RETINOID INDUCED TUMOR DIFFERENTIATION AND THE CELL CYCL

描述(申请人的描述)： 该提案的目的是确定与RA诱导的 肿瘤分化到细胞周期改变导致G1-S停滞。 阐明肿瘤分化的启动是如何与细胞偶联的 循环机械应更好地发挥 以成熟为基础的癌症治疗。人类生殖细胞癌 (畸胎癌)细胞株NT2/D1在RA诱导过程中滞留在G1期 神经元分化。初步数据表明，作为对RA的响应， Nt2/d1细胞呈进行性改变，细胞周期蛋白d1表达呈进行性变化。 这与细胞增殖的下降是平行的。表型成熟和 之后，细胞在G1期积累。一种抗RA的克隆， NT2/D1-R1被证明不表达维甲酸受体-γ(RARGamma)，它确实表达 未在G1期蓄积，持续过表达细胞周期蛋白D1和P53。 外源RARGamma基因表达逆转RA抗性并恢复 RA介导的细胞周期蛋白D1的下降。本建议书旨在了解RA如何 向那些导致生长抑制的细胞周期变化发出信号。第一 具体目标确定RA通过以下方式实现G1停滞的机制 已知的G1-S介体的生化活性和表达的比较 RA敏感和耐药的NT2/D1细胞的研究进展第二个具体问题 AIM确定RA诱导的细胞周期改变是否在介导 通过研究维甲酸的敏感性诱导生长抑制和成熟 被设计为过表达细胞周期蛋白D1、P53和其他突出细胞的细胞 循环组件。第三个具体目标是探讨区域资源受体在 通过单独信号传递RA诱导的细胞周期改变 维甲酸受体在RA敏感和耐药患者中的过度表达 NT2/D1细胞。RARGamma在肿瘤分化中的直接作用是 在具体目标4中由工程线路解决，以表示 显性-负RARGamma结构。这项研究针对的是 人肿瘤诱导生长抑制和分化机制的研究 细胞。这些具体目标的成功完成应有助于 维甲酸在癌症治疗和预防中的合理应用。

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.