Related Experiment Videos
Co-activation of STAT3 and YES-Associated Protein 1 (YAP1) Pathway in EGFR-Mutant NSCLC
Imane Chaib1, Niki Karachaliou2, Sara Pilotto3
1Institut d'Investigació en Ciències Germans Trias i Pujol, Badalona, Spain.
Background:
The efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in EGFR-mutant non-small cell lung cancer (NSCLC) is limited by adaptive activation of cell survival signals. We hypothesized that both signal transducer and activator of transcription 3 (STAT3) and Src-YES-associated protein 1 (YAP1) signaling are dually activated during EGFR TKI treatment to limit therapeutic response.
Methods:
We used MTT and clonogenic assays, immunoblotting, and quantitative polymerase chain reaction to evaluate the efficacy of EGFR TKI alone and in combination with STAT3 and Src inhibition in three EGFR-mutant NSCLC cell lines. The Chou-Talalay method was used for the quantitative determination of drug interaction. We examined tumor growth inhibition in one EGFR-mutant NSCLC xenograft model (n = 4 mice per group). STAT3 and YAP1 expression was evaluated in tumors from 119 EGFR-mutant NSCLC patients (64 in an initial cohort and 55 in a validation cohort) by quantitative polymerase chain reaction. Kaplan-Meier and Cox regression analyses were used to assess the correlation between survival and gene expression. All statistical tests were two-sided.
Results:
We discovered that lung cancer cells survive initial EGFR inhibitor treatment through activation of not only STAT3 but also Src-YAP1 signaling. Cotargeting EGFR, STAT3, and Src was synergistic in two EGFR-mutant NSCLC cell lines with a combination index of 0.59 (95% confidence interval [CI] = 0.54 to 0.63) for the PC-9 and 0.59 (95% CI = 0.54 to 0.63) for the H1975 cell line. High expression of STAT3 or YAP1 predicted worse progression-free survival (hazard ratio [HR] = 3.02, 95% CI = 1.54 to 5.93, P = .001, and HR = 2.57, 95% CI = 1.30 to 5.09, P = .007, respectively) in an initial cohort of 64 EGFR-mutant NSCLC patients treated with firstline EGFR TKIs. Similar results were observed in a validation cohort.
Conclusions:
Our study uncovers a coordinated signaling network centered on both STAT3 and Src-YAP signaling that limits targeted therapy response in lung cancer and identifies an unforeseen rational upfront polytherapy strategy to minimize residual disease and enhance clinical outcomes.
Insights
Targeting both STAT3 and Src-YAP signaling alongside EGFR inhibitors can overcome resistance in EGFR-mutant non-small cell lung cancer (NSCLC). This combination therapy shows promise for improving patient outcomes by minimizing residual disease.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Therapeutics
Background:
- Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) efficacy in EGFR-mutant non-small cell lung cancer (NSCLC) is hampered by adaptive cell survival signals.
- Signal transducer and activator of transcription 3 (STAT3) and Src-YES-associated protein 1 (YAP1) signaling are hypothesized to be dually activated, limiting therapeutic response during EGFR TKI treatment.
Purpose of the Study:
- To investigate the role of STAT3 and YAP1 signaling in EGFR TKI resistance in NSCLC.
- To evaluate the synergistic efficacy of combining EGFR TKIs with STAT3 and Src inhibition.
Main Methods:
- Utilized MTT and clonogenic assays, immunoblotting, and quantitative PCR to assess drug efficacy in EGFR-mutant NSCLC cell lines.
- Employed the Chou-Talalay method for drug interaction analysis and xenograft models for tumor growth inhibition studies.
- Analyzed STAT3 and YAP1 expression in patient tumors and correlated with survival using Kaplan-Meier and Cox regression.
Main Results:
- Lung cancer cells activate STAT3 and Src-YAP1 signaling to survive EGFR inhibitor treatment.
- Co-targeting EGFR, STAT3, and Src demonstrated synergistic effects in EGFR-mutant NSCLC cell lines.
- High STAT3 or YAP1 expression correlated with worse progression-free survival in patients treated with first-line EGFR TKIs.
Conclusions:
- A coordinated signaling network involving STAT3 and Src-YAP limits targeted therapy response in lung cancer.
- Identified a rational upfront polytherapy strategy combining EGFR, STAT3, and Src inhibition to improve clinical outcomes and minimize residual disease.