MOLECULAR MECHANISM OF CELL CYCLE ARREST BY APIGENIN

描述：芹菜素是一种植物黄酮类化合物，已被证明具有 具有显著的化学预防活性，可抑制化学- 光诱导和紫外线诱导小鼠皮肤皮肤癌的实验研究 模特。尽管芹菜素显示出作为化学预防药物的前景， 人们对其分子作用机制知之甚少。这个 研究人员的初步结果表明，芹菜素治疗 培养的角质形成细胞产生明显的G2/M细胞周期停滞和 抑制细胞周期蛋白依赖性蛋白激酶p34cdc2的活性 该基因调控哺乳动物细胞的G2/M转变。其他内容 实验表明，芹菜素对稳态无影响。 P34cdc2Kinase的蛋白水平，但可能影响p34cdc2 磷酸化状态。在本申请中，调查人员 建议检验芹菜素起化学预防作用的假设 药物在皮肤中通过抑制诱导细胞周期停滞在G2/M期 P34cdc2激酶，是一种细胞周期蛋白依赖的激酶，负责 哺乳动物细胞的G2/M转变。以下目标将考验 这一假说在体外和体内都有，在表皮细胞中 肿瘤形成的不同阶段：(1)目标1将调查 芹菜素通过影响角质形成细胞的磷酸化抑制角质形成细胞 P34cdc2激酶的状态，从而抑制其活性。(2)目标2 将研究芹菜素是否通过作用于 细胞周期蛋白B的水平，或者通过(A)抑制细胞周期蛋白B的积累 (B)抑制细胞周期蛋白B的结合 与细胞周期蛋白依赖性激酶p34cdc2结合，或(C)促进 细胞周期蛋白抑制剂与细胞周期蛋白/细胞周期蛋白依赖性的关系 激活剂复合体。(3)目标3将调查芹菜素是否能够 诱导角质形成细胞株在不同时期发生G2/M期阻滞 关于肿瘤发生的研究。(4)Aim#4将采用UV-B致癌 在SKH-1小鼠模型中检测芹菜素对小鼠皮肤的治疗作用 可在体内抑制皮肤肿瘤细胞的生长，即使在病灶后 有肿瘤细胞存在。

DESCRIPTION: Apigenin is a plant flavonoid which has been shown to possess significant chemopreventive activity in inhibiting chemically- induced and ultraviolet light-induced skin cancer in the mouse skin model. Although apigenin shows promise as a chemopreventive agent, little is known about its molecular mechanism of action. The investigators' preliminary results indicate that apigenin treatment of cultured keratinocytes produces substantial G2/M cell cycle arrest and inhibition of p34cdc2 kinase activity, the cyclin dependent kinase which regulates G2/M transition in mammalian cells. Additional experiments indicated that apigenin had no effect on steady-state protein levels of p34cdc2 Kinase but may effect the p34cdc2 phosphorylation status. In the present application the investigators propose to test the hypothesis that apigenin acts as a chemopreventive agent in skin by inducing cell cycle arrest at G2/M via inhibition of p34cdc2 kinase, the cyclin dependent kinase which is responsible for the G2/M transition in mammalian cells. The following Aims will test this hypothesis both in vitro and in vivo, in epidermal cells at various stages of tumorigenesis: (1) Aim 1 will investigate whether apigenin arrest keratinocytes in G2/M by affecting the phosphorylation state of p34cdc2 kinase, thereby inhibiting its activity. (2) Aim #2 will study whether apigenin is arresting cells at G2/M by acting at the level of cyclin B, either by (a) inhibiting the accumulation of cyclin B during G2, (b) inhibiting the association of cyclin B with the cyclin-dependent kinase p34cdc2, or (c) promoting the association of a cyclin inhibitor with the cyclin/cyclin-dependent kinase complex. (3) Aim #3 will investigate whether apigenin is able to induce G2/M arrest in keratinocyte cell lines at various stages of tumorigenesis. (4) Aim #4 will employ the UV-B carcinogenesis model in SKH-1 mice to examine whether apigenin treatment of mouse skin can inhibit the growth of skin tumor cells in vivo even after foci of tumor cells are present.