Prospective evaluation of improving fluoroquinolone exposure using centralised therapeutic drug monitoring (TDM) in patients with tuberculosis (PERFECT): a study protocol of a prospective multicentre cohort study.

INTRODUCTION: Global multidrug-resistant tuberculosis (MDR-TB) treatment success rates remain suboptimal. Highly active WHO group A drugs moxifloxacin and levofloxacin show intraindividual and interindividual pharmacokinetic variability which can cause low drug exposure. Therefore, therapeutic drug monitoring (TDM) of fluoroquinolones is recommended to personalise the drug dosage, aiming to prevent the development of drug resistance and optimise treatment. However, TDM is considered laborious and expensive, and the clinical benefit in MDR-TB has not been extensively studied. This observational multicentre study aims to determine the feasibility of centralised TDM and to investigate the impact of fluoroquinolone TDM on sputum conversion rates in patients with MDR-TB compared with historical controls. METHODS AND ANALYSIS: Patients aged 18 years or older with sputum smear and culture-positive pulmonary MDR-TB will be eligible for inclusion. Patients receiving TDM using a limited sampling strategy (t=0 and t=5 hours) will be matched to historical controls without TDM in a 1:2 ratio. Sample analysis and dosing advice will be performed in a centralised laboratory. Centralised TDM will be considered feasible if >80% of the dosing recommendations are returned within 7 days after sampling and 100% within 14 days. The number of patients who are sputum smear and culture-negative after 2 months of treatment will be determined in the prospective TDM group and will be compared with the control group without TDM to determine the impact of TDM. ETHICS AND DISSEMINATION: Ethical clearance was obtained by the ethical review committees of the 10 participating hospitals according to local procedures or is pending (online supplementary file 1). Patients will be included after obtaining written informed consent. We aim to publish the study results in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT03409315).

MTH1 favors mesothelioma progression and mediates paracrine rescue of bystander endothelium from oxidative damage.

Oxidative stress and inadequate redox homeostasis is crucial for tumor initiation and progression. MTH1 (NUDT1) enzyme prevents incorporation of oxidized dNTPs by sanitizing the deoxynucleoside triphosphate (dNTP) pool and is therefore vital for the survival of tumor cells. MTH1 inhibition has been found to inhibit the growth of several experimental tumors, but its role in mesothelioma progression remained elusive. Moreover, although MTH1 is nonessential to normal cells, its role in survival of host cells in tumor milieu, especially tumor endothelium, is unclear. We validated a clinically relevant MTH1 inhibitor (Karonudib) in mesothelioma treatment using human xenografts and syngeneic murine models. We show that MTH1 inhibition impedes mesothelioma progression and that inherent tumoral MTH1 levels are associated with a tumor's response. We also identified tumor endothelial cells as selective targets of Karonudib and propose a model of intercellular signaling among tumor cells and bystander tumor endothelium. We finally determined the major biological processes associated with elevated MTH1 gene expression in human mesotheliomas.

Osteopontin drives KRAS-mutant lung adenocarcinoma.

Increased expression of osteopontin (secreted phosphoprotein 1, SPP1) is associated with aggressive human lung adenocarcinoma (LADC), but its function remains unknown. Our aim was to determine the role of SPP1 in smoking-induced LADC. We combined mouse models of tobacco carcinogen-induced LADC, of deficiency of endogenous Spp1 alleles, and of adoptive pulmonary macrophage reconstitution to map the expression of SPP1 and its receptors and determine its impact during carcinogenesis. Co-expression of Spp1 and mutant KrasG12C in benign cells was employed to investigate SPP1/KRAS interactions in oncogenesis. Finally, intratracheal adenovirus encoding Cre recombinase was delivered to LSL.KRASG12D mice lacking endogenous or overexpressing transgenic Spp1 alleles. SPP1 was overexpressed in experimental and human LADC and portended poor survival. In response to two different smoke carcinogens, Spp1-deficient mice developed fewer and smaller LADC with decreased cellular survival and angiogenesis. Both lung epithelial- and macrophage-secreted SPP1 drove tumor-associated inflammation, while epithelial SPP1 promoted early tumorigenesis by fostering the survival of KRAS-mutated cells. Finally, loss and overexpression of Spp1 was, respectively, protective and deleterious for mice harboring KRASG12D-driven LADC. Our data support that SPP1 is functionally involved in early stages of airway epithelial carcinogenesis driven by smoking and mutant KRAS and may present an important therapeutic target.

Versican modulates tumor-associated macrophage properties to stimulate mesothelioma growth.

Versican promotes experimental tumor growth through cell- and non cell-autonomous mechanisms. Its role in mesothelioma progression has not been investigated so far. In this study we investigated the impact of tumor-derived versican in mesothelioma progression and the underlying mechanism of its action. For this purpose, versican-silenced or control ΑΕ17 and ΑΒ1 murine mesothelioma cells were intrapleuraly injected into syngeneic mice, in order to create pleural mesotheliomas and pleural effusions. Intratumoral and pleural immune subsets were assessed using flow cytometry. Mesothelioma cells were co-cultured with syngeneic macrophages to examine versican's impact on their interaction and endothelial cells to assess the effect of versican in endothelial permeability. Versican expression was assessed in human mesotheliomas and mesothelioma-related pleural effusions and benign pleural tissue and effusions. We observed that, versican silencing reduced mesothelioma mass and pleural fluid volume by affecting tumor cell proliferation and apoptosis in vivo, while tumor cell growth remained intact in vitro, and limited pleural vascular permeability. Mice harboring versican-deficient tumors presented fewer tumor/pleural macrophages and neutrophils, and fewer pleural T-regulatory cells, compared to the control animals. Macrophages co-cultured with versican-deficient mesothelioma cells were polarized towards M1 anti-tumor phenotype and demonstrated increased tumor cell phagocytic capacity, compared to macrophages co-cultured with control tumor cells. In co-culture, endothelial monolayer permeability was less effectively stimulated by versican-deficient cells than control cells. Versican was over-expressed in human mesothelioma tissue and mesothelioma-associated effusion. In conclusion, tumor cell-derived versican stimulates mesothelioma progression by shaping a tumor friendly inflammatory milieu, mainly by blunting macrophage anti-tumor activities.

Role of angiopoietins in mesothelioma progression.

BACKGROUND AND OBJECTIVE: Anti-angiogenic treatment has been recently shown to be clinically beneficial for mesothelioma patients. Angiopoietins-1 and -2 are key regulators of tumor angiogenesis. Ang-1 is mainly known to promote angiogenesis and vessel stability, while Ang-2 could serve as an antagonist of Ang-1 causing vessel regression and destabilization or enhance angiogenesis in a context-dependent manner. We hypothesized that Ang-1 would promote and Ang2 would halt experimental mesothelioma by affecting tumor angiogenesis. METHODS: To examine the effects of angiopoietins in mesothelioma angiogenesis and in vivo growth we constructed Ang-1 or Ang-2 overexpressing AE17 and AB1 mesothelioma cells and implanted them in the respective syngeneic animals. We also explored the clinical relevance of our observations using the human tumoral mRNAseq data available in the TCGA database. RESULTS AND CONCLUSIONS: Ang-1 promotes mesothelioma angiogenesis and growth while the effect of Ang-2 is context-dependent. Low Ang-1 levels in human mesotheliomas are associated with the epitheloid subtype. Tumors of high Ang-1, or concurrent high Ang-2 and VEGF expression present high PECAM-1 and CDH5 expression, markers of vascularity and vascular stability, respectively. Our results highlight the importance of angiopoietins in mesothelioma pathophysiology and pave the way for the clinical development of novel anti-angiogenic strategies.

Targeting Tie-2/angiopoietin axis in experimental mesothelioma confers differential responses and raises predictive implications.

Malignant pleural mesothelioma is resistant to currently used treatment. Angiopoieitn-1 directly promotes mesothelioma cell growth in a Tie-2-dependent fashion. Angiopoietin/Tie-2 axis may thus be valid targets for therapeutic interventions against mesothelioma. We hypothesized that a soluble angiopoietin inhibitor (Murine Tek-deltaFc) would halt mesothelioma progression in vivo by enhancing mesothelioma cell proliferation and inhibiting tumor angiogenesis. Our hypothesis was challenged on two syngeneic mesothelioma in vivo models (AB1 cells-Balb/c mice and AE17 cells-C57BL/6 mice. Even though both mesothelioma cell lines express the Angiopoietin-1/-2 and Tie-2, murine Tek-deltaFc hampered AB1 but not AE17 mesothelioma growth in vivo by enhancing tumor cell apoptosis and limiting tumor angiogenesis. Neither angiopoietins (Angs)-1 and -2 nor the inhibitor affected mesothelioma cell growth in vitro. AB1 (responding) tumors were more vascularized and displayed higher endothelial Tie-2 and lower tumor Ang-1 expression than the (non-responding) AE17 tumors. Angiopoietins-1 and -2 are expressed in tumors and pleural cavity of mesothelioma patients demonstrating the clinical relevance of our experimental observations. In conclusion, disrupting Ang-Tie-2 signaling limits mesothelioma angiogenesis and halts tumor progression. Tumor vascularity, endothelial Tie-2 expression and tumor Ang-1 expression may predict mesothelioma response to Tek-deltaFc.

Comparison of effectiveness and safety of imipenem/clavulanate- versus meropenem/clavulanate-containing regimens in the treatment of MDR- and XDR-TB.

No large study to date has ever evaluated the effectiveness, safety and tolerability of imipenem/clavulanate versus meropenem/clavulanate to treat multidrug- and extensively drug-resistant tuberculosis (MDR- and XDR-TB). The aim of this observational study was to compare the therapeutic contribution of imipenem/clavulanate versus meropenem/clavulanate added to background regimens to treat MDR- and XDR-TB cases.84 patients treated with imipenem/clavulanate-containing regimens showed a similar median number of antibiotic resistances (8 versus 8) but more fluoroquinolone resistance (79.0% versus 48.9%, p<0.0001) and higher XDR-TB prevalence (67.9% versus 49.0%, p=0.01) in comparison with 96 patients exposed to meropenem/clavulanate-containing regimens. Patients were treated with imipenem/clavulanate- and meropenem/clavulanate-containing regimens for a median (interquartile range) of 187 (60-428) versus 85 (49-156) days, respectively.Statistically significant differences were observed on sputum smear and culture conversion rates (79.7% versus 94.8%, p=0.02 and 71.9% versus 94.8%, p<0.0001, respectively) and on success rates (59.7% versus 77.5%, p=0.03). Adverse events to imipenem/clavulanate and meropenem/clavulanate were reported in 5.4% and 6.5% of cases only.Our study suggests that meropenem/clavulanate is more effective than imipenem/clavulanate in treating MDR/XDR-TB patients.

Icmt inhibition exerts anti-angiogenic and anti-hyperpermeability activities impeding malignant pleural effusion.

Small GTPases are pivotal regulators of several aspects of tumor progression. Their implication in angiogenesis, vascular permeability and tumor-associated inflammatory responses is relevant to the pathobiology of Malignant Pleural Effusion (MPE). Inhibition of isoprenylcysteine carboxylmethyltransferase (Icmt) abrogates small GTPase activation. We therefore hypothesized that cysmethynil, an Icmt inhibitor would limit pleural fluid accumulation in two models, a lung-adenocarcinoma and a mesothelioma-induced MPE. Cysmethynil significantly reduced MPE volume in both models and tumor burden in the adenocarcinoma model. It inhibited pleural vascular permeability and tumor angiogenesis in vivo and reduced endothelial cell proliferation, migration and tube formation in vitro. Cysmethynil also promoted M1 anti-tumor macrophage homing in the pleural space in vivo, and inhibited tumor-induced polarization of macrophages towards a M2 phenotype in vitro. In addition, the inhibitor promoted adenocarcinoma cell apoptosis in vivo. Inhibition of small GTPase might thus represent a valuable strategy for pharmacotherapy of MPE.

Effectiveness and safety of meropenem/clavulanate-containing regimens in the treatment of MDR- and XDR-TB.

No large study has ever evaluated the efficacy, safety and tolerability of meropenem/clavulanate to treat multidrug- and extensively drug-resistant tuberculosis (MDR- and XDR-TB). The aim of this observational study was to evaluate the therapeutic contribution, effectiveness, safety and tolerability profile of meropenem/clavulanate added to a background regimen when treating MDR- and XDR-TB cases.Patients treated with a meropenem/clavulanate-containing regimen (n=96) showed a greater drug resistance profile than those exposed to a meropenem/clavulanate-sparing regimen (n=168): in the former group XDR-TB was more frequent (49% versus 6.0%, p<0.0001) and the median (interquartile range (IQR)) number of antibiotic resistances was higher (8 (6-9)versus 5 (4-6)). Patients were treated with a meropenem/clavulanate-containing regimen for a median (IQR) of 85 (49-156) days.No statistically significant differences were observed in the overall MDR-TB cohort and in the subgroups with and without the XDR-TB patients; in particular, sputum smear and culture conversion rates were similar in XDR-TB patients exposed to meropenem/clavulanate-containing regimens (88.0% versus 100.0%, p=1.00 and 88.0% versus 100.0%, p=1.00, respectively). Only six cases reported adverse events attributable to meropenem/clavulanate (four of them then restarting treatment).The nondifferent outcomes and bacteriological conversion rate observed in cases who were more severe than controls might imply that meropenem/clavulanate could be active in treating MDR- and XDR-TB cases.

Temsirolimus targets multiple hallmarks of cancer to impede mesothelioma growth in vivo.

BACKGROUND AND OBJECTIVE: The mechanistic target of rapamycin (mTOR) promotes cancer cell proliferation and survival, transduces pro-angiogenic signals and regulates immune cell differentiation and function. We hypothesized that temsirolimus, an mTOR inhibitor, would curtail experimental mesothelioma progression in vivo by limiting tumour cell growth, abrogating tumour angiogenesis and modulating immune/inflammatory tumour milieu. METHODS: We produced flank and pleural syngeneic murine mesotheliomas by delivering AE17 and AB1 murine mesothelioma cells into the right flank or the pleural space of C57BL/6 and BALB/c mice, respectively. Animals were given five times/week intraperitoneal injections of 20 mg/kg temsirolimus or vehicle and were sacrificed on day 26 (flank) or on day 15 (pleural) post-tumour cell propagation. RESULTS: Temsirolimus limited mesothelioma growth in vivo by stimulating tumour cell apoptosis, inhibiting tumour angiogenesis, enhancing tumour lymphocyte abundance and blocking pro-tumour myeloid cell recruitment. Pleural fluid accumulation was significantly mitigated in AE17 but not in AB1 mesotheliomas. In vitro, temsirolimus hindered mesothelioma cell growth, NF-kappaB activation and macrophage migration. CONCLUSIONS: In conclusion, temsirolimus apart from inducing tumour cell apoptosis, targets tumour angiogenesis and influences inflammatory tumour microenvironment to halt experimental mesothelioma growth in vivo.

Interleukin-18 is up-regulated in infectious pleural effusions.

The aim of this study was to investigate the pleural and systemic expression of interleukin-18 (IL-18) in patients with pleural effusions (PEs), and the effects of the cytokine in mouse pleural space. One hundred and sixty patients, 23 with pleural effusions (PEs) due to heart failure, 60 malignant, 25 parapneumonic/empyemas, 15 tuberculous and 37 with exudates of miscellaneous etiologies were included in the study. Pleural fluid (PF) and serum IL-18 content was determined using ELISA. IL-18 was injected intrapleurally in mice and pleural inflammation was assessed using pleural lavage. The highest PF IL-18 levels were observed in parapneumonic PEs and the lowest PF IL-18 levels in patients with exudates of miscellaneous aetiologies and transudates. PF IL-18 levels were significantly higher in patients with empyemas compared to those with uncomplicated (p=0.009) or complicated (p=0.028) parapneumonic effusions, while serum levels did not differ significantly among the three groups. Pleural IL-18 content was higher than that of blood only in patients with empyemas. In patients with pleural exudates of all etiologies and in those with parapneumonic PEs/empyema, PF IL-18 levels were correlated with markers of acute pleural inflammation such as the percentage of PF neutrophils, PF LDH and PF/serum LDH ratio, low PF glucose and PF/serum glucose ratio and low PF pH. In mice, intrapleural IL-18 caused neutrophil-predominant pleural inflammation. In conclusion, IL-18 is linked to the intensity of neutrophilic pleural inflammation in patients with PEs, it is up-regulated in the pleural space of patients with empyema and it stimulates the accumulation of neutrophils in mouse pleura.

Interleukin-17A is involved in bacteria-related acute pleural inflammation.

BACKGROUND AND OBJECTIVE: The role of pro-inflammatory interleukin-17A (IL-17A), in pleural diseases is unknown. We sought to investigate IL-17A expression and its clinical implications in patients with pleural effusion (PE) and IL-17A involvement in the pathobiology of pleural inflammation elicited by bacterial products. METHODS: Pleural and blood IL-17A content was examined in 84 patients with PE of different aetiologies, and the diagnostic value of pleural IL-17A was explored in 92 patients with neutrophil-predominant PE. IL-17A contribution in pleural inflammation was evaluated in mice injected intrapleurally with either IL-17A or bacterial products with or without IL-17A-neutralizing antibodies. RESULTS: IL-17A was upregulated in the pleural space of patients with parapneumonic PE. It was detected in a minority of patients with tuberculous PE and very uncommonly in patients with malignant or other pleural exudates. Pleural fluid (PF) IL-17A levels were correlated with markers of acute pleural inflammation, as well as vascular endothelial growth factor and IL-8 levels. Among patients with neutrophil-predominant PE, PF IL-17A was detected only in those with parapneumonic PE, although the sensitivity of the test was low (<50%). Intrapleural injection of IL-17A elicited a neutrophil-predominant inflammatory response in mice, and IL-17A neutralization partially blocked pleural neutrophilia induced by intrapleural administration of bacterial products. CONCLUSIONS: IL-17A is involved in pleural inflammation related to bacterial infection. Moreover, pleural IL-17A levels may be helpful in uncovering an infectious aetiology among patients with neutrophil-predominant PE.

Static and dynamic mechanics of the murine lung after intratracheal bleomycin.

BACKGROUND: Despite its widespread use in pulmonary fibrosis research, the bleomycin mouse model has not been thoroughly validated from a pulmonary functional standpoint using new technologies. Purpose of this study was to systematically assess the functional alterations induced in murine lungs by fibrogenic agent bleomycin and to compare the forced oscillation technique with quasi-static pressure-volume curves in mice following bleomycin exposure. METHODS: Single intratracheal injections of saline (50 µL) or bleomycin (2 mg/Kg in 50 µL saline) were administered to C57BL/6 (n=40) and Balb/c (n=32) mice. Injury/fibrosis score, tissue volume density (TVD), collagen content, airway resistance (RN), tissue damping (G) and elastance coefficient (H), hysteresivity (η), and area of pressure-volume curve (PV-A) were determined after 7 and 21 days (inflammation and fibrosis stage, respectively). Statistical hypothesis testing was performed using one-way ANOVA with LSD post hoc tests. RESULTS: Both C57BL/6 and Balb/c mice developed weight loss and lung inflammation after bleomycin. However, only C57BL/6 mice displayed cachexia and fibrosis, evidenced by increased fibrosis score, TVD, and collagen. At day 7, PV-A increased significantly and G and H non-significantly in bleomycin-exposed C57BL/6 mice compared to saline controls and further increase in all parameters was documented at day 21. G and H, but not PV-A, correlated well with the presence of fibrosis based on histology, TVD and collagen. In Balb/c mice, no change in collagen content, histology score, TVD, H and G was noted following bleomycin exposure, yet PV-A increased significantly compared to saline controls. CONCLUSIONS: Lung dysfunction in the bleomycin model is more pronounced during the fibrosis stage rather than the inflammation stage. Forced oscillation mechanics are accurate indicators of experimental bleomycin-induced lung fibrosis. Quasi-static PV-curves may be more sensitive than forced oscillations at detecting inflammation and fibrosis.

A sulindac analogue is effective against malignant pleural effusion in mice.

OBJECTIVES: To examine whether a sulindac derivative (C-18) with previously reported anti-angiogenic properties limits malignant pleural effusion (MPE) formation in mice. METHODS: MPE was generated by intrapleural injection of murine adenocarcinoma cells in C57BL/6 mice. Animals were divided into three groups, a control group and two treatment groups receiving intraperitoneally a daily dose of either 1 mg or 2 mg of C-18 for a total of 12 doses. Mice were sacrificed on day 14. MEASUREMENTS AND MAIN RESULTS: Pleural fluid volume and the number of pleural tumor implantations were measured. Tumor angiogenesis, pleural vascular permeability and the host inflammatory response were also assessed. C-18 significantly limited pleural fluid formation and inhibited intrapleural tumor dissemination. The mean±SEM pleural fluid volume was 758±63 µl for the control group, compared to 492±120 µl (p=0.042) and 279±77 µl (p<0.001) for the low dose and high dose group of C-18, respectively. Control group animals had 6.2±1 intrapleural tumors, while C-18 treated animals had 3.1±0.8 (p=0.014) and 3±0.7 (p=0.009) for the low and high dose respectively. In addition C-18 significantly suppressed pleural vascular permeability. No significant difference in tumor angiogenesis and inflammatory response was observed, while there was also no measurable effect in tumor cell apoptosis and proliferation in vitro and in vivo. CONCLUSIONS: C-18 halted experimental MPE formation and intrapleural tumor dissemination, through down-regulation of pleural vascular permeability.

Neutralization of tumor necrosis factor bioactivity ameliorates urethane-induced pulmonary oncogenesis in mice.

Tumor necrosis factor (TNF) has been implicated in inflammation-associated tumor progression. Although multiple reports identified a role for TNF signaling in established cancers, few studies have assessed the impact of TNF blockade on early tumor formation promotion. We aimed at exploring the effects of TNF neutralization in a preclinical mouse model of lung carcinogenesis. For this, Balb/c mice (n = 42) received four weekly intraperitoneal urethane injections (1 g/kg) and twice-weekly intraperitoneal soluble TNF receptor (etanercept; 10 mg/kg) administered during tumor initiation/promotion, tumor progression, or continuously (months 1, 6, and 1-8 after urethane start, respectively). Lung oncogenesis was assessed after 8 months. In separate short-term studies, Balb/c mice (n = 21) received a single control or urethane injection followed by twice-weekly intraperitoneal control or sTNFR:Fc injections. Lung inflammation was assessed after 1 week. We found that sTNFR:Fc treatment during tumor initiation/promotion resulted in a significant reduction of tumor number but not dimensions. However, sTNFR:Fc administered during tumor progression did not impact tumor multiplicity but significantly decreased tumor diameter. Continued sTNFR:Fc administration was effective in halting both respiratory tumor formation and progression in response to urethane. This favorable impact was associated with impaired cellular proliferation and new vessel formation in lung tumors. In addition, TNF neutralization altered the lung inflammatory response to urethane, evidenced by reductions in TNF and macrophage and increases in interferon γ and interleukin 10 content of the air spaces. sTNFR:Fc treatment of RAW264.7 macrophages downregulated TNF and enhanced interferon γ and interleukin 10 expression. In conclusion, TNF neutralization is effective against urethane-induced lung oncogenesis in mice and could present a lung chemoprevention strategy worth testing clinically.

Specific effects of bortezomib against experimental malignant pleural effusion: a preclinical study.

BACKGROUND: We have previously shown that nuclear factor (NF)-kappaB activation of mouse Lewis lung carcinoma (LLC) specifically promotes the induction of malignant pleural effusions (MPE) by these cells. In the present studies we hypothesized that treatment of immunocompetent mice with bortezomib tailored to inhibit cancer cell NF-kappaB activation and not proliferation specifically inhibits MPE formation by LLC cells. RESULTS: Treatment of LLC cells with low concentrations of bortezomib (100 ng/ml) inhibited NF-kappaB activation and NF-kappaB-dependent transcription, but not cellular proliferation. Bortezomib treatment of immunocompetent C57BL/6 mice bearing LLC-induced subcutaneous tumors and MPEs significantly blocked tumor-specific NF-kappaB activation. However, bortezomib treatment did not impair subcutaneous LLC tumor growth, but was effective in limiting LLC-induced MPE. This specific effect was evidenced by significant reductions in effusion accumulation and the associated mortality and was observed with both preventive (beginning before MPE formation) and therapeutic (beginning after MPE establishment) bortezomib treatment. The favorable impact of bortezomib on MPE was associated with suppression of cardinal MPE-associated phenomena, such as inflammation, vascular hyperpermeability, and angiogenesis. In this regard, therapeutic bortezomib treatment had identical favorable results on MPE compared with preventive treatment, indicating that the drug specifically counteracts effusion formation. CONCLUSIONS: These studies indicate that proteasome inhibition tailored to block NF-kappaB activation of lung adenocarcinoma specifically targets the effusion-inducing phenotype of this tumor. Although the drug has limited activity against advanced solid lung cancer, it may prove beneficial for patients with MPE.

Osteopontin is upregulated in malignant and inflammatory pleural effusions.

BACKGROUND AND OBJECTIVE: Osteopontin (OPN) is an important mediator of inflammation and cancer progression. In the present study, we asked whether pleural fluid (PF) and serum OPN concentrations differed between patients with pleural effusions of different aetiologies, and whether assessment of OPN levels was useful for diagnostic purposes. METHODS: One hundred and nine consecutive patients with pleural effusions of different aetiologies were recruited prospectively during daily clinics. OPN levels were measured by ELISA. RESULTS: PF OPN levels were 10-fold higher in exudates than in transudates and were significantly correlated with markers of pleural inflammation and vascular hyper-permeability, such as PF/serum LDH or protein ratios, PF protein and PF vascular endothelial growth factor levels. Patients with malignant pleural effusions had higher PF and lower serum OPN concentrations than those with benign disease. The diagnostic accuracies of PF and PF/serum OPN for malignancy were 71.5% (95% CI: 64-80) and 70.6% (95% CI: 62-80), respectively. CONCLUSIONS: OPN levels were elevated in exudative pleural effusions, as compared with the levels in blood or transudative pleural effusions. While PF and PF/serum OPN were higher in patients with malignancies, the diagnostic accuracy of the tests was not sufficient to permit routine use in clinical practice.

The angiopoietin/Tie2 axis mediates malignant pleural effusion formation.

PURPOSE: Angiopoietins and their receptor, Tie2, participate in angiogenesis, regulation of vascular permeability, and inflammation, all central to the pathogenesis of malignant pleural effusions (MPEs). In the present study, we aimed to examine the role of the angiopoietin/Tie2 axis in MPE pathogenesis. EXPERIMENTAL DESIGN: MPE was induced by intrapleural injection of murine adenocarcinoma cells in C57BL/6 mice. Animals were given twice-weekly intraperitoneal injections of 40 mg/kg MuTekdeltaFc or vehicle. MuTekdeltaFc is a soluble Tie2 (sTie2) receptor that binds murine angiopoietins thereby disrupting their interaction with Tie2 receptors expressed on tissues. Animals were killed on day 14. RESULTS: Angiopoietin/Tie2 axis blockade significantly reduced pleural fluid volume and pleural tumor foci. The mean +/- SEM pleural fluid volumes were 617 +/- 48 microl and 316 +/- 62 microl for the control and treated groups, respectively (P = .001), whereas the mean +/- SEM tumor foci were 7.3 +/- 1.0 and 3.0 +/- 0.52 for the control and treated groups, respectively (P = .001). In addition, tumor-associated cachexia, tumor angiogenesis, pleural vascular permeability, recruitment of inflammatory cells to the pleural cavity, and local elaboration of vascular endothelial growth factor and interleukin 6 were also downregulated, and tumor cell apoptosis was induced in animals treated with the inhibitor. CONCLUSIONS: Our results indicate that the angiopoietin/Tie2 axis is an important component of MPE pathogenesis. Further studies are required to determine whether therapeutic interventions targeting this pathway could be beneficial for patients with MPE.