Autophagy and apoptosis are interdependent and inhibition of important autophagic genes such as beclin-1, ATG5, ATG7 and ATG10 leads the cell to apoptotic cell death [10], in contrast the addition BIBW2992 mw of inhibitors that block the fusion of autophagosome with lysosomes, manifested mixed type of morphological features of autophagy and apoptosis (Gonzalez-Polo et al., 2005; [6]).

Caspase-3 has been found to have a role in controlling both apoptosis and autophagy and its inhibition associated with reversal of both autophagic and apoptotic cell death [11]. The specific inhibition of the proapoptotic function of cytochrome c, a key regulator of mitochondria-mediated apoptosis, enhanced autophagy following chemotherapeutic treatment [12]. Apoptosis and autophagy

potential of quinazolinone ring members have been investigated in different cell lines [13] and [14], and in most of the cases the autophagy induced by different quinazoline derivatives are of the protective nature [15]. Our study, for the first time Panobinostat explore the interdependence of autophagy and apoptosis induced by 2,3-Dihydro-2-(quinoline-5-yl)quinazolin-4(1H)-one [DQQ] and negative feedback potential of cytochrome c regulated autophagy in human leukemia MOLT-4 cells. Human acute lymphoblastic leukemia cells MOLT-4 and K-562 were obtained from European Collection of Cell Cultures (ECACC). Cells were grown in RPMI-1640 medium supplemented with 10% heat inactivated fetal bovine serum (FBS), penicillin (100 units/ml), streptomycin (100 μg/ml), L-glutamine (0.3 mg/ml), sodium pyruvate (550 mg/ml), and NaHCO3(2 mg/ml). Cells were grown in a CO2 incubator (Thermocon Electron Corporation, USA) at 37 °C in an atmosphere of 95% air and 5% Inositol monophosphatase 1 CO2 with 98% humidity. Cells treated with DQQ and other inhibitors were dissolved in DMSO while the untreated cells

received the vehicle (DMSO < 0.2%). RPMI-1640, DMEM, EMEM, propidium iodide (PI), 3-(4, 5, -dimethylthiazole-2-yl)-2, 5 diphenyltetrazolium bromide (MTT), 2, 7-dichlorofuoresceine diacetate (DCFH-DA), MG-132, Hoechst-33258, protease inhibitor cocktail, RNase, Rhodamine-123 (Rh-123), streptomycin, fetal bovine serum, phenyl methane sulfonyl fluoride (PMSF), L-glutamine, pyruvic acid, NAC, sMIT and bovine serum albumin were purchased from Sigma-Aldrich (Bangalore, India). Apoalert caspases-8 and -3 fluorescent assay kits, primary antibodies of cytochrome c and Beclin1were purchased from B.D Biosciences (San Jose, CA). Pan specific caspase inhibitor Z-VAD-fmk, AnnexinV-FITC apoptosis detection kit, primary antibodies to Bcl-2, Bax, caspase-3, caspase-8, PARP-1, β-Actin and siRNA transfection reagent were from Santa Cruz Biotechnology (Santa Cruz, CA). Other remaining antibodies were purchased from Cell signalling technology (Danvers, MA).