In vitro antitumor activity of bropirimine against urinary bladder tumor cells

Abstract

Background: Bropirimine is an orally-active immunostimulant that has an antitumor effect on superficial transitional cell carcinoma of the bladder. The mechanism of its antitumor effect has not yet been clarified.

Materials and methods: The cytokine-mediated antiproliferative activity of bropirimine was tested against cultured KK-47 and 724 cells using a modified human clonogenic tumor assay. Perpheral blood mononuclear cells (PBMCs) obtained from five healthy volunteers were co-cultured with bropirimine and the levels of various cytokines, including IFN-alpha, gamma, IL-1beta and TNF-alpha in the supernatants, were quantified.

Results: Colony formation by both cell lines was directly inhibited by bropirimine in a dose-dependent manner. In co-cultures of bropirimine and PBMCs, the inhibition of colony formation by both cell lines was not enhanced compared with the effect of bropirimine alone. No significant elevation of cytokines was detected in the presence of PBMCs.

Conclusion: The results obtained suggest that bropirimine is like to have direct antitumor activity rather than a cytokine-mediated antitumor effect.