Targeting endogenous DLK1 exerts antitumor effect on hepatocellular carcinoma through initiating cell differentiation

Area of Science:

• Oncology
• Molecular Biology
• Hepatology

Background:

• Cancer stem cells (CSCs) drive tumor initiation and progression in hepatocellular carcinoma (HCC).
• Delta-like homolog 1 (DLK1) has been identified as a potential therapeutic target for HCC CSCs.
• The precise therapeutic efficacy and molecular mechanisms of targeting DLK1 in HCC remain to be fully elucidated.

Purpose of the Study:

• To investigate the therapeutic efficacy of DLK1 knockdown in human HCC.
• To elucidate the underlying cellular and molecular mechanisms of DLK1's role in HCC progression.
• To evaluate DLK1 as a therapeutic target in preclinical HCC models.

Main Methods:

• Utilized a tet-inducible short hairpin RNA (shRNA) system for DLK1 knockdown in human HCC cells.
• Employed adenovirus-mediated DLK1 knockdown in orthotopic xenograft mouse models.
• Investigated DLK1's role in a diethylnitrosamine (DEN)-induced mouse HCC model using adenoviral vectors.
• Analyzed cell cycle progression, expression of key molecular markers (AFP, EpCAM, KRT18, KRT19), and tumor growth.

Main Results:

• DLK1 knockdown significantly inhibited HCC cell proliferation, spheroid formation, and in vivo xenograft tumor growth.
• Adenovirus-mediated DLK1 knockdown reduced tumor size in orthotopic xenograft models and inhibited tumor progression in a DEN-induced HCC model.
• DLK1 knockdown delayed cell cycle G1-S transition, decreased cyclin E1 and D1 expression, reduced hepatic progenitor cell markers (AFP, EpCAM), and increased differentiated hepatocyte markers (KRT18, KRT19).

Conclusions:

• Targeting endogenous DLK1 demonstrates significant antitumor effects in HCC.
• DLK1 inhibition may exert its antitumor effect by promoting the differentiation of HCC cells.
• DLK1 represents a promising therapeutic target for hepatocellular carcinoma treatment.