Journal Article

Chemopreventive <i>N</i>-(4-hydroxyphenyl)retinamide (fenretinide) targets deregulated <i>NF-κB</i> and <i>Mat1A</i> genes in the early stages of rat liver carcinogenesis

Maria M. Simile, Gabriella Pagnan, Fabio Pastorino, Chiara Brignole, Maria R. De Miglio, Maria R. Muroni, Giuseppina Asara, Maddalena Frau, Maria A. Seddaiu, Diego F. Calvisi, Francesco Feo, Mirco Ponzoni and Rosa M. Pascale

in Carcinogenesis

Volume 26, issue 2, pages 417-427
Published in print February 2005 | ISSN: 0143-3334
Published online February 2005 | e-ISSN: 1460-2180 | DOI: http://dx.doi.org/10.1093/carcin/bgh315
Chemopreventive N-(4-hydroxyphenyl)retinamide (fenretinide) targets deregulated NF-κB and Mat1A genes in the early stages of rat liver carcinogenesis

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Cell-cycle deregulation is an early event of hepatocarcinogenesis. We evaluated the role of changes in activity of nuclear factor κB (NF-κB) and some related pathways in this alteration, and the interference of N-(4-hydroxyphenyl)retinamide (HPR), a retinoid chemopreventive for various cancer types, with these molecular mechanisms and the evolution of preneoplastic liver to cancer. Male F344 rats, initiated according to the ‘resistant hepatocyte’ model of liver carcinogenesis, received weekly 840 nmol of liposomal HPR (SL-HPR)/100 g body wt or empty liposomes, between 5 and 25 weeks after initiation. Inhibition of DNA synthesis and induction of apoptosis occurred in pre-cancerous lesions, 7–147 days after starting SL-HPR, and a decrease in carcinoma incidence and multiplicity was observed 25 weeks after arresting treatment. An increase in NF-κB expression and binding activity, and under-expression of the inhibitor κB-α (IκB-α) were found in preneoplastic liver and neoplastic nodules, 5 and 25 weeks after initiation, respectively. These lesions also showed low expression of Mat1A and low activity of methionine adenosyltransferase I/III, whose reaction product, S-adenosyl-l-methionine, enhances IκB-α expression. SL-HPR prevented these changes and induced a decrease in expression of iNos, c-myc, cyclin D1 and Vegf-A genes, that were over-expressed in preneoplastic liver and nodules, and a decrease in Bcl-2/Bax, Bcl-2/Bad and Bcl-xL/Bax mRNA ratios with respect to the lesions of control rats. Liposomes alone did not influence the parameters tested. These results indicate that signal transduction pathways controlled by NF-κB, nitric oxide and S-adenosyl-l-methionine are deregulated in pre-cancerous lesions. Recovery from these alterations by SL-HPR is associated with chemoprevention of hepatocarcinogenesis. Overall, these studies elucidate some molecular changes, in early stages of hepatocarcinogenesis, and underline their pathogenetic role. Moreover, they demonstrate a partially new mechanism of HPR chemopreventive effect and indicate the potential clinical relevance of this compound for prevention of hepatocellular carcinoma.

Keywords: AAF, 2-acetylaminofluorene; AI, apoptotic index; DENA, diethylnitrosamine; FAH, foci of altered hepatocytes; GST-P, glutathione S-transferase (placental); HCC, hepatocellular carcinoma; HPR, N-(4-hydroxyphenyl)retinamide; IκB-α, inhibitor κB-α; LI, labeling index; Mat, methionine adenosyl transferase; NF-κB, nuclear factor κB; SAM, S-adenosyl-l-methionine; SL, stabilized liposomes

Journal Article.  8650 words.  Illustrated.

Subjects: Clinical Cytogenetics and Molecular Genetics

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