Age related ubiquitin defect on T-cell response to tumor

描述（由申请人提供）：本修订提案的总体目标是确定含有F-box和WD40结构域的新型乳腺肿瘤抗原的生物学效应，重点是其在年龄和T细胞依赖性肿瘤生长易感性中的作用。我们已经鉴定出一种新的人类乳腺肿瘤抗原（HBTA1），它能强烈抑制老年小鼠的T细胞增殖，而不是年轻小鼠。用HBTA1免疫2岁龄bxd12小鼠可在16岁龄时抵抗肿瘤攻击。对小鼠同源HBTA1 （mHBTA1）进行蔗糖梯度纯化，然后对纯化的样品进行电镜检查，发现mHBTA1被包装在TS/ a肿瘤的外泌体中。TS/A外泌体mHBTA1强烈抑制老年BXD12小鼠分离的T细胞的增殖，而不是年轻BXD12小鼠。T细胞在TS/A外泌体存在下的增殖能力与外泌体mHBTA1的泛素化状态相关。我们的目标是：(1)确定mHBTA1的泛素化是否与肿瘤生长的易感性和肿瘤特异性细胞毒性t细胞反应相关。我们将用泛素化的外泌体mHBTA1免疫老年小鼠，以确定其对增强肿瘤生长的保护作用。同时，我们将确定TS/A外泌体中内源性泛素化mHBTA1的产生是否与肿瘤易感性相关。(2)利用siRNA技术确定敲除肿瘤细胞外泌体mHBTA1是否足以逆转TS/A外泌体介导的T细胞增殖抑制，或者是否需要其他外泌体蛋白。(3)为了确定我们最近发现的年龄依赖性T细胞因子是否在外泌体mHBTA1泛素化中发挥作用，从而使mHBTA1介导的T细胞活化抑制失活；我们将进一步确定TS/A外泌体mHBTA1与t细胞因子相互作用的途径。(4)确定年龄相关t细胞因子是否调控人乳腺肿瘤外泌体HBTA1泛素化，并进一步确定其与年龄相关乳腺癌发病率的可能关联。所产生的数据应阐明肿瘤外泌体和外泌体mHBTA1在年龄依赖性和T细胞依赖性乳腺癌发展中的作用的细胞和分子基础。

DESCRIPTION (provided by applicant): The overall goal of this revised proposal is to determine the biologic effects of a novel breast tumor antigen containing F-box and WD40 domains, with an emphasis on its roles in age- and T cell-dependent susceptibility to tumor growth. We have identified a novel human breast tumor antigen (HBTA1) that strongly inhibits proliferation of T cells from aged, but not young, mice. Immunization of 2-mo-old BXD 12 mice with HBTA1 protects against the tumor challenge at 16-mo-of-age. Sucrose gradient purification of a mouse homologue HBTA1 (mHBTA1) followed by electromicroscope examination of the purified samples led to the realization that mHBTA1 is packed in the exosomes of the TS/A tumors. The TS/A exosomal mHBTA1 strongly inhibits the proliferation of T cells isolated from aged, but not young, BXD12 mice. The ability of T cells to proliferate in the presence of TS/A exosomes is correlated with the ubiquitination status of exosomal mHBTA1. Our aims are (1) To determine if ubiquitination of mHBTA1 is correlated with susceptibility to tumor growth and the tumor-specific cytotoxic T-cell response. Aged-mice will be immunized with ubiquitinated exosomal mHBTA1 to determine its effects on enhancement of protection against the tumor growth. In parallel, we will determine if the production of endogenous ubiquitinated mHBTA1 in TS/A exosomes is correlated with the tumor susceptibility. (2) To use siRNA technology to determine if knockout of exosomal mHBTA1 of tumor cells is sufficient to reverse the inhibition of T cell proliferation mediated by TS/A exosomes or whether other exosomal proteins are required. (3) To determine if the age-dependent T cell factors we recently identified play a role in ubiquitination of exosomal mHBTA1, and thus inactivation of mHBTA1-mediated inhibition of T-cell activation; we will further determine the pathway by which TS/A exosomal mHBTA1 interacts with T-cell factors. (4) To determine if an age-related T-cell factor(s) regulates the ubiquitination of exosomal HBTA1 of human breast tumors, and, further to determine its possible association with the age-related incidence of breast cancers. The data generated should elucidate the cellular and molecular basis for the role of tumor exosomes and exosomal mHBTA1 in the development of age- and T cell-dependent breast cancer.