Fig. 7.

Schematic of Digitoxin and MonoD-induced autophagy. A: To assess the interplay between autophagy and apoptosis, cells were pretreated for 1 h with 2 μM Rapamycin, an autophagy inducer and 10 nM Bafilomycin A1, an autophagy inhibitor. Following this, the cells were treated with Digitoxin and MonoD for 24 h and assessed for apoptosis by staining with 5 μM Hoechst 33342. (*P < 0.05 versus untreated control; #P < 0.05 versus MonoD-treated dataset). B: Quantification of the apoptosis data. C: Digitoxin- and MonoD-driven autophagy is regulated through superoxide, which is mediated via the up-regulation of Beclin-1. MnTBAP scavenges superoxide, which leads to Beclin-1 down-regulation resulting in inhibition of autophagic response. Pro-survival factors Bcl-2 and Akt inhibit autophagy via Beclin-1, which is reversible in the presence of Bcl-2 and Akt inhibitors leading to up-regulation of Beclin-1 expression and increased autophagic response. Prolonged treatment with Digitoxin and MonoD cause sustained autophagy, which eventually sensitizes H460 cells to apoptosis.