Increased Expression of Bone Sialoprotein in Bone Metastases Compared with Visceral Metastases in Human Breast and Prostate Cancers

Abstract

The recent demonstration that bone sialoprotein (BSP) is expressed in osteotropic cancers suggests that this bone matrix protein might be implicated in the preferential seed and growth of metastatic cells in bone. High expression of BSP in breast and prostate primary carcinomas is associated with progression and bone metastases development. The exact mechanisms by which BSP may favor bone metastases formation are not clearly established yet. Although BSP expression has been detected in breast, prostate, lung, thyroid, and neuroblastoma primary tumors, no information regarding its expression in metastases is available to date. In this study, we have examined BSP expression in 15 bone and 39 visceral metastatic lesions harvested from 8 breast cancer patients and 7 prostate cancer patients who died of disseminated disease. We were able to retrieve the primary lesions from 5 of the 8 breast cancer patients as well as from all 7 prostate cancer patients.

Effect of Chitosan on Expression of Osteogenic Genes during the Healing of Rat Extraction Socket

“…BSP is expressed by several cell types associated with mineralized tissues but is expressed in abundance by osteoblasts. As well, BSP has been found to be expressed at pathological sites of mineralization such as microcalcifications in breast, thyroid and prostate neoplasms 26) and atherosclerotic plaques 27) . Even though there is ample evidence to suggest that BSP is a marker of osteoblast differentiation and the onset of mineral formation, there is no direct evidence suggesting the protein has an effect on either of these processes in vivo.…”

“…Up-regulation of various types of biologic markers has been reported in the presence of chitosan in several cell culture studies and animal studies [29][30][31][32] . Waltregny et al 26) reported that BSP is an osteoblastic differentiation marker and has functions as a hydroxyapatite nucleator. Lin and Chen 33) assayed the biological responses of osteoblast including cell proliferation, viability, morphology, type 1 collagen expression, alkaline phosphatase activity, and mineralization.…”

Of mice and (wo)men: Mouse models of breast cancer metastasis to bone

“…(27,28) Breast cancer cells decorate themselves with bone matrix proteins such as bone sialoprotein and OPN, enabling bone stromal cells expressing integrins to trap them. (25,29,30) There are similarities between stroma of the primary mammary tumors and those of the bone marrow, which may contribute to the ability of breast cancer cells to survive and proliferate in bone. Both microenvironments contain conserved stromal and basement membrane components (i.e., collagen type I, laminin, and fibronectin), as well as distinctive components; for example, many breast carcinomas express OPN.…”

<b>Effects of Thalidomide on Bone Sialoprotein Gene Transcription </b>

“…The temporo-spatial deposition of BSP into the extracellular matrix of bone (11,12) and the ability of BSP to nucleate hydroxyapatite crystal formation (13) indicate a potential role for BSP in the initial mineralization of bone. BSP is also expressed in several pathologies in which mineralization occurs including malignant breast cancer where it is associated with the formation of ectopic hydroxyapatite microcrystals (14)(15)(16). Thus, regulation of BSP gene transcription appears to be important in the differentiation of osteoblasts, for bone matrix mineralization and for pathologic mineralization.…”