Browsing by Author "Yen, Kuei-Jung"

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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
;
Song, Jen-Shin
;
Lien, Tzu-Wen
;
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.
Discovery of M Protease Inhibitors Encoded by SARS-CoV-2
(2020-09-01)
Hung, Hui-Chen
;
Ke, Yi-Yu
;
Huang, Sheng Yu
;
Huang, Peng-Nien
;
Kung, Yu-An
The coronavirus (CoV) disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome CoV-2 (SARS-CoV-2) is a health threat worldwide. Viral main protease (M-pro, also called 3C-like protease [3CL(pro)]) is a therapeutic target for drug discovery. Herein, we report that GC376, a broad-spectrum inhibitor targeting M-pro in the picornavirus-like supercluster, is a potent inhibitor for the M-pro encoded by SARS-CoV-2, with a half-maximum inhibitory concentration (IC50) of 26.4 +/- 1.1 nM. In this study, we also show that GC376 inhibits SARS-CoV-2 replication with a half-maximum effective concentration (EC50) of 0.91 +/- 0.03 mu M. Only a small portion of SARS-CoV-2 M-pro was covalently modified in the excess of GC376 as evaluated by mass spectrometry analysis, indicating that improved inhibitors are needed. Subsequently, molecular docking analysis revealed that the recognition and binding groups of GC376 within the active site of SARS-CoV-2 M-pro provide important new information for the optimization of GC376. Given that sufficient safety and efficacy data are available for GC376 as an investigational veterinary drug, expedited development of GC376, or its optimized analogues, for treatment of SARS-CoV-2 infection in human is recommended.
Evaluation of the Antitumor Effects of BPR1J-340, a Potent and Selective FLT3 Inhibitor, Alone or in Combination with an HDAC Inhibitor, Vorinostat, in AML Cancer
(2014-01-08)
Lin, Wen-Hsing
;
Yeh, Teng-Kuang
;
Jiaang, Weir-Torn
;
Yen, Kuei-Jung
;
Chen, Chun-Hwa
Overexpression or/and activating mutation of FLT3 kinase play a major driving role in the pathogenesis of acute myeloid leukemia (AML). Hence, pharmacologic inhibitors of FLT3 are of therapeutic potential for AML treatment. In this study, BPR1J-340 was identified as a novel potent FLT3 inhibitor by biochemical kinase activity (IC50 approximately 25 nM) and cellular proliferation (GC(50) approximately 5 nM) assays. BPR1J-340 inhibited the phosphorylation of FLT3 and STAT5 and triggered apoptosis in FLT3-ITD+ AML cells. The pharmacokinetic parameters of BPR1J-340 in rats were determined. BPR1J-340 also demonstrated pronounced tumor growth inhibition and regression in FLT3-ITD+ AML murine xenograft models. The combination treatment of the HDAC inhibitor vorinostat (SAHA) with BPR1J-340 synergistically induced apoptosis via Mcl-1 down-regulation in MOLM-13 AML cells, indicating that the combination of selective FLT3 kinase inhibitors and HDAC inhibitors could exhibit clinical benefit in AML therapy. Our results suggest that BPR1J-340 may be further developed in the preclinical and clinical studies as therapeutics in AML treatments.
Inhibition of enterovirus 71 replication and the viral 3D polymerase by aurintricarboxylic acid
(2010-04-01)
Hung, Hui-Chen
;
Chen, Tzu-Chun
;
Fang, Ming-Yu
;
Yen, Kuei-Jung
;
Shih, Shin-Ru
Enterovirus 71 (EV71) causes serious diseases in humans. The aim of this study was to examine the effects of aurintricarboxylic acid (ATA) on EV71 replication and to explore the underlying mechanism. To measure the activity of ATA in inhibiting the cytopathic effect (CPE) of EV71, a cell-based neutralization (inhibition of virus-induced CPE) assay was performed. The effect of ATA was further confirmed using plaque reduction and viral yield reduction assays. A time of addition assay was performed to identify the mechanisms of ATA's anti-EV71 activity. We examined the effects of ATA on the following key steps involved in virus replication: (i) translation of the internal ribosomal entry site (IRES)-mediated viral polyprotein; (ii) the proteolytic activity of viral proteases 2A and/or 3C; and (iii) the viral 3D RNA-dependent RNA polymerase (RdRp) activity. In this study, ATA was found to be a potent inhibitor of the replication of EV71. In the antiviral neutralization assay, ATA exhibited inhibitory activity against EV71 (TW/4643/98) and EV71 (TW/2231/98). Plaque assay further demonstrated that ATA inhibited EV71 replication with an EC(50) (effective concentration at which 50% of plaques were removed) of 2.9 mu M. Studies on the mechanism of action revealed that ATA targets the early stage of the viral life cycle after viral entry. ATA was able to inhibit the RdRp activity of EV71, while neither the IRES-mediated translation of viral polyprotein nor the viral 3C protease activity was affected. Overall, the findings in this study suggest that ATA is able to effectively inhibit EV71 replication through interfering with the viral 3D polymerase.
Suppression of Stat3 activity sensitizes gefitinib-resistant non small cell lung cancer cells
(2011-06-01)
Chiu, Huan-Chih
;
Chou, Ding-Li
;
Huang, Chin-Ting
;
Lin, Wen-Hsing
;
Lien, Tzu-Wen
Epidermal growth factor receptor (EGFR) is a proven therapeutic target to treat a small subset of non small cell lung cancer (NSCLC) harboring activating mutations within the EGFR gene. However, many NSCLC patients are not sensitive to EGFR inhibitors, suggesting that other factors are implicated in survival of NSCLC cells. Signal transducers and activators of transcription 3 (Stat3) function as transcription factor to mediate cell survival and differentiation and the dysregulation of Stat3 has been discovered in a number of cancers. In this study, we found that a small molecule, reactivation of p53 and induction of tumor cell apoptosis (RITA), showed anti-cancer activity against gefitinib-resistant H1650 cells through a p53-independent pathway. Stat3 suppression by RITA attracted our attention to investigate the role of Stat3 in sustaining survival of H1650 cells. Pharmacological and genetic approaches were employed to down-regulate Stat3 in H1650 cells. WP1066, a known Stat3 inhibitor, was shown to exhibit inhibitory effect on the growth of H1650 cells. Meanwhile, apoptosis activation by siRNA-mediated down-regulation of Stat3 in H1650 cells provides more direct evidence for the involvement of Stat3 in viability maintenance of H1650 cells. Moreover, as a novel identified Stat3 inhibitor, RITA increased doxorubicin sensitivity of H1650 cells in vitro and in vivo, suggesting that doxorubicin accompanied with Stat3 inhibitors may be considered as an alternative strategy to treat NSCLC patients who have inherent resistance to doxorubicin. Overall, our observations reveal that targeting Stat3 may be an effective treatment for certain NSCLC cells with oncogenic addition to Stat3. (C) 2011 Elsevier Inc. All rights reserved.