P100 Effects of a narrow spectrum kinase inhibitor and selective kinase inhibitors on the intestinal pro-inflammatory immune response in ulcerative colitis
M. R. Foster*1, P. Biancheri2, Y. Solanke1, S. Sirohi1, M. C. Fyfe1, A. Rowley1, T. T. MacDonald2, E. Wood3, S. Webber1, C. A. Walshe1
1Topivert Pharma Ltd, London, United Kingdom, 2Barts and the London, School of medicine and dentistry, London, United Kingdom, 3Homerton University Hospital, Academic Department of Medical and Surgical Gastroenterology, London, United Kingdom
Intracellular kinase activation plays a key role in inflammation and kinase inhibitors have been proposed as potential therapies in chronic inflammatory disorders. Selective kinase inhibitors, however, have proved disappointing, particularly in treatment of rheumatoid arthritis and inflammatory bowel disease (IBD). Here, multi-kinase inhibition with a narrow spectrum kinase inhibitor (NSKI), TOP1210, has been investigated as a strategy to improve efficacy. In particular, the activity of TOP1210 has been compared with selective kinase inhibitors (BIRB-796, dasatinib and BAY-61-3606) in a range of innate and adaptive inflammatory cell assays and in inflamed biopsies from ulcerative colitis (UC) patients.
Activity of compounds as inhibitors of purified kinases was assessed using ZLYTETM based kinase assays. Anti-inflammatory effects of TOP1210 or selective kinase inhibitors were assessed by measurement of pro-inflammatory cytokine release from peripheral blood mononuclear cells (PBMCs) from healthy donors, HT29 cells, inflamed colonic UC biopsies, and myofibroblasts isolated from inflamed colonic UC mucosa.
TOP1210 potently inhibited P38α, Src and Syk kinase activity with IC50 values of 65nM, 10nM, and 17nM, respectively. Similarly, TOP1210 demonstrated efficacious and potent inhibitory activity (IC50 values range, 1.8–37 nM) against pro-inflammatory cytokine release from PBMCs from healthy donors, primary macrophages and HT29 epithelial cells. In each cell type, TOP1210 achieved complete inhibition, regardless of cytokine measured or stimulus used. Generally, the selective kinase inhibitors showed limited efficacy and much weaker potency in the cellular assays compared with the broad inhibitory profile of TOP1210. Additionally, TOP1210 down regulated the spontaneous release of IL-1β, IL-6, and IL-8 from inflamed colonic UC biopsies, and was superior in effect to the selective kinases. Similarly, TOP1210 potently inhibited IL-6 (IC50 2.2 ng ml-1) and IL-8 release (IC50 2.1 ng ml-1) from TNFα-stimulated myofibroblasts, whereas the selective kinase inhibitors were at least 150 fold less potent than TOP1210 and generally demonstrated lower efficacy.
Targeted, multi-kinase inhibition with NSKIs like TOP1210 leads to an efficacious and broad inhibitory profile in UC tissues and across a range of cell types including epithelial cells and innate and adaptive immune cells. Thus, NSKIs may provide significant advantages over existing selective kinase approaches, and potentially offer much improved therapeutic benefit in IBD.