Experimental Uveal Melanoma and Ocular Immune Privilege

描述：葡萄膜黑色素瘤是成人最常见的原发性恶性眼内肿瘤。肝脏转移性疾病是葡萄膜黑色素瘤患者死亡的主要原因，目前尚无有效的治疗方法。由于缺乏令人满意的动物模型，葡萄膜黑色素细胞原位转化并转移到肝脏，葡萄膜黑色素瘤的治疗方法的开发和测试一直受到阻碍。此外，很少有眼部来源的小鼠黑色素瘤细胞系可用于研究葡萄膜黑色素瘤的免疫逃避和肝转移机制。本提案的目的是开发SV40 t抗原（Tag）转基因，其元件允许酪氨酸酶启动子在cre -重组酶存在下诱导SV40 Tag的表达。这种转基因将允许C57BI/6小鼠的色素组织（包括黑素细胞）的诱导原位转化，通过靶向药物输送到眼睛的前部或后部，以诱导cre -重组酶的活性。这些小鼠将通过监测SV40标签特异性来表征对原发性和转移性葡萄膜黑色素瘤的免疫反应

DESCRIPTION: Uveal melanoma is the most common primary malignant intraocular tumor in adults. Metastatic disease of the liver is the leading cause of death in uveal melanoma patients and there is currently no effective treatment. Developing and testing therapies for uveal melanoma has been hampered by the absence of a satisfactory animal model in which uveal melanocytes are transformed in situ and metastasize to the liver. In addition, few murine melanoma cell lines of ocular origin are available for studies aimed at understanding the mechanisms of immune evasion and liver metastasis by uveal melanoma. The objective of this proposal is to develop an SV40 T-antigen (Tag) transgene with elements that allow inducible expression of SV40 Tag by the tyrosinase promoter in the presence of Cre-recombinase. This transgene will permit inducible in situ transformation of pigmented tissues, including melanocytes, in C57BI/6 mice, by targeted drug delivery into the anterior or posterior segments of the eye to induce Cre-recombinase activity. These mice will be used to characterize the immune response to primary and metastatic uveal melanoma by monitoring SV40 Tag-specific immune responses. The immune response to SV40 Tag is well characterized in C57BI/6 mice and tetramers composed of soluble MHC Class I : SV40 Tag peptides are available along with an SV40 Tag specific TCR transgenic strain for studies aimed at determining the fate of CD8+ tumor-specific T cells in primary and metastatic uveal melanoma. In addition, these SV40 Tag transgenic mice will be a source for generating uveal melanoma cell lines. As the tyrosinase promoter is also active in cutaneous melanocytes, this transgenic mouse strain may also serve as a model of cutaneous melanoma which is inducible by drug delivery to the skin. Comparison of uveal and cutaneous melanoma cell lines derived from SV40 Tag transgenic mice may reveal novel molecules that control immune evasion and liver metastasis associated with uveal but not cutaneous melanoma. Understanding the mechanisms of immune evasion by uveal melanomas may lead to therapeutic approaches to promote tumor elimination. Furthermore, manipulation of these immune-suppressive mechanisms may be employed to inhibit T cell responses to prolong graft transplantation in the eye, for example, RPE transplants, or mitigate T cell mediated autoimmune uveitis.