Stratification of Pancreatic Cancer Subpopulations for Effective Immunotherapy

由于胰腺导管腺癌(PDAC)的风险已经上升到更高的比率 在退伍军人中，相对于一般人口中的退伍军人，迫切需要制定有效的 退伍军人退伍军人治疗PDAC的治疗方法。最近，癌症免疫治疗已经取得了进展 在几种癌症中显示出巨大的前景，但在PDAC中没有。这其中的部分原因是 PDAC的异质性和缺乏针对个别肿瘤亚型的免疫治疗。 PDAC患者分层治疗仍处于初级阶段，是一种可靠的方法 去卷曲复杂的肿瘤成分来分层PDAC亚型还没有被认识到。 最近，我们参与了PDAC标本的全基因组测序，这为 根据基因组结构模式将PDAC分为四个亚型的依据 变化(《自然》，2016)。其中，免疫原性亚型占178例的30% TCGA数据库中的PDAC样本，其特征是免疫细胞上调 网络，这可能表明对免疫治疗的不同反应。此外， 表观基因组去卷积(EDEC)方法，最先由我们的合作者Dr。 Milosavljevic的研究小组，提供了关于肿瘤细胞类型组成和 细胞类型特异性基因表达(细胞代表2016)。应用于免疫原性亚型 PDAC肿瘤，EDEC揭示了免疫抑制的微环境，其特征是 在所有四种亚型中，Foxp3的表达最高。癌细胞落入免疫原性 亚型也表现出最高的间质蛋白(MSLN)表达。因此，我们假设 具有免疫原性的PDAC可能是对 MSLN病毒样颗粒(VLP)疫苗免疫治疗或联合治疗 VLP和一种免疫检查点抑制剂。我们将在临床前动物身上测试我们的假设 最能概括人类PDAC患者对免疫治疗反应的模型，包括 患者来源的肿瘤异种移植(PDX)和人源化小鼠模型。我们的初步数据 已经证明我们的抗MSLN VLP疫苗对MSLN高表达的PDX是有效的。 人源化NSG小鼠模型(PDX-HU-NSG)。基于我们强劲的初步结果，我们 建议开发一种有效的癌症免疫治疗方法，将三种高度联合 协同创新：(1)一种新的表观遗传去卷积方法来分层PDAC肿瘤； (2)PDX-Hu-NSG模型；(3)MSLN-VLP疫苗联合抗PD-1治疗 抗体。我们提出了两个具体目标。在目标1中，我们将确定免疫原性是否 在PDX-Hu-NSG模型中，PDAC亚型对MSLN-VLP疫苗有反应。在这里，我们将 用EDEC方法按亚型对VA PDAC进行分层，然后确定MSLN-VLP疫苗 人源化PDX小鼠模型中特定PDAC亚组的疗效。在目标2中，我们将 确定与抗PD-1抗体联合治疗是否能增强MSLN VLP疫苗 肿瘤-腐殖体模型中的反应和有效性。我们还将确定特定的肿瘤浸润性 负责有效的联合治疗的细胞的子集。此外，潜力 联合治疗的副作用也将被评估。我们的发现将为临床前提供 一种新型精密免疫疗法治疗慢性阻塞性肺疾病的疗效评价 使小鼠人性化，而不会将患者置于危险之中。该项目将提供对 分子、细胞和组织水平的治疗反应，朝着改善的关键一步 通过患者分层治疗的PDAC的结果。

As the risk for pancreatic ductal adenocarcinoma (PDAC) has increased to a higher rate in veterans relative to that in the general population, there is an urgent need to develop effective therapies to treat PDAC for veterans in the VA system. Recently, cancer immunotherapy has shown great promise in several cancers, but not in PDAC. Part of the reason for this is the heterogeneity of PDAC and lack of tailoring of immunotherapy to individual tumor subtypes. PDAC patient stratification for therapy remains in its infancy, and a reliable method to deconvolute complex tumor composition to stratify PDAC subtypes has not been recognized. Recently, we participated in whole genome sequencing of PDAC specimens, which provides the basis for classifying PDAC into four subtypes based upon patterns of genomic structural variation (Nature, 2016). Among these, the immunogenic subtype accounts for 30% of 178 PDAC samples in the TCGA database and is characterized by upregulated immune cell networks, which could indicate differential responses to immunotherapy. In addition, the Epigenomic Deconvolution (EDec) method, first developed by our co-investigator Dr. Milosavljevic’s group, provides valuable information about cell type composition of tumors and cell-type specific gene expression (Cell Rep. 2016). When applied to immunogenic subtype PDAC tumors, EDec reveals an immunosuppressive microenvironment characterized by the highest Foxp3 expression among all four subtypes. Cancer cells falling into the immunogenic subtype also show the highest mesothelin (MSLN) expression. Therefore, we hypothesize that PDACs with an immunogenic profile could be a target subgroup that is responsive to immunotherapy either by MSLN virus-like particle (VLP) vaccination or combination therapy of VLPs and an immune checkpoint inhibitor. We will test our hypothesis in pre-clinical animal models that best recapitulate human PDAC patient’s response to immunotherapy, including patient-derived tumor xenografts (PDX) and humanized mouse models. Our preliminary data have shown that our anti-MSLN VLP vaccine is effective against MSLN-high expressing PDX in a humanized NSG mouse model (PDX-hu-NSG). Based on our strong preliminary results, we propose to develop an effective cancer immunotherapeutic approach by combining three highly synergistic innovations: (1) A novel epigenetic deconvolution method to stratify PDAC tumors; (2) PDX-hu-NSG models; and (3) Combination therapy of MSLN-VLP vaccine plus anti-PD-1 antibody. We propose two specific aims. In Aim 1, we will determine whether the immunogenic subtype of PDAC is responsive to MSLN-VLP vaccine in PDX-hu-NSG model. Here, we will use EDec method to stratify VA PDACs by subtype and then determine MSLN-VLP vaccine efficacy in specific PDAC subgroups in humanized PDX mouse model. In Aim 2, we will determine whether combination therapy with anti-PD-1 Ab enhances MSLN VLP vaccine responses and efficacy in onco-humice model. We will also determine specific tumor infiltrating subset of cells that are responsible for the effective combination therapy. Furthermore, potential side-effect of the combination therapy will also be evaluated. Our findings will provide preclinical evaluation of the therapeutic efficacy of an innovative precision immunotherapy for PDAC in humanized mice without putting patients at risk. The project will provide understanding of molecular, cellular, and tissue-level responses to therapy, a key step towards improved outcomes in PDAC through patient stratification for therapy.