FasL基因表达对结直肠癌细胞肝转移影响的研究

目的　探讨FasL基因表达对结直肠癌细胞生物学行为的影响及在肝转移中的作用。方法　采用RT PCR方法检测大肠癌原发灶、癌旁肠黏膜、肝转移灶中FasL基因表达。用细胞转染方法 ,将FasLcDNA转染人直肠癌细胞HR 8348,采用四唑蓝法观测FasL表达对癌细胞生长抑制率及对5 FU、卡铂杀伤作用的影响。　结果　结直肠癌原发灶 (5 8例 )、癌旁肠黏膜 (5 8例 )、肝转移灶 (2 8例 )中FasL基因表达阳性率分别为 2 4 % (14 /5 8)、14 % (8/5 8)、10 0 % (2 8/2 8)。肝转移灶中FasL表达阳性率高于癌原发灶 (χ2 =4 3 4 9,P <0 0 1)和癌旁肠黏膜组织 (χ2 =5 7 6 6 ,P <0 0 1)。肝转移组原发灶FasL表达阳性率高于无肝转移组 (χ2 =3 96 ,P <0 0 5 )。转染HR 8348细胞FasL表达为阳性。用 5 FU、卡铂杀伤FasL转染细胞和未转染细胞 ,2组癌细胞生长抑制率有显著性差异 (t=9 0 2、t=11 93,P <0 0 1)。在相同化疗药物浓度下 ,FasL阳性HR 8348细胞存活率高于对照组癌细胞。　结论　FasL阳性癌细胞对化疗药物有较强的耐受性。FasL基因表达能使癌细胞逃避免疫监视和杀伤并对化疗药物产生抗性 ,促进结直肠癌发生肝转移。

The influence of FasL gene expression upon hepatic metastasis of colorectal carcinoma

OBJECTIVE: To study FasL gene expression in colorectal carcinoma and its influences on biological behaviour of colorectal cancer and hepatic metastasis. METHODS: FasL gene expressions were examined with RT-PCR technique in the primary locus of colorectal cancer, mucosa adjacent to cancer, and hepatic metastasis. HR-8348 cells of human rectal cancer cell line were transfected with FasL cDNA. Cell growth suppression rates and cell response to 5-FU and carboplatin were observed and analysed with MTT method. RESULTS: FasL gene expressions were detected in the primary site of colorectal cancer (n = 58), cancer adjacent mucosa (n = 58), and hepatic metastasis (n = 28). The positive rate of FasL expression was 24% (14/58), 14% (8/58), 100% (28/28), respectively, in primary site, tumor adjacent mucoca and hepatic metastasis. FasL expression rate in hepatic metastasis was higher than that in the primary site (chi2 = 43.49, P < 0.01) and tumor adjacent mucosa (chi2 = 57.66, P < 0.01). In a group of patients with hepatic metastasis, FasL expression rate in primary site was higher than that in patients without hepatic metastasis (chi2 = 3.96, P < 0.05). In vitro experiment, positive expression of FasL was found in transfected HR-8348 cells. When 5-FU or carboplatin was added, there was a significant difference in growth suppression rate between FasL positive and control cancer cells (t = 9.02, t = 11.93, P < 0.01). Under same concentration of chemotheraputic agent, survival rate of FasL positive HR-8348 cells was higher than that of control cells. CONCLUSIONS: FasL positive cancer cells have more powerful resistance to chemotheraputic drugs. Expression of FasL gene in colorectal cancer cells is related with immune evasion to escape killing by immune cells, showing stronger drug-resistance, and it facilitates hepatic metastasis.