microRNA-204 as a crucial cancer stem cell related miRNA inhibits stemness of gastric cancer by targeting CD44 and EPCAM

BACKGROUND: Cancer stem cells (CSCs) and normal stem cells share key properties such as self-renewal and differentiation capacity, yet the microRNAs (miRNAs) that are differentially expressed between them remain poorly characterized. This study aimed to identify such miRNAs, with a focus on microRNA-204 (miR-204), and to investigate its functional role and regulatory mechanisms in gastric cancer. METHODS: Using miRNA microarray data from public databases (GEO and TCGA), we identified miR-204 as a stemness-related miRNA. Its expression was validated in clinical gastric cancer tissues and cell lines. Functional assays, including colony formation, Transwell, tumorsphere formation, and extreme limiting dilution analysis, were performed to assess the effects of miR-204 on proliferation, metastasis, and stemness. Luciferase reporter assays confirmed direct targeting of CD44 and EPCAM. The role of TP53 in miR-204 maturation was investigated using TP53-knockout mice and TP53 overexpression cell models. RESULTS: miR-204 was identified as a crucial miRNA, upregulated in normal stem cells but significantly downregulated in CSCs and multiple human cancers, including gastric cancer. Low miR-204 expression correlated with advanced TNM stage and poor overall survival in gastric cancer patients. Restoring miR-204 expression potently inhibited gastric cancer cell proliferation, metastasis, and stemness properties. Mechanistically, miR-204 directly targeted and suppressed the expression of two key CSC regulators, CD44 and EPCAM. Furthermore, we discovered that TP53 mutation is a major cause of miR-204 downregulation, and demonstrated that TP53 promotes the maturation of miR-204 rather than its primary transcription. CONCLUSIONS: Our study unveils miR-204 as a pivotal tumor suppressor that distinguishes CSCs from normal stem cells. It functions by targeting the CD44/EPCAM axis to inhibit gastric cancer stemness, a process governed by a novel TP53-miR-204 regulatory circuit. These findings position miR-204 as a promising prognostic biomarker and therapeutic target for eradicating CSCs in gastric cancer.