卵巢癌细胞HLA Ⅰ类分子表达异常和TAP,LMP基因表达的关系

A Synchronistic Deficiency in Expression of HLA Class I Molecules and TAP/LMP Genes in Human Ovarian Cancer Cells

目的:肿瘤细胞表达MHCⅠ类分子是激发肿瘤抗原特异性CTL进行肿瘤免疫治疗的关键,肿瘤细胞HLAⅠ类分子表达异常是肿瘤逃脱免疫监视的重要机制.我们探讨了卵巢癌细胞HLAⅠ类分子表达异常的分子基础.方法:本文以West-ern blot、免疫组化和流式细胞术检测卵巢癌细胞HLA Ⅰ类分子的表达,以RT-PCR检测TAP,IMP基因的表达,探讨肿瘤细胞HLA Ⅰ类分子表达异常的分子基础.结果:卵巢癌中HLA Ⅰ类分子表达异常相当普遍(5/8),并涉及抗原加工相关基因TAP,LMP基因表达异常.25℃培养肿瘤细胞可部分诱导Ⅰ类分子的表达;结论:卵巢癌HLA Ⅰ类分子表达异常与其Ⅰ类抗原加工途径异常有关.

Objective: Full expression of class I HLA molecules on tumor cells is pivotal in priming the tumor antigen-specific CTLs for effective iramunotherapies. Tumor cells display abnonnal expression of HLA class I molecules in human ovarian carcinoma. Methods: In this study, the expression of class I molecules in human ovarian cancer cells was determined by using Western bloting, immunohistochemistry testing and flow cytometry. The mRNA of TAP (transporter associated with antigen processing) and LMP(low molecular weight polypeptide) were exannined at the same time by RT-PCR. Results: It has been shown that class I molecules were unable to be, or only weakly, expressed in five of eight ovarian cancer cell lines. On these cell lines abnormal in class I expression, no or only little mRNA were detected for TAP1, TAP2, LMP2 and(or) LMP7 genes. Class I expression, however, could be partially recovered by incubating the tumor cells at 25℃ when compared with those at 37℃ . Conclusion: The results suggested that the dysfunction of TAP and IMP genes, following by a defective expression of class I molecules, might be one of the mechanisms enable ovarian cancer cells to escape from immune surveillance.