Pathogenesis of Metastatic Bone Lesion and Development of Methods for Its Diagnosis and Treatment

为了阐明骨转移性病变的发生机制，建立诊断和治疗方法，本研究进行了以下研究：1.肿瘤细胞与骨基质和基质细胞粘附的影响：许多具有转移潜能的肿瘤细胞表达α 4 β 1整合素，骨髓基质细胞（BMSC）组成性表达可与α 4 β 1整合素结合的血管细胞粘附分子（VCAM）-1。我们已经证明，抗VCAM-1或抗α 4 β 1整联蛋白抗体可以抑制克隆性黑色素瘤细胞B16与BMSC的粘附，并且这些抗体对粘附的抑制阻断了粘附诱导的BMSC向成骨细胞分化的抑制。B16细胞与BMSC的粘附也促进了BMSC支持的破骨细胞的形成，而抗VCAM-1或抗α 4 β 1整合素抗体预处理可抑制B16细胞粘附促进的破骨细胞形成。这些 关于我们 结果表明，通过α 4 β 1整联蛋白与BMSC的结合，肿瘤细胞与BMSC的粘附不仅导致成骨细胞分化的抑制，而且还导致破骨细胞形成的刺激。肿瘤细胞与BMSC粘附引起的这些变化可能在转移性骨病变的建立和扩展中起重要作用。2. annexin II在肿瘤细胞刺激骨吸收中的作用：我们克隆了人annexin II作为破骨细胞形成的刺激因子的cDNA，并建立了过表达annexin II的乳腺癌细胞系。我们现在已经建立了稳定表达反义膜联蛋白II RNA的细胞系，以阻断膜联蛋白II的表达。使用这些细胞系，我们正在分析这些细胞系与骨髓细胞共培养对破骨细胞形成和骨吸收的影响。这些研究将使我们能够阐明肿瘤细胞产生的膜联蛋白II在增强骨转移性病变的骨吸收中的作用。3.骨转移对骨转换的影响：检测了双膦酸盐（一种有效的骨吸收抑制剂）对骨转移性病变发展的影响。骨代谢标志物评估的骨吸收抑制与肿瘤标志物评估的转移性病变程度之间存在显著相关性。这些结果表明，抑制骨吸收也可以抑制转移性骨病变的发展。少

In order to clarify the mechanism of develoment as well as to establish methods for the diagnosis and treatment of metastatic bone lesions, the following studies were performed :1.Effects of adhesion of tumor cells to bone matrix and stromal cells : Many tumor cells that have metastatic potential express alpha4beta1 integrin, and bone marrow stromal cells (BMSC) constitutively express vascular cell adhesion molecule (VCAM)-1 that can bind to alpha4beta1 integrin. We have demonstrated that anti-VCAM-1 or anti-alpha4beta1 integrin antibody can inhibit adhesion of clonal melanoma cells, B16, to BMSC,and that the inhibition of adhesion by these antibodies blocks the adhesion-induced inhibition of BMSC differentiation into osteoblasts. The adhesion of B16 cells with BMSC also enhanced osteoclast formation supported by BMSC.Furthermore, pretreatment with anti-VCAM-1 or anti-alpha4beta1 integrin antibody caused an inhibition of osteoclast formation enhanced by the adhesion of B16 cells. These … More results demonstrate that adhesion of tumor cells with BMSC via the binding of alpha4beta1 integrin with BMSC causes not only the inhibition of osteoblastic differentiation but also the stimulation of osteoclast formation. These changes caused by the adhesion of tumor cells with BMSC may play an important role in the establishment and expansion of metastatic bone lesions.2.Role of annexin II on the stimulation of bone resorption by tumor cells : We have cloned cDNA for human annexin II as a stimulatory factor of osteoclast formation, and established a breast cancer cell line over expressing annexin ii. We now have established cell lines that stably express antisense annexin II RNA to block the expression of annexin II.Using these cell lines, we are in the process of analyzing the effect of co-culture of these cell lines with bone marrow cells on osteoclast formation and bone resorption. These studies should enable us to clarify the role of annexin II produced by tumor cells on the enhancement of bone resorption at metastatic bone lesions.3.Effect of bone metastasis on bone turnover : The effect of bisphosphonates, a potent inhibitor of bone resorption, on the development of metastatic bone lesions was examined. These was a significant correlation between the inhibition of bone resorption assessed by bone metabolic markers and the extent of metastatic lesions assessed by tumor markers. These results suggest that inhibition of bone resorption can also suppress the development of metastatic bone lesions. Less