Project 4:Targeting M2-like Macrophages and MDSC with Myelolytic-Virotherapy

摘要-项目4： 复发或转移性实体瘤的儿科患者的治愈率仍然低得令人无法接受。癌 免疫疗法大有可为，但数十项令人失望的研究突显了我们对免疫疗法的相对无知 了解实体瘤内的免疫抑制微环境。因为他们在 介导免疫抑制的肿瘤相关巨噬细胞(TAM)，通常被极化为所谓的M2- 类似的免疫抑制表型和髓系来源的抑制细胞(MDSC)被认为是重要的 治疗靶点。我们已经找到了一种临床上可行的策略，可以同时减少TAMS/MDSC(我们称为 “溶髓”)和极化微环境(通过溶瘤病毒感染)，产生显著的抗肿瘤作用 功效。我们推测，以和骨髓间充质干细胞为靶点，结合溶髓和促髓鞘激素治疗。 炎症治疗激活固有的抗肿瘤机制，导致癌症消退和 重塑实体肿瘤微环境，使其更适合细胞免疫治疗。在AIM 1、我们将确定髓溶解-病毒疗法联合驱动肿瘤的机制(S) 回归。我们将使用荧光纳米钻石等新技术来确定对先天的影响 免疫细胞吞噬肿瘤细胞。我们将利用基因组学和免疫监测共享资源 核心B由伊莱恩·马迪斯博士指导，用飞行时间质谱仪和单个 细胞转录学以确定对免疫细胞组成和极化的影响。我们还将利用 确定MDSC缺失是否对肿瘤消退起关键作用的获得和功能丧失方法 用溶髓病毒疗法。我们还将在异种移植和免疫活性模型中测试联合疗法。 以确定其普适性(骨肉瘤、尤文肉瘤、横纹肌肉瘤、 神经母细胞瘤)。在目标2中，我们将确定髓溶解病毒疗法对T细胞介导的 免疫疗法。我们将检查单独的髓溶解和联合病毒治疗对疗效的影响。 抗肿瘤T细胞在T细胞耗尽环境中与CAR-T细胞的关系(与项目1负责人Lee和共同 调查员王若宁，国际解联U01成员)。我们将与核心B合作，检查对T细胞的影响 使用TCR测序进行克隆。在目标3中，我们将确定联合髓溶解-病毒治疗 提高以NK为基础的细胞疗法的疗效。我们将与项目1负责人李院长和 项目2领导米奇·开罗研究对过继NK和CAR-NK细胞治疗的影响。总体而言，有了这个 我们将进一步阐明、测试和开发调节肿瘤微环境的策略，以促进 作为癌症治疗的先天免疫细胞。我们的发现可能适用于广泛的儿科癌症小组 因此，它非常符合儿科免疫疗法发现和发展网络的目标。

Abstract - Project 4: Cure rates for pediatric patients with relapsed or metastatic solid tumors remain unacceptably low. Cancer immunotherapies hold great promise, but scores of disappointing studies highlight our relative ignorance in understanding the immunosuppressive microenvironment within solid tumors. Because of their central role in mediating immunosuppression, tumor associated macrophages (TAMs), typically “polarized” to a so-called M2- like immunosuppressive phenotype, and myeloid-derived suppressor cells (MDSC), are thought to be important therapeutic targets. We have found a clinically viable strategy that simultaneously reduces TAMs/MDSC (we dub “myelolytic”) and polarizes the microenvironment (via oncolytic virus infection), resulting in significant antitumor efficacy. We hypothesize that targeting TAM and MDSC by combining “myelolytic” therapies with pro- inflammatory therapies activates innate antitumor mechanisms that cause cancer regressions and reshapes the solid tumor microenvironment to be more permissive to cellular immunotherapies. In aim 1, we will determine the mechanism(s) by which combined myelolytic-virotherapy drives tumor regressions. We will use novel technologies such as fluorescent nanodiamonds to determine effects on innate immune cell phagocytosis of tumor cells. We will utilize the Genomics & Immune Monitoring Shared Resource Core B directed by Dr. Elaine Mardis to conduct flow cytometry with time-of-flight mass spectrometry and single cell transcriptomics to determine the effects on immune cell composition and polarization. We will also utilize gain- and loss-of-function approaches to determine if loss of MDSC are critical for enabling tumor regressions with myelolytic-virotherapy. We will also test combination therapies in xenograft and immunocompetent models of other cancer types to confirm its generalizability (osteosarcoma, Ewing sarcoma, rhabdomyosarcoma, neuroblastoma). In aim 2, we will determine the effects of myelolytic-virotherapy on T cell-mediated immunotherapies. We will examine the effect of myelolysis alone and combined with virotherapy on the efficacy of antitumor T cells in a T cell exhaustion setting and with CAR-T cells (with Project 1 Leader Dean Lee and co- investigator Ruoning Wang, PI-DDN U01 member). We will work with Core B to examine the effects on T cell clonality using TCR sequencing. In aim 3, we will determine whether combined myelolytic-virotherapy enhances the efficacy of NK-based cellular therapies. We will work with Project 1 Leader Dean Lee and Project 2 Leader Mitch Cairo to study the effects on adoptive NK and CAR-NK cell therapy. Overall, with this project we will further elucidate, test and develop strategies to modulate the tumor microenvironment to facilitate innate immune cells as cancer therapy. Our findings may be applicable across a broad panel of pediatric cancer types and thus fits well into the aims of the Pediatric Immunotherapy Discovery and Development Network.