HPV16感染致MIR17HG表达失调驱动子宫颈上皮细胞恶性转化的分子机制

The malignant transformation of cervical epithelial cells caused by chronic persistent HR-HPV infection experiences three phases of latent, productive, and transforming infection, and the latter two phases can result in LSIL and HSIL, respectively. The diffuse expression of p16INK4a is a crucial molecular marker for identification and diagnosis of HSIL. How to inhibit the transformation of LSIL to HSIL is a challenge for precise treatment of the disease. We have sequenced the lncRNA expression profiles with microtissues from HSIL and LSIL by laser capture microdissection and found that the expression of a powerful cancer gene MIR17HG has been significantly increased. Furthermore, MIR17HG is regulated by E6 and E7, and can initiate the expression of p16INK4a. We speculate that MIR17HG induces cell malignant transformation during HR-HPV transforming infection phase. We plan to explore the molecular mechanisms of malignant transformation of cervical epithelial cells due to HPV16 infection; particularly, how the expression levels of MIR17HG are upregulated, and then how MIR17HG contributes to the induced expression of p16. We will explore the anti-tumorigenesis effects by MIR17HG siRNAs coated with nanoparticles on tumor xerographs in nude mice. We hope to provide novel insights in the prevention and therapy of cervical cancer and precancerous lesions.

高危型人乳头瘤病毒（HR-HPV）慢性持续性感染致细胞恶性转化经历了潜伏、分泌、转化三个阶段，后两者分别导致低级别和高级别上皮内病变（即LSIL、HSIL），且p16INK4a的弥漫表达是鉴别诊断HSIL的核心分子标识。如何遏制LSIL向HSIL转化依然是目前精准治疗的难题。我们采用激光捕获显微切割技术获得HSIL及LSIL微量组织进行lncRNA测序，发现HSIL组织中强效致癌基因MIR17HG显著升高；并研究发现，MIR17HG的表达不仅被E6、E7调控，还启动了p16INK4a的表达；推测HR-HPV转化感染阶段MIR17HG的升高驱动了细胞转化。本课题拟解析HPV16感染过程中MIR17HG表达上调并调控p16表达启动细胞恶性转化的分子机理；利用小鼠肿瘤模型探讨纳米材料包裹的MIR17HGsiRNAs阻断并逆转细胞转化的抗肿瘤形成作用；旨在为子宫颈癌及癌前病变的防治提供新思路。

本课题通过生物信息学方法、表型验证阐明了HPV16 调控MIR17HG 基因网络的分子机制：HPV16表达的病毒癌蛋白E6、E7显著下调ΔNp63α mRNA的转录水平，而ΔNp63α通过直接调控ZNF385B 和 CLDN1的转录水平抑制肿瘤细胞的生长，通过下调NFATC1抑制铂类耐药；进一步挖掘发现ΔNp63α调控39个lncRNAs表达谱，并确证ΔNp63α直接转录调控的lncRNA PART1、MIR17HG分别是与子宫颈癌细胞恶性生物学行为显著相关的非编码RNA。通过体内外试验阐明了新lncRNA PART1的抑制子宫颈癌细胞生长及侵袭的分子机制；解析了MIR17HG促进肿瘤细胞生长、侵袭、转移的作用，其调控分子机制依赖于下游调控的miRNAs：miR-17-3p、miR-17-5p、miR-18a-3p、miR-18a-5p、miR-19a-3p、miR-19b-3p、miR-19b-5p、miR-92a-3p、miR-92a-1-5p。HPV感染的临床标本中，与CIN1相比，CIN2-3组织中p16蛋白弥漫性表达，癌组织中表达显著升高，推测其机制可能是与MIR17HG结合的RBP蛋白HuR通过调控ΔNp63α 及p16转录因子mRNA稳定性而间接调控p16的表达水平。课题组同时初步探索了HPV的持续感染与BV感染正相关，而柯氏动弯杆菌是BV反复复发的主要原因，提出了治疗HPV感染需要先恢复阴道微生态稳态后抗病毒的理念。本课题期间共发表SCI文章14篇，中文核心期刊2篇; 培养博士4名、硕士12名; 授权软件专著权1项、发明专利公开3项、获2020年安徽省科技进步一等奖1项; 主持省级会议2次、参加国际、国内学术交流活动7次。授予人才称号包括安徽省特支计划卫生创新领军人才、安徽省学术和技术带头人。延续申请国家自然科学基金面上课题1项、安徽省重点研发项目1项。