Mice as Models to Study Receptor Tyrosine Kinase Funct.

以小鼠为模型研究受体酪氨酸激酶功能。

• 批准号: 7048302
• 负责人: GLENN T. MERLINO
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7048302
• 关键词: cancer risk; disease /disorder model; environment related neoplasm /cancer; enzyme activity; gene expression; genetic susceptibility; genetically modified animals; hepatocyte growth factor; laboratory mouse; melanoma; mitogen activated protein kinase; neoplasm /cancer genetics; neoplastic cell; neoplastic process; pediatric neoplasm /cancer; protein structure function; protein tyrosine kinase; rhabdomyosarcoma; transfection; ultraviolet radiation

The Molecular Genetics Section (MGS) seeks to elucidate the complex molecular/genetic program governing tumor genesis and progression through the development of genetically engineered mouse models of human cancer. A major goal is to identify candidate targets or pathways for both mechanistic enlightenment and future therapeutic utility. Our efforts in this regard are focused on two tumor types, cutaneous malignant melanoma (CMM) and the pediatric malignancy rhabdomyosarcoma (RMS).Exposure to UV radiation is a causal agent in the vast majority of CMM. Retrospective epidemiological data suggest that CMM is provoked by intense intermittent exposure to UV, particularly during childhood. We tested this hypothesis in mice in which expression of a transgene encoding the c-Met ligand, hepatocyte growth factor/scatter factor (HGF/SF), induced sporadic melanocytic tumors in aged animals. We discovered that a single neonatal dose of erythemal UV radiation was necessary and sufficient to induce cutaneous melanoma reminiscent of human CMM with high penetrance and relatively short latency (Noonan et al., Nature 413: 271-2, 2001). A critical role for the INK4a/ARF locus, widely regarded as a key melanoma suppressor in human patients, in our HGF/SF transgenic mouse model was confirmed by demonstrating that UV-induced melanoma was significantly accelerated on a genetic background deficient in Ink4a/Arf (Recio et al., Cancer Res. 62: 6724-30, 2002). These results strongly suggest that sunburn is a significant risk factor in kindreds harboring germline mutations in INK4a/ARF (Merlino and Noonan, Trends Mol. Med. 9: 102-8, 2003). There as been much controversy surrounding the relative risks associated with UVB versus UVA radiation. Recently, we used this HGF/SF transgenic mouse to show that UVB alone, but not UVA alone, is able to induce the full melanoma phenotype (DeFabo et al., Cancer Res. 64: 6372-6, 2004).The childhood malignancy RMS, accounting for 5 to 10% of all pediatric neoplasms and for more than 50% of pediatric soft tissue sarcomas, is thought to arise from imbalances in skeletal muscle cell proliferation and differentiation. However, molecular pathways associated with RMS remain largely unknown, due in part to the lack of an RMS-prone mouse model. In the course of studying genetic interactions between c-MET and the INK4a/ARF locus, we discovered that virtually all HGF/SF transgenic, Ink4a/Arf-deficient mutant mice rapidly succumbed to highly invasive RMS (Sharp et al., Nature Med. 8: 1276-80, 2002). Comparable molecular lesions in c-MET, pRB and p53 pathways have been individually described for human RMS. These data provide genetic evidence that c-MET and INK4a/ARF pathways represent critical and synergistic targets in RMS pathogenesis, and suggest a rational therapeutic combination to combat this pediatric cancer.Patients presenting with metastatic RMS continue to have a very poor clinical prognosis due in large part to our rudimentary knowledge of molecular events that dictate metastatic potential. We have generated numerous highly and poorly metastatic cell lines from the RMS tumors arising in our HGF/SF-transgenic, Ink4a/Arf-deficient mice, which are proving to be a valuable research tool for studying mechanisms associated with metastatic dissemination. cDNA microarray analysis of these cell lines identified a set of genes whose expression was significantly different between highly and poorly metastatic cells. Subsequent in vivo functional studies revealed that the actin filament-plasma membrane crosslinker Ezrin and the homeodomain-containing transcription factor Six1 had essential roles in determining the metastatic fate of RMS cells. Notably, EZRIN and SIX1 expression levels were also enhanced in human RMS tissue, significantly correlating with clinical stage. The identification of EZRIN and SIX1 as critical regulators of metastasis in RMS provides new mechanistic and perhaps therapeutic insight into this pediatric cancer.

分子遗传学部分（MGS）旨在通过发展遗传性的人类癌症的基因工程小鼠模型来阐明控制肿瘤起源和进展的复杂分子/遗传程序。一个主要目标是确定机械启蒙和未来治疗效用的候选目标或途径。我们在这方面的努力集中在两种肿瘤类型上，皮肤恶性黑色素瘤（CMM）和小儿恶性横纹肌肉瘤（RMS）。暴露于紫外线辐射是绝大多数CMM的原因。回顾性的流行病学数据表明，CMM是由于强烈的间歇性暴露于紫外线而引起的，尤其是在儿童时期。我们在小鼠中检验了这一假设，在小鼠中，编码C-MET配体，肝细胞生长因子/散射因子（HGF/SF）的转基因的表达诱导了零星的近代动物中的零星黑素细胞肿瘤。我们发现，单一的新生儿剂量的红斑紫外线辐射是必要的，足以诱导皮肤黑色素瘤，让人联想到人类CMM具有高渗透率和相对较短的潜伏期（Noonan等，Nature 413：271-2，2001）。在我们的HGF/SF转基因小鼠模型中，广泛认为是Ink4a/ARF基因座的关键作用，被广泛认为是人类患者的关键黑色素瘤抑制剂，这证明了紫外线诱导的黑色素瘤在Ink4a/arf中的遗传背景不足显着加速了（Recio等，Recio等，Recio et al。这些结果强烈表明，晒伤是藏有ink4a/arf种系突变（Merlino and Noonan，TrandsMol。Mol。9：102-8，2003）中的生殖线突变的重要危险因素。与UVB与UVA辐射相关的相对风险存在很多争议。 Recently, we used this HGF/SF transgenic mouse to show that UVB alone, but not UVA alone, is able to induce the full melanoma phenotype (DeFabo et al., Cancer Res. 64: 6372-6, 2004).The childhood malignancy RMS, accounting for 5 to 10% of all pediatric neoplasms and for more than 50% of pediatric soft tissue sarcomas, is thought to arise来自骨骼肌细胞增殖和分化的失衡。但是，与RMS相关的分子途径在很大程度上是未知的，部分原因是缺乏易RMS的小鼠模型。在研究C-MET与INK4A/ARF基因座之间的遗传相互作用的过程中，我们发现几乎所有HGF/SF转基因，Ink4a/ARF缺乏的突变体小鼠迅速屈服于高度侵入性的RMS（Sharp等人，自然中等，8：1276-80，2002）。 C-MET，PRB和P53途径中的可比较分子病变已针对人RMS进行了单独描述。这些数据提供了遗传学证据，表明C-MET和INK4A/ARF途径代表RMS发病机理中的关键和协同靶标，并提出了一种合理的治疗组合来对抗这种儿科癌症。具有转移性RMS的患者仍然具有很差的临床预后，这在我们对我们对分子的领域的临床知识中很大一部分，这是我们对分子的潜在潜在的。我们已经从HGF/SF-转基因，Ink4a/ARF缺陷小鼠中产生的RMS肿瘤产生了许多高度和差的转移性细胞系，这些小鼠被证明是研究与转移性传播相关的机制的有价值的研究工具。这些细胞系的cDNA微阵列分析鉴定了一组基因，其表达在高度和较差的转移细胞之间显着差异。随后的体内功能研究表明，肌动蛋白丝膜膜交联Ezrin和含同源域的转录因子Six1在确定RMS细胞的转移性命运方面具有重要作用。值得注意的是，在人RMS组织中，Ezrin和Six1表达水平也得到了提高，与临床阶段显着相关。 Ezrin和Six1作为RMS转移的关键调节剂的鉴定为这种儿科癌症提供了新的机械机械和治疗性洞察力。