Identifying Events and Genetic Regulators of Melanoma Progression

描述（由申请人提供）：本提案的目的是检查黑色素瘤形成的事件和遗传缺陷。黑色素瘤是最具侵略性和致命性的皮肤癌。大多数良性痣和黑色素瘤具有激活BRAF丝氨酸/苏氨酸激酶的突变，表明BRAF激活是肿瘤发生中重要但不充分的步骤。p53途径的改变也与黑色素瘤的形成有关。虽然BRAF和p53具有许多功能，但很少有人知道这些功能中的任何一种在将正常黑素细胞转化为黑色素瘤细胞中是否重要。此外，导致这一过程的其他遗传缺陷尚未确定。已经产生了表达人致癌BRAF并且是p53突变体的斑马鱼品系。这些菌株可靠地发展出与人类组织病理学相似的黑色素瘤。初步结果表明，双核，多倍体黑素细胞在这些突变体可能会引起肿瘤。在目的1中，将检查黑色素瘤形成事件。将使用斑马鱼的转基因方法和培养中哺乳动物细胞的长期成像来确定BRAF导致双核的机制。将采用细胞分选结合移植来确定双核细胞是否可以引起黑色素瘤。在目标2中，将鉴定和表征有助于黑色素瘤形成的遗传缺陷。在初步研究中，Kit受体酪氨酸激酶被鉴定为黑色素瘤发作和侵袭的抑制剂。将评估Kit抑制黑色素瘤所需的活性。为了确定其他黑色素瘤遗传缺陷，将使用阵列比较基因组杂交（aCGH）来表征这些肿瘤中的复发性染色体获得和丢失。来自人类和斑马鱼黑色素瘤的aCGH数据将用于鉴定候选癌基因，这些癌基因将在一种新的高通量测定中进行测试，以确定其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.