TUMOR CELL-DERIVED OSTEOCLAST GROWTH FACTOR

尽管其在维持健康骨组织中的重要作用， 破骨细胞仍然是一种知之甚少的细胞。 的长期目标 这项建议旨在加深我们对规例的了解， 破骨细胞的发育。 我们最近的研究表明， 特征性高钙血症诱导小鼠乳腺肿瘤 癌细胞产生一种新的生长因子， 产生具有破骨细胞特征的细胞的祖细胞。 是 我们假设该因子是破骨细胞的生长调节因子， “破骨细胞集落刺激因子”（O-CSF），负责 这种肿瘤引起的过度骨吸收。 这一假设将是 通过进一步表征骨骼中的反应细胞进行测试， 骨髓和明确的生化和功能研究的分子。 将通过共培养来研究对该因子有反应的细胞 用骨头碎片来证明骨头的挖掘。 破骨细胞集落 通过生化蛋白分离纯化刺激因子 分离程序，然后进行氨基酸测序和克隆， cDNA;重组分子将通过分子克隆获得 技术. 骨生长因子的生理作用 将通过注射来研究高钙血症的吸收和诱导 将重组分子导入正常和骨硬化小鼠， 骨组织化学和形态计量分析以及血清分析 钙 我们的方法是通过克隆分析破骨细胞， 骨髓祖细胞将带来一个新的见解， 破骨细胞的调节。 某些肿瘤是丰富的生长来源 已知影响宿主功能的因素，例如严重的 高钙血症 小鼠系统中O-CSF的分子特征 将使我们能够在人类中扩展这种分子的研究， 未来，将有助于了解各种骨骼疾病， 如骨质疏松症和骨硬化症，以及体液性 恶性肿瘤的高钙血症，一种严重的并发症， 癌症患者。

Despite its important role in the maintenance of healthy bone tissue, the osteoclast is still a poorly understood cell. The long term objective of this proposal is to increase our understanding of the regulation and development of osteoclasts. Our recent studies have shown that a well characterized hypercalcemia-inducing murine mammary tumor, CE mammary carcinoma, produces a new growth factor which stimulates bone marrow progenitors that give rise to cells with osteoclast characteristics. It is our hypothesis that this factor is the growth regulator of the osteoclast, "osteoclast-colony stimulating factor" (O-CSF), and is responsible for excessive bone resorption induced by this tumor. This hypothesis will be tested by further characterization of the responding cells in the bone marrow and definitive biochemical and functional studies of the molecule. The cells responding to this factor will be investigated by co-cultivation with bone pieces to demonstrate bone excavation. The osteoclast colony stimulating factor will be isolated and purified by biochemical protein separation procedures, followed by amino acid sequencing and cloning of cDNA; the recombinant molecule will be obtained by molecular cloning techniques. The physiological role of the growth factor for bone resorption and induction of hypercalcemia will be investigated by injecting the recombinant molecule into normal and osteopetrotic mice, by performing histochemical and morphometric analysis of bones and by analysis of serum calcium. Our approach to the studies of osteoclasts by clonal analysis of bone marrow progenitors will bring a new insight into the molecular regulation of osteoclasts. Certain tumors are abundant sources for growth factors and are known to influence functions of the host, such as severe hypercalcemia. Molecular characterization of the O-CSF in murine system will allow us to extend the studies of such a molecule in human in the future and will contribute to the understanding of various bone disorders, such as osteoporosis and osteopetrosis, as well as for humoral hypercalcemia of malignancy, a serious complication associated with certain cancer patients.