Hsa-miR-483-5p/mRNA network that regulates chemotherapy resistance in locally advanced rectal cancer identified through plasma exosome transcriptomics.

BACKGROUND

Chemoresistance is the primary contributor to distant metastasis in the context of neoadjuvant chemoradiotherapy (nCRT) for rectal cancer. However, the underlying mechanisms remain elusive.

AIM

To detect the differential expression profiles of plasma exosomal microRNAs (miRNAs) in poor and good responders and explore the potential mechanisms of chemoresistance.

METHODS

In this study, the profiles of plasma exosomal miRNAs were compared in two dimensions according to treatment responses (poor/good responders) and treatment courses (pre/post-nCRT) using RNA sequencing.

RESULTS

Exosome hsa-miR-483-5p was up-regulated in good responders post-nCRT. Bioinformatics analysis revealed that the target genes of hsa-miR-483-5p were mainly enriched in tumor-specific pathways, such as the MAPK signaling pathway, EGFR tyrosine kinase inhibitor resistance, Toll-like receptor signaling pathway, VEGF signaling pathway, and mTOR signaling pathway. Further analysis indicated that MAPK3, RAX2, and RNF165 were associated with inferior recurrence-free survival in patients with rectal cancer, and the profiles of MAPK3, TSPYL5, and ZNF417 were correlated with tumor stage. In addition, the expression profiles of MAPK3, RNF165, and ZNF417 were negatively correlated with inhibitory concentration 50 values. Accordingly, an hsa-miR-483-5p/MAPK3/RNF 165/ZNF417 network was constructed.

CONCLUSION

This study provides insights into the mechanism of chemoresistance in terms of exosomal miRNAs. However, further research is required within the framework of our established miRNA-mRNA network.