The PI3K pathway as a therapeutic intervention point in inflammatory bowel disease.

With glucose being the preferred source of energy in activated T cells, targeting glycolysis has become an attractive therapeutic intervention point for chronic inflammatory bowel diseases (IBD). The switch to glycolysis is mediated by phosphoinositide-3-kinases (PI3K) which relay signals from surface receptors to the AKT pathway. We first confirmed by analysis of the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) that metabolism is shifted towards glycolysis in IBD patients as compared to non-IBD donors. In contrast to non-IBD donors, OCR correlated with ECAR (IBD: cor = 0.79, p = 2E-10; non-IBD: cor = 0.37, p = n.s.), in IBD patients. Second, we tested the PI3K inhibitor copanlisib as a potential therapeutic. Ex vivo, copanlisib suppressed the ECAR significantly in T cells activated by anti-CD3 antibodies and significantly decreased ECAR rates in the presence of copanlisib (anti-CD3: 58.24 ± 29.06; copanlisib: 43.16 ± 20.23, p < .000. In addition, copanlisib impaired the activation of CD4 CD25 T cells (anti-CD3: 42.15 ± 21.46; anti-CD3 + copanlisib: 26.06 ± 21.82 p = .013) and the secretion of cytokines (IFNγ: anti-CD3: 6332.0 ± 5707.61 pmol/ml; anti-CD3 + copanlisib: 6332.0 ± 5707.61, p = .018). In vivo, copanlisib significantly improved the histological scores (ethanol: 8.5 ± 3.81; copanlisib: 4.57 ± 2.82, p = .006) in the NSG-UC mouse model. Orthogonal partial least square analysis confirmed the efficacy of copanlisib. These data suggest that the PI3K pathway provides an attractive therapeutic intervention point in IBD for patients in relapse. Targeting metabolic pathways have the potential to develop phase dependent therapies.