Targeting vFLIP for the treatment of KSHV-associated malignancies

描述（由申请人提供）：卡波西肉瘤（KS）是hiv感染者中最常见的癌症，也是非洲南部几个国家最常见的恶性肿瘤。目前的治疗方案在很大程度上是无法治愈的，虽然KS是由卡波西氏肉瘤疱疹病毒（KSHV）引起的，但没有有效的病毒特异性治疗方法。KSHV还引起原发性积液性淋巴瘤（PEL）和多中心Castleman病（MCD），这两种疾病也是致命和无法治愈的疾病。我们的首要目标是开发新的靶向治疗kshv相关疾病。实验证据表明，kshv编码的蛋白vFLIP是一个潜在的治疗靶点。vFLIP在PEL细胞中负责NF-kB活性，这些细胞中vFLIP的消除导致肿瘤细胞凋亡和自噬。在B细胞中转基因表达vFLIP可诱导小鼠B细胞源性肿瘤。这些观察结果支持vFLIP作为一种病毒致癌基因的作用，并表明PEL细胞对这种病毒蛋白存在“依赖性”，支持抑制vFLIP是治疗PEL的可行治疗方法的观点。也有大量证据表明vFLIP在卡波西肉瘤的发病机制中发挥作用，因为它在病变细胞中表达，在内皮细胞中表达时具有多种转化作用。通过改进筛选方法、充分的动物模型和对vFLIP介导的肿瘤发生的更深入了解，将有助于鉴定KSHV vFLIP抑制剂。通过鉴定vFLIP的小分子抑制剂，以及开发具有强大肿瘤表型的vFLIP条件敲入小鼠，我们已经朝着这些目标取得了进展。我们建议通过以下具体目标进行更多的临床前研究来开发和测试vFLIP抑制剂：1)表征已鉴定的vFLIP小分子抑制剂，进行结构-活性关系分析，并确定改进的下一代vFLIP抑制剂；2)评估其他vFLIP相互作用，并评估其与vFLIP功能和病毒发病机制的相关性；3)在KSHV vFLIP恶性肿瘤动物模型中检测最有希望的vFLIP抑制剂。通过这些目标，我们期望确定强大的vFLIP抑制剂，并获得临床前必要的信息，以进行后续开发，以进行最佳候选药物的临床测试。此外，我们希望进一步了解vFLIP的结构和功能，开发改进的动物模型，从而提高我们对kshv相关恶性肿瘤病理生物学的理解。

DESCRIPTION (provided by applicant): Kaposi's sarcoma (KS) is the most frequent cancer in HIV-infected individuals and the most common malignancy in several countries in subequatorial Africa. KS is largely incurable with current therapeutic options, and while KS is caused by the Kaposi's sarcoma herpesvirus (KSHV), no effective virus-specific therapies exist. KSHV also causes primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD), which are also lethal and incurable diseases. Our overarching goal is to develop novel targeted therapies for KSHV-associate diseases. Experimental evidence indicates that the KSHV-encoded protein vFLIP is a potential therapeutic target. vFLIP is responsible for NF-kB activity in PEL cells, and elimination of vFLIP in these cells results in tumor cell apoptosis and autophagy. Transgenic expression of vFLIP in B cells induces tumors of B cell origin in mice. These observations support the role of vFLIP as a viral oncogene, and indicate that there is "addiction" to this viral protein in PEL cells, supporting the notion that inhibition of vFLIP is a viable therapeutic approach for the treatment of PEL. There is also substantial evidence that vFLIP plays a role in the pathogenesis of Kaposi's sarcoma, as it is expressed in lesional cells and has a variety of transforming effects when expressed in endothelial cells. Identification of inhibitors of KSHV vFLIP will be facilitated by the development of improved screening methodologies, adequate animal models and a deeper understanding of vFLIP-mediated oncogenesis. We have made progress towards these goals by identifying small molecule inhibitors of vFLIP, and developing vFLIP conditional knock-in mice with a robust tumor phenotype. We propose to perform additional preclinical studies to develop and test vFLIP inhibitors through the following specific aims: 1) characterize small molecule inhibitors of vFLIP already identified, perform structure-activity relationship analysis, and identify improved next generation inhibitors of vFLIP; 2) evaluate other vFLIP interactions and assess their relevance to vFLIP function and viral pathogenesis; and 3) test the most promising inhibitors of vFLIP in animal models of KSHV vFLIP malignancy. Through these aims we expect to identify robust vFLIP inhibitors and acquire the preclinical information necessary to pursue subsequent development for clinical testing of the best candidate. In addition, we expect to gain further insights on vFLIP structure and function, develop improved animal models, thereby advancing our understanding of the pathobiology of KSHV-associated malignancies.