67 resultados para Tumor cell lines


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Pristimerin has been shown to be cytotoxic to several cancer cell lines. In the present work, the cytotoxicity of pristimerin was evaluated in human tumor cell lines and in human peripheral blood mononuclear cells (PBMC). This work also examined the effects of pristimerin (0.4; 0.8 and 1.7 mu M) in HL-60 cells, after 6, 12 and 24 h of exposure. Pristimerin reduced the number of viable cells and increased number of non-viable cells in a concentration-dependent manner by tripan blue test showing morphological changes consistent with apoptosis. Nevertheless, pristimerin was not selective to cancer cells, since it inhibited PBMC proliferation with an IC50 of 0.88 PM. DNA synthesis inhibition assessed by 5-bromo-2'-deoxyuridine (BrdU) incorporation in HL-60 cells was 70% and 83% for the concentrations of 0.4 and 0.8 mu M, respectively. Pristimerin (10 and 20 mu M) was not able to inhibit topoisomerase 1. In AO/EB (acridine orange/ethidium bromide) staining, all tested concentrations reduced the number of HL-60 viable cells, with the occurrence of necrosis and apoptosis in a concentration-dependent manner, results in agreement with trypan blue exclusion findings. The analysis of membrane integrity and internucleosomal DNA fragmentation by flow cytometry in the presence of pristimerin indicated that treated cells underwent apoptosis. The present data point to the importance of pristimerin as representative of an emerging class of potential anticancer chemicals, exhibiting an antiproliferative effect by inhibiting DNA synthesis and triggering apoptosis. (c) 2008 Elsevier Ltd. All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The cytotoxic potential of ethanol extracts from Peperomia elongata H. B. & K. (Piperaceae) were evaluated against human cancer cell lines by the MTT method. The samples considered cytotoxic were tested for antimitotic activity with the sea urchin egg development test and for hemolytic activity using mice erythrocytes. The extracts from leaves (hexane), stems (ethanol, hexane, hexane: AcOEt, AcOEt, and MeOH: H2O insoluble), and roots (R4) presented potential cytotoxic action. The stems extracts showed the highest toxicity in all tumor cell lines tested, with an IC50 <= 9.0 mu g/mL for ethanol extract, IC50 <= 11.6 mu g/mL for MeOH:H2O insoluble, IC50 <= 7.3 mu g/mL for hexane extract, IC50 <= 11.4 mu g/mL for hexane: AcOEt, and IC50 <= 16.2 mu g/mL for AcOEt extract. All extracts considered cytotoxic for tumoral cell lines presented antimitotic activity. The samples from roots (R4) and stems (ethanol, MeOH: H2O insoluble, and hexane extract from leaves) were found to possess lytic activity in mice erythrocytes but in higher doses (> 125 mu g/mL). Further studies for the isolation and identification of the active principles of these extracts should be undertaken.

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High-grade prostate cancers express high levels of matrix metalloproteinases (MMPs), major enzymes involved in tumor invasion and metastasis. However, the tumor cell lines commonly employed for prostate cancer research express only small amounts of MMPs when cultivated as monolayer cultures, in common culture media. The present study was conducted to ascertain whether culture conditions that include fibronectin can alter MMP2 and MMP9 expression by the human prostatic epithelial cell lines RWPE-1, LNCaP and PC-3. These cells were individually seeded at 2×104cells/cm2, cultivated until they reached 80% confluence, and then exposed for 4h to fibronectin, after which the conditioned medium was analyzed by gelatin zymography. Untreated cells were given common medium. Only RWPE-1 cells express detectable amounts of MMP9 when cultivated in common medium, whereas the addition of fibronectin induced high expression levels of pro and active forms of MMP2 in all tested cell lines. Our findings demonstrate that normal and tumor prostate cell lines express MMP2 activity when in contact with extracellular matrix components or blood plasma proteins such as fibronectin. Future studies of transcriptomes and proteomes in prostate cancer research using these cell lines should not neglect these important conclusions. © 2012 Elsevier Inc..

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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