Oncolytic activity of respiratory syncytial virus against prostate cancer

描述（由申请人提供）：前列腺癌是一种恶性肿瘤，其侵袭性形式会扩散到骨骼和身体的许多其他部位。老年男性人口特别容易患这种疾病，因为从生命的第五个十年开始，前列腺癌的风险稳步上升。事实上，在70岁以上的男性中，约60%的新发实体瘤是前列腺肿瘤。转移性前列腺癌是老年男性癌症死亡的主要原因。该研究有望为基于溶瘤性人呼吸道合胞病毒（RSV）选择性杀伤前列腺肿瘤细胞的前列腺癌治疗策略提供新的信息。溶瘤病毒疗法是一种新兴的癌症生物治疗平台，其基础是选择性感染和“杀死”癌细胞。迄今为止，已鉴定出八种溶瘤病毒。然而，最近的临床试验表明，需要一种多病毒的病毒治疗方法来治疗侵袭性癌症，因此，迫切需要识别新的溶瘤病毒。为此，我们确定RSV是一种新的溶瘤病毒，因为RSV对前列腺肿瘤细胞具有强大的抗癌活性。我们的研究结果表明，与非致瘤性的RWPE-1人前列腺细胞相比，RSV在雄激素不敏感、高度转移的PC-3人前列腺癌细胞中的传染性显著增强。在裸鼠培养的人前列腺肿瘤异种移植物中，PC-3细胞的病毒负荷增强导致PC-3癌细胞在体外和体内选择性“杀死”。我们进一步证明RSV溶瘤功能的可能机制涉及NF-？PC-3细胞B依赖性先天抗病毒反应。由于抗病毒先天免疫构成了限制病毒感染的第一道防线，我们推测PC-3细胞的先天反应功能失调是病毒感染性和溶瘤性增加的原因。本研究将有两个具体目的：目的1)在肿瘤异种移植物和前列腺癌TRAMP小鼠模型中表征rsv介导的前列腺癌细胞的体内溶瘤。目的2)研究解除管制的NF-？B依赖的抗病毒途径赋予RSV在前列腺癌细胞中的溶瘤功能。rsv介导的体内肿瘤溶解将根据肿瘤消退进行评估；前列腺癌组织学;原位细胞凋亡；和PC-3细胞在荧光原位模型中的转移扩散。管制NF - ?B的功能将通过细胞生物学方法进行探索，包括敲除特定的NF-？B家族成员通过慢病毒介导siRNA表达和染色质免疫沉淀。意义：RSV的溶瘤特性可作为特异性靶向前列腺肿瘤的有效治疗工具。公共卫生相关性：前列腺癌是老年人死亡的主要原因，需要新的抗癌治疗来控制这种疾病。我们已经确定呼吸道合胞病毒作为一种新的抗癌剂，可以选择性地破坏前列腺癌细胞，但不是正常细胞。因此，该病毒可作为一种治疗手段，用于设计安全有效的靶向前列腺肿瘤的基于病毒的抗癌药物。

DESCRIPTION (provided by applicant): Prostate cancer is a malignant tumor, which in its aggressive form would spread to the bone and many other parts of the body. The aging male population is especially susceptible to this disease, since from the 5th decade of life the prostate cancer risk rises steadily. In fact, ~ 60% new cases of solid tumors in men over age 70 represent tumors in the prostate gland. Metastatic prostate cancer is the leading cause of cancer deaths among elderly men. The proposed study is expected to provide novel information on the strategy to manage prostate cancer based on selective killing of prostate tumor cells by the oncolytic human respiratory syncytial virus (RSV). Oncolytic virotherapy is an emerging bio-therapeutic platform for cancer treatment, which is based on selective infection and "killing" of cancer cells. To date, eight oncolytic viruses have been identified. However, recent clinical trials indicated the need for a multi-virus virotherapy approach for the treatment of aggressive cancers and thus, the urgency to identify novel oncolytic viruses. To this end, we have identified RSV as a novel oncolytic virus, since RSV possesses potent anti-cancer activity against prostate tumor cells. Our results demonstrated dramatic enhancement of RSV infectivity in the androgen-insensitive, highly metastatic PC-3 human prostate cancer cells compared to the non-tumorigenic RWPE-1 human prostate cells. The enhanced viral burden in PC-3 cells leads to selective "killing" of PC-3 cancer cells in vitro and in vivo in human prostate tumor xenografts grown in nude mice. We further demonstrated that the possible mechanism underlying the oncolytic function of RSV involves defect in the NF-?B dependent innate anti-viral response in PC-3 cells. Since anti-viral innate immunity constitutes the first line of defense directed to restrict viral infection, we speculate that dysfunctional innate response in PC-3 cells is responsible for the increased viral infectivity and oncolysis. The proposed study will be pursued with two Specific Aims: Aim 1) Characterize the RSV-mediated oncolysis of prostate cancer cells in vivo in tumor xenografts and in the TRAMP mouse model of prostate cancer. Aim 2) Study the role of the deregulated NF-?B dependent anti-viral pathway in conferring the oncolytic function to RSV in prostate cancer cells. RSV-mediated oncolysis in vivo will be assessed based on tumor regression; prostate histology; apoptosis in situ; and metastatic spread of PC-3 cells in a fluorescent orthotopic model. Deregulated NF-?B function will be explored using cell biology approaches including knock down of specific NF-?B family members by lentivirus-mediated siRNA expression and chromatin immunoprecipitation. Significance: The oncolytic property of RSV could be developed as an efficient therapeutic tool to specifically target prostate tumors. PUBLIC HEALTH RELEVANCE: Prostate cancer is a leading cause of mortality among elderly population and novel anti-cancer treatment is necessary to control this disease. We have identified respiratory syncytial virus as a novel anti-cancer agent that could selectively destroy prostate cancer cells, but not normal cells. Therefore, this virus could be utilized as a therapeutic to design safe and efficient virus-based anti-cancer agents to specifically target prostate tumors.