IMPROVING T CELL THERAPY OF NASOPHARYNGEAL CANCER

潜伏性EB病毒（EBV）感染与鼻咽癌（NPC）有关， 表达EBV抗原LMP 1和LMP 2，两者都是免疫治疗的潜在靶点。临床研究 鼻咽癌中的EBV特异性细胞毒性T细胞（EBV-CTL）已经取得了有希望的结果，包括一些 完全应答，但它们的功效是有限的，因为通过标准方法产生的EBV-CTL是 1)由对NPC中表达的EBV蛋白LMP 1和LMP 2不反应的T细胞克隆占主导地位，2） 输注后不能显著扩增，3）对NPC采用的免疫逃避策略敏感 如MHC I类分子表达下调和调节性T细胞（TCLs）的存在。 肿瘤环境，和4）在NPC沉积物内的缺氧区域功能失调。我们的核心假设 克服这些限制将增强输注的CTL的抗肿瘤活性，并改善 治疗结果因此，我们将制备EBV-LMP 1和LMP 2特异性CTL（LMP-CTL），并评估 使用临床试验或异种移植模型来增强其活性的三种策略。目标1扩展了我们目前的 LMP-CTL联合CD 45单克隆抗体治疗鼻咽癌的I期临床试验 增强体内CTL扩增并提高疾病应答率。在目标2中，我们将表达嵌合的 LMP-CTL中对CD 70特异性的抗原受体（CAR）。CD 70在EBV阳性NPC中过表达， 因此，修饰的CTL应该能够通过MHC I类限制性和非限制性两者杀死NPC细胞， 途径，增加它们在我们的异种移植模型中的治疗效果。此外，我们还将 在CAR中共刺激分子的信号转导内域，并测试这些修饰是否使 对NPC中存在的TcR具有抗性的CAR-LMP-CTL。在目标3中，我们将利用我们以前的观察结果 表明由缺氧诱导因子（HIF-IL 2）调节的IL-2基因的表达可使CTL 耐缺氧。我们将检测HIF-IL 2表达的细胞持久性、增殖和功能， LMP-CTL在NPC肿瘤内的缺氧区域，并确定它们是否产生增强的抗肿瘤活性。 这些目标与项目1-3中的目标相辅相成，但不重叠，因此，我们的 研究可以迅速融入该计划中正在其他肿瘤中进行测试的策略， 反之亦然Lav总结：身体对癌症的免疫防御经常失败，因为 恶性肿瘤不诱导或主动抑制免疫。我们将努力克服这些限制， 设计杀伤T细胞以识别癌细胞（LMP 1和LMP 2）上的结构，并抵抗癌细胞的侵袭。 由肿瘤细胞环境施加的防御。然后将在患有以下疾病的患者中测试T细胞的作用： 鼻咽癌（NPC）。

Latent Epstein-Barr virus (EBV) infection is associated with nasopharyngeal carcinoma (NPC), which expresses the EBV antigens LMP1 and LMP2, both potential targets for immunotherapy. Clinical studies with EBV-specific cytotoxicT cells (EBV-CTLs) in NPC have already yielded promising results, including some complete responses, but their efficacy is limited because the EBV-CTL generated by standard methods are 1) dominated by T-cell clones not reactive to the EBV proteins LMP1 and LMP2 expressed in NPC, 2) cannot expand significantly after infusion, 3) are sensitive to immune evasion strategies employed by NPCs such as downregulation of MHC class I expression and the presence of regulatory T cells (Tregs) in the tumor environment, and 4) are dysfunctional in areas of hypoxia within NPC deposits. Our central hypothesis is that overcoming these limitations will enhance the antitumor activity of infused CTLs and improve treatment outcome. Thus, we will prepare EBV-LMP1 and LMP2-specific CTLs (LMP-CTLs) and evaluate three strategies to enhance their activity using a clinical trial or a xenograft model. Aim 1 extends our current Phase I clinical trials in NPC by combining LMP-CTL with lymphodepleting CD45 monoclonal antibodies to augment CTL expansion in vivo and improve disease response rates. In Aim 2, we will express a chimeric antigen receptor (CAR) specific for CD70 in LMP-CTLs. CD70 is overexpressed in EBV-positive NPCs, and the modified CTLs should thus be able to kill NPC cells through both MHC class l-restricted and unrestricted pathways, increasing their therapeutic effectiveness in our xenograft model. Moreover, we will incorporate signaling endodomains from costimulatory molecules in the CAR and test whether these modifications make the CAR-LMP-CTL resistant to Tregs present in NPC. In Aim 3, we will exploit our previous observations showing that expression of the IL-2 gene regulated by the hypoxia inducible factor (HIF-IL2) can render CTL resistant to hypoxia. We will measure cellular persistence, proliferation and function of HIF-IL2 expressing LMP-CTL in hypoxic areas within NPC tumors, and determine, if they produce enhanced antitumor activity. These aims complement but do not overlap with those in projects 1-3, such that advances emerging from our research could be rapidly assimilated into strategies being tested in other tumors within this program and vice versa. Lav Summary: The body's immune defenses against cancers often fail because the malignancies do not induce or actively inhibit immunity. We will try to counteract these limitations by engineering killer T cells to recognize structures on cancer cells (LMP1 and LMP2) and to resist the defenses imposed by the tumor cell environment. The effects of the T cells will then be tested in patients with nasopharyngeal carcinoma (NPC).