Description

Cancer

Description

KRN 633 is an ATP-competitive inhibitor of VEGFR1, VEGFR2 and VEGFR3 with IC50 of 170 nM, 160 nM and 125 nM, respectively.

Targets

IC₅₀

In Vitro

KRN 633, a novel quinazoline urea derivative, strongly inhibits VEGFR1, VEGFR2 and VEGFR3 receptors with IC50 values of 170 nM, 160 nM and 125 nM respectively. It shows lower inhibitory activity towards non-RTKs, such as PDGF receptor (PDGFRα and β, c-Kit, breast tumor kinase, and tunica interna endothelial cell kinase tyrosine kinases (IC50 = 965, 9850, 4330, 9200, and 9900 nM, respectively). KRN 633 potently inhibits ligand VEGF induced phosphorylation of VEGFR2 in HUVECs with an IC50 of 1.16 nM. KRN 633 also inhibits VEGF-dependent, but not bFGF-dependent, phosphorylation of the MAP kinases in endothelial cells, with IC50 values of 3.51 nM and 6.08 nM for ERK1 and ERK2, respectively. KRN633 has also been shown to inhibit the VEGF-driven proliferation of HUVECs with an IC50 of 14.9 nM, but it only suppresses FGF-driven proliferation at 3 μM weakly. ^[1] KRN 633 inhibits hypoxia-induced transcriptional activation of HIF-1α in a concentration-dependent manner with an IC50 of 3.79 μM, through the inhibition of both Akt and ERK phosphorylation signaling pathways. ^[2]

In Vivo

Although not cytotoxic to various cancer cells in vitro, KRN633 exhibits excellent antitumor activity in vivo due to its inhibitory effect on tumor vessel formation and vascular permeability. Once-daily administration of KRN633 at 100 mg/kg/d produces significant tumor growth inhibition in A549, LC-6-LCK, HT29, Ls174T, LNCap and Du145 cells while twice-daily administration of KRN633 at 100 mg/kg induces ~90% growth inhibition of HT29 tumors. ^[1] Treatment of mid-pregnancy mice with KRN 633 (300 mg/kg, p.o.) reduces the blood supply to fetal tissues due to diminished vascularization in both placenta and fetal organs and consequently increases the risk of induction of intrauterine growth restriction (IUGR). ^[3]

Clinical Trials

Features

Cell-Free Kinase Assays

Cell-free kinase assays are done to obtain IC50 values against a variety of recombinant VEGF receptors. KRN633 is tested at concentrations varying from 0.3 nM to 10 μM. All assays are done in quadruplicate with 1 μM ATP.

Cell Lines

A549, Ls174T, DU145, HT29, LNCap and PC-3 cell lines

Concentrations

Dissolved in DMSO, final concentrations 0.01 to 10 μM

Incubation Time

96 hours

Methods

Cancer cells are plated in media containig 10% FBS and antibiotics, at densities known to permit exponential growth over the assay period. The cells are cultured for 24 hours before adding KRN633 (0.01 to 10 μM) or just the vehicle (0.1% DMSO in medium) and then grown for a further 96 hours. Cell viability is measured using WST-1 reagent.

Animal Models

A549, Ls174T, HT29, DU145, LNCap, PC-3 cells and LC-6-JCK are established in athymic mice (BALB/cA, Jcl-nu) and athymic rats (F344/N, Jcl-rnu), respectively.

Formulation

Suspended in vehicle (0.5% methylcellulose solution)

Doses

20-100 mg/kg

Administration

Gavage once daily