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目的 研究端粒酶催化亚单位 (hTERT)和p5 3基因在大肠癌组织中的表达 ,进而探讨大肠癌发生过程中端粒酶活化的分子机制。方法 分别采用原位逆转录聚合酶链反应 (RT PCR)和端粒重复序列扩增 (TRAP)法检测 46例大肠癌及其相应正常组织中hTERTmRNA表达与端粒酶活性。用免疫组化S P法测定上述组织标本中的p5 3蛋白表达。结果 hTERTmRNA与端粒酶活性在大肠癌组织中阳性表达率分别为 87 0 % (4 0 /4 6)和 80 4% (3 7/4 6) ,均明显高于相应正常组织 (P <0 .0 1)。大肠癌中hTERYmRNA表达与端粒酶活性明显相关 (r=0 .696,P <0 .0 1)。p5 3蛋白在大肠癌中阳性表达率为 67 4% (3 1/4 6) ,而正常组织未见阳性表达 ,二者比较差异有显著性 (P <0 .0 1)。大肠癌组织p5 3蛋白表达与hTERTmRNA表达或端粒酶活性无显著相关性 (P >0 .0 5 )。结论 端粒酶激活与大肠癌的发生密切相关 ,hTERTmRNA表达上调可能在大肠癌端粒酶活性调节中发挥重要作用。p5 3蛋白表达增强可能与端粒酶激活无直接相关
Objective To study the expression of telomerase catalytic subunit (hTERT) and p5 3 gene in colorectal carcinoma and to explore the molecular mechanism of telomerase activation in colorectal carcinogenesis. Methods The expression of hTERT mRNA and telomerase activity in 46 cases of colorectal carcinoma and its corresponding normal tissues were detected by reverse transcription polymerase chain reaction (RT PCR) and telomeric repeat amplification (TRAP) respectively. Immunohistochemical SP method was used to determine the expression of p5 3 protein in the above tissue samples. Results The positive rates of hTERT mRNA and telomerase activity in colorectal cancer tissues were 87 0% (40/4 6) and 80 4% (3 7/4 6), respectively, which were significantly higher than those in corresponding normal tissues (P 0 .0 1). The expression of hTERY mRNA in colorectal cancer was significantly associated with telomerase activity (r = 0.696, P <0.01). The positive rate of p5-3 protein in colorectal cancer was 67 4% (3 1/4 6), while no expression was found in normal tissues. The difference was significant (P <0.01). There was no significant correlation between p5 3 protein expression and hTERT mRNA expression or telomerase activity in colorectal carcinoma (P> 0.05). Conclusion The activation of telomerase is closely related to the occurrence of colorectal cancer. The up-regulation of hTERT mRNA may play an important role in the regulation of telomerase activity in colorectal cancer. The increase of p5 3 protein expression may not be directly related to telomerase activation