端粒酶调节相关基因TRAP与肿瘤生物学特性的关系

目的：研究TRAP基因在人肿瘤组织中的表达及其与人端粒酶逆转录酶(hTERT)的作用相关性，探讨其在人肿瘤发生中的作用。方法：通过原核表达TRAP蛋白免疫新西兰白兔，制备特异性多克隆抗体；免疫组化检测TRAP及hTERT在人肿瘤组织中的表达；通过构建TRAP真核表达载体、基因转染，观察TRAP对细胞hTERT转录、端粒酶活性和癌细胞生长及成瘤性的影响。结果：通过大肠杆菌表达的TRAP蛋白免疫、制备多克隆抗体，经Westem blot鉴定与TRAP具有特异结合性；免疫组化显示247例恶性肿瘤中有213例TRAP阳性，表达率为86．2％，而在所有癌旁组织中TRAP为阴性。另外，交界性及癌前病变与良性病变组织中TRAP表达差异也有显著性：进一步检测卵巢生发上皮肿瘤、乳腺癌、肝癌及中枢神经系统肿瘤组织hTERT表达，显示hTERT与TRAP表达的结果相一致。TRAP正义转染使hTERT及端粒酶活性升高，细胞增殖加快；而反义转染时，两者均下降，细胞增殖受抑。裸鼠成瘤性实验表明：正义TRAP使癌细胞成瘤性增强，而反义则抑制移植瘤的生长。结论：TRAP表达存在于人癌组织及部分癌前病变，与癌细胞恶性表型相关，并与hTERT表达一致。TRAP基因参与对端粒酶的调节作用，可能与人肿瘤发生有关。

Characterization of telomerase regulation association gene TRAP and cancer biology

Objective: To investigate expression of TRAP in human tumors and correlativity between TRAP and hTERT and to explore the role of TRAP in tumorigenesis. Methods: TRAP was expressed in E.coli . and polyclonal antibody was prepared by immunization of New Zealand rabbits. Expressions of TRAP gene and hTERT in human tumors were analyzed by immunohistochemistry. The eukaryotic expression vectors of TRAP were constructed and transferred stably into HeLa cells to be analysed with Northern blot, TRAP PCR ELISA, growth curve, nude mouse transplantation. Results: Polyclonal antibody was obtained from New Zealand rabbits immunized with TRAP fuse protein, which was inducibly expressed in E.coli ., and its specificity was verified in Western blot. TRAP staining was detected in 213 (86.2%)of 247 malignant tumors. On the contrary, TRAP in all tissues adjacent to tumors was negative.There is a obvious difference between borderline,pre cancerous and benign lesion in the expression of TRAP.Furthermore, hTERT staining was conducted and its result was consistent with that of TRAP. Up regulation and down regulation of hTERT expression and telomerase activity were observed respectively in HeLa cells transfected stably with sense and antisence TRAP recombination. Increased proliferation presented in the former and growth inhibition in the latter. Besides, in nude mice, tumorigenecity of sense TRAP transfected HeLa cells was enhanced while tumor growth of antisense TRAP transfected HeLa cells was retarded. Conclusion: The expression of TRAP, which could be detected in most of human cancers and part of pre cancerous lesions, was correlated with expression of hTERT. The status of TRAP expression could regulate telomerase activity and present effects on growth and tumorigeneity of cancer cells. This suggests that TRAP is involved in human tumorigenesis through regulation of telermarase activity.