Preclinical Optimization of Melanoma Adoptive T Cell Immunotherapy

描述（由申请人提供）： 定向免疫系统对抗肿瘤细胞的免疫策略继续为晚期黑色素瘤患者带来巨大希望。常规治疗方案的缺乏以及临床免疫治疗的复杂性和不一致性促使科学模型的发展，以确定改善免疫治疗的方法。到目前为止，这些模型已经采用了黑素瘤特异性T细胞群，这些细胞群已经被激活并离体扩增，用于过继转移到携带黑素瘤肿瘤的淋巴细胞耗尽的宿主中。尽管设计用于模拟人类受试者中使用的实验过继免疫疗法的范例，但这些模型的复杂性使我们难以精确表征过继转移的黑素瘤特异性T细胞和黑素瘤肿瘤之间发生的体内相互作用。我们的实验室已经开发了一个简单的定量动物模型的黑色素瘤诱导的T细胞抑制，以证明在体内暴露于不断增长的黑色素瘤肿瘤削弱了T细胞的能力，通过提高他们的易感性进行抗原驱动的增殖性扩增细胞凋亡。T细胞反应性的这种改变从根本上重塑了活化T细胞稳态的整个谱，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抗性。在本提案中，我们借鉴了之前的经验，引入了新的、简化的黑色素瘤过继性T细胞免疫治疗模型，以测试一个中心假设：黑色素瘤过继性免疫治疗的功效可以通过使用记忆T细胞来优化。在第一系列实验中，我们将检验第一个子假设： 过继转移的黑素瘤特异性T细胞的体内耐久性受到黑素瘤诱导的T细胞凋亡上调的损害。我们将研究过继转移的T细胞群体在体内的命运，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，我们将测试第二个子假设：记忆T细胞是黑色素瘤过继免疫治疗的最佳介质，因为过继转移后生存和靶向黑色素瘤抗原的能力增强。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、中枢记忆T细胞和效应记忆T细胞）过继转移的黑素瘤特异性T细胞的体内持久性，以及它们浸润黑素瘤肿瘤、诱导肿瘤消退和促进肿瘤免疫的能力。从那里，我们将测试第三个子假设：当内源性黑色素瘤特异性T细胞反应被保留时，过继免疫治疗更有效。我们将采用我们实验室中使用的高度定量测定来确定内源性黑素瘤特异性T细胞应答如何受到过继免疫治疗的影响，并将确定保留和增强这些内源性应答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的实验中，我们将测试第四子假设：黑色素瘤特异性记忆T细胞可以被收获并扩增到允许基于记忆T细胞的过继免疫疗法的临床实现的数量。在这里，我们将研究人类黑色素瘤肿瘤，以验证记忆T细胞的生物学优势可以投入临床使用。这最后一块将使我们能够开始下一阶段的调查：一个临床试验，介绍一种新的和关键形式的癌症治疗。总之，我们提出了一系列的实验，通过这些实验，过继性T细胞免疫治疗的生物学基础可以被合理和批判性地探索。我们期望这项工作将使我们能够充分实现这种迫切需要的治疗患有黑色素瘤的退伍军人的巨大潜力。 公共卫生相关性： 黑色素瘤的发病率比任何其他癌症的发病率增加得更快;然而，目前可用于患有晚期黑色素瘤的退伍军人的少数治疗选择提供了巨大的毒性，临床益处极小或无。利用患者自身免疫系统对抗黑色素瘤的实验性努力已经取得了有趣但初步的成功。我们的实验室已经开发出一种实验方法来剖析免疫疗法的生物学基础。我们概述了一系列实验，这些实验将教会我们（1）黑色素瘤肿瘤如何影响黑色素瘤特异性在过继转移后持续存在的能力，（2）哪些免疫细胞在介导免疫治疗中最有效，（3）当前形式的黑色素瘤治疗如何与免疫治疗协同作用以最大限度地提高临床效益，以及（4）将这些发现转化为人类研究的方法。简而言之，我们将学习如何实现黑色素瘤免疫治疗的巨大前景。

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. PUBLIC HEALTH RELEVANCE: The incidence of melanoma is increasing faster than that of any other cancer; yet the few treatment options currently available for Veterans with advanced melanoma offer enormous toxicity with minimal-to-no clinical benefit. Experimental efforts to fight melanoma using the patient's own immune system have yielded intriguing but preliminary successes. Our laboratory has developed an experimental way to dissect the biological underpinnings of immunotherapy. We outline a series of experiments that will teach us (1) how melanoma tumors affect the ability of melanoma-specific to persist following adoptive transfer, (2) which immune cells would be most effective in mediating immunotherapy, (3) how current forms of melanoma treatment may synergize with immunotherapy to maximize clinical benefit, and (4) ways to translate these findings into human studies. In short, we will learn ways in which the enormous promise of melanoma immunotherapy may be actualized.