The expression of exosomal and cellular miRNAs in predicting oxaliplatin resistance in colorectal cancer cells: an in silico and in vitro study

Background: Colorectal cancer (CRC) is a common gastrointestinal cancer, and even though oxaliplatin chemotherapy is effective, there is a high likelihood of relapse, indicating the presence of oxaliplatin-resistant CRC. Therefore, it is crucial to comprehend the molecular mechanisms of oxaliplatin resistance and develop effective strategies to counter drug resistance. Numerous studies have demonstrated the close association between microRNAs (miRNAs) and drug resistance in CRC. In this study, we aimed to identify the essential exosomal and cellular miRNA related to oxaliplatin resistance in the CRC cell line HCT-116.

Methods: The miRNA expression profile of CRC cells with resistance to oxaliplatin was analyzed. The effectiveness of diagnostics and biomarker potency of miRNAs were evaluated by receiver operating characteristic (ROC) analysis. Target miRNAs were identified, and the enrichment analysis was assessed based on Gene Ontology (GO), Reactome, and Human Disease Ontology (DO). In vitro experiments, oxaliplatin-resistant HCT-116 cells (HCT116-OXA) were developed, and the exosomes were isolated and characterized from HCT116-OXA and HCT116 cells. The expression of the selected miRNAs was evaluated in HCT116-OXA cells and their exosomes, and they were compared to HCT-116 cells using quantitative real-time PCR.

Results: This study revealed that a combination of miR-4326, miR-3615, miR-7974, miR-130b-3p, and miR-454-3p exhibited the highest area under the curve (AUC), sensitivity, specificity, and superior diagnostic and predictive performance. In vitro experiments, HCT116-OXA cells displayed reduced early and late apoptosis, a bypass of S phase arrest, prolonged doubling time, and higher IC₅₀ compared to parental cells. The expression of miR-454-3p, miR-130b-3p, miR-7974, miR-3615, and miR-4326 was decreased in HCT116-OXA cells as compared to sensitive cells. However, a significantly higher expression of miR-130b-3p and miR-4326 was observed in the isolated exosomes of HCT116-OXA cells as compared to the sensitive cells.

Conclusions: The low expression of miR-454-3p, miR-7974, and miR-3615 in CRC cells or high expression of miR-130b-3p and miR-4326 in isolated exosomes could predict the response to oxaliplatin therapy. This indicates the potential of these specific miRNAs to serve as predictive markers for the response to oxaliplatin therapy.