P53 survival target DDR1 kinase in DNA damage response and carcinogenesis

 描述（由申请人提供）：基因毒性/DNA损伤应激反应的中心协调者是肿瘤抑制因子p53，其调节参与细胞周期阻滞和细胞凋亡的基因的表达。我们以前确定DDR 1激酶作为p53的直接靶基因。我们发现，与其他典型的p53靶基因不同，DDR 1激酶通过抵消含有WT p53的癌细胞中p53介导的凋亡来促进细胞存活。DDR 1最初是在筛选人类恶性肿瘤中表达的酪氨酸激酶蛋白质中鉴定的，并且也被发现是多种人类癌症中的几种主要活化酪氨酸激酶之一。根据最近的功能性癌症基因组学研究（Norvatis/Broad Consortium），DDR 1在许多类型的人类恶性肿瘤（包括上皮癌和淋巴瘤）中被扩增和突变。然而，这种受体可能有助于肿瘤发生的特定分子机制仍不完全清楚。我们的初步数据显示，人类癌细胞系中的几种DDR 1突变似乎促进DDR 1的组成性激活，并对广泛的激酶抑制剂如达司替尼和易瑞沙产生耐药性。我们的研究清楚地证明了DDR 1通路在维持癌细胞存活、增殖和迁移/侵袭中的重要作用。随后，我们确定了EMT调节剂作为DDR 1的下游途径。本申请的总体目标是使用体外和体内的综合生物化学、治疗和遗传方法来阐明DDR 1改变响应于遗传毒性应激而促进肿瘤发生和促存活的特定分子机制。我们假设，虽然p53依赖性的DDR 1上调对基因毒性应激/DNA损伤起保护作用，但DDR 1突变是癌细胞亚群中重要的致癌事件，有助于细胞存活并在癌细胞的化疗耐药性中起作用。进一步了解这种未探索的途径，在体外和体内的DDR 1介导的促生存/保护反应，预计最终转化为治疗肿瘤的治疗效益。为了验证上述假设，我们提出了以下三个具体目标：首先，在体外和体内研究基因组改变导致的组成型DDR 1受体激酶激活的功能意义和致癌潜力，其次，在体内研究DDR 1缺陷是否导致肿瘤发生的抑制和对基因毒性应激的保护性反应;这一目标将研究DDR 1缺陷如何在遗传小鼠肿瘤模型中促进乳腺肿瘤进展和遗传毒性应激反应。

 DESCRIPTION (provided by applicant): The central coordinator of the genotoxic/DNA damage stress response is tumor suppressor p53, which regulates the expression of genes involved in cell cycle arrest and apoptosis. We previously identified DDR1 kinase as a direct target gene of p53. We found that, unlike other typical p53 target genes, DDR1 kinase promotes cell survival by offsetting p53-mediated apoptosis in cancer cells containing WT p53. DDR1 was originally identified in a screen for tyrosine kinase proteins expressed in human malignancies and also found as one of several major activated tyrosine kinases in a variety of human cancers. From recent functional cancer genomics efforts (Norvatis/Broad Consortium), DDR1 is amplified, and mutated in many types human malignancies, including epithelial cancers and lymphomas. However, the specific molecular mechanism(s) by which this receptor may contribute to oncogenesis remains incompletely understood. Our preliminary data show that several DDR1 mutations in human cancer cell lines appear to promote constitutively activation of DDR1 and exert resistance to broad kinase inhibitors such as dastinib and iressa. Our studies clearly demonstrate the essential role of the DDR1 pathway in maintaining cancer cell survival, proliferation and migration/invasion. Subsequently, we have identified EMT regulators as a downstream pathway of DDR1. Using integrated biochemical, therapeutic and genetic approaches in vitro and in vivo, the overall goal of this application is to elucidate the specific molecular mechanism by which DDR1 alterations contribute to tumorigenesis and pro-survival in response to genotoxic stress. We hypothesize that while p53-dependent up-regulation of DDR1 plays a protective role against genotoxic stress/DNA damage, DDR1 mutations are important oncogenic events in a subset of cancer cells that contribute to cell survival and play a role in chemo-resistance in cancer cells. Further understanding of this unexplored pathway underlying DDR1-mediated prosurvival/protective response in vitro and in vivo is expected to eventually translate into therapeutic benefits for the treatment of tumors. To test the above hypotheses, we propose the following three specific aims: firstly to investigate the functional significance and oncogenic potential of constitutive DDR1 receptor kinase activation resulting from genomic alterations in vitro and in vivo, and secondly to examine whether DDR1-deficiency results in the suppression of tumorigenesis and protective response to genotoxic stress in vivo; this aim will investigate how DDR1- deficiency contributes to mammary tumor progression and to genotoxic stress response in a genetic mouse tumor model.