Strong carcinogenic stress response induction of preneoplastic cells positive for GST-P in the rat liver: Physiological mechanism for initiation.

To identify experimental conditions that induce preneoplastic cells positive for glutathione S-transferase P-form (GST-P) in the rat liver by new approaches, and analysis of the mechanism of cancer initiation based on the findings. The experimental protocols employed to induce GST-P+ preneoplastic cells in rat liver were as follows. Protocol 1: adult rats were fed basal diet containing 2-acetylaminofluorene (AAF, 0.02% by wt) and high concentrations of N-acetyl-l-cysteine (0.5%) over 10 weeks. Protocol 2: rats were subjected to partial hepatectomy (2/3PH), followed by an AAF (0.04%) diet for two more weeks. Vibratome-prepared liver sections were then immunostained for GST-P. GST-P was inducible in the rat liver in response to the strong carcinogenic stress by AAF in the two experimental protocols. When examined immunocytochemically with vibratome sections, the biliary tracts of hepatocytes, GST-P+ single hepatocytes and foci were heavily positive for the marker enzyme in addition to ordinary cytosolic staining of preneoplastic cell populations. The biliary tracts of hepatocytes were severely injured, and the excretory portions of GST-P+ single hepatocytes were significantly injured. The cytotoxic action of AAF that give rise to the GST-P+ single hepatocytes was suggested to be an injury to the excretory pump(s) and the duct of hepatocytes. A new physiological mechanism was hypothesized for the induction of preneoplastic cell populations in the rat liver instead of a genetic mechanism.

Satoh K 《-》

A new mechanism of cancer initiation that involves the transformation of hepatocytes into preneoplastic single hepatocytes and minifoci positive for glutathione S-transferase P-form (GST-P) in rat livers: 3D analysis using a vibratome.

Satoh K 《Cancer Medicine》

Bile duct-bound growth of precursor cells of preneoplastic foci inducible in the initiation stage of rat chemical hepatocarcinogenesis by 2-acetylaminofluorene.

Satoh K ，Yamakawa D ，Sugio H ，Kida K ，Sato T ，Hosoi K ，Hayakari M ... -  《-》

Early initiating and promoting effects in 2-AAF-induced rat liver carcinogenesis: an immunohistochemical study.

Hadjiolov N ，Bitsch A ，Neumann HG 《CANCER LETTERS》

Dose-dependent effects of 2-acetylaminofluorene on hepatic foci development and cell proliferation in rats.

Tiwawech D ，Hasegawa R ，Kurata Y ，Tatematsu M ，Shibata MA ，Thamavit W ，Ito N ... -  《CARCINOGENESIS》