P53 survival target DDR1 kinase in DNA damage response and carcinogenesis

 描述(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，它调节与细胞周期停滞和凋亡相关的基因的表达。我们先前发现DDR1激酶是P53的直接靶基因。我们发现，与其他典型的P53靶基因不同，在含有WT P53的癌细胞中，DDR1K通过抵消P53介导的凋亡来促进细胞存活。DDR1最初是在人类恶性肿瘤中表达的酪氨酸激酶蛋白的筛查中发现的，也是在各种人类癌症中发现的几种主要激活的酪氨酸激酶之一。从最近的功能癌症基因组学研究(Norvatis/BRoad Consortium)中，DDR1被扩增，并在许多类型的人类恶性肿瘤中发生突变，包括上皮癌和淋巴瘤。然而，该受体促进肿瘤发生的具体分子机制(S)仍不完全清楚。我们的初步数据显示，人类癌细胞系中的几个DDR1突变似乎促进了DDR1的结构性激活，并对广泛的激酶抑制剂如Dastinib和Iressa产生了耐药性。我们的研究清楚地证明了DDR1通路在维持癌细胞存活、增殖和迁移/侵袭方面的重要作用。随后，我们确定EMT调节剂是DDR1的下游途径。利用体内和体外综合的生化、治疗和遗传学方法，这一应用的总体目标是阐明DDR1改变在响应遗传毒性应激时促进肿瘤发生和促进生存的特定分子机制。我们推测，虽然依赖于p53的DDR1上调对遗传毒性应激/DNA损伤具有保护作用，但DDR1突变是一组癌细胞中重要的致癌事件，有助于细胞存活并在癌细胞的化疗耐药中发挥作用。进一步了解DDR1介导的体外和体内生存/保护反应背后的这一未知途径，有望最终转化为治疗肿瘤的益处。为了验证上述假设，我们提出了以下三个具体目标：第一，研究体内和体外基因组变化导致的结构性DDR1受体激酶激活的功能意义和致癌潜力；第二，检测DDR1缺失是否导致体内肿瘤的发生抑制和对遗传毒性应激的保护性反应；这一目的将在一个遗传性小鼠肿瘤模型中探讨DDR1缺失如何促进乳腺肿瘤的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.