STAT3/WDHD1/GCN5通路调控HPV-E7表达细胞逃避G1检验点的机制研究

Human papillomaviruses (HPV) are the causative agents for the development of cervical cancer. The prophylactic vaccines are not effective for patients who have been infected or immunosuppressed and there has no specific drugs for HPV infection. Therefore, it is important to further elucidate the mechanism of carcinogenesis of HPV. The E7 oncoprotein of high-risk HPV abrogates the G1 cell cycle checkpoint and induces genomic instability but the mechanism is not fully understood. A recent article by the applicant suggested that WDHD1 can regulate the G1 checkpoint of E7 expressing cells by a mechanism independent of DNA replication initiation. Our preliminary data showed that GCN5 was highly expressed in E7 expressing cells and its expression was regulated by WDHD1. It is known that GCN5 is involved in the regulation of G1 checkpoint. Therefore we inferred that WDHD1 facilitates G1 checkpoint abrogation in E7 expressing cells by modulating GCN5.Moreover, ChIP assays were performed and founda significant increase in STAT3 bound to the wdhd1 promoter. This indicates that WDHD1 gene as a STAT3 new target and STAT3 plays a role in DNA replication by regulating WDHD1.We proposed the following research objectives: (1)To elucidate the role of GCN5 in the regulation of G1 checkpoint by WDHD1 in E7 expressing cells; (2) To reveal the role and mechanism of STAT3 in regulating WDHD1 in E7 cells. These studies shed light on the mechanisms by which HPV induces genomic instability and have therapeutic implications.

人乳头瘤病毒（HPV）感染是宫颈癌发生的主要诱因。预防性疫苗对已感染或免疫抑制病人无效，且临床尚无特异性药物，因此深入探讨高危型HPV的致癌机制仍具有重要的临床意义。HPV早期基因E7可使G1检验点失活，进而诱导基因组不稳定及癌症的发生，但机制尚不完全清楚。申请人前期证实复制起始因子WDHD1参与宫颈癌细胞G1检验点的调控。前期结果RNA-seq发现WDHD1潜在的调控蛋白STAT3及下游分子GCN5表达上调；敲低WDHD1下调GCN5的表达并使E7细胞停滞在G1检验点；ChIP显示STAT3可与WDHD1的启动子区结合。据此提出科学假说：WDHD1通过调节GCN5，介导E7细胞逃避G1检验点，而WDHD1的表达可能受STAT3调控。本项目将阐明WDHD1帮助E7细胞逃避G1检验点的机制，明确STAT3调控WDHD1的机理，从而揭示HPV诱导基因组不稳定的新机制，以期找到药物治疗新靶点。

背景：人乳头瘤病毒（HPV）感染是宫颈癌发生的主要诱因。预防性疫苗对已感染或免疫抑制病人无效，且临床尚无特异性药物，因此深入探讨高危型HPV的致癌机制仍具有重要的临床意义。HPV早期基因E7可使G1检验点失活，进而诱导基因组不稳定及癌症的发生，但机制尚不完全清楚。我们最近的研究表明复制起始因子WDHD1可以参与调节宫颈癌细胞的G1检查点, 本研究旨在探讨WDHD1直接参与HPV细胞G1检查点调控的机制。此外，信号转导和转录激活因子3（STAT3）在细胞生长和癌症发生过程中起着关键作用。然而，STAT3调节细胞生长和癌症发生的功能和机制尚未完全了解。.结果：由于目前尚无关于WDHD1对乳头瘤病毒G1检查点的调节和机制的报道，我们的数据首先证实了一种新的WDHD1/GCN5/Akt通路，该通路独立于DNA复制起始，导致在DNA受损的情况下G1检查点被取消，并诱导肿瘤的发生。此外，本研究还探索了STAT3 DNA复制的一个新功能，且发现WDHD1是一种新的STAT3靶基因，STAT3通过与WDHD1启动子区域结合，介导后者的转录。.科学意义: 本项目阐明了WDHD1帮助E7细胞逃避G1检验点的机制，明确了STAT3调控WDHD1的机理，揭示了HPV诱导基因组不稳定的新机制。