APOPTOSIS & CELL CYCLE IN BREAST & OVARIAN CANCER CELLS

细胞凋亡

• 批准号: 6489338
• 负责人: JAY wimalasena WIMALASENA
• 金额: $ 20.33万
• 依托单位: UNIVERSITY OF TENNESSEE KNOXVILLE
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-01 至 2003-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6489338
• 关键词: BCL2 gene /protein; MCF7 cell; apoptosis; breast neoplasms; cell cycle; cell growth regulation; cyclin dependent kinase; estradiol; estrogen inhibitor; hormone regulation /control mechanism; microtubules; neoplastic cell; ovary neoplasms; p53 gene /protein; paclitaxel; protooncogene

Previous work in our laboratory has demonstrated that the paclitaxel induced initial phase of apoptosis in a variety of cell lines including MCF-7 breast cancer cells and BR ovarian cells is mediated through a Ras/Rac/Ask1/JNKK/JNK signal transduction pathway. However, the second phase of paclitaxel action is not prevented by blockade of this pathway. Recent studies on MCF-7 cells and a variety of other cell types suggests that estrogens can inhibit apoptosis, more specifically, data indicates a possible interaction between paclitaxel and estrogens in regulating apoptosis in breast cancer cells. Several studies also suggest that antiestrogens have apoptotic effects in ER positive breast Ca cells. We have accumulated preliminary evidence confirming an anti-apoptotic role for estrogens in MCF-7 cells. However, the mechanisms of estrogen action as an anti-apoptotic agent or their potential interactions with pro-apoptotic agents such as paclitaxel are totally unknown. Elucidations of these interactions is particularly significant since estrogens and microtubule interfering agents (MIAs) such as paclitaxel have clinically established roles in promotion and therapy of breast and ovarian cancer respectively. We propose that estrogens can act as anti-apoptotic agents because of their ability to regulate the Ras/Rac-JNK pathway and the Cdk/cyclin/Cdk inhibitor activity in breast and ovarian cancer cells. We have proposed the following Specific Aims to test this broad hypothesis. Specific Aim 1: Determine the role of Cdks in the apoptotic action of paclitaxel in MCF-7 and BR and BG1 (ovarian) cancer cells with the intention of elucidating the role of the cell cycle, if any, in paclitaxel action. Specific Aim 2: Analyze the putative interactions between paclitaxel and estradiol in regulating apoptosis in the above cell lines. Experiments will be designed to elucidate interaction of estrogens with the Ras/Rac/JNKK/JNK/AP1 pathway activated by paclitaxel. Specific Aim 3: Given the fact that estrogens can regulate the activity of several genes which can modulate apoptosis, we will determine potential role of c-myc, Bc12, p53, p300/CBP Akt in the anti apoptotic effects of estradiol using overexpression of wild type and dominant negative (DN) versions of the genes of interest.

我们实验室之前的工作已经证明，紫杉醇诱导多种细胞系（包括MCF-7乳腺癌细胞和BR卵巢细胞）的初始阶段凋亡是通过Ras/Rac/Ask1/JNKK/JNK信号转导途径介导的。然而，阻断这一通路不能阻止紫杉醇作用的第二阶段。最近对MCF-7细胞和其他多种细胞类型的研究表明，雌激素可以抑制细胞凋亡，更具体地说，有数据表明紫杉醇和雌激素可能在调节乳腺癌细胞凋亡中相互作用。一些研究也表明，抗雌激素对雌激素受体阳性的乳腺癌细胞有凋亡作用。我们已经积累了初步证据，证实雌激素在MCF-7细胞中具有抗凋亡作用。然而，雌激素作为抗凋亡药物的作用机制及其与促凋亡药物（如紫杉醇）的潜在相互作用尚不清楚。这些相互作用的阐明尤其重要，因为雌激素和微管干扰剂（MIAs）如紫杉醇在临床上分别在促进和治疗乳腺癌和卵巢癌中发挥作用。我们认为雌激素可以作为抗凋亡药物，因为它们能够调节乳腺癌和卵巢癌细胞中的Ras/Rac-JNK通路和Cdk/cyclin/Cdk抑制剂活性。我们提出了以下具体目标来检验这一广泛的假设。特异性目的1：确定Cdks在MCF-7、BR和BG1（卵巢癌）细胞中紫杉醇凋亡作用中的作用，目的是阐明细胞周期在紫杉醇作用中的作用（如果有的话）。具体目的2：分析紫杉醇和雌二醇在上述细胞系中调节细胞凋亡的相互作用。我们将设计实验来阐明雌激素与紫杉醇激活的Ras/Rac/JNKK/JNK/AP1通路的相互作用。具体目标3：鉴于雌激素可以调节几种可以调节细胞凋亡的基因的活性，我们将通过野生型和显性阴性（DN）基因的过表达来确定c-myc、Bc12、p53、p300/CBP Akt在雌二醇抗细胞凋亡作用中的潜在作用。