Dendritic cells in Barrett's esophagus carcinogenesis: an inadequate microenvironment for antitumor immunity?

in American Journal of Pathology (in press)

Tumor microenvironment converts plasmacytoid dendritic cells into immunosuppressive/tolerogenic cells: insight into the molecular mechanisms

in Journal of Leukocyte Biology (2013), 93

Human pDCs represent a rare population of circulating cells characterized by a rapid and massive TLR-dependent secretion of type I IFN in response to pathogenic agents or danger signals. Through their ... [more ▼]

Human pDCs represent a rare population of circulating cells characterized by a rapid and massive TLR-dependent secretion of type I IFN in response to pathogenic agents or danger signals. Through their capacity to bring together innate and adaptive immunity and to secrete soluble factors controlling cancer development, these cells could represent important actors in antitumor immunity. However, accumulating evidence suggests that pDCs recruited to the tumor microenvironment often display a nonactivated state and are associated with the development and maintenance of immunosuppression. Here, we present an overview of neoplastic lesions associated with an infiltration of immunosuppressive/ tolerogenic pDC. Moreover, as the proper response of pDC against cancer depends on a critical balance between immune-activating and immune-suppressing mechanisms, we summarize current knowledge about the molecular pathways developed by tumors to prevent antitumoral pDC immune responses. A better understanding of the mechanisms regulating pDC function in tumors could aid in the development of new therapies. Indeed, effective cancer vaccines or therapies could combine immunoactivating strategies (i.e., TLR agonists) with elimination of immune-suppressing mechanisms, leading to pDC reprogramming and thus, allowing tumor rejection in a clinical setting. [less ▲]

Expression of type 2 orexin receptor in human endometrium and its epigenetic silencing in endometrial cancer.

in Journal of Clinical Endocrinology and Metabolism (2013), 98(4), 1549-57

CONTEXT: Orexins A and B are neuropeptides that bind and activate 2 types of receptors. In addition to direct action in the brain, the orexinergic system has broader implications in peripheral organs, and ... [more ▼]

CONTEXT: Orexins A and B are neuropeptides that bind and activate 2 types of receptors. In addition to direct action in the brain, the orexinergic system has broader implications in peripheral organs, and it has been proposed to have a role in the induction of apoptosis. There are very few data on the endometrium. OBJECTIVE: The expression and epigenetic regulation of type 2 orexin receptor (OX2R) was investigated in the human endometrium as well as in endometrial endometrioid carcinoma (EEC). METHODS: OX2R localization was studied by immunohistochemistry in normal endometrium (n = 24) and in EEC (n = 32). The DNA methylation status of a CpG island located in the first exon of OX2R was analyzed by bisulfite sequencing in normal (n = 18), EEC (n = 34), and 3 endometrial cell lines. On the latter, mRNA expression and Western blotting as well as in vitro induction with orexin were performed. RESULTS: Expression of the OX2R protein was detected in normal endometrial epithelia, whereas it was frequently lacking in EEC. This loss was associated with hypermethylation of OX2R in EEC in comparison with normal endometrium (median CpG methylation percentages of 48.85% and 5.85%, respectively). In cell lines, hypermethylation correlated with weak OX2R expression. Additionally, in vitro treatment of the 3 EEC cell lines with orexins A and B did not result in proliferation change CONCLUSIONS: Altogether our data provide evidence for the epigenetic silencing of OX2R in EEC. The implication of the OX2R loss in tumoral progression remains to be elucidated. [less ▲]

Novel cooperation between CX3CL1 and CCL26 inducing NK cell chemotaxis via CX3CR1: a possible mechanism for NK cell infiltration of the allergic nasal tissue.

in Clinical & Experimental Allergy : Journal of the British Society for Allergy & Clinical Immunology (2013), 43(3), 322-31

BACKGROUND: Recent data indicated that natural killer (NK) cells and chemokines could play a pivotal role in nasal inflammation. CX3CR1, the only receptor for fractalkine/CX3CL1, is abundantly expressed ... [more ▼]

BACKGROUND: Recent data indicated that natural killer (NK) cells and chemokines could play a pivotal role in nasal inflammation. CX3CR1, the only receptor for fractalkine/CX3CL1, is abundantly expressed by NK cells, and was recently shown to also be a receptor for eotaxin-3/CCL26. However, no reports explored the NK cells-CX3CL1-CCL26 axis via CX3CR1 in allergy. OBJECTIVE: Our goals were first to determine specifically NK cell recruitment pattern in nasal tissue of allergic chronic rhinosinusitis (ACRS) and non-allergic chronic rhinosinusitis (NACRS) patients in comparison with healthy controls, and secondly, to investigate the function of CX3CR1 in NK cell migration. METHODS: Immunohistochemistry, microchemotaxis chambers, flow cytometry and confocal microscopy were used in this study. RESULTS: Herein, we showed that NK cells infiltrated the epithelial layers of nasal tissue only in ACRS patients and not in NACRS patients or controls. NK cells were also more numerous in the stroma of the nasal tissue from ACRS patients compared with NACRS patients or controls. This migration could be mediated by both CX3CL1 and CCL26, as these two chemokines induced NK cell migration. Moreover, both molecules also stimulated cytoskeleton changes and F-actin reorganisation in NK cells. Chemotaxis and cytoskeleton changes were sensitive to genistein, a tyrosine kinase inhibitor. By flow cytometry, we demonstrated that a single antigen nasal provocation challenge increased the expression of CX3CR1 on NK cells in allergic rhinitis (AR) patients. The function of this receptor was associated with a significant augmentation of NK cell chemotaxis against the optimal doses of CX3CL1 and CCL26. CONCLUSIONS AND CLINICAL RELEVANCE: Our results highlight a novel role for CX3CR1 in NK cell migration that may contribute to the NK cell trafficking to the allergic upper airway. This could be mediated largely by CX3CL1 and CCL26 stimulation of the tyrosine kinase pathway. [less ▲]

Evaluation of a new biocompatible poly(N-(morpholino ethyl methacrylate)-based copolymer for the delivery of ruthenium oligonucleotides, targeting HPV16 E6 oncogene

in Journal of Biomedical Nanotechnology (2013), 9

This study investigates the use of a new biocompatible block copolymer poly(2-(dimethylamino)ethyl methacrylate-N-(morpholino)ethyl methacrylate (PDMAEMA-b-PMEMA) for the delivery of a particular ... [more ▼]

This study investigates the use of a new biocompatible block copolymer poly(2-(dimethylamino)ethyl methacrylate-N-(morpholino)ethyl methacrylate (PDMAEMA-b-PMEMA) for the delivery of a particular antisense oligonucleotide targeting E6 gene from human papilloma virus. This antisense oligonucleotide was derivatized with a polyazaaromatic RuII complex which, under visible illumination, is able to produce an irreversible crosslink with the complementary targeted sequence. The purpose of this study is to determine whether by the use of a suitable transfection agent, it is possible to increase the efficiency of the antisense oligonucleotide targeting E6 gene, named Ru-P-4. In a recent study, we showed that Oligofectamine® transfected Ru-P-4 antisense oligonucleotide failed to inhibit efficiently the growth of cervical cancer cell line SiHa, contrarily to the Ru-P-6 antisense oligonucleotide, another sequence also targeting the E6 gene. The ability of PDMAEMA-b-PMEMA to form polyplexes with optimal physicochemical characteristics was investigated first. Then the ability of the PDMAEMA-b-PMEMA/Ru-P-4 antisense oligonucleotide polyplexes to transfect two keratinocyte cell lines (SiHa and HaCat) and the capacity of polyplexes to inhibit HPV16 + cervical cancer cell growth was evaluated. PDMAEMA-b-PMEMA base polyplexes at the optimal molar ratio of polymer nitrogen atoms to DNA phosphates (N/P), were able to deliver Ru-P-4 antisense oligonucleotide and to induce a higher growth inhibition in human cervical cancer SiHa cells, compared to other formulations based on Oligofectamine®. [less ▲]

Interleukin-32 expression is associated with a poorer prognosis in head and neck squamous cell carcinoma.

in Molecular Carcinogenesis (2013)

Head and neck squamous cell carcinoma (HNSCC) represent the sixth most common malignancy diagnosed worldwide. Patient's survival is low due the high frequency of tumor recurrence. Inflammation promotes ... [more ▼]

Head and neck squamous cell carcinoma (HNSCC) represent the sixth most common malignancy diagnosed worldwide. Patient's survival is low due the high frequency of tumor recurrence. Inflammation promotes carcinogenesis as well as the formation of metastasis. Indeed, proinflammatory mediators are known to stimulate the expression of specific transcription factors such as Snai1 and to increase the ability of tumor cells to migrate into distant organs. The atypical interleukin-32 (IL32) was mainly described to exacerbate inflammatory responses in rheumatoid arthritis and inflammatory bowel diseases. IL32 is expressed in various cancers but its role in HNSCC physiology is still unexplored. Here, we analyzed the expression of IL32 and its implication on HNSCC aggressiveness. We showed that patients with tumor expressing high amounts of IL32 exhibit decreased disease-free periods (20.5 mo vs. 41 mo, P = 0.0041) and overall survival (P = 0.0359) in comparison with individuals with weak IL32 tumor expression. This overexpression was negatively correlated with gender (P = 0.0292) and p53 expression (P = 0.0307). In addition, in vitro data linked IL32 expression to metastasis formation since IL32 inhibition decreased Snai1 expression and tumor cell migration in a Boyden chamber assay. Our data provide new insight into the role of IL32 in HNSCC aggressiveness. (c) 2013 Wiley Periodicals, Inc. [less ▲]

Oncogenic human papillomavirus could directly interact with Natural Killer cells

Poster (2012, December 10)

Infusion of third party mesenchymal stem cells (MSC) after kidney and liver transplantation: a phase I-II, open-label, clinical study

Conference (2012, October 19)

MSC cells have demonstrated significant immunosuppressive effects in various in vivo and in vitro studies. This study aims to be the first evaluation of the safety and tolerability of third party MSC ... [more ▼]

MSC cells have demonstrated significant immunosuppressive effects in various in vivo and in vitro studies. This study aims to be the first evaluation of the safety and tolerability of third party MSC infusion after cadaveric kidney and liver transplantation in a prospective phase I-II study, taking advantage of our centre expertise and experience in MSC use in graft-versus-host disease (GVHD) after bone marrow transplantation and using an already functioning GMP-compliant laboratory producing clinical-grade MSC. Secondary end-points will help to evaluate the immunosuppressive potential of MSC after organ transplantation, and the opportunity to develop larger randomised, controlled, phase III trials. After successful transplantation, 10 liver and 10 kidney transplant recipients under standard immunosuppression (tacrolimus, MMF, steroids) will receive an intravenous infusion of 1.5-3x106/kg of third-party MSC on post-operative day 3±2. These patients will be prospectively compared to 10 liver and 10 kidney recipients who meet the inclusion criteria but deny MSC infusion. Safety will be assessed by recording side effects, including opportunistic infections and cancers. Immunosuppressive potential will be evaluated by rejection episode rates, by graft/patient survivals, by immunohistology of 3-months kidney and 6-month liver graft biopsies and by in vitro evaluation of the immunity profile of the recipients. In a second step, reduction (kidney) and progressive weaning (liver) of immunosuppression will be attempted in recipients who received MSC. This ongoing study is supported by research grants from the CHU of Liège, University of Liège, and by the Senior Clinical Research Grant from ESOT. The first patients were included and treated in early 2012, and final results expected in late 2013. [less ▲]

Human papillomavirus capsids trigger crosstalk between dendritic and NK cells

Poster (2012, September 26)

The immune system controls, at least partially, human papillomavirus (HPV) infection and subsequent tumour development as demonstrated by a higher tumour prevalence in immunodeficient patients. More than ... [more ▼]

The immune system controls, at least partially, human papillomavirus (HPV) infection and subsequent tumour development as demonstrated by a higher tumour prevalence in immunodeficient patients. More than 90% of HPV-infected women will clear the virus within two years. However, it remains unclear which immune cells are implicated in this process and although dendritic cells (DC) and NK cells play a key role in host resistance to virus and tumour, no study has been performed evaluating their crosstalk in this context. Virus-like particles (VLP) formed by the HPV major capsid protein L1 are licensed as vaccine against cervical cancer and we have recently shown that NK cells can directly interact with these HPV-VLP [1]. Here, we investigated the impact of this activation on NK-DC crosstalk. Interestingly, NK cells increase DC maturation induced by HPV-VLP as shown by an up-regulation of HLA-DR and CD86 on DC. Transwell experiments indicated that the expression of HLA-DR is cell-cell contact and soluble factor dependent, whereas only soluble factors seem to be required for CD86 expression. Moreover, in the presence of HPV-VLP and NK cells, DC produce higher amounts of IL12p70, while the production of the immunosuppressive cytokine IL10 remains unchanged. We also demonstrated that DC can up-regulate the expression of NK activation markers (CD69 and HLA-DR) in the presence of HPV-VLP. This up-regulation requires both cell-cell contact and soluble factors. Regarding HLA-DR marker, the increased expression on CD56bright cells is mediated by soluble factors, whereas cell-cell contacts are also important for HLA-DR expression on CD56dim cells. In the presence of DC activated by HPV-VLP, the function of NK cells is also modified since they become more cytotoxic against HPV+ cell line and secrete more IFN-γ. Our results suggest that NK-DC crosstalk could play a role in the immune response induced by HPV-VLP during vaccination protocols against cervical cancer. [less ▲]

The human papillomavirus (HPV) vaccine induces collaboration between dendritic cells and natural killer cells in vitro

Conference (2012, June 22)