ToxSci Advance Access originally published online on April 7, 2008
Toxicological Sciences 2008 104(1):100-106; doi:10.1093/toxsci/kfn071
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Evidence that the Anticarcinogenic Effect of Caffeic Acid Phenethyl Ester in the Resistant Hepatocyte Model Involves Modifications of Cytochrome P450
* Departamento de Biología Celular
Sección Externa de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Avenida IPN No. 2508 Colonia San Pedro Zacatenco, México 14, DF, CP 07360, México
1 To whom correspondence should be addressed at Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Avenida IPN No. 2508 Colonia San Pedro Zacatenco, México 14, DF, CP 07360, México. Fax: (52) 55 57473393. E-mail: svilla{at}cell.cinvestav.mx.
Received October 3, 2007; accepted March 28, 2008
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Abstract |
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Caffeic acid phenethyl ester (CAPE), a natural component of propolis, shows anticarcinogenic properties in the modified resistant hepatocyte model when administered before initiation or promotion of hepatocarcinogenesis process; however, information about the mechanism underlying this chemoprotection is limited. The aim of this work was to characterize the effect of CAPE on cytochrome P450 (CYP), which is involved in diethylnitrosamine (DEN) metabolism during the initiation stage of chemical hepatocarcinogenesis. Male Fischer-344 rats were treated as in the modified resistant hepatocyte model. Liver samples were obtained at four different times: at 12 h after pretreatment with CAPE and at 12 and 24 h and 25 days after DEN administration. Liver damage was determined by histology with hematoxylin and eosin, measurement of total CYP levels and enzyme activity, and 
-glutamyl transpeptidase–positive (GGT+) staining of hepatocyte foci. CAPE administration prevented DEN-induced necrosis at 24 h. It also decreased O-dealkylation of 7-ethoxy-resorufin (EROD), O-dealkylation of 7-methoxyresorufin (MROD), and 7-pentoxy-resorufin activities at 12 h after its administration and EROD and MROD activities at 12 h after administration of DEN. CAPE treatment decreased GGT+ foci by 59% on day 25. Our results suggest that CAPE modifies the enzymatic activity of CYP isoforms involved in the activation of DEN, such as CYP1A1/2 and CYP2B1/2. These findings describe an alternative mechanism for understanding the ability of CAPE to protect against chemical hepatocarcinogenesis.
Key Words: chemoprevention; cytochrome P450; DEN metabolism; hepatocarcinogenesis.