Induction of apoptosis in Caco-2 cells by exogenously added O2− produced by a nanodevice

The effects of reactive oxygen species on cells have attracted considerable attention in relation to oxidative stress and related disorders. Superoxide (O2−) is the primary reactive oxygen species formed in animals as a byproduct or purposeful product of enzymes. We recently established an O2−-generating nanodevice that produces O2− continuously even in culture medium, by improving an original nanodevice. The new nanodevice, named Device II, efficiently induced cell death in Caco-2 cells in a time- and dose-dependent manner. Catalase largely recovered the cell viability, while superoxide dismutase rather lowered the viability. Flow cytometric and fluorescence microscopic analyses revealed that phosphatidylserine was exposed on the cells and that caspase-3 was activated in the cells after treatment with Device II. These findings indicated that exogenously added O2− caused apoptosis in Caco-2 cells through its derivative H2O2. •A new O2−-generating device based on Nox2 caused cell death in Caco-2 cells.•The cell death was associated with PS exposure and caspase-3 activation.•The cell-death was blocked by catalase, but slightly enhanced by SOD.•Exogenously added O2− induced apoptosis in Caco-2 cells via its derivative H2O2.