Bone Morphogenetic Protein-7 Inhibits EMT-Associated Genes in Breast Cancer
Cellular Physiology and Biochemistry
This is an Open Access article licensed under the terms of the Creative Commons Attribution-NonCommercial 3.0 Unported license (CC BY-NC) (www.karger.com/OA-license), applicable to the online version of the article only. Distribution permitted for non-commercial purposes only. Key Words Bone morphogenetic protein-7 (BMP7) • Breast cancer • Transforming growth factor β 1 (TGFβ1) • Epithelial-mesenchymal transition (EMT) Abstract Background/Aims: Bone morphogenetic protein-7 (BMP7) has been shown
... MP7) has been shown to reduce the severity of injury-induced fibrosis through counteracting the fibrotic effects of transforming growth factor β 1 (TGFβ1). However, this model in the carcinogenesis of breast cancer is unknown. Methods: We analyzed the effects of BMP7 and TGFβ1 on gene transcripts and protein levels of EMT-related factors in breast cancer cells by RT-qPCR and Western blot, respectively. The effects of BMP7 and TGFβ1 on cell invasiveness and migration were evaluated by scratch wound healing assay and transwell cell migration assay. The cell growth was measured by MTT assay. Results: BMP7 did not alter the TGFβ1-stimulated phosphorylation of TGFβ receptor, but significantly inhibited the TGFβ1-activated epithelial-mesenchymal transition (EMT)-related genes in breast cancer cells, resulting in a significant reduction in TGFβ1-triggered cell growth and cell metastasis. Conclusion: Our data suggest that besides being a well-known antagonist for TGFβ1 in fibrosis, BMP7 may also antagonize TGFβ1 in tumorigenesis-associated EMT in breast cancer. Thus, BMP7 may be a promising therapeutic target for treating breast cancer. 1274 Ying/Sun/He: BMP7 Inhibits Breast Cancer Cellular Physiology and Biochemistry Cellular Physiology and Biochemistry only activated its own receptor, without cross-activating the receptor for the other. Thus, in case BMP7 may affect the effect of TGFβ1, it should function through signaling cascades downstream of TGFβ receptor activation, rather than directly through modulation of TGFβ receptor activation. BMP7 inhibits TGFβ1-activated EMT-related genes in breast cancer cells Since activated TGFβ/SMAD2/3 receptor signaling by TGFβ1 has been well known for its role in promoting EMT-regulated tumor growth and invasion, we examined levels of Fig. 1. TGFβ1 and BMP7 activate different receptors in breast cancer cells. (A-C) MCF7 cells were treated with either TGFβ1, or BMP7, or both, or null control. Western blot was done for phosphorylated TGFβ receptor I (pTBR1), phosphorylated BMP receptor I (pBMPR1), and α-tubulin (loading control), shown by representative images (A), and by quantification (B-C). *p<0.05. NS: non-significance. n=5. Statistics: oneway ANOVA with a Bonferoni correction, followed by fisher's exact test for comparison of two groups. Fig. 2. BMP7 inhibits TGFβ1-activated EMT-related genes in breast cancer cells. MCF7 cells were treated with either TGFβ1, or BMP7, or both, or null control. RT-qPCR for key EMT-associated genes ZEB1, ZEB2, Snail1, Snail2, E-cadherin (E-cad), N-cadherin (N-cad), Vimentin and Collagen I. *p<0.05. n=5. Statistics: one-way ANOVA with a Bonferoni correction, followed by fisher's exact test for comparison of two groups. 1275 Ying/Sun/He: BMP7 Inhibits Breast Cancer Cellular Physiology and Biochemistry Cellular Physiology and Biochemistry key EMT-related genes ZEB1, ZEB2, Snail1, Snail2, E-cadherin (E-cad), N-cadherin (N-cad), Vimentin and Collagen I. We found that BMP7 completely abolished TGFβ1-induced activation of ZEB1, ZEB2, Snail1, Snail2, N-cad, Vimentin and Collagen I, and significantly abolished TGFβ1-induced suppression of E-cad (Fig. 2) , suggesting a possible antagonizing effect of BMP7 against TGFβ-mediated EMT in breast cancer cells.