PTH-related peptide and vit D in prostate cancer growth

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-dihydroxyvitarhin D3（1，250，维生素D的代谢活性形式）和非钙类似物在前列腺癌患者的临床试验中显示出治疗益处。前列腺癌细胞产生许多生长因子，包括甲状旁腺相关蛋白（以前的肽，PTHrP）。我们发现PTHrP过表达增加前列腺癌细胞（a）增殖;（B）与细胞外基质蛋白I型和IV型胶原、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）基质胶（一种重建的基底膜）的侵袭;（e）锚定非依赖性细胞生长;（f）促侵袭整合素α 6的细胞表面表达。|34;和（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。PTHrP和整联蛋白04的表达都是1，250的抗增殖和抗侵袭作用所需的，如使用siRNA所示。因此，我们假设（a）PTHrP通过上调促侵袭整合素表达促进前列腺癌转移，和（B）维生素D的治疗益处通过PTHrP基因表达的下调和对整合素表达的直接作用介导。本项目旨在了解前列腺癌细胞中PTHrP，维生素D和整合素a6 p4之间的关系，通过追求三个目标。(1)PTHrP和维生素D调节整联蛋白α 634表达的途径将使用siRNA和整联蛋白启动子缺失/瞬时转染测定来研究。由于整联蛋白α 6 β 4增加了癌症的侵袭性，我们将通过免疫沉淀来确定维生素D是否改变了α 6 β 4至β 1的结合。(2)PTHrP和整合素β 4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，将使用裸鼠模型在体内进行研究。(3)维生素D通过其调节PTHrP基因表达的维生素D反应元件将通过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，应导致开发新的组合治疗方法来管理前列腺癌。

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.