engleski

The expression of p53/p73 isoforms, NME and GLI in melanoma cell lines

Although mutations of p53 occur infrequently in melanoma, p53 fails to function as a tumor suppressor. This may result from alterations in p53 family members, including the diverse isoforms of p53 and its homologue p73. Moreover, we assume that the p53 function in malignant melanoma might be altered through interactions with p53 small molecular weight and p73 isoforms, NME and GLI protein families. Therefore, we are studying the expression profiles of p53 and its potential interaction partners (p73/NME/GLI) in melanoma cell lines. The expression of p53, p73, NME and GLI gene/protein families was determined by western blot analysis and quantitative RT-PCR. Protein expression analysis has shown that p53 mutant melanoma cell lines (CHL1, Mel505, and WM983B) have higher expression of p53 isoforms in contrast to p53 wild type melanoma cell lines (A375M, LM6, Mel224, Mel501 and WM793B). Identical trend was observed with NME family of proteins. NME1 and NME2 proteins showed a several fold higher expression in p53 mutant melanoma cell lines. Protein expression analysis of p73 isoforms has shown higher expression of TA isoforms in contrast to ΔN isoforms in almost all melanoma cell lines. Proteins GLI2 and GLI3 were expressed in all melanoma cell lines, while GLI1 was expressed in only a few cell lines. Comparing the gene expression profiles in melanoma cell lines, we have found that expression of NME proteins was generally the highest compared to other two gene families in p53 mutated cell lines (CHL1, Mel505 and WM983B). GLI3 showed slightly increased expression compared with reference genes, while GLI1 was the least expressed in melanoma cell lines. Within the p53 isoforms, all α isoforms were more abundant compared with β and γ. So p53α isoform was the most strongly expressed, Δ40γ was very low, while Δ133γ was not detected in melanoma cell lines. Interestingly, we were not able to detect any p53 isoform in p53 wild type melanoma cell line LM6. Both TAp73 and ΔNp73 have shown low expression compared with reference genes. Taken all together, the expression data give us insight into the abundance of proteins of interest in melanoma cell lines for further analysis of p53 interacting partners.

p53, p73, NME, GLI, melanoma cell lines

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