A phase I pilot trial of MUC1-peptide-pulsed dendritic cells in the treatment of advanced pancreatic cancer.

The objectives of this study were to assess the toxicity and immunological response induced by the intra-dermal (i.d.) administration of MUC1-peptide-pulsed dendritic cells (DCs) in advanced pancreatic cancer patients. Patients with recurrent lesions or metastasis after surgery, and immunohistochemistry positive for MUC1 were treated in cohorts that received 3-6 × 10(6) DCs i.d. for three or four vaccines. Each vaccine was composed of autologus DCs pulsed with MUC1-peptide. Peripheral blood mononuclear cells (PBMCs) that harvested 2 weeks after the second immunization were compared with PBMCs obtained before treatment for immunological response. Serial ELISPOT assays of PBMCs for antitumor reactivity were performed. Three patients received all four vaccines, and four patients received three vaccines. These patients were evaluable for toxicity and immunological monitoring. There were no grade 3 or 4 toxicities associated with the vaccines or major evidence of autoimmunity. Interferon-γ and granzyme B ELISPOT assay reactivity increased significantly in 2 of 7 patients (P < 0.05). The administration of MUC1-peptide-pulsed DCs is non-toxic and capable of inducing immunological response to tumor antigen MUC1 in advanced pancreatic cancer patients. Additional studies are necessary to improve tumor rejection responses.

TLR4 activation is required for IL-17-induced multiple tissue inflammation and wasting in mice.

IL-17 is a recently identified proinflammatory cytokine that plays pivotal roles in several chronic inflammatory disease models. Its expression was also found to be elevated in the serum of patients with chronic diseases. However, whether elevated systemic IL-17 expression can induce pathophysiological tissue inflammation is unknown. In this study, we demonstrated that systemic overexpression of IL-17 using an adenoviral vector could induce multiple tissue inflammation and wasting in mice. We also found that the expression of TLR4 was increased in tissues of IL-17-overexpressing mice. Moreover, TLR4 activation is required for IL-17-induced tissue inflammation and wasting, as evidenced by the absence of aggressive atrophy in gastrocnemius muscle, neutrophil accumulation, and expression of proinflammatory cytokines downstream of TLR4 in multiple tissues of TLR4-deficient mice. Further investigation revealed that TLR4 endogenous ligands high-mobility group box 1 and heat shock protein 22, were systemically upregulated and might be involved in the IL-17-induced TLR4 activation. Our results suggest that IL-17 may induce disease-associated tissue inflammation and wasting through TLR4 signaling. The study indicates a novel interaction between IL-17 and TLR4 activation and may have implications in the pathogenesis and treatment of chronic diseases.

In vivo disruption of TGF-beta signaling by Smad7 in airway epithelium alleviates allergic asthma but aggravates lung carcinogenesis in mouse.

BACKGROUND: TGF-beta has been postulated to play an important role in the maintenance of epithelial homeostasis and the development of epithelium-derived cancers. However, most of previous studies are mainly focused on the function of TGF-beta in immune cells to the development of allergic asthma and how TGF-beta signaling in airway epithelium itself in allergic inflammation is largely unknown. Furthermore, the in vivo TGF-beta function specifically in the airway epithelium during lung cancer development has been largely elusive. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate the in vivo contribution of TGF-beta signaling in lung epithelium to the development of allergic disease and lung cancer, we generated a transgenic mouse model with Smad7, an intracellular inhibitor of TGF-beta signaling, constitutively expressed in mouse airway Clara cells using a mouse CC10 promoter. The mice were subjected to the development of OVA-induced allergic asthma and urethane-induced lung cancer. The Smad7 transgenic animals significantly protected from OVA-induced asthma, with reduced airway inflammation, airway mucus production, extracellular matrix deposition, and production of OVA-specific IgE. Further analysis of cytokine profiles in lung homogenates revealed that the Th2 cytokines including IL-4, IL-5 and IL-13, as well as other cytokines including IL-17, IL-1, IL-6, IP10, G-CSF, and GM-CSF were significantly reduced in the transgenic mice upon OVA induction. In contrast, the Smad7 transgenic animals had an increased incidence of lung carcinogenesis when subjected to urethane treatment. CONCLUSION/SIGNIFICANCE: These studies, therefore, demonstrate for the first time the in vivo function of TGF-beta signaling specifically in airway epithelium during the development of allergic asthma and lung cancer.

Lecithin promotes adipocyte differentiation and hepatic lipid accumulation.

Lecithin is an essential biological component and widely used as a nutritional supplement for protecting cells from oxidation, increase fat burning and preventing cardiovascular disease. Lecithin contains fatty acids identified as the peroxisome proliferator-activated receptor (PPAR) agonists. However, the role of lecithin in adipogenesis and lipogenesis remains elusive. 3T3-L1 cells and mouse primary preadipocytes were used to characterize the properties of lecithin related to adipogenesis and lipogenesis. We found that lecithin promoted adipocyte differentiation and differentiation-specific gene expression, and increased triglycerides and free fatty acid levels in the adipocytes. These effects are independent of the clonal expansion of 3T3-L1 cells and the upstream PPARgamma regulator, CCAAT-enhancer-binding protein beta. Furthermore, lecithin induced lipid accumulation in human hepatoma HepG2 cells. Our data suggest that lecithin is involved in adipogenesis, lipogenesis and hepatic lipid accumulation and it is implicated in obesity and hepatic steatosis.

Induction of CD4+CD25+Foxp3+ regulatory T cell response by glatiramer acetate in type 1 diabetes.

Glatiramer acetate (GA) is an immunomodulatory peptide drug used to treat multiple sclerosis. Its treatment effect has been expanded to other autoimmune conditions such as uveoretinitis, inflammatory bowel disease, graft rejection and hepatic fibrosis. Here, we report that GA was effective in altering the clinical course of diabetes in cyclophosphamide (CY)-potentiated non-obese diabetic (CY-NOD) mice. Treatment with GA significantly reduced the diabetic rate in the mice and ameliorated insulitis, which coincided with increased CD4+CD25+Foxp3+ T cell response in treated mice. GA treatment led to increased expression of transcription factor Foxp3 and elevated production of interleukin-4 (IL-4) both in vivo and in vitro. It was evident that the effect of GA on up-regulation of Foxp3 was mediated partially through IL-4. IL-4 was found to maintain Foxp3 expression and regulatory function of CD4+CD25+ regulatory T cells (Tregs). This study provides new evidence that GA has treatment potential for type 1 diabetes through the induction of Tregs and that increased IL-4 production is partially responsible for the enhanced Treg's function in GA treatment.

Differentiation of embryonic stem cells towards pancreatic progenitor cells and their transplantation into streptozotocin-induced diabetic mice.

Type I diabetes is characterized by the deficiency of endocrine beta cells in the pancreatic islets of Langerhans and transplantation of islet cells can be an effective therapeutic approach. Embryonic stem cells can be differentiated into any cell type, and therefore represent an unlimited source of islet cells for the transplantation and treatment for type I diabetes. We have adopted an easy and reproducible in vitro differentiation system with a reduced serum concentration plus nicotinamide to generate early pancreatic progenitor cells from embryonic stem cells. Gene expression analysis indicated that the differentiated cells expressed not only endoderm markers such as GATA-4, HNF-3beta, but also early markers of pancreatic development including key transcription factors PDX-1 and IAPP. Some pancreatic specific markers, such as insulin I, insulin II, Glu-2 and glucagon, were also expressed to some extent at the mRNA level. Differentiated ES cells showed low level immunoreactivity for insulin. However, transplantation of these early pancreatic progenitor clusters into STZ-induced diabetic mice failed to reverse the hyperglycemic state of the disease as reported previously. The results suggest that culture manipulation can direct ES cells to differentiate into early pancreatic progenitor cells committing to pancreatic islet cell fate, but these cells cannot function normally to reduce blood glucose of diabetic mice at this stage.

SOCS1 silencing can break high-dose dendritic cell immunotherapy-induced immune tolerance.

Dendritic cells (DCs) play a pivotal role in T cell-mediated immunity and have been shown to induce strong anti-tumor immune responses. As of yet, only a limited number of objective tumor regressions have been observed in clinical studies using a DC vaccine. Suppressor of cytokine signaling-1 (SOCS1) is a key negative regulator of the JAK/STAT signal pathway and plays an essential role in suppressing systemic autoimmunity that is mediated by DCs. The aim of this study was to investigate whether SOCS1-silenced DCs can break the vaccine-induced immune tolerance stimulated by high-dose DC, thereby enhancing anti-tumor activity. In the mouse melanoma model, we found that a 2x106 TRP2-pulsed DC vaccine was able to induce immune tolerance, while a 2x106 SOCS1-silenced DC/TRP2 vaccine prevented immune tolerance. Further experiments revealed that activation-induced T cell death (AICD) through the Fas/Fas-L pathway may play a crucial role in immune tolerance induced by 2x106 TRP2-pulsed DC. SOCS1-silencing in DCs could prevent immune tolerance by inhibiting Fas and Fas-L expression, induced by an increase in IL-12p70 and IL-6 production. In addition, in 2x106 SOCS1-silenced DC/TRP2 immunized mice, higher levels of IL-12p70 and IFN-γ and lower IL-17 production may inhibit tumor angiogenesis and therefore assist in breaking immune tolerance. In conclusion, high-doses of DCs can inhibit the vaccine-induced AICD of T cells and cytokine regulation in tumor angiogenesis. These results indicate that SOCS1-silenced DC vaccines may greatly enhance anti-tumor activity by breaking self-tolerance.