(PQB-3) Driver gene-induced inflammation in pancreatic cancer development

描述（由申请人提供）：免疫系统识别癌细胞与其来源的正常组织之间的微小蛋白质差异。免疫疗法（癌症疫苗和免疫调节剂）是一种新兴的方式，可以教育免疫系统识别这些差异。大多数癌症在开始时是潜伏的，并在10至30年内发展，因此很难知道何时最好接种疫苗以及接种多长时间。随着癌症遗传和表观遗传变化的最新进展，现在有可能将从病毒靶向疫苗中学到的原理应用于针对早期遗传变化（驱动基因）诱导的途径的免疫疗法的开发，这些变化对癌症的发生至关重要。癌症的发展是一个漫长的过程，涉及遗传、表观遗传和炎症信号通路之间的相互联系，这些通路在靶器官内不断变化，因为细胞从正常转变为癌前病变，再转变为浸润性癌症。在胰腺癌（PDAC）中，新出现的证据表明，这些早期变化诱导肿瘤耐受（抗炎）免疫环境，包括促结缔组织增生的成纤维细胞成分，以及产生细胞因子的各种类型的免疫抑制基质细胞，这些细胞因子抑制抗癌（促炎）免疫应答。在本申请中，我们将检验以下假设：靶向突变的Kras（驱动PDAC启动的第一个遗传改变）可以逆转与癌前病变发展和进展相关的进行性促癌耐受性极化。此外，我们将测试抑制性细胞反应受表观遗传控制的机制假设，并且靶向突变的Kras与改变一种或多种细胞类型的表型极性的药物一起导致这种前致癌进展，将导致肿瘤消退。我们将采用一种小鼠模型，该模型在发生浸润性癌症之前，通过遗传编程进展到恶性前期的三个阶段（胰腺上皮内肿瘤（PanIN）的级别增加）。在目的1中，我们将鉴定和表征在接种经基因工程改造以表达突变Kras（LM-Kras）的单核细胞增生李斯特菌（LM）细菌之前和之后由突变Kras启动的前致癌性炎性细胞群体的表型和功能。在目标2中，我们将对从小鼠和人PanIN分离的抑制性细胞与抗PanIN免疫群体进行遗传和表观遗传分析。在目标3中，我们将联合收割机将LM-Kras疫苗与DNA低甲基化药物5aza-dC（DAC）组合并测试协同抗肿瘤作用。这一应用具有重大的转化意义，将满足重要的临床需求-一级预防和早期治疗致命癌症。我们希望这些发现将推动一项“原则证明”临床试验，该试验在筛查诊所进行，这些诊所有发展PDAC的风险。

DESCRIPTION (provided by applicant): The immune system recognizes small protein differences between cancer cells and the normal tissue from which they derive. Immunotherapy (cancer vaccines and immune modulators) is an emerging modality that educates the immune system to recognize these differences. Most cancers are insidious in their initiation, and develop over 10 to 30 years making it difficult to know when best to vaccinate and for how long. With recent advances mapping the genetic and epigenetic changes in cancers, it is now possible to apply principles learned from virus-targeted vaccines to the development of immunotherapies targeting the pathways induced by early genetic changes (driver genes) that are critical to cancer initiation. Cancers develop through a long process involving interconnections between genetic, epigenetic, and inflammatory signaling pathways that are constantly changing within the target organ as cells transition from normal to pre-malignant, to invasive cancer. In pancreatic adenocarcinoma (PDAC), emerging evidence suggests that these early changes induce a tumor-tolerant (anti-inflammatory) immune environment that includes a desmoplastic fibroblastic component, as well as various types of immunosuppressive stromal cells that produce cytokines, which inhibit anticancer (pro-inflammatory) immune responses. In this application we will test the hypothesis that targeting mutated Kras, the first genetic alteration driving PDAC initiation, can reverse the progressive pro-carcinogenic tolerogenic polarization that is associated with premalignancy development and progression. Furthermore, we will test the mechanistic hypothesis that the suppressive cellular response is under epigenetic control, and that targeting mutated Kras together with agents that change the phenotypic polarity of one or more cell types responsible for this procarcinogenic progression, will lead to tumor regression. We will employ a mouse model genetically programmed to progress through three stages of premalignancy (pancreatic intraepithelial neoplasms (PanINs) of increasing grade) before developing invasive cancer. In Aim 1 we will identify and characterize the phenotype and function of procarcinogenic inflammatory cell populations that are initiated by mutated Kras before and after vaccination with Listeria monocytogenes (LM) bacteria genetically engineered to express mutated Kras (LM-Kras). In Aim 2 we will perform a genetic and epigenetic analysis of suppressive cell versus anti-PanIN immune populations isolated from mouse and human PanINs. In Aim 3 we will combine the LM-Kras vaccine with the DNA hypomethylating drug 5aza- dC (DAC) and test for a synergistic anti-tumor effect. This application has significant translational implications that will fulfill an important clinical need - primary prevention and ealy treatment of a deadly cancer. We expect that the findings will drive a "proof of principle" clinica trial in subjects followed in screening clinics who are at risk for developing PDAC.