Study of the mechanisms of emetine dihydrochloride on inhibiting NSCLC tumor progression and attenuating EGFR signaling pathway
| Autor: | Wan-Ting Huang, 黃琬婷 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 Epidermal growth factor receptor (EGFR) is a transmembrane receptor protein, mediated cellular biological response from diverse environmental signals binding to and activating intracellular tyrosine kinases domains, including regulation of cellular proliferation, differentiation, migration and survival. More than 60 % of non-small cell Lung cancers (NSCLCs) express EGFR, and EGFR has become an important therapeutic target for the treatment of these tumors. Tyrosine kinase inhibitors (TKIs) is a pharmaceutical drug that inhibits tyrosine kinases by competing with adenosine triphosphate (ATP), or can act in an allosteric site, affecting its activity by a conformational change. Despite the efficacy of EGFR-targeted therapy in advanced NSCLC, almost all patients ultimately develop resistance to these agents. The most common secondary mutation is found to harbor EGFR mutations in T790M, which are acquired resistance to EGFR TKIs. In order to overcames the T790M mutation in lung cancer, Enzyme-linked Immunosorbent assay (ELISA) was used to select candidate compounds which may be supuress EGFR activity. First, EGFR pY1068 ELISA as drug-screening platform to screen compound library of more than 300 plant active ingredients. Among of these compounds, emetine could most significantly suppress EGFR activity in EGFR mutant cell line H1975. Emetine is a natural compound originated from ipecac roots. It was commonly used as anti-protozoal and vomiting agent. The apoptosis-inducing effect of emetine makes it considered as a potential anti-cancer agent for various human cancers. We found that Prestoblue® assay analysis showed emetine harbored dose-dependent suppression of cell viability in three different EGFR genotype NSCLC cell line. Moreover, emetine was effectively reduce the EGFR pY1068 phosphorylation and protein expression in a dose-dependent manner, as well as reduce STAT3 and Src activity both in H1975 and H3255 cells. However, the treatment of emetine in EGFR wild type A549 cells does not significantly affect the EGFR phosphorylation. Surprisingly, STAT3 and Src activity is significantly blocked by emetine in A549 cells. Furthermore, most of the EGFR downstream and Src-related signaling pathway is blocked by emetine treatment in A549, H3255 and H1975 cells. Emetine inhibits cell proliferation, migration, invasion, and colony formation abilities in gefitinib-resistant lung adenocarcinoma cells and xenografts tumor growth in SCID mice. Taken together, we have shown that emetine is a novel inhibitory modulator of EGFR activity and is effective in inhibiting the tumor growth of EGFR-TKI-resistant NSCLC cells. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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