Combinatorial targeting of melanoma initiating cells

描述(申请人提供)：本提案的目标是测试一种新的概念，即针对恶性黑色素瘤起始细胞(MMIC)和肿瘤相关周细胞的组合免疫疗法与持续低剂量环磷酰胺(即节律化疗)相结合，代表了有效治疗恶性黑色素瘤的新概念。这一策略源于下列证据：i)癌症干细胞(CSC)必须以肿瘤干细胞(CSC)为靶点，才能成为有效的抗癌治疗方法，因为CSC理论假设肿瘤中只有一小部分细胞具有自我更新、致癌、耐药和放射耐药的能力；ii)由于恶性黑色素瘤的发病率持续上升，且目前尚无有效的治疗方法，因此迫切需要开发一种有效的治疗方法；iii)T细胞和抗体为基础的免疫治疗的组合，针对肿瘤微环境中的MMIC和肿瘤相关周细胞，有望抵消肿瘤细胞为避免免疫识别而利用的多种逃逸机制。我们的策略选择的靶点是硫酸软骨素蛋白多糖4(CSPG4)，它将成为T和抗体免疫治疗的靶点。利用生存手术-复发-转移模型，本方案的具体目的是验证这样的假设，即T细胞和抗体为基础的联合免疫疗法结合节律化疗有效地抑制了从细胞系和皮损中分离的人MMIC在手术切除原发肿瘤后在免疫缺陷小鼠中的复发和转移扩散。这些概述的研究将受益于多个相关研究领域的现有专业知识和独特试剂的可获得性，预计将对CSC和恶性黑色素瘤的免疫治疗领域做出新的和潜在的重要贡献。

DESCRIPTION (provided by applicant): The goal of this proposal is to test the novel concept that an effective treatment for malignant melanoma is represented by a combinatorial immunotherapy, which targets malignant melanoma initiating cells (MMIC) and tumor-associated pericytes, in combination with continuous low dose cyclophosphamide, i.e. metronomic chemotherapy. This strategy stems from the following lines of evidence: i) cancer stem cells (CSC) have to be targeted for a therapy to be an effective anticancer treatment, since the CSC theory postulates that only a small cell population in tumors is self-renewing, tumorigenic and drug- and radio-resistant, ii) there is an urgent need to develop an effective therapy of malignant melanoma, since its incidence continues to increase and no effective therapy is available, and iii) a combination of T cell- and antibody-based immunotherapy that targets MMIC and tumor-associated pericytes in the tumor microenvironment is expected to counteract the multiple escape mechanisms utilized by tumor cells to avoid immune recognition. The target selected for our strategy is chondroitin sulfate proteoglycan 4 (CSPG4) which will be targeted with T- and antibody-based immunotherapy. Utilizing a survival surgery- recurrence-metastasis model, the specific aims of this proposal are to test the hypothesis that combinatorial T cell- and antibody- based immunotherapy in combination with metronomic chemotherapy is effective in inhibiting recurrence and metastatic spreading in immunodeficient mice of human MMIC isolated from cell lines and from lesions, following surgical removal of the grafted primary tumor. The outlined studies, which will benefit from the available expertise in multiple relevant research areas and the availability of unique reagents, are expected to yield novel and potentially important contributions to the fields of CSC and immunotherapy of malignant melanoma.