| Summary: | 碩士 === 高雄醫學大學 === 醫學研究所碩士班 === 105 === Epidermal growth factor receptor (EGFR), also known as Her1, is a transmembrane receptor including tyrosine kinase domain. EGFR binds with EGF ligands and then activates AKT or ERK signaling, which regulates the cellular proliferation, differentiation and mobility. EGFR overexpresses in a variety of human cancers, including breast cancer, stomach cancer, lung cancer and bladder cancer [1, 2].
EGFR consists of an extracellular domain for ligand binding, a transmembrane domain for transferring signal, and a intracellular tyrosine kinase domain. The receptor tyrosine kinase (RTK) binding with ATP causes kinase auto-phosphorylation leading to some cellular effects, like division, growth and death. EGFR overexpression as playing an important role in cancer progress has been reported in non-small cell lung cancers (NSCLC). Some RTK inhibitors against ATP binding sites (ABS) have been commercially available for NSCLC, like Gefitinib (Iressa), Erlotinib (Tarceva), AEE788, HKI-272 and so on. [3]. However, it is well-known that long-term drug use may give rise to drug resistance in NSCLC. Previous studies showed that a mutant-ABS RTK on cancer cells may confer resistance to chemotherapeutic agents, thus reducing drug efficacy [4-6]. Therefore, new agents for the mutant-ABS RTK are needed.
In this study, we aim to efficiently get a new chemical agent for such mutated NSCLC cells by virtual drug screening of molecular docking. One innovated step to avoid the bad quality of X-ray crystals, a dock-back strategy was taken to select the best binding sites among all the mutant-ABS RTK crystals. Such approach indicates that three RTK crystals, 3W33, 3W2R, 2ITQ, exhibited the dockable ATP binding sites in our view for virtual screening. After screening through the chemical database library, Maybidge, 30 hits were qualified and identified by the evaluation of consensus scoring. In biological validation, the ATP consumption assay showed that, among the 17 hits of 3W33 and 3W2R, 5 compounds could inhibit A549 and NCI-H1975 cell proliferation. Western blot confirmed that, among 7 hits of 3W2R, 1 to 2 compounds could interrupted the auto-phosphorylation of RTK in NCI-H1975.
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