eIF3a R803K mutation mediates chemotherapy resistance by inducing cellular senescence in small cell lung cancer

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Chemotherapy resistance is a major challenge in treating small cell lung cancer (SCLC).
• Limited access to serial tumor tissue samples hinders the study of resistance mechanisms.
• Circulating tumor DNA (ctDNA) offers a non-invasive approach to study tumor evolution during treatment.

Purpose of the Study:

• To investigate the role of somatic mutations in ctDNA in acquired chemotherapy resistance in SCLC.
• To identify specific mutations associated with resistance and explore their functional implications.
• To evaluate potential therapeutic strategies targeting chemotherapy-resistant SCLC.

Main Methods:

• Analysis of ctDNA from SCLC patients before and after chemotherapy.
• Identification and validation of somatic mutations using next-generation sequencing.
• Functional studies in cell lines to assess the impact of identified mutations on chemoresistance and senescence.
• Evaluation of drug synergy in eIF3A R803K mutant cells.

Main Results:

• The somatic mutation eIF3A R803K was identified in ctDNA of SCLC patients with acquired drug resistance.
• This mutation was confirmed in a larger cohort of lung cancer patients receiving chemotherapy.
• eIF3A R803K mutation was found to decrease tumor cell proliferation but increase chemoresistance by promoting cellular senescence.
• Fisetin demonstrated a synergistic effect with chemotherapy in eIF3A R803K mutant cells.

Conclusions:

• The eIF3A R803K somatic mutation in ctDNA may serve as a predictive biomarker for chemotherapy resistance in SCLC.
• This mutation promotes chemotherapy resistance through the induction of cellular senescence.
• The senolytic drug fisetin can potentially reverse chemotherapy resistance mediated by the eIF3A R803K mutation.