GRP78/Dna K Is a Target for Nexavar/Stivarga/Votrient in the Treatment of Human Malignancies, Viral Infections and Bacterial Diseases

Prior tumor cell studies have shown that the drugs sorafenib (Nexavar) and regorafenib (Stivarga) reduce expression of the chaperone GRP78. Sorafenib/regorafenib and the multi‐kinase inhibitor pazopanib (Votrient) interacted with sildenafil (Viagra) to further rapidly reduce GRP78 levels in eukaryotes and as single agents to reduce Dna K levels in prokaryotes. Similar data were obtained in tumor cells in vitro and in drug‐treated mice for: HSP70, mitochondrial HSP70, HSP60, HSP56, HSP40, HSP10, and cyclophilin A. Prolonged ‘rafenib/sildenafil treatment killed tumor cells and also rapidly decreased the expression of: the drug efflux pumps ABCB1 and ABCG2; and NPC1 and NTCP, receptors for Ebola/Hepatitis A and B viruses, respectively. Pre‐treatment with the ‘Rafenib/sildenafil combination reduced expression of the Coxsackie and Adenovirus receptor in parallel with it also reducing the ability of a serotype 5 Adenovirus or Coxsackie virus B4 to infect and to reproduce. Sorafenib/pazopanib and sildenafil was much more potent than sorafenib/pazopanib as single agents at preventing Adenovirus, Mumps, Chikungunya, Dengue, Rabies, West Nile, Yellow Fever, and Enterovirus 71 infection and reproduction. ‘Rafenib drugs/pazopanib as single agents killed laboratory generated antibiotic resistant E. coli which was associated with reduced Dna K and Rec A expression. Marginally toxic doses of ‘Rafenib drugs/pazopanib restored antibiotic sensitivity in pan‐antibiotic resistant bacteria including multiple strains of bla (kpc) Klebsiella pneumoniae. Thus, Dna K is an antibiotic target for sorafenib, and inhibition of GRP78/Dna K has therapeutic utility for cancer and for bacterial and viral infections. J. Cell. Physiol. 230: 2552–2578, 2015. © 2015 The Authors. Journal of Cellular Physiology published by Wiley Periodicals, Inc.