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

项目总结 胰腺导管腺癌(PDA)是美国第四大致命性癌症，5年生存率为 只有10%左右。动脉导管未闭的主要治疗方法是化疗，但大多数肿瘤进展迅速 产生治疗抵抗力。因此，迫切需要了解是什么推动了 对PDA的耐药性进行评估，并制定更好的治疗策略。导致抗药性的一个因素 PDA中的肿瘤微环境以丰富的间质、丰富的细胞外基质为特征 (ECM)蛋白质，最常由癌症相关的成纤维细胞分泌。基质和分泌的细胞外基质 蛋白质可以诱导对化疗产生耐药性，化疗是通过造成DNA损伤来实现的。一种方法是 诱导化疗耐药的基质可能是通过促进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，使它们 对治疗产生抗药性。这个应用程序的总体目标是研究其机制基础 肿瘤微环境，特别是分泌的间质和细胞外基质蛋白，刺激DNA修复。我们的 中心假设是我们已经确定的候选蛋白，称为N-Myc-下游调节基因 1(NDRG1)，将信号从ECM触点传递到DNA修复机制，以及我们的初步数据 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NDRG1激活的详细信号事件；2) 确定NDRG1调节DNA修复的机制；以及3)评估NDRG1的疗效- 在患者来源的有机化合物和体内胰腺模型中抑制通路在促进化疗中的作用 癌症。在我们看来，这里提出的研究是创新的，因为对化疗耐药性的研究 而DNA修复还没有在黏附信号和基质微环境的背景下进行研究，也没有 我们打算在这里研究的蛋白质NDRG1是否与DNA修复有关。因此，成功了 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制的理解。 Talk和成纤维细胞分泌的基质蛋白调节DNA修复，以及NDRG1蛋白如何参与DNA 修复和治疗耐药。这些贡献预计将是重大的，因为它们揭示了新的 由细胞外基质环境调节的DNA修复生物学在最致命、基质丰富的 以及耐药癌症，并将使我们能够测试靶向这一信号通路是否会增强 化疗效果。

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.