Fig. 6

SIRT2 transcription in silico analysis and in vitro activity assay. a. SIRT2 in vitro activity upon NAM treatment. The activity was measured with the SIRT2 Inhibitor Screening Assay Kit (Fluorometric) (BioVision), as reported in Methods section. After 1 h incubation at 37 °C, the in vitro activity was found to be reduced by NAM in a dose-dependent manner. b: Expression level of SIRT2 in melanoma vs normal skin, according to “Pan-Cancer Analysis of Whole Genomes” reported by the Expression Atlas at EBI [42] (https://www.ebi.ac.uk/gxa/home). SIRT2 expression is strongly increased in melanoma as compared to control skin. c. The expression level of SIRT2 in NCI-60 human cancer cells lines, from GEO dataset GDS1761. Melanoma shows the highest median expression of SIRT2, according to the expression values in 8 human cell lines (namely LOXIMVI, M14, MALME-3 M, SK-MEL-28, SK-MEL-2, SK-MEL-5, UACC257, UACC62). Box & whisker plot reports median and 5–95 percentile. d. Overall survival in melanoma patients as a function of SIRT2 expression, according to expression data reported in GEPIA2 database; overall survival is computed from quartile distribution (the cutoff for high expression was set to 70%; cutoff for low expression set to 25%). Significant improvement of overall survival is observed in patients expressing low-levels of SIRT2 (HR = 1.9, p = 0.0004)