14 research outputs found

    An investigation into the biochemical, molecular and epigenetic effects of fumonisin B1 in liver (HEPG2) cells.

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    Ph. D. University of KwaZulu-Natal, Durban 2014.Fumonisins are carcinogenic mycotoxins that occur world wide in maize and maizebased products intended for human consumption. Consumption of fumonisincontaminated maize as a staple diet has been associated with oesophageal and liver cancer in South Africa and China. Fumonisin B1 (FB1) inhibits sphingolipid biosynthesis and has been implicated in cancer promoting activity in animals and humans. FB1 disrupts DNA methylation and induces chromatin modifications in human hepatoma (HepG2) cells. In this study FB1 (IC50=200μM) altered liver enzyme expression of DNA methyltransferases and demethylases. DNA methyltransferase activities of DNMT1, 3a and 3b were significantly decreased, whilst both DNA methylase (MBD2) activity and expression was significantly up-regulated resulting in global DNA hypomethylation. In addition the histone demethylases, KDM5B and KDM5C, expression was increased. FACS data confirmed FB1 significantly increased global DNA hypomethylation – a process that causes chromatin instability. Next the effect of FB1 on miRNA expression was evaluated; FB1 significantly down-regulated (11 fold) expression of miR-27b. MiR-27b modulates expression of human cytochrome P450 (CYP1B1) that catalyzes the metabolic activation of many procarcinogens. In order to directly assess the effect of miR-27b on CYP1B1 mRNA levels, liver cells were transfected with the mimic to miR-27b. CYP1B1 mRNA and protein expression was significantly up-regulated by 1.8- fold and 2.6- fold respectively. CYP1B1 is post-transcriptionally regulated by miR-27b suggesting that FB1- induced modulation of miR-27b in hepatic cells may be an additional mode of hepatic neoplastic transformation. Finally, the effect of FB1 on the apoptotic pathway in HepG2 cells was investigated using an mRNA expression array panel of pro- and anti- apoptotic molecules. FB1 significantly increased an AIP family member - BIRC 8/ILP-2 (8-fold) in an apoptosis array. In addition, ILP2 protein expression was increased (2.3-fold) with a corresponding decrease in Smac/DIABLO protein levels (1.7-fold). Further analysis showed an FB1 (0μM, 50μM, 100μM, 200μM) dosedependent increase in BIRC-8/ILP-2 mRNA and protein expression in HepG2 cells. This data suggests that FB1 modulates apoptosis in a complex dose-dependent regulation of pro- and anti-apoptotic molecules – and it is not a matter of simply switching on or off. In conclusion, the data shows that FB1 possess epigenetic properties by inducing global DNA hypomethylation, modulating miRNA expression, and increasing expression of the AIP protein family (BIRC8/ILP-2) that may lead to liver tumourigenesis

    Induction of Caspase-Mediated Apoptosis in HepG2 Liver Carcinoma Cells Using Mutagen–Antioxidant Conjugated Self-Assembled Novel Carbazole Nanoparticles and In Silico Modeling Studies

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    In this study, novel self-assembled carbazole-thiooctanoic acid nanoparticles (CTNs) were synthesized from amino carbazole (a mutagen) and thiooctanoic acid (an antioxidant). The nanoparticles were characterized using hyperspectral techniques. Then, the antiproliferative potential of CTNs was determined in HepG2 liver carcinoma cells. This study employed a solvent-antisolvent interaction method to synthesize a spherical CTN of size less than 50 nm. Moreover, CT was subsequently capped to gold nanoparticles (AuNPs) in the additional comparative studies. The CT derivative was synthesized from carbazole and lipoic acid by the amide bond formation reaction using a coupling agent. Furthermore, it was characterized using infrared (IR), 1H nuclear magnetic resonance, dynamic light scattering (DLS), and transmission electron microscopy techniques. The CT-capped gold nanoparticles (CTAuNPs) were prepared from CT, chloroauric acid, and NaBH4. The CTAuNPs were characterized using ultraviolet-visible, high-resolution TEM, DLS, and Fourier transform IR techniques. The cytotoxicity and apoptosis-inducing ability of both nanoparticles were determined in HepG2 cells. The results demonstrate that CTNs exhibit antiproliferative activity in the cancerous HepG2 cells. Moreover, molecular docking and molecular dynamics studies were conducted to explore the therapeutic potential of CT against human EGFR suppressor protein to gain more insights into the binding mode of the CT, which may show a significant role in anticancer therapy

    Centella asiatica modulates cancer cachexia associated inflammatory cytokines and cell death in leukaemic THP-1 cells and peripheral blood mononuclear cells (PBMC’s)

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    Abstract Background Cancer cachexia is associated with increased pro-inflammatory cytokine levels. Centella asiatica (C. asiatica) possesses antioxidant, anti-inflammatory and anti-tumour potential. We investigated the modulation of antioxidants, cytokines and cell death by C. asiatica ethanolic leaf extract (CLE) in leukaemic THP-1 cells and normal peripheral blood mononuclear cells (PBMC’s). Methods Cytotoxcity of CLE was determined at 24 and 72 h (h). Oxidant scavenging activity of CLE was evaluated using the 2, 2-diphenyl-1 picrylhydrazyl (DPPH) assay. Glutathione (GSH) levels, caspase (−8, −9, −3/7) activities and adenosine triphosphate (ATP) levels (Luminometry) were then assayed. The levels of tumour necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β and IL-10 were also assessed using enzyme-linked immunosorbant assay. Results CLE decreased PBMC viability between 33.25–74.55% (24 h: 0.2–0.8 mg/ml CLE and 72 h: 0.4–0.8 mg/ml CLE) and THP-1 viability by 28.404% (72 h: 0.8 mg/ml CLE) (p < 0.0001). Oxidant scavenging activity was increased by CLE (0.05–0.8 mg/ml) (p < 0.0001). PBMC TNF-α and IL-10 levels were decreased by CLE (0.05–0.8 mg/ml) (p < 0.0001). However, PBMC IL-6 and IL-1β concentrations were increased at 0.05–0.2 mg/ml CLE but decreased at 0.4 mg/ml CLE (p < 0.0001). In THP-1 cells, CLE (0.2–0.8 mg/ml) decreased IL-1β and IL-6 whereas increased IL-10 levels (p < 0.0001). In both cell lines, CLE (0.05–0.2 mg/ml, 24 and 72 h) increased GSH concentrations (p < 0.0001). At 24 h, caspase (−9, −3/7) activities was increased by CLE (0.05–0.8 mg/ml) in PBMC’s whereas decreased by CLE (0.2–0.4 mg/ml) in THP-1 cells (p < 0.0001). At 72 h, CLE (0.05–0.8 mg/ml) decreased caspase (−9, −3/7) activities and ATP levels in both cell lines (p < 0.0001). Conclusion In PBMC’s and THP-1 cells, CLE proved to effectively modulate antioxidant activity, inflammatory cytokines and cell death. In THP-1 cells, CLE decreased pro-inflammatory cytokine levels whereas it increased anti-inflammatory cytokine levels which may alleviate cancer cachexia

    Withania somnifera modulates cancer cachexia associated inflammatory cytokines and cell death in leukaemic THP-1 cells and peripheral blood mononuclear cells (PBMC’s)

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    CITATION: Naidoo, D. B., et al. 2018. Withania somnifera modulates cancer cachexia associated inflammatory cytokines and cell death in leukaemic THP-1 cells and peripheral blood mononuclear cells (PBMC’s). BMC Complementary and Alternative Medicine, 18:126, doi:10.1186/s12906-018-2192-y.The original publication is available at https://bmccomplementalternmed.biomedcentral.comBackground: Cancer and inflammation are associated with cachexia. Withania somnifera (W. somnifera) possesses antioxidant and anti-inflammatory potential. We investigated the potential of an aqueous extract of the root of W. somnifera (WRE) to modulate cytokines, antioxidants and apoptosis in leukaemic THP-1 cells and peripheral blood mononuclear cells (PBMC’s). Methods: Cytotoxcity of WRE was determined at 24 and 72 h (h). Oxidant scavenging activity of WRE was evaluated (2, 2-diphenyl-1 picrylhydrazyl assay). Glutathione (GSH) levels, caspase (− 8, − 9, − 3/7) activities and adenosine triphosphate (ATP) levels (Luminometry) were thereafter assayed. Tumour necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β and IL-10 levels were also assessed using enzyme-linked immunosorbant assay. Results: At 24 h, WRE (0.2–0.4 mg/ml) decreased PBMC viability between 20 and 25%, whereas it increased THP-1 viability between 15 and 23% (p < 0.001). At 72 h, WRE increased PBMC viability by 27–39% (0.05, 0.4 mg/ml WRE) whereas decreased THP-1 viability between 9 and 16% (0.05–0.4 mg/ml WRE) (p < 0.001). Oxidant scavenging activity was increased by WRE (0.05–0.4 mg/ml, p < 0.0001). PBMC TNF-α and IL-10 levels were decreased by 0.2–0.4 mg/ml WRE, whereas IL-1β levels were increased by 0.05–0.4 mg/ml WRE (p < 0.0001). In THP-1 cells, WRE (0.05–0.4 mg/ml) decreased TNF-α, IL-1β and IL-6 levels (p < 0.0001). At 24 h, GSH levels were decreased in PBMC’s, whilst increased in THP-1 cells by 0.2–0.4 mg/ml WRE (p < 0.0001). At 72 h, WRE (0.1–0.4 mg/ml) decreased GSH levels in both cell lines (p < 0.0001). At 24 h, WRE (0.2–0.4 mg/ml) increased PBMC caspase (-8, -3/7) activities whereas WRE (0.05, 0.1, 0.4 mg/ml) increased THP-1 caspase (-9, -3/7) activities (p < 0.0001). At 72 h, PBMC caspase (-8, -9, -3/7) activities were increased at 0.05–0.1 mg/ml WRE (p < 0.0001). In THP-1 cells, caspase (-8, -9, -3/7) activities and ATP levels were increased by 0.1–0.2 mg/ml WRE, whereas decreased by 0.05 and 0.4 mg/ml WRE (72 h, p < 0.0001). Conclusion: In PBMC’s and THP-1 cells,WRE proved to effectively modulate antioxidant activity, inflammatory cytokines and cell death. In THP-1 cells, WRE decreased pro-inflammatory cytokine levels, which may alleviate cancer cachexia and excessive leukaemic cell growth.https://bmccomplementalternmed.biomedcentral.com/articles/10.1186/s12906-018-2192-yPublisher's versio

    Centella asiatica modulates cancer cachexia associated inflammatory cytokines and cell death in leukaemic THP-1 cells and peripheral blood mononuclear cells (PBMC’s)

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    CITATION: Naidoo, D. B. et al. 2017. Centella asiatica modulates cancer cachexia associated inflammatory cytokines and cell death in leukaemic THP-1 cells and peripheral blood mononuclear cells (PBMC’s). BMC Complementary and Alternative Medicine, 17:377, doi:10.1186/s12906-017-1865-2.The original publication is available at https://bmccomplementalternmed.biomedcentral.comBackground: Cancer cachexia is associated with increased pro-inflammatory cytokine levels. Centella asiatica (C. asiatica) possesses antioxidant, anti-inflammatory and anti-tumour potential. We investigated the modulation of antioxidants, cytokines and cell death by C. asiatica ethanolic leaf extract (CLE) in leukaemic THP-1 cells and normal peripheral blood mononuclear cells (PBMC’s). Methods: Cytotoxcity of CLE was determined at 24 and 72 h (h). Oxidant scavenging activity of CLE was evaluated using the 2, 2-diphenyl-1 picrylhydrazyl (DPPH) assay. Glutathione (GSH) levels, caspase (−8, −9, −3/7) activities and adenosine triphosphate (ATP) levels (Luminometry) were then assayed. The levels of tumour necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β and IL-10 were also assessed using enzyme-linked immunosorbant assay. Results: CLE decreased PBMC viability between 33.25–74.55% (24 h: 0.2–0.8 mg/ml CLE and 72 h: 0.4–0.8 mg/ml CLE) and THP-1 viability by 28.404% (72 h: 0.8 mg/ml CLE) (p < 0.0001). Oxidant scavenging activity was increased by CLE (0.05–0.8 mg/ml) (p < 0.0001). PBMC TNF-α and IL-10 levels were decreased by CLE (0.05–0.8 mg/ml) (p < 0.0001). However, PBMC IL-6 and IL-1β concentrations were increased at 0.05–0.2 mg/ml CLE but decreased at 0.4 mg/ml CLE (p < 0.0001). In THP-1 cells, CLE (0.2–0.8 mg/ml) decreased IL-1β and IL-6 whereas increased IL-10 levels (p < 0.0001). In both cell lines, CLE (0.05–0.2 mg/ml, 24 and 72 h) increased GSH concentrations (p < 0.0001). At 24 h, caspase (−9, −3/7) activities was increased by CLE (0.05–0.8 mg/ml) in PBMC’s whereas decreased by CLE (0.2–0.4 mg/ml) in THP-1 cells (p < 0.0001). At 72 h, CLE (0.05–0.8 mg/ml) decreased caspase (−9, −3/7) activities and ATP levels in both cell lines (p < 0.0001). Conclusion: In PBMC’s and THP-1 cells, CLE proved to effectively modulate antioxidant activity, inflammatory cytokines and cell death. In THP-1 cells, CLE decreased pro-inflammatory cytokine levels whereas it increased anti-inflammatory cytokine levels which may alleviate cancer cachexia.https://bmccomplementalternmed.biomedcentral.com/articles/10.1186/s12906-017-1865-2Publisher's versio
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