中文摘要：

目的探讨fat-1基因在结肠癌HT-29细胞凋亡、增殖以及细胞周期中所起的作用。方法构建真核表达载体（pEGFP—fat-1），用脂质体介导的方法转染到结肠癌HT-29细胞，通过荧光显微镜观察及RT-PCR检测fat-1基因的表达，气相色谱分析检测fat-1基因对HT-29细胞n-6／n-3多聚不饱和脂肪酸（PUFAs）比例的影响，MTT法分析fat-1基因对HT-29细胞增殖的影响，流式细胞术检测fat-1基因对HT-29细胞凋亡和细胞周期的影响。结果成功构建了真核表达载体pEGFP—fat-1，并在HT-29细胞内有效表达。fat-1基因通过降低HT-29细胞内n-6／n-3PUFAs的比例抑制HT-29细胞的增殖，促进其凋亡，细胞增殖主要被阻滞在S期。结论fat-1基因改变HT-29细胞n-6／n-3PUFAs比例后，通过一定的信号转导途径促进大部分HT-29细胞在S期凋亡，抑制了其增殖。

英文摘要：

Objective To investigate the effect of fat-1 gene encoding n-3 fatty acid desaturase on the proliferation and apoptosis of colon cancer cell HT-29. Methods fat-1 gene was transfected into HT-29 cells by liposomal reagent. The expression of fat-1 gene was detected by fluorescent micrographs and RT-PCR. Gas chromatography, MTT and flow cytometry were used to examine the change in n-6/ n-3 PUFAs ratio, proliferation, cell cycle and apoptosis, respectively. Results After transfection of fat-1 gene, n-6/n-3 PUFAs ratio decreased significantly. Apoptosis of HT-29 cells was induced and cell cycle was changed. Apoptosis mainly appeared in the synthesis phase. Conclusion fat-1 gene encoding n-3 fatty acid desaturase can significantly decrease n-6/n-3 ratio. Consequently, apoptosis was triggered and cell cycle was changed. Tranfection of fat-1 gene into HT-29 cells may be a new potential treatment for colon cancer.