BONE MATRIX BOUND GROWTH FACTORS AND BREAST CANCER

描述：乳腺癌常见的、使人衰弱的并发症是 当癌细胞转移到骨骼时造成的骨骼破坏。 拟议研究的基本假设是矩阵界限 骨骼中的生长因子可能有助于将其定义为生长的肥沃土壤 乳腺癌转移的可能性，并影响其破坏骨骼的潜力。 这项建议的目标是研究骨基质结合的作用。 转化生长因子-β(TGFb)对骨破坏的调节作用 转移性乳腺癌细胞通过刺激产生 甲状旁腺激素相关蛋白(PTHrP)--一种强大的骨吸收 因素。特定的目标1将确定骨基质结合的TGFb是否 乳腺癌时观察到甲状旁腺素rP产生增加的原因 细胞生长在骨基质上。这将在体外通过使用 TGFb中和抗体的研究和骨基质制剂的使用 缺乏TGFb-1基因的小鼠。体外研究将得到证实 利用体内转移模型比较甲状旁腺素相关蛋白的产生和溶骨作用 正常和TGFb-L缺陷小鼠乳腺癌细胞的损伤。在……里面 特异性靶点2和3骨基质释放的分子机制 将研究乳腺癌细胞结合的TGFb。因为蛋白质降解 潜伏的转化生长因子β结合蛋白-1的切割 (LTBP-1)是骨释放基质结合的TGFb的重要机制 细胞，特定的目标2将确定是否使用类似的机制 乳腺癌细胞。这将通过测量LTBP-1和 人乳腺癌细胞在放射性标记骨基质上生长的TGFb 免疫检测方法。在特定目标3中，蛋白水解性裂解位点 在LTBP-1中将被映射。然后将设计拮抗肽，并 测试以确定将抑制乳房切割LTBP-1的多肽 从而抑制骨基质中TGFb的释放。自.以来 必须激活潜伏的TGFP，才能对乳房产生影响 癌细胞，特异性靶点4将检测乳腺癌的能力 细胞激活基质释放的潜伏的TGFb。这将使用以下工具完成 结合Western blotting检测肿瘤生长因子b的生物测定。这项研究将 为研究乳房之间复杂的相互作用提供了一种新的途径 癌症细胞和骨骼微环境，并将解决一般 宿主组织中的基质结合生长因子是否会影响 转移癌细胞的行为。阻滞骨的释放 乳腺癌细胞与基质结合的TGFb可能作为一种 减少癌症相关骨溶解和缓解的新治疗策略 骨转移性乳腺癌患者的痛苦。

DESCRIPTION: A frequent and debilitating complication of breast cancer is the bone destruction that results when the cancer cells metastasize to bone. The underlying hypothesis for the proposed studies is that matrix-bound growth factors in bone may help define it as a fertile ground for the growth of breast cancer metastases and influence their bone-destructive potential. The goal of this proposal is to examine the role of bone matrix-bound transforming growth factor beta (TGFb) in regulating the bone destructive capacity of metastatic breast cancer cells through stimulating production of parathyroid hormone related protein (PTHrP), a powerful bone resorbing factor. Specific Aim 1 will determine whether bone matrix-bound TGFb is responsible for the increase in PTHrP production observed when breast cancer cells are grown on bone matrix. This will be done in vitro through the use of TGFb neutralizing antibodies and the use of bone matrix preparations from mice which lack the gene for TGFb-1. In vitro studies will be confirmed using an in vivo metastasis model to compare PTHrP production and osteolytic lesions by breast cancer cells in normal and TGFb-l deficient mice. In Specific Aims 2 and 3 the molecular mechanism for release of bone-matrix bound TGFb by breast cancer cells will be investigated. Since proteolytic cleavage of the latent transforming growth factor beta binding protein-1 (LTBP-1) is an important mechanism for release of matrix-bound TGFb by bone cells, Specific Aim 2 will determine whether a similar mechanism is used by breast cancer cells. This will be done by measuring release of LTBP-1 and TGFb by breast cancer cells grown on radiolabeled bone matrix using immunodetection methods. In Specific Aim 3 the proteolytic cleavage sites in LTBP-1 will be mapped. Antagonist peptides will then be designed and tested to identify peptides which will inhibit cleavage of LTBP-1 by breast cancer cells and therefore inhibit release of TGFb from bone matrix. Since latent TGFP must be activated in order to exert its effects on the breast cancer cells, Specific Aim 4 will examine the ability of the breast cancer cells to activate matrix-released latent TGFb. This will be done using bioassays for TGFb in conjunction with Western blotting. This study will provide a new approach for studying the complex interactions between breast cancer cells and the bone microenvironment and will address the general question of whether matrix-bound growth factors in host tissues influence the behavior of metastatic cancer cells. Blocking the release of bone matrix-bound TGFb by breast cancer cells may potentially be developed as a new treatment strategy to reduce cancer-associated osteolysis and alleviate the suffering of patients with bone metastatic breast cancer.