NF-kB抑制LPTS的分子机制及其在HPV16促进宫颈癌端粒酶活性中作用的研究

The abmormal enhancement of telomerase activity is associated with the carcinogenesis and development of cervical cancer. Previous reports have shown that LPTS is a telomerase inhibitor.The E6 oncoprotein of human papillomavirus 16 type (HPV16 E6) can both activate NF-kB and enhance telomerase activity, however, it is unclear whether there is relationship between the two events. Our preliminary results showed that there are possible binding sites of NF-kB in 5＇regulatory region of LPTS gene.The expression of HPV16 E6 can downregulate LPTS besides activating NF-kB. Treatment with the inhibitor of NF-kB resulted in the upregualtion of LPTS. In the present study, we will identify the exact binding sites of NF-kB in the 5′flanking region of LPTS gene and further confirm that LPTS is a novel target gene of NF-kB. Subsequently, we will clarify that HPV16 E6 suppress LPTS expression through activating NF-kB, which is a novel mechanism in HPV16 E6-mediated total enhancement of telomerase activity in cervical cancer. Moreover, we will elucidate the role of this novel mechanism in HPV16 E6-mediated total enhancement of telomerase activity. The anticipated results of the present study may provide novel detail for exploring the relationship between HPV16 E6 and the increasement of telomerase activity, and may pave a way for designing novel strategy to prevent and treat cervical cancer by targeting the novel pathway“HPVE6→NF-kB activation→LPTS downregulation→enhancement of telomerase activity”.

端粒酶活性的异常升高与宫颈癌的发生发展密切相关，LPTS是端粒酶的抑制分子。HPV16 E6的表达既可激活NF-kB，又可促进端粒酶活性，但两者之间有无关联尚不清楚。我们前期发现，在LPTS基因5＇调控区存在NF-kB预测结合位点；而E6的表达可激活NF-kB，并下调LPTS表达；在用NF-kB抑制剂处理细胞后，可上调LPTS的表达。基于此，本项目拟首先确定NF-kB在LPTS基因5＇调控区中的具体结合位点，率先证实LPTS是LPTS的新靶基因，进而明确“HPV16E6→活化NF-kB→LPTS下调”通路是HPV16 E6促端粒酶活性的一个新机制，并阐明该新机制在HPV16E6总体促端粒酶活性作用中的重要性，为全面揭示HPV16E6与端粒酶活性的关系提供新的理论资料，并为探索针对“HPV16E6→活化NF-kB→LPTS下调→端粒酶活性升高”这一全新通路的宫颈癌防治新策略提供科学依据。

端粒酶活性的异常升高与宫颈癌的发生发展密切相关，LPTS是端粒酶的抑制分子。HPV16 E6的表达既可激活NF-κB，又可促进端粒酶活性，但两者之间有无关联尚不清楚。我们前期发现，在LPTS基因5＇调控区存在NF-κB预测结合位点；而E6的表达可激活NF-κB，并下调LPTS表达；在用NF-κB抑制剂处理细胞后，可上调LPTS的表达。基于此，本项目拟首先确定NF-κB在LPTS基因5＇调控区中的具体结合位点，率先证实LPTS是LPTS的新靶基因，进而明确“HPV16E6→活化NF-κB→LPTS下调”通路是HPV16 E6促端粒酶活性的一个新机制，并阐明该新机制在HPV16E6总体促端粒酶活性作用中的重要性，为全面揭示HPV16E6与端粒酶活性的关系提供新的理论资料，并为探索针对“HPV16E6→活化NF-κB→LPTS下调→端粒酶活性升高”这一全新通路的宫颈癌防治新策略提供科学依据。在本项目资助下，我们率先证实了NF-κB可在mRNA及蛋白水平抑制LPTS基因的表达。ChIP及EMSA实验证实NF-κB p65可直接结合于人LPTS基因5'非翻译区的-1143/-1136及-888/-881位点。如上位点的突变，可解除p65对LPTS表达活性的抑制作用。进一步，我们还构建了宫颈癌及直肠癌的移植瘤模型，验证了p65-LPTS对癌细胞增殖及肿瘤生长的调控作用。最后，我们还在网上查阅了肿瘤样本数据库，进一步验证了p65与LPTS表达的相关性。总之，我们的研究表明：干预p65-LPTS，可能成为治疗炎性相关肿瘤的重要策略。