Based on preliminary data by our group suggesting an upregulation of the mitogen-activated protein kinases (MAPKs) in human lymphocytes exposed to dabrafenib and trametinib, specifically elevated expression of phosphorylated JNK (p-JNK), p38 MAPK (p-p38 MAPK), and ERK5 (p-ERK5), we hypothesized that the mechanism of MAPK pathway activation with DT therapy is similar to that reported in patients with familial Mediterranean fever (FMF), a rare, inherited condition characterized by episodes of fever and rash that responds exceedingly well to colchicine-based therapy in which the MAPK pathway is hyper-activated.
Further investigation of the molecular mechanisms revealed that FT-A treatment rapidly inhibited phosphorylation of extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK) and p38 in both yeast induced pyrexia mice and HEK 293T-TRPV1 cells.
OZ pre-treatment decreased the expression of HT-induced Bcl-2 and increased the expression of pro-apoptotic Bax, while markedly suppressed the phosphorylation of JNK and p38.
We conclude that in epithelial cells, IL-18 signal transduction is primarily via the MAPK p38 pathway rather than NF-kappaB, which may explain the absence of COX-2 and the failure of IL-18 to cause fever.