Quercetin Affects Hsp70/IRE1α Mediated Protection from Death Induced by Endoplasmic Reticulum Stress
Low doses of the ER stressors, TN or TG, are not cytotoxic to U937 cells. U937 cells either exposed or not to TN 1 μM or TG 200 nM for 24 h. (a) A cell portion was unfixed, stained with PI and immediately ≥10000 events were analyzed in a cytofluorimeter in order to evaluate the dead cells incorporating PI as percentage of total events. (b and c) A cell portion was fixed and thereafter stained with PI in order to evaluate by cytofluorimetry, among ≥10000 events, those in sub-G1 (b) and in sub-G1, G1, S, and G2M (c) of the cell cycle. The reported values represent the means and error bars, the S.D. of dead cells (PI+), or sub-G1 events of 12 independent experiments. Assessment of cell death showed statistically significant differences between the data obtained in the cultures treated with TN or TG in comparison with the untreated cultures ().