HPV E7抑制LSD1促进宫颈癌细胞EMT的机制研究

Recently, it has been shown that epithelial mesenchynaltransition （EMT）of cervical cancer cells is the possible mechanism underlying their malignant behaviour induced by HPV. We have found HPV E7 gene affected the proliferation, invasion and migration through TGFβ1/smad3 pathway, which could induce EMT of HPV positive cervical cancer cells accompanied by the down-regulation of LSD1. In previous literatures, LSD1 has been identified as vital epigenetic determinant at the level of transcription regulation,and proved to be a key factor of EMT transition. On the basis of these findings, we postulated that EMT transition involved by LSD1 may be an important mechanism of HPV E7-induced cervical cancer. Furthermore, we noted that E7/LSD1/CoREST compounded molecule was the basic regulation spot. However, it is still unclear of underlying mechanism of interaction between E7 gene and LSD1/CoREST. In addition, it is worthy of detailed exploration for LSD1 function in these effections. Therefore, our research group attempt to focus on HPV E7 gene, and inspect the possible mechanism of HPV E7-induced EMT when LSD1 being downregulated, as well as the downstream signals using ChIP, peptide chip and tissue microarray techniques via gene overexpression or silence.

新近研究表明，宫颈癌上皮-间叶转化（EMT）可能是HPV介导宫颈癌发病的关键机制。我们前期发现，HPV E7基因经TGFβ1/smad3途径影响宫颈癌细胞的增殖、侵袭和转移，而TGFβ1可诱导HPV阳性宫颈癌细胞发生EMT，同时伴随LSD1表达下调。LSD1被认为是调控肿瘤基因转录的重要表观遗传学因子，并证实肿瘤细胞EMT依赖于LSD1。因此我们推测，在HPV介导的宫颈癌发生过程中，LSD1参与的EMT是关键机制之一。进一步实验表明，HPV E7/LSD1/CoREST复合物确为宫颈癌细胞EMT中的关键分子，但E7基因与LSD1/CoREST复合物作用的机制尚不清楚，LSD1是否是其中的必须分子也有待继续研究。为此，课题组针对HPV E7基因，拟通过双向基因调控，采用ChIP、多肽芯片和组织芯片等技术，探索HPV E7抑制LSD1促进EMT的机制，并验证其关键效应分子。

本项研究通过研究HPV致癌基因E7对其它致癌基因LSD1的调控作用，来深入探讨LSD1对宫颈癌发生EMT的作用影响和分子机制。我们发现LSD1在宫颈癌组织中表达明显高于正常组织，并且可以分别在体内体外实验中促进宫颈癌细胞的侵袭转移能力。HPV16 E7可以促进LSD1的蛋白表达，LSD1在Vimentin启动子上发生组蛋白甲脱基化，从而促进Vimentin表达，继而促进宫颈癌细胞的侵袭转移能力。通过以上研究我们可以分别针对LSD1的基因敲除和抑制剂来抑制LSD1的表达和功能，继而避开HPV的致癌基因来抑制宫颈癌细胞的侵袭转移。