Regulatory T Cells and Cancer: A Two-Sided Story

A Vaccine against Cancer: Can There Be a Possible Strategy to Face the Challenge? Possible Targets and Paradoxical Effects

Is it possible to have an available vaccine that eradicates cancer? Starting from this question, this article tries to verify the state of the art, proposing a different approach to the issue. The variety of cancers and different and often unknown causes of cancer impede, except in some cited cases, the creation of a classical vaccine directed at the causative agent. The efforts of the scientific community are oriented toward stimulating the immune systems of patients, thereby preventing immune evasion, and heightening chemotherapeutic agents effects against cancer. However, the results are not decisive, because without any warning signs, metastasis often occurs. The purpose of this paper is to elaborate on a vaccine that must be administered to a patient in order to prevent metastasis; metastasis is an event that leads to death, and thus, preventing it could transform cancer into a chronic disease. We underline the fact that the field has not been studied in depth, and that the complexity of metastatic processes should not be underestimated. Then, with the aim of identifying the target of a cancer vaccine, we draw attention to the presence of the paradoxical actions of different mechanisms, pathways, molecules, and immune and non-immune cells characteristic of the tumor microenvironment at the primary site and pre-metastatic niche in order to exclude possible vaccine candidates that have opposite effects/behaviors; after a meticulous evaluation, we propose possible targets to develop a metastasis-targeting vaccine. We conclude that a change in the current concept of a cancer vaccine is needed, and the efforts of the scientific community should be redirected toward a metastasis-targeting vaccine, with the increasing hope of eradicating cancer.

Cell-Based Drug Delivery Systems Participate in the Cancer Immunity Cycle for Improved Cancer Immunotherapy

Immunotherapy aims to activate the cancer patient's immune system for cancer therapy. The whole process of the immune system against cancer referred to as the "cancer immunity cycle", gives insight into how drugs can be designed to affect every step of the anticancer immune response. Cancer immunotherapy such as immune checkpoint inhibitor (ICI) therapy, cancer vaccines, as well as small molecule modulators has been applied to fight various cancers. However, the effect of immunotherapy in clinical applications is still unsatisfactory due to the limited response rate and immune-related adverse events. Mounting evidence suggests that cell-based drug delivery systems (DDSs) with low immunogenicity, superior targeting, and prolonged circulation have great potential to improve the efficacy of cancer immunotherapy. Therefore, with the rapid development of cell-based DDSs, understanding their important roles in various stages of the cancer immunity cycle guides the better design of cell-based cancer immunotherapy. Herein, an overview of how cell-based DDSs participate in cancer immunotherapy at various stages is presented and an outlook on possible challenges of clinical translation and application in future development.

Investigating key cell types and molecules dynamics in PyMT mice model of breast cancer through a mathematical model

The most common kind of cancer among women is breast cancer. Understanding the tumor microenvironment and the interactions between individual cells and cytokines assists us in arriving at more effective treatments. Here, we develop a data-driven mathematical model to investigate the dynamics of key cell types and cytokines involved in breast cancer development. We use time-course gene expression profiles of a mouse model to estimate the relative abundance of cells and cytokines. We then employ a least-squares optimization method to evaluate the model’s parameters based on the mice data. The resulting dynamics of the cells and cytokines obtained from the optimal set of parameters exhibit a decent agreement between the data and predictions. We perform a sensitivity analysis to identify the crucial parameters of the model and then perform a local bifurcation on them. The results reveal a strong connection between adipocytes, IL6, and the cancer population, suggesting them as potential targets for therapies.

One of the outstanding challenges of the mathematical modeling of cancer progression is the existence of many unknown parameters. In this work, we develop a data-driven mathematical model of breast cancer progression by deriving a system of ordinary differential equations for the interaction networks of key cell types and molecules in breast tumors. To overcome the limitations of unknown parameters, we utilize a time course data of a PyMT mice model of breast cancer and estimate parameters using an optimization method. Although the predicted dynamics of cancer and necrotic cells using the obtained values of parameters are in good agreement with the data, the predicted values for a few other variables do not match the data. This might indicate that there are some other key interactions that have not been modeled, and/or there is a noise in the data. The sensitivity and bifurcation analyses show that the most important parameters in controlling the cancer cells population are the proliferation and death rates of cancer cells and adipocytes. These results are in agreement with some biological and clinical studies of breast cancer, which have reported a link between adipocytes and breast cancer progression.

A Mathematical Model of Breast Tumor Progression Based on Immune Infiltration

Breast cancer is the most prominent type of cancer among women. Understanding the microenvironment of breast cancer and the interactions between cells and cytokines will lead to better treatment approaches for patients. In this study, we developed a data-driven mathematical model to investigate the dynamics of key cells and cytokines involved in breast cancer development. We used gene expression profiles of tumors to estimate the relative abundance of each immune cell and group patients based on their immune patterns. Dynamical results show the complex interplay between cells and molecules, and sensitivity analysis emphasizes the direct effects of macrophages and adipocytes on cancer cell growth. In addition, we observed the dual effect of IFN-γ on cancer proliferation, either through direct inhibition of cancer cells or by increasing the cytotoxicity of CD8+ T-cells.

Regulatory T-Cells and Multiple Myeloma: Implications in Tumor Immune Biology and Treatment

Multiple myeloma (MM) is associated with both cellular and humoral immune deficiencies and, despite significant advances in treatment, remains an incurable disease. Regulatory T-cells (Tregs) represent a critical subset of CD4 T-cells, characterized by CD4 + CD25+ Forkhead box P3+ (FoxP3+) phenotype, able to control peripheral tolerance and responses to foreign and tumor antigens. Tregs are elevated in various types of cancer, including hematological malignancies; in MM, data regarding Tregs function and numbers and their correlation with survival parameters are controversial. Advances in cancer biology have shown that the tumor microenvironment plays an important role in tumor progression. In MM, the highly immunosuppressive nature of the bone marrow microenvironment has been significantly elucidated in the past decade and it is now well acknowledged that targeting only the tumor clone may not be able to cure MM. Tregs within the tumor microenvironment might play a significant role in the suppression of antitumor immune responses against cancer cells and are considered to predict poor outcome in cancer patients; nonetheless the exact prognostic significance of this cell subpopulation in malignancies is still a matter of debate. In this review, we discuss the role of Tregs as an essential cell population of the MM immune microenvironment.

Investigating Optimal Chemotherapy Options for Osteosarcoma Patients through a Mathematical Model

Simple Summary

Osteosarcoma is a rare type of cancer with poor prognoses. However, to the best of our knowledge, there are no mathematical models that study the impact of chemotherapy treatments on the osteosarcoma microenvironment. In this study, we developed a data driven mathematical model to analyze the dynamics of the important players in three groups of osteosarcoma tumors with distinct immune patterns in the presence of the most common chemotherapy drugs. The results indicate that the treatments’ start times and optimal dosages depend on the unique growth rate of the tumor, which implies the necessity of personalized medicine. Furthermore, the developed model can be extended by others to build models that can recommend individual-specific optimal dosages.

Abstract

Since all tumors are unique, they may respond differently to the same treatments. Therefore, it is necessary to study their characteristics individually to find their best treatment options. We built a mathematical model for the interactions between the most common chemotherapy drugs and the osteosarcoma microenvironments of three clusters of tumors with unique immune profiles. We then investigated the effects of chemotherapy with different treatment regimens and various treatment start times on the behaviors of immune and cancer cells in each cluster. Saliently, we suggest the optimal drug dosages for the tumors in each cluster. The results show that abundances of dendritic cells and HMGB1 increase when drugs are given and decrease when drugs are absent. Populations of helper T cells, cytotoxic cells, and IFN-γ grow, and populations of cancer cells and other immune cells shrink during treatment. According to the model, the MAP regimen does a good job at killing cancer, and is more effective than doxorubicin and cisplatin combined or methotrexate alone. The results also indicate that it is important to consider the tumor’s unique growth rate when deciding the treatment details, as fast growing tumors need early treatment start times and high dosages.

Data Driven Mathematical Model of FOLFIRI Treatment for Colon Cancer

Many colon cancer patients show resistance to their treatments. Therefore, it is important to consider unique characteristic of each tumor to find the best treatment options for each patient. In this study, we develop a data driven mathematical model for interaction between the tumor microenvironment and FOLFIRI drug agents in colon cancer. Patients are divided into five distinct clusters based on their estimated immune cell fractions obtained from their primary tumors' gene expression data. We then analyze the effects of drugs on cancer cells and immune cells in each group, and we observe different responses to the FOLFIRI drugs between patients in different immune groups. For instance, patients in cluster 3 with the highest T-reg/T-helper ratio respond better to the FOLFIRI treatment, while patients in cluster 2 with the lowest T-reg/T-helper ratio resist the treatment. Moreover, we use ROC curve to validate the model using the tumor status of the patients at their follow up, and the model predicts well for the earlier follow up days.

Using dynamic cell communication improves treatment strategies of breast cancer

Several insights from the clinical treatment of breast cancer patients have revealed that only a portion of patients achieve the expected curative effect after traditional targeted therapy, that surgical treatment may promote the development of cancer metastasis, and that the optimal combination of neoadjuvant chemotherapy and traditional treatment is not clear. Therefore, a more precise classification of breast cancer and selection of treatment methods should be undertaken to improve the efficacy of clinical treatment. In the clinical treatment of breast cancer, cell communication molecules are often selected as therapeutic targets. However, various cell communications are not static. Their dynamic changes are related to communicating cells, communicating molecules, and various intertwined internal and external environmental factors. Understanding the dynamic microenvironment can help us improve therapeutic efficacy and provide new ways to more accurately determine the cancer status. Therefore, this review describes multiple types of cellular communication in the breast cancer microenvironment and incorporates internal and external environmental factors as variable signaling factors in cell communication. Using dynamic and developmental concepts, we summarize the functional changes in signaling molecules and cells to aid in the diagnosis and treatment of breast cancer.

Data-Driven Mathematical Model of Osteosarcoma

As the immune system has a significant role in tumor progression, in this paper, we develop a data-driven mathematical model to study the interactions between immune cells and the osteosarcoma microenvironment. Osteosarcoma tumors are divided into three clusters based on their relative abundance of immune cells as estimated from their gene expression profiles. We then analyze the tumor progression and effects of the immune system on cancer growth in each cluster. Cluster 3, which had approximately the same number of naive and M2 macrophages, had the slowest tumor growth, and cluster 2, with the highest population of naive macrophages, had the highest cancer population at the steady states. We also found that the fastest growth of cancer occurred when the anti-tumor immune cells and cytokines, including dendritic cells, helper T cells, cytotoxic cells, and IFN-γ, switched from increasing to decreasing, while the dynamics of regulatory T cells switched from decreasing to increasing. Importantly, the most impactful immune parameters on the number of cancer and total cells were the activation and decay rates of the macrophages and regulatory T cells for all clusters. This work presents the first osteosarcoma progression model, which can be later extended to investigate the effectiveness of various osteosarcoma treatments.

Immune classification of osteosarcoma

Tumor immune microenvironment has been shown to be important in predicting the tumor progression and the outcome of treatments. This work aims to identify different immune patterns in osteosarcoma and their clinical characteristics. We use the latest and best performing deconvolution method, CIBERSORTx, to obtain the relative abundance of 22 immune cells. Then we cluster patients based on their estimated immune abundance and study the characteristics of these clusters, along with the relationship between immune infiltration and outcome of patients. We find that abundance of CD8 T cells, NK cells and M1 Macrophages have a positive association with prognosis, while abundance of γδ T cells, Mast cells, M0 Macrophages and Dendritic cells have a negative association with prognosis. Accordingly, the cluster with the lowest proportion of CD8 T cells, M1 Macrophages and highest proportion of M0 Macrophages has the worst outcome among clusters. By grouping patients with similar immune patterns, we are also able to suggest treatments that are specific to the tumor microenvironment.

Data Driven Mathematical Model of Colon Cancer Progression

Every colon cancer has its own unique characteristics, and therefore may respond differently to identical treatments. Here, we develop a data driven mathematical model for the interaction network of key components of immune microenvironment in colon cancer. We estimate the relative abundance of each immune cell from gene expression profiles of tumors, and group patients based on their immune patterns. Then we compare the tumor sensitivity and progression in each of these groups of patients, and observe differences in the patterns of tumor growth between the groups. For instance, in tumors with a smaller density of naive macrophages than activated macrophages, a higher activation rate of macrophages leads to an increase in cancer cell density, demonstrating a negative effect of macrophages. Other tumors however, exhibit an opposite trend, showing a positive effect of macrophages in controlling tumor size. Although the results indicate that for all patients the size of the tumor is sensitive to the parameters related to macrophages, such as their activation and death rate, this research demonstrates that no single biomarker could predict the dynamics of tumors.

Expression of Foxp3 and interleukin-7 receptor and clinicopathological characteristics of patients with diffuse large B-cell lymphoma

The most specific biomarker on the surface of regulatory T cells (Tregs) is the forkhead/wingeded-helix protein 3 (Foxp3). In contrast, the expression of interleukin-7 receptor (IL-7R) is low or negative in Tregs. The present study aimed to investigate the expression of Foxp3 and IL-7R in diffuse large B-cell lymphoma (DLBCL), and to analyse the clinicopathological characteristics of patients with DLBCL and their association with overall survival (OS). Immunohistochemistry was performed to detect the expression of Foxp3 and IL-7R on routinely processed formalin-fixed and paraffin-embedded specimens. The χ² test was used to analyse the association between the expression of Foxp3 and IL-7R and the clinicopathological characteristics of patients with DLBCL. Survival curves were used to investigate the effect of Foxp3 and IL-7R on patient prognosis. The results demonstrated that high Foxp3 expression in tissue was associated with non- germinal centre B-cell (GCB)-type disease (P=0.012), International Prognostic Index score >0 (P=0.012), stage 3 or 4 tumour (P=0.045) and disease progression and stabilization period (P=0.032). In addition, IL-7R expression was associated with non-GCB-type disease (P=0.001) and extranodal lymphoma (P=0.008). Furthermore, expression of Foxp3 and IL-7R was not associated with OS (P=0.447 and P=0.201, respectively). Foxp3 and IL-7R expression in non-GCB-type lymphoma was significantly higher compared with that in GCB lymphoma. The expression of Foxp3 and IL-7R may therefore help the development of individualized treatment, prognostic prediction and therapy stratification.

IL-17 inhibits CXCL9/10-mediated recruitment of CD8+ cytotoxic T cells and regulatory T cells to colorectal tumors

BACKGROUND

The IL-17 family cytokines are potent drivers of colorectal cancer (CRC) development. We and others have shown that IL-17 mainly signals to tumor cells to promote CRC, but the underlying mechanism remains unclear. IL-17 also dampens Th1-armed anti-tumor immunity, in part by attracting myeloid cells to tumor. Whether IL-17 controls the activity of adaptive immune cells in a more direct manner, however, is unknown.

METHODS

Using mouse models of sporadic or inducible colorectal cancers, we ablated IL-17RA in the whole body or specifically in colorectal tumor cells. We also performed adoptive bone marrow reconstitution to knockout CXCR3 in hematopoietic cells. Histological and immunological experimental methods were used to reveal the link among IL-17, chemokine production, and CRC development.

RESULTS

Loss of IL-17 signaling in mouse CRC resulted in marked increase in the recruitment of CD8+ cytotoxic T lymphocytes (CTLs) and regulatory T cells (Tregs), starting from early stage CRC lesions. This is accompanied by the increased expression of anti-inflammatory cytokines IL-10 and TGF-β. IL-17 signaling also inhibits the production of T cell attracting chemokines CXCL9 and CXCL10 by tumor cells. Conversely, the inability of hematopoietic cells to respond to CXCL9/10 resulted in decreased tumor infiltration by CTLs and Tregs, decreased levels of IL-10 and TGF-β, and increased numbers of tumor lesions. Blockade of IL-17 signaling resulted in increased expression of immune checkpoint markers. On the other hand, treatment of mouse CRC with anti-CTLA-4 antibody led to increased expression of pro-tumor IL-17.

CONCLUSION

IL-17 signals to colorectal tumor cells and inhibits their production of CXCL9/10 chemokines. By doing so, IL-17 inhibits the infiltration of CD8+ CTLs and Tregs to CRC, thus promoting CRC development. Cancer immunotherapy may be benefited by the use of anti-IL-17 agents as adjuvant therapies, which serve to block both IL-17-mediated tumor promotion and T cell exclusion.

High Expression of Angiopoietin-like Protein 4 in Advanced Colorectal Cancer and its Association with Regulatory T Cells and M2 Macrophages

Colorectal cancer (CRC) is one of the most aggressive tumours in the human digestive system. Most CRC patients have poor prognosis due to metastasis and recurrence. Angiopoietin-like 4 (ANGPTL4) is involved in tumour development. Regulatory T (Treg) cells and M2 macrophages promote tumour growth and metastasis. Herein, we explored the changes of ANGPTL4 expression in CRC patients at different stages and observed whether in situ tumour-Treg and -M2 macrophages are correlated with ANGPTL4 expression. Serum ANGPTL4 (sANGPTL4) levels of 70 CRC patients and 10 healthy controls were detected by ELISA. ANGPTL4, Foxp3 and CD163 expression levels in CRC tissues were measured by immunohistochemistry. Recombinant ANGPTL4 (rANGPTL4) proteins were further added into cell-culture systems for induction of Treg cells and M2 macrophages. The results showed both sANGPTL4 and in situ tumour-ANGPTL4 expression levels increased in Dukes C-D stage CRC patients. Foxp3⁺ and CD163⁺ cells in tumour tissue sections were also more intensive in Dukes C-D stage patients than in Dukes A-B stage patients. Foxp3⁺ and CD163⁺ cells in tumour tissues were positively correlated with both tissue and sANGPTL4 expression (P < 0.01). Recombinant ANGPTL4 promoted the induction of murine Treg cells and M2 macrophages ex vivo. Therefore, elevated ANGPTL4 expression could be a marker for advanced CRC. Treg cell and M2 macrophage induction could be one of the mechanisms of tumour promotion mediated by ANGPTL4.

Novel TCR-based biologics: mobilising T cells to warm 'cold' tumours

Immunotherapeutic strategies have revolutionised cancer therapy in recent years, bringing meaningful improvements in outcomes for patients with previously intractable conditions. These successes have, however, been largely limited to certain types of liquid tumours and a small subset of solid tumours that are known to be particularly immunogenic. Broadening these advances across the majority of tumour indications, which are characterised by an immune-excluded, immune-deserted or immune-suppressed ('cold') phenotype, will require alternative approaches that are able to specifically address this unique biological environment. Several newer therapeutic modalities, including adoptive cell therapy and T cell redirecting bispecific molecules, are considered to hold particular promise and are being investigated in early phase clinical trials across various solid tumour indications. ImmTAC molecules are a novel class of T cell redirecting bispecific biologics that exploit TCR-based targeting of tumour cells; providing potent and highly specific access to the vast landscape of intracellular targets. The first of these reagents to reach the clinic, tebentafusp (IMCgp100), has generated demonstrable clinical efficacy in an immunologically cold solid tumour with a high unmet need. Here, we highlight the key elements of the ImmTAC platform that make it ideally positioned to overcome the cold tumour microenvironment in an off-the-shelf format.

CD4+CD25highCD127low/-FoxP3 + Regulatory T-Cell Population in Acute Leukemias: A Review of the Literature

Regulatory T-cells (Tregs) are a very important subtype of lymphocytes when it comes to self-control in the human immunological system. Tregs are decisive not only in the protection against destruction of own tissues by autoimmune immunocompetent cells but also in the immunological answer to developing cancers. On the other hand, Tregs could be responsible for the progression of acute and chronic leukemias. In our study, we review publications available in the PUMED database concerning acute leukemia, with a particular emphasis on child's leukemias. The percentage of regulatory T-lymphocytes in peripheral blood and bone marrow was elevated compared to those in healthy individuals and correlated with progressive disease. Regulatory T-cells taken from children diagnosed with leukemia showed a higher suppressive capability, which was confirmed by detecting elevated levels of secreted IL-10 and TGF-beta. The possibility of pharmacological intervention in the self-control of the immunological system is now under extensive investigation in many human cancers. Presumably, Treg cells could be a vital part of targeted therapies. Routine Treg determination could be used to assess the severity of disease and prognosis in children with acute lymphoblastic leukemia. This proposition results from the fact that in some studies, higher percentage of Treg cells in peripheral blood was demonstrated. However, observations confirming these facts are scarce; thus, extrapolating them to the population of children with hematological malignancies needs to be verified in additional studies.

Serum IL-6 and IL-8 Correlate with Prognostic Factors in Ovarian Cancer

The aim of the study was to correlate serum levels of IL-2, IL-5, IL-6, IL-8, IL-10, and TNF-α with clinical, laboratory, and pathological prognostic factors in patients with primary ovarian malignancy. Patients treated at the Pelvic Mass Ambulatory of the Discipline of Gynecology and Obstetrics/Oncology Research Institute (IPON) of the UFTM with confirmed diagnosis of malignant ovarian neoplasia (n = 26) were evaluated. Serum collection was performed preoperatively for the determination of tumor markers. The cytokines IL-2, IL-5, IL-6, IL-8, IL-10, and TNF-α were assayed by enzyme-linked immunosorbent assay (ELISA). The prognostic factors were compared using the Mann-Whitney test, with significance level lower than 0.05. When evaluating IL6, it was observed that higher serum levels were associated with overall survival less than 60 months (p = 0.0382). In the evaluation of IL8, higher serum levels were associated with neutrophil-to-lymphocyte ratio (NLR) ≥ 4 and platelet-to-lymphocyte ratio (PLR) ≥ 200 (p = 0.0198 and p = 0.0072, respectively), altered values of serum CA125 (p = 0.0457), and stage IIIC (p = 0.0486). Therefore, increased levels of IL-6 and IL-8 are associated with factors of worse prognosis in ovarian cancer. Additional studies with a larger sample of patients are needed to confirm the role of cytokines as prognostic factors, in the definition of treatment, and in the development of future target therapies.

CD4+CD25highCD127low/-FoxP3+ Regulatory T Cell Subpopulations in the Bone Marrow and Peripheral Blood of Children with ALL: Brief Report

CD4⁺CD25^highCD127^low/-FoxP₃⁺ regulatory T cells (Tregs) are currently under extensive investigation in childhood acute lymphoblastic leukemia (ALL) and in other human cancers. Usually, Treg cells maintain the immune cell homeostasis. This small subset of T cells has been, in fact, considered to be involved in the pathogenesis of autoimmune diseases and progression of acute and chronic leukemias. However, whether Treg dysregulation in CLL and ALL plays a key role or it rather represents a simple epiphenomenon is still a matter of debate. Treg cells have been proposed as a prognostic indicator of the clinical course of the disease and might also be used for targeted immune therapy. Our study revealed statistically higher percentage of Treg cells in the bone marrow than in peripheral blood in the group of 42 children with acute lymphoblastic leukemia. By analyzing Treg subpopulations, it was shown that only memory Tregs in contact with leukemic antigens showed statistically significant differences. We noticed a low negative correlation between Treg cells in the bone marrow and the percentage of blasts (R = -0.36) as well as a moderate correlation between Treg cells in the bone marrow and Hb level (R = +0.41) in peripheral blood before therapy. The number of peripheral blood blasts on day 8th correlates negatively (R = -0.36) with Tregs. Furthermore, statistical analysis revealed low negative correlation between the number of Tregs in the bone marrow and the minimal residual disease measured on day 15th, the percentage of blasts in the bone marrow and leukocytosis after 15 days of chemotherapy. These results indicate the influence of Tregs on the final therapeutic effect.

Early and Partial Reduction in CD4+Foxp3+ Regulatory T Cells during Colitis-Associated Colon Cancer Induces CD4+ and CD8+ T Cell Activation Inhibiting Tumorigenesis

Colorectal cancer (CRC) is the second most commonly diagnosed cancer in women and the third in men in North America and Europe. CRC is associated with inflammatory responses in which intestinal pathology is caused by different cell populations including a T cell dysregulation that concludes in an imbalance between activated T (Tact) and regulatory T (Treg) cells. Treg cells are CD4⁺Foxp3⁺ cells that actively suppress pathological and physiological immune responses, contributing to the maintenance of immune homeostasis. A tumor-promoting function for Treg cells has been suggested in CRC, but the kinetics of Treg cells during CRC development are poorly known. Therefore, using a mouse model of colitis-associated colon cancer (CAC) induced by azoxymethane and dextran sodium sulfate, we observed the dynamic and differential kinetics of Treg cells in blood, spleen and mesenteric lymph nodes (MLNs) as CAC progresses, highlighting a significant reduction in Treg cells in blood and spleen during early CAC development, whereas increasing percentages of Treg cells were detected in late stages in MLNs. Interestingly, when Treg cells were decreased, Tact cells were increased and vice versa. Treg cells from late stages of CAC displayed an activated phenotype by expressing PD1, CD127 and Tim-3, suggesting an increased suppressive capacity. Suppression assays showed that T-CD4⁺ and T-CD8⁺ cells were suppressed more efficiently by MLN Treg cells from CAC animals. Finally, an antibody-mediated reduction in Treg cells during early CAC development resulted in a better prognostic value, because animals showed a reduction in tumor progression associated with an increased percentage of activated CD4⁺CD25⁺Foxp3^- and CD8⁺CD25⁺ T cells in MLNs, suggesting that Treg cells suppress T cell activation at early steps during CAC development.

Regulatory T Cells and Their Prognostic Relevance in Hematologic Malignancies

Regulatory T cells (Tregs) have a fundamental function in monitoring the immune homeostasis in healthy individuals. In cancer and, in particular, in hematological malignancies, Tregs exert a major immunosuppressive activity, thus playing a critical role in tumor cell growth, proliferation, and survival. Here, we summarize published data on the prognostic significance of Tregs in hematological malignancies and show that they are highly conflicting. The heterogeneity of the experimental approaches that were used explains-at least in part-the discordant results reported by different groups that have investigated the role of Tregs in cancer. In fact, different tissues have been studied (i.e., peripheral blood, bone marrow, and lymph node), applying different methods (i.e., flow cytometry versus immunohistochemistry, whole blood versus isolated peripheral blood mononuclear cells versus depletion of CD25⁺ cells, various panels of monoclonal antibodies, techniques of fixation and permeabilization, and gating strategies). This is of relevance in order to stress the need to apply standardized approaches in the study of Tregs in hematological malignancies and in cancer in general.

A First-in-Human Phase I Study of Subcutaneous Outpatient Recombinant Human IL15 (rhIL15) in Adults with Advanced Solid Tumors

Purpose: Preclinical data established IL15 as a homeostatic factor and powerful stimulator of NK and CD8⁺ T-cell function, the basis for clinical testing.Experimental Design: A first-in-human outpatient phase I dose escalation trial of subcutaneous (SC) rhIL15 was conducted in refractory solid tumor cancer patients. Therapy consisted of daily (Monday-Friday) subcutaneous injections of rhIL15 for two consecutive weeks (10 total doses/cycle). Clinical response was assessed by RECIST. Pharmacokinetics of rhIL15 and immune biomarkers were evaluated.Results: Nineteen patients were treated with rhIL15 at dose levels of 0.25, 0.5, 1, 2, and 3 mcg/kg/day. Fourteen patients completed ≥ 2 cycles of therapy that was well tolerated. One serious adverse event (SAE), grade 2 pancreatitis, required overnight hospitalization. Enrollment was halted after a patient receiving 3 mcg/kg/day developed a dose-limiting SAE of grade 3 cardiac chest pain associated with hypotension and increased troponin. No objective responses were observed; however, several patients had disease stabilization including a renal cell carcinoma patient who continued protocol treatment for 2 years. The treatment induced profound expansion of circulating NK cells, especially among the CD56^bright subset. A proportional but less dramatic increase was found among circulating CD8⁺ T cells with maximal 3-fold expansion for the 2 and 3 mcg/kg patients.Conclusions: SC rhIL15 treatment was well tolerated, producing substantial increases in circulating NK and CD8⁺ T cells. This protocol establishes a safe outpatient SC rhIL15 regimen of 2 mcg/kg/day dosing amenable to self-injection and with potential as a combination immunotherapeutic agent. Clin Cancer Res; 24(7); 1525-35. ©2017 AACR.

Using MRI cell tracking to monitor immune cell recruitment in response to a peptide-based cancer vaccine

PURPOSE

MRI cell tracking can be used to monitor immune cells involved in the immunotherapy response, providing insight into the mechanism of action, temporal progression of tumor growth, and individual potency of therapies. To evaluate whether MRI could be used to track immune cell populations in response to immunotherapy, CD8⁺ cytotoxic T cells, CD4⁺ CD25⁺ FoxP3⁺ regulatory T cells, and myeloid-derived suppressor cells were labeled with superparamagnetic iron oxide particles.

METHODS

Superparamagnetic iron oxide-labeled cells were injected into mice (one cell type/mouse) implanted with a human papillomavirus-based cervical cancer model. Half of these mice were also vaccinated with DepoVax^TM (ImmunoVaccine, Inc., Halifax, Nova Scotia, Canada), a lipid-based vaccine platform that was developed to enhance the potency of peptide-based vaccines.

RESULTS

MRI visualization of CD8⁺ cytotoxic T cells, regulatory T cells, and myeloid-derived suppressor cells was apparent 24 h post-injection, with hypointensities due to iron-labeled cells clearing approximately 72 h post-injection. Vaccination resulted in increased recruitment of CD8⁺ cytotoxic T cells, and decreased recruitment of myeloid-derived suppressor cells and regulatory T cells to the tumor. We also found that myeloid-derived suppressor cell and regulatory T cell recruitment were positively correlated with final tumor volume.

CONCLUSION

This type of analysis can be used to noninvasively study changes in immune cell recruitment in individual mice over time, potentially allowing improved application and combination of immunotherapies. Magn Reson Med 80:304-316, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

The relative change in regulatory T cells / T helper lymphocytes ratio as parameter for prediction of therapy efficacy in metastatic colorectal cancer patients

Purpose

The evaluation of regulatory T (Treg) (CD4⁺CD25^high CD127^neg) lymphocyte count with respect to the T helper (TH) (CD4) number has been shown to represent the main immune parameters capable of signifying the functional status of the anticancer immunity in cancer patients. This study is aimed to explore a correlation between therapy efficacy and changes in Treg/TH ratio and other biochemical and haematological parameters in patients with metastatic colorectal cancer (mCRC).

Experimental Design

Measurements of regulatory T cells were performed by flow cytometric analysis pre- and post-therapies in a prospective study.

Results

We investigated levels of Treg/TH ratio in the peripheral blood of 25 mCRC patients pre- and post-chemotherapy ± targeted therapy. There were significant differences in levels of Treg/TH ratio pre- and post-treatments among patients on study, patients with partial response (PR), stable disease (SD) and progressive disease (PD) (P= 0.012, P= 0.011, and P= 0.043, respectively). Moreover, the relative change in Treg/TH ratio showed statistically significant difference among patients with PD as compared to those with PR and SD. Our findings demonstrated a statistically significant strong correlation between the relative change in Treg/TH ratio and therapeutic response. (Spearman's rho= 0.788/p<0.001).

Conclusions

The monitoring of the relative change in Treg/TH ratio could constitute a promising clinical index for response prediction and a timely change in regimen. Further prospective evaluations of these parameters investigated, particularly their association with overall survival, are warranted.

Local High-Dose Radiotherapy Induces Systemic Immunomodulating Effects of Potential Therapeutic Relevance in Oligometastatic Breast Cancer

Local irradiation of cancer through radiotherapy can induce spontaneous regression of non-directly irradiated lesions, suggesting the involvement of systemic antitumor immune responses. In oligometastatic breast cancer (BC) patients, the use of stereotactic body radiotherapy (SBRT) favors the local control of treated lesions and may contribute to break local tolerance and release tumor-associated antigens (TAAs), improving host antitumor immunity. We performed a detailed immunomonitoring of BC patients undergoing SBRT to verify its ability to “switch on” the anti-tumor immunity both systemically, in peripheral blood, and locally, employing in vitro BC models. Twenty-one BC patients with ≤6 metastases were treated with 3 daily doses of 10 Gy with SBRT. Blood samples for immune profiling were collected before and after treatment. One month after treatment a third of patients displayed the boosting or even the de novo appearance of polyfunctional CD4⁺ and CD8⁺ T cell responses against known BC TAAs (survivin, mammaglobin-A, HER2), through intracellular staining in flow cytometry. Half of patients showed increased numbers of activated natural killer (NK) cells, measured with multispectral flow cytometry, immediately after the first dose of SBRT. Interestingly, high levels of activated NK cells at diagnosis correlated with a longer progression-free survival. BC in vitro models, treated with the same SBRT modality, showed enhanced expression of MHC class-I and class-II, major histocompatibility complex class I-related chain A/B, and Fas molecules, and increased release of pro-inflammatory cytokines, such as IL-1β and TNF-α. Consistently, we noticed enhanced production of perforin by CD4⁺ T cells when patients’ lymphocytes were cultured in the presence of irradiated BC cell line, compared to untreated targets. Besides immunogenic effects, SBRT also enhanced the percentages of circulating regulatory T cells, and increased indoleamine 2,3 dioxygenase and PD-L1 expression in BC in vitro models. These results suggest that SBRT may boost host antitumor immune responses also in an advanced disease setting such as oligometastatic BC, by inducing immunomodulating effects both locally and systemically. However, the concomitant induction of immunosuppressive pathways suggests that a combination with immunotherapy could further enhance the in situ vaccination ability of radiotherapy, possibly further improving the curative potential of SBRT in this subset of patients.

Newly Characterized Murine Undifferentiated Sarcoma Models Sensitive to Virotherapy with Oncolytic HSV-1 M002

Despite advances in conventional chemotherapy, surgical techniques, and radiation, outcomes for patients with relapsed, refractory, or metastatic soft tissue sarcomas are dismal. Survivors often suffer from lasting morbidity from current treatments. New targeted therapies with less toxicity, such as those that harness the immune system, and immunocompetent murine sarcoma models to test these therapies are greatly needed. We characterized two new serendipitous murine models of undifferentiated sarcoma (SARC-28 and SARC-45) and tested their sensitivity to virotherapy with oncolytic herpes simplex virus 1 (HSV-1). Both models expressed high levels of the primary HSV entry molecule nectin-1 (CD111) and were susceptible to killing by interleukin-12 (IL-12) producing HSV-1 M002 in vitro and in vivo. M002 resulted in a significant intratumoral increase in effector CD4⁺ and CD8⁺ T cells and activated monocytes, and a decrease in myeloid-derived suppressor cells (MDSCs) in immunocompetent mice. Compared to parent virus R3659 (no IL-12 production), M002 resulted in higher CD8:MDSC and CD8:T regulatory cell (Treg) ratios, suggesting that M002 creates a more favorable immune tumor microenvironment. These data provide support for clinical trials targeting sarcomas with oncolytic HSV-1. These models provide an exciting opportunity to explore combination therapies for soft tissue sarcomas that rely on an intact immune system to reach full therapeutic potential.

IL-33 blockade suppresses tumor growth of human lung cancer through direct and indirect pathways in a preclinical model

Non-small-cell lung cancer (NSCLC) is the most common type in lung cancer, a leading cause of cancer-related death worldwide. Our previous study unraveled a pro-cancer function of IL-33 in fueling outgrowth and metastasis of human NSCLC cells. Herein, we determined that interfere with IL-33 activity was an effective strategy for limiting NSCLC tumor growth using a preclinical model with human NSCLC xenografts. IL-33 blockade efficiently inhibited tumor growth of NSCLC xenografts in immune-deficient mice. Mechanistically, IL-33 blockade suppressed outgrowth capacity of human NSCLC cells. Meanwhile, IL-33 blockade abrogated polarization of M2 tumor-associated macrophages (TAMs) and reduced accumulation of regulatory T cells (Tregs) in tumor microenvironments, shaping functional immune surveillance. In NSCLC patients, IL-33 expressions were positively correlated with Ki-67 proliferation index and expressions of M2 TAM- and Teg-related genes. These findings identify IL-33 as a dual-functional factor in NSCLC pathogenesis and suggest IL-33 blockade as a promising therapeutic for NSCLC patients.

The metastasis status and tumor burden-associated CA125 level combined with the CD4/CD8 ratio predicts the prognosis of patients with advanced pancreatic cancer: A new scoring system

INTRODUCTION

Although CA125 and the tumor immune response have been reported to be associated with pancreatic cancer, their prognostic value for advanced pancreatic cancer patients undergoing chemotherapy remain uncertain. We thus studied the prognostic value of the combination of the CA125 level with the CD4/CD8 ratio.

METHODS

After excluding patients who were lost to follow-up or for whom complete clinical data were missing, 369 participants were ultimately examined. Univariate and multivariate analyses were performed using the Cox hazards model, and Kaplan-Meier methods and log-rank tests were used for the comparison of survival rates.

RESULTS

Univariate and multivariate analyses showed that a high CA125 level and a high CD4/CD8 ratio were independent prognostic factors (CA125 ≥ 35 U/ml, Hazard Ratio (HR) = 1.90, p < 0.001; CD4/CD8 ≥ 1.8, HR = 1.37, p = 0.004). Moreover, after combining the CA125 level and CD4/CD8 ratio to form a new scoring system, the HR was substantially elevated (CA125 ≥ 35 U/ml and CD4/CD8 ≥ 1.8, score 2, HR = 2.76, 95% confidence interval: 2.04 to 3.74, p < 0.001).

CONCLUSIONS

A new scoring system based on the combination of the CA125 level with the CD4/CD8 ratio could further predict the prognosis of patients with advanced pancreatic cancer.

Immunotherapy of WAP-TNP mice with early stage mammary gland tumors

The SV40 transgenic BALB/c mouse based WAP-T/WAP-T_NP model for triple-negative breast cancer allows the analysis of parameters influencing immunotherapeutic approaches. Except for WAP-T_NP tumors expressing the immune-dominant LCMV NP-epitope within SV40 T-antigen (T-Ag_NP) which is not expressed by T-Ag of WAP-T tumors, the tumors are extremely similar. Comparative anti-PD1/PD-L1 immunotherapy of WAP-T and WAP-T_NP mice supported the hypothesis that the immunogenicity of tumor antigen T-cell epitopes strongly influences the success of immune checkpoint blockade therapy, with highly immunogenic T-cell epitopes favoring rapid CTL exhaustion. Here we analyzed the immune response in NP8 mice during early times of tumor development. LCMV infection of lactating NP8 mice induced lifelong tumor protection by memory CTLs. Immunization with LCMV after involution and appearance of T-Ag_NP expressing parity-induced tumor progenitor cells could not cure the mice, as memory CTLs became exhausted. However, immunization significantly prolonged the time of tumor outgrowth. Elimination of exhausted CTLs and of immunosuppressive cells by sub-lethal γ-irradiation, followed by adoptive transfer of NP-epitope specific CTLs into NP8 tumor mice with early lesions, completely prevented tumor outgrowth, when lymphocytes obtained after injection of weakly immunogenic NP8 tumor-derived cells into BALB/c mice were transferred. Transfer of lymphocytes obtained after infection of BALB/c mice with highly immunogenic LCMV into such mice delayed tumor outgrowth for a significant period, but could not prevent it. We conclude that eliminating exhausted CTLs and immune-suppressive cells followed by transfer or generation of low-avidity tumor antigen-specific CTLs might be a promising approach for curative tumor immunotherapy.

What Else Can CD39 Tell Us?

As the rate-limiting enzyme in ATP/ADP–AMP–adenosine pathway, CD39 would be a novel checkpoint inhibitor target in preventing adenosine-triggered immune-suppressive effect. In addition, CD39^hi Tregs, but not CD25^hi Tregs, exhibit sustained Foxp3 levels and functional abilities, indicating it could represent a new specific marker of Tregs. Similarly, inhibition of CD39 enzymatic function at the surface of tumor cells alleviates their immunosuppressive activity. Far from conclusive, present research revealed that CD39 also dephosphorylated and thus inactivated self- and pathogen-associated phosphoantigens of Vγ9Vδ2 T cells, which may be the most promising subpopulation for cellular vaccine. CD39 is also tightly related to Th17 cells and can be regarded as a Th17 cells marker. In this review, we focus on present research of CD39 ectoenzyme and provide insights into its clinical application.