Molecule

Description

Cancer

Description

PHA-680632 is potent inhibitor of Aurora A, Aurora B and Aurora C with IC50 of 27 nM, 135 nM and 120 nM, repectively.

Targets

IC₅₀

In Vitro

PHA-680632 potently inhibits all three Aurora kinases (A, B, and C) with IC50 values of 27, 135, and 120 nM, respectively. PHA-680632 is selective for Aurora kinases, with 10- to 200-fold higher IC50 for FGFR1, FLT3, LCK, PLK1, STLK2, VEGFR2, and VEGFR3, and with IC50 higher than 10 μM for another 22 kinases. PHA-680632 shows potent anti-proliferative effects in a wide range of cell types with IC50 values of 0.06–7.15 μM, including HeLa, HCT116, HT29, LOVO, DU145, and NHDF cells. PHA-680632 (0.5 μM) causes polyploidy in tumor cells. The mechanism of action of PHA-680632 is in agreement with inhibition of Aurora kinases. ^[1]PHA680632 in association with radiation leads to additive effects in cancer cells, especially in the p53-deficient cells. Combined ionising radiation (IR) and treatment of PHA680632 (100–400 nM) prior to IR leads to an enhancement of radiation-induced Annexin V positive cells, micronuclei formation, and Brca1 foci formation only in HCT116 cells with deficient p53, other than the p53 wild-type counterparts. ^[2]

In Vivo

HA-680632 (15–60 mg/kg) inhibits tumor growth in mice xenografts models of HL60, A2780, and HCT116 cells, by reducing tumor cell proliferation and increasing apoptosis. PHA-680632 (45 mg/kg) suppresses growth of activated ras-driven mammary tumors in mouse mammary tumor virus v-Ha-ras transgenic mice and results in complete tumor stabilization and partial regression. ^[1]

Clinical Trials

Features

Aurora Kinase Inhibition Assay

Inhibition of kinase activity by PHA-680632 is assessed using a scintillation proximity assay format. The biotinylated substrate is transphosphorylated by the kinase in presence of ATP traced with γ³³-ATP. The phosphorylated substrate is then captured using streptavidin-coated scintillation proximity assay beads and the extent of phosphorylation is evaluated by β-counter after a 4-hour rest for the floatation of the beads on a dense 5 M CsCl solution. In particular, a peptide derived from the Chocktide sequence (LRRWSLGL) is used as substrate for Aurora A, whereas the optimized peptide Auroratide is employed for Aurora B and C. The assay is run in a robotized format on 96-well plates. The potency of the compound toward Aurora kinases is evaluated and IC50 values are determined.

Cell Lines

HeLa, HCT116, HT29, LOVO, DU145, and NHDF cells

Concentrations

0.001-1 μM, dissolved in DMSO as 10 mM stock solution

Incubation Time

72 hours

Methods

Cells (5×10³ to 1.5×10⁴ per cm²) are seeded in 24-well plate. After 24 hours, plates are treated with PHA-680632 and incubated for 72 hours. At the end of incubation time, cells are detached from each plate and counted using a cell counter. IC50s are calculated using percentage of growth versus untreated control.

Animal Models

Mice (female athymic nude) xenografts models of p53^?/? HCT116 cells

Formulation

Dissolved in 20% Tween-80 in 5% glucose solution

Doses

40 mg/kg

Administration

Intraperitoneal (i.p.) injection twice a day