Identifying Events and Genetic Regulators of Melanoma Progression

描述（由申请人提供）：本提案的目标是研究黑色素瘤形成的事件和遗传缺陷。黑色素瘤是最具侵袭性和致命性的皮肤癌。大多数良性痣和黑素瘤都有激活BRAF丝氨酸/苏氨酸激酶的突变，这表明BRAF激活是肿瘤发生中一个重要但不充分的步骤。P53通路的改变也与黑色素瘤的形成有关。虽然许多功能都归因于BRAF和p53，但对于这些功能中哪些在将正常黑色素细胞转化为黑色素瘤细胞中起重要作用却知之甚少。此外，导致这一过程的其他遗传缺陷尚未确定。表达人类致癌基因BRAF和p53突变体的斑马鱼菌株已经被创造出来。这些菌株可靠地发展为组织病理学上与人类相似的黑色素瘤。初步结果表明，这些突变体中的双核、多倍体黑色素细胞可能引起肿瘤。在Aim 1中，将检查黑色素瘤形成的事件。斑马鱼的转基因方法和哺乳动物细胞培养的长期成像将用于确定BRAF引起双核的机制。细胞分选结合移植将用于确定双核细胞是否会导致黑色素瘤。在第二阶段，将识别和描述导致黑色素瘤形成的遗传缺陷。在初步研究中，Kit受体酪氨酸激酶被确定为黑色素瘤发病和侵袭的抑制因子。试剂盒抑制黑色素瘤所需的活性将被评估。为了确定额外的黑色素瘤遗传缺陷，阵列比较基因组杂交（aCGH）将用于表征这些肿瘤中复发性染色体的获得和损失。来自人类和斑马鱼黑色素瘤的aCGH数据将用于识别候选癌基因，这些癌基因将在一种新的、高通量的检测方法中进行测试，以确定对黑色素瘤形成的贡献。这些研究可以确定疾病的诊断和预后指标以及癌症治疗的治疗靶点。

DESCRIPTION (provided by applicant): The goals of this proposal are to examine the events and genetic defects that underlie melanoma formation. Melanoma is the most aggressive and lethal form of skin cancer. Most benign nevi and melanomas have mutations activating the BRAF serine/threonine kinase, suggesting that BRAF activation is an important but insufficient step in tumorigenesis. p53 pathway alterations are also implicated in melanoma formation. While many functions have been ascribed to BRAF and p53, little is known about which if any of these functions is important in transforming normal melanocytes into melanoma cells. Furthermore, additional genetic defects that contribute this process have yet to be defined. Zebrafish strains that express human oncogenic BRAF and are mutant for p53 have been created. These strains reliably develop melanomas that are histopathologically similar to those in humans. Preliminary results indicate that binucleate, polyploid melanocytes in these mutants may give rise to tumors. In Aim 1, the events of melanoma formation will be examined. Transgenic approaches in zebrafish and long-term imaging of mammalian cells in culture will be used to determine the mechanism by which BRAF causes binuclearity. Cell sorting coupled with transplantation will be employed to determine whether binucleate cells can give rise to melanomas. In Aim 2, genetic defects that contribute to melanoma formation will be identified and characterized. In preliminary studies, the Kit receptor tyrosine kinase was identified as a suppressor of melanoma onset and invasion. Activities of Kit required for its melanoma suppression will be assessed. To identify additional melanoma genetic defects, array comparative genomic hybridization (aCGH) will be used to characterize recurrent chromosomal gains and losses in these tumors. aCGH data from human and zebrafish melanomas will be used to identify candidate oncogenes that will be tested in a novel, high-throughput assay for contribution to melanoma formation. These studies may identify diagnostic and prognostic indicators of disease as well as therapeutic targets for cancer treatment.