curcumin and parthenolide

Identification of novel target pathways in glioblastoma (GBM) remains critical due to poor prognosis, inefficient therapies and recurrence associated with these tumors. In this work, we evaluated the role of nuclear-factor-kappa-B (NFκB) in the growth of GBM cells, and the potential of NFκB inhibitors as antiglioma agents. NFκB pathway was found overstimulated in GBM cell lines and in tumor specimens compared to normal astrocytes and healthy brain tissues, respectively. Treatment of a panel of established GBM cell lines (U138MG, U87, U373 and C6) with pharmacological NFκB inhibitors (BAY117082, parthenolide, MG132, curcumin and arsenic trioxide) and NFκB-p65 siRNA markedly decreased the viability of GBMs as compared to inhibitors of other signaling pathways such as MAPKs (ERK, JNK and p38), PKC, EGFR and PI3K/Akt. In addition, NFκB inhibitors presented a low toxicity to normal astrocytes, indicating selectivity to cancerous cells. In GBMs, mitochondrial dysfunction (membrane depolarization, bcl-xL downregulation and cytochrome c release) and arrest in the G2/M phase were observed at the early steps of NFκB inhibitors treatment. These events preceded sub-G1 detection, apoptotic body formation and caspase-3 activation. Also, NFκB was found overstimulated in cisplatin-resistant C6 cells, and treatment of GBMs with NFκB inhibitors overcame cisplatin resistance besides potentiating the effects of the chemotherapeutics, cisplatin and doxorubicin. These findings support NFκB as a potential target to cell death induction in GBMs, and that the NFκB inhibitors may be considered for in vivo testing on animal models and possibly on GBM therapy.

Topics: Animals; Antineoplastic Agents; Apoptosis; Arsenic Trioxide; Arsenicals; Astrocytes; Brain Neoplasms; Cell Cycle; Cell Death; Cell Line, Tumor; Cisplatin; Curcumin; Doxorubicin; Drug Synergism; Glioblastoma; Humans; Leupeptins; Molecular Targeted Therapy; NF-kappa B; Nitriles; Oxides; Rats; Sesquiterpenes; Signal Transduction; Sulfones

Haemodialysis (HD) patients have many biochemical, immune and inflammatory alterations that can lead to an increased risk for cardiovascular disease. The two major factors affecting these disorders are (a) metabolic, biochemical, immune or inflammatory alterations due to the uremic syndrome per se and (b) alterations due to the therapeutic treatments of uremia, especially HD-induced stress. HD-induced stress includes activation of the pro-inflammatory transcription factor NF-kappaB. In the present study, we have employed lipopolysaccharide (LPS) to activate the peripheral blood mononuclear cells (PBMC), as a model of HD-induced stress. The natural products curcumin, resveratrol and parthenolide are known inhibitors of the activation of NF-kappaB. PBMCs were treated with various concentrations of curcumin, resveratrol and parthenolide and tested for the abilities of these natural products to protect against the LPS-induced expression, secretion of the pro-inflammatory cytokines TNFalpha, IL-1beta and IL-6 and activation of the pro-inflammatory COX-2. We report here that parthenolide is an especially effective natural product that limits the development of a pro-inflammatory state by preventing the activation of all four of these pro-inflammatory signals. The approach of limiting the development of a pro-inflammatory state in HD patients during the dialysis procedure by addition of a natural product that protects against activation of NF-kappaB might be a clinically useful approach to protect leukocytes from HD-induced stress.

Topics: Anti-Inflammatory Agents; Curcumin; Cytokines; Interleukin-1beta; Interleukin-6; Leukocytes, Mononuclear; Lipopolysaccharides; Resveratrol; Sesquiterpenes; Stilbenes; Tumor Necrosis Factor-alpha

The mechanisms of catechol-induced cytotoxicity were studied in cultures of neuroblastoma N2a cells. The minimal cytotoxic concentration after 72 h was 20 micromol x l(-1). The EC50 after 72 h was 38 micromol x l(-1). There was not a correlation between the cytotoxicity and the formation of quinones in the medium. Catechol-induced cytotoxicity was increased significantly when superoxide dismutase (SOD) was added. The addition of catalase did not protect cells, but this enzyme reverted the deleterious effect of SOD. The experimental studies showed a detrimental effect of deferoxamine on catechol-induced cytotoxicity suggesting that cells need iron to maintain its metabolism. NF-kappaB inhibitors increased the cytotoxicity, suggesting that this factor is also important for cell viability. L-cysteine and N-acetyl-L-cysteine protected cells significantly in a dose-dependent manner. The use of monochlorobimane showed that catechol induced reduced glutathione (GSH) depletion after 24 h, prior to cell death. The mode of cell death was studied by flow cytometry after double staining with annexin V and propidium iodide. Catechol induced apoptosis after 72 h. Furthermore, catechol also induced nuclear fragmentation. These data showed that catechol-induced cytotoxicity to N2a cell was not directly a consequence of reactive oxygen species production. Rather, it was due to GSH depletion followed by the induction of apoptosis.

Topics: Animals; Antioxidants; Apoptosis; Ascorbic Acid; Catechols; Cell Line, Tumor; Cell Survival; Curcumin; Cysteine; Cytotoxins; Deferoxamine; Glutathione; Mice; Neuroblastoma; NF-kappa B; Reactive Oxygen Species; Sesquiterpenes; Superoxide Dismutase

During the inflammatory response at least 2 transcription factors, NF-kappaB and AP-1, are involved in the altered profile of gene expression. We used human hepatoma (HepG2) and human umbilical vein endothelial cells (HUVEC) as a model system: NF-kappaB and AP-1 were activated by the proinflammatory cytokine IL-1 in the absence or presence of 21 selected plant extracts and the effect was evaluated by the electrophoretic mobility shift assay (EMSA). In both types of cells activation of NF-kappaB by IL-1 was significantly inhibited by extracts from Scandix australis and Artemisia alba, whereas extracts from Amaranthus sp., Eryngium campestre, Thymus pulegioides and Reichardia picroides elicited cell-type dependent response. The IL-1-induced AP-1 activation was diminished by extracts from Scandix australis, Amaranthus sp. and Artemisia alba more potently in HUVEC, while extracts from Urospermum picroides and Scandix pecten-veneris in HepG2 cells. Inhibitory activities of plant extracts towards cytokine activated NF-kappaB and AP-1 depend to some extent on the order of addition of IL-1 and plant extract to the cell culture, but the mechanism of action of extract components is not clear: although plant polyphenols may participate they are unlikely to be the only mediators, and MAP kinases were found generally not involved in down-regulation of transcription factors activity by plant extracts.

Topics: Acetylcysteine; Anti-Inflammatory Agents; Cells, Cultured; Curcumin; Diet, Mediterranean; Electrophoretic Mobility Shift Assay; Endothelial Cells; Humans; Interleukin-1; Interleukin-6; Mitogen-Activated Protein Kinases; NF-kappa B; Phosphorylation; Plant Extracts; Quercetin; Sesquiterpenes; STAT Transcription Factors; Transcription Factor AP-1

Stromelysin-1 belongs to matrix metalloproteinases responsible for proteolytic degradation of extracellular matrix in many tissues during various diseases, especially those involving inflammation. We studied the induced expression of stromelysin-1 in primary cultures of mouse brain astrocytes stimulated with various cytokines and cellular growth factors. Interleukin-1-beta (IL-1beta), tumor necrosis factor alpha (TNFalpha) and a mixture of IL-1, TNF and epidermal growth factor (EGF) significantly increased the level of stromelysin-1 mRNA in mouse astrocytes while interferon-gamma (IFN-gamma) inhibited this response or was without effect. This accumulation of specific mRNA was preceded by activation of two examined transcription factors: NFkappaB and AP-1. However, experiments with known inhibitors of activation of these transcription factors: pyrrolidine dithiocarbamate (PDTC), parthenolide and curcumin, indicate that NFkappaB and AP-1 cannot be solely responsible for the cytokine induced expression of stromelysin-1 gene in mouse astrocytes.

Topics: Animals; Astrocytes; Brain; Brain Chemistry; Cell Culture Techniques; Curcumin; Cytokines; Drug Synergism; Epidermal Growth Factor; Gene Expression Regulation; Inflammation Mediators; Interferon-gamma; Interleukin-1; Matrix Metalloproteinase 3; Mice; NF-kappa B; Pyrrolidines; RNA, Messenger; Sesquiterpenes; Thiocarbamates; Time Factors; Transcription Factor AP-1; Tumor Necrosis Factor-alpha