TY - JOUR
T1 - Mammary epithelial cell interactions with fibronectin stimulate epithelial-mesenchymal transition
AU - Park, J.
AU - Schwarzbauer, J. E.
N1 - Funding Information:
We thank Jina Hong for assistance with some experiments. We thank Dr Keith Johnson (University of Nebraska Medical Center) for generously providing N-cadherin antibody. This work was supported by grants from the NIH (R01 GM059383 and R01 CA160611 to JES). JP received support from a Ruth L Kirschstein National Research Service Award (T32 CA 009528).
PY - 2014/3/27
Y1 - 2014/3/27
N2 - In the mammary gland, the stromal extracellular matrix (ECM) undergoes dramatic changes during development and in tumorigenesis. For example, normal adult breast tissue is largely devoid of the ECM protein fibronectin (FN) whereas high FN levels have been detected in the stroma of breast tumors. FN is an established marker for epithelial-mesenchymal transition (EMT), which occurs during development and has been linked to cancer. During EMT, epithelial cell adhesion switches from cell-cell contacts to mainly cell-ECM interactions, raising the possibility that FN may have a role in promoting this transition. Using MCF-10A mammary epithelial cells, we show that exposure to exogenous FN induces an EMT response including upregulation of the EMT markers FN, Snail, N-cadherin, vimentin, the matrix metalloprotease MMP2, α-smooth muscle actin and phospho-Smad2, as well as acquisition of cell migratory behavior. FN-induced EMT depends on Src kinase and extracellular signal-regulated kinase/mitogen-activated protein (ERK/MAP) kinase signaling but not on the immediate early gene EGR-1. FN initiates EMT under serum-free conditions; this response is partially reversed by a transforming growth factor (TGF)β-neutralizing antibody, suggesting that FN enhances the effect of endogenous TGFβ. EMT marker expression is upregulated in cells on a fragment of FN containing the integrin-binding domain but not other domains. Differences in gene expression between FN and Matrigel are maintained with addition of a subthreshold level of TGFβ1. Together, these results show that cells interacting with FN are primed to respond to TGFβ. The ability of FN to induce EMT shows an active role for the stromal ECM in this process and supports the notion that the increased levels of FN observed in breast tumors facilitate tumorigenesis.
AB - In the mammary gland, the stromal extracellular matrix (ECM) undergoes dramatic changes during development and in tumorigenesis. For example, normal adult breast tissue is largely devoid of the ECM protein fibronectin (FN) whereas high FN levels have been detected in the stroma of breast tumors. FN is an established marker for epithelial-mesenchymal transition (EMT), which occurs during development and has been linked to cancer. During EMT, epithelial cell adhesion switches from cell-cell contacts to mainly cell-ECM interactions, raising the possibility that FN may have a role in promoting this transition. Using MCF-10A mammary epithelial cells, we show that exposure to exogenous FN induces an EMT response including upregulation of the EMT markers FN, Snail, N-cadherin, vimentin, the matrix metalloprotease MMP2, α-smooth muscle actin and phospho-Smad2, as well as acquisition of cell migratory behavior. FN-induced EMT depends on Src kinase and extracellular signal-regulated kinase/mitogen-activated protein (ERK/MAP) kinase signaling but not on the immediate early gene EGR-1. FN initiates EMT under serum-free conditions; this response is partially reversed by a transforming growth factor (TGF)β-neutralizing antibody, suggesting that FN enhances the effect of endogenous TGFβ. EMT marker expression is upregulated in cells on a fragment of FN containing the integrin-binding domain but not other domains. Differences in gene expression between FN and Matrigel are maintained with addition of a subthreshold level of TGFβ1. Together, these results show that cells interacting with FN are primed to respond to TGFβ. The ability of FN to induce EMT shows an active role for the stromal ECM in this process and supports the notion that the increased levels of FN observed in breast tumors facilitate tumorigenesis.
KW - Breast cancer
KW - EMT
KW - Fibronectin
KW - MCF-10A cells
KW - TGFβ
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U2 - 10.1038/onc.2013.118
DO - 10.1038/onc.2013.118
M3 - Article
C2 - 23624917
AN - SCOPUS:84897994426
SN - 0950-9232
VL - 33
SP - 1649
EP - 1657
JO - Oncogene
JF - Oncogene
IS - 13
ER -