Mechanisms of KSHV-induced endothelial cell loss of contact inhibition of proliferation

总结 卡波西肉瘤相关疱疹病毒（KSHV）导致艾滋病定义癌症卡波西肉瘤（KS）。 KSHV感染的KS肿瘤细胞（KSC）表达增殖标记物，表明接触抑制的丧失 增殖（CIP）。CIP被认为是一种肿瘤抑制途径，CIP的丢失是肿瘤的一个重要特征。 实体瘤中的致癌转化。KSHV如何拮抗CIP尚不清楚。KS肿瘤细胞大多数 可能起源于微血管淋巴管内皮细胞（LEC）。因此，LECs代表了 原代人LEC从头感染后KS、KSHV诱导增殖研究的相关模型 还没有被证明。我们已经开发了KSHV感染原代人LEC的方案， 可以让我们测量KSHV引起的CIP损失。这一应用的核心假设是， KSHV诱导的CIP丢失是KS肿瘤发生的关键驱动特征。我们的初步工作表明， KSHV miR-K10 miRNAs对KSHV诱导的LEC中CIP丢失有重要作用，但不是KSHV诱导的LEC中CIP丢失的主要原因。 只有这种表型的病毒决定簇。我们的结果进一步暗示了病毒对p27的抑制， 粘附连接（AJs），以及KSHV介导的细胞骨架和囊泡运输的失调。 失去CIP。为了验证我们的假设，并阐明KSHV诱导的CIP丢失的机制，我们 提出三个具体目标。在具体目标1中，我们将确定四种miR-K10 miRNAs的表达， 在KSHV感染的LEC和KS中。我们还将定义他们各自对KSHV引起的损失的贡献， 总督察在具体目标2中，我们将确定KSHV中miR-K10诱导的CIP丢失的潜在机制。 感染的淋巴细胞在具体目标3中，我们将鉴定促进KSHV诱导的CIP丧失的其他病毒基因。 拟议的研究是创新的，因为我们的模型提供了严格定义的实验设置， 能够分析KSHV感染原代人细胞类型后诱导的CIP损失， KS.这项工作是重要的，因为它将建立KSHV诱导LEC增殖的病毒决定因素， 从而解释KS的致癌机制。结果将是有影响的，因为CIP是一种肿瘤抑制剂。 机制了解KSHV如何克服CIP将有助于我们解释KSHV如何导致KS， 可能被用于KS的治疗干预。

SUMMARY Kaposi’s Sarcoma-associated herpesvirus (KSHV) causes the AIDS-defining cancer Kaposi’s Sarcoma (KS). The KSHV-infected KS tumor cells (KSCs) express proliferation markers, indicating a loss of contact inhibition of proliferation (CIP). CIP is considered a tumor suppressive pathway, and loss of CIP is a crucial feature of oncogenic transformation in solid tumors. How KSHV antagonizes CIP is not known. The KS tumor cells most likely originate from microvascular lymphatic endothelial cells (LECs). While LECs therefore represent a relevant model for studies of KS, KSHV-induced proliferation after de novo infection of primary human LECs has not been demonstrated. We have developed a protocol for KSHV infection of primary human LECs that allows us to measure KSHV-induced loss of CIP. The central hypothesis underlying this application is that KSHV-induced loss of CIP is a critical driving feature of oncogenesis in KS. Our preliminary work shows that the KSHV miR-K10 miRNAs contribute substantially to the KSHV-induced loss of CIP in LECs but are not the only viral determinants of this phenotype. Our results furthermore implicate viral repression of p27, disruption of adherens junctions (AJs), and deregulation of the cytoskeleton and vesicular trafficking in KSHV-mediated loss of CIP. To test our hypothesis and elucidate the mechanisms underlying KSHV-induced loss of CIP, we propose three Specific Aims. In Specific Aim 1, we will determine the expression of the four miR-K10 miRNAs in KSHV-infected LECs and KS. We will also define their individual contributions to the KSHV-induced loss of CIP. In Specific Aim 2, we will identify the mechanisms underlying the miR-K10-induced loss of CIP in KSHV- infected LECs. In Specific Aim 3, we will identify other viral genes that promote the KSHV-induced loss of CIP. The proposed study is innovative because our model provides rigorously defined experimental settings that enable the analysis of KSHV-induced loss of CIP after infection of a primary human cell type with relevance to KS. This work is significant because it will establish the viral determinants of KSHV-induced LEC proliferation, thereby explaining oncogenic mechanisms in KS. Results will be impactful since CIP is a tumor-suppressive mechanism. Understanding how KSHV overcomes CIP will help us to explain how KSHV causes KS and could potentially be exploited for therapeutic intervention in KS.