BX471 hydrochloride (ZK-811752 hydrochloride) is a potent, selective non-peptide CCR1 antagonist (Ki: 1 nM for human CCR1). It shows 250-fold selectivity for CCR1 over CCR2, CCR5, and CXCR4.
Talabostat (PT100, Val-boroPro) is a potent, nonselective and orally available dipeptidyl peptidase IV (DPP-IV) inhibitor with a Ki of 0.18 nM. Talabostat is a nonselective DPP-IV inhibitor, inhibiting DPP8 9, FAP, DPP2 and some other DASH family enzymes essentially as potently as it inhibits DPP-IV[1]. Talabostat stimulates the immune system by triggering a proinflammatory form of cell death in monocytes and macrophages known as pyroptosis. The inhibition of two serine proteases, DPP8 and DPP9, activates the proprotein form of caspase-1 independent of the inflammasome adaptor ASC[2]. Talabostat competitively inhibits the dipeptidyl peptidase (DPP) activity of FAP and CD26 DPP-IV, and there is a high-affinity interaction with the catalytic site due to the formation of a complex between Ser630 624 and the boron of talabostat[3]. Talabostat can stimulate immune responses against tumors involving both the innate and adaptive branches of the immune system. In WEHI 164 fibrosarcoma and EL4 and A20 2J lymphoma models, PT-100 causes regression and rejection of tumors. The antitumor effect appears to involve tumor-specific CTL and protective immunological memory. Talabostat treatment of WEHI 164-inoculated mice increases mRNA expression of cytokines and chemokines known to promote T-cell priming and chemoattraction of T cells and innate effector cells[3]. Talabostat treated mice show significant less fibrosis and FAP expression is reduced. Upon PT100 treatment, significant differences in the MMP-12, MIP-1α, and MCP-3 mRNA expression levels in the lungs are also observed. Treatment with PT100 in this murine model of pulmonary fibrosis has an anti-fibro-proliferative effect and increases macrophage activation[4]. [1]. Connolly BA, et al. Dipeptide boronic acid inhibitors of dipeptidyl peptidase IV: determinants of potencyand in vivo efficacy and safety. J Med Chem. 2008 Oct 9;51(19):6005-13. [2]. Okondo MC, et al. DPP8 and DPP9 inhibition induces pro-caspase-1-dependent monocyte and macrophage pyroptosis. Nat Chem Biol. 2017 Jan;13(1):46-53. [3]. Adams S, et al. PT-100, a small molecule dipeptidyl peptidase inhibitor, has potent antitumor effects and augments antibody-mediated cytotoxicity via a novel immune mechanism. Cancer Res. 2004 Aug 1;64(15):5471-80. [4]. Egger C, et al. Effects of the fibroblast activation protein inhibitor, PT100, in a murine model of pulmonary fibrosis. Eur J Pharmacol. 2017 Aug 15;809:64-72.
22(S)-hydroxy Cholesterol is a synthetic oxysterol and a modulator of the liver X receptor (LXR). [1] t prevents monocyte chemoattractant protein 1 (MCP-1) expression induced by the LXR agonist GW 3965 in primary hepatocytes and downregulates mRNA expression of the LXR target genes CD36, ACSL1, and SCD-1 in human myotubes. It decreases triacylglycerol and diacylglycerol synthesis from labeled palmitate and acetate, respectively, in human myoblasts by 50% when used at a concentration of 10 uM. 22(S)-hydroxy Cholesterol also reduces fatty acid synthase (FAS) reporter activity through an LXR response element in the promoter region in COS-1 cells transfected with RXRα and LXRα and decreases the expression of MCP-1 and CCR2 in a mouse model of chronic ethanol consumption.[1] [2] Dietary supplementation of 22(S)-hydroxy cholesterol (30 mg kg per day) leads to less body weight gain and lower liver triacylglycerol levels in rats when fed either a regular chow or high-fat diet as well as prevents an increase in plasma triacylglycerol levels resulting from a high-fat diet.[3]