Radiotherapy promotes M2 polarization of macrophages through the regulation of the PTEN/PI3K/AKT signaling pathway through miR-616-3p in lung cancer cell-derived exosomes.

Resistance to radiation therapy (RT) poses a significant challenge in managing non-small cell lung cancer (NSCLC). Despite research into how tumor-sourced exosome (Exo) miRNAs influence tumor RT resistance and macrophage M2 polarization, the process through which Exos with miR-616-3p modulate macrophage polarization to impact NSCLC RT resistance is still not well understood. The objective of this research was to investigate the molecular processes by which RT regulates M2 polarization of macrophages via the Exos miR-616-3p derived from NSCLC cells. Identification of Exos was conducted using transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Flow cytometry, immunofluorescence, and ELISA were employed to verify the macrophage phenotype. The expression of miR-616-3p was identified using RT-qPCR, and the targeting relationship between miR-616-3p and PTEN was confirmed through dual-luciferase reporter gene tests and RIP identification. In NSCLC, miR-616-3p showed high expression levels and was linked to RT and M2 polarization in macrophages. Subsequent research indicated that RT prompted the influx of Exos-miR-616-3p from NSCLC cells into macrophages. Both the H1299 lung cancer cell line and the M0 macrophages underwent co-culture. Findings indicated that NSCLC cells induced by RT and Exos elevated the proportion of CD163 + CD206 + positive cells in macrophages via miR-616-3p and augmented Arg1, IL-10, TGF-β1, and VEGF levels, and enhanced M2 polarization in macrophages. Regarding the molecular process, miR-616-3p suppressed PTEN protein expression while concurrently boosting the levels of p-PI3K/PI3K and p-AKT/AKT; either amplifying PTEN or suppressing PI3K could markedly weaken the impact of ionizing radiation (IR), inhibiting the impact of NSCLC cell Exos on macrophages' M2 polarization. This research reveals that in NSCLC cells induced by IR, Exos with miR-616-3p expression reduce PTEN levels and enhance the PI3K/AKT signaling pathway, leading to increased M2 polarization in macrophages and worsening NSCLC progression.