Available online xxxKeywords: Caffeic acid derivatives EGFR inhibitor Triple-negative breast cancer Non-small cell lung cancer Molecular modeling Abbreviations: CA, caffeic acid CAPE, caffeic acid phenethyl ester EGFR, epidermal growth factor receptor RTK, receptor tyrosine kinase TNBC, triple-negative breast cancer a b s t r a c t A small molecule EGFR inhibitor, 4-(2-(3-(4-(4-(trifluoromethyl)phenyl)thiazol-2-yl)ureido) vinyl)-1,2-phenylene diacetate (CIU1) was designed in silico by using caffeic scaffold as core structure. The designed compound showed anti-proliferative action against different solid tumor cell lines, particularly metastatic breast cancer cells. CIU1 inhibited the growth of EGFR-overexpressing MDA-MB-468 triple-negative breast cancer cells and wild-type nonsmall-cell lung cancer H460 cells with IC 50 values of 8.96 mM and 12.98 mM, respectively, these anti-proliferative effects of CIU1 were comparable to gefitinib (a specific EGFR inhibitor) or lapatinib (a dual EGFR and HER2 tyrosine kinase inhibitor). Interestingly CIU1 effectively inhibited the invasive hormone-dependent MCF-7 cancer cells with an IC 50 2.34 mM. The immunoblot analyses revealed that CIU1 induced programmed cell death and suppressed EGFR expression in EGFR-overexpressing breast cancer (MDA-MB468) and lung cancer (PC-9) cells. The findings substantiated our design strategy and demonstrated the potential of CIU1 as new lead for further optimization in the development of anticancer drugs against advanced solid tumors.