Monochloramine suppresses the proliferation of colorectal cancer cell line Caco‐2 by both apoptosis and G2/M cell cycle arrest

The aim of this study was to assess a possible role of monochloramine (NH₂Cl), one of the reactive chlorine species, which induce oxidative stress, on the proliferation of colorectal cancer cell line Caco‐2. At concentrations ranging from 10 to 200 μM, NH₂Cl (14–61% inhibition), but not hypochlorous acid, dose‐dependently inhibited the cell viability of Caco‐2 cells. Experiments utilizing methionine (a scavenger of NH₂Cl), taurine‐chloramine and glutamine‐chloramine revealed that only NH₂Cl affects the cancer cell proliferation among reactive chlorine species, with a relative specificity. Furthermore, flow‐cytometry experiments showed that the anti‐proliferative effect of NH₂Cl is partially attributable to both apoptosis and G2/M cell cycle arrest. These results suggest that NH₂Cl has the potential to suppress colorectal cancer cell proliferation. Copyright © 2013 John Wiley & Sons, Ltd.