Project 2: Combined CAR-T cell therapy

项目2：摘要 在B细胞恶性肿瘤中，通过过继性T细胞转移已报告了显著的临床应答 用对CD 19抗原特异性的嵌合抗原受体（CAR）重定向。然而，开发CAR-T 用于治疗包括胰腺导管腺癌（PDAC）的实体瘤是具有挑战性的，因为： (1)可被CAR-T靶向的PDAC相关抗原是有限的，通常不排他地表达 通过PDAC，并作为乘客，而不是作为肿瘤发生的驱动程序，允许抗原漂移;（2）CAR-T是 它们侵入富含基质的肿瘤如PDAC的能力有缺陷;（3）PDAC肿瘤微环境 (TME)是高度免疫抑制的。在本提案中，我们旨在解决这些关键问题。我们已经确定 B7-H3（CD 276）作为PDAC中嵌合抗原受体（CAR）T细胞的合适靶标。B7-H3是一种肿瘤 促进跨膜蛋白在60%-93%的PDAC、黑色素瘤、白血病、乳腺癌、 前列腺癌和卵巢癌，而在正常健康组织中观察到有限的表达。我们已经开发 并在PDAC的异种和免疫活性小鼠模型中测试了B7-H3.CAR-Ts，显示出抗肿瘤活性。 活动和安全。因此，在目标1中，我们建议在PDAC患者中开展I期临床研究， 评估B7-H3. CAR-T的安全性和抗肿瘤活性，其中还包括诱导型半胱天冬酶9（iC 9）作为 安全开关，用于在毒性情况下终止B7-H3.CAR-Ts的活性。在目标2中，我们建议在 临床前模型CAR-T，其中T细胞不仅通过CAR呈现肿瘤特异性 表达，但也被装备以克服PDAC的促结缔组织增生性质。具体而言，B7-H3.CAR-Ts 将被进一步改造以重新表达在CAR-Ts中有缺陷的乙酰肝素酶（HPSE） 用于临床使用。此外，我们将探讨是否葡萄糖调节蛋白的94 kDa（gp 96或 Grp 94），其是热休克蛋白（HSP）90家族（HSP 90 B1）的成员，也可用作 PDAC中的额外靶点，以防止当靶向一种单一抗原时由于抗原损失而导致的肿瘤逃逸。在 目的3：我们提出将巨噬细胞和髓源性抑制细胞（MDSC）重编程为非- 使用有效和口服生物可利用TAM RTK小分子抑制剂的免疫抑制状态 由北卡罗来纳州大学开发（IND #128236）。因此，我们将进行临床前研究，以评估 巨噬细胞和MDSC中的TAM RTK信号传导抑制是否有利于B7- H3.CAR-Ts.如果成功，该策略将被纳入拟议的I期临床试验的第二阶段。 用B7-H3.CAR-Ts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.