Abstract
Our recent study showed that a novel member of bone morphogenetic protein (BMP) family, BMP-10, was decreased in prostate cancer. In the present study, we investigated the implication of BMP-10 in breast cancer, particularly the relation of its expression with clinical aspects. The expression of BMP-10 was examined in a cohort of human breast cancer specimens (normal, n = 23; cancer, n = 97), using both quantitative real-time PCR and immunohistochemical staining. The full-length human BMP-10 was cloned into a mammalian expression plasmid vector and then transfected into breast cancer cells. The effect on growth, cell matrix adhesion, motility, and invasion of MDA-MB-231 cells by BMP-10 was then investigated using in vitro growth assays. Immunohistochemical staining and quantitative real-time PCR revealed a decreased expression of BMP-10 in breast cancer. Further analysis of BMP-10 transcript level against the clinical aspect demonstrated that the decreased BMP-10 expression correlated with disease progression, bone metastasis, and poor prognosis. The disease-free survival of the patients with a higher level of BMP-10 was 132.8 (95% CI, 122.0-143.5) months, significantly longer compared to 93.7 (95% CI, 60.3-127.2) months for patients with a lower level of BMP-10 expression (P = 0.043). The overexpression of BMP-10 has broad inhibitory effects on the in vitro growth, invasion, and motility of breast cancer cells. Taken together, BMP-10 can inhibit the cell growth of breast cancer cells, and decreased BMP-10 expression correlates to poor prognosis and disease progression, particularly the lymphatic and bone metastasis. Bone morphogenetic protein-10 (BMP-10) may function as a tumor suppressor in breast cancer.