Cotargeting of VEGFR-1 and-3 and angiopoietin receptor Tie2 reduces the growth of solid human ovarian cancer in mice

Despite optimal surgery and chemotherapy, the prognosis of ovarian cancer patients remains poor and new treatments are urgently needed. Solid tumors require the formation of new vessels for growth and metastasis. In the present study, we have used soluble vascular endothelial growth factor (sVEGF) receptors sVEGFR-1 and -3, soluble receptors Tie1 and Tie2 and their combinations in an ovarian cancer xenograft model. Human ovarian cancer cells were injected intraperitoneally into nude mice (n = 42) and magnetic resonance imaging (MRI) was used for confirming tumors before gene delivery. Treatment with combined AdsVEGFR-1, AdsVEGFR-3 and AdsTie2 significantly decreased the size of the intraperitoneal tumors compared with the controls (AdLacZ; P = 0.038) with significantly less microvessels and vascular area. Unexpectedly, treatment with combined AdsTie1 and AdsTie2 led to a dramatic shortening of the survival which was not observed in the groups receiving either of the soluble receptors alone (P = 0.031). The only difference to other treatments was liver toxicity observed after the combined Tie receptor treatment. In conclusion, combined inhibition of VEGFR-1, VEGFR-3 and Tie2 pathways was safe and provided efficient therapy for ovarian cancer in mice. Cancer Gene Therapy (2011) 18, 100-109; doi: 10.1038/cgt.2010.56; published online 24 September 2010