Targeting MCPyV oncogene transcription to suppress tumorigenesis

项目摘要 默克尔细胞多瘤病毒（MCPyV）是一种普遍存在的皮肤感染，可导致默克尔细胞癌 (MCC)是一种高度侵袭性的皮肤癌。免疫抑制是最重要的风险之一 与MCPyV相关的MCC的发展因素。MCPyV有更大的机会诱发癌症 免疫功能低下的个体，包括艾滋病毒感染者的发展。但无论 MCPyV生命周期和致癌机制仍然知之甚少。MCC的发病率 在过去的20年里增加了两倍，但缺乏有效的治疗方法。因此，更好的 需要了解MCPyV的生命周期和致癌机制， 有效的治疗。在MCPyV感染的细胞中，早期启动子（EP）支持MCPyV的转录。 早期基因，并在维持持续感染中发挥关键作用。在大多数MCC中， MCPyV DNA克隆整合到癌症基因组中，其中EP驱动MCPyV基因的表达。 病毒癌基因，大和小T抗原，以促进MCC肿瘤生长。MCPyV EP转录 因此对于支持MCC肿瘤发生也是至关重要的。然而，人们对它知之甚少。 在MCPyV感染或MCC发展期间调节MCPyV EP的机制。这一差距 在我们的知识中，主要是因为直到最近，MCPyV的细胞向性是未知的， 缺乏用于研究MCPyV的生物学相关的培养系统。我们最近发现 人皮肤成纤维细胞（HDF）作为MCPyV感染的天然宿主细胞。我们发现MCPyV 进入是一个混杂的过程，而其转录是MCPyV宿主细胞的关键决定因素 嗜性、持续感染和致癌潜力。建立在体外和离体感染的基础上 在我们最近的研究中开发的模型，我们建议发现表观遗传机制（目的1） 以及调节MCPyV早期的宿主细胞因子和顺式作用病毒DNA元件（Aim 2 基因转录我们还将应用最近开发的脂质纳米颗粒（LNP）技术， 阻断MCPyV癌基因转录和消除MCC肿瘤发生（Aim 3）。我们的研究将填补 在了解早期调节MCPyV的机制方面存在重大知识差距 转录过程中的病毒生命周期和MCC致瘤发展。此外，我们的调查 将为这种新的人类肿瘤的病毒学和致癌机制提供重要的见解 病毒，并确定新的目标，以制定更好的战略，以治疗高致命性MCC皮肤 发病率迅速上升的癌症。正如COVID-19疫苗的成功所证明的那样， 高效LNP在治疗应用中显示出巨大的前景。因此， LNP的体内递送能力为将我们的发现转化为临床环境提供了可行的平台。

Project Summary Merkel cell polyomavirus (MCPyV) is a ubiquitous skin infection that can cause Merkel cell carcinoma (MCC), a highly aggressive form of skin cancer. Immune suppression is one of the most important risk factors for developing MCPyV-associated MCC. MCPyV has a far greater chance to induce cancer development among immunocompromised individuals, including HIV-infected patients. However, both the MCPyV life cycle and oncogenic mechanisms remain poorly understood. The incidence of MCC has tripled over the past twenty years, but effective treatments are lacking. Therefore, a better understanding of the MCPyV life cycle and oncogenic mechanisms is needed for developing more effective treatments. In MCPyV-infected cells, the early promoter (EP) supports the transcription of early genes and plays a critical role in maintaining persistent infection. In the majority of MCCs, MCPyV DNA is clonally integrated into the cancer genome, where the EP drives the expression of viral oncogenes, large and small T antigens, to promote MCC tumor growth. MCPyV EP transcription therefore is also critical for supporting MCC oncogenesis. However, very little is known about the mechanisms that regulate MCPyV EP during either MCPyV infection or MCC development. This gap in our knowledge is largely because, until recently, the cellular tropism of MCPyV was unknown and there was a lack of a biologically relevant culture system for studying MCPyV. We recently identified human dermal fibroblast (HDF) as a natural host cell for MCPyV infection. We found that MCPyV entry is a promiscuous process, whereas its transcription is the key determinant for MCPyV host cell tropism, persistent infection, and oncogenic potential. Building on the in vitro and ex vivo infection models developed in our recent studies, we propose to discover the epigenetic mechanisms (Aim 1) as well as host cellular factors and cis-acting viral DNA elements (Aim 2) that regulate MCPyV early gene transcription. We will also apply the recently developed lipid nanoparticle (LNP) technology to abolish MCPyV oncogene transcription and obliterate MCC tumorigenesis (Aim 3). Our studies will fill a significant knowledge gap in understanding the mechanisms that regulate MCPyV early transcription during the viral life cycle and MCC tumorigenic development. Moreover, our investigation will provide important insights into the virology and oncogenic mechanism of this new human tumor virus, and identify novel targets for developing better strategies to treat the highly lethal MCC skin cancers with a rapidly rising incidence. As demonstrated by the success of COVID-19 vaccines, the highly potent LNPs have shown great promise for therapeutic applications. Therefore, the superb in vivo delivery power of LNPs affords a viable platform for translating our findings into clinical setting.