A novel, orally active LPA₁ receptor antagonist inhibits lung fibrosis in the mouse bleomycin model

Abstract

Background and purpose: The aim of this study was to assess the potential of an antagonist selective for the lysophosphatidic acid receptor, LPA1, in treating lung fibrosis We evaluated the in vitro and in vivo pharmacological properties of the high affinity, selective, oral LPA1‐antagonist (4′‐{4‐[(R)‐1‐(2‐chloro‐phenyl)‐ethoxycarbonylamino]‐3‐methyl‐isoxazol‐5‐yl}‐biphenyl‐4‐yl)‐acetic acid (AM966). Experimental approach: The potency and selectivity of AM966 for LPA1 receptors was determined in vitro by calcium flux and cell chemotaxis assays using recombinant and native cell cultures. The in vivo efficacy of AM966 to reduce tissue injury, vascular leakage, inflammation and fibrosis was assessed at several time points in the mouse bleomycin model. Key results: AM966 was a potent antagonist of LPA1 receptors, with selectivity for this receptor over the other LPA receptors. In vitro, AM966 inhibited LPA‐stimulated intracellular calcium release (IC50= 17 nM) from Chinese hamster ovary cells stably expressing human LPA1 receptors and inhibited LPA‐induced chemotaxis (IC50= 181 nM) of human IMR‐90 lung fibroblasts expressing LPA1 receptors. AM966 demonstrated a good pharmacokinetic profile following oral dosing in mice. In the mouse, AM966 reduced lung injury, vascular leakage, inflammation and fibrosis at multiple time points following intratracheal bleomycin instillation. AM966 also decreased lactate dehydrogenase activity and tissue inhibitor of metalloproteinase‐1, transforming growth factor β1, hyaluronan and matrix metalloproteinase‐7, in bronchoalveolar lavage fluid. Conclusions and implications: These findings demonstrate that AM966 is a potent, selective, orally bioavailable LPA1 receptor antagonist that may be beneficial in treating lung injury and fibrosis, as well as other diseases that are characterized by pathological inflammation, oedema and fibrosis.

Deficiency or inhibition of lysophosphatidic acid receptor 1 protects against hyperoxia-induced lung injury in neonatal rats

“…This finding is supported by our fibrin deposition data, in which extravascular fibrin deposition depends on leakage of the plasma protein fibrinogen into the alveolar lumen and its local conversion into fibrin by thrombin (Wagenaar et al 2004). These data are in agreement with the absence of a beneficial effect of Ki16425 on LPS-induced protein accumulation in bronchoalveolar lavage fluid (Zhao et al 2011), but in contrast with beneficial effects of LPAR1 deficiency or pharmacological inhibition of bleomycin-induced vascular leakage in experimental lung fibrosis (Swaney et al 2010, Tager et al 2008). These differences in the efficacy to reduce pulmonary vascular leakage may be explained, at least in part, by differences in animal models, species, receptor antagonist, and the onset and progression of tissue damage in these models of experimental lung disease.…”

“…LPAR1 couples with three types of G proteins: Gα12/13, Gαq/11, Gαi/o, resulting in the initiation of several downstream signaling cascades: Rho-ROCK pathway, phospholipase C pathway, Ras-MAPK pathway, Akt pathway, and adenylyl cyclase inhibition . Beneficial effects of reduced LPAR1 signaling in pulmonary disease have been demonstrated in fibroblasts of patients with idiopathic pulmonary fibrosis (Tager et al 2008) and in rodents, as LPAR1 deficient mice are protected against fibrosis and mortality after bleomycin-induced pulmonary fibrosis (Tager et al 2008) and LPS-induced lung inflammation (Zhao et al 2011), and pharmacological blocking of LPAR1 protects against lung fibrosis (Swaney et al 2010) and LPS-induced lung injury (Zhao et al 2011). LPA is also a potent bronchoconstrictor, suggesting a role in airway hyperresponsiveness and asthma (Toews et al 2002).…”

Small molecule-mediated inhibition of myofibroblast transdifferentiation for the treatment of fibrosis

“…S8B). As positive controls, we used AM152, an LPA1 receptor antagonist, which acts by inhibiting fibroblast trafficking and vascular leakage (24), and pirfenidone, an FDA-approved antifibrotic drug, which has been reported to act by a number of antifibrotic mechanisms (20). CBR-096-4 (10 mg/kg) had a similar level of antifibrotic activity, as determined by histological Ashcroft scoring and automated image analysis for collagen staining (described in Methods), compared with the maximally efficacious doses of AM152 (once daily P.O.…”

Recent advances in targeting the autotaxin-lysophosphatidate-lipid phosphate phosphatase axis in vivo

“…This is a disease of interstitial infiltrates in the lungs characterized by progressive shortness of breath and worsening pulmonary function [130][131] . This process is slowed in bleomycin-induced IPF mouse models with the LPA 1 antagonist AM966 [132] . To date, there are at least three LPA 1 antagonists in phase I/II clinical trials for IPF [108,[133][134][135] (Table 1).…”

“…It was the first reported ATX inhibitor to reduce plasma LPA levels in vivo for an extended period [140] . In rat air-pouch models, 30 mg/kg PF-8380 inhibited inflammatory hyperalgesia with the same efficacy as 30 mg/kg naproxen, a routinely used nonsteroidal anti-inflammatory drug Inflammatory hyperalgesia [140] Radiotherapy sensitizer in glioblastoma [146] ONO-8430506 Autotaxin activity inhibitor (competitive) Preclinical IC 50 5 nmol/L 10-30 mg/kg Benign prostatic hyperplasia [147] Reduces breast tumor growth and metastasis and increases sensitization to doxorubicin [76,148] Lpathomab TM LPA monoclonal antibody Preclinical 25 mg/kg Traumatic brain injury [127] AM966 LPA 1 antagonist Preclinical IC 50 17 nmol/L 10 mg/kg Idiopathic pulmonary fibrosis [132] BMS-986020 LPA 1 antagonist Phase II 600 mg/day (patients) Idiopathic pulmonary fibrosis [133] BMS-986202/AM152 LPA 1 antagonist Phase I 20-40 mg/kg Idiopathic pulmonary fibrosis [134] SAR100842 LPA 1/3 antagonist Phase II 20-40 mg/kg Systemic sclerosis [135] Gene overexpression Induced LPP gene expression Preclinical Overexpressed in cancer cells LPP3 overexpression reduces ovarian cancer cell growth [118] LPP1 overexpression reduces tumor growth and metastasis in breast and thyroid cancers [116] (NSAID) [140] . At this concentration, PF-8380 maximally reduced LPA levels in both plasma and at the site of inflammation.…”