Abstract

Dithranol is enormously effective in the treatment of psoriasis; however its molecular mode of action should be further elucidated. Since epidermal growth factor receptor (EGFR) is involved in the pathogenesis of psoriasis, the objective of this study was to investigate the transcriptional effect of dithranol on EGFR gene expression in the HaCaT keratinocyte cell line, which is commonly employed as a model system to study psoriasis including experiments examining the effects of therapeutic drugs and cellular regulators on keratinocytes. Cultured HaCaT cells were treated with 0.1-0.5 µg/ml dithranol for 30 min. After 4 h, total cellular RNA isolated from HaCaT cells was reverse transcribed to cDNA which was subjected to polymerase chain reaction (PCR) with specific primer pair for EGFR. We found that dithranol treatment down-regulated the EGFR mRNA of HaCaT cells in a concentration-dependent manner. Our result was further substantiated using aquantitative real-time PCR approach. Taken together, the dithranol-induced down-regulation of the EGFR in cultured human keratinocytes might help to disclose the molecular therapeutic action of the drug.

Key words: Psoriasis, dithranol, EGFR, gene expression, human keratinocytes

Abbreviation

Abbreviations: Bp, Base pairs; DNase I, deoxyribonuclease; FBS, fetal bovine serum; DMEM, dulbecco’s modified eagle’s medium; EGF, epidermal growth factor; EGFR, epidermal growth factor receptor; HB-EGF, heparin binding EGF-like growth factor; PBS, phosphate buffered saline; RT-PCR, reverse transcriptase-polymerase chain reaction; TGF-α, transforming growth factor-α; VDRE, vitamin D-responsive element.