Preclinical Optimization of Melanoma Adoptive T Cell Immunotherapy

描述(由申请人提供)： 免疫治疗策略使免疫系统适应肿瘤细胞，继续为晚期黑色素瘤患者带来巨大希望。常规治疗选择的匮乏以及临床免疫治疗的复杂性和不一致性促使了科学模型的发展，以确定改进免疫治疗的方法。到目前为止，这些模型已经采用了黑色素瘤特异性T细胞群体，这些T细胞群体已经被激活并在体外扩增，用于过继转移到携带黑色素瘤的淋巴耗竭宿主中。虽然这些模型的设计是为了模仿在人类受试者中使用的实验性过继免疫疗法的范例，但这些模型的复杂性混淆了我们准确描述过继转移的黑色素瘤特异性T细胞和黑色素瘤肿瘤之间发生的体内相互作用的能力。我们的实验室已经建立了一个简单的黑色素瘤诱导T细胞抑制的定量动物模型，以证明在体内暴露于不断生长的黑色素瘤肿瘤会通过增加T细胞对凋亡细胞死亡的敏感性来削弱T细胞经历抗原驱动的增殖增殖的能力。这种T细胞反应性的改变从根本上重塑了激活的T细胞稳态的整个光谱，但有一个有趣的例外：记忆T细胞似乎对这种黑色素瘤诱导的抑制具有独特的抵抗力。在这项建议中，我们借鉴了我们以前的经验，引入了新的、简化的黑色素瘤过继T细胞免疫治疗模型，以检验一个核心假设：使用记忆T细胞可以优化黑色素瘤过继免疫治疗的疗效。在第一系列实验中，我们将检验第一个子假说： 过继转移的黑色素瘤特异性T细胞在体内的持久性因黑色素瘤诱导的T细胞凋亡上调而受损。我们将检查体内过继转移的T细胞群体的命运，以表征黑色素瘤如何影响黑色素瘤特异性T细胞治疗群体的持续能力。在接下来的一系列实验中，我们将检验第二个假设：记忆T细胞是黑色素瘤过继免疫治疗的最佳介质，因为在过继转移后，记忆性T细胞具有更强的生存能力和靶向黑色素瘤抗原的能力。我们将比较过继转移后不同成熟阶段(静息T细胞、急性效应T细胞、未分选记忆T细胞、中央记忆T细胞和效应记忆T细胞)过继转移的黑色素瘤特异性T细胞在体内的持久性，以及它们渗透黑色素瘤、诱导肿瘤消退和促进肿瘤免疫的能力。从那时起，我们将检验第三个假设：当内源性黑色素瘤特异性T细胞反应得到保留时，过继免疫治疗更有效。我们将使用我们实验室中使用的高定量分析来确定过继免疫治疗如何影响内源性黑色素瘤特异性T细胞反应，并将确定保存和增强这些内源性反应的治疗努力是否会促进过继免疫治疗的疗效。在第四个也是最后一个系列实验中，我们将检验第四个假设：黑色素瘤特异性记忆T细胞可以被获取和扩增到允许临床实现基于记忆T细胞的过继免疫治疗的数量。在这里，我们将通过检测人类黑色素瘤肿瘤来验证记忆T细胞的生物学优势可以应用于临床。这最后一项工作将使我们能够开始下一阶段的研究：介绍一种新的和关键的癌症治疗形式的临床试验。综上所述，我们提出了一系列实验，通过这些实验，可以理性地和批判性地探索过继T细胞免疫治疗的生物学基础。我们期望，这项工作将使我们能够充分发挥这种迫切需要的治疗黑色素瘤退伍军人的巨大潜力。

DESCRIPTION (provided by applicant): Immunotherapeutic strategies to orient the immune system against tumor cells continue to hold great promise for patients with advanced melanoma. The paucity of conventional treatment options and the complexity and inconsistency of clinical immunotherapy have motivated the development of scientific models to identify ways to improve immunotherapy. Thus far, these models have employed melanoma-specific T cell populations that have been activated and expanded ex vivo for adoptive transfer into lymphodepleted hosts bearing melanoma tumors. Although designed to mimic paradigms of experimental adoptive immunotherapy used in human subjects, the complexity of these models has obfuscated our ability to precisely characterize the in vivo interaction that takes place between adoptively transferred melanoma-specific T cells and melanoma tumors. Our laboratory has developed a simple quantitative animal model of melanoma-induced T cell suppression to demonstrate that in vivo exposure to growing melanoma tumors weakens the ability of T cells to undergo antigen-driven proliferative expansion by heightening their susceptibility to apoptotic cell death. This alteration of T cell responsiveness fundamentally reshapes the entire spectrum of activated T cell homeostasis with one interesting exception: memory T cells appear to be uniquely resistant to this melanoma- induced suppression. In this proposal, we have drawn on our previous experience to introduce new, simplified models of melanoma adoptive T cell immunotherapy to test a central hypothesis: that the efficacy of melanoma adoptive immunotherapy can be optimized with the use of memory T cells. In the first series of experiments, we will test a first subhypothesis: that the in vivo durability of adoptively transferred melanoma-specific T cells is impaired by melanoma-induced upregulation of T cell apoptosis. We will examine the fate of adoptively transferred T cell populations in vivo to characterize how melanoma influences the ability of therapeutic populations of melanoma-specific T cells to persist. In the next series of experiments, we will test a second subhypothesis: that memory T cells are optimal mediators of melanoma adoptive immunotherapy because of an enhanced ability to survive and target melanoma antigens following adoptive transfer. We will compare the in vivo persistence of adoptively transferred melanoma-specific T cells in various stages of maturation (resting T cells, acute effector T cells, unsorted memory T cells, central memory T cells, and effector memory T cells) following adoptive transfer, as well as their abilities to infiltrate melanoma tumors, induc tumoral regression, and promote tumoral immunity. From there, we will test a third subhypothesis: that adoptive immunotherapy is more effective when endogenous melanoma-specific T cell responses are preserved. We will employ highly quantitative assays used in our laboratory to determine how endogenous melanoma-specific T cell responses are affected by adoptive immunotherapy, and will determine if therapeutic efforts to preserve and enhance those endogenous responses promote the efficacy of adoptive immunotherapy. In the fourth and final series of experiments, we will test a fourth subhypothesis: that melanoma-specific memory T cells can be harvested and expanded to quantities that will permit the clinical realization of memory T cell-based adoptive immunotherapy. Here, we will examine human melanoma tumors to verify that the biological advantages of memory T cells can be put to clinical use. This final piece will enable us to begin the next phase of investigation: a clinical rial to introduce a novel and critical form of cancer treatment. In summary, we are proposing a series of experiments with which the biological underpinnings of adoptive T cell immunotherapy may be rationally and critically explored. It is our expectation that this work will allow us to fuly actualize the enormous potential of this desperately needed treatment for veterans afflicted with melanoma.