title: Hypertonicity-induced cation channels rescue cells from staurosporine-elicited apoptosis.
abstract: Cell shrinkage is one of the earliest events during apoptosis. Cell shrinkage also occurs upon hypertonic stress, and previous work has shown that hypertonicity-induced cation channels (HICCs) underlie a highly efficient mechanism of recovery from cell shrinkage, called the regulatory volume increase (RVI), in many cell types. Here, the effects of HICC activation on staurosporine-induced apoptotic volume decrease (AVD) and apoptosis were studied in HeLa cells by means of electronic cell sizing and whole-cell patch-clamp recording. It was found that hypertonic stress reduces staurosporine-induced AVD and cell death (associated with caspase-3/7 activation and DNA fragmentation), and that this effect was actually due to activation of the HICC. On the other hand, staurosporine was found to significantly reduce osmotic HICC activation. It is concluded that AVD and RVI reflect two fundamentally distinct functional modes in terms of the activity and role of the HICC, in a shrunken cell. Our results also demonstrate, for the first time, the ability of the HICC to rescue cells from the process of programmed cell death.
authors.affiliation: Department of Cell Physiology, National Institute for Physiological Sciences, Myodaiji-cho, Okazaki 444-8585, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Numata
authors.forename: Kaori
authors.initials: K
authors.lastname: Sato
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Okada
authors.forename: Frank
authors.initials: F
authors.lastname: Wehner
mesh_terms: D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology*; D048429:Cell Size / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D006982:Hypertonic Solutions; D007473:Ion Channels / Q000187:drug effects* / Q000378:metabolism*; D009336:Necrosis; D009997:Osmotic Pressure; D018408:Patch-Clamp Techniques; D019311:Staurosporine / Q000494:pharmacology*
chemical_list: D006982:Hypertonic Solutions; D007473:Ion Channels; D019311:Staurosporine