Effect of suramin on human esophageal cancer cells in vitro and in vivo.

BACKGROUND

Suramin disrupts several kinds of growth factor receptors. Since human esophageal squamous cell carcinoma expresses abundant epidermal growth factor receptors (EGFR) and proliferates in an autocrine and paracrine manner, it was expected that suramin inhibits tumor growth by disrupting EGFR.

METHODS

We studied the effect of suramin on the human esophageal squamous cell carcinoma cell line KEsC-II in vitro and in an animal model.

RESULTS

Cell proliferation was stimulated at a low concentration and inhibited at a high concentration of suramin in vitro. Since autophosphorylation of EGFR was stronger at the low concentration and weaker at the high concentration of suramin compared with the control, the effect of suramin was thought to be via phosphorylation of receptors. In the animal model tumor growth was significantly stimulated in the suramin-treated group compared with the control group, and the BrdU labeling index was also higher in the suramin-treated group.

CONCLUSIONS

As it was impossible to increase the dose of suramin intravenously because of side effects, administration of suramin by another method, such as subcutaneous injection around the tumor, may increase the concentration of suramin in the tumor tissue and promote the anti-tumor effect of suramin.