The present investigation aims to verify whether cadmium (Cd<sup>2+</sup>), a metal possibly accumulated in body tissues from air and food, affects cell volume regulation capability in cultured human embryonic kidney (HEK 293 Phoenix) cells. The osmotic phase (OP), which is the expected cell swelling due to aquaporins involvement after hyposmotic challenge, and regulatory volume decrease (RVD), bringing cell volume back to control values through Ca<sup>2+</sup>-dependent ion efflux (K+ and Cl–), have been monitored in HEK 293 cells treated with Cd<sup>2+</sup> (1-10-100 μM) for different time intervals (30 min, 3 h, overnight) and then submitted to 15 % hyposmotic shock. The results show that both 1 and 10 μM Cd<sup>2+</sup> significantly reduced OP, whereas 100 μM impaired Cd<sup>2+</sup> RVD mechanisms. The use of glutathione (GSH, 200 μM) confirmed that Cd<sup>2+</sup> elicited its effect <em>via</em> oxidative damage, being RVD inhibition after Cd<sup>2+</sup> treatment prevented by this antioxidant compound. Our findings show that: i) HEK 293 cells are a suitable model to assay the effect of xenobiotics on cell homeostasis; ii) Cd<sup>2+</sup>, depending on its concentration, affects cell homeostasis at different levels, <em>i.e.</em> water and ion permeability, responsible for, respectively, OP and RVD mechanism, adding thus more information to the knowledge of Cd<sup>2+</sup> toxicology.
S-Adenosylhomocysteine Hydrolase Overexpression in HEK-293 Cells: Effect on Intracellular Adenosine Levels, Cell Viability, and DNA Methylation