Assessment of interferon-γ in pleural fluid as a prognostic factor of survival in malignant pleural mesothelioma.

BACKGOUND: Literature reports suggest that the host immune system may control Malignant Pleural Mesothelioma (MPM) growth, although its activity is limited by regulatory mechanisms. In this retrospective study, we analyzed the levels of pro-inflammatory (IL-1, IL-6, TNF), immune-regulatory (IL-10) and Th1/CTL-related cytokines (IL-12p70, IFN-γ) in the pleural exudate and their relationship with overall survival (OS) in MPM. METHODS: Cytokines were quantified by multiplexed immunoassay. Concentrations were dichotomized with respect to the median value. Correlation between cytokine level and OS was assessed using univariate (Kaplan-Meier curves) and multivariate (Cox regression) analyses. RESULTS: Regarding outcome, tumor histology, therapies undergone and IFN-γ were independent prognostic factors of OS in a 72 MPM training cohort. Notably, high concentrations of IFN-γ halved death probability (HR of high vs low IFN-γ concentration = 0.491, 95%CI 0.3-0.8, p = 0.007). Also in patients with epithelioid histology and those receiving at least one line of therapy, high IFN-γ level was an independent factor predictive of OS (HR of high vs low IFN-γ concentration were 0.497, p = 0.007 and 0.324, p = 0.006, respectively). However, these data were not confirmed in a 77 MPM validation cohort, possibly due to the low IFN-γ levels encountered in this population, and the heterogeneous distribution of disease stages between the training and the validation cohorts. None of the other cytokines showed any effect on survival. CONCLUSIONS: High level of IFN-γ in pleural effusion may be associated with better survival in MPM patients and potentially serve as a prognostic biomarker. Larger prospective studies are needed to ascertain this hypothesis.

The biology of uveal melanoma.

Uveal melanoma (UM), a rare cancer of the eye, is distinct from cutaneous melanoma by its etiology, the mutation frequency and profile, and its clinical behavior including resistance to targeted therapy and immune checkpoint blockers. Primary disease is efficiently controlled by surgery or radiation therapy, but about half of UMs develop distant metastasis mostly to the liver. Survival of patients with metastasis is below 1 year and has not improved in decades. Recent years have brought a deep understanding of UM biology characterized by initiating mutations in the G proteins GNAQ and GNA11. Cytogenetic alterations, in particular monosomy of chromosome 3 and amplification of the long arm of chromosome 8, and mutation of the BRCA1-associated protein 1, BAP1, a tumor suppressor gene, or the splicing factor SF3B1 determine UM metastasis. Cytogenetic and molecular profiling allow for a very precise prognostication that is still not matched by efficacious adjuvant therapies. G protein signaling has been shown to activate the YAP/TAZ pathway independent of HIPPO, and conventional signaling via the mitogen-activated kinase pathway probably also contributes to UM development and progression. Several lines of evidence indicate that inflammation and macrophages play a pro-tumor role in UM and in its hepatic metastases. UM cells benefit from the immune privilege in the eye and may adopt several mechanisms involved in this privilege for tumor escape that act even after leaving the niche. Here, we review the current knowledge of the biology of UM and discuss recent approaches to UM treatment.

Dual Roles of IL-27 in Cancer Biology and Immunotherapy.

IL-27 is a pleiotropic two-chain cytokine, composed of EBI3 and IL-27p28 subunits, which is structurally related to both IL-12 and IL-6 cytokine families. IL-27 acts through a heterodimer receptor consisting of IL-27Rα (WSX1) and gp130 chains, which mediate signaling predominantly through STAT1 and STAT3. IL-27 was initially reported as an immune-enhancing cytokine that supports CD4+ T cell proliferation, T helper (Th)1 cell differentiation, and IFN-γ production, acting in concert with IL-12. However, subsequent studies demonstrated that IL-27 displays complex immune-regulatory functions, which may result in either proinflammatory or anti-inflammatory effects in relationship to the biological context and experimental models considered. Several pieces of evidence, obtained in preclinical tumor models, indicated that IL-27 has a potent antitumor activity, related not only to the induction of tumor-specific Th1 and cytotoxic T lymphocyte (CTL) responses but also to direct inhibitory effects on tumor cell proliferation, survival, invasiveness, and angiogenic potential. Nonetheless, given its immune-regulatory functions, the effects of IL-27 on cancer may be dual and protumor effects may also occur. Here, we will summarize IL-27 biological activities and its functional overlaps with the IFNs and discuss its dual role in tumors in the light of potential applications to cancer immunotherapy.

Recombinant IL-21 and anti-CD4 antibodies cooperate in syngeneic neuroblastoma immunotherapy and mediate long-lasting immunity.

IL-21 is an immune-enhancing cytokine, which showed promising results in cancer immunotherapy. We previously observed that the administration of anti-CD4 cell-depleting antibody strongly enhanced the anti-tumor effects of an IL-21-engineered neuroblastoma (NB) cell vaccine. Here, we studied the therapeutic effects of a combination of recombinant (r) IL-21 and anti-CD4 monoclonal antibodies (mAb) in a syngeneic model of disseminated NB. Subcutaneous rIL-21 therapy at 0.5 or 1 µg/dose (at days 2, 6, 9, 13 and 15 after NB induction) had a limited effect on NB development. However, coadministration of rIL-21 at the two dose levels and a cell-depleting anti-CD4 mAb cured 28 and 70 % of mice, respectively. Combined immunotherapy was also effective if started 7 days after NB implant, resulting in a 30 % cure rate. Anti-CD4 antibody treatment efficiently depleted CD4(+) CD25(high) Treg cells, but alone had limited impact on NB. Combination immunotherapy by anti-CD4 mAb and rIL-21 induced a CD8(+) cytotoxic T lymphocyte response, which resulted in tumor eradication and long-lasting immunity. CD4(+) T cells, which re-populated mice after combination immunotherapy, were required for immunity to NB antigens as indicated by CD4(+) T cell depletion and re-challenge experiments. In conclusion, these data support a role for regulatory CD4(+) T cells in a syngeneic NB model and suggest that rIL-21 combined with CD4(+) T cell depletion reprograms CD4(+) T cells from immune regulatory to anti-tumor functions. These observations open new perspectives for the use of IL-21-based immunotherapy in conjunction with transient CD4(+) T cell depletion, in human metastatic NB.

Drug delivery with a calixpyrrole--trans-Pt(II) complex.

A meso-p-nitroaniline-calix[4]pyrrole derivative trans-coordinated to a Pt(II) center was synthesized and its structure solved by X-ray analysis. Adenosine monophosphate (AMP) was used as a model compound to evaluate the potential for the assisted delivery of the metal to the DNA nucleobases via the phosphate anion-binding properties of the calix[4]pyrrole unit. An NMR investigation of the kinetics of AMP complexation in the absence of an H-bonding competing solvent (dry CD(3)CN) was consistent with this hypothesis, but we could not detect the interaction of the calix[4]pyrrole with phosphate in the presence of water. However, in vitro tests of the new trans-calixpyrrole-Pt(II) complex on different cancer cell lines indicate a cytotoxic activity that is unquestionably derived from the coexistence of both the trans-Pt(II) fragment and the calix[4]pyrrole unit.

Activated leukocyte cell adhesion molecule soluble form: a potential biomarker of epithelial ovarian cancer is increased in type II tumors.

Activated leukocyte cell adhesion molecule (ALCAM) is involved in cell-cell interactions in cancer. Shedding of its ectodomain by the metalloprotease ADAM17/TACE generates a soluble form (sALCAM). Here, we show that serum sALCAM levels were significantly higher in epithelial ovarian cancer (EOC) (p < 0.005) than in controls. The performance of sALCAM as classifier, tested by receiver operating characteristic curve, resulted in an area under the curve (AUC) of 0.8067. Serum sALCAM levels showed direct correlation with Carbohydrate Antigen-125 (CA125/MUC16). Moreover, significantly higher levels were found in type II tumors, even in stage I/II, suggesting that elevated sALCAM is an early feature of aggressive EOC. In addition, sALCAM levels were higher in ascites than in sera, suggesting local processing of ALCAM in the peritoneal cavity. In immunodeficient mice, intraperitoneally implanted with a human EOC cell line, human sALCAM progressively increased in serum and was even higher in the ascites. The biochemical characterization of the sALCAM in EOC sera and ascites, showed two predominant forms of approximately 95 and 65 kDa but no EOC-specific isoform. In addition, full-length transmembrane ALCAM but no soluble form was detected in tumor-derived exosomes found in ascites. Finally, in vitro invasion assays showed that inhibition of ADAM17/TACE activity decreased EOC invasive properties, while opposite effects were mediated by a sALCAM-Fc chimera and by an antibody interfering with ALCAM/ALCAM interactions. Altogether these data suggest that sALCAM is a marker of EOC, which correlates with more aggressive type II tumors, and that ADAM17/TACE activity and sALCAM itself mediate enhanced invasiveness.

Neutralization of NET-associated human ARG1 enhances cancer immunotherapy.

Myeloid cells can restrain antitumor immunity by metabolic pathways, such as the degradation of l-arginine, whose concentrations are regulated by the arginase 1 (ARG1) enzyme. Results from preclinical studies indicate the important role of arginine metabolism in pancreatic ductal adenocarcinoma (PDAC) progression, suggesting a potential for clinical application; however, divergent evolution in ARG1 expression and function in rodents and humans has restricted clinical translation. To overcome this dichotomy, here, we show that neutrophil extracellular traps (NETs), released by spontaneously activated neutrophils isolated from patients with PDAC, create a microdomain where cathepsin S (CTSS) cleaves human (h)ARG1 into different molecular forms endowed with enhanced enzymatic activity at physiological pH. NET-associated hARG1 suppresses T lymphocytes whose proliferation is restored by either adding a hARG1-specific monoclonal antibody (mAb) or preventing CTSS-mediated cleavage, whereas small-molecule inhibitors are not effective. We show that ARG1 blockade, combined with immune checkpoint inhibitors, can restore CD8+ T cell function in ex vivo PDAC tumors. Furthermore, anti-hARG1 mAbs increase the frequency of adoptively transferred tumor-specific CD8+ T cells in tumor and enhance the effectiveness of immune checkpoint therapy in humanized mice. Thus, this study shows that extracellular ARG1, released by activated myeloid cells, localizes in NETs, where it interacts with CTSS that in turn cleaves ARG1, producing major molecular forms endowed with different enzymatic activity at physiological pH. Once exocytosed, ARG1 activity can be targeted by mAbs, which bear potential for clinical application for the treatment of PDAC and require further exploration.

Analysis of A Disintegrin and Metalloprotease 17 (ADAM17) Expression as a Prognostic Marker in Ovarian Cancer Patients Undergoing First-Line Treatment Plus Bevacizumab.

To find prognostic factors for advanced ovarian cancer patients undergoing first-line therapy with carboplatin, paclitaxel and bevacizumab, we investigated the expression of a disintegrin and metalloprotease 17 (ADAM17) in cancer tissues. ADAM17 has been involved in ovarian cancer development, progression and cell resistance to cisplatin. Tissue microarrays from 309 ovarian cancer patients enrolled in the MITO16A/MANGO-OV2 clinical trial were analyzed by immunohistochemistry for ADAM17 protein expression. Intensity and extent of staining were combined into a semi-quantitative visual grading system (H score) which was related to clinicopathological characteristics of cases and the clinical outcome of patients by univariate and multivariate Cox regression models. ADAM17 immunostaining was detected in most samples, mainly localized in the tumor cells, with variable intensity across the cohort. Kaplan-Meier survival curves, generated according to the best cut-off value for the ADAM17 H score, showed that high ADAM17 expression was associated with worse prognosis for PFS and OS. However, after the application of a shrinkage procedure to adjust for overfitting hazard ratio estimates, the ADAM17 value as prognostic factor was lost. As subgroup analysis suggested that ADAM17 expression could be prognostically relevant in cases with no residual disease at baseline, further studies in this patient category may be worth planning.

Interleukin (IL)-18, a biomarker of human ovarian carcinoma, is predominantly released as biologically inactive precursor.

Interleukin (IL)-18 is a proinflammatory and immune-enhancing cytokine, which exerts antitumor effects in vivo, mediated by the induction of interferon (IFN)γ. We previously reported that IL-18 processing is defective in epithelial ovarian carcinoma (EOC) cells, which secrete an inactive precursor (pro-IL-18) in vitro. In addition, IL-18 was reported as a potential biomarker of EOC. Here, we further investigated its role as a serological marker in human EOC and addressed its possible biological activity in vivo. Our data indicate that immunoreactive IL-18 is increased in EOC patients' sera at diagnosis as compared with age-matched healthy women. IL-18 levels were higher in the ascitic fluids than in sera, suggesting a local production in the peritoneal cavity. Indeed, immunohistochemical analysis of tumors showed IL-18 expression in cytokeratine-positive neoplastic cells, although also scattered histiocytes and some lymphoid cells stained for IL-18. The detection of human IL-18 in sera and ascitic fluids of immunodeficient mice, orthotopically implanted with human EOC cells, further suggested that circulating IL-18 is tumor-derived. However, IL-18 is not an EOC specific biomarker, as increased serum levels were found also in some endometrial cancer patients. By means of a new monoclonal antibody, we characterized IL-18 present in the ascitic fluid as pro-IL-18, which is biologically inactive. Accordingly, IFNγ was not increased in EOC patients' sera and ascitic fluids and showed no correlation with IL-18 levels. Altogether these data indicate that IL-18 in EOC fluids is predominantly tumor-derived and that its lack of biological activity may represent a mechanism of tumor-escape.

An interaction between hepatocyte growth factor and its receptor (c-MET) prolongs the survival of chronic lymphocytic leukemic cells through STAT3 phosphorylation: a potential role of mesenchymal cells in the disease.

BACKGROUND: Chronic lymphocytic leukemia cells are characterized by an apparent longevity in vivo which is lost when they are cultured in vitro. Cellular interactions and factors provided by the microenvironment appear essential to cell survival and may protect leukemic cells from the cytotoxicity of conventional therapies. Understanding the cross-talk between leukemic cells and stroma is of interest for identifying signals supporting disease progression and for developing novel therapeutic strategies. DESIGN AND METHODS: Different cell types, sharing a common mesenchymal origin and representative of various bone marrow components, were used to challenge the viability of leukemic cells in co-cultures and in contact-free culture systems. Using a bioinformatic approach we searched for genes shared by lineages prolonging leukemic cell survival and further analyzed their biological role in signal transduction experiments. RESULTS: Human bone marrow stromal cells, fibroblasts, trabecular bone-derived cells and an osteoblast-like cell line strongly enhanced survival of leukemic cells, while endothelial cells and chondrocytes did not. Gene expression profile analysis indicated two soluble factors, hepatocyte growth factor and CXCL12, as potentially involved. We demonstrated that hepatocyte growth factor and CXCL12 are produced only by mesenchymal lineages that sustain the survival of leukemic cells. Indeed chronic lymphocytic leukemic cells express a functional hepatocyte growth factor receptor (c-MET) and hepatocyte growth factor enhanced the viability of these cells through STAT3 phosphorylation, which was blocked by a c-MET tyrosine kinase inhibitor. The role of hepatocyte growth factor was confirmed by its short interfering RNA-mediated knock-down in mesenchymal cells. CONCLUSIONS: The finding that hepatocyte growth factor prolongs the survival of chronic lymphocytic leukemic cells is novel and we suggest that the interaction between hepatocyte growth factor-producing mesenchymal and neoplastic cells contributes to maintenance of the leukemic clone.

Role of common-gamma chain cytokines in NK cell development and function: perspectives for immunotherapy.

NK cells are components of the innate immunity system and play an important role as a first-line defense mechanism against viral infections and in tumor immune surveillance. Their development and their functional activities are controlled by several factors among which cytokines sharing the usage of the common cytokine-receptor gamma chain play a pivotal role. In particular, IL-2, IL-7, IL-15, and IL-21 are the members of this family predominantly involved in NK cell biology. In this paper, we will address their role in NK cell ontogeny, regulation of functional activities, development of specialized cell subsets, and acquisition of memory-like functions. Finally, the potential application of these cytokines as recombinant molecules to NK cell-based immunotherapy approaches will be discussed.

IL-27 Mediates PD-L1 Expression and Release by Human Mesothelioma Cells.

Malignant mesothelioma (MM) is a rare tumor with an unfavorable prognosis. MM genesis involves asbestos-mediated local inflammation, supported by several cytokines, including IL-6. Recent data showed that targeting PD-1/PD-L1 is an effective therapy in MM. Here, we investigated the effects of IL-6 trans-signaling and the IL-6-related cytokine IL-27 on human MM cells in vitro by Western blot analysis of STAT1/3 phosphorylation. The effects on PD-L1 expression were tested by qRT-PCR and flow-cytometry and the release of soluble (s)PD-L1 by ELISA. We also measured the concentrations of sPD-L1 and, by multiplexed immunoassay, IL-6 and IL-27 in pleural fluids obtained from 77 patients in relation to survival. IL-27 predominantly mediates STAT1 phosphorylation and increases PD-L1 gene and surface protein expression and sPD-L1 release by human MM cells in vitro. IL-6 has limited activity, whereas a sIL-6R/IL-6 chimeric protein mediates trans-signaling predominantly via STAT3 phosphorylation but has no effect on PD-L1 expression and release. IL-6, IL-27, and sPD-L1 are present in pleural fluids and show a negative correlation with overall survival, but only IL-27 shows a moderate albeit significant correlation with sPD-L1 levels. Altogether these data suggest a potential role of IL-27 in PD-L1-driven immune resistance in MM.

Shed HER2 extracellular domain in HER2-mediated tumor growth and in trastuzumab susceptibility.

The question of the serum HER2 extracellular domain (HER2/ECD) measurement for prediction of response to the anti-HER2 antibody Trastuzumab is still an open and current matter of clinical debate. To elucidate the involvement of shed HER2/ECD in HER2-driven tumor progression and in guiding therapy of individual patients, we examined biological effects exerted by elevated HER2/ECD in cancer growth and in response to Trastuzumab. To this purpose SKOV3 tumor cells were stably transfected to release a recombinant HER2/ECD molecule (rECD). Transfectants releasing high levels of 110-kDa rECD, identical in size to native HER2/ECD (nECD), grew significantly slower than did controls, which constitutively released only basal levels of nECD. While transmembrane HER2 and HER1 were expressed at equal levels by both controls and transfected cells, activation of these molecules and of downstream ERK2 and Akt was significantly reduced only in rECD transfectants. Surface plasmon resonance analysis revealed heterodimerization of the rECD with HER1, -2, and -3. In cell growth bioassays in vitro, shed HER2 significantly blocked HER2-driven tumor cell proliferation. In mice, high levels of circulating rECD significantly impaired HER2-driven SKOV3 tumor growth but not that of HER2-negative tumor cells. In vitro and in mice, Trastuzumab significantly inhibited tumor growth due to the rECD-facilitated accumulation of the antibody on tumor cells. Globally our findings sustain the biological relevance of elevated HER2/ECD levels in the outcome of HER2-disease and in the susceptibility to Trastuzumab-based therapy.

Transient depletion of CD4(+) T cells augments IL-21-based immunotherapy of disseminated neuroblastoma in syngeneic mice.

IL-21 is a member of the IL-2 cytokine family, produced by CD4+ T cells. We previously showed that immunotherapy (IT) with IL-21-transduced neuroblastoma cells (Neuro2a/IL-21) cured 33% of syngeneic mice bearing systemic NB. Here, we studied whether the removal of Treg cells could potentiate the therapeutic efficacy of Neuro2a/IL-21 vaccine. The administration of anti-CD25 mAb, which targets Treg cells, slightly potentiated the effect of vaccine IT (50% cure rate), but anti-CD4 mAb had a more potent effect leading to 80% cure rate. Anti-CD25 mAb, indeed, only partially depleted CD4+CD25+FoxP3+ Treg cells, whereas anti-CD4 mAb was more effective in this respect, leading to 90% depletion of Treg cells. In mice receiving vaccine+anti-CD4 mAb, which developed systemic immunity to NB, CD4+ T cells counts completely recovered in 90 days. Depletion of CD8+ T cells abrogated the effect of the combined IT, indicating a predominant role of these cells in driving the immune response. In addition, CD8+ T cells from cured mice coinjected with Neuro2a/parental cells (pc) in NOD-SCID mice completely inhibited tumor growth. Spleen cells from mice receiving Neuro2a/IL-21 vaccination showed increased expression of IFN-alpha2, -beta1 and -gamma mRNA. Moreover, mice receiving vaccine therapy alone or vaccine+anti-CD4 mAb showed increased IFN-gamma serum levels and IFN-gamma-producing CD8+ T cells were found in spleen cells. In conclusion, anti-CD4 mAb potentiated IL-21-based IT by removing Treg cells and/or their precursors and other potentially immune-suppressive CD4+ cell subsets, thus allowing the development of an IL-21-driven CD8+ T cell response, which mediates NB rejection.

Interferon gamma-induced human guanylate binding protein 1 inhibits mammary tumor growth in mice.

Interferon gamma (IFN-gamma) has recently been implicated in cancer immunosurveillance. Among the most abundant proteins induced by IFN-gamma are guanylate binding proteins (GBPs), which belong to the superfamily of large GTPases and are widely expressed in various species. Here, we investigated whether the well-known human GBP-1 (hGBP-1), which has been shown to exert antiangiogenic activities and was described as a prognostic marker in colorectal carcinomas, may contribute to an IFN-gamma-mediated tumor defense. To this end, an IFN-independent, inducible hGBP-1 expression system was established in murine mammary carcinoma (TS/A) cells, which were then transplanted into syngeneic immune-competent Balb/c mice. Animals carrying TS/A cells that had been given doxycycline for induction of hGBP-1 expression revealed a significantly reduced tumor growth compared with mock-treated mice. Immunohistochemical analysis of the respective tumors demonstrated a tightly regulated, high-level expression of hGBP-1. No signs of an enhanced immunosurveillance were observed by investigating the number of infiltrating B and T cells. However, hemoglobin levels as well as the number of proliferating tumor cells were shown to be significantly reduced in hGBP-1-expressing tumors. This finding corresponded to reduced amounts of vascular endothelial growth factor A (VEGF-A) released by hGBP-1-expressing TS/A cells in vitro and reduced VEGF-A protein levels in the corresponding mammary tumors in vivo. The results suggest that hGBP-1 may contribute to IFN-gamma-mediated antitumorigenic activities by inhibiting paracrine effects of tumor cells on angiogenesis. Consequently, owing to these activities GBPs might be considered as potent members in an innate, IFN-gamma-induced antitumoral defense system.

NK cells provide helper signal for CD8+ T cells by inducing the expression of membrane-bound IL-15 on DCs.

NK cell recognition of cells that do not express or express low amounts of MHC class I molecules results not only in direct killing of target cells but also in the generation of specific T cell responses consequent to the induction of dendritic cell (DC) activation. While IL-12 production by NK cell-activated DCs is generally thought to play a critical role, a similar DC-mediated NK cell help has been reported also in IL-12-knockout mice. Here, we show that human NK cells can induce on DC surface membrane, via IFN-gamma secretion, the expression of high levels of IL-15. Remarkably, we show that DC expression of this membrane-bound form of IL-15, which is only partially associated with IL-15R molecules, is essential to promote specific CD8(+) T lymphocyte response in the absence of DC-derived IL-12.

Strategies for improving the water solubility of new antitumour nitronaphthylbutadiene derivatives.

Different nitronaphthylbutadienes have been previously proved to have antitumour activity. The main drawback of these derivatives is their low water solubility. With the aim of facilitating the administration of these new drugs we have synthesized the hexyl (2Z,4E)-2-methylsulfanyl-5-(1-naphthyl)-4-nitro-2,4-pentadienoate analogue (1-Naph-NHCB) which is demonstrated to be easily included into cyclodextrins and/or entrapped into liposomes. Its antitumour activity was revealed to be almost comparable with that of the previously studied methyl analogue ester (1-Naph-NMCB). On the other hand, in vitro studies with different cancer cell lines showed that the cytotoxic activity of both 1-Naph-NMCB and 1-Naph-NHCB were fully preserved and in some cases also enhanced when entrapped into liposomal carriers.

Cytokine-Induced Guanylate Binding Protein 1 (GBP1) Release from Human Ovarian Cancer Cells.

We showed that IL-27 shares several effects with IFN-γ in human cancer cells. To identify novel extracellular mediators, potentially involved in epithelial ovarian cancer (EOC) biology, we analyzed the effect of IL-27 or IFN-γ on the secretome of cultured EOC cells by mass-spectrometry (nano-UHPLC-MS/MS). IL-27 and IFN-γ modulate the release of a limited fraction of proteins among those induced in the whole cell. We focused our attention on GBP1, a guanylate-binding protein and GTPase, which mediates several biological activities of IFNs. Cytokine treatment induced GBP1, 2, and 5 expressions in EOC cells, but only GBP1 was secreted. ELISA and immunoblotting showed that cytokine-stimulated EOC cells release full-length GBP1 in vitro, through non-classical pathways, not involving microvesicles. Importantly, full-length GBP1 accumulates in the ascites of most EOC patients and ex-vivo EOC cells show constitutive tyrosine-phosphorylated STAT1/3 proteins and GBP1 expression, supporting a role for Signal Transducer And Activator Of Transcription (STAT)-activating cytokines in vivo. High GBP1 gene expression correlates with better overall survival in the TCGA (The Cancer Genome Atlas) dataset of EOC. In addition, GBP1 transfection partially reduced EOC cell viability in an MTT assay. Our data show for the first time that cytokine-stimulated tumor cells release soluble GBP1 in vitro and in vivo and suggest that GBP1 may have anti-tumor effects in EOC.

Potential Onco-Suppressive Role of miR122 and miR144 in Uveal Melanoma through ADAM10 and C-Met Inhibition.

Uveal melanoma (UM) is a rare tumor of the eye that leads to deadly metastases in about half of the patients. ADAM10 correlates with c-Met expression in UM and high levels of both molecules are related to the development of metastases. MiR122 and miR144 modulate ADAM10 and c-Met expression in different settings. We hypothesized a potential onco-suppressive role for miR122 and miR144 through modulation of ADAM10 and c-Met in UM. We analyzed the UM Cancer Genome Atlas data portal (TCGA) dataset, two other cohorts of primary tumors and five human UM cell lines for miR122 and miR144 expression by miR microarray, RT-qPCR, Western blotting, miR transfection and luciferase reporter assay. Our results indicate that miR122 and miR144 are expressed at low levels in the UM cell lines and in the TCGA UM dataset and were down-modulated in a cohort of seven UM samples, compared to normal choroid. Both miR122 and miR144 directly targeted ADAM10 and c-Met. Overexpression of miR122 and miR144 led to reduced expression of ADAM10 and c-Met in the UM cell lines and impaired cell proliferation, migration, cell cycle and shedding of c-Met ecto-domain. Our results show that miR122 and miR144 display an onco-suppressive role in UM through ADAM10 and c-Met modulation.

IL-8 induces exocytosis of arginase 1 by neutrophil polymorphonuclears in nonsmall cell lung cancer.

Arginase 1 (ARG1) inhibits T-cell proliferation by degrading extracellular arginine, which results in decreased responsiveness of T cells to CD3/TCR stimulation. In humans, ARG1 is stored in inactive form within granules of polymorphonuclear neutrophils (PMNs) and gets activated on release. We studied the role of PMNs-related ARG1 activity in nonsmall cell lung cancer (NSLC), in which tumor-infiltrating lymphocytes showed reduced proliferation in response to CD3/TCR triggering. Patients with NSCLC had increased ARG1 plasma levels as compared to healthy controls. Furthermore, immunohistochemistry showed that tumor-infiltrating PMNs display reduced intracellular ARG1, in comparison to intravascular or peritumoral PMNs, suggesting a role of tumor microenvironment in ARG1 release. Indeed, supernatants of NSCLC cell lines induced exocytosis of ARG1 from PMNs. All (4/4) NSCLC cell lines and all (7/7) CD14- cell samples from NSCLC expressed interleukin (IL)-8 mRNA, whereas TNFalpha mRNA was expressed by 1 cell line and by 2 tumor specimens. Furthermore, all NSCLC cell lines secreted immunoreactive IL-8, albeit at different levels. IL-8 was as effective as TNFalpha in triggering ARG1 release and the 2 cytokines acted synergistically. Secreted ARG1 was biologically active and catabolized extracellular arginine. The supernatant of IL-8 gene-silenced NSCLC cells did not mediate ARG1 release by PMNs. Altogether these findings demonstrate a role of IL-8 in ARG1 exocytosis by PMNs and indicate that, due at least in part to IL-8 secreted by NSCLC cells, PMNs infiltrating NSCLC release ARG1. This phenomenon could contribute to local immune suppression.