(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和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）是一种新兴的模式，教育免疫系统认识到这些差异。大多数癌症在开始时是潜伏的，并且在10到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。随着绘制癌症的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开发针对早期遗传变化（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。癌症的发展是一个长期的过程，涉及基因、表观遗传和炎症信号通路之间的相互联系，随着细胞从正常到恶性前病变，再到侵袭性癌症，这些信号通路在靶器官内不断变化。在胰腺腺癌（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，包括促结缔组织增生纤维母细胞成分，以及产生抑制抗癌（促炎）免疫反应的各种类型的免疫抑制基质细胞。在这个应用中，我们将测试一个假设，即靶向突变的Kras，第一个驱动PDAC启动的基因改变，可以逆转与恶性肿瘤前发展和进展相关的渐进的致癌前耐受性极化。此外，我们将测试抑制细胞反应受表观遗传控制的机制假设，以及靶向突变的Kras和改变导致这种前癌进展的一种或多种细胞类型的表型极性的药物将导致肿瘤消退。我们将采用遗传编程的小鼠模型，在发展为浸润性癌症之前经历三个阶段的恶性前病变（胰腺上皮内肿瘤（PanINs）的等级增加）。在Aim 1中，我们将鉴定和表征在接种单核增生李斯特菌（LM）细菌基因工程表达突变Kras （LM-Kras）前后由突变Kras启动的癌前炎性细胞群的表型和功能。在目标2中，我们将进行从小鼠和人类PanINs分离的抑制细胞与抗panin免疫群体的遗传和表观遗传分析。在Aim 3中，我们将LM-Kras疫苗与DNA低甲基化药物5aza- dC （DAC）联合使用，并测试其协同抗肿瘤效果。这一应用具有重要的转化意义，将满足一个重要的临床需求-一种致命癌症的初级预防和早期治疗。我们期望这些发现将推动临床试验的“原理证明”，在筛选有患PDAC风险的诊所进行。

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.