Toxicogenomics of Kojic Acid on Gene Expression Profiling of A375 Human Malignant Melanoma Cells

Abstract

Kojic acid is a natural product and normally used as a food additive and preservative, a skin-whitening agent in cosmetics, a plant growth regulator and a chemical intermediate. Using DNA microarray technology, the overall biological effects of kojic acid on the gene expression profiling of a human skin A375 malignant melanoma cells were examined. After treatment with kojic acid, a total of 361 differentially expressed genes were distinctively changed with 136 up-regulated genes and 225 down-regulated genes. We used the bioinformatics tool to search the gene ontology and category classification of differentially expressed genes that provided the useful information of expressed genes belonging to cellular component, molecular function and biological process in regulation of melanogenesis. Seven down-regulated genes of APOBEC1, ARHGEF16, CD22, FGFR3, GALNT1, UNC5C and ZNF146 that were typically validated by the real-time quantitative PCR (RT-qPCR) analysis technology showed to be the tumor suppressor genes in melanoma cancer cells. Thus, microarray technology coupled with RT-qPCR offered a high throughput method to explore the number of differentially expressed genes responding to kojic acid and their biological functions, and led to more understanding of kojic acid effects on skin cancer therapy and related side effects. Moreover, the differentially expressed genes may become useful markers of skin malignant melanoma for further diagnostic and therapeutic applications.

Molecular Profiling of A375 Human Malignant Melanoma Cells Treated with Kojic Acid and Arbutin

“…The selected genes were validated by RT-qPCR analysis to confirm the microarray data. RT-qPCR results showed the gene expression levels of seven expressed genes in kojic acidstimulated A375 melanoma cells agreed with the DNA microarray expression data 18 . One gene chosen for RT-qPCR examination was the apolipoprotein B RNA editing deaminase (APOBEC1) gene 25 .…”

“…However, we will further study the effects of kojic acid on biological and molecular mechanisms in human melanoma skin cells, including in other parts of the body, and also examine other biological functions of kojic acid in its cosmetic and/or therapeutic applications. We also examined the effect of different arbutin concentrations on the growth inhibition of A375 melanoma cells and found that the concentrations used did not strongly inhibit cell growth, even though the incubation time was up to 72 h. We used 8 μg/ml (0.8% w/v) arbutin because (i) this was the same concentration of kojic acid used 18 , because this concentration was lower than the safety recommendation of 1% in prescription human skin care products 36 ; (ii) this concentration inhibited cell growth less than 10% with no morphological change of cells; and (iii) it avoids changes in gene expression data resulting from the cell death response due to cytotoxicity from a high concentration of arbutin. Therefore, 8 μg/ml arbutin, which is safe for use on human skin, was used to study the genotoxic effect on the gene expression profile of A375 melanoma cells and for examining the differential gene expression and other side effects of altered signaling pathways for cancer therapy.…”

“…The microarray results showed different fluorescence intensities of Cy3 and Cy5 depending on the gene expression level 18 .…”

“…However, only a few such analyses have been reported in A375 melanoma cells. For example, the metastasis of A375 melanoma cells has been studied in nude mice by microarray analysis 18 . Proteomics is the study of the proteome, the protein complement of the genome.…”

“…Toxicogenomic analysis of kojic acid-treated A375 melanoma cells 2.1 Inhibitory effect of kojic acid on A375 melanoma cells Previous examination showed that cell growth of A375 melanoma cells was directly inhibited by increasing kojic acid concentrations 18 . After treatment with kojic acid for 72 h, the highest concentration of kojic acid (1000 μg/ml) inhibited A375 melanoma cell growth less than 40%, whereas the lower concentrations of 0.32, 1.6, 8 and 40 μg/ml kojic acid inhibited A375 melanoma cell growth less than 20% (Fig.…”