YM-359445, an orally bioavailable vascular endothelial growth factor receptor-2 tyrosine kinase inhibitor, has highly potent antitumor activity against established tumors.
OBJECTIVE
The vascular endothelial growth factor receptor-2 (VEGFR2) tyrosine kinase has been implicated in the pathologic angiogenesis associated with tumor growth. YM-359445 was a (3Z)-3-quinolin-2(1H)-ylidene-1,3-dihydro-2H-indol-2-one derivative found while screening based on the inhibition of VEGFR2 tyrosine kinase. The aim of this study was to analyze the efficacy of this compound both in vitro and in vivo.


METHODS
We tested the effects of YM-359445 on VEGFR2 tyrosine kinase activity, cell proliferation, and angiogenesis. The antitumor activity of YM-359445 was also tested in nude mice bearing various established tumors and compared with other VEGFR2 tyrosine kinase inhibitors (ZD6474, CP-547632, CGP79787, SU11248, and AZD2171), a cytotoxic agent (paclitaxel), and an epidermal growth factor receptor tyrosine kinase inhibitor (gefitinib).


RESULTS
The IC50 of YM-359445 for VEGFR2 tyrosine kinase was 0.0085 micromol/L. In human vascular endothelial cells, the compound inhibited VEGF-dependent proliferation, VEGFR2 autophosphorylation, and sprout formation at concentrations of 0.001 to 0.003 micromol/L. These concentrations had no direct cytotoxic effect on cancer cells. In mice bearing various established tumors, including paclitaxel-resistant tumors, once daily oral administration of YM-359445 at doses of 0.5 to 4 mg/kg not only inhibited tumor growth but also reduced its vasculature. YM-359445 had greater antitumor activity than other VEGFR2 tyrosine kinase inhibitors. Moreover, in human lung cancer A549 xenografts, YM-359445 markedly regressed the tumors (73%) at a dose of 4 mg/kg, whereas gefitinib caused no regression even at 100 mg/kg.


CONCLUSIONS
Our results show that YM-359445 is more potent than orally bioavailable VEGFR2 tyrosine kinase inhibitors, which leads to great expectations for clinical applicability.
Pharmacology Laboratories, Molecular Medicine Laboratories, Yamanouchi Pharmaceutical Co. Ltd., Tsukuba, Japan. nobuaki.amino@jp.astellas.com
Nobuaki
N
Amino
Yukitaka
Y
Ideyama
Mayumi
M
Yamano
Sadao
S
Kuromitsu
Katsuinori
K
Tajinda
Kiyohiro
K
Samizu
Hiroyuki
H
Hisamichi
Akira
A
Matsuhisa
Kenna
K
Shirasuna
Masafumi
M
Kudoh
Masayuki
M
Shibasaki
D000284:Administration, Oral; D020533:Angiogenesis Inhibitors / Q000627:therapeutic use*; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use; D001682:Biological Availability; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm; D005260:Female; D000077156:Gefitinib; D006801:Humans; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008819:Mice, Nude; D015394:Molecular Structure; D009369:Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000517:prevention & control; D017239:Paclitaxel / Q000627:therapeutic use; D010766:Phosphorylation / Q000187:drug effects; D010879:Piperazines / Q000627:therapeutic use*; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use*; D011799:Quinazolines / Q000627:therapeutic use; D013844:Thiazoles / Q000627:therapeutic use*; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
D020533:Angiogenesis Inhibitors; D000972:Antineoplastic Agents, Phytogenic; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D013844:Thiazoles; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C509950:YM-359445; C467480:vascular endothelial growth factor A, mouse; D040301:Vascular Endothelial Growth Factor Receptor-2; D017239:Paclitaxel; D000077156:Gefitinib