Clinical relevance and mechanistic investigation of miR-1908-5p as a prognostic biomarker in colorectal cancer.

[BACKGROUND] Colorectal cancer (CRC) is characterized by a complex pathogenesis and substantial heterogeneity in prognosis.

[OBJECTIVE] This study aims to elucidate the clinical significance of miR-1908-5p in CRC, as well as its association with clinicopathological parameters and patient prognosis.

[METHOD] miR-1908-5p expression in tumor tissues was quantified by RT-qPCR. Survival outcomes were assessed using the Kaplan-Meier method. The chi-square (χ) test and Cox regression analysis were employed to evaluate clinicopathological correlations and prognostic value.miR-1908-5p was compared between NCM460 and CRC lines (HT-29, HCT116), overexpressed, and functionally tested by CCK-8 and Transwell assays. TargetScan and luciferase assay verified the targeting of SCAMP4 3'-UTR. qPCR and Pearson analysis defined their correlation in CRC.

[RESULTS] miR-1908-5p is downregulated in CRC tumors versus adjacent normal mucosal tissues. Low expression predicts poor prognosis and is associated with reduced survival rates in colorectal cancer, correlating with advanced TNM stage and elevated serum CA19-9 levels. CRC lines (HT-29 and HCT116) show reduced miR-1908-5p compared to NCM460. miR-1908-5p mimic suppresses proliferation, migration, and invasion. TargetScan-predicted binding to SCAMP4 3'-UTR was validated by dual-luciferase reporter assay. miR-1908-5p overexpression lowers SCAMP4, which is overexpressed in tumor tissues and exhibits an inverse correlation with miR-1908-5p.

[CONCLUSION] miR-1908-5p is downregulated in CRC, correlates with TNM stage, nodal metastasis, elevated CA19-9 levels, and poor survival, and suppresses CRC cell proliferation, migration, and invasion by directly targeting SCAMP4, thereby qualifying as a potential prognostic biomarker for CRC.