Cytokeratin expression during AFB1-induced carcinogenesis

Area of Science:

• Hepatocarcinogenesis research
• Molecular biology of cancer
• Toxicology and carcinogenesis

Background:

• Aflatoxin B1 (AFB1) is a potent hepatocarcinogen.
• Understanding early cellular changes in AFB1-induced liver cancer is crucial.
• Cytokeratin (CK) expression patterns can indicate cell lineage and transformation.

Purpose of the Study:

• To investigate cytokeratin (CK) expression during early stages of AFB1-induced rat liver carcinogenesis.
• To identify potential cell lineages involved in AFB1-induced tumorigenesis.
• To evaluate CK expression as a marker for pre-neoplastic lesions.

Main Methods:

• Feeding rats with AFB1 for 24 weeks.
• Utilizing a novel monoclonal antibody (MRCTU/J1) recognizing rat CK18.
• Employing antibodies against human CK8, 18, and 19 for immunodetection.
• Analyzing CK expression in altered foci and tumors.
• Comparing CK expression with gamma-glutamyltranspeptidase as a marker.

Main Results:

• AFB1-induced liver tumors exhibited diverse CK expression patterns, including normal hepatocyte, bile duct, and oval cell phenotypes.
• Hepatocytes displaying a bile duct CK phenotype were observed in early carcinogenesis stages.
• CK overexpression, particularly CK19, was a more selective and consistent marker for altered foci and tumors compared to gamma-glutamyltranspeptidase.
• CK expression patterns were maintained in normal and hepatoma-derived cell lines.

Conclusions:

• AFB1-induced liver transformation may originate from multiple cell types.
• Early detection of bile duct-like CK phenotypes in hepatocytes suggests a role in carcinogenesis.
• CKs, especially CK19, are reliable biomarkers for identifying pre-neoplastic and neoplastic lesions in AFB1-induced liver cancer.