The present study aimed to investigate the therapeutic efficacy of combining
vascular endothelial growth factor (
VEGF) receptor blockade using
tyrosine kinase inhibitor PTK787 with
hypoxia for the treatment of
hepatocellular carcinoma (HCC). The in vivo effects of the treatments were determined in a rat orthotopic HCC model, in which
hypoxia was generated by hepatic artery
ligation (HAL). Compared with HAL alone,
PTK787 combined with HAL significantly prolonged the animal survival, reduced the
tumor size, induced more
tumor tissue
necrosis and apoptosis, and down-regulated the expression of
von Willebrand factor. The mechanism was explored in vitro using murine HCC and endothelial cell lines, respectively.
PTK787 combined with
hypoxia decreased the expression of
VEGF and
VEGF receptors in both cell lines and suppressed the cell viability by induction of cell cycle arrest and promotion of apoptosis. Up-regulation of cleaved form
caspase-9 and down-regulation of Bcl-2 and
cyclin D1 were detected with the combined treatment.
Hypoxia sensitized endothelial cells to the inhibitory effect of
PTK787 on forming tubular-like structure. The motility of
tumor cells was inhibited by
hypoxia and the combined approach, with down-regulation of Rac1, Rho, and phosphorylated Akt expression. However, in the endothelial cells, the combined treatment inhibited the
hypoxia-enhanced cell motility, with suppressed Rac1, Rho, and phosphorylated Akt expression. In conclusion,
PTK787 combined with
hypoxia achieved a better therapeutic efficacy than
hypoxia alone through enhancing
hypoxia-induced antitumor cell effect and preventing the activation of angiogenic process.