RETINOID INDUCED TUMOR DIFFERENTIATION AND THE CELL CYCL

描述（申请人描述）： 本提案的目的是确定RA诱导的 肿瘤分化的细胞周期的变化，导致G1-S停滞。 阐明肿瘤分化的起始如何与细胞偶联 自行车机械应该导致更大的实现的潜力， 成熟的癌症治疗。 人类生殖细胞癌 （畸胎瘤）细胞系，NT 2/D1，在RA诱导的G1期阻滞 神经元分化 初步数据表明，在应对RA， NT 2/D1细胞表现出细胞周期蛋白D1表达的进行性下降， 与细胞增殖的下降相平行。 表型成熟和 此后发生G1期细胞积累。 一个抗RA的克隆体 NT 2/D1-R1，不表达类视色素受体-γ（RAR γ）， 在G1期不积累，持续过表达cyclin D1和p53。 外源性RAR γ表达逆转了RA抗性， RA介导的细胞周期蛋白D1下降。 本建议旨在了解RA如何 这些信号细胞周期的变化导致生长抑制。 第一 特定的目的确定RA实现G1期阻滞的机制， 比较G1-S的已知介质的生化活性和表达 RA敏感和耐药NT 2/D1细胞的进展。 第二特定 目的是确定RA诱导的细胞周期变化是否是介导 诱导生长抑制和成熟，通过研究RA的敏感性， 细胞工程过表达细胞周期蛋白D1，p53和其他突出显示的细胞 循环组件。 第三个具体目标探讨了RAR的作用， 在细胞周期中通过单独的信号传导RA诱导的变化， 在RA敏感和耐药细胞中过度表达特异性类维生素A受体 NT 2/D1细胞。 RAR γ在肿瘤分化中的直接作用是 在具体目标4中通过工程线路来解决， 显性负性RAR γ构建体。 这项研究解决了 诱导肿瘤生长抑制和分化的机制 细胞 这些具体目标的成功实现应有助于 合理使用维甲酸类药物治疗和预防癌症。

DESCRIPTION (Applicant's Description): The objective of this proposal is to identify mechanisms linking RA-induced tumor differentiation to changes in the cell cycle leading to G1-S arrest. Elucidating how initiation of tumor differentiation is coupled to the cell cycle machinery should lead to a greater fulfillment of the potential of maturation-based cancer therapy. The human germ cell cancer (teratocarcinoma) cell line, NT2/D1, arrests in G1 during RA-induced neuronal differentiation. Preliminary data indicate in response to RA, NT2/D1 cells show a progressive d e c l ine in cyclin D1 expression that parallels a decline in cell proliferation. Phenotypic maturation and accumulation of cells in G1 occur thereafter. An RA-resistant clone, NT2/D1-R1, shown not to express the retinoid receptor-gamma (RARgamma), did not accumulate in G1 and persistently overexpressed cyclin D1 and p53. Exogenous RARgamma expression reversed RA resistance and restored RA-mediated decline of cyclin D1. This proposal is designed to learn how RA signals those cell cycle changes causing growth suppression. The first specific aim identifies the mechanisms by which RA achieves G1 arrest by comparing the biochemical activity and expression of known mediators of G1-S progression in RA-sensitive and resistant NT2/D1 cells. The second specific aim determines whether RA-induced cell cycle changes are causal in mediating induced growth suppression and maturation by studying the RA sensitivity of cells engineered to overexpress cyclin D1, p53 and other highlighted cell cycle components. The third specific aim explores the role of RARs in signaling RA-induced changes in the cell cycle by individually over-expressing specific retinoid receptors in RA-sensitive and resistant NT2/D1 cells. The direct role of RARgamma in tumor differentiation is addressed in Specific Aim 4 by engineering lines to express a dominant-negative RARgamma construct. This research addresses the mechanisms of induced growth suppression and differentiation of human tumor cells. The successful completion of these specific aims should aid in the rational use of retinoids in cancer therapy and prevention.