Development of Oncolytic Reovirus for Triple-Negative Breast Cancer

本提案的目的是确定促进呼肠孤病毒感染和TNBC细胞杀伤的病毒和宿主因子，并确定可以增强病毒介导的癌细胞杀伤的小分子抑制剂。在美国，乳腺癌是癌症的主要原因，也是女性癌症相关死亡的主要原因。哺乳动物正呼肠孤病毒（呼肠孤病毒）是一种分节的、无包膜的dsRNA病毒，主要感染转化细胞，目前正处于I-III期临床试验中，以评估其作为病毒溶瘤剂治疗几种癌症的疗效。初步数据表明，血清1型呼肠孤病毒比血清3型呼肠孤病毒更有效地诱导TNBC细胞死亡，并且细胞死亡是通过不依赖于caspase 3的途径发生的。RNA测序显示IL-24在呼肠孤病毒感染TNBC细胞期间高度上调，高通量筛选鉴定了拓扑异构酶抑制剂（阿霉素、表阿霉素、依泊泊苷和拓扑替康），当与呼肠孤病毒配对时，可促进有效的TNBC细胞死亡。中心假设是，在拓扑异构酶抑制剂存在的情况下，呼肠孤病毒感染血清型1呼肠孤病毒诱导互补信号通路，导致TNBC细胞死亡。提出了两个综合的具体目标。特异性目的1将阐明呼肠孤病毒诱导三阴性乳腺癌细胞死亡的机制。特异性目标2将确定拓扑异构酶抑制剂如何影响呼肠孤病毒感染。这些实验将增强对病毒杀死癌细胞的机制的理解，确定组合病毒和小分子抑制剂方案如何影响病毒感染，并为TNBC患者提供个性化治疗选择的信息。

The objective of this proposal is to identify viral and host factors that promote reovirus infection and cell killing of TNBC cells and identify small molecule inhibitors that can augment viral-mediated killing of cancer cells. In the U.S., breast cancer is the leading cause of cancer and a leading cause of cancer-related deaths in women. Mammalian orthoreovirus (reovirus) is a segmented, nonenveloped dsRNA virus that predominantly infects transformed cells and is in Phase I-III clinical trials to assess its efficacy as a viral oncolytic against several cancers. Preliminary data indicate that serotype 1 reoviruses induce more efficient TNBC cell death than serotype 3 reoviruses and that cell death occurs via a caspase 3-independent pathway. RNA sequencing showed that IL-24 is highly upregulated during reovirus infection of TNBC cells and high-throughput screening identified topoisomerase inhibitors (doxorubicin, epirubicin, etoposide, and topotecan) that when paired with reovirus promote efficacious TNBC cell death. The central hypothesis is that reovirus infection with serotype 1 reoviruses in the presence of topoisomerase inhibitors induces complementary signaling pathways that result in TNBC cell death. Two integrated specific aims are proposed. Specific Aim 1 will elucidate mechanisms of reovirus-induced cell death of triple-negative breast cancer cells. Specific Aim 2 will determine how topoisomerase inhibitors impact reovirus infection. These experiments will enhance an understanding of the mechanism viruses use to kill cancer cells, define how combinatorial virus and small molecule inhibitor regimens impact viral infection, and inform the development of personalized therapeutic options for patients afflicted with TNBC.