Serum-derived exosomal miR-125a-3p predicts the response to anti-programmed cell death-1/programmed cell death-ligand 1 monotherapy in patients with non-small cell lung cancer.

• Exosomal miR-125a-3p in serum predicted response to anti-PD-1/PD-L1 therapy in NSCLC. • MiR-125a-3p was a more useful predictor than tumoral PD-L1 in low PD-L1 expression. • High expression of miR-125a-3p was associated with worse prognosis. • MiR-125a-3p regulates PD-L1 expression via neuregulin 1 suppression in NSCLC cells. Versatile biomarkers for immune checkpoint inhibitors (ICI) efficacy in patients with cancer remain to be identified. Liquid biopsy using serum-derived exosomal microRNAs (miRNAs) are widely investigated as diagnostic and therapeutic outcome predictors in patients with cancer. However, exosomal miRNAs linked to the response to ICI in patients with non-small cell lung cancer (NSCLC) remain elusive thus far. Methods: The value of serum-derived exosomal miRNAs in predicting the effect of anti-programmed cell death-1 (PD-1)/anti-programmed cell death-ligand 1 (PD-L1) monotherapy in 41 patients with advanced NSCLC was assessed. We performed functional analysis of candidate miRNAs using NSCLC cell lines. Results: Exosomal miR-125a-3p was associated with response to treatment with ICI. Exosomal miR-125a-3p was more useful in predicting response to ICI versus tumoral PD-L1 in patients with low PD-L1 expression <50 %). Moreover, high expression of miR-125a-3p was associated with worse progression-free and overall survival. In H1975 and H441 cells, induction of miR-125a-3p regulated PD-L1 expression via suppression of neuregulin 1 (NRG1). Conclusions: Exosomal miR-125a-3p is a potential predictor of response to anti-PD-1/PD-L1 therapy in advanced NSCLC patients with low PD-L1 expression. [ABSTRACT FROM AUTHOR]