110 resultados para tumour necrosis
Resumo:
Exposure to ionizing radiation can increase the risk of cancer, which is often characterized by genomic instability. In environmental exposures to high-LET radiation (e.g. Ra-222), it is unlikely that many cells will be traversed or that any cell will be traversed by more than one alpha particle, resulting in an in vivo bystander situation, potentially involving inflammation. Here primary human lymphocytes were irradiated with precise numbers of He-3(2+) ions delivered to defined cell population fractions, to as low as a single cell being traversed, resembling in vivo conditions. Also, we assessed the contribution to genomic instability of the pro-inflammatory cytokine tumor necrosis factor alpha (TNFA). Genomic instability was significantly elevated in irradiated groups ( greater than or equal totwofold over controls) and was comparable whether cells were traversed by one or two He-3(2+) ions. Interestingly, substantial heterogeneity in genomic instability between experiments was observed when only one cell was traversed. Genomic instability was significantly reduced (60%) in cultures in which all cells were irradiated in the presence of TNFA antibody, but not when fractions were irradiated under the same conditions, suggesting that TNFA may have a role in the initiation of genomic instability in irradiated cells but not bystander cells. These results have implications for low-dose exposure risks and cancer. (C) 2005 by Radiation Research Society.
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5-Fluorouracil (5-FU) is routinely used in the treatment of gastrointestinal, breast and head and neck cancers. A major limitation to the use of this drug is acquired or inherent resistance.
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The effect of hypobaric hypoxia on the in vivo binding of misonidazole was investigated in normal mice and mice bearing T50/80 or CA NT mammary carcinomas. After the intraperitoneal injection of radiolabelled misonidazole, mice were randomised to breathe either room air or air at 0.5 atmospheres. The distribution of misonidazole in liver, kidney, heart, spleen and tumour tissue, 24 h later, was studied by scintillation counting and by autoradiography. Significantly higher misonidazole binding occurred in the livers (x2.5), kidneys (x2.4), spleens (x2.9) and hearts (x1.8) of hypoxic mice compared to controls. Hypobaric hypoxia was associated with a greater than four-fold increase in misonidazole binding within T50/80 tumours. However, significantly higher binding was not demonstrated within CA NT tumours after exposure of tumour-bearing animals to hypoxic conditions. In autoradiographs of hypoxic liver, labelling was intense in regions near to hepatic veins but sparse in areas surrounding portal tracts. This pattern was striking and consistent. In hypoxic kidney, labelling was most intense over tubular cells, less intense over glomeruli and sparse in the renal medulla. It is likely that the hepatic and renal cortical distributions of misonidazole binding reflect local oxygen gradients.
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Small numbers of brain endothelial cells (BECs) are infected in children with neurologic complications of measles virus (MV) infection. This may provide a mechanism for virus entry into the central nervous system, but the mechanisms are unclear. Both in vitro culture systems and animal models are required to elucidate events in the endothelium. We compared the ability of wild-type (WT), vaccine, and rodent-adapted MV strains to infect, replicate, and induce apoptosis in human and murine brain endothelial cells (HBECs and MBECs, respectively). Mice also were infected intracerebrally. All MV stains productively infected HBECs and induced the MV receptor PVRL4. Efficient WT MV production also occurred in MBECs. Extensive monolayer destruction associated with activated caspase 3 staining was observed in HBECs and MBECs, most markedly with WT MV. Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL), but not Fas ligand, was induced by MV infection. Treatment of MBECs with supernatants from MV-infected MBEC cultures with an anti-TRAIL antibody blocked caspase 3 expression and monolayer destruction. TRAIL was also expressed in the endothelium and other cell types in infected murine brains. This is the first demonstration that infection of low numbers of BECs with WT MV allows efficient virus production, induction of TRAIL, and subsequent widespread apoptosis.
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Recent murine studies have demonstrated that tumour-associated macrophages in the tumour microenvironment are a key source of the pro-tumourigenic cysteine protease, cathepsin S. We now show in a syngeneic colorectal carcinoma murine model that both tumour and tumour-associated cells contribute cathepsin S to promote neovascularisation and tumour growth. Cathepsin S depleted and control colorectal MC38 tumour cell lines were propagated in both wild type C57Bl/6 and cathepsin S null mice to provide stratified depletion of the protease from either the tumour, tumour-associated host cells, or both. Parallel analysis of these conditions showed that deletion of cathepsin S inhibited tumour growth and development, and revealed a clear contribution of both tumour and tumour-associated cell derived cathepsin S. The most significant impact on tumour development was obtained when the protease was depleted from both sources. Further characterisation revealed that the loss of cathepsin S led to impaired tumour vascularisation, which was complemented by a reduction in proliferation and increased apoptosis, consistent with reduced tumour growth. Analysis of cell types showed that in addition to the tumour cells, tumour-associated macrophages and endothelial cells can produce cathepsin S within the microenvironment. Taken together, these findings clearly highlight a manner by which tumour-associated cells can positively contribute to developing tumours and highlight cathepsin S as a therapeutic target in cancer.
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Purpose: The aetiology of primary brain tumours is largely unknown; the role of non-steroidal anti-inflammatory drugs (NSAIDs) or aspirin use and glioma risk has been inconclusive, but few population-based studies with reliable prescribing data have been conducted, and the association with meningioma risk has yet to be assessed. Methods: The UK Clinical Practice Research Datalink was used to assess the association between aspirin and non-aspirin NSAID use and primary brain tumour risk using a nested case-control study design. Conditional logistic regression analysis was performed on 5,052 brain tumour patients aged 16 years and over, diagnosed between 1987 and 2009 and 42,678 controls matched on year of birth, gender and general practice, adjusting for history of allergy and hormone replacement therapy use in the glioma and meningioma models, respectively.
Results: In conditional logistic regression analysis, excluding drug use in the year preceding the index date, there was no association with non-aspirin NSAID use (OR 0.96, 95 % CI 0.81-1.13) or glioma risk comparing the highest category of daily defined dose to non-users; however, non-aspirin NSAID use was positively associated with meningioma risk (OR 1.35, 95 % CI 1.06-1.71). No association was seen with high- or low-dose aspirin use irrespective of histology.
Conclusions: This large nested case-control study finds no association between aspirin or non-aspirin NSAID use and risk of glioma but a slight increased risk with non-aspirin NSAIDs and meningioma. © 2013 Springer Science+Business Media Dordrecht.
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Objective: Vascular lineage differentiation of stem/progenitor cells can contribute to both tissue repair and exacerbation of vascular diseases such as in vein grafts. The role of macrophages in controlling vascular progenitor differentiation is largely unknown and may play an important role in graft development. This study aims to identify the role of macrophages in vascular stem/progenitor cell differentiation and thereafter elucidate the mechanisms that are involved in the macrophage- mediated process.
Approach and Results: We provide in vitro evidence that macrophages can induce endothelial cell (EC) differentiation of the stem/progenitor cells while simultaneously inhibiting their smooth muscle cell differentiation. Mechanistically, both effects were mediated by macrophage-derived tumor necrosis factor-α (TNF-α) via TNF-α receptor 1 and canonical nuclear factor-κB activation. Although the overexpression of p65 enhanced EC (or attenuated smooth muscle cell) differentiation, p65 or TNF-α receptor 1 knockdown using lentiviral short hairpin RNA inhibited EC (or rescued smooth muscle cell) differentiation in response to TNF-α. Furthermore, TNF-α–mediated EC differentiation was driven by direct binding of nuclear factor-κB (p65) to specific VE-cadherin promoter sequences. Subsequent experiments using an ex vivo decellularized vessel scaffold confirmed an increase in the number of ECs and reduction in smooth muscle cell marker expression in the presence of TNF-α. The lack of TNF-α in a knockout mouse model of vein graft decreased endothelialization and significantly increased thrombosis formation.
Conclusions: Our study highlights the role of macrophages in directing vascular stem/progenitor cell lineage commitment through TNF-α–mediated TNF-α receptor 1 and nuclear factor-κB activation that is likely required for endothelial repair in vascular diseases such as vein graft.
Resumo:
Core biopsy is an increasingly used technique in the pre-operative diagnosis of breast carcinoma, as it provides useful prognostic information with respect to tumour type and grade. Neoadjuvant chemotherapy is being used in the treatment of large and locally advanced breast cancers but little is known regarding the correlation between tumour histology on pre-treatment core biopsy and that in residual tumour following primary chemotherapy and surgery. This study aimed to evaluate the accuracy of core biopsy in predicting these features in patients treated with primary chemotherapy. One hundred and thirty-three patients with carcinoma of the breast diagnosed on clinical, radiological and cytological examination underwent core biopsy, followed by primary chemotherapy (with cyclophosphamide, vincristine, doxorubicin and prednisolone) and surgery. The false-negative rate for pre-treatment core biopsy was 14%, with 91% agreement between the grade demonstrated on core biopsy and that in the residual tumour following completion of chemotherapy. Tumour type in the residual post-chemotherapy tumour was predicted by core biopsy in 84%. This study suggests that pre-treatment core biopsy histology accurately predicts residual tumour histology following primary chemotherapy and surgery in patients with breast cancer. (C) 2002 Elsevier Science Ltd. All rights reserved.
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Macrophage migration inhibitory factor (MIF), which inhibits apoptosis and promotes angiogenesis, is expressed in cancers suppressing immune surveillance. Its biological role in human glioblastoma is, however, only poorly understood. We examined in-vivo expression of MIF in 166 gliomas and 23 normal control brains by immunohistochemistry. MIF immunoreactivity was enhanced in neoplastic astrocytes in WHO grade II glioma and increased significantly in higher tumour grades (III-IV). MIF expression was further assessed in 12 glioma cell lines in vitro. Quantitative RT-PCR showed that MIF mRNA expression was elevated up to 800-fold in malignant glioma cells compared with normal brain. This translated into high protein levels as assessed by immunoblotting of total cell lysates and by ELISA-based measurement of secreted MIF. Wild-type p53-retaining glioma cell lines expressed higher levels of MIF, which may be connected with the previously described role of MIF as a negative regulator of wild-type p53 signalling in tumour cells. Stable knockdown of MIF by shRNA in glioma cells significantly increased tumour cell susceptibility towards NK cell-mediated cytotoxicity. Furthermore, supernatant from mock-transfected cells, but not from MIF knockdown cells, induced downregulation of the activating immune receptor NKG2D on NK and CD8+ T cells. We thus propose that human glioma cell-derived MIF contributes to the immune escape of malignant gliomas by counteracting NK and cytotoxic T-cell-mediated tumour immune surveillance. Considering its further cell-intrinsic and extrinsic tumour-promoting effects and the availability of small molecule inhibitors, MIF seems to be a promising candidate for future glioma therapy.