engleski

The expression profile of p53 isoforms in healthy and melanoma tissues

The p53 protein, the “guardian of the genome”, is a transcription factor with a key role in genetic stability and therefore preventing cancer formation. The TP53 gene encodes 12 distinct isoforms of p53, able to modulate p53 activity. Some p53 isoforms have been identified in several cancers, however their function remains unclear. In melanoma, mutations of TP53 are infrequent compared to other cancers and p53 is highly expressed, suggesting a role of p53 isoforms to modulate p53 activity. In this work, protein expression of p53, p53, p53, 40p53, 133p53, 133p53 and 133p53 isoforms has been studied in vivo, by western blot, in healthy and tumor tissue samples from 25 patients with melanoma. For each p53 isoform, presence of proteins in both healthy and tumor tissue samples was compared and statistically analyzed using Student t-test. Our results show that p53 is often expressed in both healthy and tumor tissue (72 and 85%, respectively). p53, 40p53 and 133p53 have low level of expression (in less than 30% of samples). p53 and 133p53 are not expressed at all. We report that for each p53, p53, p53, 40p53, 133p53 and 133p53isoforms, there is no difference of expression between healthy and tumor tissue samples. However 133p53expression is significantly different in the two tissue types, it is poorly expressed in healthy tissue (12%), but strongly expressed in tumor tissue (72%). The 133p53 isoform, known as a dominant-negative regulator of p53 transcriptional activity, is significantly overexpressed in melanoma tissue, suggesting its potential role in inactivation of p53 tumor-suppressor activity in melanoma.

p53 ; isoforms ; melanoma ; in vivo ; protein expression

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