Effects of Isoliquirithigenin on the Development of Preneoplastic Liver Lesions Caused by a Choline-Deficient, L-Amino Acid-Defined Diet and on the Urinary Bladder Carcinogenesis by N-Butyl-N-(4-hydroxybutyl)nitrosamine in Rats

Abstract

Cancer chemopreventive efficacy of a chalcone, isoliquiritigenin (ISO), was assessed on the rat hepatocarcinogenesis associated with fibrosis caused by a choline-deficient, L-amino acid-defined (CDAA) diet, using glutathione S-transferase placental form (GST-P)-positive preneoplastic foci as the end point lesion, and on the rat superficial bladder carcinogenesis initiated by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN). ISO, when given to F344 male rats at the doses of 12.5, 50, 100, and 200 ppm in the CDAA diet for 15 weeks, did not significantly affect the number and size of GST-P-positive foci and the % liver area occupied by the foci. However, it tended to decrease the grade of liver fibrosis. ISO, which was given in a basal diet at doses of 12.5, 25, and 100 ppm for 12 weeks to F344 male rats initiated by 0.05% BBN in drinking water for 12 weeks, also exhibited no clear chemopreventive effects on the development of urinary bladder tumors. Nevertheless, it tended to decrease the multiplicity of nodulo-papillary hyperplasia but not of transitional cell carcinoma (TCC), and differentiation grade of TCCs. The results indicate that ISO at least at the doses used in the present study, possesses no clear cancer chemopreventive efficacy on rat hepatocarcinogenesis caused by a CDAA diet and on rat superficial urinary bladder carcinogenesis by BBN.