Increased frequency and suppressive activity of CD127(low/-) regulatory T cells in the peripheral circulation of patients with head and neck squamous cell carcinoma are associated with advanced stage and nodal involvement

What happens to regulatory T cells in multiple myeloma

Abnormal tumor microenvironment and immune escape in multiple myeloma (MM) are associated with regulatory T cells (Tregs), which play an important role in maintaining self-tolerance and regulating the overall immune response to infection or tumor cells. In patients with MM, there are abnormalities in the number, function and distribution of Tregs, and these abnormalities may be related to the disease stage, risk grade and prognosis of patients. During the treatment, Tregs have different responses to various treatment regiments, thus affecting the therapeutic effect of MM. It is also possible to predict the therapeutic response by observing the changes of Tregs. In addition to the above, we reviewed the application of Tregs in the treatment of MM. In conclusion, there is still much room for research on the mechanism and application of Tregs in MM.

[Tislelizumab monotherapy for the treatment of recurrent/metastatic head and neck squamous cell carcinoma]

Objective:The aim of this retrospective study is to evaluate the safety and efficacy of tislelizumab in patients with recurrent/metastatic head and neck squamous cell carcinoma. Methods:Six patients with recurrent/metastatic head and neck squamous cell carcinoma who received tislelizumab monotherapy in our hospital from 2018 to 2020 were retrospectively analyzed. The information of sex, age, TNM stage, efficacy, and adverse reactions were collected. All patients were recruited from the RATIONALE 102 study. The primary end point was the objective response rate, and other end points included progression-free survival and overall survival. We performed tumor immune-related gene sequencing and transcriptome sequencing analysis on the tumor tissues of the patient, and used bioinformatics methods to enrich immune cells and analyze signaling pathways. All analyses were performed using R 4.1. 0 software, SPSS Statistics 24.0 software and GraphPad Prism 8. Results:As of May 31, 2020, the median follow-up time was 26.35 months. The objective response rate with tislelizumab was 50.0%, the median progression-free survival was 6.44 months, and the estimated median survival was 20.07 months. The incidence of grade 3 or higher adverse reactions was 66.7%, including hyponatremia, hypokalemia, hypercalcemia, etc. The expression of macrophage, Treg and neutrophil-related genes are higher in immune-sensitive patients, and the signaling pathways of the intestinal immune network for IgA production, graft versus host disease and autoimmune thyroid disease are significantly activated. Conclusion:Tislelizumab was found to be controllable and tolerable in patients with recurrent/metastatic head and neck squamous cell carcinoma. The response to tislelizumab is related to immune cell infiltration and activation of immune-related signaling pathways.

High density of CD8 T cell and immune imbalance of T lymphocytes subsets are associated with proliferative verrucous leukoplakia

Oral leukoplakia (OL) and proliferative verrucous leukoplakia (PVL) are oral potentially malignant disorders (OPMDs) that microscopically show no or varying degrees of dysplasia. Even sharing clinical and microscopic aspects, PVL shows a more aggressive clinical behaviour, with a malignant transformation rate greater than 40%. Inflammatory infiltrate associated with dysplastic lesions may favour malignant transformation of OPMDs. This study aimed to evaluate the density of T cells and cytokines in dysplastic lesions from OL and PVL patients. Additionally, we evaluated whether soluble products produced in vitro by dysplastic keratinocytes are capable of modulating apoptosis rates and Th phenotype (Th1, Th2, Th17 and Treg) of peripheral blood mononuclear cells. The density of CD3, CD4 and CD8 T cells was assessed by immunohistochemistry. Cytokines and chemokines profile from frozen tissue samples were analysed using the LUMINEX system. Apoptosis rates and Th phenotype modulation were evaluated by flow cytometry. Our results showed an increase in the number of CD8 T cell in the subepithelial region from PVL dysplastic lesions in relation to OL samples. PVL showed increased levels of IL-5 and a decrease in IL-1β and IFN-γ levels compared to OL. Soluble products of PVL and oral carcinoma cell cultures were able to reduce apoptosis rate and promote an imbalance of Th1/Th2 and Th17/Treg. The high-subepithelial density of CD8 T cells and immune imbalance of T lymphocytes subsets probably play an important role in the pathogenesis of PVL and may explain its more aggressive behaviour in relation to OL.

Regulatory and effector T cell subsets in tumor-draining lymph nodes of patients with squamous cell carcinoma of head and neck

Background

A crucial role for the immune system has been proposed in the establishment and progression of head and neck squamous cell carcinoma (HNSCC). In this study, we investigated the cytokine and regulatory profiles of T cells in tumor draining lymph nodes (TDLNs) of patients with HNSCC.

Results

The frequencies of CD4+TNF-α+ and CD4+TNF-αhi negatively were associated with poor prognostic factors such as LN involvement (P = 0.015 and P = 0.019, respectively), stage of the disease (P = 0.032 and P = 0.010, respectively) and tumor size (P = 0.026 and P = 0.032, respectively). Frequencies of CD8+IFN-γ+ and CD8+IFN-γ+ TNF-α+ T cells showed negative relationship with tumor grade (P = 0.035 and P = 0.043, respectively). While, the frequencies of CD4+IL-4+, CD8+IL-10+, CD8+IL-4+T cells were higher in advanced stages of the disease (P = 0.042, P = 0.041 and P = 0.030, respectively) and CD4+IFN-γ+TNF-α−, CD8+IL-4+ and CD8+IFN-γ+TNF-α− T cells were higher in patients with larger tumor size (P = 0.026 and P = 0.032, respectively). Negative associations were found between the frequencies of CD4+CD25+Foxp3+ and CD4+CD25+Foxp3+CD127low/− Treg cells and cancer stage (P = 0.015 and P = 0.059).

Conclusion

This study shed more lights on the changes in immune profile of T cells in TDLNs of HNSCC. Larger tumor size and/or LN involvement were associated with lower frequencies of CD4+TNF-α+, CD8+IFN-γ+ and CD8+IFN-γ+TNF-α+ but higher frequency of CD4+IL-4+ T cells. Moreover, Foxp3+Tregs correlated with good prognostic indicators.

Overview on Molecular Biomarkers for Laryngeal Cancer: Looking for New Answers to an Old Problem

Laryngeal squamous cell cancer (LSCC) accounts for almost 25-30% of all head and neck squamous cell cancers and is clustered according to the affected districts, as this determines distinct tendency to recur and metastasize. A major role for numerous genetic alterations in driving the onset and progression of this neoplasm is emerging. However, major efforts are still required for the identification of molecular markers useful for both early diagnosis and prognostic definition of LSCC that is still characterized by significant morbidity and mortality. Non-coding RNAs appear the most promising as they circulate in all the biological fluids allowing liquid biopsy determination, as well as due to their quick and characteristic modulation useful for non-invasive detection and monitoring of cancer. Other critical aspects are related to recent progress in circulating tumor cells and DNA detection, in metastatic status and chemo-refractoriness prediction, and in the functional interaction of LSCC with chronic inflammation and innate immunity. We review all these aspects taking into account the progress of the technologies in the field of next generation sequencing.

Prognostic Relevance of CD4+, CD8+ and FOXP3+ TILs in Oral Squamous Cell Carcinoma and Correlations with PD-L1 and Cancer Stem Cell Markers

This study investigates the relevance of tumor-infiltrating lymphocytes (TILs) in oral squamous cell carcinoma (OSCC). Immunohistochemical analysis of stromal/tumoral CD4⁺, CD8⁺ and FOXP3⁺ TILs is performed in 125 OSCC patients. Potential relationships with the expression of tumoral PD-L1 and cancer stem cell (CSC) markers (NANOG, SOX2, OCT4, Nestin and Podoplanin (PDPN)) are assessed. CD4⁺ and CD8⁺ TILs are significantly associated with smoking and alcohol habits. CD4⁺ and CD8⁺ TILs show an inverse relationship with NANOG and SOX2 expression, and FOXP3⁺ TILs is significantly correlated with Nestin and PDPN expression. High infiltration of CD4⁺ and CD8⁺ TILs and a high tumoral CD8⁺/FOXP3⁺ ratio are significantly associated with tumors harboring positive PD-L1 expression. Infiltration of stromal/tumoral FOXP3⁺ TILs and a low stromal CD8⁺/FOXP3⁺ ratio are significantly associated with better disease-specific survival. Multivariate analysis reveals that the stromal CD8⁺/FOXP3⁺ TILs ratio is a significant independent prognostic factor. Regarding OSCC patient survival, the CD8⁺/FOXP3⁺ TILs ratio is an independent prognostic factor. TILs may act as biomarkers and potential therapeutic targets for OSCC.

Influence of Immune Microenvironment on Diagnosis and Prognosis of Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is an immunosuppressive malignancy accompanied by noted alterations in various immune cells and cytokines. Recognition of the immune system's role in contributing to cancer development is an important advancement in our original understanding of carcinoma. We obtained HNSCC gene expression and clinical data from The Cancer Genome Atlas (TCGA) database. We assessed the relative proportion of 22 Infiltrating immune cell types in both HNSCC and adjacent non-cancer tissues using Cell-type Identification By Estimating Relative Subsets Of RNA Transcripts (CIBERSORT) method, identifying the influence of the immune cells content in tumor staging and survival prediction. We further predicted the tumor purity, and the presence of infiltrating stromal/immune cells in HNSCC tissues using Estimation of STromal and Immune cells in Malignant Tumor tissues using Expression data (ESTIMATE) algorithm, identifying its potential correlation with patient survival. Stromal and immune score-associated differentially expressed genes (DEGs) were subsequently verified and their roles in immune response were displayed by functional enrichment analysis and protein-protein interaction (PPI) network. Our research demonstrated the underlying association between the immune microenvironment and HNSCC, and the results were intended to serve as valuable terms for HNSCC diagnosis, prognosis, and targeted immune therapy.

The Tumor Microenvironment and Immunotherapy of Oropharyngeal Squamous Cell Carcinoma

Oropharyngeal squamous cell carcinoma (OPSCC) develops as a consequence of several mutations in the tumor suppressor pathways or after a progressive infection with high risk human papillomavirus (HPV). The dismal side effects of the current standard of care and the clear involvement of the immune system has led to a surge in clinical trials that aim to reinforce the tumor-specific immune response as a new treatment option. In this review, we have focused on the most recent literature to discuss the new findings and insights on the role of different immune cells in the context of OPSCC and its etiology. We then applied this knowledge to describe potential biomarkers and analyzed the rationale and outcomes of earlier and ongoing immunotherapy trials. Finally, we describe new developments that are still at the preclinical phase and provide an outlook on what the near future may bring, now that several new and exciting techniques to study the immune system at the single cell level are being exploited.

Immunomethylomics: A Novel Cancer Risk Prediction Tool

There is emerging evidence that the immune biology associated with lung and other solid tumors, as well as patient immune genetic traits, contributes to individual survival. At this time, dramatic advances in immunologic approaches to the study and management of human cancers are taking place, including lung and head and neck squamous cell carcinoma. However, major obstacles for therapies are the profound immune alterations in blood and in the tumor microenvironment that arise in tandem with the cancer. Although there is a significant current effort underway across the cancer research community to probe the tumor environment to uncover the dynamics of the immune response, little similar work is being done to understand the dynamics of immune alterations in peripheral blood, despite evidence showing the prognostic relevance of the neutrophil/lymphocyte ratio for these cancers. A prominent feature of cancer-associated inflammation is the generation of myeloid-derived suppressor cells, which arise centrally in bone marrow myelopoiesis and peripherally in response to tumor factors. Two classes of myeloid-derived suppressor cells are recognized: granulocytic and monocytic. To date, such immune factors have not been integrated into molecular classification or prognostication. Here, we advocate for a more complete characterization of patient immune profiles, using DNA from archival peripheral blood after application of methylation profiling (immunomethylomics). At the heart of this technology are cell libraries of differentially methylated regions that provide the "fingerprints" of immune cell subtypes. Going forward, opportunities exist to explore aberrant immune profiles in the context of cancer-associated inflammation, potentially adding significantly to prognostic and mechanistic information for solid tumors.

Radiotherapy-Induced Changes in the Systemic Immune and Inflammation Parameters of Head and Neck Cancer Patients

Though radiotherapy is a local therapy, it has systemic effects mainly influencing immune and inflammation processes. This has important consequences in the long-term prognosis and therapy individualization. Our objective was to investigate immune and inflammation-related changes in the peripheral blood of head and neck cancer patients treated with radiotherapy. Peripheral blood cells, plasma and blood cell-derived RNA were isolated from 23 patients before and at two time points after radiotherapy and cellular immune parameters, plasma protein changes and gene expression alterations were studied. Increased regulatory T cells and increased CTLA4 and PD-1 expression on CD4 cells indicated an immune suppression induced by the malignant condition, which was accentuated by radiotherapy. Circulating dendritic cells were strongly elevated before treatment and were not affected by radiotherapy. Decreased endoglin levels in the plasma of patients before treatment were further decreased by radiotherapy. Expression of the FXDR, SESN1, GADD45, DDB2 and MDM2 radiation-response genes were altered in the peripheral blood cells of patients after radiotherapy. All changes were long-lasting, detectable one month after radiotherapy. In conclusion we demonstrated radiotherapy-induced changes in systemic immune parameters of head and neck cancer patients and proposed markers suitable for patient stratification worth investigating in larger patient cohorts.

Prognostic Significance of Peripheral T-Cell Subsets in Laryngeal Squamous Cell Carcinoma

Objectives

The role of the immune system in head and neck squamous cell carcinoma is controversial. The aim of our study was to analyze full blood counts and distribution of T cell subsets in patients affected by laryngeal squamous cell cancer (LSCC) and their association with clinical variables and survival.

Study design

Retrospective study.

Methods

We analyzed the levels of platelets, lymphocytes, and neutrophils, as well as the CD4⁺, CD8⁺, and CD3⁺ T‐cell subpopulations by cytofluorometry in LSCC patients. A cohort of healthy patients was used as control group. The disease‐specific survival (DSS) was considered as survival outcome.

Results

Sixty‐five LSCC patients and 48 controls were enrolled. In LSCC patients, neutrophils were higher than in the healthy group (P < .0001). The neutrophil‐to‐lymphocyte ratio (NLR) and the platelet‐to‐lymphocyte ratio (PLR) were both higher in LSCC patients (P < .0001). In patients treated for recurrent disease, the CD8⁺/CD3⁺ ratio was increased (P = .02), while the CD4⁺/CD8⁺ (P = .03) and CD4⁺/CD3⁺ (P = .04) ratios were lower. In patients with lymph node metastases, leukocytes (P = .03), CD3⁺ (P = .04), and CD4⁺ (P = .0098) were all higher. Among Stages III‐IV patients, low lymphocyte and low leukocyte count were associated with worse DSS.

Conclusion

Our data demonstrate that NLR and PLR are significantly increased in LSCC. Lower CD4⁺/CD8⁺ and CD3⁺/CD8⁺ ratios are related to recurrent disease and a higher level of CD3⁺ and CD4⁺ is associated with nodal metastasis.

Level of Evidence

4

IFN-γ: A cytokine at the right time, is in the right place

Interferon gamma has long been studied as a critical mediator of tumor immunity. In recent years, the complexity of cellular interactions that take place in the tumor microenvironment has become better appreciated in the context of immunotherapy. While checkpoint inhibitors have dramatically improved remission rates in cancer treatment, IFN-γ and related effectors continue to be identified as strong predictors of treatment success. In this review, we provide an overview of the multiple immunosuppressive barriers that IFN-γ has to overcome to eliminate tumors, and potential avenues for modulating the immune response in favor of tumor rejection.

The Tolerogenic Function of Regulatory T Cells in Pregnancy and Cancer

Regulatory T cells, a subpopulation of suppressive T cells, are potent mediators of self-tolerance and essential for the suppression of triggered immune responses. The immune modulating capacity of these cells play a major role in both transplantation, autoimmune disease, allergy, cancer and pregnancy. During pregnancy, low numbers of regulatory T cells are associated with pregnancy failure and pregnancy complications such as pre-eclampsia. On the other hand, in cancer, low numbers of immunosuppressive T cells are correlated with better prognosis. Hence, maternal immune tolerance toward the fetus during pregnancy and the escape from host immunosurveillance by cancer seem to be based on similar immunological mechanisms being highly dependent on the balance between immune activation and suppression. As regulatory T cells hold a crucial role in several biological processes, they may also be promising subjects for therapeutic use. Especially in the field of cancer, cell therapy and checkpoint inhibitors have demonstrated that immune-based therapies have a very promising potential in treatment of human malignancies. However, these therapies are often accompanied by adverse autoimmune side effects. Therefore, expanding the knowledge to recognize the complexities of immune regulation pathways shared across different immunological scenarios is extremely important in order to improve and develop new strategies for immune-based therapy. The intent of this review is to highlight the functional characteristics of regulatory T cells in the context of mechanisms of immune regulation in pregnancy and cancer, and how manipulation of these mechanisms potentially may improve therapeutic options.

Differential expression of Helios, Neuropilin-1 and FoxP3 in head and neck squamous cell carcinoma (HNSCC) patients

In recent years, studies have begun to explore the immune involvement in head and neck tumors. Advanced stage head and neck squamous cell carcinoma (HNSCC) has a poor prognosis with low survival rates with high level of immune infiltrates. Tregs (regulatory T cells) play a crucial role in constructing an immunosuppressive tumor microenvironment. In the present study, we highlighted specific Treg markers and its factors in HNSCC solid tumors and peripheral blood of cancer patients. By histopathology and immunofluorescence staining, we observed differential expression of CD4, CD25, Foxp3, Helios and Neuropilin-1. Further, we analyzed the expression of Foxp3, Helios, Neuropilin-1 and GARP by qPCR and flow cytometry in whole blood and found to be elevated in HNSCC patients in comparison with healthy donors. Additionally, IFN-γ, TGF-β, IL-6, IL-2, IL-10 and TNF-α expressions were also found to be relatively increased in the head and neck cancer patients when compared with healthy donors. Our findings emphasize that Tregs may be involved in promoting tumor progression. Helios and Neuropilin-1 could be potent markers in identifying subsets of Tregs. Association of soluble factors could sculpture the activity of Tregs. With further research, Treg markers and its associated soluble factors could be employed to block Tregs trafficking to the tumor, thus enlightening a potential strategy for targeting human cancers.

Effect of tumor microenvironment on pathogenesis of the head and neck squamous cell carcinoma: a systematic review

The tumor microenvironment (TME) is comprised of many different cell populations, such as cancer-associated fibroblasts and various infiltrating immune cells, and non-cell components of extracellular matrix. These crucial parts of the surrounding stroma can function as both positive and negative regulators of all hallmarks of cancer development, including evasion of apoptosis, induction of angiogenesis, deregulation of the energy metabolism, resistance to the immune detection and destruction, and activation of invasion and metastasis. This review represents a summary of recent studies focusing on describing these effects of microenvironment on initiation and progression of the head and neck squamous cell carcinoma, focusing on oral squamous cell carcinoma, since it is becoming clear that an investigation of differences in stromal composition of the head and neck squamous cell carcinoma microenvironment and their impact on cancer development and progression may help better understand the mechanisms behind different responses to therapy and help define possible targets for clinical intervention.

Deciphering the Role of Regulatory CD4 T Cells in Oral and Oropharyngeal Cancer: A Systematic Review

Background: Recruiting regulatory CD4 T cells (Tregs) into the tumor microenvironment is an important tumor escape mechanism. Diminishing these suppressive cells is therefore one of the targets of cancer immunotherapy. Selective depletion of Tregs has proven successful in enhancing anti-tumor immunity and therapeutic efficacy in multiple tumor types. However, the role of Tregs in oral/oropharyngeal cancers is unclear with conflicting evidence regarding the effect of these suppressive cells on tumor prognosis. In this study, we sought to review the role of Tregs in oral/oropharyngeal cancer with the aim of deciphering the controversy regarding their effect on tumor progression and prognosis.

Methods: A systematic review of the literature pertaining to the role of Tregs in oral/oropharyngeal cancer was performed using Scopus, Embase, and PubMed. Forty-five records were deemed eligible and data describing methodology of Treg detection, tumor type, and association with prognosis were extracted.

Results: Of the 45 eligible manuscripts accepted for this systematic review, thirty-nine studies reported data from human subjects while the remaining studies focused on animal models. Sixteen studies were carried out using peripheral blood samples, while samples from the tumor site were analyzed in 18 studies and 11 studies assessed both blood and tumor samples. The transcriptional factor, Foxp3, was the most commonly used marker for Treg identification (38/45). The findings of 25 studies suggested that an increase in Tregs in the tumor microenvironment and/or peripheral blood was associated with poorer prognosis. These conclusions were attributed to the suppression of immune responses and the consequent tumor progression. Conversely, nine studies showed an increase in Tregs in peripheral blood and/or tumor microenvironment was related to a favorable prognosis, particularly in the presence of human papilloma virus (HPV), the status of which was only assessed in 11 studies.

Conclusions: This review underlines the importance of host immunity in the behavior of oral/oropharyngeal cancer. Furthermore, we report an apparent lack of clarity regarding the true role Tregs play in oral/oropharyngeal cancer progression which could be attributed to inconsistent detection techniques of Tregs. Our results therefore highlight the need for clearer methodologies and more robust phenotyping when defining Tregs.

Immunohistochemical Analysis of Foxp3+, CD4+, CD8+ Cell Infiltrates and PD-L1 in Oral Squamous Cell Carcinoma

The immunoexpression of the PD-L1 and the number of immune infiltrating cells have been shown to be a significant prognostic factors in various human cancers. Immunohistochemical method was used to examine the immunoexpression of PD-L1 and number of Foxp3+, CD4+, CD8+ cells in 78 cases of oral squamous cell carcinomas (OSCCs): with better prognosis - OSCCBP (n = 37), and with poorer prognosis - OSCCPP (n = 41), and 18 cases of normal mucosa as a control. The immunoexpression of PD-L1 and the mean number of Foxp3+ cells was significantly increased in OSCCPP group in comparison to OSCCBP and control groups. The mean number of CD4+ cells was significantly increased in OSCCPP group in comparison to OSCCBP and control groups. CD8+ cells were significantly more numerous in OSCCBP group in comparison to OSCCPP and control group. In both OSCCPP and OSCCBP groups there were positive significant correlations between number of Foxp3+ and CD4+ cells. We found positive correlations between the immunoexpression of PD-L1 and numbers of Foxp3+ cells, and negative correlation between the immunoexpression of PD-L1 and numbers of CD8+ cells in both OSCCPP and OSCCBP groups. We found also significant positive correlation between immunoexpression of PD-L1 and the number of CD4+ cells in OSCCPP group. In conclusion, our findings support the hypothesis of involvement of Tregs and PD-L1 in OSCC development and progression.

Investigation of immune cell markers in feline oral squamous cell carcinoma

Squamous cell carcinoma is the most common oral cancer in the cat and presents as a locally aggressive lesion for which an effective therapeutic protocol remains elusive. Feline oral squamous cell carcinoma (OSCC) shares many clinical characteristics with human head and neck squamous cell carcinoma (HNSCC). Accordingly, present studies were conducted to determine similarities for immune markers shared by feline OSCC and human HNSCC. Biopsies harvested from a feline patient cohort-1 (n = 12) were analyzed for lymphoid cell infiltrates by immunohistochemistry (IHC). Results revealed unique patterns of T cell infiltration involving both neoplastic epithelium and stroma that were detected in most patient tumor biopsies (92%) examined by IHC staining for CD3. Intratumoral B cell infiltrates were detected within tumor stroma only, based on IHC staining for CD79a and CD20 for all patients within the same cohort-1. Infiltration of tumors by a regulatory CD4 T cell subset (Tregs) defined by expression of the forkhead transcription factor FoxP3, was also detected in biopsies from 57% of patients and involved infiltration of neoplastic epithelium and stroma. Patient biopsies were also examined for expression of immunomodulator cyclooxygenase (COX)-2 and revealed positive but weak staining of neoplastic epithelium in a significant proportion of cases (75%). Interestingly, COX-2 expression was detected in both neoplastic epithelium and stroma. Blood collected from a second cohort of feline OSCC patients (n = 9) revealed an increased frequency of circulating CD4+FoxP3+ T cells when compared to healthy adult controls (n = 7) (P = 0.045), although frequencies of CD4+CD25+FoxP3+ T cells were comparable between patients and healthy pet cat controls. Lastly, biopsies from feline OSCC patients were characterized for histologic subtype using a classification scheme previously described for human HNSCC. This analysis revealed the conventional subtype as the predominant variant (75%) with conventional subtypes split evenly between well differentiated and moderately differentiated carcinomas. Two cases were classified as papillary and one case as basaloid subtypes. Correlations between subtype, immune marker scores or circulating Treg frequencies and clinical characteristics or outcome were not detected, most likely due to small patient numbers within patient cohorts. However, findings from these studies provide a preliminary step in the characterization of immune and histologic markers that will be critical to defining prognostic immune markers for feline OSCC and potential targets for testing of immunotherapeutics also relevant to human HNSCC in future studies.

Multifaceted Role of Neuropilins in the Immune System: Potential Targets for Immunotherapy

Neuropilins (NRPs) are non-tyrosine kinase cell surface glycoproteins expressed in all vertebrates and widely conserved across species. The two isoforms, such as neuropilin-1 (NRP1) and neuropilin-2 (NRP2), mainly act as coreceptors for class III Semaphorins and for members of the vascular endothelial growth factor family of molecules and are widely known for their role in a wide array of physiological processes, such as cardiovascular, neuronal development and patterning, angiogenesis, lymphangiogenesis, as well as various clinical disorders. Intriguingly, additional roles for NRPs occur with myeloid and lymphoid cells, in normal physiological as well as different pathological conditions, including cancer, immunological disorders, and bone diseases. However, little is known concerning the molecular pathways that govern these functions. In addition, NRP1 expression has been characterized in different immune cellular phenotypes including macrophages, dendritic cells, and T cell subsets, especially regulatory T cell populations. By contrast, the functions of NRP2 in immune cells are less well known. In this review, we briefly summarize the genomic organization, structure, and binding partners of the NRPs and extensively discuss the recent advances in their role and function in different immune cell subsets and their clinical implications.

HNSCC subverts PBMCs to secrete soluble products that promote tumor cell proliferation

The immune system detects shifts from homeostasis and eliminates altered cells. However, neoplastic cells can modulate the host response to escape immunosurveillance thereby allowing tumor progression. Head and neck squamous cell carcinoma (HNSCC) is one of the most immunosuppressive cancers but its role in co-opting the immune system to actively promote tumor growth has not been investigated. In this study, we investigated the influence of soluble factors secreted by HNSCC and non-neoplastic epithelial cells on proliferation, apoptosis, activation, cytokine gene expression and phenotypic polarization of immune cells of healthy donors. Then, we determined if the immunomodulation caused by HNSCC-derived soluble products leads to immunosubversion by assessing proliferation, migration and survival of tumor cells exposed to soluble products secreted by modulated immune cells or co-cultured with immune cells. Soluble products from HNSCC inhibited proliferation and cytokine expression in PBMCs, activation of T cells, and polarization of CD4+ towards the Th17 phenotype. These changes co-opted the immune cells to favor cell proliferation, survival and migration of HNSCC. This immunosubversion was observed both indirectly with secreted products and with direct cell-to-cell contact. We conclude that HNSCC-derived secreted products create an immunosuppressive environment that facilitates evasion of tumor cells and subverts the immune cells into a pro-tumoral phenotype.

Cytokine-induced killer cell therapy for modulating regulatory T cells in patients with non-small cell lung cancer

Previous studies have reported that regulatory T cells (Tregs), which are physiologically engaged in the maintenance of immunological self-tolerance, have a critical role in the regulation of the antitumor immune response. Targeting Tregs has the potential to augment cancer vaccine approaches. The current study therefore aimed to evaluate the role of cytokine-induced killer (CIK) cell infusion in modulating Tregs in patients with non-small cell lung cancer (NSCLC). A total of 15 patients with advanced NSCLC were treated by an infusion of CIK cells derived from autologous peripheral blood mononuclear cells (PBMCs). By using flow cytometry and liquid chip analysis, subsets of T cells and natural killer (NK) cells in peripheral blood, and plasma cytokine profiles in the treated patients, were analyzed at 2 and 4 weeks after CIK cell infusion. Cytotoxicity of PBMCs (n=15) and NK cells (n=6) isolated from NSCLC patients was evaluated before and after CIK cell therapy. Progression-free survival (PFS) and overall survival (OS) were also assessed. Analysis of the immune cell populations before and after treatment showed a significant increase in NK cells (P<0.05) concomitant with a significant decrease in Tregs (P<0.01) at 2 weeks post-infusion of CIK cells compared with the baseline. NK group 2D receptor (NKG2D) expression on NK cells was also significantly increased at 2 weeks post-infusion compared with the baseline (P<0.05). There was a positive correlation between NKG2D expression and the infusion number of CIK cells (P<0.05). When evaluated at 2 weeks after CIK cell therapy, the cytotoxicity of PBMCs and isolated NK cells was significantly increased compared with the baseline (P<0.01 and P<0.05). Correspondingly, plasma cytokine profiles showed significant enhancement of the following antitumor cytokines: Interferon (IFN)-γ (P<0.05), IFN-γ-inducible protein 10 (P<0.01), tumor necrosis factor-α (P<0.001), granulocyte-macrophage colony-stimulating factor (P<0.01), monocyte chemotactic protein-3 (P<0.01) and interleukin-21 (P<0.05) at 2 weeks post-infusion, compared with the baseline. At the same time, the expression of transforming growth factor-β1, which is primarily produced by Tregs, was significantly decreased compared with the baseline (P<0.05). Median PFS and OS in the CIK cell treatment group were significantly increased compared with the control group (PFS, 9.98 vs. 5.44 months, P=0.038; OS, 24.17 vs. 20.19 months, P=0.048). No severe side-effects were observed during the treatment period. In conclusion, CIK cell therapy was able to suppress Tregs and enhance the antitumor immunity of NK cells in advanced NSCLC patients. Therefore, CIK cell treatment may improve PFS and OS in patients with advanced NSCLC. CIK cell infusion may have therapeutic value for patients with advanced NSCLC, as a treatment that can be combined with chemotherapy and radiotherapy.

Interferon-γ Drives Treg Fragility to Promote Anti-tumor Immunity

Regulatory T cells (Tregs) are a barrier to anti-tumor immunity. Neuropilin-1 (Nrp1) is required to maintain intratumoral Treg stability and function but is dispensable for peripheral immune tolerance. Treg-restricted Nrp1 deletion results in profound tumor resistance due to Treg functional fragility. Thus, identifying the basis for Nrp1 dependency and the key drivers of Treg fragility could help to improve immunotherapy for human cancer. We show that a high percentage of intratumoral NRP1+ Tregs correlates with poor prognosis in melanoma and head and neck squamous cell carcinoma. Using a mouse model of melanoma where Nrp1-deficient (Nrp1-/-) and wild-type (Nrp1+/+) Tregs can be assessed in a competitive environment, we find that a high proportion of intratumoral Nrp1-/- Tregs produce interferon-γ (IFNγ), which drives the fragility of surrounding wild-type Tregs, boosts anti-tumor immunity, and facilitates tumor clearance. We also show that IFNγ-induced Treg fragility is required for response to anti-PD1, suggesting that cancer therapies promoting Treg fragility may be efficacious.

Frequently Increased but Functionally Impaired CD4+CD25+ Regulatory T Cells in Patients with Oral Lichen Planus

Oral lichen planus (OLP) is a T cell-mediated chronic inflammatory mucosal disease, and CD4(+)CD25(+) regulatory T cells (Tregs) are considered involved in the pathogenesis of OLP. In this study, to investigate whether there are intrinsic factors that might cause functional changes in Tregs in this disease, we evaluated the frequency of Tregs in peripheral blood and oral lesions and the expression levels of function-related transcription factors, forkhead/winged-helix transcription factor box P3 (FOXP3), transforming growth factor β (TGF-β), interleukin 10 (IL-10), and TGF-β receptors (TβRI and TβRII) mRNAs in Tregs of patients with oral lichen planus (OLP). We also investigated the frequency of pro-inflammatory cytokines (IFN-γ and IL-17A) producing Foxp3(+) regulatory cells. Increased proportions of Tregs were found in OLP patients. The expression of FOXP3 on mRNA and protein level was elevated in the Tregs of OLP. The expression of TGF-β was lower both on the mRNA and serum level, whereas the expression of IL-10 showed no significant difference between the OLP patients and normal controls. The percentages of CD4(+)FOXP3(+)IL-17(+) T cells were significantly higher than that of normal controls, whereas the percentages of CD4(+)FOXP3(+)IFN-γ(+) T cells did not differ significantly. Furthermore, impaired suppressive function of CD4(+)CD25(+) T cells was demonstrated in OLP patients by in vitro proliferation assay. These data indicate that Tregs in OLP are frequently expanded but functionally deficient. This could explain, at least in part, why the increased Tregs in OLP fail to control the pathogenesis and development of this autoimmune disease.

Immunological and angiogenic markers during metronomic temozolomide and cyclophosphamide in canine cancer patients

Metronomic chemotherapy stimulates the immune response via depletion of regulatory T cells (Tregs) and suppresses angiogenesis by modulating the secretion of thrombospondin-1 (TSP-1) and vascular endothelial growth factor (VEGF). In this study, blood was collected from 10 healthy dogs and from 30 canine cancer patients before and 2 and 4 weeks after treatment with metronomic temozolomide (6.6 mg m^-2 ), cyclophosphamide (12.5 mg m^-2 ) or cyclophosphamide and temozolomide. The percentage of circulating CD25⁺ Foxp3⁺ CD4⁺ Tregs and the plasma levels of TSP-1 and VEGF were measured. There was a significant difference in the percentage of Tregs between cancer patients and healthy dogs. A significant decrease in Tregs was noted in patients treated with metronomic cyclophosphamide and the combination. Treatment with temozolomide had no effect on the percentage of Tregs. TSP-1 and VEGF levels were, respectively, significantly lower and higher in cancer patients than in healthy dogs, but they were not influenced by any of the studied metronomic treatment regimens.

Immunophenotyping of patients with oral squamous cell carcinoma in peripheral blood and associated tumor tissue

The immune system is important for elimination of cancer cells. Tumors including oral squamous cell carcinoma (OSCC) are capable of escaping detection by host immune cells through apoptotic depletion of tumor-infiltrating lymphocytes (TILs). Circulating peripheral blood lymphocytes (PBLs) and corresponding TILs of tumor specimen were evaluated before and after curative tumor resection (n = 30) compared with PBLs of controls (n = 87). PBLs were characterized for the total number of T cells (CD3(+)), T helper cells (Th, CD3(+)/CD4(+)), regulatory T cells (Treg, CD4(+)/CD25(+)/CD127(low)), cytotoxic T cells (Tc, CD3(+)/CD8(+)), activated T cells (CD3(+)/HLA-DR(+)), and natural killer (NK) cells (CD3(-)/CD16(+)/CD56(+)). In tumor tissue, the prevalence of CD3(+), CD4(+), and CD8(+) TILs was assessed using immunohistochemistry, whereas the incidence of apoptosis was assessed using terminal deoxynucleotidyl transferase deoxyuridinetriphosphate nick-end labeling (TUNEL) assay. In PBLs of pretreated OSCC patients, a highly significant decrease in total number of T cells (p = 0.0001), Th cells (p < 0.0001), Treg cells (p < 0.0001), Tc cells (p < 0.0001), and NK cells (p = 0.0037) were found compared with controls. Decreased PBLs of OSCC patients were correlated with decreased numbers of corresponding TILs, which were associated with increased detection of apoptosis in the tumor tissue. Compared with the controls, the total number of T cells remained unchanged after surgery but the total number of NK cells significantly increased. Standardized immunophenotyping of OSCC may help to identify patients likely to benefit from cancer immunotherapy strategies and/or chemoradiation. Finally, future attempts to enhance an effective tumor-reactive immune response by immunotherapy or vaccination should be made by promoting tumor-specific Th and/or Tc cell/NK cell responses.

Cytokine and Adipokine Levels in Patients with Premalignant Oral Lesions or in Patients with Oral Cancer Who Did or Did Not Receive 1α,25-Dihydroxyvitamin D3 Treatment upon Cancer Diagnosis

Differences in levels of inflammation-modulating cytokines and adipokines in patients with premalignant oral lesions versus in patients that develop squamous cell carcinoma of the head and neck (HNSCC) were assessed. Also assessed was the impact of treating HNSCC patients with the immune regulatory mediator, 1α,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃], on modulators of inflammation. Compared to healthy controls, patients with premalignant oral lesions had increases in their systemic levels of the inflammatory cytokines IL-6 and IL-17, and increases in the adipokine, leptin. However, levels of these pro-inflammatory cytokines and adipokine were reduced in patients with HNSCC. Treatment of HNSCC patients with 1,25(OH)₂D₃ increased levels of each of the measured immune mediators. Levels of the anti-inflammatory adipokine, adiponectin, were shifted inversely with the levels of the pro-inflammatory cytokines and with leptin. These studies demonstrate heightened immune reactivity in patients with premalignant lesions, which wanes in patients with HNSCC, but which is restored by treatment with 1,25(OH)₂D₃.

Frequency, suppressive capacity, recruitment and induction mechanisms of regulatory T cells in sinonasal squamous cell carcinoma and nasal inverted papilloma

Background

Sinonasal squamous cell carcinoma (SSCC) and nasal inverted papilloma (NIP) represent the predominant type of malignant and benign tumors in sinonasal tract, respectively. CD4⁺CD25⁺Foxp3⁺ natural regulatory T (Treg) cells might play critical role(s) in the suppression of anti-tumor immune response and thus shed light on tumor progression from benign to malignant.

Objective

This study aimed to evaluate the frequency and suppressive capacity of Treg cells in SSCC compared to NIP and further to explore the underlying mechanisms.

Patients and Methods

Frequencies of Treg, Th1 and Th2 cells were evaluated by flow cytometry in tissue homogenate and peripheral blood from 31 SSCC patients, 32 NIP patients and 35 normal controls. Treg cells were tested for regulatory function by co-culture with effector T cells. CCR4 and its ligands, CCL22 and CCL17, were analyzed by flow cytometry and Luminex, respectively. The chemoattractant properties of CCR4/CCL22 and CCR4/CCL17 for Treg cells were assessed using the Boyden chamber technique, to elucidate the potential mechanisms of Treg recruitment in tumor microenvironment. Treg cells induction via TGF-β was assessed with transwells after local CD4⁺Foxp3⁺ T cells were assessed by immunohistochemistry and TGF-β concentration was measured by Luminex.

Results

Tumor-infiltrating Treg cells increased significantly from normal to NIP to SSCC (P ≤ 0.001 for normal vs. NIP and P = 0.004 for NIP vs. SSCC). Significantly elevated frequency and enhanced suppression capacity of circulating Treg cells in SSCC were detected compared to NIP and healthy controls, concomitant with Th1 decrease and Th2 increase. Apparently increased CCL22 attracted CCR4-expressing Treg cells to tumor microenvironment in SSCC, compared to NIP. SSCC produced significantly more TGF-β than NIP and thus possessed greater potential for Treg cell induction.

Conclusion

Frequency and suppressive capacity of Treg cells enhanced with progression of malignancy from NIP to SSCC. Circulating Treg cells were recruited to tumor tissue via CCR4/CCL22 signalling, whereas tumor-synthesised TGF-β contributed to induction of peripheral Treg cells.

Tadalafil reduces myeloid-derived suppressor cells and regulatory T cells and promotes tumor immunity in patients with head and neck squamous cell carcinoma

PURPOSE

Myeloid-derived suppressor cells (MDSC) and regulatory T cells (Treg) play a key role in the progression of head and neck squamous cell carcinoma (HNSCC). On the basis of our preclinical data demonstrating that phosphodiesterase-5 (PDE5) inhibition can modulate these cell populations, we evaluated whether the PDE5 inhibitor tadalafil can revert tumor-induced immunosuppression and promote tumor immunity in patients with HNSCC.

EXPERIMENTAL DESIGN

First, we functionally and phenotypically characterized MDSCs in HNSCCs and determined, retrospectively, whether their presence at the tumor site correlates with recurrence. Then, we performed a prospective single-center, double-blinded, randomized, three-arm study in which patients with HNSCC undergoing definitive surgical resection of oral and oropharyngeal tumors were treated with tadalafil 10 mg/day, 20 mg/day, or placebo for at least 20 days preoperatively. Blood and tumor MDSC and Treg presence and CD8(+) T-cell reactivity to tumor antigens were evaluated before and after treatment.

RESULTS

MDSCs were characterized in HNSCC and their intratumoral presence significantly correlates with recurrence. Tadalafil treatment was well tolerated and significantly reduced both MDSCs and Treg concentrations in the blood and in the tumor (P < 0.05). In addition, the concentration of blood CD8(+) T cells reactive to autologous tumor antigens significantly increased after treatment (P < 0.05). Tadalafil immunomodulatory activity was maximized at an intermediate dose but not at higher doses. Mechanistic analysis suggests a possible off-target effect on PDE11 at high dosages that, by increasing intracellular cAMP, may negatively affect antitumor immunity.

CONCLUSIONS

Tadalafil seems to beneficially modulate the tumor micro- and macro-environment in patients with HNSCC by lowering MDSCs and Tregs and increasing tumor-specific CD8(+) T cells in a dose-dependent fashion.

CD4+CD25hiCD127low regulatory T cells are increased in oral squamous cell carcinoma patients

Regulatory T cells (Tregs), a subset of CD4+ T cells plays a pivotal role in regulating the immune system. An increase in Treg numbers enables cancer progression by dampening the immune system and allowing tumor cells to evade immune detection and destruction. An increase in Treg numbers and expression of inhibitory cytokines including TGF-β and IL-10 are mechanisms by which Tregs exert their immune suppressive function. However, the presence of Tregs and inhibitory cytokines in oral cancer patients is still unclear. In this study, the presence of circulating Tregs in 39 oral cancer patients and 24 healthy donors was examined by studying the presence of the CD4+CD25hiCD127low cell population in their peripheral blood mononuclear cells using flow cytometry. Serum levels of TGF-β and IL-10 were measured by ELISA. T cell subsets of OSCC patients were found to differ significantly from healthy donors where a decrease in CD8+ cytotoxic T cells and an increase in Tregs (CD4+CD25hiCD127low) were observed. Further, the ratio of CD8+ T cells/Tregs was also decreased in patients compared to healthy donors. The presence of Tregs was accompanied by a decrease in IL-10 but not TGF-β secretion in OSCC patients when compared to donors; in addition, the analysis also revealed that an increased presence of Tregs was accompanied by better patient survival. Amongst OSCC patients, smokers had significantly higher levels of TGF-β. It is apparent that the immune system is compromised in OSCC patients and the characterization of the Treg subpopulation could form a basis for improving our understanding of the perturbations in the immune system that occur during OSCC tumorigenesis.

CD45RA-Foxp3high but not CD45RA+Foxp3low suppressive T regulatory cells increased in the peripheral circulation of patients with head and neck squamous cell carcinoma and correlated with tumor progression

Background

T regulatory cells (Tregs) contribute to the progression of head and neck squamous cell carcinoma (HNSCC) by suppressing antitumor immunity. However, little is known regarding the functional heterogeneity of Tregs in HNSCC patients.

Methods

Using multicolor flow cytometry, the frequency of three Treg subsets, separated on the basis of CD45RA and Foxp3, from the peripheral circulation of newly-presenting HNSCC patients (19 oral cavity squamous cell carcinoma, 20 hypopharyngeal squamous cell carcinoma, 18 nasopharyngeal squamous cell carcinoma, 19 oropharyngeal squamous cell carcinoma, and 36 laryngeal squamous cell carcinoma) were assessed with regard to 31 healthy donors and clinicopathological features. Moreover, the functional capacity of each Treg subsets was evaluated based on CD45RA and CD25 expression.

Results

The frequency of Tregs in the peripheral circulation of HNSCC patients as a whole cohort was higher than in healthy donors (P < 0.0001). However, the frequency of Tregs was similar between patients with oral cavity squamous cell carcinoma and healthy donors (P = 0.269). Further dividing Tregs into three subsets based on Foxp3 and CD45RA expression revealed that the frequency of CD45RA^-Foxp3^high Tregs and CD45RA^-Foxp3^lowCD4⁺ T cells in patients with HNSCC developing from different subsites was higher than in healthy donors (P < 0.0001, P < 0.0001), whereas the frequency of CD45RA⁺Foxp3^low Tregs was lower than in healthy donors (P < 0.0001). Functionally study revealed that CD45RA^-CD25⁺⁺⁺ Tregs significantly inhibit the proliferation of CD4⁺CD25^- T cells (P < 0.001) and secrete lower levels of cytokines (P < 0.01) compared with CD45RA^-CD25⁺⁺CD4⁺ T cells. Importantly, the frequency of CD45RA^-Foxp3^high Tregs positively correlate with tumor stage (P < 0.0001) and nodal status (P < 0.0001).

Conclusions

CD45RA^-Foxp3^high Tregs increase in the peripheral circulation of HNSCC patients, and correlate with tumor stage and nodal status; suggesting a role in tumor progression which may be manipulated by future immunotherapy.

Effect of the premalignant and tumor microenvironment on immune cell cytokine production in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is marked by immunosuppression, a state in which the established tumor escapes immune attack. However, the impact of the premalignant and tumor microenvironments on immune reactivity has yet to be elucidated. The purpose of this study was to determine how soluble mediators from cells established from carcinogen-induced oral premalignant lesions and HNSCC modulate immune cell cytokine production. It was found that premalignant cells secrete significantly increased levels of G-CSF, RANTES, MCP-1, and PGE₂ compared to HNSCC cells. Splenocytes incubated with premalignant supernatant secreted significantly increased levels of Th1-, Th2-, and Th17-associated cytokines compared to splenocytes incubated with HNSCC supernatant. These studies demonstrate that whereas the premalignant microenvironment elicits proinflammatory cytokine production, the tumor microenvironment is significantly less immune stimulatory and may contribute to immunosuppression in established HNSCC.