RARbeta in Melanoma: Epigenetic Regulation by Nutrients

描述（由申请人提供）：黑色素瘤的发病率在美国人口中迅速增加。文献中的数据表明，表观遗传变化有助于黑色素瘤的发生和进展。我们实验室的数据表明，视黄酸核受体rar - β 2是一种肿瘤抑制基因，它的沉默导致了视黄酸抑制黑色素瘤细胞生长的能力丧失。在这项探索性研究中，一组具有营养和癌症专业知识的科学家；DNA甲基化;研究rar - β 2启动子DNA甲基化，以及rar - β 2启动子相关的组蛋白修饰和染色质结构变化，在正常的人类黑色素细胞和人类黑色素瘤细胞中rar - β 2表达降低。随后，我们将测量EGCG、染料木素和丁酸盐单独或联合改变人类黑色素瘤细胞中这些表观遗传修饰的能力。选择这些膳食成分是因为它们有能力改变癌细胞的表观遗传变化。它们也被证明可以抑制某些人类黑色素瘤细胞系的生长。如果这些饮食成分逆转黑色素瘤细胞系的表观遗传变化，我们将确定这是否会导致rar - β 2基因的重新表达和维甲酸对该基因诱导的恢复。最后，我们将测量EGCG、染料木素和丁酸盐单独或联合抑制人类黑色素瘤细胞系锚定依赖/独立生长和基底膜入侵的能力。这些表型改变依赖于营养物质引起RARbeta2再表达的能力，将通过使用siRNA抑制RAR-beta2的再表达来测试。这些营养物质改变rar - β 2 siRNA处理细胞中黑色素瘤表型的能力的丧失将证明rar - β 2重新表达的必要性。这项探索性研究将为黑色素瘤细胞的营养表观遗传机制提供新的和潜在的重要数据。根据获得的结果，这项调查可以转化为黑色素瘤动物模型的营养研究。

DESCRIPTION (provided by applicant): The incidence of melanoma is rapdily increasing in the US population. Data in the literature indicate that epigenetic changes contribute to the development and progression of melanoma. Our laboratory has generated data that suggests the retinoic acid nulcear receptor, RAR-beta2, acts a a tumor suppressor gene and that its silencing contributes to the loss of retinoic acid's ability to inhibit growth of melanoma cells. In this exploratory study, a team of scientsits with expertise in nutrition and cancer; DNA methylation; and dhromatin structure will examine RAR-beta2 promoter DNA methylation, and RAR-beta2 promoter- associated changes in histone modification and chromatin structure in normal human melanocytes and human melanoma cells having decreased expression of RAR-beta2.. Subsequently, we will measure the ability of EGCG, genistein and butyrate, alone or in combination, to alter these epigenetic modifications in the human melanoma cells. These dietary components were chosen for their reported ability to modify epigenetic changes in cancer cells. They also have been shown to inhibit the growth of some human melanoma cell lines. If these dietary constituents reverse epigenetic changes in our melanoma cell lines, we will determine if this results in the reexpression of the RAR-beta2 gene and restoration of retinoic acid induction of this gene. Lastly, we will measure the ability of EGCG, genistein and butyrate, alone or in combination to inhibit anchorage-dependent/independent growth and basement membrane invasion in our human melanoma cell lines. The dependency of these phenotypic alterations, on the ability of nutrients to cause reexpression of RARbeta2 will be tested by using siRNA to inhibit reexpression of RAR-beta2. Loss of the ability of these nutrients to alter the melanoma phenotpe in RAR-beta2 siRNA treated cells would demonstrate the requirement for RAR-beta2 reexpression. This exploratory study will provide new and potentially important data on nutrient epigenetic mechanisms in melanoma cells. Depending on results obtained, this investigation can be translated into nutritional studies with animal models of melanoma.