Induction of apoptosis by sanguinarine in C6 rat glioblastoma cells is associated with the modulation of the Bcl-2 family and activation of caspases through downregulation of extracellular signal-regulated kinase and Akt.
ABSTRACT Sanguinarine is a benzophenanthridine alkaloid that is derived from the root of Sanguinaria canadensis and other poppy fumaria species, and is known to have antimicrobial, antiinflammatory and antioxidant properties. This study investigated the possible mechanisms through which sanguinarine exerts its antiproliferative action in cultured C6 rat glioblastoma cells. The exposure of C6 cells to sanguinarine resulted in growth inhibition and the induction of apoptosis in a dose-dependent manner, as measured by the MTT assay, fluorescence microscopy, agarose gel electrophoresis and annexin-V-based assay. The sanguinarine treatment induced the proteolytic activation of caspases and ICAD/DFF45, which was associated with the modulation of the Bcl-2 family, concomitant degradation of poly(ADP ribose) polymerase and phospholipase C-gamma1 protein, and DNA fragmentation. z-DEVD-fmk, a caspase-3-specific inhibitor, blocked poly(ADP ribose) polymerase degradation, DNA fragmentation and increased the survival rate of sanguinarine-treated C6 cells. Moreover, the activity of extracellular signal-regulated kinase and Akt was downregulated in sanguinarine-treated cells, and PD98059, a specific extracellular signal-regulated kinase inhibitor, and phosphatidylinositol 3'-kinase/Akt inhibitors, LY294002 and wortmanin, sensitized the cells to sanguinarine-induced apoptosis, indicating that the downregulation of the extracellular signal-regulated kinase and Akt signaling pathway may play a key role in sanguinarine-induced apoptosis in C6 cells.
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ABSTRACT: The interaction of the natural plant alkaloid and anticancer agent sanguinarine with tRNA(phe) has been investigated by spectroscopic and calorimetric techniques. Sanguinarine iminium binds to tRNA(phe) cooperatively; alkanolamine does not bind but in presence of large tRNA(phe) concentration, a conversion from alkanolamine to iminium occurs resulting in concomitant binding of the latter. The binding affinity of the iminium to tRNA(phe) obtained from isothermal titration calorimetry was of the order of 10(5) M(-1), which is close to that evaluated from spectroscopy. The binding was driven largely by negative enthalpy and a smaller but favourable positive entropy change. The binding was dependent on the [Na(+)] concentration, but had a larger non-electrostatic contribution to the Gibbs energy. A small heat capacity value and the enthalpy-entropy compensation in the energetics of the interaction characterized the binding of the iminium form to tRNA(phe). This study confirms that the tRNA(phe) binding moiety is the iminium form of sanguinarine.Journal of biomolecular Structure & Dynamics 06/2012; 30(2):223-34. · 2.98 Impact Factor
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ABSTRACT: We examined the effects of sanguinarine, a benzophenanthridine alkaloid, on reactive oxygen species (ROS) production and the association of these effects with apoptotic cell death in a human colorectal cancer HCT-116 cell line. Sanguinarine generated ROS, which was followed by a decrease in the mitochondrial membrane potential (MMP), the activation of caspase-9 and -3, and the down-regulation of anti-apoptotic proteins, such as Bcl2, XIAP and cIAP-1. Sanguinarine also promoted the activation of caspase-8 and truncation of Bid (tBid). However, the quenching of ROS generation by N-acetyl-L-cysteine, a scavenger of ROS, reversed the sanguinarine-induced apoptosis effects via inhibition of the MMP collapse, tBid expression, and activation of caspases. Sanguinarine also markedly induced the expression of the early growth response gene-1 (Egr-1) during the early period, after which expression level was decreased. In addition, HCT-116 cells transfected with Egr-1 siRNA displayed significant blockage of sanguinarine-induced apoptotic activity in a ROS-dependent manner. These observations clearly indicate that ROS, which are key mediators of Egr-1 activation and MMP collapse, are involved in the early molecular events in the sanguinarine-induced apoptotic pathway acting in HCT-116 cells.Toxicology Letters 05/2013; · 3.15 Impact Factor
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ABSTRACT: To evaluate the in-vivo preclinical antitumor activity of sanguinarine in a rat syngeneic model of colorectal cancer. The effects of sanguinarine on DHD/K12/TRb colorectal adenocarcinoma cells were first evaluated in vitro by means of ³H-thymidine incorporation, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS) assay, and terminal transferase dUTP nick end labeling (TUNEL) microscopy. For the in-vivo studies, DHD/K12/TRb cells (1.5 × 10⁶ cells/0.3 ml of sterile saline/animal) were injected subcutaneously in syngeneic BDIX rats, which were chronically treated with sanguinarine (5 mg/kg/day per os) or control diluent. Tumor growth, body weight, hematologic, and clinical chemistry measurements were monitored in individual animals at defined time intervals. After killing, subcutaneous tumors were explanted from experimental animals for histopathological examination. In vitro, micromolar concentrations of sanguinarine inhibited dose-dependently DHD/K12/TRb cell proliferation and metabolism and induced cell death by apoptosis. In vivo, oral administration of sanguinarine induced a significant inhibition of tumor growth (P<0.01 vs. untreated controls), in the absence of any toxic or side effects. Marked apoptosis and reduced peritumoral vascularization were observed in tumors from sanguinarine-treated rats as compared with the controls. Additional basic studies are needed to fully characterize the mechanism/s underlying the inhibitory effects of sanguinarine on angiogenesis and tumor growth as well as the pharmacological and safety profile of this drug in experimental tumor models. Overall, findings from this study suggest that sanguinarine is a likely candidate for further evaluation in cancer therapy.Anti-cancer drugs 08/2011; 23(1):32-42. · 2.23 Impact Factor