P218 Drug repurposing screen of Food and Drug Administration-approved medicines identifies novel anti-inflammatory and NF-kB inhibitory activity of the tyrosine kinase inhibitor sunitinib malate

Abstract Background/Aims Macrophage-mediated inflammation is a driver of both acute inflammatory responses and chronic inflammatory conditions such as rheumatoid arthritis. Drug repurposing is an attractive strategy for the development of novel anti-inflammatory therapeutics. Currently used anti-inflammatories for rheumatoid arthritis have their own risk factors, the development of small molecule anti-inflammatory drugs with decreased side effect profiles is thus an ongoing process. The aim of this study was to identify FDA-approved medicines with novel anti-inflammatory effects in macrophages. Methods A murine macrophage NF-κB reporter cell-line was used to screen a library of 159 FDA-approved medicines for NF-κB inhibition upon LPS stimulation. To investigate sunitinib malate in vitro, cytokine production in LPS-stimulated bone marrow derived macrophages treated with sunitinib malate was measured (n = 5-7) and IC50 values were calculated from resulting concentration response curves. To investigate NF-κB inhibitory effects of sunitinib malate in vivo, mice (n = 10-11 per group) dosed orally with vehicle or sunitinib malate (30mg kg-1) were exposed to a model of acute endotoxemia (1-hour intraperitoneal injection with LPS, 10mg kg-1). Statistical significance was assessed by one-way ANOVA followed by Tukey’s post-hoc test. Results Our initial screen identified 18 medicines with NF-κB inhibitory activity. Among these, the type III tyrosine kinase inhibitor sunitinib malate was further investigated and found to reduce pro-inflammatory mediator production in BMDMs (TNFα IC50=0.97μM, IL-1β IC50= 1.74μM, IL-6 IC50=1.14μM, CCL2 IC50=1.19μM, Nitrite IC50=0.59μM; n = 5-7) without compromising cell viability. In vivo, sunitinib malate significantly reduces serum TNFα (p < 0.05; one-way ANOVA; n = 10) and liver tnf mRNA expression (p < 0.01; one-way ANOVA; n = 10) in a murine model of acute endotoxemia, and reduces nuclear translocation of NF-κB compared to vehicle-treated mice (p < 0.01; one-way ANOVA; n = 7). Conclusion Screening of existing medicines in macrophages allows previously unexplored anti-inflammatory properties to be identified. Here, we have found that the tyrosine kinase inhibitor sunitinib malate has potent anti-inflammatory activity in macrophages in vitro and in vivo, mediated via an NF-κB-dependent mechanism. These results justify further exploration of sunitinib malate in macrophages and its potential as a repurposed anti-inflammatory therapeutic in arthritis. Disclosure A.C. Bowman: None. L. Chaffey: None. D. Greaves: None.