IC50: 0.3-1 μM for PDGF receptor kinase in vitro and in Swiss 3T3 cells

AG-1295 is a potent and selective inhibitor of PDGF receptor kinase.

Protein tyrosine kinase (PTK) inhibitors are potential antiproliferative agents for diseases caused by the hyperactivity of PTKs. PTK inhibitors specific for platelet-derived growth factor (PDGF) receptor kinase could help in the treatment of restenosis, pulmonary fibrosis, atherosclerosis and gliomas.

In vitro: The previous study investigated the effect of PDGF receptor-beta (PDGFR-β) inhibition by AG-1295 on the osteogenic differentiation of the mouse pre-osteoblastic cell line MC3T3-E1. Results showed that AG-1295 could significantly increase the alkaline phosphatase (ALP) activity and enhance the formation of mineralized nodules dose-dependently. Moreover, the treatment with AG-1295 led to the up-regulated mRNA expression of the osteogenic marker genes collagen type I, runt-related transcription factor 2, osterix, tissue-nonspecific alkaline phosphatase, as well as osteocalcin. Consistent with its effect on osteoblast differentiation, AG-1295 was also able to significantly suppress the phosphorylation of Erk1/2 in MC3T3-E1 cells [1].

In vivo: A previous animal study was designed to evaluated the possible effects of AG1295 on the development of interstitial fibrosis in rats with unilateral ureteral obstruction, monitored by ED-A+ fibronectin expression, the number of macrophages. Results showed that the i.p.treatment with AG1295 at 12 mg/kg could significantly reduce interstitial fibrosis as verified by a smaller Sirius-Red stained area and also by a reduced number of macrophages, and by the ED-A+ fibronectin deposition and the number of cells positive for α-smooth muscle actin [2].

Clinical trial: So far, no clinical study has been conducted.

References:
[1] Zhang YY, Cui YZ, Luan J, Zhou XY, Zhang GL, Han JX.  Platelet-derived growth factor receptor kinase inhibitor AG-1295 promotes osteoblast differentiation in MC3T3-E1 cells via the Erk pathway. Biosci Trends. 2012 Jun;6(3):130-5.
[2] Ludewig D, Kosmehl H, Sommer M, Bhmer FD, Stein G.  PDGF receptor kinase blocker AG1295 attenuates interstitial fibrosis in rat kidney after unilateral obstruction. Cell Tissue Res. 2000 Jan;299(1):97-103.