Reprogramming tumor-infiltrating dendritic cells for CD103+ CD8+ mucosal T-cell differentiation and breast cancer rejection

Ligand-receptor dissociated expression explains high TSLP without prognostic impact in human primary head and neck squamous cell carcinoma

Thymic stromal lymphopoietin (TSLP) is an interleukin (IL)-7-like cytokine expressed by epithelial cells during allergic inflammation, and activating dendritic cells (DC). Its expression and functional role in cancer remain controversial. We conducted retrospective (n = 89), and prospective studies including patients with untreated primary head and neck squamous cell carcinoma (HNSCC). We found that TSLP was overexpressed by HNSCC tumor cells, and associated with a highly differentiated status. However, no significant difference in overall and recurrence-free survival was found between patients bearing a tumor with high and low TSLP levels, respectively. Surprisingly, there was no significant association between the levels of TSLP expression, and the number of tumor-infiltrating mature DCLAMP(+) DC. In order to explain the apparent lack of TSLP-induced DC activation, we performed phenotypic and functional experiments on freshly resected tumors. Tumor-infiltrating immune cells, including DC, did not express the TSLP receptor heterodimer (TSLPR chain, IL-7Ralpha chain). Furthermore, freshly sorted blood CD11c(+) DC from healthy donors cultured with tumor-conditioned supernatant exhibited an activated profile, but this was not affected by an anti-TSLP blocking antibody, suggesting a DC activation pathway independent of tumor-derived TSLP. Overall, our results demonstrate that TSLP is overexpressed in HNSCC but its function is hampered by the lack of TSLPR-expressing cells in the tumor microenvironment. Such a dissociated ligand-receptor expression may impact intercellular communication in other immune activation pathways, and tumor types.

No evidence for TSLP pathway activity in human breast cancer

Thymic stromal lymphopoietin (TSLP) is an epithelial cell-derived cytokine that primes dendritic cells for Th2 induction. It has been implicated in different types of allergic diseases. Recent work suggested that TSLP could play an important role in the tumor microenvironment and influence tumor progression, in particular in breast cancer. In this study we systematically assessed the production of TSLP at the mRNA and protein levels in several human breast cancer cell lines, large-scale public transcriptomics data sets, and primary human breast tumors. We found that TSLP production was marginal, and concerned less than 10% of the tumors, with very low mRNA and protein levels. In most cases TSLP was undetectable and found to be expressed at lower levels in breast cancer as compared to normal breast tissue. Last, we could not detect any functional TSLP receptor (TSLPR) expression neither on hematopoietic cells nor on stromal cells within the primary tumor microenvironment. We conclude that TSLP-TSLPR pathway activity is not significantly detected within human breast cancer. Taken together, these observations do not support TSLP targeting in breast cancer.

TSLP production by dendritic cells is modulated by IL-1β and components of the endoplasmic reticulum stress response

Thymic stromal lymphopoietin (TSLP) produced by epithelial cells acts on dendritic cells (DCs) to drive differentiation of T_H2‐cells, and is therefore important in allergic disease pathogenesis. However, DCs themselves make significant amounts of TSLP in response to microbial products, but little is known about the key downstream signals that induce and modulate this TSLP secretion from human DCs. We show that human monocyte derived DC (mDC) secretion of TSLP in response to Candida albicans and β‐glucans requires dectin‐1, Syk, NF‐κB, and p38 MAPK signaling. In addition, TSLP production by mDCs is greatly enhanced by IL‐1β, but not TNF‐α, in contrast to epithelial cells. Furthermore, TSLP secretion is significantly increased by signals emanating from the endoplasmic reticulum (ER) stress response, specifically the unfolded protein response sensors, inositol‐requiring transmembrane kinase/endonuclease 1 and protein kinase R‐like ER kinase, which are activated by dectin‐1 stimulation. Thus, TSLP production by mDCs requires the integration of signals from dectin‐1, the IL‐1 receptor, and ER stress signaling pathways. Autocrine TSLP production is likely to play a role in mDC‐controlled immune responses at sites removed from epithelial cell production of the cytokine, such as lymphoid tissue.

JAK/STAT3 signaling pathway mediates endothelial-like differentiation of immature dendritic cells

Endothelial-like differentiation (ELD) of dendritic cells (DCs) is a poorly understood phenomenon. The present study evaluated the effect on the ELD of DCs by using human esophageal squamous cell carcinoma (ESCC) cells with high or poor differentiation. The results demonstrated that KYSE450 (highly differentiated) and KYSE70 (poorly differentiated) cell supernatants induce the differentiation of immature DCs (iDCs), derived from healthy adult volunteers, away from the DC pathway and towards an endothelial cell (EC) fate. This effect was strongest in the cells treated with the KYSE70 supernatant. During the ELD of iDCs, sustained activation of JAK (janus tyrosine kinase)/STAT3 (signal transducer and activator of transcription 3) signaling was detected. Incubation of iDCs with the JAK inhibitor, AG490 blocked JAK/STAT3 phosphorylation and iDC differentiation. These results suggested that the JAK/STAT3 signaling pathway mediates ELD of iDCs. Furthermore, the poorly differentiated ESCC cells may have a greater effect on the ELD of iDCs than highly differentiated ESCC cells.

A novel kefir product (PFT) activates dendritic cells to induce CD4+T and CD8+T cell responses in vitro

Lactobacilli have been widely studied for their probiotic effects and have been reported to function as antiviral and anticancer agents. However, the underlying mechanisms via immune modulation are poorly understood. PFT is a freeze dried compound of Lactobacillus kefiri P-IF with a unique composition and functionality. In this study, we examined the potential stimulatory effects of two concentrations (50 µg and 100 µg/mL) of PFT on human monocyte-derived dendritic cell (DC) function in vitro. Results showed that PFT upregulated the expression of DC surface co-stimulatory and maturation markers CD80, CD86, and HLADR in a concentration dependent manner. PFT at 100 µg/mL markedly increased the secretion of IL-6, IL-10, TNF-α, and IL-1β by DCs. This concentration of PFT also stimulated the production of antiviral cytokines, IFN-α and IFN-λ(IL29) in DCs. Additionally, PFT at 100 µg/mL activated moDCs prime CD4(+)T cells and significantly increased the levels of IL-10, IFN-γ, and TNF-α by 1.7, four, three-fold, respectively. Furthermore PFT-stimulated DCs were also effective in enhancing the cytotoxic potential of CD8(+)T cells via the induction of Granzyme-B and upregulation of CD107a, and CD103 expression, a marker of resident/regulatory CD8(+)T cells. These data suggest that PFT functions as a natural adjuvant for DC activation and thus may be used in DC-based vaccine strategies against viral infections and cancer.

Myeloid Cells as Targets for Therapy in Solid Tumors

It is well established that cancer development ensues based on reciprocal interactions between genomically altered neoplastic cells and diverse populations of recruited "host" cells co-opted to support malignant progression. Among the host cells recruited into tumor microenvironments, several subtypes of myeloid cells, including macrophages, monocytes, dendritic cells, and granulocytes contribute to tumor development by providing tumor-promoting factors as well as a spectrum of molecules that suppress cytotoxic activities of T lymphocytes. Based on compelling preclinical data revealing that inhibition of critical myeloid-based programs leads to tumor suppression, novel immune-based therapies and approaches are now entering the clinic for evaluation. This review discusses mechanisms underlying protumorigenic programming of myeloid cells and discusses how targeting of these has potential to attenuate solid tumor progression via the induction and of mobilization CD8 cytotoxic T cell immunity.

Opposing Roles of Dectin-1 Expressed on Human Plasmacytoid Dendritic Cells and Myeloid Dendritic Cells in Th2 Polarization

Dendritic cells (DCs) can induce and control host immune responses. DC subset-dependent functional specialties and their ability to display functional plasticity, which is mainly driven by signals via pattern recognition receptors, identify DCs as immune orchestrators. A pattern recognition receptor, Dectin-1, is expressed on myeloid DCs and known to play important roles in Th17 induction and activation during fungal and certain bacterial infections. In this study, we first demonstrate that human plasmacytoid DCs express Dectin-1 in both mRNA and protein levels. More interestingly, Dectin-1-activated plasmacytoid DCs promote Th2-type T cell responses, whereas Dectin-1-activated myeloid DCs decrease Th2-type T cell responses. Such contrasting outcomes of Th2-type T cell responses by the two DC subsets are mainly due to their distinct abilities to control surface OX40L expression in response to β-glucan. This study provides new insights for the regulation of host immune responses by Dectin-1 expressed on DCs.

Rheumatoid arthritis vaccine therapies: perspectives and lessons from therapeutic ligand epitope antigen presentation system vaccines for models of rheumatoid arthritis

The current status of therapeutic vaccines for autoimmune diseases is reviewed with rheumatoid arthritis as the focus. Therapeutic vaccines for autoimmune diseases must regulate or subdue responses to common self-antigens. Ideally, such a vaccine would initiate an antigen-specific modulation of the T-cell immune response that drives the inflammatory disease. Appropriate animal models and types of T helper cells and signature cytokine responses that drive autoimmune disease are also discussed. Interpretation of these animal models must be done cautiously because the means of initiation, autoantigens, and even the signature cytokine and T helper cell (Th1 or Th17) responses that are involved in the disease may differ significantly from those in humans. We describe ligand epitope antigen presentation system vaccine modulation of T-cell autoimmune responses as a strategy for the design of therapeutic vaccines for rheumatoid arthritis, which may also be effective in other autoimmune conditions.

Anti-CD40-induced inflammatory E-cadherin+ dendritic cells enhance T cell responses and antitumour immunity in murine Lewis lung carcinoma

Background

Agonistic CD40 antibodies have been demonstrated to activate antigen-presenting cells (APCs) and enhance antitumour T cell responses, thereby providing a new therapeutic option in cancer immunotherapy. In agonistic CD40 antibody-mediated inflammatory responses, a novel subset of E-cadherin + dendritic cells (DCs) has been identified, and little is known about the role of these DCs in tumour immunity. This study investigated the effect of anti-CD40-mediated inflammatory E-cadherin + DCs in murine Lewis lung carcinoma (LLC).

Methods

The phenotype and characteristics of anti-CD40-mediated inflammatory E-cadherin + DCs isolated from the anti-CD40 model were assessed in vitro. The antitumour activity of E-cadherin + DCs were evaluated in vivo by promoting the differentiation of effector CD4+ T cells, CEA-specific CD8+ T cells and CD103+ CD8+ T cells and assessing their resistance to tumour challenge, including variations in tumour volume and survival curves.

Results

Here, we demonstrated that anti-CD40-mediated E-cadherin + inflammatory DCs accumulate in the lungs of Rag1 KO mice and were able to stimulate naïve CD4+ T cells to induce Th1 and Th17 cell differentiation and polarisation and to inhibit regulatory T cell and Th2 responses. Importantly, with the adoptive transfer of E-cadherin + DCs into the Lewis lung cancer model, the inflammatory DCs increased the Th1 and Th17 cell responses and reduced the Treg cell and Th2 responses. Interestingly, following the injection of inflammatory E-cadherin + DCs, the CD103+ CD8+ T cell and CEA-specific CD8+ T cell responses increased and exhibited potent antitumour immunity.

Conclusions

These findings indicate that anti-CD40-induced E-cadherin + DCs enhance T cell responses and antitumour activity in non-small cell lung cancer (NSCLC)-bearing mice and may be used to enhance the efficacy of DC-based peptide vaccines against NSCLC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0126-9) contains supplementary material, which is available to authorized users.

Dynamic analysis of tumor-associated immune cells in DEN-induced rat hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive disease with poor prognosis and limited methods to predict patient survival. Immune cells infiltrating tumors are known to impact tumor progression. Here, we analyzed the phenotype and function of dendritic cells (DCs), and the frequency of IL-10-producing regulatory B cells (Breg) and Foxp3(+) regulatory T cells (Treg) in different stages of N-nitrosodiethylamine (DEN)-induced rat HCC in order to understand their roles in this disease. 4weeks following DEN treatment, no significant differences in CD80 and CD86 expression were found on DCs from HCC rats and normal rats but 12 and 16weeks following DEN treatment, the expression of CD80, CD86 and MHCII on DCs of HCC rats was significantly decreased. We also found that the frequency of IL-10-producing Breg and CD4(+)CD25(+)Foxp3(+) Treg in HCC rats was obviously increased during all of these three stages. In addition, the bone-marrow derived DCs (BMDCs) from HCC rats displayed lower ability in activating T cells and an increase in IL-10 secretion. No differences in IL-12 level and endocytosis ability were found on BMDCs from HCC rats and normal rats. Our results suggest that the dysfunction of DCs and the increase of IL-10-producing Breg and Foxp3(+) Treg might play important roles in HCC progression.