IGF2BP1-Mediated m⁶A Modification Stabilizes HMGA2 mRNA to Promote Intrahepatic Cholangiocarcinoma Progression.
BACKGROUND & AIMS: Intrahepatic cholangiocarcinoma (iCCA) remains a lethal malignancy with a lack of effective therapies, underscoring the critical need to identify novel therapeutic targets. The high-mobility group protein A2 (HMGA2) is an oncogenic architectural transcription factor aberrantly overexpressed in multiple cancers; yet its function and regulatory mechanisms in iCCA are poorly defined. This study aimed to elucidate the clinical significance and molecular mechanism of HMGA2 in iCCA progression. METHODS: We integrated analyses across 4 independent iCCA cohorts (The Cancer Genome Atlas, 2 Zhongshan Hospital cohorts, and our 192-patient institutional cohort). Functional investigations were conducted using iCCA cell lines and multiple mouse models, including xenograft, syngeneic, YAP/AKT-driven spontaneous iCCA, and metastasis models. RESULTS: We demonstrated that HMGA2 was significantly upregulated in iCCA, correlating with poor survival, and exhibited sexually dimorphic prognostic effects with a female-specific link to perineural invasion. Functionally, HMGA2 depletion suppressed iCCA cell proliferation, migration, in vivo tumor growth and metastasis. Mechanistically, HMGA2 expression was positively regulated by the N6-methyladenosine reader insulin-like growth factor 2 messenger RNA-binding protein 1 (IGF2BP1), which directly bound to and stabilized HMGA2 messenger RNA via its KH3-4 domains in an N6-methyladenosine-dependent manner. High IGF2BP1 expression predicted poor iCCA prognosis, was required for HMGA2-driven progression, and the axis promoted PI3K-AKT pathway activation. CONCLUSIONS: Our results reveal a critical role for the IGF2BP1-HMGA2 axis in iCCA pathogenesis, thereby highlighting its potential as a therapeutic target.