Exosomes transmit T790M mutation-induced resistance in EGFR-mutant NSCLC by activating PI3K/AKT signalling pathway

Area of Science:

• Oncology
• Molecular Biology
• Cell Biology

Background:

• Exosomes mediate intercellular communication and can transfer drug resistance.
• Acquired resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors (EGFR-TKIs) is a major challenge in Non-Small Cell Lung Cancer (NSCLC).
• The role of exosomes from EGFR T790M-mutant NSCLC cells in transferring gefitinib resistance is not well understood.

Purpose of the Study:

• To investigate whether exosomes from EGFR T790M-mutant NSCLC cells can transfer gefitinib resistance to sensitive NSCLC cells.
• To elucidate the underlying mechanism of exosome-mediated gefitinib resistance.
• To identify key molecular players, such as microRNAs (miRNAs), involved in this process.

Main Methods:

• Isolation of exosomes from T790M-mutant (H1975) and sensitive (PC9) NSCLC cell lines.
• In vitro and in vivo experiments to assess gefitinib resistance transfer.
• Small RNA sequencing and quantitative real-time PCR (qRT-PCR) for miRNA profiling.
• Western blotting to analyze PI3K/AKT signaling pathway activation.

Main Results:

• Exosomes from H1975 cells conferred gefitinib resistance to PC9 cells both in vitro and in vivo.
• Exosome treatment activated the PI3K/AKT signaling pathway in recipient PC9 cells.
• miR-522-3p was identified as a key miRNA transferred by exosomes, and its upregulation induced gefitinib resistance in PC9 cells.

Conclusions:

• Exosomes derived from EGFR T790M-mutant NSCLC cells promote gefitinib resistance in sensitive cells.
• The PI3K/AKT pathway and miR-522-3p are crucial mediators of this exosome-driven drug resistance.
• These findings highlight a novel mechanism of acquired resistance to EGFR-TKIs in NSCLC, suggesting potential therapeutic targets.