Browsing by Author "Hsu, John T-A"

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A High-throughput Cell-based Screening for L858R/T790M Mutant Epidermal Growth Factor Receptor Inhibitors
(2012-01-01)
Lin, Wen-Hsing
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Song, Jen-Shin
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Lien, Tzu-Wen
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Chang, Chun-Yu
;
Wu, Szu-Huei
A high-throughput 32D(L858R/T790M) cell-based assay to identify inhibitors of the L858R/T790M mutant epidermal growth factor receptor (EGFR) pathway was established. After screening, ten hits from among 60,000 compounds in our in-house compound library were initially identified. In the secondary assays, one hit, 1-[2-(decyloxy)-2-oxoethyl]-3-methyl-2-[(4-methylphenoxy) methyl]-1H-benzimidazol-3-ium, was confirmed to directly inhibit the kinase activity of recombinant L858R/T790M EGFR and the phosphorylation of EGFR-L858R/T790M in gefitinib-resistant H1975 cells. Thus, this high-throughput assay system may be useful for identifying novel inhibitors which suppress mutant EGFR-T790M signalling and for overcoming T790M-mediated acquired resistance for future anticancer drug discovery.
Identification, SAR Studies, and X-ray Co-crystallographic Analysis of a Novel Furanopyrimidine Aurora Kinase A Inhibitor
(2010-02-01)
Coumar, Mohane Selvaraj
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Tsai, Ming-Tsung
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Chu, Chang-Ying
;
Uang, Biing-Jiun
;
Lin, Wen-Hsing
Here in we reveal a simple method for the identification of novel Aurora kinase A inhibitors through substructure searching of an in-house compounds for testing. A hydrazone fragment conferring Aurora kinase activity and heterocyclic rings most frequently reported in kinase inhibitors were used as substructure queries to filter the in house compound library collection prior to testing. Five new series of Aurora kinase inhibitors were identified through this strategy with IC(50) values ranging from similar to 300 nm to similar to 15 mu m, by testing only 133 compounds from a database of similar to 125 000 compounds. Structure activity relationship studies and X-ray co-crystallographic analysis of the most potent compound, a furanopyrimidine derivative with an IC(50) value of 309 nm toward Aurora kinase A, were carried out. The knowledge gained through these studies could help in the future design of potent Aurora kinase inhibitors.
Non-small-cell lung cancer cells combat epidermal growth factor receptor tyrosine kinase inhibition through immediate adhesion-related responses
(2016-01-01)
Wang, Hsian-Yu
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Hsu, Min-Kung
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Wang, Kai-Hsuan
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Tseng, Ching-Ping
;
Chen, Feng-Chi
Background: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), such as gefitinib, erlotinib, and afatinib, have greatly improved treatment efficacy in non-small cell lung cancer (NSCLC) patients with drug-sensitive EGFR mutations. However, in some TKI responders, the benefits of such targeted therapies are limited by the rapid development of resistance, and strategies to overcome this resistance are urgently needed. Studies of drug resistance in cancer cells typically involve long term in vitro induction to obtain stably acquired drug-resistant cells followed by elucidation of resistance mechanisms, but the immediate responses of cancer cells upon drug treatment have been ignored. The aim of this study was to investigate the immediate responses of NSCLC cells upon treatment with EGFR TKIs. Results: Both NSCLC cells, ie, PC9 and H1975, showed immediate enhanced adhesion-related responses as an apoptosis-countering mechanism upon first-time TKI treatment. By gene expression and pathway analysis, adhesion-related pathways were enriched in gefitinib-treated PC9 cells. Pathway inhibition by small-hairpin RNAs or small-molecule drugs revealed that within hours of EGFR TKI treatment, NSCLC cells used adhesion-related responses to combat the drugs. Importantly, we show here that the Src family inhibitor, dasatinib, dramatically inhibits cell adhesion-related response and greatly enhances the cell-killing effects of EGFR TKI (gefitinib for the PC9 cells; afatinib for the H1975 cells) in NSCLC cells, which would otherwise escape the TKI-induced apoptosis. Conclusion: Results from this study indicate that NSCLC cells can employ the adhesion response as a survival pathway to survive under EGFR-targeted therapy. Simultaneous targeting of EGFR signaling and adhesion pathways would further boost the efficacy of EGFR-targeted therapy in NSCLC.