MODULATION OF HOST CELL APOPTOTIC RESPONSES BY HPVE7

描述(申请人提供)：高危人乳头瘤病毒(HPV)是宫颈癌的病原体，是全球女性癌症死亡的第二大常见原因。此外，高危HPV还与其他一些肛门生殖道癌有关，包括肛门癌、外阴癌和阴道癌，以及大约20%的口腔癌。尽管最近推出了一种预防性疫苗，以防止感染一些高危HPV类型，但这将在几十年后才能影响宫颈癌的发病率和死亡率。目前，仅在美国，每天就有10名女性死于宫颈癌。HPV相关的癌变是由HPVE6/E7癌蛋白的表达驱动的；这些蛋白不仅有助于诱发癌前病变，而且还从机械上促进恶性进展，这是一种相对罕见的事件，通常发生在首次感染后几年到几十年。进展通常与HPV基因组整合到宿主细胞染色体有关，这是病毒生命周期的终端事件。因此，E6和E7是仅有的在宫颈癌中持续表达的病毒蛋白。该项目的重点是研究高危HPV癌蛋白的生物活性，并确定它们是否可以被用作治疗高危HPV相关病变和癌症的一种新的治疗方式。在目标1中，我们建议确定HPV16E7在人角质形成细胞中诱导营养前哨信号的机制基础，这是一种细胞肿瘤抑制途径，可以阻止遭受癌基因改变的细胞的增殖，从而导致细胞异常增殖。目的2是确定HPV16E7诱导角质形成细胞自噬的机制基础，以及这种自噬是否/如何与营养前哨信号有关。由于自噬是对代谢压力的一种古老而保守的进化反应，我们将确定HPV16E7的表达是如何导致代谢需求增加的。目的3探讨HPV16E6阻断HPV16E7诱导的营养前哨信号的机制。在这个目标中，我们将测试E6和E7可能靶向的通路的小分子抑制剂是否可以作为治疗HPV相关病变和癌症的一种新的治疗方式。由于E6和E7癌蛋白靶向的细胞通路经常因非HPV相关的人类实体肿瘤的突变而功能障碍，这些研究也可能适用于其他人类癌症的治疗。 公共卫生相关性：感染高危人乳头瘤病毒(HPV)与多种人类癌症有关，包括宫颈癌，这是全球女性癌症死亡的第二大常见原因。尽管最近推出了预防性HPV疫苗，但这种疫苗接种将在几十年后降低宫颈癌的发病率和死亡率，在接下来的几十年里，美国每天都有超过10名女性死于HPV相关的宫颈癌。这项建议的重点是确定HPV16 E7癌蛋白表达导致细胞自杀的分子机制，描述E6癌蛋白抑制E7活性的机制，并对临床上已有的小分子抑制剂进行原理实验证明，以确定这种休眠的细胞死亡反应是否可被利用作为HPV相关病变和癌症的治疗方式。

DESCRIPTION (provided by applicant): High-risk human papillomaviruses (HPVs) are etiological agents of cervical cancer, the second most common cause of cancer death in women worldwide. In addition, high-risk HPVs are also associated with a number of other anogenital tract carcinomas, including, anal, vulvar and penile cancers as well as approximately 20% of oral cancers. Despite the recent introduction of a prophylactic vaccine that is to protect from infection with some high-risk HPV types, it will be several decades before this will affect cervical cancer incidence and death rates. Currently 10 women succumb to cervical cancer every day in the US, alone. HPV-associated carcinogenesis is driven by HPV E6/E7 oncoprotein expression; these proteins not only contribute to induction of premalignant lesions, but also mechanistically contribute to malignant progression, a relatively rare event that generally occurs several years to decades after the initial infection. Progression is frequently associated with HPV genome integration into a host cellular chromosome, a terminal event for the viral life cycle. As a consequence, E6 and E7 are the only viral proteins that are consistently expressed in cervical cancers. This project is focused on investigating biological activities of high-risk HPV oncoproteins and to determine whether they could be harnessed as a novel therapeutic modality for high-risk HPV-associated lesions and cancers. In aim 1, it is proposed to determine the mechanistic basis of HPV16 E7-induced trophic sentinel signaling in human keratinocytes, a cellular tumor suppressor pathway that thwarts the proliferation of cells that have suffered oncogenic alterations, which lead to aberrant cell proliferation. Aim 2 is to determine the mechanistic basis of HPV16 E7-induced autophagy in human keratinocytes and if/how this is connected to trophic sentinel signaling. Since autophagy is an evolutionary ancient and conserved response to metabolic stress we will determine how HPV16 E7 expression causes increased metabolic requirements. Aim 3 is to investigate the mechanism by which HPV16 E6 abrogates HPV16 E7 induced trophic sentinel signaling. In this aim we will test whether small molecule inhibitors of the pathways that E6 and E7 may be targeting and that are currently in the clinic may be harnessed as a novel therapeutic modality for HPV-associated lesions and cancers. Since the cellular pathways that are targeted by the E6 and E7 oncoproteins are frequently rendered dysfunctional by mutation in non-HPV associated human solid tumors, these studies may also be applicable for therapy of other human cancers. PUBLIC HEALTH RELEVANCE: Infections with high-risk human papillomaviruses (HPVs) have been associated with variety human cancers, including cervical carcinoma, the second most common cause of cancer death in women worldwide. Despite the recent introduction of a prophylactic HPV vaccine, it will be decades before such vaccination will decrease incidence and mortality of cervical cancer and more than 10 women will succumb to HPV-associated cervical cancer in the US every day for the next several decades. The focus of this proposal is to determine the molecular mechanisms by which HPV16 E7 oncoprotein expression predisposes cells to commit cellular suicide, to delineate the mechanism by which the E6 oncoprotein holds this E7 activity in check and to perform proof of principle experiments with small molecule inhibitors that are already in the clinic to determine whether this dormant cell death response may be harnessed as a therapeutic modality for HPV-associated lesions and cancers.