HUMORAL FACTOR INTERACTIONS IN HYPERCALCEMIA OF CANCER

本提案的总体目标是研究 控制甲状旁腺相关蛋白（PTHrP）分泌和mRNA 在正常和肿瘤性角质形成细胞中表达。 据推测 在PTHrP的病理生理学方面存在重要差异 与肿瘤性角质形成细胞相比， PTHrP mRNA 可能会以分化调节的方式表达， 正常的角质形成细胞，并将显示出分泌的极性（远离 来自表皮的基底膜）。 相反，肿瘤性 角质形成细胞可能改变了PTHrP mRNA分泌的调节， 表达，并且由于缺乏 一种基底膜。 该五年计划有三个主要目标：（1）调查 PTHrP mRNA表达、转录速率和稳定性的调节 细胞因子（TGF α、TGF β和IL-1）、1，25-二羟基维生素D和 正常人角质形成细胞和鳞状细胞癌细胞中钙离子的研究 在单层和三维细胞培养中生长的细胞系，（2）研究 影响PTHrP分泌试剂对PTHrP分泌的调节和极性 蛋白激酶C和细胞内钙，通过抑制剂/刺激剂 囊泡分泌，以及基底膜成分的存在 (3)探讨PTHrP mRNA表达与细胞凋亡调控的关系。 角质形成细胞增殖过程中组织特异性基因表达 （c-myc和H3组蛋白基因）和分化（外皮蛋白，聚丝蛋白， 以及角蛋白1和6基因）。 三维细胞培养的使用将 是调查的一个重要方面，将允许正常的 体外表皮角质形成细胞的分化，并进行比较 肿瘤性角质形成细胞。 这些研究将确定各种因素， 调节PTHrP合成和分泌的条件。 信息 PTHrP的细胞生物学对于确定其在 恶性肿瘤体液性高钙血症的病理状态， 上皮细胞的正常生理学，以及其 可以控制分泌和合成。

The overall goal of this proposal is to investigate mechanisms which control parathyroid hormone-related protein (PTHrP) secretion and mRNA expression in normal and neoplastic keratinocytes. It is hypothesized that there are important differences in the pathophysiology of PTHrP regulation in normal compared to neoplastic keratinocytes. PTHrP mRNA will likely be expressed in a manner regulated by differentiation in normal keratinocytes and will demonstrate polarity of secretion (away from the basement membrane of the epidermis). In contrast, neoplastic keratinocytes likely have altered regulation of PTHrP mRNA secretion and expression and do not demonstrate polarity of secretion due to the lack of a basement membrane. The five-year proposal has three major objectives: (1) investigate the regulation of PTHrP mRNA expression, transcription rate, and stability by cytokines (TGFalpha, TGFbeta, and IL-1), 1,25-dihydroxyvitamin D, and calcium in normal human keratinocytes and squamous cell carcinoma cell lines grown in monolayer and 3-dimensional cell cultures, (2) investigate the regulation and polarity of PTHrP secretion by agents which affect protein kinase C and intracellular calcium, by inhibitors/stimulators of vesicular secretion, and by the presence of basement membrane components (3) determine the relationship of PTHrP mRNA expression to the regulation of tissue-specific gene expression during keratinocyte proliferation (c-myc and H3 histone genes) and differentiation (involucrin, filaggrin, and keratin 1 and 6 genes). The use of 3-dimensional cell cultures will be an important aspect of the investigations and will permit normal differentiation of epidermal keratinocytes in vitro and allow comparisons to neoplastic keratinocytes. These studies will define factors and conditions that regulate PTHrP synthesis and secretion. Information on the cellular biology of PTHrP is necessary to determine its role in the pathologic state of humoral hypercalcemia of malignancy, its role in the normal physiology of epithelial cells, and mechanisms by which its secretion and synthesis can be controlled.