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Selumetinib overcomes gefitinib primary and acquired resistance by regulating MIG6/STAT3 in NSCLC
Xiaoping Song1,2, Lina Wang1,2, Wei Tang3
1Department of Pharmaceutical Engineering, School of Chemical Engineering, Northwest University, 229 Taibai North Road, Xi'an, 710069, China.
Abstract:
Gefitinib, as the first-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), has achieved great advances in the treatment of non-small cell lung cancer (NSCLC), but drug resistance will inevitably occur. Therefore, exploring the resistance mechanism of gefitinib and developing new combination treatment strategies are of great importance. In our study, the results showed that selumetinib (AZD6244) synergistically inhibited the proliferation of NSCLC with gefitinib. Selumetinib also enhanced gefitinib-induced apoptosis and migration inhibition ability in gefitinib-resistant lung cancer cell lines. Subsequently, the negative regulation between MIG6 and STAT3 was observed and verified through the STRING database and western blotting assays. Sustained activation of STAT3 was significantly downregulated when co-treatment with selumetinib in gefitinib-resistant cells. However, the downregulation of p-STAT3, resulting from the combination of selumetinib and gefitinib was counteracted by the deletion of MIG6, suggesting that selumetinib enhanced gefitinib sensitivity by regulating MIG6/STAT3 in NSCLC. In contrast, p-STAT3 was further inhibited after treatment with gefitinib and selumetinib when MIG6 was overexpressed. Furthermore, the combined administration of selumetinib and gefitinib effectively promoted the sensitivity of lung cancer xenografts to gefitinib in vivo, and the tumor inhibition rate reached 81.49%, while the tumor inhibition rate of the gefitinib monotherapy group was only 31.95%. Overall, MIG6/STAT3 negative regulation plays an important role in the sustained activation of STAT3 and the resistance to EGFR-TKIs. Our study also suggests that EGFR-TKIs combined with MEK1/2 inhibitors, such as selumetinib, may be beneficial to those NSCLC patients who develop a primary or acquired resistance to EGFR-TKIs, providing theoretical support for combining TKIs and selumetinib in clinical cancer treatment.
Insights
Combining gefitinib with selumetinib overcomes drug resistance in non-small cell lung cancer (NSCLC) by targeting the MIG6/STAT3 pathway. This combination therapy enhances apoptosis and tumor inhibition, offering new hope for NSCLC patients.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is vital for non-small cell lung cancer (NSCLC) treatment.
- Acquired resistance to gefitinib limits its long-term efficacy, necessitating research into resistance mechanisms and novel therapeutic strategies.
Purpose of the Study:
- To investigate the synergistic effects of selumetinib (a MEK1/2 inhibitor) with gefitinib in NSCLC.
- To elucidate the underlying molecular mechanisms, focusing on the MIG6/STAT3 pathway, involved in gefitinib resistance.
Main Methods:
- In vitro studies using gefitinib-resistant NSCLC cell lines to assess proliferation, apoptosis, and migration.
- Western blotting and STRING database analysis to investigate the interaction between MIG6 and STAT3.
- In vivo studies using lung cancer xenografts in mice to evaluate the efficacy of combined gefitinib and selumetinib treatment.
Main Results:
- Selumetinib synergized with gefitinib to inhibit NSCLC proliferation and enhance apoptosis and migration inhibition in resistant cells.
- The combination therapy downregulated sustained STAT3 activation by regulating the negative feedback loop between MIG6 and STAT3.
- In vivo, combined gefitinib and selumetinib achieved an 81.49% tumor inhibition rate, significantly higher than gefitinib monotherapy (31.95%).
Conclusions:
- The MIG6/STAT3 pathway is crucial in mediating STAT3 activation and resistance to EGFR-TKIs in NSCLC.
- Combining EGFR-TKIs like gefitinib with MEK1/2 inhibitors such as selumetinib shows promise for overcoming primary or acquired resistance in NSCLC patients.
- This study provides a strong theoretical basis for the clinical application of combination therapies involving TKIs and selumetinib.
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