tRF-28-ZJ47D112Z4DZ suppresses gastric cancer progression via Ago2-mediated regulation of the CCND1-associated cell cycle pathway and serves as a complementary plasma biomarker.

INTRODUCTION: Gastric cancer (GC) remains a leading cause of cancer-related mortality worldwide, highlighting the need for improved non-invasive biomarkers for early detection and prognostic evaluation. tRNA-derived fragments (tRFs) have emerged as regulatory non-coding RNAs in cancer, but their biological and clinical significance in GC remains unclear. OBJECTIVES: To evaluate the diagnostic, prognostic, and biological significance of tRF-28-ZJ47D112Z4DZ (tRF-28) in GC and investigate its underlying molecular mechanism. METHODS: tRF-28 was identified using a stepwise screening strategy, and an absolute quantification assay was established for plasma detection. Receiver operating characteristic (ROC) analysis, survival analysis, and Cox regression models were used to evaluate its clinical significance. Gain- and loss-of-function studies in GC cells, together with xenograft overexpression models, were performed to investigate its biological functions. RNA immunoprecipitation, dual-luciferase reporter assays, rescue experiments, and immunohistochemistry were used to explore the underlying mechanism. RESULTS: Plasma tRF-28 levels progressively decreased from healthy controls to precancerous lesions and GC patients. tRF-28 demonstrated diagnostic value for precancerous lesions (AUC = 0.713) and showed moderate but reproducible diagnostic performance for GC in both the training and validation cohorts (AUC = 0.762 in the training cohort). Reduced plasma tRF-28 levels were associated with poor differentiation, deeper invasion, and unfavorable overall survival, and multivariate Cox analysis identified tRF-28 as an independent protective prognostic factor. Functionally, tRF-28 inhibited GC cell proliferation, colony formation, invasion, migration, and cell cycle progression while promoting apoptosis. Mechanistically, tRF-28 associated with Argonaute 2 (Ago2) and directly targeted the 3' untranslated region of CCND1, thereby suppressing the Cyclin D1/CDK4/p-Rb signaling pathway. Xenograft studies further confirmed its tumor-suppressive effect in vivo. CONCLUSIONS: tRF-28 suppresses GC progression through regulation of the CCND1-associated cell cycle pathway and may serve as a complementary plasma biomarker for GC diagnosis and prognostic assessment.