Ceramide synthase as a therapy target in prostate cancer

神经酰胺合酶作为前列腺癌的治疗靶点

• 批准号: 6870063
• 负责人: ADRIANA HAIMOVITZ-FRIEDMAN
• 金额: $ 30.72万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-09 至 2010-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6870063
• 关键词: acyltransferase; antineoplastics; apoptosis; athymic mouse; cell line; ceramides; diacylglycerols; lipid metabolism; neoplasm /cancer transplantation; phorbols; phosphatidylinositol 3 kinase; prostate neoplasms; protein kinase C; radiation resistance; radiosensitizer; serine threonine protein kinase; tumor suppressor proteins

DESCRIPTION (provided by applicant): The goal of this project is to develop modulators of radiation response able to overcome radiation resistance in human prostate tumor cells. Although radiation is able of permanently eradicate localized human prostate tumors, nearly 30% of patients treated with potentially curative radiotherapy relapse at the sites of the irradiated tumor due to residual radiation-resistant clonogens. In this application we propose to explore the mechanisms of resistance to radiation-induced apoptosis for the highly resistant, well-characterized human prostate cancer cell lines-LNCaP and CRW22Rv 1, Our preliminary data Show that activation of protein kinase C (PKC) isoforms by the phorbol ester 12,O-tetradecanoyl phorbol-13-acetate, (TPA), induces a moderate apoptotic response in these tumor cells, and sensitizes them towards radiation, induced apoptosis. We also showed that this apoptotic response is mediated by the enzyme ceramide synthase (CS) and de novo synthesis of ceramide. CS activity was previously reported by us to be negatively regulated by the Ataxia Telangiectasia-Mutated (ATM) gene. Our preliminary studies related to this application showed that in LNCaP and CRW22Rvl cells, TPA reduces ATM levels. We observed a similar reduction in ATM protein levels and radiosensitization using a diacylgycerol (DAG)-lactone, HK654, or antisense oligonucleotides to ATM (AS-ATM-ODNs). In this project, we propose to define the involvement of PKCa and PKC5 in TPAinduced apoptosis via activation of the ATM-CS pathway. We will also study the mechanisms of CS involvement in mitochondrial apoptosis, ceramide generation within the mitochondria, and the interaction between ceramide, PKC6 and/or Bax. Finally, we propose to study the role of the ATM-CS pathway in vivo in LNCaP and CWR22Rvl tumors growing orthotopically in nude mice. We will study the response to TPA ( radiation in response to both single-dose radiation as well as to fractionated radiation and will correlate tumor growth in these animals with tissue readouts. The proposed Specific Aims are interactive and address new and heretofore unknown mechanisms of TPA(radiation-induced cell death in prostate cancer cells and prostate animal models. Our research plan presents a signaling-based approach, to investigate new I hypotheses, about mechanisms of radiation resistance, which could provide a basis for modulation of the l radiation response in resistant human prostate tumor clones, with potential for clinical applications in the radiation management of human prostate cancer.

描述（由申请人提供）：该项目的目标是开发能够克服人类前列腺肿瘤细胞辐射抗性的辐射反应调节剂。虽然放射能够永久根除局限性的人类前列腺肿瘤，但近30%接受有治愈潜力的放射治疗的患者由于残留的耐辐射克隆原而在照射肿瘤部位复发。在本应用中，我们提出探索高耐药、特征明确的人前列腺癌细胞lncap和CRW22Rv 1抵抗辐射诱导凋亡的机制。我们的初步数据表明，磷酸酯12，o -十四烷醇磷酸-13-乙酸（TPA）激活蛋白激酶C （PKC）异构体，在这些肿瘤细胞中诱导适度的凋亡反应，并使它们对辐射诱导的凋亡敏感。我们还发现这种凋亡反应是由神经酰胺合成酶（CS）和神经酰胺的从头合成介导的。我们之前报道过CS活性受到共济失调毛细血管扩张突变（ATM）基因的负调控。我们与该应用相关的初步研究表明，在LNCaP和CRW22Rvl细胞中，TPA降低ATM水平。我们观察到使用二酰基甘油(DAG)-内酯，HK654或反义寡核苷酸对ATM （AS-ATM-ODNs）的ATM蛋白水平和放射致敏性的类似降低。在这个项目中，我们提出通过激活ATM-CS通路来确定PKCa和PKC5在tpain诱导的细胞凋亡中的作用。我们还将研究CS参与线粒体凋亡、线粒体内神经酰胺生成以及神经酰胺、PKC6和/或Bax之间相互作用的机制。最后，我们提出在体内研究ATM-CS通路在LNCaP和CWR22Rvl裸小鼠原位生长肿瘤中的作用。我们将研究TPA辐射对单剂量辐射和分次辐射的反应，并将这些动物的肿瘤生长与组织读数联系起来。提出的特定目标是相互作用的，并解决了TPA(辐射诱导前列腺癌细胞和前列腺动物模型中细胞死亡的新的和迄今未知的机制。我们的研究计划提出一种基于信号传导的方法，探讨辐射耐药机制的新假设，为耐药人类前列腺肿瘤克隆的辐射反应调节提供基础，在人类前列腺癌的放射治疗中具有潜在的临床应用价值。