Untutored training pathway to achieve competence in esophagogastric endoscopic submucosal dissection in a Western center.

BACKGROUND AND AIMS: Endoscopic submucosal dissection (ESD) has a long learning curve. The aim of this study was to assess the efficacy of an ESD unsupervised training model for experienced endoscopists. METHODS: Stepwise training included a visit to a high-volume center, unsupervised training on an ex vivo porcine model, and in vivo human upper GI cases with anatomic progression. Performance measures included en bloc resection, R0 resection, adverse event rates, and operating time. RESULTS: After observation of 30 esophagogastric ESDs and 15 untutored ex vivo ESDs, 5 human cases of distal gastric ESDs were performed, followed by 55 unselected esophagogastric cases. En bloc and R0 resection rates were 93.0% and 80.7%, respectively. Operating time was 14.0 min/cm2 in the stomach and 25.1 min/cm2 in the esophagus, with evidence of a learning curve for esophageal ESDs (first block 30.26 min/cm2 vs second block 14.81 min/cm2, P = .01). CONCLUSIONS: Untutored training for esophagogastric ESD is feasible and allows endoscopists, experienced in therapeutic endoscopy, to achieve the required standards toward competency.

MTH1 Inhibition Alleviates Immune Suppression and Enhances the Efficacy of Anti-PD-L1 Immunotherapy in Experimental Mesothelioma.

BACKGROUND: MTH1 protects tumor cells and their supporting endothelium from lethal DNA damage triggered by oxidative stress in the tumor microenvironment, thus promoting tumor growth. The impact of MTH1 on the tumor-related immune compartment remains unknown. We hypothesized that MTH1 regulates immune fitness and therefore enhances the activity of currently used immunotherapeutic regimens. METHODS: Our hypotheses were validated in two syngeneic murine mesothelioma models using the clinically relevant MTH1 inhibitor, karonudib. We also examined the effect of combined MTH1 and PD-L1 blockade in mesothelioma progression, focusing on the main immune players. RESULTS: Karonudib administration enhances M1 macrophage polarization, stimulates CD8 expansion and promotes the activation of DC and T cells. Combined administration of PD-L1 and MTH1 inhibitors impairs mesothelioma tumor growth and mesothelioma-associated pleural effusion accumulation more effectively compared to each monotherapy. CONCLUSIONS: Combined MTH1 and PD-L1 inhibition holds promise for the successful clinical management of mesothelioma.

The effect of procedural time on dysplasia detection rate during endoscopic surveillance of Barrett's esophagus.

BACKGROUND : Endoscopic surveillance of Barrett's esophagus (BE) with Seattle protocol biopsies is time-consuming and inadequately performed in routine practice. There is no recommended procedural time for BE surveillance. We investigated the duration of surveillance procedures with adequate tissue sampling and effect on dysplasia detection rate (DDR). METHODS : We performed post hoc analysis from the standard arm of a crossover randomized controlled trial recruiting patients with BE (≥C2 and/or ≥M3) and no clearly visible dysplastic lesions. After inspection with white-light imaging, targeted biopsies of subtle lesions and Seattle protocol biopsies were performed. Procedure duration and biopsy number were stratified by BE length. The effect of endoscopy-related variables on DDR was assessed by multivariable logistic regression. RESULTS : Of 142 patients recruited, 15 (10.6 %) had high grade dysplasia/intramucosal cancer and 15 (10.6 %) had low grade dysplasia. The median procedural time was 16.5 minutes (interquartile range 14.0-19.0). Endoscopy duration increased by 0.9 minutes for each additional 1 cm of BE length. Seattle protocol biopsies had higher sensitivity for dysplasia than targeted biopsies (86.7 % vs. 60.0 %; P = 0.045). Longer procedural time was associated with increased likelihood of dysplasia detection on quadrantic biopsies (odds ratio [OR] 1.10, 95 %CI 1.00-1.20, P = 0.04), and for patients with BE > 6 cm also on targeted biopsies (OR 1.21, 95 %CI 1.04-1.40; P = 0.01). CONCLUSIONS : In BE patients with no clearly visible dysplastic lesions, longer procedural time was associated with increased likelihood of dysplasia detection. Adequate time slots are required to perform good-quality surveillance and maximize dysplasia detection.

CSF1/CSF1R signaling mediates malignant pleural effusion formation.

Malignant pleural effusion (MPE) is an incurable common manifestation of many malignancies. Its formation is orchestrated by complex interactions among tumor cells, inflammatory cells, and the vasculature. Tumor-associated macrophages present the dominant inflammatory population of MPE, and M2 macrophage numbers account for dismal prognosis. M2 polarization is known to be triggered by CSF1/CSF1 receptor (CSF1R) signaling. We hypothesized that CSF1R+ M2 macrophages favor MPE formation and could be therapeutically targeted to limit MPE. We generated mice with CSF1R-deficient macrophages and induced lung and colon adenocarcinoma-associated MPE. We also examined the therapeutic potential of a clinically relevant CSF1R inhibitor (BLZ945) in lung and colon adenocarcinoma-induced experimental MPE. We showed that CSF1R+ macrophages promoted pleural fluid accumulation by enhancing vascular permeability, destabilizing tumor vessels, and favoring immune suppression. We also showed that CSF1R inhibition limited MPE in vivo by reducing vascular permeability and neoangiogenesis and impeding tumor progression. This was because apart from macrophages, CSF1R signals in cancer-associated fibroblasts leading to macrophage inflammatory protein 2 secretion triggered the manifestation of suppressive and angiogenic properties in macrophages upon CXCR2 paracrine activation. Pharmacological targeting of the CSF1/CSF1R axis can therefore be a vital strategy for limiting MPE.

Image-Enhanced Endoscopy and Molecular Biomarkers Vs Seattle Protocol to Diagnose Dysplasia in Barrett's Esophagus.

BACKGROUND & AIMS: Dysplasia in Barrett's esophagus often is invisible on high-resolution white-light endoscopy (HRWLE). We compared the diagnostic accuracy for inconspicuous dysplasia of the combination of autofluorescence imaging (AFI)-guided probe-based confocal laser endomicroscopy (pCLE) and molecular biomarkers vs HRWLE with Seattle protocol biopsies. METHODS: Barrett's esophagus patients with no dysplastic lesions were block-randomized to standard endoscopy (HRWLE with the Seattle protocol) or AFI-guided pCLE with targeted biopsies for molecular biomarkers (p53 and cyclin A by immunohistochemistry; aneuploidy by image cytometry), with crossover to the other arm after 6 to 12 weeks. The primary end point was the histologic diagnosis from all study biopsies (trial histology). A sensitivity analysis was performed for overall histology, which included diagnoses within 12 months from the first study endoscopy. Endoscopists were blinded to the referral endoscopy and histology results. The primary outcome was diagnostic accuracy for dysplasia by real-time pCLE vs HRWLE biopsies. RESULTS: Of 154 patients recruited, 134 completed both arms. In the primary outcome analysis (trial histology analysis), AFI-guided pCLE had similar sensitivity for dysplasia compared with standard endoscopy (74.3%; 95% CI, 56.7-87.5 vs 80.0%; 95% CI, 63.1-91.6; P = .48). Multivariate logistic regression showed pCLE optical dysplasia, aberrant p53, and aneuploidy had the strongest correlation with dysplasia (secondary outcome). This 3-biomarker panel had higher sensitivity for any grade of dysplasia than the Seattle protocol (81.5% vs 51.9%; P < .001) in the overall histology analysis, but not in the trial histology analysis (91.4% vs 80.0%; P = .16), with an area under the receiver operating curve of 0.83. CONCLUSIONS: Seattle protocol biopsies miss dysplasia in approximately half of patients with inconspicuous neoplasia. AFI-guided pCLE has similar accuracy to the current gold standard. The addition of molecular biomarkers could improve diagnostic accuracy.

Convalescent plasma therapy in an immunocompromised patient with multiple COVID-19 flares: a case report.

Convalescent plasma (CP) transfusion has been utilized as a salvage therapy in immunocompromised patients with severe COVID-19 pneumonia. We describe the case of a 45-year-old immunocompromised patient, who received CP, in order to control multiple COVID-19 flares and prolonged SARS-CoV-2 viraemia lasting for 2 months after the initial diagnosis.

CSF1/CSF1R Axis Blockade Limits Mesothelioma and Enhances Efficiency of Anti-PDL1 Immunotherapy.

Colony-Stimulating Factor 1 (CSF1)/Colony-Stimulating Factor Receptor 1 (CSF1R) signaling orchestrates tumor-associated macrophage (TAM) recruitment and polarization towards a pro-tumor M2 phenotype, the dominant phenotype of TAMs infiltrating mesothelioma tumors. We hypothesized that CSF1/CSF1R inhibition would halt mesothelioma growth by targeting immunosuppressive M2 macrophages and unleashing efficient T cell responses. We also hypothesized that CSF1/CSF1R blockade would enhance the efficacy of a PDL1 inhibitor which directly activates CD8+ cells. We tested a clinically relevant CSF1R inhibitor (BLZ945) in mesothelioma treatment using syngeneic murine models. We evaluated the role of CSF1/CSF1R axis blockade in tumor-infiltrating immune subsets. We examined the effect of combined anti-CSF1R and anti-PDL1 treatment in mesothelioma progression. CSF1R inhibition impedes mesothelioma progression, abrogates infiltration of TAMs, facilitates an M1 anti-tumor phenotype and activates tumor dendritic and CD8+ T cells. CSF1R inhibition triggers a compensatory PD-1/PDL1 upregulation in tumor and immune cells. Combined CSF1R inhibitor with an anti-PDL1 agent was more effective in retarding mesothelioma growth compared to each monotherapy. In experimental mesotheliomas, CSF1R inhibition abrogates tumor progression by limiting suppressive myeloid populations and enhancing CD8+ cell activation and acts synergistically with anti-PDL1.

A 27-Year-Old Man With Intermittent Chest Pain During the Last 4 Years.

CASE PRESENTATION: A 27-year-old man from Eritrea presented to the ED complaining about a progressively worse blunt chest pain in the anterior right hemithorax. Chest pain started 4 years ago and was intermittent. During the last 6 months, symptoms got worse, and the patient experienced shortness of breath in mild exercise. For this purpose, he visited another institution, where a chest radiograph was performed (Fig 1). He was advised to visit a pulmonologist for further evaluation, with the diagnosis of a loculated pleural effusion in the right upper hemithorax.

Thiopurine monotherapy is effective in ulcerative colitis but significantly less so in Crohn's disease: long-term outcomes for 11 928 patients in the UK inflammatory bowel disease bioresource.

OBJECTIVE: Thiopurines are widely used as maintenance therapy in inflammatory bowel disease (IBD) but the evidence base for their use is sparse and their role increasingly questioned. Using the largest series reported to date, we assessed the long-term effectiveness of thiopurines in ulcerative colitis (UC) and Crohn's disease (CD), including their impact on need for surgery. DESIGN: Outcomes were assessed in 11 928 patients (4968 UC, 6960 CD) in the UK IBD BioResource initiated on thiopurine monotherapy with the intention of maintaining medically induced remission. Effectiveness was assessed retrospectively using patient-level data and a definition that required avoidance of escalation to biological therapy or surgery while on thiopurines. Analyses included overall effectiveness, time-to-event analysis for treatment escalation and comparison of surgery rates in patients tolerant or intolerant of thiopurines. RESULTS: Using 68 132 patient-years of exposure, thiopurine monotherapy appeared effective for the duration of treatment in 2617/4968 (52.7%) patients with UC compared with 2378/6960 (34.2%) patients with CD (p<0.0001). This difference was corroborated in a multivariable analysis: after adjusting for variables including treatment era, thiopurine monotherapy was less effective in CD than UC (OR 0.47, 95% CI 0.43 to 0.51, p<0.0001). Thiopurine intolerance was associated with increased risk of surgery in UC (HR 2.44, p<0.0001); with a more modest impact on need for surgery in CD (HR=1.23, p=0.0015). CONCLUSION: Thiopurine monotherapy is an effective long-term treatment for UC but significantly less effective in CD.

Single-bite versus double-bite technique for mapping biopsies during endoscopic surveillance for hereditary diffuse gastric cancer: a single-center, randomized trial.

BACKGROUND : Endoscopic surveillance is recommended in patients with hereditary diffuse gastric cancer (HDGC) who refuse or want to delay surgery. Because early signet-ring cell carcinoma (SRCC) can be inconspicuous, the current surveillance endoscopy protocol entails 30 random biopsies, which are time-consuming. This study aimed to compare single-bite and double-bite techniques in HDGC surveillance. METHODS : Between October 2017 and December 2018, consecutive patients referred for HDGC surveillance were prospectively randomized to the single- or double-bite arm. The primary outcome was the diagnostic yield for SRCC foci. Secondary outcomes were: procedural time for random biopsies; comfort score; biopsy size; and quality of specimens, the latter assessed by the presence of muscularis mucosa, crush artifact, and proportion usable for diagnostic assessment. RESULTS : 25 patients were randomized to the single-bite arm and 23 to the double-bite arm. SRCC foci were detected in three and four patients in the single- and double-bite arms, respectively (P = 0.70). The procedural time for the double-bite arm (12 minutes, interquartile range [IQR] 4) was significantly shorter than for the single-bite arm (15 minute, IQR 6; P = 0.01), but comfort scores were similar. The size of the biopsies in the double-bite arm was significantly smaller than in single-bite arm (2.5 mm vs. 3.0 mm; P < 0.001) but this did not affect the presence of muscularis mucosa (P = 0.73), artifact level (P = 0.11), and diagnostic utility (P = 0.051). CONCLUSION : For patients undergoing HDGC surveillance, the double-bite technique is significantly faster than the single-bite technique. The diagnostic yield for SRCC and the biopsy quality were similar across both groups.

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.

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.

Impact of Primary Disease Nature in the Development of De Novo Donor-Specific Antibodies After Kidney Transplant and the Risk of Acute Rejection.

OBJECTIVES: In this study, we explored the effect of the primary disease nature on development of de novo donor-specific antibodies after kidney transplant. MATERIALS AND METHODS: We retrospectively studied kidney transplant recipients based on their primary disease. Patients were divided according to autoimmune and nonautoimmune diseases. The frequency of de novo donor-specific antibodies posttransplant and the incidence of acute rejection were estimated. De novo donor-specific antibodies were determined by the Luminex (LAB Screen products, One Lambda, Inc., Canoga Park, CA, USA) assay. RESULTS: Our study included 228 patients: 92 with autoimmune diseases and 136 with nonautoimmune diseases. Similar rates of de novo donor-specific antibodies (10.9% vs 11.8%; P = .835) were shown in the 2 groups over a mean (standard deviation) follow-up of 56.5 (27.8) months. In the nonautoimmune group, presence of de novo donor-specific antibodies was associated with higher rates of biopsy-proven acute rejection (37.5% vs 8.3%; odds ratio = 6.6; 95% confidence interval, 1.985-21.945; P = .002) versus that shown in patients of the same group without de novo donor-specific antibodies. In the autoimmune group, biopsy-proven acute rejection rates were similar between patients with and without de novo donor-specific antibodies. Mean fluorescence intensity titers of de novo donor-specific antibodies were significantly higher in patients with nonautoimmune primary disease (P = .003).Overall, graft loss was shown to be significantly higher in patients with autoimmune than in patients with nonautoimmune diseases (P < .001), although not different between patients with de novo donor-specific antibody formation (P = .677). CONCLUSIONS: No associations were shown between the frequency of de novo donor-specific antibody development after kidney transplant and the nature of the primary disease (autoimmune vs nonautoimmune). Detection of de novo donor-specific antibodies was associated with higher rates of biopsy-proven acute rejection among patients with nonautoimmune primary disease.

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.

Assessing the clinical utility of Wnt pathway markers in colorectal cancer.

PURPOSE: ß-catenin and AXIN2 play an important role in the Wnt signaling pathway. The aim of this study was to investigate ß-catenin and AXIN2 expression in colorectal cancer (CRC) and relate these findings with patients' clinicopathological features and prognosis. METHODS: 57 consecutive patients with surgically treated CRC were included in this study. Quantitative PCR and immunohistochemistry (IHC) analyses were performed to characterize the expression of the aforementioned markers in CRC tissues. RESULTS: ß-catenin overexpression in the nucleus was associated with advanced N stage CRCs (p=0.04). Multivariate Cox regression analysis showed that ß-catenin overexpression is an independent prognostic factor for overall survival (OS). A positive correlation between ß-catenin location and AXIN2 mRNA was observed. CONCLUSIONS: Nuclear ß-catenin is a valuable prognostic factor. AXIN2 is a component of the "Destruction Complex" and also a Wnt target gene. However, the clinical importance of AXIN2 expression in CRC remains unclear.

The Kollias legacy: Skin autofluorescence and beyond.

In a paper published at the J Invest Dermatol in 1998 Nik Kollias and coworkers described distinct changes in skin native fluorescence associated with skin aging and photoaging, using in vivo fluorescence excitation spectroscopy. The assignment of the 295 nm band to tryptophan fluorescence had a profound significance influencing many later studies from multiple groups. The reproducible changes in skin native fluorescence suggested that aging causes predictable alterations in both the epidermis and the dermis, whereas chronic UV exposure induces the appearance of new fluorophores. This seminal, but insufficiently widely appreciated work deserves re-examination as it points to important horizons in future experimental dermatology, such as cancer diagnostics, diabetes, wound healing, and understanding skin aging and photoaging mechanisms.

Lymphovascular infiltration in the tumor bed is a useful marker of biological behavior in breast cancer.

PURPOSE: Tumor cells can metastasize by entering existing vessels or new vessels actively recruited into the primary tumor. Invasion of the lymphatics and blood vessels in the periphery of the tumor seems to be a prerequisite step in the metastatic process. The aim of this study was to correlate peripheral lymphatic vessel infiltration (PLI) and peripheral blood vessel infiltration (PVI) in a cohort of patients with invasive ductal carcinoma of the breast with various other prognostic parameters and outcome. METHODS: The study population consisted of 236 female patients with invasive ductal breast carcinomas, who had been operated between 2011 and 2013. The registered data included age at diagnosis, histological subtype, tumor size, TNM stage, histological grade, estrogen (ER) and progesterone receptors (PR), HER-2, p53, and PLI and PVI. RESULTS: Pathological examination revealed that 22.5% of the patients had PVI and 37.3% had PLI at the tumor front. PVI correlated with younger age (p<0.05), higher histologic grade (p<0.05), advanced TNM stage (p<0.05), higher T stage (p<0.05), higher N stage (p<0.05) and positive Ki67 expression (p<0.05). Similarly, PLI correlated with higher histologic grade (p<0.05), advanced TNM stage (p<0.05), higher T stage (p<0.05) and higher N stage (p<0.05). Statistical analysis did not reveal significant correlation between the presence of tumor blood and lymphatic vessels with infiltration in overall (OS) and disease-free survival (DFS). CONCLUSIONS: PLI and PVI are important markers of worse clinical outcome as shown by their association with other established factors, but no association with recurrence and survival could be proven.

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.

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.