Identification and quantification of the active component quercetin 3-O-rutinoside from Barringtonia racemosa, targets mitochondrial apoptotic pathway in acute lymphoblastic leukemia

Barringtonia racemosa has been used as a traditional medicine for the treatment of various diseases. The antitumor property of the seed extract of this plant in mice model promotes us to search for the active component present in the fruit extract. Quercetin 3-O-rutinoside (QOR) has been isolated from the fruits of this plant for the first time and quantified by HPLC method. The compound was identified by IR, mass, and NMR (1D, 2D) spectral data analysis. QOR showed dose- and time-dependent anti-proliferative activity in several leukemic cell lines with negligible effect on normal human peripheral blood mononuclear cell (PBMC). A representative T-lineage acute lymphoblastic leukemia cell line (MOLT-3) showed phosphatidyl serine externalization and DNA fragmentation, indicating QOR-induced programed cell death. We established that QOR-induced apoptosis occurred preferentially on accumulation of cells in the sub-G0 phase and genomic DNA fragmentation through the activation of mitochondria-dependent caspase cascade for the first time in T-lineage ALL cell line

Effect of corchorusin-D, a saikosaponin like compound, on B16F10 melanoma cells (in vitro and in vivo)

Corchorusin-D (COR-D), isolated from Corchorus acutangulus, was reported to induce apoptosis in leukemic cells. However, no studies concerning its activity on melanoma cells have been reported. We have evaluated its in vitro anti-cancer activity on melanoma cells (B16F10, SK-MEL-28, and A375). The results demonstrate that CORD showed maximum inhibition of B16F10 cells in vitro. COR-D induced mitochondrial dysfunction and altered the Bax/Bcl-2 ratio with down regulation of pro-caspases 9 and activation of caspase 3 in B16F10 cells, triggering intrinsic pathway of apoptosis. Moreover, it inhibited the in vivo B16F10 tumor growth and increased the survival rate of mice. Greater number of Annexin V-FITC and propidium iodide (PI)- positive tumor cells signified that COR-D induced apoptosis in vivo also. The reduction in tumor growth is well correlated with decreased microvascular density of the tumor cells in treated mice. In conclusion, this study reveals that COR-D-induced mitochondrial dysfunction is responsible for the induction of apoptotic cell deat

Apoptotic effects of mahanine on human leukemic cells are mediated through crosstalk between Apo-1/Fas signaling and the Bid protein and via mitochondrial pathways

Apo-1 (Fas/CD95), a cell surface receptor, triggers apoptosis after binding to its physiological ligand, Apo-1L (FasL/CD95L). This study reports that mahanine, purified from the leaves of Murraya koenigii, has a dose- and time-dependent anti-proliferative activity in acute lymphoid (MOLT-3) and chronic myeloid (K562) leukemic cell lines and in the primary cells of leukemic and myeloid patients, with minimal effect on normal immune cells including CD34+ cells. Leukemic cells underwent phosphatidylserine externalization and DNA fragmentation, indicating mahanine-induced apoptosis. An increase in reactive oxygen species suggests that the mahanine-induced apoptosis was mediated by oxidative stress. A significant drop in the Bcl2/Bax ratio, the loss of mitochondrial transmembrane potential as well as cytochrome c release from the mitochondria to the cytosol suggested involvement of the mitochondrial pathway of apoptosis. Cytochrome c release was followed by the activation of caspase-9, caspase-3 and caspase-7, and cleavage of PARP in both MOLT-3 and K562 cells. In MOLT-3 cells, formation of the Fas-FasL-FADD-caspase-8 heterotetramer occurred, leading to the cleavage of Bid to its truncated form, which consequently resulted in formation of the mitochondrial transmembrane pore. The incubation of MOLT-3 cells with mahanine in the presence of caspase-8 inhibitor or FasL-neutralizing NOK-2 antibody resulted in the decrease of mahanine-induced cell death. Mahanine was also a potent inhibitor of K562 xenograft growth, which was evident in an athymic nude mice model. In summary, these results provide evidence for involvement of the death receptor-mediated extrinsic pathway of apoptosis in the mahanine-induced anticancer activity in MOLT-3 cells, but not in K562 cells, which are deficient in Fas/FasL