Rare-earth orthovanadate nanoparticles trigger Ca-dependent eryptosis.

. Rare-earth orthovanadate nanoparticles (ReVO:Eu, Re = Gd, Y or La) are promising agents for photodynamic therapy of cancer due to their modifiable redox properties. However, their toxicity limits their application.. The aim of this research was to elucidate pro-eryptotic effects of GdVO:Euand LaVO:Eunanoparticles with identification of underlying mechanisms of eryptosis induction and to determine their pharmacological potential in eryptosis-related diseases.. Blood samples (= 9) were incubated for 24 h with 0-10-20-40-80 mg lGdVO:Euor LaVO:Eunanoparticles, washed and used to prepare erythrocyte suspensions to analyze the cell membrane scrambling (annexin-V-FITC staining), cell shrinkage (forward scatter signaling), reactive oxygen species (ROS) generation through 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) staining and intracellular Calevels via FLUO4 AM staining by flow cytometry. Internalization of europium-enabled luminescent GdVO:Euand LaVO:Eunanoparticles was assessed by confocal laser scanning microscopy.Both nanoparticles triggered eryptosis at concentrations of 80 mg l. ROS-mediated mechanisms were not involved in rare-earth orthovanadate nanoparticles-induced eryptosis. Elevated cytosolic Caconcentrations were revealed even at subtoxic concentrations of nanoparticles. LaVO:Eunanoparticles increased intracellular calcium levels in a more pronounced way compared with GdVO:Eunanoparticles. Our data disclose that the small-sized (15 nm) GdVO:Eunanoparticles were internalized after a 24 h incubation, while the large-sized (∼30 nm) LaVO:Eunanoparticles were localized preferentially around erythrocytes.Both internalized GdVO:Euand non-internalized LaVO:Eunanoparticles (80 mg l) promote eryptosis of erythrocytes after a 24 h exposurevia Casignaling without involvement of oxidative stress. Eryptosis is a promising model for assessing nanotoxicity.