NEUROENDOCRINE CELL SIGNALING IN PROSTATE CANCER

该建议集中于前列腺的神经内分泌（NE）细胞， 它们在促进前列腺雄激素非依赖性生长中的作用 肿瘤的 神经内分泌（NE）细胞完全分化，有丝分裂后 在正常和恶性前列腺组织中的分泌细胞。 在形态学上，NE细胞可通过其特征性的 神经元外观，其中包括存在长神经炎 突起和致密的分泌囊泡。 前列腺肿瘤 周围肿瘤上皮细胞的增殖指数 NE细胞经常升高，这表明NE细胞在一个特定的环境中起作用。 旁分泌的方式通过分泌生长诱导因子， 与疾病的发展有关 其中一些因素已经被 已确定，包括血清素，促甲状腺激素（TSH）， 降钙素、蛙皮素和生长抑素。 增加的数量 细胞也作为肿瘤进展的一部分发生，可能是由于 遗传和表观遗传因素的影响。 这些的起源 晚期前列腺癌的数量增加是不确定的，但 几项研究表明NE细胞产生于肿瘤内， 或者来自增生的基底上皮细胞，或者来自转化的 外分泌上皮细胞通过去分化或转分化， 分别 Bang等人（9）事实上已经表明，前列腺 肿瘤细胞系LNCaP和PC3M可以被诱导分化为 有丝分裂后的NE样细胞， 胞内环腺苷酸。 这些实验为 NE细胞衍生的转分化模型，并建议， 提高内部cAMP水平的生理因素可能起作用 在分化过程中。 中描述的研究的目标 这项建议是为了确定生理因素和关键 有助于NE细胞分化的信号通路 并确定NE细胞是否分泌旁分泌信号， 促进前列腺癌的生长。 为了实现这些目标， 一组激素和肽因子， 将测试LNCaP细胞中的细胞内cAMP，并且将测试信号传导途径。 将分析从最有效的分化剂发出的辐射。 此外，还将生成一个LacSwitch系统， 调节的催化的组成型活性形式的表达 蛋白激酶A亚基和用于鉴别前列腺肿瘤 细胞系转化为NE细胞。 条件培养基从这些分化 然后将测试细胞增强细胞增殖的能力， 未分化的肿瘤细胞。 最后，信号机制 还将检查调节分泌。 该项目的目标 是为了阐明调节分化的信号通路， NE细胞的分泌，并确定这些细胞的关键成分， 这些途径可以作为发展的分子靶点， 晚期雄激素非依赖性前列腺肿瘤的新疗法。

This proposal focuses on neuroendocrine (NE) cells of the prostate and role they play in promoting androgen-independent growth of prostate tumors. Neuroendocrine (NE) cells are fully differentiated, postmitotic secretory cells that populate both normal and malignant prostate tissue. Morphologically, NE cells can be identified by their characteristic neuronal appearance, which includes the presence of long neuritic processes and dense secretory vesicles in the body. In prostate tumors the proliferative index of neoplastic epithelial cells surrounding the NE cells is frequently elevated, suggesting that the NE cells act in a paracrine fashion by secreting growth-inducing factors and contributing to the progression of the disease. Several of these factors have been identified and include serotonin, thyroid stimulating hormone (TSH), calcitonin, bombesin, and somatostatin. Increases in the number of NE cells also occur as part of tumor progression, presumably due to the influence of both genetic and epigenetic factors. The origin of these increased numbers in later stage prostatic carcinomas is uncertain, but several studies suggest that NE cells arise from within the tumor, either from a hyperplastic basal epithelial cell or from a transformed exocrine epithelial cell by de-differentiation or trans-differentiation, respectively. Bang et al. (9) have in fact shown that the prostate tumor cell lines, LNCaP and PC3M, can be induced to differentiate into post-mitotic NE-like cells upon addition of agents that increase intracellular cyclic AMP. These experiments provide evidence for the transdifferentiation model of NE cell derivation and suggest that physiological factors that elevate internal cAMP levels may play a role in the differentiation process. The goal of the studies described in this proposal is to identify physiological factors and critical signaling pathways that contribute to the differentiation of NE cells and to determine whether NE cells secrete paracrine signals which potentiate the growth of prostate carcinomas. To accomplish these aims, a panel of hormones and peptide factors that cause elevations in intracellular cAMP in LNCaP cells will be tested, and signaling pathways emanating from the most potent differentiating agents will be analyzed. In addition, a LacSwitch system will be generated that directs the regulated expression of a constitutively active form of the catalytic subunit of protein kinase A and used to differentiate prostate tumor cells lines to NE cells. Conditioned medium from these differentiated cells will then be tested for its ability to enhance proliferation of non-differentiated tumor cells. Finally, the signaling mechanisms regulating secretion will also be examined. The goals of the project are to elucidate signaling pathways that regulate differentiation and secretion of NE cells and to identify critcal components of these pathways that could serve as molecular targets for the development of novel therapies for late stage, androgen-independent prostate tumors.