Study On The Role Of Bone Sialoprotein In The Metastasis Of Breast Cancer To Bone

Breast cancer is one of the malignancies that threaten the health of women, which is rated as the first killer in women malignancy. However, primary carcinoma is not the direct reason to cause the death of most patients with breast cancer and the malignancy metastasis is the truth. While skeletal is one of the most common target organs for breast cancer. In order to prevent and remedy the breast cancer effectively, intensive research related to the mechanism of breast cancer metastasis to bone should be undertaken.Human bone sialoprotein (hBSP) is an acid glycoprotein in extracellular matrix and highly restricted to mineralized connective tissues, such as bone, teeth and cartilage calcified. It is mainly expressed and secreted mainly by osteoblasts, osteoclasts and chondrocyte. BSP is related to tissue mineralization and some bone metabolizing diseases. Currently, BSP has been found playing an important role in tumour metastasis to bone, arteriosclerasis and angiogenesis. Therefore, studies on BSP bioactivity and acting mechanism could provide a better solution for diagnosis and treatment of breast cancer metastasis to bone.The purpose of this study was to determine the role of BSP in the homing of cancer cells and to provide insights of BSP in physiological and pathological processes. Developing breast cancer cells with stable hBSP expression is key point of studying the role of BSP in breast cancer cells metastasizing to bone. In this paper, the recombinant eukaryon expression vectors of hBSP were constituted, and transfected into breast cancer cells. The research on the role of hBSP in vitro and in vivo was undertaken.Firstly, the hbsp gene with secreted signal peptide was sub-cloned by PCR with pB-hBSP as template and primers designed according to pIRES2-EGFP vector and hbsp cDNA sequence. Recombinant pIRES2-hBSP-EGFP, which can express and secrete hBSP, was constructed by the recombination of PCR fragment and vector pIRES2-EGFP. The expression of hBSP is independent not together with GFP and can be secreted to extra-cells. The method of constructing recombinant plasmid, pID-hBSP-EGFP, as follows: hbsp gene fragment without secreted signal peptide was inserted into the eukaryon expression vector, pDisplay?, which allowed exogenous protein express on the surface of mammalian cell. Hence the recombinant vector, pDisplay-hBSP, was constituted. Subsequently, as the same methods, the fragment of...