Both, mast cells (MC) and regulatory T cells (Treg) have gained attention as immunosuppressive cell populations. To investigate a possible interaction, we used the Th1- and Th17-dependent model of nephrotoxic serum nephritis (NTS), in which both MC and Treg have been shown to play a protective role. Transfer of wild-type (wt) Treg into wt recipients almost completely prevents development of NTS and leads to a profound increase of MC in the renal draining lymph nodes (LN). By contrast, transfer of wt Treg into animals deficient in MC, which are characterized by an exaggerated susceptibility to NTS, no longer exhibited protective effects. Blocking the pleiotropic cytokine IL-9, known to be involved in MC recruitment and proliferation, by means of a monoclonal antibody in mice receiving Treg abrogated protection from NTS. Moreover, transfer of IL-9 deficient Treg also failed to protect from NTS. In the absence of Treg-derived IL-9, MC fail to accumulate in the LN, despite the fact that IL-9 deficiency does not alter the general suppressive activity of Treg. In summary, we provide the first direct in vivo evidence that the nephroprotective, anti-inflammatory effects of Treg cells critically depend on IL-9-mediated attraction of MC into kidney-draining LN.

IntroductionWe describe a novel 3D co-culture model using non-small cell lung cancer (NSCLC) cell lines in combination with lung fibroblasts. This model allows the investigation of tumour-stroma interactions and addresses the importance of having a more in vivo like cell culture model.MethodsAutomation-compatible multi-well hanging drop microtiter plates were used for the production of 3D mono- and co-cultures. In these hanging drops the two NSCLC cell lines A549 and Colo699 were cultivated either alone or co-cultured with lung fibroblasts. The viability of tumour spheroids was confirmed after five and ten days by using Annexin V/Propidium Iodide staining for flow-cytometry. Tumour fibroblast spheroid formation was characterized by scanning electron microscope (SEM), semi-thin sections, fluorescence microscope and immunohistochemistry (IHC). In addition to conventional histology, protein expression of E-Cadherin, vimentin, Ki67, fibronectin, cytokeratin 7 and α-smooth muscle actin (α-SMA) was investigated by IHC.ResultsLower viability was observed in A549 monocultures compared to co-cultures, whereas Colo699 monocultures showed better viability compared to co-cultures. Ki67 expression varied significantly between mono- and co-cultures in both tumour cell lines. An increase of vimentin and decreased E-Cadherin expression could be detected during the course of the cultivation suggesting a transition to a more mesenchymal phenotype. Furthermore, the fibroblast cell line showed an expression of α-SMA only in co-culture with the cancer cell line A549, thereby indicating a mesenchymal to mesenchymal shift to an even more myofibroblast phenotype.ConclusionWe demonstrate that our method is a promising tool for the generation of tumour spheroid co-cultures. Furthermore, these spheroids allow the investigation of tumour-stroma interactions and a better reflection of in vivo conditions of cancer cells in their microenvironment. Our method holds potential to contribute to the development of anti-cancer agents and support the search for biomarkers.

The Hu antigens are composed of a family of neuronal-specific, RNA-binding proteins encoded by at least three distinct genes. All three gene products, HuD, HuC/ple21, and Hel-N1, are human homologues of Elav, a Drosophila protein required for neuronal development and maintenance. Although the three proteins are very similar in structure, they are differentiated by alternative splicing of their mRNAs. We report here that the Hu antigens bind avidly to the AU-rich element resident in many mRNAs that regulate cell proliferation. This interaction suggests that the Hu antigens promote neuronal differentiation by suppressing the neuroblast cell cycle. Such a mechanism provides a plausible model for the role of the Hu antigens in tumorigenesis, neuronal differentiation, and paraneoplastic neurologic disorders.

The tumour microenvironment and tumour angiogenesis play a critical role in the development and therapy of many cancers, but in vitro models reflecting these circumstances are rare. In this study, we describe the development of a novel tri-culture model, using non-small cell lung cancer (NSCLC) cell lines (A549 and Colo699) in combination with a fibroblast cell line (SV 80) and two different endothelial cell lines in a hanging drop technology. Endothelial cells aggregated either in small colonies in Colo699 containing microtissues or in tube like structures mainly in the stromal compartment of microtissues containing A549. An up-regulation of hypoxia and vimentin, ASMA and a downregulation of E-cadherin were observed in co- and tri-cultures compared to monocultures. Furthermore, a morphological alteration of A549 tumour cells resembling “signet ring cells” was observed in tri-cultures. The secretion of proangiogenic growth factors like vascular endothelial growth factor (VEGF) was measured in supernatants. Inhibition of these proangiogenic factors by using antiangiogenic drugs (bevacizumab and nindetanib) led to a significant decrease in migration of endothelial cells into microtissues. We demonstrate that our method is a promising tool for the generation of multicellular tumour microtissues and reflects in vivo conditions closer than 2D cell culture.