RESUMO
PURPOSE: Breast cancer cells frequently metastasize to distant organs, including bone. Interactions between breast cancer cells and the bone microenvironment are known to enhance tumor growth and osteolytic damage. Here we investigated whether BMP9 (a secretary protein) may change the bone microenvironment and, by doing so, regulate the cross-talk between breast cancer cells and bone marrow-derived mesenchymal stem cells. METHODS: After establishing a co-culture system composed of MDA-MB-231 breast cancer cells and HS-5 bone marrow-derived mesenchymal stem cells, and exposure of this system to BMP9 conditioned media, we assessed putative changes in migration and invasion capacities of MDA-MB-231 cells and concomitant changes in osteogenic marker expression in HS-5 cells and metastases-related genes in MDA-MB-231 cells. RESULTS: We found that BMP9 can inhibit the migration and invasion of MDA-MB-231 cells, and promote osteogenesis and proliferation of HS-5 cells, in the co-culture system. We also found that the BMP9-induced inhibition of migration and invasion of MDA-MB-231 cells may be caused by a decreased RANK ligand (RANKL) secretion by HS-5 cells, leading to a block in the AKT signaling pathway. CONCLUSIONS: From our data we conclude that BMP9 inhibits the migration and invasion of breast cancer cells, and promotes the osteoblastic differentiation and proliferation of bone marrow-derived mesenchymal stem cells by regulating cross-talk between these two types of cells through the RANK/RANKL signaling axis.
Assuntos
Neoplasias da Mama/genética , Comunicação Celular/genética , Fatores de Diferenciação de Crescimento/genética , Células-Tronco Mesenquimais/metabolismo , Animais , Western Blotting , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Comunicação Celular/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Técnicas de Cocultura , Meios de Cultivo Condicionados/farmacologia , Feminino , Regulação Neoplásica da Expressão Gênica , Fator 2 de Diferenciação de Crescimento , Fatores de Diferenciação de Crescimento/metabolismo , Células HCT116 , Humanos , Imuno-Histoquímica , Células-Tronco Mesenquimais/citologia , Camundongos Nus , Osteogênese/efeitos dos fármacos , Osteogênese/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ligante RANK/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
Bone morphogenetic protein 9 (BMP9), a member of TGF-ß superfamily, is reported to inhibit the growth and migration of prostate cancer, osteosarcoma and triple-negative MDA-MB-231 breast cancer cells. However, little is known about the effect of on the biological behaviors of HER2-positive SK-BR-3 breast cancer cells and the underlying mechanisms. This study aimed to investigate the effects of BMP9 on the proliferation and metastasis of SK-BR-3 cells with BMP9 over-expression or BMP9 down-regulated expression. Results indicated that exogenously expressed BMP9 inhibited the proliferation and metastasis of SK-BR-3 cells while decreased endogenous BMP9 expression in SK-BR-3 cells promoted the proliferation and migration of breast cancer cells in vitro and in vivo. In SK-BR-3 cells with BMP9 over-expression, the phosphorylation of HER2, ERK1/2 and AKT was markedly suppressed and the HER2 expression decreased at both mRNA and protein levels, while opposite results were observed in SK-BR-3 cells with BMP9 knock down. When the phosphorylation of ERK1/2 and PI3K/AKT was inhibited by PD98059 and LY294002, respectively, the decreased proliferation and invasion induced by BMP9 knock down were eliminated. These findings suggest that BMP9 can inhibit the proliferation and metastasis of SK-BR-3 cells via inactivating ERK1/2 and PI3K/AKT signaling pathways. Thus, BMP9 may serve as a useful agent in the treatment of HER-2 positive breast cancer.
Assuntos
Neoplasias da Mama/genética , Fatores de Diferenciação de Crescimento/genética , Proteína Oncogênica v-akt/genética , Fosfatidilinositol 3-Quinases/genética , Apoptose/genética , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Proliferação de Células/genética , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Fator 2 de Diferenciação de Crescimento , Fatores de Diferenciação de Crescimento/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases/genética , Terapia de Alvo Molecular , Metástase Neoplásica , Proteína Oncogênica v-akt/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , RNA Mensageiro/biossíntese , Receptor ErbB-2/genéticaRESUMO
Bone morphogenetic proteins (BMPs), which belong to the transforming growth factor-ß superfamily, regulate a wide range of cellular responses including cell proliferation, differentiation, adhesion, migration, and apoptosis. BMP9, the latest BMP to be discovered, is reportedly expressed in a variety of human carcinoma cell lines, but the role of BMP9 in breast cancer has not been fully clarified. In a previous study, BMP9 was found to inhibit the growth, migration, and invasiveness of MDA-MB-231 breast cancer cells. In the current study, the effect of BMP9 on the bone metastasis of breast cancer cells was investigated. After absent or low expression of BMP9 was detected in the MDA-MB-231 breast cancer cells and breast non-tumor adjacent tissues using Western blot and immunohistochemistry, In our previous study, BMP9 could inhibit the proliferation and invasiveness of breast cancer cells MDA-MB-231 in vitro and in vivo. This paper shows that BMP9 inhibit the bone metastasis of breast cancer cells by activating the BMP/Smad signaling pathway and downregulating connective tissue growth factor (CTGF); however, when CTGF expression was maintained, the inhibitory effect of BMP9 on the MDA-MB-231 cells was abolished. Together, these observations indicate that BMP9 is an important mediator of breast cancer bone metastasis and a potential therapeutic target for treating this deadly disease.
