生长抑素对大肠癌细胞凋亡的影响

目的 探讨生长抑素对大肠癌细胞凋亡的影响.方法 采用巢式RT-PCR方法检测2004年1月至2006年10月皖南医学院附属弋矶山医院收治的79例大肠癌患者癌组织中生长抑素mRNA的表达情况,采用免疫组织化学法检测大肠癌组织中生长抑素、Fas、FasL、半胱天冬蛋白酶(caspase)3和8蛋白的表达情况,TUNEL法检测细胞凋亡指数(AI).采用χ~2检验、q检验、Spearman等级相关检验对结果进行分析.结果 大肠癌组织中生长抑素mRNA与其蛋白表达呈正相关(r=0.98,P<0.05).低分化和中分化大肠癌组织中生长抑素mRNA及其蛋白的表达明显低于高分化组织(χ~2=10.78,11.24,5.27,5.24,P<0.05);生长抑素mRNA及其蛋白在乳头状腺癌的阳性表达率明显高于黏液腺癌+印戒细胞癌及未分化癌(χ~2=6.56,6.99,5.44,7.39,P<0.05);Dukes A、B期的生长抑素mRNA及其蛋白阳性表达率明显高于C、D期(χ~2=5.17,4.06,P<0.05).生长抑素高表达组、中表达组的AI明显高于低表达组(q=5.66,4.21,P<0.05);Fas、caspase-8、caspase-3在生长抑素高表达组、中表达组的阳性表达率明显高于低表达组(χ~2=5.48,5.62,6.89,4.32,4.19,3.91,P<0.05).结论 生长抑素对大肠癌细胞凋亡的调控可能与Fas/FasL基因的表达失衡、功能和信号系统的紊乱有关.

Effects of somatostatin on the apoptosis of colorectal cancer cells

Objective To investigate the effects of somatostatin on the apoptosis of colorectal cancer cells. Methods The expression of somatostatin mRNA in colorectal cancer tissues from 79 patients who had been admired to Yijishan Hospital from January 2004 to October 2006 was detected by nested RT-PCR. The apoptotic index of colorectal cancer cells was detected by TUNEL, and the protein expressions of somatostatin, Fas, FasL, caspase-3 and caspase-8 in colorectal cancer tissues were detected by immunohistochemistry. All data were analyzed by chi-square test, q test and Spearman rank correlation coefficient. Results There was a positive correlation between the mRNA and protein expression of somatostatin (r = 0.98, P < 0.05). The mRNA and protein expression of somatostatin in poorly and moderately differentiated colorectal cancers were significantly lower than that in well differentiated colorectal cancers (χ~2 = 10.78, 11.24, 5.27, 5.24, P < 0.05). The positive expression rates of mRNA and protein of somatostatin in papillary adenocarcinoma were significantly higher than those in mucinous adenocarcinoma and signet ring cell carcinoma and undifferentiated carcinoma (χ~2= 6.56, 6.99, 5.44, 7.39, P < 0.05). The mRNA and protein expression of somatostatin in colorectal cancer in Dukes A and B were significantly higher than that in Dukes C and D (χ~2 =5.17, 4.06, P <0.05). The apoptotic index in high or moderate somatostatin expression group was significantly higher than that in low somatostain expression group (q = 5.66, 4.21, P < 0.05), and the positive expression rates of Fas, caspase-8 and caspase-3 in high or moderate somatostatin expression group were significantly higher than those in low somatostafin expression group (χ~2= 5.48, 5.62, 6.89, 4.32, 4.19, 3.91, P <0.05). Conclusion Somatostatin plays an important role in the regulation of cell apoptosis in colorectal cancer, and the mechanism may be related to the aberrant expression of Fas/FasL.