Non-mitogenic FGF2 protects cardiomyocytes from acute doxorubicin-induced toxicity independently of the protein kinase CK2/heme oxygenase-1 pathway

Doxorubicin (Dox)-induced cardiotoxicity, a limiting factor in the use of Dox to treat cancer, can be mitigated by the mitogenic factor FGF2 in vitro, via a heme oxygenase 1 (HO-1)-dependent pathway. HO-1 upregulation was reported to require protein kinase CK2 activity. We show that a mutant non-mitogenic FGF2 (S117A-FGF2), which does not activate CK2, is cardioprotective against acute cardiac ischemic injury. We now investigate the potential of S117A-FGF2 to protect cardiomyocytes against acute Dox injury and decrease Dox-induced upregulation of oxidized phospholipids. The roles of CK2 and HO-1 in cardiomyocyte protection are also addressed. Rat neonatal cardiomyocyte cultures were used as an established in vitro model of acute Dox toxicity. Pretreatment with S117A-FGF2 protected against Dox-induced: oxidative stress; upregulation of fragmented and non-fragmented oxidized phosphatidylcholine species, measured by LC/MS/MS; and cardiomyocyte injury and cell death measured by LDH release and a live-dead assay. CK2 inhibitors (TBB and Ellagic acid), did not affect protection by S117A-FGF2 but prevented protection by mitogenic FGF2. Furthermore, protection by S117A-FGF2, unlike that of FGF2, was not prevented by HO-1 inhibitors and S117A-FGF2 did not upregulate HO-1. Protection by S117A-FGF2 required the activity of FGF receptor 1 and ERK. We conclude that mitogenic and non-mitogenic FGF2 protect from acute Dox toxicity by common (FGFR1) and distinct, CK2/HO-1- dependent or CK2/HO-1-independent (respectively), pathways. Non-mitogenic FGF2 merits further consideration as a preventative treatment against Dox cardiotoxicity. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00441-018-2905-z) contains supplementary material, which is available to authorized users.