- Email: [email protected]
SS6-6 Toll-like receptor 2 and deregulated cytokine signaling contribute to gastric inflammation and tumourigenesis
Abstract / Cytokine 52 (2010) 46–47 SS6-5 Histamine reduces susceptibility to NK cells via down-regulation of NKG2D ligand expression on human monocytic leukemia THP-1 cells Y. Nagai, Y. Tanaka, R. Sato, T. Kuroishi, S. Sugawara, Division of Oral Immunology, Department of Oral Biology, Tohoku University, Japan NK group 2, member D (NKG2D) is a key activating receptor expressed on NK and killer T cells, whose interaction with ligands on target cells plays an important role not only in tumorigenesis and but also in infectious immunity. However, the effect of histamine, with its multiple physiological activities, on NKG2D ligands on tumor cells is unclear. Here we showed that human monocytic leukemia THP-1 cells constitutively express MICA and ULBP1 on their surface, and incubation with histamine reduced the expression in a dose and time-dependent manner as assessed by flow cytometry. IFN-c augmented the surface expression of the NKG2D ligands, and this augmentation was significantly attenuated by histamine. The H1R agonist 2-pyridylethylamine and H2R agonist dimaprit down-regulated the expression of NKG2D ligands, and activation of H1R and H2R signaling by A23187 and forskoline, respectively, had the same effect, indicating that the histamine-induced down-regulation of NKG2D ligands is mediated by H1R and H2R. Quantitative RT-PCR showed that mRNA levels of the NKG2D ligands were not significantly changed by histamine. Histamine down-regulated the surface expression of endoplasmic reticulum protein 5, and inhibition of metalloproteinases did not impair this down-regulation, indicating that proteolytic shedding is not involved. Instead, inhibition of protein transport and proteasome abrogated it. Furthermore, histamine treatment significantly reduced susceptibility to NK cell-mediated cytotoxicity. These results suggest that histamine down-regulates NKG2D ligands through the activation of an H1R- and H2R-mediated pathway and consequently reduces susceptibility to NK cells. doi:10.1016/j.cyto.2010.07.195
SS6-6 Toll-like receptor 2 and deregulated cytokine signaling contribute to gastric inflammation and tumourigenesis Catherine L. Kennedy 1, Hazel Tye 1, Meri Najdovska 1, Louise McLeod 1, Luke A.J. O’Neill 2, Paul J. Hertzog 1, Ashley Mansell 1, Brendan J. Jenkins 1, 1 Monash Institute of Medical Research, Clayton, Victoria, Australia, 2 School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland Gastric cancer (GC) is the second most lethal cancer world-wide, and a strong link has been established between gastric colonization by Helicobacter pylori and the development of chronic gastritis and GC. Notably, a significant number (20-25%) of human GC cases develop in the absence of H. pylori, albeit by poorly understood mechanisms. Deregulated activation of cytokine signaling pathways, especially the latent transcription factor signal transducer and activator of transcription (STAT)3, is implicated in various inflammation-associated cancers, including up to 50% of human GC cases. However, the molecular consequences of aberrant STAT3 activation in promoting inflammation and carcinogenesis remain to be fully elucidated. To provide novel insights into such pathological mechanisms in vivo, we have employed a genetic approach based on a mouse strain (gp130Y757F/Y757F) carrying a specific ‘‘knock-in” mutation in the IL-6/IL-11 cytokine family co-receptor gp130 which prevents negative regulation of gp130-dependent signaling. Specifically, IL-11-dependant STAT3 hyper-activation drives the spontaneous development of gastritis and gastric tumors which histologically resemble intestinal-type, metaplastic human GC. We report a novel role for Toll-like receptor (TLR)2, a receptor responsible for
47
recognising diverse bacterial ligands and triggering inflammatory responses, in gastric tumourigenesis in gp130Y757F/Y757F mice. Expression of TLR2 was found to be upregulated in the stomachs of gp130Y757F/Y757F mice and genetic ablation of TLR2, but not other TLRs, in gp130Y757F/Y757F mice alleviated tumour formation. Notably, TLR2 expression was also found to be increased in human gastritis and GC biopsies. The role of TLR2 was further analysed in mice deficient in the TLR2 and TLR4 signaling adaptor protein, Mal. Interestingly, tumourigenesis in gp130Y757F/Y757F:Mal-/- mice was equivalent to their gp130Y757F/Y757Flittermates, echoing recent data indicating that Mal is not essential for TLR2 signaling Collectively, our data indicate a key role for the innate immune system in the development of inflammation-associated GC. doi:10.1016/j.cyto.2010.07.196
SS6-7 The C-terminal decapeptide of prothymosin a induces a TH1-type immune response in vitro and retards tumor growth in vivo Kyriaki Ioannou 1, Pinelopi Samara 1, Nadia Kavrochorianou 2, Christina Bega 1,3, George Thyphronitis 3, Sylva Haralambous 2, Ourania Tsitsilonis 1, 1 Department of Animal and Human Physiology, Faculty of Biology, University of Athens, Athens, Greece, 2 Laboratory of Transgenic Technology, Hellenic Pasteur Institute, Athens, Greece, 3 Department of Biological Applications and Technologies, University of Ioannina, Ioannina, Greece Current cancer immunotherapeutic practice has shown that combinatorial strategies, e.g. vaccination, cellular, humoral and cytokine therapies, elicit adequate and often clinically successful antitumor immune responses. Soluble immunoregulators as cytokines, also termed biologic response modifiers (BRM), are incorporated into active and passive immunotherapy protocols to enhance antitumor host defence mechanisms. For over 30 years, research on the structural and functional properties of thymic peptides has proven that they comprise, perhaps, one of the most effective groups of BRMs. Among them, prothymosin a (proTa) is reported to pleiotropically stimulate immune cells in vitro and in animal models, via generating the appropriate cytokine milieu optimizing cytotoxic lymphocyte activation. We have recently shown that the C-terminal decapeptide proTa(100-109) is the immunologically active segment of proTa, as it enhances the deficient immune responses of cancer patients in vitro to levels equal to those of intact proTa. Moreover, we have shown that proTa(100-109) promotes dendritic cell maturation which consequently prime naive and memory T cell functions by eliciting a TH1-type (IFN-c, GM-CSF, TNF-a) immune response. Herein, we assayed the ability of proTa(100-109) to induce tumor-specific immune responses in a melanoma murine model in vivo. C57BL/6 mice were subcutaneously inoculated with the syngeneic melanoma cells B16.F1 and subsequently treated intraperitoneally with GM-CSF as control, proTa(100-109) or intact proTa, in conjunction with a tumor-specific peptide extract, eluted from B16. We observed that proTPa(100-109) was capable of retarding tumor growth and prolonging overall survival of the animals by 25 days, compared to untreated, B16-inoculated mice. Ex vivo evaluation of murine splenocytes’ cytotoxicity verified the induction of B16-specific and non-specific responses, mediated by activated cytotoxic T and NK/LAK lymphocytes, respectively. Our results indicate that proTa(100-109) in conjunction with tumor-specific epitopes orchestrates anticancer responses and may eventually be used therapeutically for the improvement of clinical results in adoptive immunotherapy of cancer. doi:10.1016/j.cyto.2010.07.197
SS6-6 Toll-like receptor 2 and deregulated cytokine signaling contribute to gastric inflammation and tumourigenesis Catherine L. Kennedy 1, Hazel Tye 1, Meri Najdovska 1, Louise McLeod 1, Luke A.J. O’Neill 2, Paul J. Hertzog 1, Ashley Mansell 1, Brendan J. Jenkins 1, 1 Monash Institute of Medical Research, Clayton, Victoria, Australia, 2 School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland Gastric cancer (GC) is the second most lethal cancer world-wide, and a strong link has been established between gastric colonization by Helicobacter pylori and the development of chronic gastritis and GC. Notably, a significant number (20-25%) of human GC cases develop in the absence of H. pylori, albeit by poorly understood mechanisms. Deregulated activation of cytokine signaling pathways, especially the latent transcription factor signal transducer and activator of transcription (STAT)3, is implicated in various inflammation-associated cancers, including up to 50% of human GC cases. However, the molecular consequences of aberrant STAT3 activation in promoting inflammation and carcinogenesis remain to be fully elucidated. To provide novel insights into such pathological mechanisms in vivo, we have employed a genetic approach based on a mouse strain (gp130Y757F/Y757F) carrying a specific ‘‘knock-in” mutation in the IL-6/IL-11 cytokine family co-receptor gp130 which prevents negative regulation of gp130-dependent signaling. Specifically, IL-11-dependant STAT3 hyper-activation drives the spontaneous development of gastritis and gastric tumors which histologically resemble intestinal-type, metaplastic human GC. We report a novel role for Toll-like receptor (TLR)2, a receptor responsible for
47
recognising diverse bacterial ligands and triggering inflammatory responses, in gastric tumourigenesis in gp130Y757F/Y757F mice. Expression of TLR2 was found to be upregulated in the stomachs of gp130Y757F/Y757F mice and genetic ablation of TLR2, but not other TLRs, in gp130Y757F/Y757F mice alleviated tumour formation. Notably, TLR2 expression was also found to be increased in human gastritis and GC biopsies. The role of TLR2 was further analysed in mice deficient in the TLR2 and TLR4 signaling adaptor protein, Mal. Interestingly, tumourigenesis in gp130Y757F/Y757F:Mal-/- mice was equivalent to their gp130Y757F/Y757Flittermates, echoing recent data indicating that Mal is not essential for TLR2 signaling Collectively, our data indicate a key role for the innate immune system in the development of inflammation-associated GC. doi:10.1016/j.cyto.2010.07.196
SS6-7 The C-terminal decapeptide of prothymosin a induces a TH1-type immune response in vitro and retards tumor growth in vivo Kyriaki Ioannou 1, Pinelopi Samara 1, Nadia Kavrochorianou 2, Christina Bega 1,3, George Thyphronitis 3, Sylva Haralambous 2, Ourania Tsitsilonis 1, 1 Department of Animal and Human Physiology, Faculty of Biology, University of Athens, Athens, Greece, 2 Laboratory of Transgenic Technology, Hellenic Pasteur Institute, Athens, Greece, 3 Department of Biological Applications and Technologies, University of Ioannina, Ioannina, Greece Current cancer immunotherapeutic practice has shown that combinatorial strategies, e.g. vaccination, cellular, humoral and cytokine therapies, elicit adequate and often clinically successful antitumor immune responses. Soluble immunoregulators as cytokines, also termed biologic response modifiers (BRM), are incorporated into active and passive immunotherapy protocols to enhance antitumor host defence mechanisms. For over 30 years, research on the structural and functional properties of thymic peptides has proven that they comprise, perhaps, one of the most effective groups of BRMs. Among them, prothymosin a (proTa) is reported to pleiotropically stimulate immune cells in vitro and in animal models, via generating the appropriate cytokine milieu optimizing cytotoxic lymphocyte activation. We have recently shown that the C-terminal decapeptide proTa(100-109) is the immunologically active segment of proTa, as it enhances the deficient immune responses of cancer patients in vitro to levels equal to those of intact proTa. Moreover, we have shown that proTa(100-109) promotes dendritic cell maturation which consequently prime naive and memory T cell functions by eliciting a TH1-type (IFN-c, GM-CSF, TNF-a) immune response. Herein, we assayed the ability of proTa(100-109) to induce tumor-specific immune responses in a melanoma murine model in vivo. C57BL/6 mice were subcutaneously inoculated with the syngeneic melanoma cells B16.F1 and subsequently treated intraperitoneally with GM-CSF as control, proTa(100-109) or intact proTa, in conjunction with a tumor-specific peptide extract, eluted from B16. We observed that proTPa(100-109) was capable of retarding tumor growth and prolonging overall survival of the animals by 25 days, compared to untreated, B16-inoculated mice. Ex vivo evaluation of murine splenocytes’ cytotoxicity verified the induction of B16-specific and non-specific responses, mediated by activated cytotoxic T and NK/LAK lymphocytes, respectively. Our results indicate that proTa(100-109) in conjunction with tumor-specific epitopes orchestrates anticancer responses and may eventually be used therapeutically for the improvement of clinical results in adoptive immunotherapy of cancer. doi:10.1016/j.cyto.2010.07.197