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* = Presenting author

P105 Inhibition of cytokine release from HT-29 cells and ulcerative colitis biopsies is potentiated by combination of selective kinase inhibitors, and such effects are mimicked by TOP1210, a narrow spectrum kinase inhibitor

M. R. Foster*1, P. Biancheri2, S. Sirohi1, Y. Solanke1, 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

Background

Intracellular kinase activation in mucosal immune cells plays a pivotal role in intestinal inflammation, and kinase inhibitors have been proposed as potential therapies in inflammatory bowel disease. A number of kinase inhibitors have been developed, including selective inhibitors of p38, Syk and Src kinases. In an attempt to improve efficacy, targeted multi-kinase inhibitors have been developed as exemplified by TOP1210, a narrow spectrum kinase inhibitor (NSKI). In this study, the inhibitory effects of multi-kinase inhibition by either selective kinase inhibitors in combination or TOP1210 have been tested and compared with those of selective kinase inhibitors alone.

Methods

BIRB-796, dasatinib and BAY-61-3606 were used as selective inhibitors of p38, Src and Syk, respectively, and TOP1210 as an exemplar NSKI. Compounds were assessed for their ability to inhibit IL-8 secretion from IL-1β stimulated HT-29 cells, an epithelial cell line, and spontaneous cytokine release from inflamed mucosal biopsies from ulcerative colitis (UC) patients. TOP1210 kinase inhibition was assessed using ZLYTE™ based kinase assay.

Results

Individually, the selective kinases were only weakly active as inhibitors of HT-29 IL-8 release; BIRB-796 achieved a maximal effect of approximately 35% inhibition with an IC 50 of > 1 μg/ml. Similarly, both dasatinib and BAY-61-3606 achieved only a maximum of 10%–20% IL-8 inhibition at 1 μg/ml. Generally, combination treatments resulted in significantly potentiated inhibitory effects. Combination of BIRB-796, dasatinib and BAY-61-3606 caused > 60% inhibition of IL-8 release with 100–1 000 fold leftward shifts of the BIRB-796 concentration-effect curves. In addition, greater inhibitory effects on cytokine production from UC biopsies in culture were demonstrated when selective inhibitors were used in combination compared with their use individually. TOP1210, which inhibits p38, Src and Syk, potently inhibited IL-1β, IL-6, and IL-8 release by UC biopsies with greater efficacy than that of the individual selective kinase inhibitors and with similar efficacy to combined selective kinase inhibitors.

Conclusion

The effects of the selective kinase inhibitors in combination result in enhanced efficacy and potency of inhibition. TOP1210 mimics the inhibitory effect of combined selective kinase inhibitors in HT-29 cells and UC biopsies. These data demonstrate that NSKIs, through targeted multi-kinase inhibition, have potent and efficacious cellular effects, mimicking the potentiated effects seen with combinations of selective inhibitors. This highlights the potential of multikinase inhibition as an anti-inflammatory therapy.