Abstract

In our previous work, Ets-1 upregulates human epidermal growth factor receptor 2 (HER2) induced matrix metalloproteinase 1 (MMP-1) expression. Based on the above knowledge and result, we hypothesized that estrogen receptor (ER) and its signaling pathway may affect MMP-1 expression under the influence of HER2. In addition, we investigated how the HER2 pathway cross-talk with the ER signaling pathway in genomic and nongenomic action of ER using reverse transcription-PCR, Western blot analysis, and ELISA assay. The results showed that ER-α expression increased MMP-1 expression under the presence of HER2. These upregulatory effects were mediated mainly by mitogen-activated protein kinase pathway and were reversed by downregulation of HER2 and/or ER. Activator protein DNA binding activity was involved in the MMP-1 expression. In summary, our results showed that ER can upregulate MMP-1 expression under the influence of HER2 in MCF-7 cells. In addition, this upregulatory effect was found to be mediated by mitogen-activated protein kinase pathway. MMP-1 might be an assigned target in interaction between ER and HER2. Mol Cancer Res; 8(7); 1037–47. ©2010 AACR.