Background/aims: Tumor necrosis factor-alpha (TNF-alpha) exerts its anti-tumor effect through direct cytotoxicity on tumor cells and damage to the tumor vasculature. However, its role in tumor angiogenesis is controversial. We evaluated the angiogenic effect of TNF-alpha on BALB/c mouse colon carcinoma homograft model.
Methods: Ten BALB/c mice were inoculated intraperitoneally with CT-26 mouse colon carcinoma cells. After a week, recombinant mouse TNF-alpha (2 microg/mL) were given four times on every other day to five animals and the same volume of phosphate buffered saline was given at the same interval to five animals as control. Harvested tumor tissues were stained by immunohistochemistry with CD31 and VEGF antibodies. Number of microvessels and VEGF expression were counted by light microscope.
Results: The mean microvessel counts per 200x field of TNF-alpha treated animals were 70.2+/-7.8 and those of nontreated animals were 83.8+/-8.3 (p<0.05). The VEGF score of both groups were 3.
Conclusions: TNF-alpha treated animals showed decreased microvessel counts in tumor tissue but VEGF expression in both groups showed no difference. Therefore, TNF-alpha showed antiangiogenic effects on colon carcinoma homograft model.