Project description:This SuperSeries is composed of the following subset Series: GSE31603: Human breast cancer cell lines: vehicle vs. BMP4 incubation GSE31604: Human breast cancer cell lines: vehicle vs. BMP7 incubation Refer to individual Series
Project description:Bone morphogenetic proteins (BMPs) are members of the TGF-β superfamily of growth factors. They are known for their roles in regulation of osteogenesis and developmental processes and, in recent years, evidence has accumulated of their crucial functions in tumor biology. BMP4, in particular, has been implicated in breast cancer. However, little is known about BMP target genes in the context of tumor. We therefore explored the effects of BMP4 treatment on global gene transcription in five breast cancer cell lines during a 6-point time series. Data analysis included hierarchical clustering of differentially expressed genes, gene ontology enrichment analyses and model based clustering of temporal data. BMP4 had a strong effect on gene expression. The cellular functions most strongly affected were regulation of transcription and development. The observed transcriptional response, as well as its functional outcome, followed a temporal sequence, with regulation of gene expression and signal transduction leading to changes in metabolism and cell proliferation. Hierarchical clustering revealed distinct differences in the response of individual cell lines to BMP4, but also highlighted a synexpression group of genes. Finally, this study provides a list of potential novel BMP target genes relevant in breast cancer. Two-condition experiment, vehicle-treated vs. BMP4-treated. Five cell lines were tested at six time points each, what makes a total of 30 samples. RNA samples from three biological replicates were pooled before hybridization.
Project description:Bone morphogenetic protein 4 (BMP4) is a remarkably powerful inhibitor of breast cancer cell proliferation, but is also able to induce breast cancer cell migration in certain cellular contexts. Previous data demonstrate that BMP4 controls the transcription of a variety of protein coding genes, but not much is known about microRNAs (miRNA) regulated by BMP4. In this study, miRNA expression patterns following BMP4 treatment were determined in one mammary epithelial and seven breast cancer cell lines using microarrays. The analysis identified 20 to 128 differentially expressed miRNAs in individual cell lines with emphasis on upregulation over downregulation. Four miRNAs (miR-16-5p, miR-106b-5p, miR-23a-3p and miR-23b-3p) were commonly induced in a subset of breast cancer cells upon BMP4 treatment and inhibition of their expression resulted in an increase in BT-474 cell number, indicating that they possess tumor suppressive properties. Yet no major change was detected when the cells were simultaneously treated with BMP4, and thus these miRNAs do not act as the main mediators of BMP4-induced growth reduction. MiR-16-5p and miR-106b-5p were elevated in MDA-MB-231 cells that respond to BMP4 with increased migration. Their inhibition, in combination with BMP4 treatment, resulted in enhanced MDA-MB-231 cell migration, suggesting that miR-16-5p and miR-106b-5p are engaged in BMP4-induced motility. Taken together, we have shown for the first time that in breast cancer cells BMP4 induces variable miRNA expression patterns.
Project description:BMP4 is down-regulated in metastatic human and murine mammary tumours. Here we determined the effect of ectopic mouse Bmp4 re-expression on global gene expression patterns in orthotopic primary mammary tumours in syngeneic Balb/c mice. Breast cancer is a major cause of cancer related death in women, due to the development of metastatic disease in vital organs. Metastasis can be facilitated by tumor induced MDSC, which requires understanding. We have confirmed that BMP4 is a potent suppressor of breast cancer metastasis, but for potential clinical application, it is important to understand how BMP4 acts to suppress metastasis. Here, we report one mechanism by which BMP4 can inhibit metastasis. Mice bearing highly metastatic mammary tumors present with elevated numbers of myeloid derived suppressor cells (MDSC), the extent of which is markedly reduced upon exogenous BMP4 expression. Increased numbers of MDSC can also be induced directly by treatment with granulocyte-colony stimulating factor (G-CSF), leading to enhancement of metastasis. Both tumor-induced and G-CSF-induced MDSC can effectively suppress T cell activation and proliferation. BMP4 acts to reduce the expression and secretion of G-CSF through inhibition of NFkB activity in several human and mouse tumor lines. Since MDSC in breast cancer patients are correlated with poor prognosis, BMP4 treatment offers a potential new therapeutic strategy for progressive breast disease. Three 4T1.2 primary mammary tumours and three 4T1.2-Bmp4 primary mammary tumours were analyzed.