BONE MATRIX BOUND GROWTH FACTORS AND BREAST CANCER

描述：乳腺癌的一个常见的和衰弱的并发症是 当癌细胞转移到骨骼时导致的骨骼破坏。 拟议研究的基本假设是， 骨骼中的生长因子可能有助于将其定义为生长的沃土 乳腺癌的转移，并影响其骨破坏的潜力。 这项提议的目的是研究骨基质结合的作用， 转化生长因子β（TGF β）在调节骨破坏性 转移性乳腺癌细胞的能力，通过刺激生产 甲状旁腺激素相关蛋白（PTHrP），一种强大的骨吸收蛋白， 因子 特异性目的1将确定骨基质结合的TGF β是否是 负责增加PTHrP生产时观察到乳腺癌 细胞在骨基质上生长。 这将在体外通过使用 TGF β中和抗体和使用骨基质制剂， 缺乏TGF β-1基因的小鼠。 将确认体外研究 使用体内转移模型比较PTHrP产生和溶骨性 在正常和TGFb-1缺陷小鼠中通过乳腺癌细胞的损伤。 在 具体目标2和3骨基质释放的分子机制 将研究乳腺癌细胞结合的TGF β。 由于蛋白水解 潜在转化生长因子β结合蛋白-1的切割 LTBP-1是骨释放基质结合TGF β的重要机制， 具体目标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的释放来完成， 使用放射性标记的骨基质上生长的乳腺癌细胞的TGFb 免疫检测方法。 在具体目标3中，蛋白水解切割位点 LTBP-1将被映射。 然后设计拮抗剂肽， 测试以鉴定将抑制乳腺癌对LTBP-1的切割的肽 癌细胞，并因此抑制TGF β从骨基质释放。 以来 为了发挥其对乳腺的作用，必须激活潜在的TGF β 癌细胞，具体目标4将检查乳腺癌的能力， 细胞以激活基质释放的潜伏性TGF β。 这将使用 结合蛋白质印迹进行TGF β的生物测定。 本研究将 提供了一种新的方法来研究乳房之间的复杂相互作用， 癌细胞和骨微环境，并将解决一般 宿主组织中的基质结合生长因子是否影响 转移性癌细胞的行为 阻碍了骨骼的释放 乳腺癌细胞的基质结合TGF β可能会成为一种潜在的 新的治疗策略，以减少癌症相关的骨质溶解和缓解 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.