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

描述(申请人提供)：免疫系统识别癌细胞和它们衍生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，它教育免疫系统认识到这些差异。大多数癌症在发病初期都是潜伏的，并在10到30年内发展，因此很难知道什么时候接种疫苗最好，接种多久。随着绘制癌症基因和表观遗传变化图谱的最新进展，现在有可能将从病毒靶向疫苗中学到的原理应用于开发针对早期基因变化(驱动基因)诱导的途径的免疫疗法，这些途径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，随着细胞从正常到癌前病变再到侵袭性癌症的转变，这些信号通路在靶器官内不断变化。在胰腺癌(PDAC)中，新出现的证据表明，这些早期变化诱导了肿瘤耐受(抗炎)免疫环境，其中包括促结缔组织成纤维细胞成分，以及各种类型的免疫抑制基质细胞，它们产生细胞因子，抑制抗癌(促炎)免疫反应。在这项应用中，我们将测试以下假设：靶向突变的Kras，驱动PDAC启动的第一个基因改变，可以逆转与癌前病变发展和进展相关的进行性致癌耐受极化。此外，我们将测试机制假设，即抑制性细胞反应受表观遗传控制，靶向突变的Kras与改变导致这种癌前进展的一种或多种细胞类型的表型极性的药物一起，将导致肿瘤退化。我们将使用一个小鼠模型，通过基因编程，在发展为浸润性癌症之前，经历三个癌前阶段(胰腺上皮内肿瘤(Panins)，级别不断增加)。在目标1中，我们将鉴定和表征突变的Kras在接种表达突变的Kras的基因工程菌(Lm-Kras)前后由突变的Kras启动的致癌前炎症细胞群的表型和功能。在目标2中，我们将对从小鼠和人Panins中分离的抑制性细胞和抗Panin免疫群体进行遗传和表观遗传学分析。在目标3中，我们将把LM-Kras疫苗与DNA低甲基化药物5aza-DC(DAC)结合，并测试其协同抗肿瘤效果。这一应用具有重大的翻译意义，将满足一项重要的临床需求--致命癌症的初级预防和早期治疗。我们希望这些发现将推动一项“原则证明”临床试验，在筛查有患PDAC风险的诊所的受试者中进行。

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.