Inhibition of β-catenin and KRAS Expressions by Piper betle in Azoxymethane-induced Colon Cancer of Male Fischer 344 Rats

OBJECTIVE: To investigate the chemopreventive effect of Piper betle (PB) on preneoplastic lesions (aberrant crypt foci [ACF] induced by azoxymethane (AOM) in rats and its effect on colorectal cancer biomarkers (beta-catenin, KRAS, p53 and p21). STUDY DESIGN: A total of 32 male Fischer 344 rats were divided into phase 1 and phase 2 groups (8 and 24 weeks of AOM administration, respectively). Each phase was divided into 4 groups: control or normal saline (NS) (1 mL/kg), AOM (15 mg/kg body weight, once weekly for 2 weeks), PB (75 mg/kg body weight) and AOM + PB. PB was force-fed to rats a week after the second dose of AOM and NS. The colon was cut open longitudinally for methylene blue and immunohistochemistry staining. RESULTS: AOM administration showed formation of ACF at 8 and 24 weeks. PB, however, did not reduce ACF formation at either week, but it managed to reduce beta-catenin expression and KRAS found highly expressed in the AOM group of phase 1 rats. No immunoreactivities of p53 and p21 were detected in phase 2 rats, but instead inflammatory cells were visible in between the lesions. CONCLUSION: PB may act as a potential chemopreventive agent in the early stage of colon carcinogenesis by suppressing the expressions of beta-catenin and KRAS.