T Cell Based Carriers for In Vivo Gene Therapy of Cancer

描述（由申请人提供）：癌症基因治疗的成功最终将取决于在体内将基因特异性地递送到肿瘤细胞。然而，由于低滴度、免疫失活、非特异性粘附和循环中病毒颗粒的损失，系统给药病毒库存迄今尚未实现转移性疾病的治疗靶向。因此，如果载体能够被携带到肿瘤生长的局部部位，并根据外部施加的信号（如药物）或肿瘤本身的生物学特性提供的环境线索而释放出来，这将是有价值的。几种类型的细胞可以作为肿瘤归巢细胞载体，包括肿瘤抗原特异性T细胞。我们最近的研究表明，在转移性疾病模型中，系统递送表面靶向T细胞，在T细胞识别特定肿瘤抗原后产生转录肿瘤靶向逆转录病毒载体，产生了非常显著的治疗效果。然而，我们的T细胞研究使用了缺乏细胞溶解效应功能的人类T细胞，在缺乏功能性免疫系统的小鼠中。我们现在建议将T细胞载体的概念扩展到癌症的基因治疗中。如图18和19所示，我们将：1：证明抗原特异性的小鼠细胞毒性T细胞可以在体外转化为逆转录病毒产生细胞，它们可以在体内过继性地转移到携带肿瘤的宿主，并且它们可以在完全完整的免疫系统存在的情况下运输并特异性转导抗原阳性肿瘤；在免疫能力强的恶性黑色素瘤小鼠模型中，在过继性T细胞治疗方案中，通过将肿瘤局部产生的细胞毒性逆转录病毒与T细胞的自然效应功能（靶细胞杀伤和细胞因子释放）相结合，确定治疗增强的特征；研究基于抗原特异性T细胞的逆转录病毒载体在肿瘤部位产生的潜力，以增强进一步剂量的过继转移T细胞的募集和内源性抗肿瘤免疫效应物的募集/激活。在临床上，这些实验将迅速导致改善癌症过继性T细胞治疗的患者试验，它们将开发基于细胞的载体的潜力，用于转移性疾病的体内基因传递。

DESCRIPTION (provided by applicant): The success of gene therapy for cancer will eventually depend on delivering genes specifically to tumor cells in vivo. However, systemic administration of viral stocks has not so far achieved therapeutic targeting of metastatic disease, due to low titres, immune inactivation, non-specific adhesion and loss of viral paticles in the circulation. It would, therefore, be valuable if vectors could be carried to local sites of tumor growth and be released in response to externally applied signals (such as drugs) or environmental cues supplied by the biological properties of the tumor itself. Several cell types could serve as tumor homing cell carriers of vectors, including tumor antigen specific T cells. We have recently shown that systemic delivery of surface targeted T cells, engineered to produce a transcriptionally tumor targeted retroviral vector upon recognition by the T cell of a specific tumor antigen, generated highly significant therapeutic effects in a model of metastatic disease. However, our T cell studies used human T cells lacking cytolytic effector functions, in mice lacking a functional immune system. We now propose to expand the concept of T cell carriers for the gene therapy of cancer. As summarized in Figures 18 and 19 we will 1: Demonstrate that antigen specific, murine cytotoxic T cells can be converted into retroviral producer cells in vitro, that they can be adoptively transferred in vivo to tumor bearing hosts and that they can traffick to and specifically transduce antigen positive tumors in the presence of a fully intact immune system: 2: Characterise the therapeutic enhancement produced by combining tumor localized production of cytotoxic retrovirus with the T cells' natural effector functions (target cell killing and cytokine release) in a protocol of adoptive T cell therapy in an immunocompetent murine model of malignant melanoma: and 3; Investigate the potential of antigen specific T cell based retroviral vector production at the tumor site to enhance the recruitment of further doses of adoptively transferred T cells and the recruitment/activation of endogenous anti tumor immune effectors. Clinically, these experiments should rapidly lead to improved patient trials for adoptive T cell therapy of cancer and they will develop the potential of cell-based carriers for in vivo gene delivery to metastatic disease.