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.