Targeting Apoptosis Signaling in Breast Cancer Cells

靶向乳腺癌细胞中的凋亡信号传导

• 批准号: 6723402
• 负责人: KAPIL BHALLA
• 金额: $ 26.73万
• 依托单位: H. LEE MOFFITT CANCER CTR & RES INST
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6723402
• 关键词: BCL2 gene /protein; Bax gene /protein; RNA interference; RNase protection assay; apoptosis; athymic mouse; biological signal transduction; breast neoplasms; cell growth regulation; clinical research; clinical trials; combination cancer therapy; combination chemotherapy; confocal scanning microscopy; drug screening /evaluation; epothilon; flavopiridol; human subject; human therapy evaluation; immunocytochemistry; neoplasm /cancer classification /staging; paclitaxel; patient oriented research; phosphorylation; protein kinase; protein structure function; survivin

DESCRIPTION (provided by applicant): Tubulin polymerizing agents (TPA) taxotere and Epothilone B (EpoB) are highly active drugs against human breast cancer. Intracellularly, these agents bind to beta tubulin, promote microtubule bundling and induce mitotic arrest, which triggers the intrinsic (mitochondrial) pathway of apoptosis. However, the molecular mechanisms that link TPA-induced microtubular damage and mitotic arrest to the mitochondrial release of the death promoters, e.g., cytochrome c (cyt c), Smac and Omi/HtrA2, which promote the activation of effector caspases involved in apoptosis, remain to be elucidated. Survivin is a member of the antiapoptotic IAP family, and Bim is a BH3-only pro-apoptotic member of the Bcl-2 family of proteins; both are associated with the microtubules of the mitotic spindle. While downregulation of survivin levels induces apoptosis and sensitizes cancer cells to TPA, microtubule damage induces Bim to translocate to the mitochondria and neutralize the anti-apoptotic activity of Bcl-2/Bcl-XL. Recently, exposure to flavopiridol (FP), which depletes the levels of IAP and some Bcl-2 family members, following treatment with TPA has been shown to enhance TPA induced apoptosis. The working hypothesis of this project is that the strategies that downregulate survivin levels and/or function, or reduce the level and/or function of the antiapoptotic Bcl-2 and IAP proteins, would potentiate TPA-induced apoptosis as well as improve the clinical response of TPA + FP-based therapy of breast cancer. The specific aims of the project are: 1) To determine the role of survivin and Aurora 2 kinase during TPA-induced in vitro mitotic arrest and apoptosis of human breast cancer cells. 2) To determine the role of Bim and Bcl-2 family of proteins as therapeutic targets in potentiating TPA-induced in vitro mitochondrial signaling for apoptosis in breast cancer cells. 3) To determine the effects of in vitro modulation of the levels and activity of the IAP family of proteins on TPA-induced apoptosis in human breast cancer cells. 4) To determine the predictive value of the expression of survivin, Bim, Aurora 2 kinase, Bcl-2 and IAP family of proteins for the clinical response to treatment with the sequential combination of taxotere and flavopiridol in patients with stage IV breast cancers. These translational studies would elucidate the molecular determinants that are not only predictors of response to TPA + FP but may also be promising therapeutic targets in novel treatments of human breast cancer.

描述（申请人提供）： 微管蛋白聚合剂（TPA）泰索帝和埃坡霉素B（EpoB）是抗人类乳腺癌的高活性药物。在细胞内，这些药物与 β 微管蛋白结合，促进微管成束并诱导有丝分裂停滞，从而触发细胞凋亡的内在（线粒体）途径。然而，将 TPA 诱导的微管损伤和有丝分裂停滞与死亡启动子（例如细胞色素 c (cyt c)、Smac 和 Omi/HtrA2）线粒体释放联系起来的分子机制，这些启动子促进参与细胞凋亡的效应器半胱天冬酶的激活，仍有待阐明。 Survivin 是抗凋亡 IAP 家族的成员，Bim 是 Bcl-2 蛋白家族中仅 BH3 的促凋亡成员；两者都与有丝分裂纺锤体的微管有关。虽然生存素水平下调会诱导细胞凋亡并使癌细胞对 TPA 敏感，但微管损伤会诱导 Bim 易位至线粒体并中和 Bcl-2/Bcl-XL 的抗细胞凋亡活性。最近，在 TPA 治疗后暴露于黄酮吡醇 (FP) 已被证明可以增强 TPA 诱导的细胞凋亡，该药物会消耗 IAP 和一些 Bcl-2 家族成员的水平。该项目的工作假设是，下调生存素水平和/或功能，或降低抗凋亡 Bcl-2 和 IAP 蛋白的水平和/或功能的策略，将增强 TPA 诱导的细胞凋亡并改善临床反应基于 TPA + FP 的乳腺癌治疗。该项目的具体目标是： 1) 确定生存素和 Aurora 2 激酶在 TPA 诱导的人乳腺癌细胞体外有丝分裂停滞和凋亡过程中的作用。 2) 确定 Bim 和 Bcl-2 蛋白家族作为治疗靶点在增强 TPA 诱导的乳腺癌细胞凋亡的体外线粒体信号传导中的作用。 3) 确定体外调节 IAP 家族蛋白的水平和活性对 TPA 诱导的人乳腺癌细胞凋亡的影响。 4) 确定生存素、Bim、Aurora 2 激酶、Bcl-2 和 IAP 家族蛋白的表达对 IV 期乳腺癌患者泰素帝和黄吡醇序贯联合治疗的临床反应的预测价值。这些转化研究将阐明分子决定因素，这些决定因素不仅是 TPA + FP 反应的预测因素，而且还可能成为人类乳腺癌新疗法中有希望的治疗靶点。