Discovery of potent antiproliferative agents from selected oxygen heterocycles as EGFR tyrosine kinase inhibitors from the U.S. National Cancer Institute database by in silico screening and bioactivity evaluation

A similarity search was conducted on the U.S. Enhanced National Cancer Institute Database Browser 2.2 to find structures related to 1,5-dihydroxy-9H-xanthen-9-one, a previously established EGFR-TK inhibitor. Compounds were virtually screened and selected for bioactivity testing revealed 5 candidates, mostly displayed stronger antiproliferative activities than erlotinib with IC₅₀ values between 0.95 and 17.71 μM against overexpressed EGFR-TK cancer cell lines: A431 and HeLa. NSC107228 displayed the strongest antiproliferative effects with IC₅₀ values of 2.84 and 0.95 μM against A431 and HeLa cancer cell lines, respectively. Three compounds, NSC81111, NSC381467 and NSC114126 inhibited EGFR-TK with IC₅₀ values between 0.15 and 30.18 nM. NSC81111 was the best inhibitor with IC₅₀ = 0.15 nM. Molecular docking analysis of the 3 compounds predicted hydrogen bonding and hydrophobic interactions with key residues were important for the bioactivities observed. Furthermore, calculations of the physicochemical properties suggest the compounds are drug-like and are potentially active orally.