Fig. 2: TAp73α levels are reduced in MAPKi-resistant cells.

a Immunoblot analysis for p73α and p53 in different S melanoma cells after treatment with the indicated concentrations of cisplatin (CDDP) or carboplatin (CDCBA) for 24 h. Actin served as a loading control. b Left graphs: p21 mRNA expression (CDKN1A) after cisplatin (CDDP) or carboplatin (CDCBA) treatment in S melanoma cells normalized to Actin expression and to the corresponding untreated control cells (Ctr.) set as 1. Exemplary data of one experiment performed in triplicates are shown. Right graphs: Immunoblot analysis of p53 and p21 protein expression was performed in S and R melanoma cell lines with or without cisplatin treatment (5 µM) for 24 h. Actin served as a loading control. c TAp73 mRNA expression (TA TP73) in S, R and DR melanoma cell lines normalized to Actin expression and to the corresponding S cells set as 1 (Mean values ± SD; n = 3). d Detection of C-terminal p73α isoform transcript levels in S, R and DR melanoma cells. GAPDH expression was used as a control (PCR and subsequent agarose gel electrophoresis). e Immunoblot analysis of p73α protein in nuclear enriched lysate fractions (N) of S and R melanoma cells. Lamin B served as a loading control. f Published data set of mRNA sequencing performed by Hugo et al.²⁶ was used for the analysis. TP73 expression (log2 signals) in metastatic melanoma samples under MAPKi treatment was normalized to the TP73 expression in the metastases collected before treatment start from the same patient, respectively