Project 2: Combined CAR-T cell therapy

项目2：摘要 过继转移T细胞治疗B细胞恶性肿瘤有显著的临床反应 重定向为针对CD19抗原的嵌合抗原受体(CAR)。然而，发展汽车-- 对于包括胰腺导管腺癌(PDAC)在内的实体肿瘤的治疗具有挑战性，因为： (1)car-ts靶向的pDAC相关抗原是有限的，通常不是唯一表达的。 通过PDAC，并充当乘客，而不是肿瘤发生的推动者，允许抗原漂移；(2)汽车是 侵袭PDAC等富含间质的肿瘤的能力有缺陷；(3)PDAC肿瘤微环境 (TME)具有高度的免疫抑制作用。在这项提案中，我们的目标是解决这些关键问题。我们已经确定了 B7-H3(CD276)作为PDAC嵌合抗原受体(CAR)T细胞的合适靶点。B7-H3是一种肿瘤 促进跨膜蛋白在PDAC、黑色素瘤、白血病、乳腺、 前列腺癌和卵巢癌，而在正常健康组织中表达有限。我们已经开发出 并检测了B7-H3CAR-ts在异种和免疫活性的PDAC小鼠模型中的抗肿瘤作用 活动和安全。因此，在目标1中，我们建议开展一项针对PDAC患者的I期临床研究 评估B7-H3CAR-TS的安全性和抗肿瘤活性，其中还包括诱导型caspase9(IC9)作为 安全开关，以终止B7-H3CAR-TS的活性，以防中毒。在目标2中，我们建议在 临床前模型，其中T细胞不是仅通过CAR呈现肿瘤特异性的 不仅可以表达，而且还可以克服PDAC的促结缔组织性质。具体地说，B7-H3.CAR-TS 将被进一步改造以重新表达在Car-ts中存在缺陷的乙酰肝素酶(HPSE) 为临床使用而产生。此外，我们将探索94 kDa的葡萄糖调节蛋白(gp96或gp96)是否 Grp94)，它是热休克蛋白(HSP)90家族的成员(HSP90B1)，也可用于 在PDAC中增加靶点，以防止当一个单一抗原被靶向时由于抗原丢失而导致的肿瘤逃逸。在……里面 目的3我们建议将巨噬细胞和髓系来源的抑制细胞(MDSC)重新编程为非 口服有效的RTK小分子抑制剂对免疫抑制状态的影响 由北卡罗来纳大学开发(IND#128236)。因此，我们将进行临床前研究，以评估 抑制巨噬细胞和骨髓间充质干细胞中的RTK信号是否有利于B7的抗肿瘤活性 H3.CAR-TS。如果成功，这一策略将被纳入拟议的I期临床的第二阶段 用B7-H3.CAR-Ts进行研究。

PROJECT 2: ABSTRACT Remarkable clinical responses have been reported in B-cell malignancies by adoptive transfer of T cells redirected with a chimeric antigen receptor (CAR) specific for the CD19 antigen. However, developing CAR-Ts for the treatment of solid tumors including pancreatic ductal adenocarcinoma (PDAC) is challenging because: (1) PDAC-associated antigens that are targetable by CAR-Ts are limited, generally not exclusively expressed by PDAC, and act as passengers, not as drivers of tumorigenesis, allowing for antigenic drift; (2) CAR-Ts are defective in their capacity to invade stroma-rich tumors such as PDAC; (3) PDAC tumor microenvironment (TME) is highly immunosuppressive. In this proposal we aim at solving these critical issues. We have identified B7-H3 (CD276) as a suitable target for chimeric antigen receptor (CAR) T cells in PDAC. B7-H3 is a tumor- promoting transmembrane protein aberrantly expressed in 60% to 93% of PDAC, melanoma, leukemia, breast, prostate and ovarian cancer, while limited expression is seen on normal healthy tissues. We have developed and tested B7-H3.CAR-Ts in xenogeneic and immunocompetent mouse models of PDAC showing antitumor activity and safety. Thus in Aim 1 we propose to develop a phase I clinical study in patients with PDAC to assess safety and antitumor activity of B7-H3.CAR-Ts that also include the inducible caspase9 (iC9) as a safety switch to terminate the activity of B7-H3.CAR-Ts in case of toxicity. In Aim 2 we propose to develop in preclinical models CAR-Ts in which T cells are not be only rendered tumor specific through the CAR expression, but are also equipped to overcome the desmoplastic nature of PDAC. Specifically, B7-H3.CAR-Ts will be further engineered to re-express the enzyme heparanase (HPSE), which is defective in CAR-Ts generated for clinical use. Furthermore, we will explore if the glucose-regulated protein of 94 kDa (gp96 or Grp94), which is a member of the heat shock protein (HSP) 90 family (HSP90B1) can also be used as additional target in PDAC to prevent tumor escape due to antigen loss when one single antigen is targeted. In Aim 3 we propose to reprogram macrophages and myeloid derived suppressor cells (MDSC) to a non- immunosuppressive state by using potent and orally bioavailable TAM RTK small molecule inhibitors developed at University of North Carolina (IND #128236). We will thus perform preclinical studies to evaluate whether TAM RTK signaling inhibition in macrophages and MDSC would favor the antitumor activity of B7- H3.CAR-Ts. If successful, this strategy will be included into a second phase of the proposed Phase I clinical study with B7-H3.CAR-Ts.