Acquisition of epithelial-mesenchymal transition phenotype in the tamoxifen-resistant breast cancer cell: a new role for G protein-coupled estrogen receptor in mediating tamoxifen resistance through cancer-associated fibroblast-derived fibronectin and β1-integrin signaling pathway in tumor cells.
MENA(INV) and FN levels were correlated in two breast cancer cohorts, and high levels of MENA(INV) were significantly associated with increased tumor recurrence as well as decreased patient survival.
Using this breast cancer (BC) model, we find that in addition to EGF, adhesion to fibronectin (FN) activates signal transducer and activator of transcription 3 (STAT3) through EGFR-dependent and -independent mechanisms.
Expression of fibronectin 1 gene induced by rtEa4-peptide in MDA-MB-231 cells was abolished by inhibitors of PI3K, PKC, Mek1/2, JNK1/2, and p38 MAPK signaling transduction molecules.
RNA interference of endogenous PTHrP caused a significant reduction in cell adhesion of a breast cancer cell line to collagen type I, fibronectin and laminin (P<0.05) and of a colon cancer cell to collagen type I and fibronectin (P<0.05).
We demonstrate that conditioned medium from ASCs induces breast cancer cells (4T1) to express mesenchymal markers such as fibronectin, alpha smooth muscle actin and vimentin.
Subsequently, a large panel of breast cancer cell lines was used to validate that hypoxia induces the expression of integrins that bind to collagen (ITGA1, ITGA11, ITGB1) and fibronectin (ITGA5, ITGB1).
Previous studies have shown that FN can be degraded into fragments by MMP-9 in vitro; MMP-9 expression is upregulated in breast cancer, therefore, the role of degraded FN in breast cancer progression needs to be investigated.
In this study, we report that mda-9/syntenin mediates adhesion-mediated activation of protein kinase Calpha (PKCalpha) and focal adhesion kinase (FAK) by fibronectin (FN) in human breast cancer and melanoma cells.