结肠肿瘤细胞凋亡途径的研究及其在结肠癌靶向治疗中的可能性

目的观察两种结肠肿瘤细胞的凋亡途径哪种更为重要,并探讨其今后用于靶向治疗的可能性。方法应用免疫组织化学Max VisionTM快捷法检测外源性途径促凋亡蛋白Fas配体（FasL）、Bid及原位分子杂交法检测内源性途径促凋亡蛋白细胞色素CmRNA（Cyt c）在结肠癌（肠癌组）、结肠腺瘤（腺瘤组）的表达及FasL、Bid在正常结肠黏膜（正常组）的表达。表达程度采用半定量积分法。并对其中4例结肠癌、6例结肠腺瘤及7例正常肠黏膜细胞线粒体观察超微结构改变。结果外源性途径凋亡检测显示当正常组和腺瘤组FasL的阳性表达率分别为50%、62.5%时,肠癌组仅达到16.07%,提示结肠癌时外源性凋亡途径不是主要途径。外源性途径促凋亡蛋白Bid参与凋亡活动时,其表达率在肠癌组为66.07%,也低于正常组的72.22%及腺瘤组的94.44%,差异有统计学意义。而内源性途径凋亡的促凋亡蛋白Cyt c检测发现,随分化程度升高表达率亦上升。低、中、高分化肠癌的表达率分别为87.5%（14/16）、93.9%（31/33）及100%（11/11）。肠癌线粒体的超微结构观察显示,Cyt c呈高表达者,肠癌组及正常组均为50%（2/4）,腺瘤组则为66.7%（4/6）。肠癌组细胞线粒体大小不一,分布不均,基质不均,嵴发育不良且分布不均,少数线粒体膜破裂。腺瘤组大部分细胞线粒体丰富、规则,呈卵圆形,大小较一致,嵴发育良好,但基质不均,少部分线粒体嵴有断裂。正常组细胞线粒体嵴发育良好,基质均匀,少部分线粒体嵴有断裂。结论结肠癌时内、外源性凋亡途径均存在,但以内源性途径凋亡为主;对于内源性途径凋亡在结肠癌时发生的病理、生理意义有待进一步研究。在此之前,采用内源性途径的靶向治疗,可能时机尚不够成熟。

The study of apoptosis pathway of colorectal cancer cells and the potential value of target treatment of colorectal cancer in future

Objective To understand which apoptosis pathway were more important in the course of colorectal cancer. Methods The colorectal specimens were collected from 60 cases of colorectal cancer patients （CRC group） , 18 cases of colorectal adenoma patients （CRA group） and 18 normal adults （control group）. All the specimens were examined by in situ hybridization and immunohistochemical Max VisionTM methods for both the extrinsic and intrinsic apoptosis pathway, the extrinsic pathway by examination the FasL, Bid and the intrinsic pathway by cytochrome C mRNA （Cty c）. Results The positive rate of FasL expression were 16.07% （9/56 cases） in colorectal cancer group （CRC- group） , 62.5% （11/18 cases） in normal adult （control group） and 50% （9/18 cases） in colorectal adenoma group （CRA group）. The positive rate of Bid expression were 66.07% （ 37/56 cases ） in CRC group, 72.22 % （13/18 caded in the colorectal cancer is mainly through the intrinsic apoptosis pathway （mitochondria mediated pathway）. Targeting treatment of intrinsic apoptosis is considered not without risk before the complete elucidation of the pathophysiology.