cytochrome-c-t and Carcinoma--Ehrlich-Tumor

The blister beetles Epicauta hirticornis and Mylabris cichorii are used as a folk medicine by the Karbi tribe in Karbi Anglong district of Assam, India for the treatment of different human ailments, including cancer cases.. It includes field survey related to zoo-therapeutic aspects of two blister beetles in Karbi community, isolation of bio-active compound and evaluation of its antitumor potential with possible mode of action against murine Ehrlich ascites carcinoma (EAC).. The main bio-active compound of blister beetles was isolated from ethyl acetate extract and the structure was confirmed as cantharidin using NMR, IR, Mass and X-ray diffractometer. The effect of cantharidin on apoptosis, necrosis, autophagy and the apoptosis related signaling pathways were determined using different bioassays, including cell cycle analysis, mitochondrial membrane potential, western blot analysis of cytochrome c, caspases 9, 3/7 assays, and lactate dehydrogenase (LDH) assay.. Cantharidin induced apoptosis, necrosis and autophagy cell death in EAC cells. The decrease in mitochondrial membrane potential was observed, which may help to release cytochrome c from mitochondria to cytosol. Cantharidin treatment caused up-regulation of caspases 9 and -3/7 and a decrease in LDH activity in EAC cells.. The major bioactive compound of these blister beetles is cantharidin which induces severe apoptosis in EAC cells involving mitochondrial intrinsic pathway. Cantharidin-mediated inhibition of LDH activity may lead to short supply of NAD(+) and cut off energy and anabolic supply to cancer cells.

Topics: Animals; Antineoplastic Agents; Cantharidin; Carcinoma, Ehrlich Tumor; Caspases; Cell Cycle; Cell Line, Tumor; Cell Survival; Coleoptera; Cytochromes c; India; Kidney; Liver; Medicine, Traditional; Membrane Potential, Mitochondrial; Mice

Despite of its known cardiotoxicity, doxorubicin is still a highly effective anti-neoplastic agent in the treatment of several cancers. In the present study, the cardioprotective effect of nicorandil was investigated on hemodynamic alterations and mitochondrial dysfunction induced by cumulative administration of doxorubicin in rats. Doxorubicin was injected i.p. over 2 weeks to obtain a cumulative dose of 18 mg/kg. Nicorandil (3 mg/kg/day) was given orally with or without doxorubicin treatment. Heart rate and aortic blood flow were recorded 24 h after receiving the last dose of doxorubicin. Rats were then sacrificed and hearts were rapidly excised for estimation of caspase-3 activity, phosphocreatine and adenine nucleotides contents in addition to cytochrome c, Bcl2, Bax and caspase 3 expression. Moreover, mitochondrial oxidative phosphorylation capacity, creatine kinase activity and oxidative stress markers were measured together with the examination of DNA fragmentation and ultrastructural changes. Nicorandil was effective in alleviating the decrement of heart rate and aortic blood flow and the state of mitochondrial oxidative stress induced by doxorubicin cardiotoxicity. Nicorandil also preserved phosphocreatine and adenine nucleotides contents by restoring mitochondrial oxidative phosphorylation capacity and creatine kinase activity. Moreover, nicorandil provided a significant cardioprotection via inhibition of apoptotic signaling pathway, DNA fragmentation and mitochondrial ultrastructural changes. Interestingly, nicorandil did not interfere with cytotoxic effect of doxorubicin against the growth of solid Ehrlich carcinoma. In conclusion, nicorandil was effective against the development of doxorubicin-induced heart failure in rats as indicated by improvement of hemodynamic perturbations, mitochondrial dysfunction and ultrastructural changes without affecting its antitumor activity.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Carcinoma, Ehrlich Tumor; Cardiotonic Agents; Caspase 3; Cytochromes c; DNA Fragmentation; Doxorubicin; Heart Failure; Heart Rate; Male; Mice; Mitochondria; Myocardium; Nicorandil; Oxidative Phosphorylation; Rats; Rats, Wistar

Catechin is a known hepatoprotective and anticancer agent but has limited bioavailability. Its apoptotic signaling pathway in human hepatocellular carcinoma is vaguely explored. Thus, this study was designed to explore cytotoxicity by MTT assay, induction of apoptosis via DNA fragmentation, nuclear staining, bivariate flow cytometric analysis using annexin V- FITC and propidium iodide, cell cycle analysis and apoptotic markers by RT-PCR and western blotting in HepG2 cells. To increase the bioavailability and selectivity to cancer cells, various liposomes of catechin viz., conventional, charged and PEGylated forms were prepared by film hydration method and evaluated for cytotoxicity in vitro in HepG2 cells and in in vivo in EAC-induced liquid tumor model. Catechin and catechin liposomes inhibited the growth of HepG2 cell lines at concentrations 100-200 μg mL(-1) depending on the length of exposure. It induced apoptosis and inhibited G₂/M phase in cell cycle analysis. Catechin downregulated Bcl-2, initiated the release of cytochrome c into the cytosol and upregulated Bax, caspase-3,-9 and p53 in the HepG2 cells. Catechin and its liposomal formulation, at a dose of 200mg/kg body weight was found to be significantly (p<0.05) effective in inhibiting percentage increase in body weight and enhancing the mean survival time. Deviated hematological parameters, antioxidant parameters (superoxide dismutase, catalase and lipid peroxidation) and LFT in tumor bearing mice were found to be significantly (p<0.05) restored towards normal after treatment with catechin and its liposomes.

Topics: Animals; Antineoplastic Agents; bcl-2-Associated X Protein; Carcinoma, Ehrlich Tumor; Caspase 3; Caspase 9; Catechin; Cell Proliferation; Cell Survival; Chemistry, Pharmaceutical; Cytochromes c; Hep G2 Cells; Humans; Liposomes; Mice; Proto-Oncogene Proteins c-bcl-2; Tumor Suppressor Protein p53

Apoptosis induction is often associated with increased autophagy, indicating interplay between these two important cellular events in cell death and survival. In this study, the programmed cell death and autophagy induced by two nitrostyrene derivative compounds (NTS1 and NTS2) was studied using the tumorigenic Ehrlich ascitic tumor (EAT) cells. EAT cells were highly sensitive to NTS1 and NTS2 cytotoxicity in a dose-dependent manner. NTS1 and NTS2 IC(50) was less than 15.0μM post 12h incubation. Apoptosis was primarily induced by both compounds, as demonstrated by an increase in Annexin-V positive cells, concurrently with cytochrome c release from mitochondria to cytosol and caspase-3 activation. Although cytosolic Ca(2+) mobilization is involved in autophagy as well as apoptosis in response to cellular stress in many cancer cell types, from the two nitrostyrene derivative compounds studied, mainly NTS1 mobilized this ion and disparate autophagy in EAT cells. These results suggest that EAT induced cell death by NTS1 and NTS2 involved a Ca(2+)-dependent and a Ca(2+)-independent pathways, respectively. In accordance with these results, the treatment of EAT cells with 3 methyladenine (3-MA), an autophagy inhibitor; significantly increased the number of apoptotic cells after NTS1 treatment, suggesting that pharmacological modulation of autophagy augments the NTS1 efficacy. Thus, we denote the importance of studies involving autophagy and apoptosis during pre-clinical studies of new drugs with anticancer properties.

Topics: Adenine; Animals; Apoptosis; Apoptosis Regulatory Proteins; Autophagy; Calcium; Carcinoma, Ehrlich Tumor; Caspase 3; Cell Line, Tumor; Cytochromes c; Cytosol; Dose-Response Relationship, Drug; Enzyme Inhibitors; Nitro Compounds; Styrenes

An investigation of the molecular mechanism of the anticancer activity demonstrated by the ruthenium(II)-arene compound [Ru(eta(6)-p-cymene)Cl(2)(pta)] (pta is 1,3,5-triaza-7-phosphaadamantane), termed "RAPTA-C", in Ehrlich ascites carcinoma (EAC) bearing mice is described. RAPTA-C exhibits effective cell growth inhibition by triggering G(2)/M phase arrest and apoptosis in cancer cells. Cell cycle arrest is associated with increased levels of p21 and reduced amounts of cyclin E. RAPTA-C treatment also enhances the levels of p53, and its treatment triggers the mitochondrial apoptotic pathway, as shown by the change in Bax to Bcl-2 ratios, resulting in cytochrome c release and caspase-9 activation. c-Jun NH(2)-terminal kinase (JNK) is a critical mediator in RAPTA-C-induced cell growth inhibition. Activation of JNK by RAPTA-C increases significantly during apoptosis. Overall, these results suggest a critical role for JNK and p53 in RAPTA-C-induced G(2)/M arrest and apoptosis of EAC-bearing mice. Consequently, RAPTA-C treatment results in a significant inhibition in the progression of cancer in an animal model, which emulates the human disease, and does so with remarkably low general toxicity; hence, RAPTA-C has potential for clinical application.

Topics: Animals; Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Carcinoma, Ehrlich Tumor; Caspase 9; Cell Cycle; Cell Cycle Proteins; Cell Nucleus; Cell Proliferation; Cymenes; Cytochromes c; DNA; Gene Expression Regulation, Neoplastic; JNK Mitogen-Activated Protein Kinases; Mice; Mitochondria; Organometallic Compounds; Signal Transduction; Tumor Suppressor Protein p53

In this study we report that, imidazole derivatives can induce apoptosis in Ehrlich ascites tumor (EAT) cells, which is clearly evident from annexin-V staining, flow cytometric analysis of cell cycle phase distribution and DNA fragmentation. Delineating further into molecular mechanisms leading to apoptosis of EAT cells, we observed that imidazole derivatives induce tumor cell death by the up-regulation of proto-oncoprotein Bax, release of cytochrome c from the mitochondria which activates caspase-3 and activated caspase-3 activates CAD (Caspase Activated DNase) causes DNA fragmentation. The status of Bcl-2 remains unaltered in EAT cells, and the under expression of Bcl-2 and up-regulation of Bax resulted in the increase of Bax: Bcl-2 ratio suggesting that Bcl-2 family involved in the control of apoptosis. These results suggest a further possible clinical application of imidazole derivatives as pro-apoptotic agent in association with conventional chemotherapeutic agents.

Topics: Animals; Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Carcinoma, Ehrlich Tumor; Caspase 3; Cytochromes c; Deoxyribonucleases; DNA Fragmentation; Enzyme Activation; Female; Flow Cytometry; Imidazoles; Mice; Protein Transport; Tumor Cells, Cultured; Up-Regulation

Recently the anti-cancer role of black tea has gained immense importance. Nevertheless, the signaling pathways underlying black tea-induced tumor cell death are still unknown. Previously we reported that black tea induces Ehrlich's ascites carcinoma (EAC) cell apoptosis by changing the balance between pro-and anti-apoptotic proteins. It is now well accepted that many cell death pathways converge at the mitochondria to decrease mitochondrial transmembrane potential (MTP) thereby releasing apoptogenic proteins and resulting in the activation of effecter caspases responsible for the biochemical and morphological alterations associated with apoptosis. The role of pro-apoptotic protein, Bax, in initiating mitochondrial death cascade has also been established. Here we demonstrate that in culture black tea extract induces EAC apoptosis in a dose-dependent manner--with IC50 at 100 microg/ml. At this dose, intracellular Bax level increases in EAC followed by its translocation from cytosol to mitochondria resulting in loss in MTP. A search for the downstream pathway further reveals that black tea induces mitochondrial cytochrome c release and activates caspases 9 and 3 by 2 pathways, a) independent of and b) dependent on MTP loss. Interestingly, Black tea-induced death signal might probably be amplified through mitochondrial membrane depolarization via a feedback activation loop from caspase 3. All these findings indicate that black tea initiates mitochondrial death cascade in EAC cells and thereby results in EAC apoptosis.

Topics: Animals; Anticarcinogenic Agents; Apoptosis; Carcinoma, Ehrlich Tumor; Cell Line, Tumor; Cytochromes c; Intracellular Membranes; Membrane Potentials; Mice; Mitochondria; Protein Transport; Tea

We previously demonstrated that evening primrose extract (EPE) induced apoptosis in Ehrlich ascites tumor cells (EATC), and this effect was specific on tumor cells. Furthermore, our results demonstrated that EPE exposure elicited a rapid increase in the activity of superoxide dismutase and intracellular peroxides levels. These changes caused translocation of Bax to mitochondria and a subsequent release of mitochondrial cytochrome c. However, no activation of caspase-3 was observed in EPE-treated EATC. On the other hand, apoptosis-inducing factor (AIF) was translocated from mitochondria to nuclei. The EPE-induced translocation of AIF was suppressed with the addition of catalase, suggesting that the rapid intracellular peroxide levels after addition of EPE triggers off induction of apoptosis, which is AIF-mediated and caspase-independent. In this study, we have shown that EPE elicited a dose-dependent accumulation of cells in the G1 phase and inhibited DNA synthesis. Our results also demonstrated that cell cycle arrest and inhibition of proliferation in EATC by EPE are associated with decreased Rb phosphorylation. Furthermore, inhibitions of Rb phosphorylation and DNA synthesis by EPE were not suppressed with the addition of catalase. The present study suggests that intracellular peroxides, which trigger off induction of apoptosis, are not the trigger of EPE-induced G1 arrest in cell cycle.

Topics: Animals; Apoptosis; Apoptosis Inducing Factor; Blotting, Western; Carcinoma, Ehrlich Tumor; Caspase 3; Caspases; Catalase; Cell Cycle; Cell Division; Cell Line; Cell Line, Tumor; Cell Nucleus; Cell Survival; Cytochromes c; DNA; Dose-Response Relationship, Drug; Flavoproteins; G1 Phase; Hydrogen Peroxide; Membrane Proteins; Mice; Mitochondria; Phosphorylation; Plant Extracts; Primula; Protein Transport; Reactive Oxygen Species; Retinoblastoma Protein; Time Factors