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

Abstract

Background:Bladder cancer is a major health concern worldwide. The conventional intravesical Bacillus Calmette–Guérin therapy has certain shortcomings; thereby, demanding novel alternatives. Although sterile water is a probable agent for such novel intravesical therapies, bladder cancer cell lines differ in their sensitivity to hypotonic shock due to sterile water. Therefore, we aimed to investigate whether Cl- channel blockers enhance the cytocidal effect of hypotonic shock on bladder cancer cells resistant to sterile water.Methods:Bladder cancer cell lines of varying grades (RT112, T24, and J82) were exposed to sterile water, and morphological changes were closely observed using microscopy. Sterile water-induced changes in cell membrane integrity and cell viability were analyzed to determine the effects of hypotonic shock. These effects were further analyzed using a Cl- channel blocker.Results:T24 and J82 cells started swelling immediately upon exposure to sterile water and ruptured within 10 min. RT112 cells demonstrated limited hypotonic swelling with few cell ruptures. After treatment with the Cl- channel blocker, RT112 cells ruptured faster as compared to that in cells treated with sterile water. The percentages of viable dimethylsulfoxide and 5-nitro-2-(3-phenylpropylamino) benzoic acid -treated (50, 100, 200, and 300 µM) RT112 cells after 10 min of exposure to sterile water were 13.6 % ± 3.4 %, 6.3 % ± 1.2 %, 2.0 % ± 1.1 %, 0.7 % ± 0.7 %, and 0 %, respectively.Conclusions:Taken together, the Cl- channel blockers enhanced the cytocidal effects of hypotonic shock in bladder cancer cells. Intravesical therapy with sterile water after treatment with a Cl- channel blocker represents a potential new adjuvant therapy after TURBT with high efficacy.