Dietary PUFA modulate the expression of proliferation and differen markers in Morris 3924A hepatoma cells Alba Vecchini a , Veronica Ceccarelli a , Giuseppe Nocentini b , Carlo Riccardi b , Paolo Di Nardo c , Luciano Binaglia a, * a Department of Internal Medicine, Section of Biochemistry, University of Perugia, Via del Giochetto, 3, 06126 Perugia, Italy b Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Perugia, Via del Giochetto, 3, 06126 Perugia, Italy c Department of Internal Medicine, II University of Roma Tor Vergata, Via di Tor Vergata, 135,Roma, Italy Received 17 August 2005; received in revised form 28 October 2005; accepted 31 October 2005 Available online 8 November 2005 Abstract The effect of dietary polyunsaturated fatty acids on the expression of differentiation and proliferation markers in Morris 39 was investigated. ACT/I rats were conditioned 10 days with diets enriched with linoleic acid or a-linolenic acid before subcuta celltransplantation. After 19 days from the inoculum, the mRNA levels of liver-enriched transcription factors and of their target genes were quantified. Both linoleic acid- and linolenic acid-enriched diets induced a decrease of h-actin, AFP, PCNA, c-myc and of hepatocyte nuclear factors HNF-1a and HNF-4a mRNA levels in tumor tissue whereas HNF-3h expression was induced by both dietary treatments Only the a- linolenic acid-enriched diet was effective in reducing c-jun and increasing albumin mRNA levels. Since albumin is a C/EBPa target gene, C/ EBPa gene transcription was evaluated at both protein and mRNA levels. It was found that a-linolenic acid-enriched diet did n EBPa mRNA content in hepatoma tissue while inducing C/EBPa protein expression with an isoform pattern similar to the hepa This evidence implies that a-linolenic acid or one of its metabolic products induce albumin synthesis in hepatoma cells by m gene expression at post-transcriptional level. D 2005 Elsevier B.V. All rights reserved. Keywords: Hepatocyte nuclear factor; CCAAT enhancer-binding protein; a-fetoprotein; PCNA; c-myc; h-actin 1. Introduction In the present work evidence is reported that dietary lipids modulate the expression of genes involved in differentiation and proliferationof hepatocarcinoma cells. A hint for investigating on this role of lipids originated from previous observations indicating that h-actin mRNA levels significantly decrease in Morris 3924A hepatoma cells grown in rats on PUFA-enriched diets [1]. Since h-actin overexpression is a generic indicator of rapid cell proliferation, the potential role of dietary lipids in the expression of genes encoding more specific tumor cell proliferation and differentiation markers [2 – 8] was evaluated. In addition, since the promoter regions of the same genes contain consensus sequences that bind members of the heterogeneous family ofliver enriched transcription factors (LETFs), the effect of dietary lipids on LETFs expression and activity was also investigated. LETFs play important roles in liver development and differentiation [9,10], by participating in a complicated hierarchical network regulating the expression of liver-spec genesand the transcription of each other [11].At present, CCAAT enhancer-binding protein alpha (C/EBPa) and hepa- tocytenuclearfactorsHNF-1a, HNF-4a and HNF-3h are considered to be key-members of this network. CCAAT/enhancer-binding proteins C/EBPa, C/EBPh,and C/EBPy are involvedin differentiation and proliferation processes, theirspecificroleslargely depending on tissue and celltype [12,13]. C/EBPa is highly expressed in liver, whereit transactivates hepatocyte-specific genes,induces differentiationandinhibitshepatocyteproliferation [10] 1388-1981/$ - see front matter D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.bbalip.2005.10.008 * Corresponding author. Tel.: +39 075 5857489; fax: +39 075 5857428. E-mail address: binaglia@unipg.it (L. Binaglia). Biochimica et Biophysica Acta 1737 (2005) 138 – 144 http://www.elsevier.com/locate/bba