Triple-negative breast cancer (TNBC), which is tested negative for estrogen receptor,progesterone receptor and HER2/neu receptor, is an aggressive histological subtype of breastcancer with limited choice of treatments. Epidermal growth factor receptor (EGFR) tyrosinekinase inhibitors (TKIs) have been studied to inhibit proliferation of TBNC, however, theylacked efficacy in clinical treatment. This may be due to cross-talk between cancer cells andneighboring stromal cells. For example, hepatocyte growth factor (HGF) secreted bycancer-associated fibroblasts has been shown to bind to a Met receptor and reduce efficiencyof TKIs in TNBC, indicating that microenvironment affected development of cancer cells. Tosurvey the effective TNBC inhibitors, we established a soft agar colony formation system forbreast cancer MDA-MB-468 cells with co-culture of fibroblasts. Neosartorya fischeri extractswere tested for their inhibitory activity on TNBC by applying to this system. The resultsshowed that some secondary metabolites of Neosartorya fischeri inhibitedfibroblast-mediated colony formation of MDA-MB-468 cells. One of these metabolitesexhibited inhibitory effect on phosphorylation of EGFR and Met, which offered the potentialas a chemotherapeutic agent for TNBC.
