ABSTRACT
BACKGROUND/AIM: The insulin-like growth factor 1 (IGF1) signaling pathway as an aging mechanism related to p53 in human melanogenesis remains unclear. The aim of this study was to investigate the relationship between p53 and IGF1 signaling pathway in young, senescent and H2O2-treated cells. MATERIALS AND METHODS: The protein and gene expression in young, senescent and H2O2-treated cells were analyzed using western blot and reverse transcription polymerase chain reaction (RT-PCR) assays, respectively. RESULTS: The expression levels of (phosphoinositide 3-kinases) PI3K, v-akt murine thymoma viral oncogene homolog 1 (AKT1), mammalian target of rapamycin, ß-catenin (CTNNB1), acetylated p53 (ac-p53), p53 and p-p21 proteins, related to IGF1 and p53 signaling pathways, were higher in senescent and H2O2-treated cells than those of young cells. Furthermore, AKT reduced melanogenesis through microphthalmia-associated transcription factor (MITF) inactivation by the inhibition of CTNNB1. The gene expression levels of PI3K, TP53 and catalase (CAT) in senescent and H2O2-treated cells were increased compared to young cells. CONCLUSION: p53 protein plays a key role in the aging of melanocytes via IGF1 signaling pathways.
Subject(s)
Aging/genetics , Cell Proliferation/genetics , Insulin-Like Growth Factor I/genetics , Tumor Suppressor Protein p53/genetics , Aging/metabolism , Aging/pathology , Animals , Catalase/genetics , Cell Proliferation/drug effects , Cellular Senescence/genetics , Gene Expression Regulation/drug effects , Humans , Hydrogen Peroxide/toxicity , Melanocytes/metabolism , Melanocytes/pathology , Mice , Microphthalmia-Associated Transcription Factor/genetics , Phosphatidylinositol 3-Kinases/genetics , Proto-Oncogene Proteins c-akt/genetics , Signal Transduction/drug effects , beta Catenin/antagonists & inhibitors , beta Catenin/geneticsABSTRACT
The purpose of this study is to investigate the effect of H2O2 on the aging of melanogenesis in human melanocytes. The staining of SA-ß-galactosidase, an aging marker, was remarkably increased in the cells aged with H2O2 at 62.5 µM or more compared with young cells. The intracellular H2O2 level and melanin synthesis were also reduced in both H2O2-treated cells and senescent cells compared with young cells in DCFH-DA assay. Both the senescent cells and the H2O2-treated cells showed higher expression level of Catalase than young cells in western blot and immunofluorescence staining. Furthermore, the expression levels of TRP-1, TRP-2 and p300 were reduced in both senescent cells and the H2O2-treated cells, but that of SIRT-1 was inverted compared with young cells. In addition, H2O2 reduced the expression level of MITF but increased that of Nrf2 in nucleus. Those results indicate that the expression levels of antioxidant enzymes in senescent cells and H2O2-treated cell are upregulated, but the expression levels of proteins involved in melanin synthesis are downregulated. Above findings suggest that H2O2 could play a key role in the aging process of melanogenesis through modulation of MITF and Nrf2.
