Differential expression analysis by gene array of cell cycle modulatorsin human corneal epithelial cells stimulated with epidermal growth factor(EGF), hepatocyte growth factor (HGF), or keratinocyte growth factor (KGF).

Purpose. To identify and differentiate cell cycle and differentiationgenes that are up-regulated or down-regulated in human corneal epithelialcells in response to alternative epithelium-modulating cytokines epidermalgrowth factor (EGF), hepatocyte growth factor (HGF) or keratinocyte growthfactor (KGF). Methods. Primary cultures human corneal epithelial cell (HCE)were treated with 25 ng/ml of EGF, 25 ng/ml HGF, 25 ng/ml KGF, or vehiclefor 8 hours. Complementary DNA (cDNA) probes were synthesized from total cellularRNA isolated from the HCE cells. The cDNA probes were hybridized to the Atlashuman cell cycle/differentiation array membrane. RNAse protection assay wasused to confirm up-regulation of the serine/threonine-protein kinase PITALREgene by EGF, KGF, and HGF. Results. The expression of one hundred and eleven cell cycle anddifferentiation genes was monitored with the gene array system. It was foundthat these epithelial cell-modulating cytokines shared similar effects onsome of the cell cycle and differentiation genes that were monitored, buthad specific effects on some cytokines. Up-regulation of PITALRE gene expressionwas confirmed using RNAse protection assay. Conclusion. EGF, HGF and KGF had differential effects on cellcycle- and differentiation-related gene expression in corneal epithelial cells.For example, all three mitogenic growth factors up-regulated the expressionof cyclin D1 (BCL-1 oncogene) and serine/threonine-protein kinase PITALREin the primary cultured human corneal epithelial cells. However, EGF and KGF,but not HGF, up-regulated expression of the E2F-1 pRB-binding protein gene.Thus, while these three epithelial mitogens have similar effects on many genesthat were analyzed, important differences were noted that may relate to differingeffects of these growth factors on corneal epithelial cells. Studies to analyzethe significance of the identified differences among these growth factorsare in progress. [ABSTRACT FROM AUTHOR]