Effects of DKK1 on gene expression on keratinocytes

Dickkopf 1 (DKK1), which is expressed at high mRNA levels by fibroblasts in the dermis of human skin on the palms and soles, inhibits the function and proliferation of melanocytes in the epidermis of those areas via the suppression of beta-catenin and microphthalmia-associated transcriptor factor (MITF). In this study, we report that treatment of keratinocytes with DKK1 increases their proliferation and decreases their uptake of melanin, and that treatment of reconstructed skin with DKK1 induces a thicker and less pigmented epidermis. We investigated the effects of DKK1 on keratinocytes using DNA microarray technology. Keywords: compound treatment design Paired cDNA samples, labeled by cyanine 3- and cyanine 5-dUTP incorporation (Qiagen, Valencia, CA) during reverse transcription (Qiagen), were hybridized simultaneously with one oligo-DNA chip (HS-Operon V2vB2.2p13) as per NCI in-house protocol. Two fluorescent intensities of the oligo-DNA chip were scanned using a microarray scanner (GenePix 4000A, Axon Instruments, Inc., Molecular Device Corp., Sunnyvale, CA).