Role of extracellular matrix proteins and tumor stroma in DNA repair and cancer progression

项目摘要 胰腺导管腺癌（PDA）是美国第四大致死性癌症，5年生存率为 只有~ 10%。PDA的主要治疗方法是化疗，然而，大多数肿瘤在治疗过程中会迅速死亡。 产生抗药性。因此，迫切需要了解是什么推动了 PDA的耐药性，并制定更好的治疗策略。耐药性的一个促成因素是 PDA是肿瘤微环境，其特征是基质丰富，细胞外基质丰富， (ECM)蛋白质，最常由癌症相关的成纤维细胞分泌。基质和分泌的ECM 蛋白质可以诱导对化学疗法的抵抗，化学疗法通过破坏DNA起作用。的一种方式 基质诱导化疗抗性的方法是增强DNA修复。我们的数据显示癌症- 相关的成纤维细胞分泌的ECM蛋白刺激PDA肿瘤细胞的DNA修复，使其更 抵抗治疗。本申请的总体目标是研究 肿瘤微环境，特别是分泌的基质和ECM蛋白，刺激DNA修复。我们 中心假设是我们已经鉴定的候选蛋白，称为N-Myc-下游调节基因， 1（NDRG 1），将信号从ECM接触传递到DNA修复机器，我们的初步数据 支持这一假设。为了进一步验证这一假设，我们提出了以下三个具体目标：1） 确定分泌的ECM蛋白导致NDRG 1活化的详细信号传导事件; 2） 确定NDRG 1调节DNA修复的机制;以及3）评估NDRG 1- 在患者来源的类器官和胰腺癌体内模型中增强化疗的途径抑制 癌在我们看来，这里提出的研究是创新的，因为对化学抗性的研究 和DNA修复尚未在粘附信号传导和基质微环境的背景下进行研究， 我们在这里研究的蛋白质NDRG 1与DNA修复有关。因此，成功 这项工作的完成将导致对肿瘤-间质如何交叉的更完整的机械理解， Talk和成纤维细胞分泌基质蛋白调节DNA修复，以及NDRG 1蛋白如何促进DNA修复 修复和治疗阻力。这些贡献预计将是重要的，因为它们揭示了新的 DNA修复生物学是由细胞外基质环境调节的最致命的，基质丰富的 和耐药癌症，并将使我们能够测试是否针对这一信号通路将增强 化疗疗效

PROJECT SUMMARY Pancreatic ductal adenocarcinoma (PDA) is the fourth lethal cancer in the U.S. with a 5-year survival rate of only ~10%. The mainstay of therapy in PDA is chemotherapy, however, the majority of the tumors rapidly develop treatment resistance. Therefore, a critical need exists to understand what drives the emergence of drug resistance in PDA, and to develop better treatment strategies. One contributing factor to drug resistance in PDA is the tumor microenvironment, which is characterized by abundant stroma, rich in extracellular matrix (ECM) proteins, most frequently secreted by cancer-associated fibroblasts. The stroma and the secreted ECM proteins can induce resistance towards chemotherapies, which work by inflicting DNA damage. One way for the stroma to induce chemo-resistance would be by enhancing DNA repair. Our data show that the cancer- associated fibroblast-secreted ECM proteins stimulate DNA repair in PDA tumor cells, making them more resistant to treatments. The overall objective of this application is to investigate the mechanistic basis by which the tumor microenvironment, and particularly secreted stromal and ECM proteins, stimulate DNA repair. Our central hypothesis is that the candidate protein we have identified, called N-Myc-Downstream Regulated Gene 1 (NDRG1), conveys signals from the ECM contact to the DNA repair machinery, and our preliminary data support this hypothesis. To test this hypothesis further, we propose the following three specific aims: 1) to determine the detailed signaling events by which secreted ECM proteins lead to NDRG1 activation; 2) to determine the mechanism by which NDRG1 regulates DNA repair; and 3) to assess the efficacy of NDRG1- pathway inhibition in enhancing chemotherapy in patient-derived organoids and in vivo models of pancreatic cancer. The research proposed here is innovative, in our opinion, because the research on chemoresistance and DNA repair has not been studied in the context of adhesion signaling and stromal microenvironment, nor has the protein we propose to study here, NDRG1, been linked to DNA repair. Therefore, successful completion of this work would lead to a more complete mechanistic understanding on how tumor-stroma cross- talk and fibroblast-secreted matrix proteins regulate DNA repair, and how NDRG1 protein contributes to DNA repair and treatment resistance. These contributions are expected to be significant because they reveal novel DNA repair biology that is regulated by extracellular matrix environment in one of the most lethal, stroma rich and drug resistant cancers, and will allow us to test whether targeting this signaling pathway will enhance chemotherapy efficacy.