3C,D), even with the lowest concentration employed (10 μM), detected at 24 hours and maintained at 48 hours. Interestingly, when overall mean green fluorescence was evaluated, EFV 50 μM-treated HeLa LC3-GFP cells exhibited a significant increase, which was particularly evident at 48 hours (Fig. 3E). The activation of autophagy shown

by fluorescence microscopy was further confirmed by confocal see more microscopy with HeLa cells stably expressing LC3-GFP stained with the lysosomal fluorescent marker Lysotracker Red. While control cells showed a disperse LC3-GFP signal, LC3-II-specific punctae were present with EFV 25 and 50 μM (24 hours) and only occasionally in those treated with 10 μM (Fig. 4A). Importantly, EFV induced substantial overlapping of the green (LC3-GFP) and the red signal (Lysotracker Red), thus suggesting the formation of autophagolysomes. mTOR inhibitor Analysis of the two signals, displayed as Icorr

in Fig. 4B, revealed statistically significant colocalization in cells treated with 25 and 50 μM of EFV, whereas the value of 10 μM-treated did not differ from that of vehicle-treated cells. To further study mitochondrial degradation by autophagy, additional confocal microscopy experiments were performed in which HeLa cells stably expressing mtdsRed protein were treated with EFV (24 hours). Lysosomes were stained with Lysotracker Green and colocalization of the two signals was assessed. As expected, little or no overlapping of mitochondrial and lysosomal signals was observed in control cells, whereas EFV led to increased positive colocalization (Fig. 5). To our surprise, the concentration-effect

curve seemed hormetic, as EFV 50 μM-treated cells showed less overlapping (Fig. 5). This result indicated a possible blockage of the autophagic flux by EFV 50 μM. Similarly, static cytometry experiments in EFV-treated HeLa cells (24 hours) revealed a major increase in mean Lysotracker Green fluorescence with 50 μM, whereas no changes were detected with 10 μM or 25 μM (Fig. 6A). To confirm these results, we monitored the autophagic flux by studying LC3 expression in both primary hepatic and Hep3B cells in Miconazole the presence of Bafilomycin A1, a vacuolar-type ATPase inhibitor that impairs lysosomal function by inhibiting its Na+H+ pump. In the presence of this compound, accumulation of LC3-II positive autophagosomes would be evidence of an efficient autophagic flux, whereas the lack of such an increase would point to a defect or delay in this process prior to degradation at the lysosome.23 Our WB experiments showed that cotreatment with 20 nM Bafilomycin A1 led to LC3 accumulation in cells treated with EFV 10 μM and 25 μM (24 hours) in a way similar to that observed in control cells. However, in the presence of EFV 50 μM, exposure to Bafilomycin A1 did not induce such an increase (Figs. 6B, 8C).