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1.
Int J Radiat Oncol Biol Phys ; 106(4): 867-877, 2020 03 15.
Article in English | MEDLINE | ID: mdl-31786278

ABSTRACT

PURPOSE: The incidence of mesothelioma continues to rise and prognosis remains dismal owing to resistance to conventional therapies and few novel treatment options. Failure to activate apoptotic cell death is a resistance mechanism that may be overcome by inhibition of antiapoptotic Bcl-2 proteins using BH3-mimetic drugs. We investigated the role of antiapoptotic proteins in the radioresistance of mesothelioma, identifying clinically relevant targets for radiosensitization and evaluating the activity of BH3-mimetics alone and in combination with radiation therapy in preclinical models. METHODS, MATERIALS AND RESULTS: Mesothelioma cell lines 211H, H2052, and H226 exposed to BH3-mimetics demonstrated Bcl-xL dependence that correlated with protein expression and was confirmed by genetic knockdown. The Bcl-xL inhibitor A1331852 exhibited cytotoxic (EC50, 0.13-1.42 µmol/L) and radiosensitizing activities (sensitizer enhancement ratios, 1.3-1.8). Cytotoxicity was associated with induction of mitochondrial outer membrane permeabilization and caspase-3/7 activation. Efficacy was maintained in a 3-dimensional model in which combination therapy completely eradicated mesothelioma spheroids. Clinical applicability was confirmed by immunohistochemical analysis of Bcl-2 proteins in patient samples and radiosensitizing activity of A1331852 in primary patient-derived mesothelioma cells. CONCLUSIONS: Mesothelioma cells exhibit addiction to the antiapoptotic protein Bcl-xL, and their intrinsic radioresistance can be overcome by small molecule inhibition of this novel therapeutic target.


Subject(s)
Apoptosis/drug effects , Apoptosis/radiation effects , Mesothelioma/pathology , Peptide Fragments , Peptidomimetics/pharmacology , Proto-Oncogene Proteins , Radiation-Sensitizing Agents/pharmacology , bcl-X Protein/metabolism , Cell Line, Tumor , Cell Survival/drug effects , Cell Survival/radiation effects , Humans
2.
Lung Cancer ; 132: 24-27, 2019 06.
Article in English | MEDLINE | ID: mdl-31097089

ABSTRACT

Radiation remains an important component of mesothelioma treatment in 2018. Its use as a treatment modality continues to evolve as the technology for planning and delivery continues to improve. Use of radiation to improve local control in the involved hemithorax has been a common adjuvant treatment post extrapleural pneumonectomy for many years. Modern treatment options with advanced planning techniques including protons and intensity modulated radiation therapy lead to new potential options for treatment post lung-sparing surgery or in the unresectable setting. Presentations and discussions on the implementation of these strategies for palliation, treatment of oligometastatic recurrence or unresectable disease were the focus of a session dedicated to the role of radiation therapy at the 14th International Conference of the International Mesothelioma Interest Group and are reviewed in this article. Preclinical data to better understand how to integrate radiation and the delivery of novel systemic therapy approached like check point inhibitors are also presented.


Subject(s)
Mesothelioma/radiotherapy , Pleural Neoplasms/radiotherapy , Radiation Oncology/trends , Radiotherapy/methods , Animals , Combined Modality Therapy , Congresses as Topic , Humans , International Cooperation , Public Opinion
3.
Radiother Oncol ; 125(1): 1-12, 2017 10.
Article in English | MEDLINE | ID: mdl-28859932

ABSTRACT

Malignant pleural mesothelioma (MPM) is a devastating disease with limited treatment options and a dismal prognosis. Attempts to employ radical radiotherapy in this disease have been limited by the complex shape of the pleura and the dose restrictions necessitated by the close proximity of radiosensitive structures. Recent shifts towards a 'lung sparing' surgical approach in MPM have further heightened these challenges. The aim of this systematic review is to assess recent advances in radiotherapy planning and delivery, to ascertain how these developments have impacted on the feasibility of delivering photon-based, high-dose radiotherapy with radical intent in MPM. Three electronic databases were searched and a total of 249 articles reviewed. The challenge of generating high quality, practice-defining data for diseases such as MPM was highlighted by the identification of just two randomised studies. Much of the literature consisted of low quality, retrospective data with small cohorts and inconsistent reporting on radiotherapy techniques and dosimetry. Nevertheless, a number of prospective phase II studies were identified to suggest that radical doses of radiotherapy can be delivered safely after a lung sparing procedure in MPM, reporting encouraging survival data and acceptable levels of toxicity.


Subject(s)
Lung Neoplasms/radiotherapy , Mesothelioma/radiotherapy , Pleural Neoplasms/radiotherapy , Humans , Mesothelioma, Malignant , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted , Radiotherapy, Intensity-Modulated
4.
Eur J Immunol ; 36(8): 2085-93, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16810633

ABSTRACT

Chimeric mice generated with bone marrow from RelB-deficient (-/-), RelB-heterozygous (+/-) and wild-type (+/+) mice were used to determine how total or partial absence of the transcription factor RelB in haematopoietic cells affects the immune response generated after lymphocytic choriomeningitis virus (LCMV) infection. In RelB(-/-) chimeras, early virus replication was enhanced and LCMV clearance was impaired. Although plasmacytoid dendritic cell numbers were similar, serum interferon (IFN)-alpha levels in RelB(-/-) and RelB(+/-) chimeras were markedly lower than in RelB(+/+) chimeras during early LCMV infection. Further, both RelB(-/-) and RelB(+/-) chimeras mounted a lower-magnitude LCMV-specific CD8(+) T cell response than their RelB(+/+) counterparts, although the LCMV-specific CD8(+) T cells present were differentiated into functional cytotoxic cells. In LCMV-infected RelB(-/-) mice, induction of cross-priming to an independently injected soluble protein, which depends on the IFN-alpha/beta made during the viral infection, was also impaired. Notably, provision of exogenous IFN-alpha did not restore the ability of RelB(-/-) mice to cross-prime. In summary, these results show that the RelB/NF-kappaB pathway is required for optimal IFN-alpha production after LCMV infection and suggest a crucial role for RelB in IFN-alpha-stimulated cross-priming of CD8(+) T cell responses.


Subject(s)
Cross-Priming/immunology , Interferon-alpha/biosynthesis , Interferon-alpha/immunology , Transcription Factor RelB/metabolism , Animals , Cell Count , Cells, Cultured , Chimera/genetics , Dendritic Cells/cytology , Dendritic Cells/immunology , Dendritic Cells/metabolism , Interferon-alpha/blood , Lymphocytic Choriomeningitis/immunology , Lymphocytic Choriomeningitis/metabolism , Lymphocytic Choriomeningitis/virology , Lymphocytic choriomeningitis virus/physiology , Mice , Mice, Inbred C57BL , Mice, Knockout , Ovalbumin/immunology , Spleen/abnormalities , Spleen/cytology , Spleen/immunology , Spleen/metabolism , Transcription Factor RelB/deficiency , Transcription Factor RelB/genetics , Virus Replication
5.
J Immunol ; 175(10): 6275-85, 2005 Nov 15.
Article in English | MEDLINE | ID: mdl-16272278

ABSTRACT

Human coinfection with the helminth parasite Schistosoma mansoni and hepatitis B and hepatitis C viruses is associated with increased hepatic viral burdens and severe liver pathology. In this study we developed a murine S. mansoni/lymphocytic choriomeningitis virus (LCMV) coinfection model that reproduces the enhanced viral replication and liver pathology observed in human coinfections, and used this model to explore the mechanisms involved. Viral coinfection during the Th2-dominated granulomatous phase of the schistosome infection resulted in induction of a strong LCMV-specific T cell response, with infiltration of high numbers of LCMV-specific IFN-gamma-producing CD8+ cells into the liver. This was associated with suppression of production of the Th2 cytokines dominant during S. mansoni infection and a rapid increase in morbidity, linked to hepatotoxicity. Interestingly, the liver of coinfected mice was extremely susceptible to viral replication. This correlated with a reduced intrahepatic type I IFN response following virus infection. Schistosome egg Ags were found to suppress the type I IFN response induced in murine bone marrow-derived dendritic cells by polyinosinic-polycytidylic acid. These results suggest that suppression of the antiviral type I IFN response by schistosome egg Ags in vivo predisposes the liver to enhanced viral replication with ensuing immunopathological consequences, findings that may be paralleled in human schistosome/hepatotropic virus coinfections.


Subject(s)
Arenaviridae Infections/complications , Arenaviridae Infections/immunology , Hepatitis, Viral, Animal/complications , Hepatitis, Viral, Animal/immunology , Lymphocytic choriomeningitis virus , Schistosomiasis mansoni/complications , Schistosomiasis mansoni/immunology , Animals , Antigens, Helminth , Arenaviridae Infections/pathology , Arenaviridae Infections/virology , Cytokines/biosynthesis , Disease Models, Animal , Hepatitis, Viral, Animal/pathology , Hepatitis, Viral, Animal/virology , Humans , Interferon Type I/biosynthesis , Liver/parasitology , Liver/pathology , Liver/virology , Lymphocytic choriomeningitis virus/pathogenicity , Lymphocytic choriomeningitis virus/physiology , Mice , Mice, Inbred C57BL , Parasite Egg Count , Schistosoma mansoni/immunology , Schistosoma mansoni/isolation & purification , Schistosomiasis mansoni/parasitology , Th2 Cells/immunology , Time Factors , Virus Replication
6.
Eur J Immunol ; 35(2): 524-32, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15657949

ABSTRACT

We previously showed that influenza virus infection of mice induces a depletion of bone marrow B lineage cells due to apoptosis of early B cells mediated by a mechanism involving TNF-alpha/LTalpha. Here we demonstrate that this effect is also observed with acute lymphocytic choriomeningitis virus (LCMV) infection and resulted in a deficiency of both splenic transitional B cells and mature follicular B cells. To determine whether there was an associated impairment of humoral immunity, we infected mice with LCMV and 10 days later at the peak of the B cell depletion, inoculated them with influenza virus. We found that influenza virus-specific antibody titers were dramatically reduced in mice recovering from LCMV infection compared to those in mice infected with influenza virus alone. Further, we showed that there was no reduction of the influenza virus-specific antibody response in LCMV-infected TNF-alpha/LTalpha-deficient mice, suggesting that TNF-alpha/LTalpha-mediated effects on bone marrow and/or peripheral lymphocytes were responsible for the observed impairment in humoral immunity. These results show that the TNF-alpha/LTalpha production induced following infection with diverse viruses has detrimental effects on early B cells in the bone marrow, and may be among the factors that lead to the severely compromised humoral immunity observed to subsequent heterologous infections.


Subject(s)
Bone Marrow/virology , Lymphocytic Choriomeningitis/metabolism , Lymphocytic choriomeningitis virus/metabolism , Spleen/virology , Tumor Necrosis Factor-alpha/metabolism , Virus Replication/physiology , Animals , Antibodies/blood , Antibodies/immunology , Antibody Formation/immunology , B-Lymphocytes/immunology , B-Lymphocytes/physiology , Kinetics , Lung/immunology , Lung/virology , Lymphocytic Choriomeningitis/immunology , Lymphocytic choriomeningitis virus/immunology , Mice , Orthomyxoviridae/immunology , Orthomyxoviridae Infections/immunology , Tumor Necrosis Factor-alpha/genetics
7.
Nat Immunol ; 4(10): 1009-15, 2003 Oct.
Article in English | MEDLINE | ID: mdl-14502286

ABSTRACT

CD8+ T cell responses can be generated against antigens that are not expressed directly within antigen-presenting cells (APCs), through a process known as cross-priming. To initiate cross-priming, APCs must both capture extracellular antigen and receive specific activation signals. We have investigated the nature of APC activation signals associated with virus infection that stimulate cross-priming. We show that infection with lymphocytic choriomeningitis virus induces cross-priming by a mechanism dependent on type I interferon (IFN-alpha/beta). Activation of cross-priming by IFN-alpha/beta was independent of CD4+ T cell help or interaction of CD40 and CD40 ligand, and involved direct stimulation of dendritic cells. These data identify expression of IFN-alpha/beta as a mechanism for the induction of cross-priming during virus infections.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , Dendritic Cells/immunology , Interferon Type I/immunology , Lymphocytic Choriomeningitis/immunology , Lymphocytic choriomeningitis virus/immunology , Animals , Antigen Presentation/immunology , CD40 Antigens/immunology , CD40 Ligand/immunology , CD8-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/virology , Female , Interferon Type I/biosynthesis , Lymphocyte Activation/immunology , Lymphocytic Choriomeningitis/virology , Mice , Mice, Inbred C57BL , Mice, Knockout , Ovalbumin/immunology , Specific Pathogen-Free Organisms
8.
Br J Pharmacol ; 135(2): 407-16, 2002 Jan.
Article in English | MEDLINE | ID: mdl-11815376

ABSTRACT

Non-steroidal anti-inflammatory drugs (NSAIDs) induce apoptosis in gastrointestinal cancer cell lines. Similar actions on normal gastric epithelial cells could contribute to NSAID gastropathy. The present work therefore compared the actions of diclofenac, ibuprofen, indomethacin, and the cyclo-oxygenase-2 selective inhibitor, NS-398, on a primary culture of guinea-pig gastric mucous epithelial cells. Cell number was assessed by staining with crystal violet. Apoptotic activity was determined by condensation and fragmentation of nuclei and by assay of caspase-3-like activity. Necrosis was evaluated from release of cellular enzymes. Ibuprofen (250 microM for 24 h) promoted cell loss, and apoptosis, under both basal conditions and when apoptosis was increased by 25 microM N-Hexanoyl-D-sphingosine (C(6)-ceramide). Diclofenac (250 microM for 24 h) reduced the proportion of apoptotic nuclei from 5.2 to 2.1%, and caused inhibition of caspase-3-like activity, without causing necrosis under basal conditions. No such reduction in apoptotic activity was evident in the presence of 25 microM C(6)-ceramide. The inhibitory effect of diclofenac on basal caspase-3-like activity was also exhibited by the structurally similar mefenamic and flufenamic acids (1 - 250 microM), but not by niflumic acid. Inhibition of superoxide production by the cells increased caspase-3-like activity, but the inhibitory action of diclofenac on caspase activity remained. Diclofenac did not affect superoxide production. Diclofenac inhibited caspase-3-like activity in cell homogenates and also inhibited human recombinant caspase-3. In conclusion, NSAIDs vary in their effect on apoptotic activity in a primary culture of guinea-pig gastric mucous epithelial cells, and the inhibitory effect of diclofenac on basal apoptosis could involve an action on caspase activity.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Apoptosis/drug effects , Diclofenac/pharmacology , Gastric Mucosa/drug effects , Animals , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Apoptosis/physiology , Caspase 3 , Caspase Inhibitors , Caspases/metabolism , Cell Count , Cells, Cultured , Cyclooxygenase Inhibitors/chemistry , Cyclooxygenase Inhibitors/pharmacology , Diclofenac/chemistry , Dose-Response Relationship, Drug , Gastric Mucosa/cytology , Gastric Mucosa/enzymology , Guinea Pigs , Male , Nitrobenzenes/chemistry , Nitrobenzenes/pharmacology , Sulfonamides/chemistry , Sulfonamides/pharmacology
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