Figure 1.

Hyperforin induces heme oxygenase-1 (HO-1) expression in melanoma cell lines. A375, SK-Mel-28, and FO-1 melanoma cells were treated with 2 or 3 µM of hyperforin (HPF) for 24 h. (Top) Representative immunoblots show the expression levels of HO-1, phosphorylated form of nuclear factor E2-related factor-2 (pNRF-2), heme-binding transcription factor BTB and CNC homology 1 (BACH-1), and glyceraldehyde-3-P dehydrogenase (GAPDH) after 24 h of treatment with 2 or 3 µM of HPF. (Bottom) Histograms represent the mean values ± S.D. of protein expression levels, as measured via densitometry in three independent experiments and normalized with GAPDH expression. Statistical analysis was performed using Student’s t-test for treated samples compared to the respective untreated samples after data normalization. Significance levels are denoted as follows: * p < 0.05; ** p < 0.01; *** p < 0.001.