In this study, we aimed to explore key micro(mi)RNAs and their potential regulatory mechanisms induced by honokiol treatment in non-small cell lung cancer (NSCLC) cells.

NSCLC A549 cells were treated with 0 (control) or 45 μM honokiol. Cell proliferation and migration were determined using CCK-8 and transwell assay, respectively, and apoptosis was determined using flow cytometry. RNA-sequencing was performed to detect the transcript expression levels. The differentially expressed miRNAs (DE-miRNAs) between the honokiol group and the control group were screened and analyzed for their functions and pathways. Then, protein-protein interaction (PPI) networks and miRNA-mRNA regulatory networks were constructed. In addition, survival analysis based on the key miRNAs was performed. Finally, the expression of the key miRNAs and their target genes were determined, and their effects on drug sensitivity were validated using their inhibitors.

Cell proliferation and migration were inhibited (P < 0.01), and the apoptosis rate was increased (P < 0.01) after honokiol treatment compared to that in the control group. A total of 26 upregulated and 20 downregulated DE-miRNAs were screened. DE-miRNAs were enriched in 10 pathways and 48 biological processes, such as the PI3K/AKT signaling pathway (involving miR-148a-3p). The miRNA-mRNA regulatory networks involved eight upregulated (including miR-148a-3p and let-7c-5p) and seven downregulated miRNAs (including miR-7-5p) and 190 target mRNAs. Survival analysis revealed that let-7c-5p, miR-148a-3p, and miR-148a-5p levels correlated with NSCLC prognosis. The expression of let-7c-5p, miR-148a-3p, and miR-148a-5p was significantly increased and negatively correlated with the expression of their target genes. The cytological effects of honokiol on A549 cells was partly reversed by treatment with the inhibitors of Let-7c-5p and miR-148a-3p.

Let-7c-5p, miR-148a-3p, miR-148a-5p, and miR-7-5p are favorable indicators of NSCLC patients treated with honokiol.