|
Research Area
|
|
Description
|
Solid tumours |
|
Biological Activity
|
|
Description
|
OSI-930 is a potent inhibitor of Kit, KDR, Flt, CSF-1R, c-Raf and Lck with IC50 of 80 nM, 9 nM, 8 nM, 15 nM, 41 nM and 22 nM, respectively. |
|
Targets
|
Kit (activated) |
KDR |
Flt1 |
CSF-1R |
c-Raf |
Lck |
|
IC50 |
80 nM |
9 nM |
8 nM |
15 nM |
41 nM |
22 nM [1] |
|
In Vitro
|
OSI-930 inhibits the cell proliferation in the HMC-1 cell line with IC50 of 14 nM without significant effect on growth of the COLO-205 cell line that does not express a constitutively active mutant receptor tyrosine kinase. Moreover, OSI-930 also induces apoptosis in HMC-1 cell line with EC50 of 34 nM. [1] A recent study shows that OSI-930 inactivates purified, recombinant cytochrome P450 (P450) 3A4 with a Ki of 24 μM in a time- and concentration-dependent mode. [2] |
|
In Vivo
|
OSI-930, administrated at the maximally efficacious dose of 200 mg/kg by oral gavage, exhibits potent antitumor activity in a broad range of preclinical xenograft models including HMC-1, NCI-SNU-5, COLO-205 and U251 xenograft models. [1] |
|
Clinical Trials
|
OSI-930 is currently in Phase I clinical trials in patients with Advanced Solid Tumors. |
|
Features
|
|
|
Combination Therapy
|
|
Description
|
Combination of OSI-930 and Erlotinib is currently in Phase I clinical trials in patients with Advanced Solid Tumors. |
|
Protocol
|
|
Kinase Assay
[1]
|
| Protein kinase assays |
Protein kinase assays are either done in-house by ELISA-based assay methods (Kit, KDR, PDGFRα, and PDGFRβ) or by a radiometric method. In-house ELISA assays used poly(Glu:Tyr) as the substrate bound to the surface of 96-well assay plates; phosphorylation is then detected using an antiphosphotyrosine antibody conjugated to HRP. The bound antibody is then quantitated using ABTS as the peroxidase substrate by measuring the absorbance at 405/490 nm. All assays uses purified recombinant kinase catalytic domains that are either expressed in insect cells or in bacteria. The Kit and EGFR protein used for in-house assays are prepared internally; other enzymes are obtained. Recombinant Kit protein is expressed as an NH2-terminal glutathione S-transferase fusion protein in insect cells and is initially purified as a nonphosphorylated (nonactivated) enzyme with a relatively high Km for ATP (400 μM). In some assays, an activated (tyrosine phosphorylated) form of the enzyme is prepared by incubation with 1 mM ATP for 1 hour at 30 °C. The phosphorylated protein is then passed through a desalting column to remove the majority of the ATP and stored at ?80 °C in buffer containing 50% glycerol. The resultant preparation has a considerably higher specific activity and a lower Km for ATP (25 μM) than the initial nonphosphorylated preparation. The inhibition of Kit autophosphorylation by OSI-930 is assayed by incubation of the nonphosphorylated enzyme at 30 °C in the presence of 200 μM ATP and various concentrations of OSI-930. The reaction is stopped by removal of aliquots into SDS-PAGE sample buffer followed by heating to 100 °C for 5 minutes. The degree of phosphorylation of Kit is then determined by immunoblotting for both total Kit and phosphorylated Kit. |
|
Cell Assay
[1]
|
| Cell Lines |
HMC-1 and COLO-205 |
| Concentrations |
0--1 μM |
| Incubation Time |
48 hours |
| Methods |
For assays of cell proliferation and apoptosis, cells are seeded into 96-well plates and incubated for 2 to 3 days in the presence of OSI-930 at various concentrations. Inhibition of cell growth is determined by luminescent quantitation of the intracellular ATP content using CellTiterGlo. Induction of caspase-dependent apoptosis by OSI-930 is quantitated by an enzymatic caspase 3/7 assay. Inhibition of angiogenesis by OSI-930 is monitored using the rat aortic ring endothelial sprout outgrowth assay. Sections of aorta are prepared from CO2-euthanized male rats and cultured in vitro in a collagen matrix in the presence or absence of OSI-930. The collagen matrix is prepared from type 1 rat tail collagen solubilized in 0.1% acetic acid at 3 mg/mL, which is combined with 0.125 volume collagen buffer (0.05 N NaOH, 200 mM HEPES, 260 mM NaHCO3), 0.125 volume of medium 199, 0.0125 volume of 1 M NaOH, and 1% GlutaMax. Aortic rings are embedded in 0.4 mL of this matrix in six-well plates, to which 0.5 mL endothelial basal medium and the appropriate amount of OSI-930 is added; the rings are then incubated for 10 days and the resultant angiogenic sprout outgrowth is digitally quantitated from images by measurement of the sprout-containing area within a series of concentric rings around the aortic tissue area. |
|
Animal Study
[1]
|
| Animal Models |
HMC-1, NCI-SNU-5, COLO-205 and U251 cells are injected s.c. into the right flank of CD1 nu/nu mice. |
| Formulation |
OSI-930 is dissolved in either Labrafil M 1944 CS or polyethylene glycol (PEG)-400/water (50:50). |
| Doses |
≤200 mg/kg |
| Administration |
Administered via p.o. |
|