PTH-related peptide and vit D in prostate cancer growth

PTH 相关肽和维生素 D 在前列腺癌生长中的作用

• 批准号: 7238861
• 负责人: MIRIAM FALZON
• 金额: $ 25.77万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-07 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7238861
• 关键词: PTH; related; peptide; vit; prostate

DESCRIPTION (provided by applicant): Prostate cancer is the largest cause of male cancer death in the United States; many prostate cancer patients have metastatic disease at diagnosis. Vitamin D deficiency is a risk factor for prostate cancer, and 1,25-dihydroxyvitarhin D3 (1,250, the hormonally active form of vitamin D) and noncalcemic analogues have shown therapeutic benefits in clinical trials with prostate cancer patients. Prostate cancer cells produce many growth factors, including parathyroid hormone-related protein (formerly peptide, PTHrP). We show that PTHrP overexpression increases prostate cancer cell (a) proliferation; (b) adhesion to the extracellular matrix proteins collagen types I and IV, laminin, and fibronectin; (c) migration onto laminin and collagen type I; (d) invasion of Matrigel, a reconstituted basement membrane; (e) anchorage-independent cell growth; (f) cell surface expression of the pro-invasive integrin a6|34; and (g) xenograft growth in vivo. 1,250 exerts opposite effects on all these parameters, and downregulates PTHrP gene expression. Both PTHrP and integrin 04 expression are required for the anti-proliferative and anti-invasive effects of 1,250, as shown using siRNAs. We thus hypothesize that (a) PTHrP facilitates prostate cancer metastasis by upregulating pro-invasive integrin expression, and (b) the therapeutic benefits of vitamin D are mediated via both downregulatipn of PTHrP gene expression and a direct effect on integrin expression. This project seeks to understand the relationship between PTHrP, vitamin D and integrin a6p4 in prostate cancer cells, by pursuing three Aims. (1) The pathways via which PTHrP and vitamin D regulate integrin a634 expression will be investigated using siRNAs and integrin promoter deletions/transient transfection assays. Since integrin a6(34 increases cancer aggressiveness, we will determine by immunoprecipitation whether vitamin D alters the association of a6 from (34 to 31. (2) The role of PTHrP and integrin (34 in prostate cancer cell growth and bone metastasis, and the effect of concomitant vitamin D treatment, will be studied in vivo using a nude mouse model. (3) The vitamin D response elements via which vitamin D regulates PTHrP gene expression will be identified by PTHrP gene promoter deletions and transient transfection assays. Understanding the relationship between PTHrP, vitamin D, and pro-invasive integrin expression, and the molecular pathways involved, should lead to the development of new combinatorial therapeutic approaches to manage prostate cancer.

描述（由申请人提供）：前列腺癌是美国男性癌症死亡的最大原因；许多前列腺癌患者在诊断时已患有转移性疾病。维生素 D 缺乏是前列腺癌的危险因素，1,25-二羟基维生素 D3（1,250，维生素 D 的激素活性形式）和非钙血症类似物已在前列腺癌患者的临床试验中显示出治疗效果。前列腺癌细胞产生许多生长因子，包括甲状旁腺激素相关蛋白（以前的肽，PTHrP）。我们发现 PTHrP 过度表达会增加前列腺癌细胞 (a) 增殖； (b) 与细胞外基质蛋白 I 型和 IV 型胶原蛋白、层粘连蛋白和纤连蛋白的粘附； (c)迁移到层粘连蛋白和I型胶原上； (d) 侵入基质胶（一种重建的基底膜）； (e) 不依赖贴壁的细胞生长； (f) 促侵袭性整合素 a6|34 的细胞表面表达； (g)体内异种移植物生长。 1,250 对所有这些参数产生相反的影响，并下调 PTHrP 基因表达。如使用 siRNA 所示，PTHrP 和整合素 04 表达都是 1,250 的抗增殖和抗侵袭作用所必需的。因此，我们假设 (a) PTHrP 通过上调促侵袭性整合素表达来促进前列腺癌转移，(b) 维生素 D 的治疗效果是通过 PTHrP 基因表达的下调和对整合素表达的直接影响来介导的。该项目旨在通过三个目标来了解前列腺癌细胞中 PTHrP、维生素 D 和整合素 a6p4 之间的关系。 (1) 将使用 siRNA 和整合素启动子缺失/瞬时转染测定来研究 PTHrP 和维生素 D 调节整合素 a634 表达的途径。由于整合素 a6(34 增加癌症侵袭性)，我们将通过免疫沉淀法确定维生素 D 是否会改变 a6 (34) 至 31 的关联。(2) 将使用裸鼠模型在体内研究 PTHrP 和整合素 (34) 在前列腺癌细胞生长和骨转移中的作用，以及伴随维生素 D 治疗的效果。(3) 维生素 D 的反应元件 D 调节 PTHrP 基因表达将通过 PTHrP 基因启动子缺失和瞬时转染测定来鉴定。了解 PTHrP、维生素 D 和促侵袭性整合素表达之间的关系以及所涉及的分子途径，应该有助于开发新的组合治疗方法来治疗前列腺癌。