Prognostic significance of regulatory T cells in tumor

Advances in research on flavonoids in tumor immunotherapy (Review)

Cancer immunotherapy is an approach used in anti‑tumor treatment; however, its efficacy is limited to specific tumor types that are inherently sensitive to immune system modulation. Expanding the scope of indications and enhancing the efficacy of cancer immunotherapy are key goals for continued advancement. Flavonoids modulate the tumor‑immunosuppressive microenvironment. Integrating flavonoids with immunotherapeutic modalities, including cancer vaccines, immune checkpoint inhibitors and adoptive immune‑cell therapy, has potential in terms of augmenting the therapeutic efficacy of immunotherapy. The present review aimed to summarize flavonoids that enhance cancer immunotherapy, focusing on their underlying mechanisms and the application of nanotechnology to overcome inherent limitations such as poor solubility, low bioavailability, rapid metabolism, and instability under physiological conditions, thereby highlighting the potential of flavonoids in advancing cancer immunotherapy.

Circulating Tumor Microenvironment in Metastasis

Activation of invasion and metastasis is a central hallmark of cancer, contributing to the primary cause of death for patients with cancer. In the multistep metastatic process, cancer cells must infiltrate the circulation, survive, arrest at capillary beds, extravasate, and form metastatic clones in distant organs. However, only a small proportion of circulating tumor cells (CTC) successfully form metastases, with transit of CTCs in the circulation being the rate-limiting step. The fate of CTCs is influenced by the circulating tumor microenvironment (cTME), which encompasses factors affecting their biological behaviors in the circulation. This liquid and flowing microenvironment differs significantly from the primary TME or the premetastatic niche. This review summarizes the latest advancements in identifying the biophysical cues, key components, and biological roles of the cTME, highlighting the network among biophysical attributes, blood cells, and nonblood factors in cancer metastasis. In addition to the potential of the cTME as a therapeutic target for inhibiting metastasis, the cTME could also represent as a biomarker for predicting patient outcomes and developing strategies for treating cancer.

Transferrin Disassociates TCR from CD3 Signaling Apparatus to Promote Metastasis

Immune recognition and activation by the peptide-laden major histocompatibility complex-T cell receptor (TCR)-CD3 complex is essential for anti-tumor immunity. Tumors may escape immune surveillance by dissembling the complex. Here, we report that transferrin, which is overexpressed in patients with liver metastasis, disassociates TCR from the CD3 signaling apparatus by targeting the constant domain (CD) of T cell receptor α (TCRα), consequently suppresses T cell activation, and inhibits anti-metastatic and anti-tumor immunity. In mouse models of melanoma and lymphoma, transferrin overexpression exacerbates liver metastasis, while its knockdown, antibody, designed peptides, and CD mutation interfering with transferrin-TCRα interaction inhibit metastasis. This work reveals a novel strategy of tumor evasion of immune surveillance by blocking the coupling between TCRs and the CD3 signaling apparatus to suppress TCR activation. Given the conservation of CD and transferrin up-regulation in metastatic tumors, the strategy might be a common metastatic mechanism. Targeting transferrin-TCRα holds promise for anti-metastatic treatment.

Crucial roles of circulating tumor cells in the metastatic cascade and tumor immune escape: biology and clinical translation

Cancer-related deaths are mainly caused by metastatic spread of tumor cells from the primary lesion to distant sites via the blood circulation. Understanding the mechanisms of blood-borne tumor cell dissemination by the detection and molecular characterization of circulating tumor cells (CTCs) in the blood of patients with cancer has opened a new avenue in cancer research. Recent technical advances have enabled a comprehensive analysis of the CTCs at the genome, transcriptome and protein level as well as first functional studies using patient-derived CTC cell lines. In this review, we describe and discuss how research on CTCs has yielded important insights into the biology of cancer metastasis and the response of patients with cancer to therapies directed against metastatic cells. Future investigations will show whether CTCs leaving their primary site are more vulnerable to attacks by immune effector cells and whether cancer cell dissemination might be the 'Achilles heel' of metastatic progression. Here, we focus on the lessons learned from CTC research on the biology of cancer metastasis in patients with particular emphasis on the interactions of CTCs with the immune system. Moreover, we describe and discuss briefly the potential and challenges for implementing CTCs into clinical decision-making including detection of minimal residual disease, monitoring efficacies of systemic therapies and identification of therapeutic targets and resistance mechanisms.

Fine-tuning of regulatory T cells is indispensable for the metabolic steatosis-related hepatocellular carcinoma: A review

The majority of chronic hepatic diseases are caused by nutritional imbalance. These nutritional inequities include excessive intake of alcohol and fat, which causes alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD), respectively. The pathogenesis of hepatic diseases is mainly dependent on oxidative stress, autophagy, DNA damage, and gut microbiota and their metabolites. These factors influence the normal physiology of the liver and impact the hepatic microenvironment. The hepatic microenvironment contains several immune cells and inflammatory cytokines which interact with each other and contribute to the progression of chronic hepatic diseases. Among these immune cells, Foxp3⁺ CD4⁺ regulatory T cells (Tregs) are the crucial subset of CD4⁺ T cells that create an immunosuppressive environment. This review emphasizes the function of Tregs in the pathogenesis of ALD and NAFLD and their role in the progression of NAFLD-associated hepatocellular carcinoma (HCC). Briefly, Tregs establish an immunosuppressive landscape in the liver by interacting with the innate immune cells and gut microbiota and their metabolites. Meanwhile, with the advancement of steatosis, these Tregs inhibit the proliferation, activation and functions of other cytotoxic T cells and support the progression of simple steatosis to HCC. Briefly, it can be suggested that targeting Tregs can act as a favourable prognostic indicator by modulating steatosis and insulin resistance during the pathogenesis of hepatic steatosis and NAFLD-associated HCC.

IDO Inhibitor and Gallic Acid Cross-Linked Small Molecule Drug Synergistic Treatment of Melanoma

In this study, we synthesized a molecule GA-1MT (GM) composed of indoleamine 2,3-dioxygenase (IDO) inhibitor (1-methyl-d-tryptophan, 1MT) called NLG8189 and gallic acid (GA) and verified its therapeutic effect on B16F10 melanoma cells and an orthotopic tumor-bearing mouse model. The synthesized molecule GM was analyzed by 1H NMR and mass spectrometry (MS). In addition, we confirmed that GM could mediate the immune response in the B16F10 cell tumor model by flow cytometry and immunofluorescence. The synthesized GM molecule could increase the solubility of 1MT to enhance the drug efficacy and lower costs. Moreover, GM could inhibit melanoma growth by combining 1MT and GA. In vivo experiments showed that GM could effectively inhibit the expression of tyrosinase, regulate the proportion of CD4+ T cells, CD8+ T cells, and regulatory T cells (Treg cells) in tumors, and significantly suppress melanoma growth. The newly synthesized drug GM could more effectively inhibit melanoma than GA and 1MT alone or in combination.

Research Progress on the Role of Regulatory T Cell in Tumor Microenvironment in the Treatment of Breast Cancer

The tumor microenvironment (TME) is a complex ecosystem comprised of cancer cells, stromal cells, and immune cells. Analysis of the composition of TME is essential to assess the prognosis of patients with breast cancer (BC) and the efficacy of different regimes. Treg plays a crucial role in the microenvironment of breast cancer subtypes, and its function contributes to the development and progression of BC by suppressing anti-tumor immunity directly or indirectly through multiple mechanisms. In addition, conventional treatments, such as anthracycline-based neoadjuvant chemotherapy, and neo-therapies, such as immune-checkpoint blockades, have a significant impact on the absence of Tregs in BC TME, thus gaining additional anti-tumor effect to some extent. Strikingly, Treg in BC TME revealed the predicted efficacy of some therapeutic strategies. All these results suggest that we can manipulate the abundance of Treg to achieve the ultimate effect of both conventional and novel treatments. In this review, we discuss new insights into the characteristics of Treg in BC TME, the impact of different regiments on Treg, and the possibilities of Treg as a predictive marker of efficacy for certain treatments.

Evaluation of lymphocyte-specific programmed cell death protein 1 receptor expression and cytokines in blood and urine in canine urothelial carcinoma patients

Urothelial carcinoma (UC) is the most common urinary tumour in dogs. Despite a range of treatment options, prognosis remains poor in dogs. In people, breakthroughs with checkpoint inhibitors have established new standards of care for muscle-invasive bladder cancer patients and elevated levels of programmed cell death protein 1 (PD-1) suggest immune checkpoint blockade may be a novel target for therapy. The goal of this study was to determine if canine UC patients express elevated levels of lymphocyte-specific PD-1 and/or urinary cytokine biomarkers compared to healthy dogs. Paired blood and urine were evaluated in 10 canine UC patients, five cystitis patients and 10 control dogs for lymphocyte-specific PD-1 expression via flow cytometry and relative cytokine expression. In UC patients, PD-1 expression was significantly elevated on CD8⁺ lymphocytes in urine samples. UC patients had a higher CD4:CD8 ratio in their urine compared to healthy dogs, however, there was no significant variation in the CD8:Treg ratio between any group. Cystitis patients had significantly elevated levels of CD4⁺ T cells, CD8⁺ T cells and Tregs in their blood samples compared to UC patients and healthy dogs. Cytokine analysis demonstrated significant elevations in urinary cytokines (granulocyte-macrophage colony-stimulating factor, interferon-gamma [IFN-γ], interleukin (IL)-2, IL-6 IL-7, IL-8 and IL-15, IP-10, KC-like, IL-18, monocyte chemoattractant protein-1 and tumour necrosis factor-alpha). Several of these cytokines have been previously correlated with both lymphocyte-specific PD-1 expression (IFN-γ, IL-2, IL-7 and IL-15) in muscle-invasive urothelial carcinoma in humans. Our results provide evidence of urinary lymphocyte PD-1 expression and future studies could elucidate whether veterinary UC patients will respond favourably to anti-PD-1 immune checkpoint inhibitor therapy.

Prognostic Implications of Intratumoral and Peritumoral Infiltrating Lymphocytes in Pancreatic Ductal Adenocarcinoma

This study aimed to elucidate the prognostic implications of intratumoral and peritumoral infiltrating T-lymphocytes in pancreatic ductal adenocarcinoma (PDAC) through a meta-analysis. A total of 18 eligible studies and 2453 PDAC patients were included in the present study. Intratumoral and peritumoral infiltrating lymphocytes were evaluated using various markers, such as CD3, CD4, CD8, FOXP3, and immune cell score. The correlations between these parameters and overall and disease-free survival were investigated and used in the meta-analysis. High intratumoral infiltration of CD3-, CD4-, and CD8-expressing lymphocytes was significantly correlated with better overall survival (hazard ratio (HR) 0.747, 95% confidence interval (CI) 0.620-0.900, HR 0.755, 95% CI 0.632-0.902, and HR 0.754, 95% CI 0.611-0.930, respectively). However, there was no significant correlation between PDAC prognosis and intratumoral FOXP3 or immune cell score (HR 1.358, 95% CI 1.115-1.655 and HR 0.776, 95% CI 0.566-1.065, respectively). Moreover, there was no significant correlation between the prognosis and peritumoral infiltrating T-lymphocytes. In evaluations of disease-free survival, only high intratumoral CD4 infiltration was correlated with a better prognosis (HR 0.525, 95% CI 0.341-0.810). Our results showed that high intratumoral infiltrating lymphocytes were significantly correlated with a better PDAC prognosis. However, among the tumor-infiltrating lymphocytes, CD3, CD4, and CD8 had prognostic implications, but not FOXP3 and immune cell score.

The prognostic value of intratumoral and peritumoral tumor-infiltrating FoxP3+Treg cells in of pancreatic adenocarcinoma: a meta-analysis

Background

Tumor-infiltrating lymphocytes (TILs) are major participants in the tumor microenvironment. The prognostic value of TILs in patients with pancreatic cancer is still controversial.

Methods

The aim of our meta-analysis was to determine the impact of FoxP3+Treg cells on the survival of pancreatic cancer patients. We searched for related studies in PubMed, EMBASE, Ovid, and Cochrane Library from the time the databases were established to Mar 30, 2017. We identified studies reporting the prognostic value of FoxP3+Treg cells in patients with pancreatic cancer. Overall survival (OS) and disease-free survival (DFS)/progression-free survival (PFS)/relapse-free survival (RFS) were investigated by pooling the data. The pooled hazard ratios (HRs) with 95% confidence intervals (95% CI) were used to evaluate the association between FoxP3+Treg cells and survival outcomes of pancreatic cancer patients. A total of 972 pancreatic cancer patients from 8 studies were included in our meta-analysis.

Results

High levels of infiltration with FoxP3+Treg cells were significantly associated with poor OS (HR=2.13; 95% CI 1.64–2.77; P<0.05) and poor DFS/PFS/RFS (HR=1.70; 95% CI 1.04 ~ 2.78; P< 0.05). Similar results were also observed in the peritumoral tissue; high levels of FoxP3+Treg cells were associated with poor OS (HR =2.1795% CI, CI 1.50–3.13).

Conclusion

This meta-analysis indicated that high levels of intratumoral or peritumoral FoxP3+Treg cell infiltration could be recognized as a negative factor in the prognosis of pancreatic cancer.

Impact of regulatory T cells on the prognosis of hepatocellular carcinoma: A protocol for systematic review and meta analysis

BACKGROUND

This meta-analysis aimed to systematically review current available literature to assess the impact of regulatory T cells (Tregs) on the prognosis of hepatocellular carcinoma (HCC).

METHODS

We will browse the online databases of PubMed and Cochrane Library. The summary hazard ratio (HR) and their 95% confidence intervals (CIs) will be combined to present the value reported in the study.

CONCLUSION

Our meta-analysis will provide useful guidance in treatment of HCC based on the reported evidences regarding the impact of Tregs on the prognosis of HCC.

OSF REGISTRATION NUMBER

10.17605/OSF.IO/3Q8PW.

Tumor-Induced Metabolism and T Cells Located in Tumor Environment

Several subtypes of T cells are located in a tumor environment, each of which supplies their energy using different metabolic mechanisms. Since the cancer cells require high levels of glucose, the conditions of food poverty in the tumor environment can cause inactivation of immune cells, especially the T-effector cells, due to the need for glucose in the early stages of these cells activity. Different signaling pathways, such as PI3K-AKt-mTOR, MAPK, HIF-1α, etc., are activated or inactivated by the amount and type of energy source or oxygen levels that determine the fate of T cells in a cancerous environment. This review describes the metabolites in the tumor environment and their effects on the function of T cells. It also explains the signaling pathway of T cells in the tumor and normal conditions, due to the level of access to available metabolites and subtypes of T cells in the tumor environment.

The Tumor Microenvironment: A Milieu Hindering and Obstructing Antitumor Immune Responses

The success of cancer immunotherapy relies on the knowledge of the tumor microenvironment and the immune evasion mechanisms in which the tumor, stroma, and infiltrating immune cells function in a complex network. The potential barriers that profoundly challenge the overall clinical outcome of promising therapies need to be fully identified and counteracted. Although cancer immunotherapy has increasingly been applied, we are far from understanding how to utilize different strategies in the best way and how to combine therapeutic options to optimize clinical benefit. This review intends to give a contemporary and detailed overview of the different roles of immune cells, exosomes, and molecules acting in the tumor microenvironment and how they relate to immune activation and escape. Further, current and novel immunotherapeutic options will be discussed.

A mathematical solution to Peto's paradox using Polya's urn model: implications for the aetiology of cancer in general

Ageing is the leading risk factor for the emergence of cancer in humans. Accumulation of pro-carcinogenic events throughout life is believed to explain this observation; however, the lack of direct correlation between the number of cells in an organism and cancer incidence, known as Peto's Paradox, is at odds with this assumption. Finding the events responsible for this discrepancy can unveil mechanisms with potential uses in prevention and treatment of cancer in humans. On the other hand, the immune system is important in preventing the development of clinically relevant tumours by maintaining a fine equilibrium between reactive and suppressive lymphocyte clones. It is suggested here that the loss of this equilibrium is what ultimately leads to increased risk of cancer and to propose a mechanism for the changes in clonal proportions based on decreased proliferative capacity of lymphocyte clones as a natural phenomenon of ageing. This mechanism, being a function of the number of cells, provides an explanation for Peto's Paradox.

Tumor infiltrating lymphocytes in malignant melanoma - allies or foes?

This is an overview of current problematics regarding the role of tumor infiltrating lymphocytes (TILs) in malignant melanomas. Various and often conflicting data have been published, correlating tumor type, stage, prognosis, as well as sex and age of patients. This is partly due to heterogeneity in scaling systems and unstandardized TILs grading but also due to changes of tumor-host interactions. Melanomas are an immunologically heterogeneous group with variability of TILs, where distinct gene expression patterns were found in tumors with absent, and/or non- brisk TIL grade versus brisk TIL grade. However, the presence of TILs alone appears to be inadequate for implicating them as immunologically functional. Further characterisation of TIL phenotype and function is warranted. This especially concerns, evaluation of TILs of the suppressor phenotype but rather than as a prognostic factor, more for prediction of targeted immunotherapy.

Conceptual Development of Immunotherapeutic Approaches to Gastrointestinal Cancer

Gastrointestinal (GI) cancer is one of the common causes of cancer-related death worldwide. Chemotherapy and/or immunotherapy are the current treatments, but some patients do not derive clinical benefits. Recently, studies from cancer molecular subtyping have revealed that tumor molecular biomarkers may predict the immunotherapeutic response of GI cancer patients. However, the therapeutic response of patients selected by the predictive biomarkers is suboptimal. The tumor immune-microenvironment apparently plays a key role in modulating these molecular-determinant predictive biomarkers. Therefore, an understanding of the development and recent advances in immunotherapeutic pharmacological intervention targeting tumor immune-microenvironments and their potential predictive biomarkers will be helpful to strengthen patient immunotherapeutic efficacy. The current review focuses on an understanding of how the host-microenvironment interactions and the predictive biomarkers can determine the efficacy of immune checkpoint inhibitors. The contribution of environmental pathogens and host immunity to GI cancer is summarized. A discussion regarding the clinical evidence of predictive biomarkers for clinical trial therapy design, current immunotherapeutic strategies, and the outcomes to GI cancer patients are highlighted. An understanding of the underlying mechanism can predict the immunotherapeutic efficacy and facilitate the future development of personalized therapeutic strategies targeting GI cancers.

Human regulatory T cells (Treg) and their response to cancer

INTRODUCTION

Regulatory T cells (Treg) and their role in health and disease is being intensively investigated. Today, human Treg emerge as a highly heterogeneous subset of CD4+ T cells which mediate immune suppression but also regulate responses of non-immune cells. In cancer, Treg occupy a critical although not yet entirely understood role.

AREAS COVERED

Newly acquired insights into Treg indicate a much greater plasticity and functional heterogeneity of this T cell subset than was previously known. Functional redundancy of Treg and their interactions with a variety of immune and non-immune cellular targets emphasize the central role Treg play in cancer. Treg not only regulate the host responses to cancer; they may also regulate responses to immune therapies. The impact of immune checkpoint blockade on Treg survival, stability and suppressive activity remains to be elucidated. T cell reprogramming by tumor-derived factors, including tumor-derived exosomes (TEX), plays a key role in shaping the Treg repertoire in the tumor microenvironment (TME). The reprogrammed or induced iTreg acquire capabilities to strongly down-regulate anti-tumor immune responses by mechanisms that are specific for each TME. Therapeutic silencing of such Treg calls for the discrimination of "bad" from "good" Treg subsets, an approach that remains elusive in the absence of a definitive "Treg signature."

EXPERT OPINION

Context-related plasticity and heterogeneity of Treg in the TME are significant barriers to selective therapeutic depletion of those Treg subsets that are reprogramed by the tumor to suppress anti-tumor immunity.

Anti-tumor activity and mechanism of oligoclonal hepatocellular carcinoma tumor-infiltrating lymphocytes in vivo and in vitro

Objective: To explore a method for culturing hepatocellular carcinoma and tumor-infiltrating lymphocytes (HCC-TIL) and investigate the mechanism of TIL in killing tumors. Methods: The distribution of regulatory T cells (Treg) in HCC was detected by immunohistochemistry. Conventional TIL and oligoclonal TIL were isolated by the traditional method of enzyme digestion combined with mechanical treatment for whole HCC and micro HCC tissue block culturing method. MTT was used to compare the killing activity of TIL. Flow cytometry was used to analyze the proportion of CD8+ T cells and Treg cells in TIL. Tumor-bearing mice were established, and TIL adoptive immunotherapy was performed. Results: Treg cells were mainly distributed in the stroma of HCC. In vitro experiments showed oligoclonal TIL had higher cytotoxicity to tumor cells which negatively correlated with the proportion of Treg cells. In vivo experiments showed oligoclonal TIL had a higher anti-tumor effect. IFN-γ in peripheral blood and the positive rate of intratumoral lymphocytic infiltration in oligoclonal TIL group were both higher. TGF-β and IL-10 in peripheral blood and the positive rate of intratumoral FoxP3 and IL-17 were both lower than those in conventional TIL group. Conclusion: The oligoclonal TIL culture method could obtain TIL with higher purity, and cytotoxicity to tumor cells was associated with Treg cells. The oligoclonal TIL had cytotoxicity to autologous HCC cells and significant inhibitory effect on the growth of transplanted tumors. The mechanism might be associated with the inhibition of Treg cells proliferation, increase of IFN-γ secretion, and decrease of TGF-β, IL-10, and IL-17 secretion.

The Different Functional Distribution of "Not Effector" T Cells (Treg/Tnull) in Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer worldwide, ranking as high as the second leading cause of cancer-related deaths in industrialized countries. Consistent with immunosurveillance theory, the immune system is crucial to protect the host from developing tumors, and the major players in tumoral immunity are effector T cells. Anyway, cancer cells develop strategies of immunoevasion influencing the cancer-specific lymphocyte priming, activation, and effector function. Therefore, the T cell subsets that mature during the stages of tumor growth, differently contribute to disease progression and/or regression. In our study, we analyzed the intra-tumoral and peripheral T cell subsets' distribution in 30 patients with CRC, in order to clarify their functional role toward cancer. We found that percentage of infiltrating effector T cells decreased in cancer tissue than in healthy mucosa and that the tumor microenvironment negatively influences the cytolytic activity of T lymphocytes reactive to cancer cells. Moreover, we found that the tumor tissue was infiltrated by a large amount of "not effector" T (neT) cells with a regulatory or an anergic profile, which are unable to kill cancer cells, may be contributing to the CRC promotion. The presence of neT cells was investigated also in the peripheral blood of CRC patients, demonstrating that the peripheral T regulatory cells can inhibit the proliferation of effector T cells, confirming their immunosuppressive properties. Finally, monitoring the changes in circulating neT cells' frequencies after the tumor removal, we confirmed the role of cancer in the modulation of immune system, in particular, in supporting a Tregs-mediated immunosuppression.

Contribution of Adipose Tissue to Development of Cancer

Solid tumor growth and metastasis require the interaction of tumor cells with the surrounding tissue, leading to a view of tumors as tissue-level phenomena rather than exclusively cell-intrinsic anomalies. Due to the ubiquitous nature of adipose tissue, many types of solid tumors grow in proximate or direct contact with adipocytes and adipose-associated stromal and vascular components, such as fibroblasts and other connective tissue cells, stem and progenitor cells, endothelial cells, innate and adaptive immune cells, and extracellular signaling and matrix components. Excess adiposity in obesity both increases risk of cancer development and negatively influences prognosis in several cancer types, in part due to interaction with adipose tissue cell populations. Herein, we review the cellular and noncellular constituents of the adipose "organ," and discuss the mechanisms by which these varied microenvironmental components contribute to tumor development, with special emphasis on obesity. Due to the prevalence of breast and prostate cancers in the United States, their close anatomical proximity to adipose tissue depots, and their complex epidemiologic associations with obesity, we particularly highlight research addressing the contribution of adipose tissue to the initiation and progression of these cancer types. Obesity dramatically modifies the adipose tissue microenvironment in numerous ways, including induction of fibrosis and angiogenesis, increased stem cell abundance, and expansion of proinflammatory immune cells. As many of these changes also resemble shifts observed within the tumor microenvironment, proximity to adipose tissue may present a hospitable environment to developing tumors, providing a critical link between adiposity and tumorigenesis. © 2018 American Physiological Society. Compr Physiol 8:237-282, 2018.

Lack of MHC class II molecules favors CD8+ T-cell infiltration into tumors associated with an increased control of tumor growth

Regulatory T-cells (Tregs) are crucial for the maintenance of immune tolerance and homeostasis as well as for preventing autoimmune diseases, but their impact on the survival of cancer patients remains controversial. In the TC-1 mouse model of human papillomavirus (HPV)-related carcinoma, we have previously demonstrated that the therapeutic efficacy of the CyaA-E7-vaccine, targeting the HPV-E7 antigen, progressively declines with tumor growth, in correlation with increased intratumoral recruitment of Tregs. In the present study, we demonstrated that these TC-1 tumor-infiltrating Tregs were highly activated, with increased expression of immunosuppressive molecules. Both intratumoral effector CD4⁺ T-cells (Teffs) and Tregs expressed high levels of PD-1, but anti-PD-1 antibody treatment did not impact the growth of the TC-1 tumor nor restore the therapeutic effect of the CyaA-E7 vaccine. To analyze the mechanisms by which Tregs are recruited to the tumor site, we used MHC-II KO mice with drastically reduced numbers of CD4⁺ effector T-cells. We demonstrated that these mice still had significant numbers of Tregs in their lymphoid organs which were recruited to the tumor. In MHC-II KO mice, the growth of the TC-1 tumor was delayed in correlation with a strong increase in the intratumoral recruitment of CD8⁺ T-cells. In addition, in mice that spontaneously rejected their tumors, the infiltration of E7-specific CD8⁺ T-cells was significantly higher than in MHC-II KO mice with a growing tumor. These results demonstrate that tumor-specific CD8⁺ T-cells can be efficiently activated and recruited in the absence of MHC class II molecules and of CD4⁺ T-cell help.

A bispecific nanobody approach to leverage the potent and widely applicable tumor cytolytic capacity of Vγ9Vδ2-T cells

Though Vγ9Vδ2-T cells constitute only a small fraction of the total T cell population in human peripheral blood, they play a vital role in tumor defense and are therefore of major interest to explore for cancer immunotherapy. Vγ9Vδ2-T cell-based cancer immunotherapeutic approaches developed so far have been generally well tolerated and were able to induce significant clinical responses. However, overall results were inconsistent, possibly due to the fact that these strategies induced systemic activation of Vγ9Vδ2-T cells without preferential accumulation and targeted activation in the tumor. Here we show that a novel bispecific nanobody-based construct targeting both Vγ9Vδ2-T cells and EGFR induced potent Vγ9Vδ2-T cell activation and subsequent tumor cell lysis both in vitro and in an in vivo mouse xenograft model. Tumor cell lysis was independent of KRAS and BRAF tumor mutation status and common Vγ9Vδ2-T cell receptor sequence variations. In combination with the conserved monomorphic nature of the Vγ9Vδ2-TCR and the facile replacement of the tumor-specific nanobody, this immunotherapeutic approach can be applied to a large group of cancer patients.

Delineation of an immunosuppressive gradient in hepatocellular carcinoma using high-dimensional proteomic and transcriptomic analyses

The recent development of immunotherapy as a cancer treatment has proved effective over recent years, but the precise dynamics between the tumor microenvironment (TME), nontumor microenvironment (NTME), and the systemic immune system remain elusive. Here, we interrogated these compartments in hepatocellular carcinoma (HCC) using high-dimensional proteomic and transcriptomic analyses. By time-of-flight mass cytometry, we found that the TME was enriched in regulatory T cells (Tregs), tissue resident memory CD8⁺ T cells (T_RMs), resident natural killer cells (NK_Rs), and tumor-associated macrophages (TAMs). This finding was also validated with immunofluorescence staining on Foxp3⁺CD4⁺ and PD-1⁺CD8⁺ T cells. Interestingly, Tregs and T_RMs isolated from the TME expressed multiple markers for T-cell exhaustion, including PD-1, Lag-3, and Tim-3 compared with Tregs and T_RMs isolated from the NTME. We found PD-1⁺ T_RMs were the predominant T-cell subset responsive to anti-PD-1 treatment and significantly reduced in number with increasing HCC tumor progression. Furthermore, T-bet was identified as a key transcription factor, negatively correlated with PD-1 expression on memory CD8⁺ T cells, and the PD-1:T-bet ratio increased upon exposure to tumor antigens. Finally, transcriptomic analysis of tumor and adjacent nontumor tissues identified a chemotactic gradient for recruitment of TAMs and NK_Rs via CXCR3/CXCL10 and CCR6/CCL20 pathways, respectively. Taken together, these data confirm the existence of an immunosuppressive gradient across the TME, NTME, and peripheral blood in primary HCC that manipulates the activation status of tumor-infiltrating leukocytes and renders them immunocompromised against tumor cells. By understanding the immunologic composition of this gradient, more effective immunotherapeutics for HCC may be designed.

Metabolic Cooperation and Competition in the Tumor Microenvironment: Implications for Therapy

The tumor microenvironment (TME) is an ensemble of non-tumor cells comprising fibroblasts, cells of the immune system, and endothelial cells, besides various soluble secretory factors from all cellular components (including tumor cells). The TME forms a pro-tumorigenic cocoon around the tumor cells where reprogramming of the metabolism occurs in tumor and non-tumor cells that underlies the nature of interactions as well as competitions ensuring steady supply of nutrients and anapleoretic molecules for the tumor cells that fuels its growth even under hypoxic conditions. This metabolic reprogramming also plays a significant role in suppressing the immune attack on the tumor cells and in resistance to therapies. Thus, the metabolic cooperation and competition among the different TME components besides the inherent alterations in the tumor cells arising out of genetic as well as epigenetic changes supports growth, metastasis, and therapeutic resistance. This review focuses on the metabolic remodeling achieved through an active cooperation and competition among the three principal components of the TME—the tumor cells, the T cells, and the cancer-associated fibroblasts while discussing about the current strategies that target metabolism of TME components. Further, we will also consider the probable therapeutic opportunities targeting the various metabolic pathways as well as the signaling molecules/transcription factors regulating them for the development of novel treatment strategies for cancer.

Regulatory T cells in cancer immunotherapy

FOXP3-expressing regulatory T (Treg) cells, which suppress aberrant immune response against self-antigens, also suppress anti-tumor immune response. Infiltration of a large number of Treg cells into tumor tissues is often associated with poor prognosis. There is accumulating evidence that the removal of Treg cells is able to evoke and enhance anti-tumor immune response. However, systemic depletion of Treg cells may concurrently elicit deleterious autoimmunity. One strategy for evoking effective tumor immunity without autoimmunity is to specifically target terminally differentiated effector Treg cells rather than all FOXP3⁺ T cells, because effector Treg cells are the predominant cell type in tumor tissues. Various cell surface molecules, including chemokine receptors such as CCR4, that are specifically expressed by effector Treg cells can be the candidates for depleting effector Treg cells by specific cell-depleting monoclonal antibodies. In addition, other immunological characteristics of effector Treg cells, such as their high expression of CTLA-4, active proliferation, and apoptosis-prone tendency, can be exploited to control specifically their functions. For example, anti-CTLA-4 antibody may kill effector Treg cells or attenuate their suppressive activity. It is hoped that combination of Treg-cell targeting (e.g., by reducing Treg cells or attenuating their suppressive activity in tumor tissues) with the activation of tumor-specific effector T cells (e.g., by cancer vaccine or immune checkpoint blockade) will make the current cancer immunotherapy more effective.

Chronic NF-κB activation links COPD and lung cancer through generation of an immunosuppressive microenvironment in the lungs

Nuclear Factor (NF)-κB is positioned to provide the interface between COPD and carcinogenesis through regulation of chronic inflammation in the lungs. Using a tetracycline-inducible transgenic mouse model that conditionally expresses activated IκB kinase β (IKKβ) in airway epithelium (IKTA), we found that sustained NF-κB signaling results in chronic inflammation and emphysema by 4 months. By 11 months of transgene activation, IKTA mice develop lung adenomas. Investigation of lung inflammation in IKTA mice revealed a substantial increase in M2-polarized macrophages and CD4+/CD25+/FoxP3+ regulatory T lymphocytes (Tregs). Depletion of alveolar macrophages in IKTA mice reduced Tregs, increased lung CD8+ lymphocytes, and reduced tumor numbers following treatment with the carcinogen urethane. Alveolar macrophages from IKTA mice supported increased generation of inducible Foxp3+ Tregs ex vivo through expression of TGFβ and IL-10. Targeting of TGFβ and IL-10 reduced the ability of alveolar macrophages from IKTA mice to induce Foxp3 expression on T cells. These studies indicate that sustained activation of NF-κB pathway links COPD and lung cancer through generation and maintenance of a pro-tumorigenic inflammatory environment consisting of alternatively activated macrophages and regulatory T cells.

Immune modulation of CD4+CD25+ regulatory T cells by zoledronic acid

Background

CD4⁺CD25⁺ regulatory T (Treg) cells suppress tumor immunity by inhibiting immune cells. Manipulation of Treg cells represents a new strategy for cancer treatment. Zoledronic acid (ZA), a nitrogen-containing bisphosphonate, inhibits the expression of receptor activator of nuclear factor kappa-B ligand (RANKL) on osteoblasts to inhibit osteoclastogenesis. In a mouse model of bisphosphonate-related osteonecrosis of the jaw, administration of ZA suppressed Treg-cell activity and activated inflammatory Th17 cells. However, the interaction between ZA and Treg cells remained unclear. This study investigated the immune modulation of Treg cells by ZA.

Methods

Flow cytometry was used to analyze the phenotypic and immunosuppressive characteristics of Treg cells treated with ZA. Chemotactic migration was evaluated using transwell assays. Quantitative real-time PCR (qRT-PCR) was used to investigate the effect of ZA on the expression of suppressive molecules by Treg cells.

Results

Proliferation of isolated Treg cells in culture was inhibited by ZA, although ZA did not induce apoptosis. qRT-PCR and flow cytometry showed that ZA significantly downregulated the expression of CCR4, CTLA4, PD-1 and RANKL on Treg cells. Chemotactic migration and immunosuppressive functions were also significantly attenuated in Treg cells pretreated with ZA, and these effects were dose-dependent. Co-culture with Treg cells significantly increased the migration rate of breast cancer cells, while pretreatment of Treg cells with ZA attenuated this effect.

Conclusions

Our findings demonstrated that ZA acted as an immune modulator by significantly inhibiting the expansion, migration, immunosuppressive function and pro-metastatic ability of Treg cells. Immunomodulation of Treg cells by ZA represents a new strategy for cancer therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-016-0183-7) contains supplementary material, which is available to authorized users.

Generation of T cell effectors using tumor cell-loaded dendritic cells for adoptive T cell therapy

Adoptive T cell transfer has been shown to be an effective method used to boost tumor-specific immune responses in several types of malignancies. In this study, we set out to optimize the ACT protocol for the experimental treatment of prostate cancer. The protocol includes a pre-stimulation step whereby T cells were primed with autologous dendritic cells loaded with the high hydrostatic pressure-treated prostate cancer cell line, LNCaP. Primed T cells were further expanded in vitro with anti-CD3/CD28 Dynabeads in the WAVE bioreactor 2/10 system and tested for cytotoxicity. Our data indicates that the combination of pre-stimulation and expansion steps resulted in the induction and enrichment of tumor-responsive CD4⁺ and CD8⁺ T cells at clinically relevant numbers. The majority of both CD4⁺ and CD8⁺ IFN-γ producing cells were CD62L, CCR7 and CD57 negative but CD28 and CD27 positive, indicating an early antigen experienced phenotype in non-terminal differentiation phase. Expanded T cells showed significantly greater cytotoxicity against LNCaP cells compared to the control SKOV-3, an ovarian cancer line. In summary, our results suggest that the ACT approach together with LNCaP-loaded dendritic cells provides a viable way to generate prostate cancer reactive T cell effectors that are capable of mounting efficient and targeted antitumor responses and can be thus considered for further testing in a clinical setting.

Circulating and disseminated tumour cells - mechanisms of immune surveillance and escape

Metastatic spread of tumour cells is the main cause of cancer-related deaths. Understanding the mechanisms of tumour-cell dissemination has, therefore, become an important focus for cancer research. In patients with cancer, disseminated cancer cells are often detectable in the peripheral blood as circulating tumour cells (CTCs) and in the bone marrow or lymph nodes as disseminated tumour cells (DTCs). The identification and characterization of CTCs and DTCs has yielded important insights into the mechanisms of metastasis, resulting in a better understanding of the molecular alterations and profiles underlying drug resistance. Given the expanding role of immunotherapies in the treatment of cancer, interactions between tumour cells and immune cells are the subject of intense research. Theoretically, cancer cells that exit the primary tumour site - leaving the protection of the typically immunosuppressive tumour microenvironment - will be more vulnerable to attack by immune effector cells; thus, the survival of tumour cells after dissemination might be the 'Achilles' heel' of metastatic progression. In this Review, we discuss findings relating to the interactions of CTCs and DTCs with the immune system, in the context of cancer immuno-editing, evasion from immune surveillance, and formation of metastases.

Immunobiology of hepatocarcinogenesis: Ways to go or almost there?

Hepatocellular carcinoma is on the rise and occurs in the setting of chronic liver disease and cirrhosis. Though treatment modalities are available, mortality from this cancer remains high. Medical therapy with the utilization of biologic compounds such as the Food and Drug Administration approved sorafenib might be the only option that can increase survival. Immunotherapy, with modern pharmacologic developments, is a new frontier in cancer therapy and therefore the immunobiology of hepatocarcinogenesis is under investigation. This review will discuss current concepts of immunobiology in hepatocarcinogenesis along with current treatment modalities employing immunotherapy. The tumor microenvironment along with a variety of immune cells coexists and interplays to lead to tumorigenesis. Tumor infiltrating lymphocytes including CD8(+) T cells, CD4(+) T cells along with regulatory T cells, tumor associated macrophages, tumor associated neutrophils, myeloid derived suppressor cells, and natural killer cells interact to actively provide anti-tumor or pro-tumor effects. Furthermore, oncogenic pathways such as Raf/mitogen-activated protein kinase/extracellular-signal-regulated kinase pathway, phosphatidyl-3-kinase/AKT/mammalian target or rapamycin, Wnt/β-catenin, nuclear factor-κB and signal transducers and activators of transcription 3 may lead to activation and proliferation of tumor cells and are also considered cornerstones in tumorigenesis. Immunotherapy directed at this complex milieu of cells has been showned to be successful in cancer treatment. The use of vaccines, adoptive cell therapy and immune checkpoint inhibitor modulation are current options for therapy. Further translational research will shed light to concepts such as anti-tumor immunity which can add another alternative in the therapeutic armamentarium.

A Perspective of Immunotherapy for Prostate Cancer

In cancer patients, the immune system is often altered with an excess of inhibitory factors, such as immunosuppressive cytokines, produced by regulatory T cells (Treg) or myeloid-derived suppressor cells (MDSC). The manipulation of the immune system has emerged as one of new promising therapies for cancer treatment, and also represents an attractive strategy to control prostate cancer (PCa). Therapeutic cancer vaccines and immune checkpoint inhibitors have been the most investigated in clinical trials. Many trials are ongoing to define the effects of immune therapy with established treatments: androgen deprivation therapy (ADT) and chemotherapy (CT) or radiotherapy (RT). This article discusses some of these approaches in the context of future treatments for PCa.

Suppression of the noninvolved pair of the myeloma isotype correlates with poor survival in newly diagnosed and relapsed/refractory patients with myeloma

Heavy light chain (HLC) assays allow precise measurement of the monoclonal and of the noninvolved polyclonal immunoglobulins of the same isotype as the M‐protein (e.g., monoclonal IgAκ and polyclonal IgAλ in case of an IgAκ myeloma), which was not possible before. The noninvolved polyclonal immunoglobulin is termed ‘HLC‐matched pair’. We investigated the impact of the suppression of the HLC‐matched pair on outcome in 203 patients with multiple myeloma, a phenomenon that likely reflects the host's attempt to control the myeloma clone. Severe (>50%) HLC‐matched pair suppression was identified in 54.5% of the 156 newly diagnosed patients and was associated with significantly shorter survival (45.4 vs. 71.9 months, P = 0.019). This correlation was statistically significant in IgG patients (46.4 vs. 105.1 months, P = 0.017), but not in patients with IgA myelomas (32.9 vs. 54.1 months, P = 0.498). At best response, HLC‐matched pair suppression improved only in patients with ≥VGPR, indicating partial or complete humoral immune reconstitution during remission in those with excellent response. Severe HLC‐matched pair suppression retained its prognostic impact also during follow‐up after first response. In the 47 pretreated patients with relapsed/refractory disease, a similar correlation between severe HLC suppression and survival was noted (22.8 vs. not reached, P = 0.028). Suppression of the polyclonal immunoglobulins of the other isotypes than the myeloma protein correlated neither with HLC‐matched pair suppression, nor with outcome. Multivariate analysis identified severe HLC‐matched pair suppression as independent risk factor for shorter survival, highlighting the impact of isotype specific immune dysregulation on outcome in multiple myeloma. Am. J. Hematol. 91:295–301, 2016. © 2015 The Authors. American Journal of Hematology Published by Wiley Periodicals, Inc.

T Cells and Cancer: How Metabolism Shapes Immunity

Tumor microenvironment is characterized by a consistent reduction in oxygen and blood-borne nutrients that significantly affects the metabolism of distinct cell subsets. Immune cells populating malignant lesions need to activate alternative pathways to overcome tumor-prolonged nutrient deprivation. In particular, the metabolic switch occurring in transforming tissues dramatically impacts on tumor-infiltrating T cell biology. Remarkably, the recruitment and activation of T cell within cancers are instrumental for effective antitumor response. Therefore, T cell metabolic adaptation acts as crucial checkpoint hijacked by tumors to dampen antitumor immunity.

Translating Treg Therapy in Humanized Mice

Regulatory T cells (Treg) control immune cell function as well as non-immunological processes. Their far-reaching regulatory activities suggest their functional manipulation as a means to sustainably and causally intervene with the course of diseases. Preclinical tools and strategies are however needed to further test and develop interventional strategies outside the human body. “Humanized” mouse models consisting of mice engrafted with human immune cells and tissues provide new tools to analyze human Treg ontogeny, immunobiology, and therapy. Here, we summarize the current state of humanized mouse models as a means to study human Treg function at the molecular level and to design strategies to harness these cells for therapeutic purposes.

Beyond the Immune Suppression: The Immunotherapy in Prostate Cancer

Prostate cancer (PCa) is the second most common cancer in men. As well in many other human cancers, inflammation and immune suppression have an important role in their development. We briefly describe the host components that interact with the tumor to generate an immune suppressive environment involved in PCa promotion and progression. Different tools provide to overcome the mechanisms of immunosuppression including vaccines and immune checkpoint blockades. With regard to this, we report results of most recent clinical trials investigating immunotherapy in metastatic PCa (Sipuleucel-T, ipilimumab, tasquinimod, Prostvac-VF, and GVAX) and provide possible future perspectives combining the immunotherapy to the traditional therapies.

Hyperthermic intraperitoneal chemotherapy leads to an anticancer immune response via exposure of cell surface heat shock protein 90

The occurrence of peritoneal carcinomatosis is a major cause of treatment failure in colorectal cancer and is considered incurable. However, new therapeutic approaches have been proposed, including cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC). Although HIPEC has been effective in selected patients, it is not known how HIPEC prolongs a patient's lifespan. Here, we have demonstrated that HIPEC-treated tumor cells induce the activation of tumor-specific T cells and lead to vaccination against tumor cells in mice. We have established that this effect results from the HIPEC-mediated exposure of heat shock protein (HSP) 90 at the plasma membrane. Inhibition or blocking of HSP90, but not HSP70, prevented the HIPEC-mediated antitumoral vaccination. Our work raises the possibility that the HIPEC procedure not only kills tumor cells but also induces an efficient anticancer immune response, therefore opening new opportunities for cancer treatment.

The changes of angiogenesis and immune cell infiltration in the intra- and peri-tumoral melanoma microenvironment

Malignant melanoma (MM) urgently needs identification of new markers with better predictive value than currently-used clinical and histological parameters. Cancer cells stimulate the formation of a specialized tumor microenvironment, which reciprocally affects uncontrolled proliferation and migration. However, this microenvironment is heterogeneous with different sub-compartments defined by their access to oxygen and nutrients. This study evaluated microvascular density (MVD), CD3+ lymphocytes (TILs) and FOXP3+ T-regulatory lymphocytes (Tregs) on formalin-fixed paraffin-embedded tissue sections using light microscopy. We analyzed 82 malignant melanomas, divided according to the AJCC TNM classification into four groups--pT1 (35), pT2 (17), pT3 (18) and pT4 (12)--and 25 benign pigmented nevi. All parameters were measured in both the central areas of tumors (C) and at their periphery (P). A marked increase in all parameters was found in melanomas compared to nevi (p = 0.0001). There was a positive correlation between MVD, TILs, FOXP3+ Tregs and the vertical growth phase. The results show that MVD, TILs and FOXP3+ Tregs substantially influence cutaneous melanoma microenvironment. We found significant topographic differences of the parameters between central areas of tumors and their boundaries.

Interleukin-5 facilitates lung metastasis by modulating the immune microenvironment

Although the lung is the most common metastatic site for cancer cells, biologic mechanisms regulating lung metastasis are not fully understood. Using heterotopic and intravenous injection models of lung metastasis in mice, we found that IL5, a cytokine involved in allergic and infectious diseases, facilitates metastatic colonization through recruitment of sentinel eosinophils and regulation of other inflammatory/immune cells in the microenvironment of the distal lung. Genetic IL5 deficiency offered marked protection of the lungs from metastasis of different types of tumor cells, including lung cancer, melanoma, and colon cancer. IL5 neutralization protected subjects from metastasis, whereas IL5 reconstitution or adoptive transfer of eosinophils into IL5-deficient mice exerted prometastatic effects. However, IL5 deficiency did not affect the growth of the primary tumor or the size of metastatic lesions. Mechanistic investigations revealed that eosinophils produce CCL22, which recruits regulatory T cells to the lungs. During early stages of metastasis, Treg created a protumorigenic microenvironment, potentially by suppressing IFNγ-producing natural killer cells and M1-polarized macrophages. Together, our results establish a network of allergic inflammatory circuitry that can be co-opted by metastatic cancer cells to facilitate lung colonization, suggesting interventions to target this pathway may offer therapeutic benefits to prevent or treat lung metastasis.

Regulatory T cells are not a strong predictor of survival for patients with glioblastoma

BACKGROUND

Regulatory T cells (Tregs) are potentially prognostic indicators in patients with glioblastoma. If differences in frequency of Tregs in tumor or blood account for substantial variation in patient survival, then reliably measuring Tregs may enhance treatment selection and improve outcomes.

METHODS

We measured Tregs and CD3+ T cells in tumors and blood from 25 patients with newly diagnosed glioblastoma. Tumor-infiltrating Tregs and CD3+ T cells, measured by quantitative DNA demethylation analysis (epigenetic qPCR) and by immunohistochemistry, and peripheral blood Treg proportions measured by flow cytometry were correlated with patient survival. Additionally, we analyzed data from The Cancer Genome Atlas (TCGA) to correlate the expression of Treg markers with patient survival and glioblastoma subtypes.

RESULTS

Tregs, as measured in tumor tissue and peripheral blood, did not correlate with patient survival. Although there was a correlation between tumor-infiltrating Tregs expression by epigenetic qPCR and immunohistochemistry, epigenetic qPCR was more sensitive and specific. Using data from TCGA, mRNA expression of Forkhead box protein 3 (FoxP3) and Helios and FoxP3 methylation level did not predict survival. While the classical glioblastoma subtype corresponded to lower expression of Treg markers, these markers did not predict survival in any of the glioblastoma subtypes.

CONCLUSIONS

Although immunosuppression is a hallmark of glioblastoma, Tregs as measured in tissue by gene expression, immunohistochemistry, or demethylation and Tregs in peripheral blood measured by flow cytometry do not predict survival of patients. Quantitative DNA demethylation analysis provides an objective, sensitive, and specific way of identifying Tregs and CD3+ T cells in glioblastoma.

Pathologic and imunohistochemical characterization of tumoral inflammatory cell infiltrate in invasive penile squamous cell carcinomas: Fox-P3 expression is an independent predictor of recurrence

Penile carcinomas (PeCa) are relatively rare, but devastating neoplasms, more frequent among people of underprivileged socioeconomic status. There is mounting evidence that immune cells may trigger various mechanisms that enhance tumor growth and metastasis, but no data on the peritumoral inflammation is available for PeCa. The objectives of the present study are to evaluate the immunohistomorphology of tumoral inflammation in PeCa, and to correlate it with clinicopathological parameters, which could contribute to the prognostic evaluation. One hundred and twenty-two patients with the diagnosis of usual-type squamous cell penile carcinoma were included. Paraffin-embedded tissue was submitted to immunohistochemical evaluation of p16 protein, CD3, CD4, CD8, CD20, CD68, CD138, granzyme B, and Fox-P3. The Fisher's exact test was employed for comparison between histological variables and parameters, and the Kaplan-Meier method for the analysis of survival. Improved 5-year overall survival was significantly associated to age ≤60 years, stage I + II, tumor size T1 + T2, lymph node status N0, and absent perineural invasion. In a multivariate analysis age ≥60 years, presence of lymph node metastasis, urethral invasion, and high histologic grade retained a significantly more unfavorable outcome. Improved 5-year failure free survival was associated to stage of the disease I + II, lymph node status N0, absence of perineural, vascular, and urethral invasion, and Fox-P3 expression. In a multivariate analysis, presence of lymph node metastasis, perineural and vascular invasion, and of Fox-P3-positive lymphocytes together with low inflammatory infiltrate retained a significantly more unfavorable outcome. These results support the prognostic value of determining the levels of Fox-P3-positive lymphocytes by immunohistochemistry in PeCa, as this parameter adds value to the traditional clinicopathological features.

The bone marrow of myeloma patients is steadily inhabited by a normal-sized pool of functional regulatory T cells irrespectiveof the disease status

Conflicting data have been reported about the frequency and function of regulatory T cells in multiple myeloma. Most studies have investigated peripheral blood rather than bone marrow Tregs and side-by-side comparisons with bone marrow from healthy donors have still not been made. In this study, we show that regulatory T-cells total count, subset distribution, and expression of chemokine receptors are similar in the bone marrow of myeloma patients and healthy donors. Regulatory T cells are not recruited by myeloma cells in the bone marrow and their counts are unaffected by the tumor burden and the disease status. The diversity of T-cell receptor repertoire is highly preserved ensuring broad reactivity and effective suppressor function. Our results indicate that regulatory T cells may not be the main players of immunological tolerance to myeloma cells under base-line conditions, but their fully preserved immune competence may promote their inadvertent activation and blunt T-cell driven anti-myeloma immune interventions even after myeloma cells have successfully been cleared by chemotherapy.

Gut microbiota and the paradox of cancer immunotherapy

It is recently shown that beneficial environmental microbes stimulate integrated immune and neuroendocrine factors throughout the body, consequently modulating regulatory T-lymphocyte phenotypes, maintaining systemic immune balance, and determining the fate of preneoplastic lesions toward regression while sustaining whole body good health. Stimulated by a gut microbiota-centric systemic homeostasis hypothesis, we set out to explore the influence of the gut microbiome to explain the paradoxical roles of regulatory T-lymphocytes in cancer development and growth. This paradigm shift places cancer prevention and treatment into a new broader context of holobiont engineering to cultivate a tumor-suppressive macroenvironment.

Urokinase-type plasminogen activator deficiency promotes neoplasmatogenesis in the colon of mice

Urokinase-type plasminogen activator (uPA) participates in cancer-related biologic processes, such as wound healing and inflammation. The present study aimed to investigate the effect of uPA deficiency on the long-term outcome of early life episodes of dextran sodium sulfate (DSS)-induced colitis in mice. Wild-type (WT) and uPA-deficient (uPA(-/-)) BALB/c mice were treated with DSS or remained untreated. Mice were necropsied either 1 week or 7 months after DSS treatment. Colon samples were analyzed by histopathology, immunohistochemistry, ELISA, and real-time polymerase chain reaction. At 7 months, with no colitis evident, half of the uPA(-/-) mice had large colonic polypoid adenomas, whereas WT mice did not. One week after DSS treatment, there were typical DSS-induced colitis lesions in both WT and uPA(-/-) mice. The affected colon of uPA(-/-) mice, however, had features of delayed ulcer re-epithelialization and dysplastic lesions of higher grade developing on the basis of a significantly altered mucosal inflammatory milieu. The later was characterized by more neutrophils and macrophages, less regulatory T cells (Treg), significantly upregulated cytokines, including interleukin-6 (IL-6), IL-17, tumor necrosis factor-α, and IL-10, and lower levels of active transforming growth factor-β1 (TGF-β1) compared to WT mice. Dysfunctional Treg, more robust protumorigenic inflammatory events, and an inherited inability to produce adequate amounts of extracellular active TGF-β1 due to uPA deficiency are interlinked as probable explanations for the inflammatory-induced neoplasmatogenesis in the colon of uPA(-/-) mice.

Intermittent hypoxia-induced changes in tumor-associated macrophages and tumor malignancy in a mouse model of sleep apnea

RATIONALE

An increased cancer aggressiveness and mortality have been recently reported among patients with obstructive sleep apnea (OSA). Intermittent hypoxia (IH), a hallmark of OSA, enhances melanoma growth and metastasis in mice.

OBJECTIVES

To assess whether OSA-related adverse cancer outcomes occur via IH-induced changes in host immune responses, namely tumor-associated macrophages (TAMs).

MEASUREMENTS AND MAIN RESULTS

Lung epithelial TC1 cell tumors were 84% greater in mice subjected to IH for 28 days compared with room air (RA). In addition, TAMs in IH-exposed tumors exhibited reductions in M1 polarity with a shift toward M2 protumoral phenotype. Although TAMs from tumors harvested from RA-exposed mice increased TC1 migration and extravasation, TAMs from IH-exposed mice markedly enhanced such effects and also promoted proliferative rates and invasiveness of TC1 cells. Proliferative rates of melanoma (B16F10) and TC1 cells exposed to IH either in single culture or in coculture with macrophages (RAW 264.7) increased only when RAW 264.7 macrophages were concurrently present.

CONCLUSIONS

Our findings support the notion that IH-induced alterations in TAMs participate in the adverse cancer outcomes reported in OSA.

Natural and induced T regulatory cells in cancer

CD4+Foxp3+ T regulatory (Treg) cells control many facets of immune responses ranging from autoimmune diseases, to inflammatory conditions, and cancer in an attempt to maintain immune homeostasis. Natural Treg (nTreg) cells develop in the thymus and constitute a critical arm of active mechanisms of peripheral tolerance particularly to self antigens. A growing body of knowledge now supports the existence of induced Treg (iTreg) cells which may derive from a population of conventional CD4+ T cells. The fork-head transcription factor (Foxp3) typically is expressed by natural CD4+ Treg cells, and thus serves as a marker to definitively identify these cells. On the contrary, there is less consensus on what constitutes iTreg cells as their precise definition has been somewhat elusive. This is in part due to their distinct phenotypes which are shaped by exposure to certain inflammatory or "assault" signals stemming from the underlying immune disorder. The "policing" activity of Treg cells tends to be uni-directional in several pathological conditions. On one end of the spectrum, Treg cell suppressive activity is beneficial by curtailing T cell response against self-antigens and allergens thus preventing autoimmune diseases and allergies. On the other end however, their inhibitory roles in limiting immune response against pseudo-self antigens as in tumors often culminates into negative outcomes. In this review, we focus on this latter aspect of Treg cell immunobiology by highlighting the involvement of nTreg cells in various animal models and human tumors. We further discuss iTreg cells, relationship with their natural counterpart, and potential co-operation between the two in modulating immune response against tumors. Lastly, we discuss studies focusing on these cells as targets for improving anti-tumor immunity.

Natural and induced T regulatory cells in cancer

CD4+Foxp3+ T regulatory (Treg) cells control many facets of immune responses ranging from autoimmune diseases, to inflammatory conditions, and cancer in an attempt to maintain immune homeostasis. Natural Treg (nTreg) cells develop in the thymus and constitute a critical arm of active mechanisms of peripheral tolerance particularly to self antigens. A growing body of knowledge now supports the existence of induced Treg (iTreg) cells which may derive from a population of conventional CD4+ T cells. The fork-head transcription factor (Foxp3) typically is expressed by natural CD4+ Treg cells, and thus serves as a marker to definitively identify these cells. On the contrary, there is less consensus on what constitutes iTreg cells as their precise definition has been somewhat elusive. This is in part due to their distinct phenotypes which are shaped by exposure to certain inflammatory or “assault” signals stemming from the underlying immune disorder. The “policing” activity of Treg cells tends to be uni-directional in several pathological conditions. On one end of the spectrum, Treg cell suppressive activity is beneficial by curtailing T cell response against self-antigens and allergens thus preventing autoimmune diseases and allergies. On the other end however, their inhibitory roles in limiting immune response against pseudo-self antigens as in tumors often culminates into negative outcomes. In this review, we focus on this latter aspect of Treg cell immunobiology by highlighting the involvement of nTreg cells in various animal models and human tumors. We further discuss iTreg cells, relationship with their natural counterpart, and potential co-operation between the two in modulating immune response against tumors. Lastly, we discuss studies focusing on these cells as targets for improving anti-tumor immunity.

Update on the challenges and recent advances in cancer immunotherapy

This overview provides an analysis of some of the immunotherapies currently in use and under investigation, with a special focus on the tumor microenvironment, which we believe is a major factor responsible for the general failure of immunotherapy to date. It is our expectation that combining immunotherapy with methods of altering the tumor microenvironment and targeting regulatory T cells and myeloid cells will yield favorable results.

Interleukin-21 (IL-21) synergizes with IL-2 to enhance T-cell receptor-induced human T-cell proliferation and counteracts IL-2/transforming growth factor-β-induced regulatory T-cell development

Interleukin-2 (IL-2) is a mainstay for current immunotherapeutic protocols but its usefulness in patients is reduced by severe toxicities and because IL-2 facilitates regulatory T (Treg) cell development. IL-21 is a type I cytokine acting as a potent T-cell co-mitogen but less efficient than IL-2 in sustaining T-cell proliferation. Using various in vitro models for T-cell receptor (TCR)-dependent human T-cell proliferation, we found that IL-21 synergized with IL-2 to make CD4(+) and CD8(+) T cells attain a level of expansion that was impossible to obtain with IL-2 alone. Synergy was mostly evident in naive CD4(+) cells. IL-2 and tumour-released transforming growth factor-β (TGF-β) are the main environmental cues that cooperate in Treg cell induction in tumour patients. Interleukin-21 hampered Treg cell expansion induced by IL-2/TGF-β combination in naive CD4(+) cells by facilitating non-Treg over Treg cell proliferation from the early phases of cell activation. Conversely, IL-21 did not modulate the conversion of naive activated CD4(+) cells into Treg cells in the absence of cell division. Treg cell reduction was related to persistent activation of Stat3, a negative regulator of Treg cells associated with down-modulation of IL-2/TGF-β-induced phosphorylation of Smad2/3, a positive regulator of Treg cells. In contrast to previous studies, IL-21 was completely ineffective in counteracting the suppressive activity of Treg cells on naive and memory, CD4(+) and CD8(+) T cells. Present data provide proof-of-concept for evaluating a combinatorial approach that would reduce the IL-2 needed to sustain T-cell proliferation efficiently, thereby reducing toxicity and controlling a tolerizing mechanism responsible for the contraction of the T-cell response.

Expanding roles for CD4 T cells and their subpopulations in tumor immunity and therapy

The importance of CD4 T cells in orchestrating the immune system and their role in inducing effective T cell-mediated therapies for the treatment of patients with select established malignancies are undisputable. Through a complex and balanced array of direct and indirect mechanisms of cellular activation and regulation, this functionally diverse family of lymphocytes can potentially promote tumor eradication, long-term tumor immunity, and aid in establishing and/or rebalancing immune cell homeostasis through interaction with other immune cell populations within the highly dynamic tumor environment. However, recent studies have uncovered additional functions and roles for CD4 T cells, some of which are independent of other lymphocytes, that can not only influence and contribute to tumor immunity but paradoxically promote tumor growth and progression. Here, we review the recent advances in our understanding of the various CD4 T cell lineages and their signature cytokines in disease progression and/or regression. We discuss their direct and indirect mechanistic interplay among themselves and with other responding cells of the antitumor response, their potential roles and abilities for "plasticity" and memory cell generation within the hostile tumor environment, and their potentials in cancer treatment and immunotherapy.