Figure 4.

Triptolide and VNP20009 Synergistically Inhibit the Tumour Angiogenisis by Suppressing the Production of VEGF. A) Immunohistochemistry of CD31⁺ cells and VEGF expression in melanoma tumours from mice receiving triptolide and/or VNP20009 (VNP) treatments on d 7 post infection. CD31⁺ cells are indicated by red arrows. Bars on VEGF sections represent 10 μm. B) The quantification of CD31⁺ microvessels in tumours. Two sections per tumour were determined and four tumours were harvested in each group. The number of the CD31⁺ cells was calculated. Mean ± S.D., n=8. C) VEGF expression in melanoma tumours was examined by RT-PCR. D) ELISA assays were performed to determine VEGF concentration in tumours. Mean ± S.D., n=4. E) The treatment schedule of the combination therapy of VNP and VEGF neutralizing antibody, and its effect on the growth of tumours. The VEGF neutralizing antibody (10 μg/ tumour) or the IgG control antibody (10 μg/ tumour) were injected directly into the tumours three times on d 7, 9 and 10. VNP was intraperitoneally injected on d 8 post tumour inoculation. Mean ± S.D., n=5. F) The bacterial colonization in the tumours was determined on d 5 post VNP infection in the VEGF neutralization assay. Mean ± S.D., n=5.