Induction of apoptosis in HepG2 cells by polysaccharide MEP-II from the fermentation broth of Morchella esculenta
ABSTRACT A novel polysaccharide, MEP-II, isolated from the fermentation broth of Morchella esculenta inhibited the proliferation of human hepatoma cell line (HepG2) through an apoptotic pathway. After HepG2 cells were treated with 150-600 μg MEP-II/ml, typical apoptotic characteristics including externalization of phosphatidylserine residues on the cell surface, nuclear fragmentation, chromatin condensation and cytoplasm shrinkage were observed. Furthermore, reactive oxygen species (ROS) burst and the collapse of mitochondrial membrane potential (Δψm) also occurred in HepG2 cells after incubation of 150-600 μg MEP-II/ml. The antioxidant, 1 mM N-acetyl-L: -cysteine inhibited MEP-II-induced apoptosis, suggesting that ROS are the key mediators for MEP-II-induced apoptosis. MEP-II is therefore a potential anti-tumor agent that induces apoptosis of HepG2 cells through ROS generation.
- SourceAvailable from: Andrea C Ruthes[Show abstract] [Hide abstract]
ABSTRACT: The cytotoxic activity of β-D-glucans isolated from Agaricus bisporus and Lactarius rufus fruiting bodies was evaluated on human hepatocellular carcinoma cells (HepG2). NMR and methylation analysis suggest that these β-D-glucans were composed of a linear (1→6)-linked and a branched (1→3), (1→6)-linked backbone, respectively. They both decreased cell viability at concentrations of up to 100μg.mL(-1), as shown by MTT assay. The amount of LDH released and the analysis of cell morphology corroborated these values and also showed that the β-D-glucan of L. rufus was more cytotoxic to HepG2 cells than that of A. bisporus. The treatment of HepG2 cells with L. rufus and A. bisporus β-D-glucans at a dose of 200μg.mL(-1) for 24h promoted an increase of cytochrome c release and a decrease of ATP content, suggesting that these polysaccharides could promote cell death by apoptosis. Both β-D-glucans were tested against murine primary hepatocytes at a dose of 200μg.mL(-1). The results suggest that the L. rufus β-D-glucan was as cytotoxic for hepatocytes as for HepG2 cells, whereas the A. bisporus β-D-glucan, under the same conditions, was cytotoxic only for HepG2 cells, suggesting cell selectivity. These results open new possibilities for use of mushroom β-D-glucans in cancer therapy.International journal of biological macromolecules 03/2013; 58. DOI:10.1016/j.ijbiomac.2013.03.040 · 3.10 Impact Factor
Article: Structural Control of Metabolic Flux[Show abstract] [Hide abstract]
ABSTRACT: Organisms have to continuously adapt to changing environmental conditions or undergo developmental transitions. To meet the accompanying change in metabolic demands, the molecular mechanisms of adaptation involve concerted interactions which ultimately induce a modification of the metabolic state, which is characterized by reaction fluxes and metabolite concentrations. These state transitions are the effect of simultaneously manipulating fluxes through several reactions. While metabolic control analysis has provided a powerful framework for elucidating the principles governing this orchestrated action to understand metabolic control, its applications are restricted by the limited availability of kinetic information. Here, we introduce structural metabolic control as a framework to examine individual reactions' potential to control metabolic functions, such as biomass production, based on structural modeling. The capability to carry out a metabolic function is determined using flux balance analysis (FBA). We examine structural metabolic control on the example of the central carbon metabolism of Escherichia coli by the recently introduced framework of functional centrality (FC). This framework is based on the Shapley value from cooperative game theory and FBA, and we demonstrate its superior ability to assign "share of control" to individual reactions with respect to metabolic functions and environmental conditions. A comparative analysis of various scenarios illustrates the usefulness of FC and its relations to other structural approaches pertaining to metabolic control. We propose a Monte Carlo algorithm to estimate FCs for large networks, based on the enumeration of elementary flux modes. We further give detailed biological interpretation of FCs for production of lactate and ATP under various respiratory conditions.PLoS Computational Biology 12/2013; 9(12):e1003368. DOI:10.1371/journal.pcbi.1003368 · 4.83 Impact Factor
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ABSTRACT: Liver metastasis is a major cause of mortality in colorectal cancer (CRC). The current study was to investigate the ability of ulinastatin (UTI) and curcumin (CUR) to inhibit CRC liver metastases via modulating matrix metalloproteinase-9 (MMP-9) and E-cadherin expression. Human CRC HCT-116 cells were treated with compounds individually and in combination in order to understand the effect on cell migration and invasion. The HCT-116 cell line was established to stably express luciferase and green fluorescent protein (GFP) by lentiviral transduction (HCT-116-Luc-GFP). We identified an anti-metastasis effect of UTI and CUR on a CRC liver metastasis mouse model. Tumor development and therapeutic responses were dynamically tracked by bioluminescence imaging. Expression of MMP-9 and E-cadherin in metastatic tumors was detected by immunohistochemical assay. Results of wound healing and cell invasion assays suggest that treatment with UTI, CUR, and UTI plus CUR, respectively, significantly inhibit HCT-116 cell migration and invasion. Furthermore, results of CRC hepatic metastasis on a nude mouse model showed that treatment with UTI, CUR alone, and a combination notably inhibited hepatic metastases from CRC and prolonged survival of tumor-bearing mice, especially in the UTI plus CUR group. These results suggest that the combination of UTI and CUR together may offer greater inhibition against metastasis of CRC.OncoTargets and Therapy 02/2014; 7:305-14. DOI:10.2147/OTT.S57126 · 2.31 Impact Factor