The relationship between bone metastasis from human breast cancer and integrin αvβ3 expression

Background: Osteoclast activation plays an essential role in the development of bone metastasis (BM). Integrin alpha(v)beta(3) mediates the attachment of osteoclasts to bone matrix and it is overexpressed in bone-residing breast cancer cells. We studied BM from breast cancer in relation to its Integrin alpha(v)beta(3) expression. Materials and Methods: Integrin alpha(v)beta(3) expression in 4 human breast cancer cell lines (MDA-MB-231, MDA-MB-435, MKL-4 and T-47D) was determined by immunohistochemistry, flow cytometry and reverse transcriptase-polymerase chain reaction (RT-PCR). Results: Integrin alpha(v)beta(3) was expressed in MDA-MB-231 and MDA-MB-435, but not in MKL-4 or T-47D, using both immunohistochemistry and flow cytometry. By RT-PCR, positive bands for both alpha(v) and beta(3) subunits were identified in MDA-MB-231 and 435, while only the alpha(v) subunit mRNA was present in MKL-4 and T-47D. BM was common in vivo following inoculation with MDA-MB-231 or 435, but not with MKL-4. Conclusion: Integrin alpha(v)beta(3) expression appears to play a key role in the development of BM from breast cancer.