BTK operates a phospho-tyrosine switch to regulate NLRP3 inflammasome activity.

Activity of the NLRP3 inflammasome, a critical mediator of inflammation, is controlled by accessory proteins, posttranslational modifications, cellular localization, and oligomerization. How these factors relate is unclear. We show that a well-established drug target, Bruton's tyrosine kinase (BTK), affects several levels of NLRP3 regulation. BTK directly interacts with NLRP3 in immune cells and phosphorylates four conserved tyrosine residues upon inflammasome activation, in vitro and in vivo. Furthermore, BTK promotes NLRP3 relocalization, oligomerization, ASC polymerization, and full inflammasome assembly, probably by charge neutralization, upon modification of a polybasic linker known to direct NLRP3 Golgi association and inflammasome nucleation. As NLRP3 tyrosine modification by BTK also positively regulates IL-1ß release, we propose BTK as a multifunctional positive regulator of NLRP3 regulation and BTK phosphorylation of NLRP3 as a novel and therapeutically tractable step in the control of inflammation.

Innate Immune Stimulation in Cancer Therapy.

The innate immune system has evolved as a first line of defense against invading pathogens and acts via classes of germline-encoded receptor systems to respond with proinflammatory cytokines. Innate immune cells, predominantly cells of the myeloid compartment, are capable of providing a potent basis for boosting adaptive immunity in malignant diseases. The authors review their current understanding of the molecular mechanisms whereby innate pattern recognition receptors participate in immunosurveillance of cancer cells. They discuss how innate effector mechanisms are currently being targeted pharmacologically and how improved understanding of the biology of these pathways is leading to novel immunotherapies of cancer.

Biologic meshes and synthetic meshes in cancer patients: a double-edged sword: differences in production of IL-6 and IL-12 caused by acellular dermal matrices in human immune cells.

PURPOSE: In 2005, Breuing et al. first described the use of acellular dermal matrices (ADMs) in breast cancer patients. ADMs are assumed to be safe to use in an oncologic setting, but data from controlled studies are still needed. Here, we investigate the effects of ADMs on the production of interleukin (IL)-6 and IL-12, key regulators of immune suppression and activation. METHODS: Strattice (ST), CollaMend (CM), and Biodesign (BD) biologic meshes and TiLoop, a synthetic mesh (TL), were used in this study. We isolated myeloid dendritic cells (MDCs), untouched plasmacytoid dendritic cells (pDCs), naïve B cells, and CD8+ T cells and co-cultured these cells with either the biologic meshes or TL. As positive controls, we used CpG ODN 2216 or lipopolysaccharide (LPS). The cytokine concentrations of IL-12p70 and IL-6 were determined after 7 days using sandwich ELISA sets. RESULTS: There were highly significant differences between the ADMs and TL in terms of their ability to stimulate immunologic responses. IL-6 expression was significantly increased in B cells (p = 0.0006131) and T cells (p = 0.00418) when comparing TL and ADMs. We also identified significant differences in IL-12 production by B cells (p = 0.0166) and T cells (p = 0.003636) when comparing TL and ADMs. CONCLUSIONS: Despite the assumed lack of an immunological response to ADMs, in our experimental study, human immune cells reacted with significantly different cytokine profiles. These findings may have implications for the potential activation or suppression of effector cells in cancer patients and could explain some of the post clinical post surgical signs of ADMS like skin rush and seroma.

A Bifunctional Approach of Immunostimulation and uPAR Inhibition Shows Potent Antitumor Activity in Melanoma.

Significant advancements of mutation-based targeted therapy and immune checkpoint blockade have been achieved in melanoma. Nevertheless, acquired resistance and nonresponders to therapy require different strategies. An innovative approach is presented here that is based on the combination of innate immune system activation and simultaneous targeting of the oncogene urokinase-type plasminogen activator receptor (uPAR). We generated two triphosphate-conjugated siRNAs targeting uPAR (ppp-uPAR) by in vitro transcription. Specific uPAR knockdown and simultaneous activation of the retinoic acid-inducible gene 1 (RIG-I) was shown in different human melanoma cells, fibroblasts, and melanocytes. The compounds induced massive apoptosis in melanoma cells, whereas fibroblasts and melanocytes were less sensitive. The effects were less pronounced when the IFN receptor was blocked. Treatment with ppp-uPAR led to accumulation of p53 and induction of RIG-I-dependent proapoptotic signaling. The apoptotic effects induced by ppp-uPAR were maintained in melanoma cell lines that had acquired double resistance to B-RAF and MEK/extracellular signal-regulated kinase inhibition. Systemic intraperitoneal application of ppp-uPAR in nude mice significantly reduced growth of human melanoma xenografts and elicited a systemic innate immune response with increased serum cytokine levels. Our data suggest that ppp-uPAR represents a therapeutically attractive compound that may help overcome the strong therapy resistance of melanoma.

Impact of a New Fusion Receptor on PD-1-Mediated Immunosuppression in Adoptive T Cell Therapy.

BACKGROUND: Adoptive T cell transfer (ACT) is currently under investigation for the treatment of metastatic cancer. Recent evidence suggests that the coinhibitory PD-1-PD-L1 axis plays a major role in ACT failure. We hypothesized that a new fusion receptor reverting PD-1-mediated inhibition into CD28 costimulation may break peripheral tolerance. METHODS: Different PD-1-CD28 fusion receptor constructs were created and retrovirally transduced into primary T cell receptor transgenic murine CD8(+) T cells specific for ovalbumin (OT-1). Cytokine release, proliferation, cytotoxicity, and tumor recognition were analyzed in vitro. Antitumor efficacy and mode of action were investigated in mice bearing subcutaneous tumors induced with the pancreatic carcinoma cell line Panc02 expressing the model antigen ovalbumin (Panc-OVA). For antitumoral efficacy, six to eight mice per group were used. All statistical tests are two-sided. RESULTS: Transduction of the PD-1-CD28 receptor constructs mediated enhanced cytokine release, T cell proliferation, and T cell-induced lysis of target tumor cells. The PD-1-CD28 receptor function was dependent on two of the CD28-signaling motifs and IFN-γ release. Treatment of mice with established Panc-OVA tumors with fusion receptor-transduced OT-1 T cells mediated complete tumor regression. Mice rejecting the tumor were protected upon subsequent rechallenge with either ovalbumin-positive or -negative tumors, indicative of a memory response and epitope spreading in nine of 11 mice vs none of the six naïve mice (P < .001). Treatment efficacy was associated with accumulation of IFN-γ-producing T cells and an increased ratio of CD8(+) T cells to immunosuppressive myeloid-derived suppressor cells in the tumors. CONCLUSIONS: Transduction of T cells with this new PD-1-CD28 receptor has the potential of breaking the PD-1-PD-L1-immunosuppressive axis in ACT.

Interleukin-22 is frequently expressed in small- and large-cell lung cancer and promotes growth in chemotherapy-resistant cancer cells.

INTRODUCTION: In lung cancer, interleukin-22 (IL-22) expression within primary tissue has been demonstrated, but the frequency and the functional consequence of IL-22 signaling have not been addressed. This study aims at analyzing the cellular effects of IL-22 on lung carcinoma cell lines and the prognostic impact of IL-22 tissue expression in lung cancer patients. METHODS: Biological effects of IL-22 signaling were investigated in seven lung cancer cell lines by Western blot, flow cytometry, real-time polymerase chain reaction, and proliferation assays. Tumor tissue specimens of two cohorts with a total of 2300 lung cancer patients were tested for IL-22 expression by immunohistochemistry. IL-22 serum concentrations were analyzed in 103 additional patients by enzyme-linked immunosorbent assay. RESULTS: We found the IL-22 receptor 1 (IL-22-R1) to be expressed in six of seven lung cancer cell lines. However IL-22 signaling was functional in only four cell lines, where IL-22 induced signal transducer activator of transcription 3 phosphorylation and increased cell proliferation. Furthermore, IL-22 induced the expression of antiapoptotic B-cell lymphoma 2, but did not rescue tumor cells from carboplatin-induced apoptosis. Cisplatin-resistant cell lines showed a significant up-regulation of IL-22-R1 along with a stronger proliferative response to IL-22 stimulation. IL-22 was preferentially expressed in small- and large-cell lung carcinoma (58% and 46% of cases, respectively). However, no correlation between IL-22 expression by immunohistochemistry and prognosis was observed. CONCLUSION: IL-22 is frequently expressed in lung cancer tissue. Enhanced IL-22-R1 expression and signaling in chemotherapy-refractory cell lines are indicative of a protumorigenic function of IL-22 and may contribute to a more aggressive phenotype.