The type B trichothecene mycotoxins deoxynivalenol (DON), nivalenol (NIV) and fusarenon-X (FX) are structurally related secondary metabolites frequently produced by Fusarium on wheat. Consequently, DON, NIV and FX contaminate wheat dusts, exposing grain workers to toxins by inhalation. Those trichothecenes at low, relevant, exposition concentrations have differential effects on intestinal cells, but whether such differences exist with respiratory cells is mostly unknown, while it is required to assess the combined risk of exposure to mycotoxins. The goal of the present study was to compare the effects of DON, NIV and FX alone or in combination on the viability and IL-6 and IL-8-inducing capacity of human epithelial cells representative of the respiratory tract: primary human airway epithelial cells of nasal (hAECN) and bronchial (hAECB) origin, and immortalized human bronchial (16HBE14o-) and alveolar (A549) epithelial cell lines. We report that A549 cells are particularly resistant to the cytotoxic effects of mycotoxins. FX is more toxic than DON and NIV for all epithelial cell types. Nasal and bronchial primary cells are more sensitive than bronchial and alveolar cell lines to combined mycotoxin mixtures at low concentrations, although they are less sensitive to mycotoxins alone. Interactions between mycotoxins at low concentrations are rarely additive and are observed only for DON/NIV and NIV/FX on hAECB cells and DON/NIV/FX on A549 cells. Most interactions at low mycotoxin concentrations are synergistic, antagonistic interactions being observed only for DON/FX on hAECB, DON/NIV on 16HBE14o- and NIV/FX on A549 cells. DON, NIV and FX induce, albeit at different levels, IL-6 and IL-8 release by all cell types. However, NIV and FX at concentrations of low cytotoxicity induce IL-6 release by hAECB and A549 cells, and IL-8 release by hAECN cells. Overall, these data suggest that combined exposure to mycotoxins at low concentrations have a stronger effect on primary nasal epithelial cells than on bronchial epithelial cells and activate different inflammatory pathways. This information is particularly relevant for future studies about the hazard of occupational exposure to mycotoxins by inhalation and its impact on the respiratory tract.

Therapy by adoptive transfer of ex vivo-expanded tumor-infiltrating or genetically modified T cells may lead to impressive clinical responses. However, there is a need to improve in vivo persistence and functionality of the transferred T cells, in particular, to face the highly immunosuppressive environment of solid tumors. Here, we investigate the potential of miR-155, a microRNA known to play an important role in CD8 + T cell fitness. We show that forced expression of miR-155 in tumor antigen-specific T cells improves the tumor control of B16 tumors expressing a low-affinity antigen ligand. Importantly, miR-155-transduced T cells exhibit increased proliferation and effector functions associated with a higher glycolytic activity independent of exogenous glucose. Altogether, these data suggest that miR-155 may optimize the antitumor activity of adoptively transferred low-affinity tumor-infiltrating lymphocytes (TILs), in particular, by rendering them more resistant to the glucose-deprived environment of solid tumors. Thus, transgenic expression of miR-155 may enable therapeutic targeting of self-antigen-specific T cells in addition to neoantigen-specific ones.

Sustained expression of FOXM1 is a hallmark of nearly all human cancers including squamous cell carcinomas of the head and neck (HNSCC). HNSCCs partially preserve the epithelial differentiation program, which recapitulates fetal and adult traits of the tissue of tumor origin but is deregulated by genetic alterations and tumor-supporting pathways. Using shRNA-mediated knockdown, we demonstrate a minimal impact of FOXM1 on proliferation and migration of HNSCC cell lines under standard cell culture conditions. However, FOXM1 knockdown in three-dimensional (3D) culture and xenograft tumor models resulted in reduced proliferation, decreased invasion, and a more differentiated-like phenotype, indicating a context-dependent modulation of FOXM1 activity in HNSCC cells. By ectopic overexpression of FOXM1 in HNSCC cell lines, we demonstrate a reduced expression of cutaneous-type keratin K1 and involucrin as a marker of squamous differentiation, supporting the role of FOXM1 in modulation of aberrant differentiation in HNSCC. Thus, our data provide a strong rationale for targeting FOXM1 in HNSCC.No conflicts of interest were declared. heterogeneous expression of keratins [10][11][12].Despite a large body of evidence that FOXM1 has a role in HNSCC [13][14][15][16], its oncogenic functions in this type of cancer are not yet sufficiently understood. In Figure 3. shRNA-mediated FOXM1 knockdown decreases the number of proliferating cells and facilitates progression towards a more differentiated-like phenotype. (A) H&E staining of CAL27 organotypic cultures demonstrating a squamous-like phenotype after 16 days of culture. Scale bar = 100 μm. (B) Representative pictures of immunostaining for a series of indicated differentiation markers in CAL27 organotypic cultures at day 16. Scale bar = 100 μm. (C) RT-qPCR analysis of organotypes showing a gradual decrease in FOXM1 and its targets CCNF and GTSE1 upon FOXM1 knockdown, while differentiation-related genes such as JUND and IVL were upregulated both by FOXM1 knockdown and by increased time of culture. The data shown are from one experiment. (D) RT-qPCR analysis of FOXM1 and IVL expression levels in a large series of CAL27 shCtr or shFOXM1 organotypic cultures showing a trend for IVL upregulation following FOXM1 knockdown. Each dot represents one organotype. (E) FOXM1 expression was reduced by culturing cells in 3D organotypes as demonstrated by the reduction of FOXM1 transcript level measured by RT-qPCR. Each data point represents one sample under one condition or the other. (F) Computer-assisted quantification of the number of Ki-67-positive cells detected by immunohistochemistry in shCtr and FOXM1-depleted organotypes. Each data point represents one analyzed field of the organotype. (G) Examples for the Ki-67 immunohistochemistry data quantified in panel F. Ki-67-positive cells were detected in the basal layer for both conditions at day 8. In the control, cycling cells were present throughout the organotype at day 16, while they were restricted to the basal layer upon FOXM1 downregu...

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