Background
Cisplatin (DDP) is the principal agent used for chemotherapy in patients with non-small cell lung cancer (NSCLC). Nevertheless, DDP resistance is an essential cause for a worse prognosis of patient. Therefore, this study proposes to discover features of miR-424-5p in DDP resistance of NSCLC. Method: After exogenous modulation of miR-424-5p expression, A549 cell activity was measured using CCK-8 and flow cytometry. A549/DDP and A549/DDP-associated subcutaneous tumor model were constructed to investigate the effect of miR-424-5p on DDP resistance in NSCLC in vivo. TargetScan and JASPAR databases predicted the potential molecular mechanism of miR-424-5p. A549-and A549/DDP-derived exosomes were isolated and characterized using a transmission electron microscope and nanoparticle tracking analysis. Result: Overexpression of miR-424-5p facilitated proliferation and DDP resistance in A549 cells, and knockdown of miR-424-5p did the opposite. Knockdown of miR-424-5p enhanced DDP restriction on tumor weight and volume. Moreover, SOCS5 and SOCS56 (SOCS5/6) were downstream targets of miR-424-5p. miR-424-5p down-regulated SOCS5/6 expression to activate JAK2/STAT3 and PI3K/AKT pathways. Notably, tumor protein p53 (TP53) is a transcription factor for the miR-424-5p host gene, as confirmed by the dual-luciferase reporter gene. Cellular and animal experiments indicated that TP53 limited the regulatory function of miR-424-5p on NSCLC growth, DDP resistance, and related molecules. Interestingly, miR-424-5p was markedly enriched in A549/DDP cell-derived exosomes than in A549 cell-derived exosomes, and TP53 down-regulated miR-424-5p expression in A549/DDP cell-derived exosomes.
Conclusion
DDP-resistant cell-derived exosome miR-424-5p contributes to NSCLC growth and DDP resistance by targeting SOCS5 and SOCS6 to activate JAK2/STAT3 and PI3K/AKT pathways, which are blocked by TP53.