Related Experiment Video
Updated: Mar 25, 2026
Establishing Dual Resistance to EGFR-TKI and MET-TKI in Lung Adenocarcinoma Cells In Vitro with a 2-step Dose-escalation Procedure
Published on: August 11, 2017
Cigarette smoke extract exposure induces EGFR-TKI resistance in EGFR-mutated NSCLC via mediating Src activation and
Dandan Li1, Lu Zhang1, Junhao Zhou2
1Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China.
Objectives:
The study aims to explore the molecular basis for the poor response of epithelial growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in EGFR mutated non-small cell lung cancer (NSCLC) patients with smoking history. Novel agent overcoming EGFR-TKI resistance had also been investigated.
Methods:
The impact of cigarette smoke extract (CSE) on gefitinib sensitive PC-9 cells was evaluated using quantitative real-time PCR (qRT-PCR), western blot, CCK-8 assays, immunofluorescence staining, matrigel invasion assays and wound healing assays.
Results:
Western blot and qRT-PCR presented that CSE stimulated the up-regulation of Vimentin and down-regulation of E-cadherin in PC-9 cells in concentration-and time-dependent manners through modulating Src phosphorylation. N-acetylcysteine (NAC) was capable of decreasing Src phosphorylation, abrogating changes of epithelial to mesenchymal transition (EMT) markers instigated by CSE. Immunofluorescence staining found that PC-9 cells displayed features of mesenchymal cells after CSE exposure, while PP2 and NAC could recover these changes. CCK-8 assays showed that CSE could increase the IC50 of PC-9 cells, while PP2 and NAC could abort the elevation of IC50 caused by CSE. Matrigel invasion assays and wound healing assays showed that CSE could increase the invasion and migration ability of PC-9 cells, which could be suppressed by NAC and PP2.
Conclusion:
CSE exposure induced EGFR-TKI resistance via mediating Src activation and EMT in NSCLC. NAC may alleviate smoking induced EGFR-TKI resistance through inhibiting Src activation and EMT reversal. NAC may be a promising adjuvant to reinforce the effect of EGFR-TKI.
Insights
Cigarette smoke extract (CSE) induces resistance to epithelial growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in non-small cell lung cancer (NSCLC) by activating Src and promoting epithelial-mesenchymal transition (EMT). N-acetylcysteine (NAC) may reverse this resistance.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Smoking is a significant risk factor for non-small cell lung cancer (NSCLC) and is associated with poor response to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs).
- The molecular mechanisms underlying EGFR-TKI resistance in smokers with EGFR-mutated NSCLC remain incompletely understood.
Purpose of the Study:
- To investigate the molecular basis of EGFR-TKI resistance in EGFR-mutated NSCLC patients with a smoking history.
- To explore novel agents that can overcome EGFR-TKI resistance.
Main Methods:
- Quantitative real-time PCR (qRT-PCR) and Western blot to assess gene and protein expression.
- Cell Counting Kit-8 (CCK-8) assays to evaluate cell viability.
- Immunofluorescence staining, matrigel invasion, and wound healing assays to analyze cell morphology, invasion, and migration.
- Exposure of gefitinib-sensitive PC-9 cells to cigarette smoke extract (CSE) and treatment with N-acetylcysteine (NAC) or PP2 (a Src inhibitor).
Main Results:
- CSE exposure led to increased Vimentin and decreased E-cadherin expression in PC-9 cells, indicative of epithelial-mesenchymal transition (EMT), mediated by Src phosphorylation.
- CSE increased gefitinib's IC50, cell invasion, and migration, while NAC and PP2 reversed these effects.
- NAC decreased Src phosphorylation and abrogated CSE-induced EMT markers and mesenchymal cell morphology.
Conclusions:
- CSE induces EGFR-TKI resistance in NSCLC by activating Src and promoting EMT.
- NAC demonstrates potential in alleviating smoking-induced EGFR-TKI resistance by inhibiting Src activation and reversing EMT.
- NAC may serve as a promising adjuvant therapy to enhance the efficacy of EGFR-TKIs in NSCLC patients who smoke.
More Related Videos
06:12Using Nicotine in a Silica-Exposed Mouse Model to Promote Lung Epithelial-Mesenchymal Transition
Published on: March 3, 2023
13:34A Combined 3D Tissue Engineered In Vitro/In Silico Lung Tumor Model for Predicting Drug Effectiveness in Specific Mutational Backgrounds
Published on: April 6, 2016
Related Concept Videos
02:38Mitogens and the Cell Cycle
02:30Metastasis
Epithelial-to-Mesenchymal Transition
The epithelial-to-mesenchymal transition or EMT is a developmental process commonly observed in wound healing, embryogenesis, and cancer metastasis. EMT is induced by transforming growth factor-beta (TGF-β) or receptor tyrosine kinase (RTK) ligands, which further...