We further investigated the role of members of the Bcl-2 family of proteins from mitochondria. Bcl-2 family proteins play both pro-apoptotic and anti-apoptotic role in cancer cells. The normally Bcl-2 level is much higher in the cancer cell. We observed a drastic

reduction in Bcl-2 expression after the treatment of MOLT-4 cells to DQQ that might be linked with the loss of mitochondrial membrane potential. Bcl-2 inhibition by DQQ alter the symmetry selleck kinase inhibitor of mitochondria, which causes the opening of the mitochondrial transformable pore and brings about Bax translocation from cytosol to mitochondria and consequent release of small molecules like cytochrome c from mitochondria to cytosol. DQQ drastically decreased the Bcl-2/Bax ratio in MOLT-4 cells in a concentration dependent manner in 24 h time period (Fig. 3 C). Translocation of these proteins impairs mitochondrial functions and brings the cells to a “point

of no return” to enter apoptosis via caspases activation. Caspase activation selleck products is solely regulated by the mitochondrial release of apoptotic protease activating factor-1 (Apaf-1) and cytochrome c, which is a part of the mitochondrial dependant apoptosis pathway [31]. Translocation of cytochrome c from mitochondria to cytosol is considered as one of the main events of mitochondrial dysfunction and subsequent apoptosis; it is also associated with immediate exposure of phosphatidylserine exposure. In light of earlier experiments that demonstrated induction of MMP loss and exposure of phosphatidylserine by DQQ, we decided to check the cytochrome c translocation and found that it significantly induced cytochrome c release from mitochondria that activate caspase-3 (Fig. 3A, B). The elevated level

of caspase-3 could utilize poly-ADP Ribose polymerase (PARP, 116 kDa), a DNA repair enzyme as its substrate. As a result a cleaved product (85 kDa) of PARP was observed in our study. Subsequently, DQQ treatments also induce caspase-8, which was part of the extrinsic apoptosis pathway. (Fig. 3A, B). So these findings suggest that DQQ caused induction of apoptosis through both intrinsic and extrinsic apoptotic pathways in human leukemia MOLT-4 cells. We have also found DQQ as a potent inducer of autophagy during in MOLT-4 cells. The autophagy induction was confirmed by acridine orange staining, LC3 immunofluorescence and western blot analysis. PI3 K/AKT signaling pathway is one of the important targets in cancer therapy and has been found to be negatively associated with both autophagy and apoptosis [26]. DQQ significantly inhibited the expression of major proteins of this pathway suggesting the role of PI3 K/AKT pathway in autophagy and apoptosis induced by DQQ in MOLT-4 cells. Caspases have been found to have a regulatory role on both apoptosis and autophagy (Zhang et al.