Vaccine Targeting of RCC Blood Vessels to Promote TME Normalization and Enhance TIL Recruitment

摘要 尽管肾细胞癌通常被归类为免疫原性肿瘤，但最近的分析研究表明， 这种癌症中存在 CD8 TIL 是预后不良的指标。这些发现强调 了解肿瘤微环境中免疫背景/免疫细胞网络的重要性 解释肿瘤免疫的运行状态及其对疾病进展和反应的可能影响 到介入治疗。事实上，如果人们考虑的是有组织的 CD8 T 细胞簇和成熟的 DC- 肿瘤中三级淋巴结构 (TLS) 内的 LAMP 树突状细胞 (DC)，这些淋巴“器官”是 RCC 患者总生存率/PFS 的积极预后指标。肿瘤相关 TLS 已被 建议作为表现出较少耗尽表型的浸润淋巴细胞的免疫“绿洲”，以及 作为原位 DC 介导的多样化治疗性 CD8 T 细胞库交叉启动的位点。我们有 最近表明，针对肿瘤相关血管抗原（TBVA）的疫苗接种会导致血管 正常化（VN；即血管修剪、减少血管渗漏/缺氧/间质液压力）和去 小鼠和人类肿瘤内 TLS 的新开发对基于介入疫苗的反应 免疫疗法。值得注意的是，我们还观察到这些疫苗的抗肿瘤功效表现出 深刻的性别/性二态性，女性（或阉割的男性）与完整的男性相比，反应率更高， 表明性类固醇及其受体的调节作用。我们的中心假设是：i.) 促进 RCC 中 VN 的联合免疫疗法将促进 TLS 的发展和生成 具有广泛反应性的治疗性 CD8 T 细胞库，表现出卓越的“适应性”和抗肿瘤功效，ii.) 通过联合施用雄激素合成/AR可以避免疫苗接种的性别二态性反应 对手。鉴于 ccRCC 的男性：女性发病率为 2:1，后面这些研究预计将显着 扩大 TBVA 靶向疫苗针对 RCC 的治疗效用。我们首先将进行探索性的 确定针对 TBVA 口服低剂量的自体 αDC1/肽疫苗的影响的临床试验 卡博替尼对最近诊断的原发性肿瘤患者的 VN、TLS 形成和肿瘤浸润 T 细胞适应性的影响 在计划的手术切除（目标 1）之前进行 ccRCC，然后建立动物模型来检验假设 i.) 能够在鼠肾细胞癌 (RENCA, RENCA.VHL-/-) 肿瘤中促进 VN 的药物将与 针对 RCC 和/或 TBVA 抗原的疫苗 /- 检查点封锁促进 TLS 的发展， 改善肿瘤浸润 T 细胞 (TIL) 适应性、扩展 TIL 库和卓越的治疗效果（Aim 2) 和 ii.) 能够中断雄激素合成/雄激素受体信号传导的药物将改善 VN 诱导免疫疗法对携带 RCC 肿瘤的雄性/雌性 BALB/c 小鼠的治疗效果（目标 3）。

ABSTRACT Although RCC is typically classified as an immunogenic tumor, recent profiling studies instead suggest that presence of CD8+ TIL in this form of cancer is an indicator of poor prognosis. These findings emphasize the importance of appreciating immune context/immune cell networking in the tumor microenvironment when interpreting the operational status of tumor immunity and its likely impact on disease progression and response to interventional therapy. Indeed, if one instead considers organized clusters of CD8+ T cells and mature DC- LAMP+ dendritic cells (DC) within tertiary lymphoid structures (TLS) in tumors, these lymphoid “organs” are positive prognostic indicators for overall survival/PFS in RCC patients. Tumor-associated TLS have been suggested to serve as an immune “oasis” for infiltrating lymphocytes exhibiting less-exhausted phenotypes, and as sites for in situ DC-mediated cross-priming of a diversified therapeutic CD8+ T cell repertoire. We have recently shown that vaccination against tumor-associated blood vessel antigens (TBVA) results in vascular normalization (VN; i.e. vascular trimming, reduced vascular leak/hypoxia/interstitial fluid pressure) and the de novo development of TLS within tumors in mice and humans responding to interventional vaccine-based immunotherapy. Remarkably, we have also observed that the anti-tumor efficacy of these vaccines exhibits profound gender/sexual dimorphism, with higher response rates in females (or castrated males) vs. intact males, suggesting a regulatory role for sex steroids and their receptors. Our central hypotheses are that: i.) combination immunotherapy promoting VN in RCC will enhance TLS development and the generation of a broadly-reactive therapeutic CD8+ T cell repertoire exhibiting superior “fitness” and anti-tumor efficacy, and ii.) gender dimorphic response to vaccination can be circumvented by co-administration of androgen synthesis/AR antagonists. Given a 2:1 male:female incidence of ccRCC, these latter studies are expected to dramatically expand the therapeutic utility of TBVA-targeted vaccines against RCC. We will initially perform an exploratory clinical trial to determine the impact of an autologous αDC1/peptide vaccine targeting TBVA + oral low-dose cabozantinib on VN, TLS formation and tumor-infiltrating T cell fitness in patients with recently-diagnosed primary ccRCC prior to planned surgical resection (Aim 1), before then pursuing animal models to test the hypotheses that i.) agents capable of promoting VN in murine RCC (RENCA, RENCA.VHL-/-) tumors will synergize with vaccines targeting RCC and/or TBVA antigens +/- checkpoint blockade in promoting the development of TLS, improved tumor-infiltrating T cell (TIL) fitness, an expanded TIL repertoire and superior therapeutic benefit (Aim 2) and ii.) agents capable of interrupting androgen synthesis/androgen receptor-signaling will improve therapeutic efficacy of VN-inducing immunotherapies in male/female BALB/c mice bearing RCC tumors (Aim 3).