Modulation of KGF-1 gene expression in oral fibroblasts by ripe areca nut extract

Background: Areca chewing is a common habit of Asians, leading to a high propensity for a variety of oral diseases in this population. This research aimed to study the expression level of genes in oral fibroblast cell lines in response to exposure to ripe areca nut extract (rANE). Methods: Fifteen oral fibroblast cell lines obtained from individuals aged 20-77 years were established. Treatment of a cell line with 40 mug/ml rANE for 24 h was performed to achieve RNA for cDNA microarray analysis. Results: Among some 320 genes exhibiting detectable expression levels, 14 were up-regulated and 26 were down-regulated more than 2.5-fold. Semi-quantitative RT-PCR analysis suggested that up-regulation of IL-6 expression and down-regulation of PDGFR , APP-1 and KGF-1 expressions in multiple cell lines assayed, were compatible with the results of the microarray analysis. Using quantitative real-time RT-PCR analysis, a remarkable down-regulation of KGF-1 expression in response to 40 mug/ml rANE, ranging 1.5-ninefold as compared to controls, was found in 60% (9/15) of the cell lines. Conclusion: This study established a novel toxicogenomic database for rANE. The down-regulation of KGF-1 expression in oral fibroblast cell lines potentially impairs the proliferation of overlying keratinocytes, which could partially explain the frequent epithelial atrophy observed in chronic areca chewers in vivo.