Genomic-wide Kinase Sequencing of Pediatric Brain Tumors

描述(申请人提供)：儿童神经外胚层起源的癌症是儿童最常见的实体肿瘤，现在是儿童癌症相关死亡的最常见原因。这笔赠款的目标是确定两种最常见的儿童中枢神经系统癌症--恶性髓母细胞瘤和低级别星形细胞瘤--的可用药靶点。这两种肿瘤都没有表现出成人恶性星形细胞瘤的特征--大体染色体不稳定。这两种肿瘤通常都是野生型，因为成年中枢神经系统癌症中最常见的肿瘤抑制基因突变--P53、Rb和PTEN。另一方面，在这些肿瘤中，上调的激酶活性与不良的预后或增加的转移潜能有关。这项赠款的假设是，髓母细胞瘤和低级别星形细胞瘤的恶性表型反映了每种肿瘤类型特有的单一蛋白激酶(或少量蛋白激酶)内的功能获得突变。最近对恶性黑色素瘤遗传学的洞察表明，这一假设是合理的。我们已经组建了一个三方团队，1)儿科肿瘤学/神经病理学，2)分子生物学/生物信息学，3)信号转导/药物发现，使假说可验证，我们的目标可以实现。我们的研究计划有三个目标：(1)连续三年每年从至少15例髓母细胞瘤和15例低级别星形细胞瘤中提取DNA进行突变分析。(2)确定参与致癌信号通路的所有酪氨酸激酶和所有丝氨酸/苏氨酸和脂蛋白激酶的突变。为此，我们将对大约4000个外显子进行测序，覆盖酪氨酸激酶和所有致癌丝氨酸/苏氨酸激酶的整个编码序列，以及剩余的丝氨酸/苏氨酸激酶和1型PI3激酶的关键部分，(3)表征突变的激酶的生化活性和生物活性。突变的激酶将接受一系列分析测试，以确定突变是否会在体外或细胞内增加激酶的比活性。最后，我们将确定突变是否增加了该激酶的转化潜力。这项研究将为患有脑癌的儿童带来新一代选择性疗法。由于儿童癌症在更大的背景下通常是“信息性的”，这些药物很可能会被用于更常见的成人癌症。

DESCRIPTION (provided by applicant): Pediatric cancers of neural ectodermal origin are the most common solid tumor in children and are now the most common cause of cancer-related death in children. The goal of this grant is to define drugable targets for two of the most common pediatric cancers of the central nervous system - malignant medulloblastoma and low-grade astrocytoma. Neither of these tumors exhibits gross chromosomal instability that characterizes malignant astrocytomas in adults. Both tumors are generally wild type for the tumor suppressor genes most commonly mutated in adult CNS cancers - p53, RB and PTEN. On the other hand, upregulated kinase activity has been associated with poor outcome or increased metastatic potential in these tumors. The hypothesis of this grant is that the malignant phenotype for medulloblastoma and also for low-grade astrocytoma reflects a gain-of-function mutation within a single protein kinase (or a small number of kinases) unique to each tumor type. Recent insights into the genetics of malignant melanoma suggest that this hypothesis is reasonable. We have assembled a tripartite team in 1) Pediatric Oncology/Neuro Pathology, 2) Molecular Biology/Bioinformatics and 3) Signal Transduction/Drug Discovery that makes the hypothesis testable and our goal achievable. Our study plan has three aims: (1) to isolate DNA for mutation analysis from at least 15 medulloblastoma and 15 low-grade astrocytomas a year for three years. (2) to identify mutations in all tyrosine kinases and all serine/threonine and lipid kinases involved in oncogenic signaling pathways. Towards this end, we will sequence roughly 4000 exons, covering the entire coding sequences of tyrosine kinases and of all oncogenic serine/threonine kinases as well as key portions of the remaining serine/threonine kinases and type 1 PI3 kinases, (3) to characterize the biochemical activity and biological activity of the mutant kinases. Mutant kinases will be subjected to a battery of analytical tests to see if the mutation increases the specific activity of the kinase in vitro or in cells. Finally, we will determine if the mutation increases the transformation potential of the kinase. The research will lead to a new generation of selective therapeutics for children with brain cancer. Since cancers of children are often "informative" in a larger context, it is likely that these medicines will find use for more frequent adult cancers.