Small molecule kinase inhibitors block the ZAK-dependent inflammatory effects of doxorubicin.

The adverse side effects of doxorubicin, including cardiotoxicity and cancer treatment-related fatigue, have been associated with inflammatory cytokines, many of which are regulated by mitogen-activated protein kinases (MAPKs). ZAK is an upstream kinase of the MAPK cascade. Using mouse primary macrophages cultured from ZAK-deficient mice, we demonstrated that ZAK is required for the activation of JNK and p38 MAPK by doxorubicin. Nilotinib, ponatinib and sorafenib strongly suppressed doxorubicin-mediated phosphorylation of JNK and p38 MAPK. In addition, these small molecule kinase inhibitors blocked the expression of IL-1β, IL-6 and CXCL1 RNA and the production of these proteins. Co-administration of nilotinib and doxorubicin to mice decreased the expression of IL-1β RNA in the liver and suppressed the level of IL-6 protein in the serum compared with mice that were injected with doxorubicin alone. Therefore, by reducing the production of inflammatory mediators, the inhibitors identified in the current study may be useful in minimizing the side effects of doxorubicin and potentially other chemotherapeutic drugs.