PROGESTERONE, CELL CYCLE AND CANCER

黄体酮、细胞周期和癌症

• 批准号: 6489420
• 负责人: JEFFREY W. POLLARD
• 金额: $ 35.33万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-05 至 2005-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6489420
• 关键词: carcinogenesis; cell cycle; cell cycle proteins; cell nucleus; cyclin dependent kinase; cyclins; endometrium; epithelium; estrogens; female; gene induction /repression; hormone regulation /control mechanism; immunofluorescence technique; laboratory mouse; microarray technology; phosphoprotein phosphatase; progesterone; transfection

Estrogens are the major carcinogen in the environment of most females with exposure to unopposed estrogen increasing the risk of breast and endometrial cancer. Conversely, it has become increasingly apparent that estrogens are essential for the well being of women (and men) throughout life. Progesterone acts to oppose the effects of estrogen on cell proliferation and, consequently, it is used in the treatment of endometrial cancer and it is an essential component of hormone replacement therapy designed to alleviate post-menopausal symptoms in women. It is, therefore, of fundamental importance to understand the mechanism of action of these hormones on cell proliferation. In adult ovariectomized mice, a single injection of estradiol-17beta (E2) results in the stimulation of a wave of DNA synthesis and cell proliferation that is restricted to the uterine epithelium. This proliferation is completely inhibited by pretreatment with progesterone (P4). The uterine epithelium can be isolated with great purity in a state suitable for biochemical analysis. This method together with defined hormonal regimens provides a controllable model in which to study the mechanism of action of these hormones in vivo. In tissue culture cells the cell cycle is regulated by the orderly activation of cyclins and their dependent kinases (Cdk). These include the cyclin D-Cdk4 and cyclin D-Cdk6 complexes acting early in G1 and the cyclin E-Cdk2 complex acting at the G1 to S-phase boundary. Our studies in the uterine epithelium have shown that E2 induces the re-localization of cyclin D1 and Cdk-4 to the nucleus and, results in orderly activation of cyclin-E and cyclin ACdk-2 activities and hyper-phosphorylation of pRb and p107. Progesterone pre- treatment prohibited the cyclin D1/Cdk-4 relocalization to the nucleus with a consequent inhibition of pRb and p107 phosphorylation. In addition, P4 abrogated the E2 induced cyclin E and cyclin A-Cdk2 activities. The specific aims of this grant are: 1) To determine the mechanism whereby P4 prohibits cyclin D1/Cdk4 nuclear accumulation following E2 treatment; 2) To determine the mechanism of action of P4-inhibition of Cdk-2 activation; 3) identify differentially regulated genes in the uterine epithelium following E2 treatment in the presence and absence of P4; 4) to develop methods to interfere with signaling pathways in the uterine epithelium in vivo. It is expected that by the end of the grant that the mechanisms of cyclin D1/Cdk4 exclusion can be identified and novel proteins associated with this process isolated. Furthermore, novel E2 and P4-regulated genes that play important roles in the control of epithelial cell proliferation should be identified. These studies will define specific mechanisms that may result in the development of therapeutics that would inhibit estrogen's mitogenic effects in tumors as well as in benign proliferative diseases such as endometrial polyps and endometriosis.

雌激素是大多数女性环境中的主要致癌物，暴露于无反应的雌激素，增加了乳腺癌和子宫内膜癌的风险。相反，越来越明显的是，雌激素对于一生中的女人（和男性）至关重要。孕酮的作用是反对雌激素对细胞增殖的影响，因此，它用于治疗子宫内膜癌，并且​​是旨在减轻女性绝经后症状的激素替代疗法的重要组成部分。因此，了解这些激素对细胞增殖的作用机理至关重要。在成年卵巢切除小鼠中，单次注射雌二醇-17beta（E2）会导致刺激DNA合成波和细胞增殖的波，而细胞增殖仅限于子宫上皮。孕酮预处理（P4）完全抑制了这种增殖。子宫上皮可以在适合生化分析的状态下以非常纯度分离。该方法与定义的激素方案提供了一个可控的模型，在该模型中，研究这些激素在体内的作用机理。在组织培养细胞中，细胞周期受细胞周期蛋白及其依赖激酶（CDK）的有序激活调节。其中包括作用于G1早期作用的细胞周期蛋白D-CDK4和Cyclin D-CDK6复合物，以及作用于G1到S相边界的细胞周期蛋白E-CDK2复合物。我们在子宫上皮的研究表明，E2诱导细胞周期蛋白D1和CDK-4对核的重新定位，从而有序地激活Cyclin-E和Cyclin ACDK-2活性以及PRB和P107的高磷酸化。孕激素预先处理禁止细胞周期蛋白D1/CDK-4重新定位到核，从而抑制PRB和P107磷酸化。此外，P4废除了E2诱导的细胞周期蛋白E和细胞周期蛋白A-CDK2活性。该赠款的具体目的是：1）确定P4禁止在E2处理后P4禁止细胞周期蛋白D1/CDK4核积累的机制； 2）确定CDK-2激活P4抑制作用的作用机理； 3）在存在和不存在P4的情况下，E2处理后的子宫上皮中差异调节的基因； 4）开发方法来干扰体内子宫上皮的信号通路。可以预期，在授予结束时，可以鉴定出细胞周期蛋白D1/CDK4排除的机理，并与该过程分离的新蛋白质进行鉴定。此外，应鉴定出在控制上皮细胞增殖中起重要作用的新型E2和P4调节的基因。这些研究将定义可能导致疗法发展的特定机制，从而抑制雌激素在肿瘤以及良性增殖性疾病（例如子宫内膜息肉和子宫内膜异位症）中的有丝分裂作用。