Cancer-associated fibroblasts affect breast cancer cell gene expression, invasion and angiogenesis.

Purpose: It has been reported that stromal cell features may affect the clinical outcome of breast cancer patients. Cancer associated fibroblasts (CAFs) represent one of the most abundant cell types within the breast cancer stroma. Here, we aimed to explore the influence of CAFs on breast cancer gene expression, as well as on invasion and angiogenesis.

Methods: qRT-PCR was used to evaluate the expression of several cancer progression related genes (S100A4, TGFβ, FGF2, FGF7, PDGFA, PDGFB, VEGFA, IL-6, IL-8, uPA, MMP2, MMP9, MMP11 and TIMP1) in the human breast cancer-derived cell lines MCF-7 and MDA-MB-231, before and after co-culture with CAFs. Stromal mononuclear inflammatory cell (MIC) MMP11 expression was used to stratify primary tumors. In addition, we assessed the in vitro effects of CAFs on both MDA-MB-231 breast cancer cell invasion and endothelial cell (HUVEC) tube formation.

Results: We found that the expression levels of most of the genes tested were significantly increased in both breast cancer-derived cell lines after co-culture with CAFs from either MMP11+ or MMP11- MIC tumors. IL-6 and IL-8 showed an increased expression in both cancer-derived cell lines after co-culture with CAFs from MMP11+ MIC tumors. We also found that the invasive and angiogenic capacities of, respectively, MDA-MB-231 and HUVEC cells were increased after co-culture with CAFs, especially those from MMP11+ MIC tumors.

Conclusions: Our data indicate that tumor-derived CAFs can induce up-regulation of genes involved in breast cancer progression. Our data additionally indicate that CAFs, especially those derived from MMP11+ MIC tumors, can promote breast cancer cell invasion and angiogenesis.