Chloride Ion Transport Blockade Enhances the Cytocidal Effects of Sterile Water on Bladder Cancer Cells

We investigated whether 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), a Cl¬ channel blocker, enhanced the cytocidal effects of hypotonic shock on bladder cancer cell lines. RT112 cells demonstrated limited hypotonic swelling with reduced cell rupture. After NPPB treatment, RT112 cells ruptured faster than control cells. After 10 min of sterile water exposure, the proportions of viable RT112 cells treated with DMSO, and 50, 100, 200, and 300 µM NPPB were 13.6±3.4%, and 6.3±1.2%, 2.0±1.1%, 0.7±0.7%, and 0%, respectively. These results suggest that intravesical therapy using sterile water with a Cl- channel blocker represents a potential new adjuvant therapy for bladder cancer.