肿瘤坏死因子相关凋亡诱导配体治疗肝细胞癌的研究

ANTITUMOR EFFECT OF TRAIL IN HUMAN HEPATOCELLULAR CARCINOMA

目的探讨肿瘤坏死因子相关凋亡诱导配体(TRAIL)与其受体在肝细胞肝癌(hepatocellularcarcinoma,HCC)中的表达及意义,及利用TRAIL对HCC的治疗作用。方法采用免疫组化技术及原位杂交方法分别检测了100例肝癌组织,100例癌旁组织,40例正常肝组织中TRAIL及TRAILR的表达,并结合临床资料进行分析;采用不同浓度TRAIL处理肝癌细胞株HepG2、SMMC7721,观察经药物处理前后肿瘤细胞的凋亡发生率。结果TRAIL在正常肝组织中无表达,癌旁组织中的表达明显高于癌组织。86例肝癌组织不表达诱捕受体DcR1(86%),55例肝癌组织不表达诱捕受体DcR2(55%),40例正常肝组织两种诱捕受体均有表达。肝癌组织中死亡受体为高表达,诱捕受体为低表达,正常肝组织则相反,两者间有显著差异性(P<0.05)。肝癌组织中死亡受体的表达与肿瘤的分化呈正相关(P<0.01),与肿瘤分级呈负相关(P<0.05),与病人的性别、年龄、AFP水平、肿瘤的大小以及是否转移无关。经TRAIL(100ng/ml)处理24h,肝癌细胞凋亡发生率约10%,而Jurkat细胞凋亡率达70%以上,胆管癌细胞QBC939凋亡发生率约50%。结论HCC时,TRAILR普遍表达,但存在受体类型的表达差异,其中DcR1大多缺失,这为利用TRAIL治疗HCC提供了理论依据,然而,单一的TRAIL治疗只能有限的诱导肝癌细胞HepG2、SMMC7721发生凋亡,HCC对TRAIL诱导的凋亡存在耐药现象。

Objective To evaluate the expression of TRAIL and TRAIL receptors(TRAILR) in human hepatocellular carcinoma (HCC) and investigate therapeutic potential of sTRAIL in HCC.Method Expressions of TRAIL and TRAILR were determined in 100 pieces of carcinoma tissues, 100 pieces of tissues adjoining the neoplastic area and 40 pieces of normal liver tissues using immunohistochemical method and in situ hybridization, analysed combining with the clinical documents of patients. Cellular effects of TRAIL in promoting apoptosis on HCC cell lines HepG2 and SMMC-7721 were analyzed after exposure to different concentration recombinant protein.Results Expressions of TRAIL in tissues adjoining the neoplastic area were higher than in cancer tissues; Analysis of 100 clinical HCC tissue samples revealed that 86 tumors did not express DcR1 and 55 tumors did not express DcR2,but both DcR were detectable in all of the normal liver tissues. High expression of DR and low expression of DcR in HCC tissue differenced with low expression of DR and high expression of DcR in the normal hepatic tissue(P<0.05). The expression of DR is positive correlated with HCC differentiation(P<0.01) and negative correlated with grade of HCC(P<0.05). No relationships were found between DR level and gender, age, level of AFP, tumor size or metastasis. Recombinant TRAIL (100ng/ml) alone was found to have a slight activity as it killed about 10% of HCC cells within 24h compared with killing over 70% of Jurkat cells and about 50% of human cholangiocarcinoma cell line QBC939. Conclusion TRAILR expression was prevalent in HCC and discrepancy of receptor types was exited.Loss of DcR1 may contribute to TAILR therapy to HCC.However, HCC cell are insensitive towards TRAIL-mediated apoptosis, suggesting the presence of mediators that inhibit the TRAIL-inducing apoptosis pathway in HCC and a limited therapeutic role for TRAIL as a single agent in HCC.