Disruption of angiogenesis and tumor growth with an orally active drug that stabilizes the inactive state of PDGFRbeta/B-RAF.
Kinases are known to regulate fundamental processes in cancer including tumor proliferation, metastasis, neovascularization, and chemoresistance. Accordingly, kinase inhibitors have been a major focus of drug development, and several kinase inhibitors are now approved for various cancer indications. Typically, kinase inhibitors are selected via high-throughput screening using catalytic kinase domains at low ATP concentration, and this process often yields ATP mimetics that lack specificity and/or function poorly in cells where ATP levels are high. Molecules targeting the allosteric site in the inactive kinase conformation (type II inhibitors) provide an alternative for developing selective inhibitors that are physiologically active. By applying a rational design approach using a constrained amino-triazole scaffold predicted to stabilize kinases in the inactive state, we generated a series of selective type II inhibitors of PDGFRbeta and B-RAF, important targets for pericyte recruitment and endothelial cell survival, respectively. These molecules were designed in silico and screened for antivascular activity in both cell-based models and a Tg(fli1-EGFP) zebrafish embryogenesis model. Dual inhibition of PDGFRbeta and B-RAF cellular signaling demonstrated synergistic antiangiogenic activity in both zebrafish and murine models of angiogenesis, and a combination of previously characterized PDGFRbeta and RAF inhibitors validated the synergy. Our lead compound was selected as an orally active molecule with favorable pharmacokinetic properties which demonstrated target inhibition in vivo leading to suppression of murine orthotopic tumors in both the kidney and pancreas.
Department of Pathology, Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA.
Eric A
EA
Murphy
David J
DJ
Shields
Konstantin
K
Stoletov
Elena
E
Dneprovskaia
Michele
M
McElroy
Joshua I
JI
Greenberg
Jeff
J
Lindquist
Lisette M
LM
Acevedo
Sudarshan
S
Anand
Bharat Kumar
BK
Majeti
Igor
I
Tsigelny
Adrian
A
Saldanha
Breda
B
Walsh
Robert M
RM
Hoffman
Michael
M
Bouvet
Richard L
RL
Klemke
Peter K
PK
Vogt
Lee
L
Arnold
Wolfgang
W
Wrasidlo
David A
DA
Cheresh
D000284:Administration, Oral; D020533:Angiogenesis Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D002292:Carcinoma, Renal Cell / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects*; D007680:Kidney Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D009389:Neovascularization, Pathologic; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D048493:Proto-Oncogene Proteins B-raf / Q000378:metabolism*; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015027:Zebrafish
D020533:Angiogenesis Inhibitors; D047428:Protein Kinase Inhibitors; D020797:Receptor, Platelet-Derived Growth Factor beta; C482120:Braf protein, mouse; D048493:Proto-Oncogene Proteins B-raf