The cellular hydration state: role in apoptosis and proliferation

Abstract

Small cell volume changes occur within minutes in response to fluctuations of ambient osmolarity but also under the influence of hormones, substrates, second messengers, and oxidative stress. Isoosmotic cell swelling due to retention of inorganic ions and amino acids is obligatory during the cell cycle whereas cell shrinkage as a result of osmolyte release is an early hallmark of apoptosis known as apoptotic volume decrease. Cell volume changes are registered by osmosensing structures which trigger signals involved in the control of metabolism and gene expression. This review considers the hypothesis that cell volume-dependent signals integrate into the overall signal transduction mediating apoptosis and cell cycle progression, respectively. Understanding the role of cell hydration changes in apoptosis and proliferation is of clinical relevance and provides novel therapeutic aspects.