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CircSETD3 mediates acquired resistance to gefitinib in non-small lung cancer cells by FXR1/ECT2 pathway
Chunjie Wen1, Yaji Li1, Yutang Huang1
1Institute of Life Sciences, Chongqing Medical University, Chongqing 400016, China.
Background:
Gefitinib is the first-line treatment for non-small cell lung cancer (NSCLC) harboring EGFR sensitive mutation. However, acquired resistance significantly limits its therapeutic efficacy. CircSETD3 has been reported to promote gefitinib resistance in NSCLC cells, however, its underlying mechanisms have not been fully clarified.
Methods:
The expression of circSETD3 were detected in NSCLC patients who received gefitinib as first-line treatment, including 20 gefitinib-sensitive patients and 20 acquired gefitinib-resistant patients. Cell viability were examined by CCK8 assay. The mRNA and protein levels were detected by qRT-PCR and western blot. Using RNA pull-down assay followed by mass spectrometry to identified proteins that interact with circSETD3. The interaction between circSETD3 and fragile X-related protein-1 (FXR1) were further validated by RNA immunoprecipitation (RIP) and pull-down analysis. Fuorescence in situ hybridization (FISH) and immunofluorescence (IF) assays was used for the identification of sub-location of circSETD3 and FXR1 in cells. The effect of circSETD3 overexpression and knockdown on NSCLC tumor growth to gefitinib sensitivity was detected using the mouse xenograft model.
Results:
CircSETD3 was significantly upregulated in gefitinib-resistant NSCLC cells, and decreased the gefitinib sensitivity in vitro and in vivo. Mechanically, circSETD3 facilitated FXR1 binding to its downstream mRNA target, epithelial cell-transforming sequence 2 (ECT2), promoting ECT2 mRNA decay, which further inhibited cellular apoptosis.
Conclusion:
CircSETD3/FXR1/ECT2 axis plays a critical role in the acquired resistance to gefitinib in NSCLC. Our results highlight the potential of circSETD3 as a biomarker and therapeutic target for NSCLC patients with acquired gefitinib resistance.
Insights
Circular RNA circSETD3 promotes gefitinib resistance in non-small cell lung cancer (NSCLC) by interacting with FXR1 and affecting ECT2 mRNA. This highlights circSETD3 as a potential therapeutic target for NSCLC patients.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Gefitinib is a first-line treatment for EGFR-mutated non-small cell lung cancer (NSCLC).
- Acquired resistance to gefitinib significantly limits its long-term efficacy.
- The role of circSETD3 in gefitinib resistance in NSCLC requires further mechanistic elucidation.
Purpose of the Study:
- To investigate the role of circSETD3 in acquired gefitinib resistance in NSCLC.
- To elucidate the underlying molecular mechanisms by which circSETD3 contributes to gefitinib resistance.
- To evaluate circSETD3 as a potential biomarker and therapeutic target for gefitinib-resistant NSCLC.
Main Methods:
- Detected circSETD3 expression in gefitinib-sensitive and resistant NSCLC patients.
- Assessed cell viability, mRNA, and protein levels using CCK8, qRT-PCR, and western blot.
- Identified circSETD3-interacting proteins via RNA pull-down and mass spectrometry, validating FXR1 interaction using RIP and pull-down assays.
- Utilized FISH, IF, and mouse xenograft models to determine circSETD3's sub-cellular localization and its effect on gefitinib sensitivity in vivo.
Main Results:
- CircSETD3 expression was significantly upregulated in gefitinib-resistant NSCLC cells.
- CircSETD3 overexpression decreased gefitinib sensitivity both in vitro and in vivo.
- Mechanistically, circSETD3 facilitated FXR1 binding to ECT2 mRNA, promoting its decay and inhibiting apoptosis.
Conclusions:
- The circSETD3/FXR1/ECT2 axis is crucial in acquired gefitinib resistance in NSCLC.
- CircSETD3 demonstrates potential as a biomarker for predicting gefitinib resistance.
- Targeting circSETD3 may offer a novel therapeutic strategy for overcoming gefitinib resistance in NSCLC.
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