (9.47 ±3.64),(3. 93 ± 1. 87)and(4. 93 ± 1. 94)) were significantly different from those of group C((322.00 ±30.34)g,(1.97 ±0.93)s,(39.80 ±18.58),(14.80 ±5.88),(7.27 ±2.87)and(1.93 ±1.16)) (P < 0.01, P < 0.05). The average optical density values of IL-18 positive cells in CA1 region and habenular in group T ((0.3923 ±0.0084 and 0.4577 ±0.0234)) were higher than that in group C ((0. 3165 ±0.0063 and 0. 3400 ±0.0097)) (P<0.01). Conclusion The expression levels of IL-18 of the hippocampus glial cells and of the habenular neurons in the rats is increase after the chronic stress.