Loss of hepatocyte ERBB3 but not EGFR impairs hepatocarcinogenesis

Area of Science:

• Oncology
• Molecular Biology
• Hepatology

Background:

• Epidermal growth factor receptor (EGFR) and ERBB3 are implicated in hepatocellular carcinogenesis (HCC).
• The specific role of EGFR and ERBB3 activity in HCC development remains unclear.
• Gain-of-function EGFR mutations are linked to increased kinase activity.

Purpose of the Study:

• To investigate the impact of altered EGFR and ERBB3 activity on HCC development.
• To determine the effect of EGFR and ERBB3 gene ablation on liver tumor progression.
• To elucidate the downstream signaling pathways involved in ERBB3-mediated HCC promotion.

Main Methods:

• Utilized Egfr(Dsk5) mutant mice with increased basal EGFR kinase activity.
• Generated hepatocyte-specific EGFR and ERBB3 gene ablation models.
• Employed a diethylnitrosamine-induced HCC model in mice.

Main Results:

• Egfr(Dsk5) mutant mice developed spontaneous HCC with increased EGFR, ERBB2, ERBB3, AKT, and ERK1,2 activation.
• Loss of EGFR or ERBB3 did not affect normal liver development or regeneration.
• Hepatocellular ERBB3 ablation, post-tumor initiation, retarded HCC formation and proliferation.
• ERBB3-null tumors showed diminished phospho-STAT3 levels, without increased apoptosis or altered PI3K activity.

Conclusions:

• ERBB3, but not EGFR, plays a critical role in promoting established hepatocellular carcinogenesis.
• ERBB3 may facilitate HCC development through STAT3 activation.
• Targeting ERBB3 could be a potential therapeutic strategy for HCC.