Molecular profiling to identify relevant immune resistance mechanisms in the tumor microenvironment

The roles of genetic mutation and cytokines/chemokines in immune response and their association with uveal melanoma patient outcome

The impact of tumor mutations and the interplay of cytokines and chemokines on the immune response and clinical outcomes in uveal melanoma (UM) warrants further exploration. In our study, we delved into the correlation between genetic alterations and survival rates in a cohort of 188 UM patients, utilizing data from cBioPortal. We assessed the composition of immune cell populations within 80 UM tumors by examining RNA sequence-based gene expression data from The Cancer Genome Atlas (TCGA). Furthermore, we scrutinized the relationship between genetic mutations and the expression of cytokines and chemokines, as well as their influence on various immune cell subsets. Our investigation revealed a significant association between the presence of mutated GNAQ or SF3B1 genes and improved progression-free survival (PFS), disease-specific survival (DSS), and overall survival (OS) when compared to patients with non-mutated counterparts. In contrast, the presence of immune response gene mutations was associated with a detrimental effect on PFS, DSS, and OS. We also observed that the expression levels of cytokines and chemokines were positively linked to the infiltration of immune killer cells and inversely related to the populations of B cells and dendritic cells. Elevated expression levels of PDCD1, TNF, IL6, CXCL9, and CXCL10 were found to be correlated with reduced OS. Intriguingly, an increase in CD8+ T cell populations was associated with a poorer OS, a finding that warrants further investigation. These findings underscore the potential utility of cytokines/chemokines expression levels, immune cell subsets, and mutation status as critical biomarkers for the selection of patients who are most likely to benefit from immunotherapeutic interventions. Our research provides valuable insights that could guide the development of more targeted and effective treatment strategies for UM patients.

Safety and efficacy of immune checkpoint inhibitors after allogeneic hematopoietic cell transplantation

The immune system plays a major role in preventing infections and cancers. Impairment in immunity may facilitate the development of neoplasia owing to defective immune surveillance, among other mechanisms. Immune evasion plays a significant role in relapse after allogeneic hematopoietic cell transplantation (alloHCT); one purported mechanism is through immune checkpoint signaling pathways. Checkpoint inhibitors (CPIs) are FDA approved for relapsed classical Hodgkin's Lymphoma (cHL), primary mediastinal large B cell Lymphoma (PMBCL) and other solid tumors. Retrospective studies evaluating the outcomes of alloHCT after prior exposure to CPIs showed favorable survival outcomes but high rates of graft-versus-host disease (GVHD); the risk appears to be lower when using post-transplant cyclophosphamide as GVHD prophylaxis. CPIs have increasingly been used to prevent or treat post-alloHCT relapse. Available data, albeit limited, supports the clinical activity of CPIs in post-alloHCT relapse; however, serious and even fatal cases of GVHD have been reported. The optimal timing, schedule, dosing, and patients likely to benefit from this strategy are yet to be identified. In this review, we highlight the immune system's role in cancer surveillance and relapse prevention and discuss the current clinical evidence of CPIs use in post-alloHCT relapse.

BCAT2 Shapes a Noninflamed Tumor Microenvironment and Induces Resistance to Anti-PD-1/PD-L1 Immunotherapy by Negatively Regulating Proinflammatory Chemokines and Anticancer Immunity

To improve response rate of monotherapy of immune checkpoint blockade (ICB), it is necessary to find an emerging target in combination therapy. Through analyzing tumor microenvironment (TME)-related indicators, it is validated that BCAT2 shapes a noninflamed TME in bladder cancer. The outcomes of multiomics indicate that BCAT2 has an inhibitory effect on cytotoxic lymphocyte recruitment by restraining activities of proinflammatory cytokine/chemokine-related pathways and T-cell-chemotaxis pathway. Immunoassays reveal that secretion of CD8+ T-cell-related chemokines keeps a robust negative correlation with BCAT2, generating a decreasing tendency of CD8+ T cells around BCAT2+ tumor cells from far to near. Cotreatment of BCAT2 deficiency and anti-PD-1 antibody has a synergistic effect in vivo, implying the potential of BCAT2 in combination therapy. Moreover, the value of BCAT2 in predicting efficacy of immunotherapy is validated in multiple immunotherapy cohorts. Together, as a key molecule in TME, BCAT2 is an emerging target in combination with ICB and a biomarker of guiding precision therapy.

Recent Advances of RNA m6A Modifications in Cancer Immunoediting and Immunotherapy

Cancer immunotherapy, which modulates immune responses against tumors using immune-checkpoint inhibitors or adoptive cell transfer, has emerged as a novel and promising therapy for tumors. However, only a minority of patients demonstrate durable responses, while the majority of patients are resistant to immunotherapy. The immune system can paradoxically constrain and promote tumor development and progression. This process is referred to as cancer immunoediting. The mechanisms of resistance to immunotherapy seem to be that cancer cells undergo immunoediting to evade recognition and elimination by the immune system. RNA modifications, specifically N6-methyladenosine (m6A) methylation, have emerged as a key regulator of various post-transcriptional gene regulatory processes, such as RNA export, splicing, stability, and degradation, which play unappreciated roles in various physiological and pathological processes, including immune system development and cancer pathogenesis. Therefore, a deeper understanding of the mechanisms by which RNA modifications impact the cancer immunoediting process can provide insight into the mechanisms of resistance to immunotherapies and the strategies that can be used to overcome such resistance. In this chapter, we briefly introduce the background of cancer immunoediting and immunotherapy. We also review and discuss the roles and mechanisms of RNA m6A modifications in fine-tuning the innate and adaptive immune responses, as well as in regulating tumor escape from immunosurveillance. Finally, we summarize the current strategies targeting m6A regulators for cancer immunotherapy.

Type I and II interferon signaling in colorectal cancer liver metastasis

Metastatic colorectal cancer is one of the leading causes of cancer-related deaths worldwide. Traditional chemotherapy extended the lifespan of cancer patients by only a few months, but targeted therapies and immunotherapy prolonged survival and led to long-term remissions in some cases. Type I and II interferons have direct pro-apoptotic and anti-proliferative effects on cancer cells and stimulate anti-cancer immunity. As a result, interferon production by cells in the tumor microenvironment is in the spotlight of immunotherapies as it affects the responses of anti-cancer immune cells. However, promoting effects of interferons on colorectal cancer metastasis have also been reported. Here we summarize our knowledge about pro- and anti-metastatic effects of type I and II interferons in colorectal cancer liver metastasis and discuss possible therapeutic implications.

Immune-checkpoint inhibitor use in patients with cancer and pre-existing autoimmune diseases

Immune-checkpoint inhibitors (ICIs) have dramatically changed the management of advanced cancers. Designed to enhance the antitumour immune response, they can also cause off-target immune-related adverse events (irAEs), which are sometimes severe. Although the efficacy of ICIs suggests that they could have wide-ranging benefits, clinical trials of the drugs have so far excluded patients with pre-existing autoimmune disease. However, evidence is accumulating with regard to the use of ICIs in this 'at-risk' population, with retrospective data suggesting that they have an acceptable safety profile, but that there is a risk of disease flare or other irAE occurrence. The management of immunosuppressive drugs at ICI initiation in patients with autoimmune disease (or later in instances of disease flare or irAE) remains a question of particular interest in clinical practice, in which there is always a search for the balance between protecting against autoimmunity and ensuring a good tumour response. Although temporary use of immunosuppressants seems safe, prolonged use or use at ICI initiation might hamper the antitumour immune response, prompting clinicians to use the minimal efficient immunosuppressive regimen. However, a new paradigm is emerging, in which inhibitors of TNF or IL-6 could have synergistic effects with ICIs on tumour response, while also preventing severe irAEs. If confirmed, this 'decoupling' effect on toxicity and efficacy could change therapeutic practice in this field. Knowledge of the current use of ICIs in patients with pre-existing autoimmune disease, particularly with regard to the use of immunosuppressive drugs and/or biologic DMARDs, can help to guide clinical practice.

Immune Tolerance vs. Immune Resistance: The Interaction Between Host and Pathogens in Infectious Diseases

The immune system is most likely developed to reduce the harmful impact of infections on the host homeostasis. This defense approach is based on the coordinated activity of innate and adaptive immune system components, which detect and target infections for containment, killing, or expulsion by the body's defense mechanisms. These immunological processes are responsible for decreasing the pathogen burden of an infected host to maintain homeostasis that is considered to be infection resistance. Immune-driven resistance to infection is connected with a second, and probably more important, defensive mechanism: it helps to minimize the amount of dysfunction imposed on host parenchymal tissues during infection without having a direct adverse effect on pathogens. Disease tolerance is a defensive approach that relies on tissue damage control systems to prevent infections from causing harm to the host. It also uncouples immune-driven resistance mechanisms from immunopathology and disease, allowing the body to fight infection more effectively. This review discussed the cellular and molecular processes that build disease tolerance to infection and the implications of innate immunity on those systems. In addition, we discuss how symbiotic relationships with microbes and their control by particular components of innate and adaptive immunity alter disease tolerance to infection.

High Intensity Aerobic exercise training and Immune cell Mobilization in patients with lung cancer (HI AIM)—a randomized controlled trial

Background

The increasing role of exercise training in cancer care is built on evidence that exercise can reduce side effects of treatment, improve physical functioning and quality of life. We and others have shown in mouse tumor models, that exercise leads to an adrenalin-mediated increased influx of T and NK cells into the tumor, altering the tumor microenvironment (TME) and leading to reduced tumor growth. These data suggest that exercise could improve immune responses against cancer cells by increase immune cell infiltration to the tumor and potentially having an impact on disease progression. Additionally, there are data to suggest that infiltration of T and NK cells into the TME is correlates with response to immune checkpoint inhibitors in patients. We have therefore initiated the clinical trial HI AIM, to investigate if high intensity exercise can mobilize and increase infiltration of immune cells in the TME in patients with lung cancer.

Methods

HI AIM (NCT04263467) is a randomized controlled trial (70 patients, 1:1) for patients with non-small cell lung cancer. Patients in the treatment arm, receive an exercise-intervention consisting of supervised and group-based exercise training, comprising primarily intermediate to high intensity interval training three times per week over 6 weeks. All patients will also receive standard oncological treatments; checkpoint inhibitors, checkpoint inhibitors combined with chemotherapy or oncological surveillance. Blood samples and biopsies (ultrasound guided), harvested before, during and after the 6-week training program, will form basis for immunological measurements of an array of immune cells and markers. Primary outcome is circulating NK cells. Secondary outcome is other circulating immune cells, infiltration of immune cells in tumor, inflammatory markers, aerobic capacity measured by VO₂ max test, physical activity levels and quality of life measured by questionnaires, and clinical outcomes.

Discussion

To our knowledge, HI AIM is the first project to combine supervised and monitored exercise in patients with lung cancer, with rigorous analyses of immune and cancer cell markers over the course of the trial. Data from the trial can potentially support exercise as a tool to mobilize cells of the immune system, which in turn could potentiate the effect of immunotherapy.

Trial registration

The study was prospectively registered at ClinicalTrials.gov on February 10^th 2020, ID: NCT04263467. https://clinicaltrials.gov/ct2/show/NCT04263467

Targeting Cbx3/HP1γ Induces LEF-1 and IL-21R to Promote Tumor-Infiltrating CD8 T-Cell Persistence

Immune checkpoint blockade (ICB) relieves CD8⁺ T-cell exhaustion in most mutated tumors, and TCF-1 is implicated in converting progenitor exhausted cells to functional effector cells. However, identifying mechanisms that can prevent functional senescence and potentiate CD8⁺ T-cell persistence for ICB non-responsive and resistant tumors remains elusive. We demonstrate that targeting Cbx3/HP1γ in CD8⁺ T cells augments transcription initiation and chromatin remodeling leading to increased transcriptional activity at Lef1 and Il21r. LEF-1 and IL-21R are necessary for Cbx3/HP1γ-deficient CD8⁺ effector T cells to persist and control ovarian cancer, melanoma, and neuroblastoma in preclinical models. The enhanced persistence of Cbx3/HP1γ-deficient CD8⁺ T cells facilitates remodeling of the tumor chemokine/receptor landscape ensuring their optimal invasion at the expense of CD4⁺ Tregs. Thus, CD8⁺ T cells heightened effector function consequent to Cbx3/HP1γ deficiency may be distinct from functional reactivation by ICB, implicating Cbx3/HP1γ as a viable cancer T-cell-based therapy target for ICB resistant, non-responsive solid tumors.

[Current landscape of biomarker development for immune checkpoint inhibitors targeting PD-1/PD-L1 pathway in oncology]

The immune checkpoints inhibitors targeting PD-1 or PD-L1 represent a new paradigm in the cancer treatment strategy. However, some populations of patients do not benefit from these agents. The identification of predictive biomarkers appears as an essential step for the treatment pathway, to guarantee the access to an evidence-based medicine accounting for the potential toxicity profile, the cost for the healthcare system and the clinical benefit eventually provided by these new drugs. In this review, we propose, based on scientific literature and industrial communications, an overview of the current landscape of predictive biomarkers related to PD-1 or PD-L1 inhibitors efficacy, validated or under development, their evidence level, and limits accounting for identified or potential confounding factors. Our paper shows that, despite the important amount of work performed in this field, there is not yet a validated and efficient solution for the prediction of the activity and/or the toxicity of anti-PD-1 and anti-PD-L1 antibodies.

NK and NKT cells have distinct properties and functions in cancer

Natural killer (NK) and natural killer T (NKT) cells are two important cell subsets of the innate immune system. NK and NKT cells share many phenotypes and functions for anti-tumor immunity; however, the dynamic changes in phenotypes and functional interactions within the tumor microenvironment during tumor development and progression are unknown. Here we report that NK and NKT cells have distinct properties, metabolic profiles, and functions during tumor development. Using the mouse E0771 breast cancer and B16 melanoma models, we found that both NK and NKT cells are dynamically involved in the immune responses to cancer but have distinct distributions and phenotypic profiles in tumor sites and other peripheral organs during the course of tumor development and progression. In the early stages of tumor development, both NK and NKT cells exhibit effector properties. In the later cancer stages, NK and NKT cells have impaired cytotoxic capacities and dysfunctional states. NK cells become senescent cells, while NKT cells, other than invariant NKT (iNKT) cells, are exhausted in the advanced cancers. In contrast, iNKT cells develop increases in activation and effector function within the breast tumor microenvironment. In addition, senescent NK cells have heightened glucose and lipid metabolism, but exhausted NKT cells display unbalanced metabolism in tumor microenvironments of both breast cancer and melanoma tumor models. These studies provide a better understanding of the dynamic and distinct functional roles of NK and NKT cells in anti-tumor immunity, which may facilitate the development of novel immunotherapies targeting NK and NKT cells for cancer treatment.

Abscopal Effects of Local Radiotherapy Are Dependent on Tumor Immunogenicity

Although abscopal tumor regression remains a rare phenomenon, interest in exploiting how radiation stimulates the immune system to induce systemic abscopal response is increasing. Here, we tested the hypothesis that tumor immunogenicity determined the ability of radiotherapy to induce abscopal effects. We established highly (MC-38 and E.G7-OVA) or poorly (LL/2 and B16-F10) immunogenic tumor models in this study and treated them with sham radiation, a single dose of 15 Gy, or three fractions of 5 Gy on three consecutive days. Alterations in the tumor microenvironment after radiation were examined by flow cytometry and RNA sequencing. Our results demonstrated the positive correlation between tumor immunogenicity and the abscopal effect of radiotherapy. The single dose of 15 Gy radiation was an effective regimen for inducing abscopal effects in highly immunogenic tumors. Local radiation reshaped the tumor microenvironment of irradiated and non-irradiated distant tumors by increasing CD8 T-cell infiltration and reducing suppressive immune cell accumulation. However, radiation alone was insufficient to elicit abscopal effects in poorly immunogenic tumors. No significant alterations were detected in the non-irradiated distant tumor microenvironment after radiation of poorly immunogenic tumors. In addition, tumor immunogenic subtypes were associated with the radiological response and clinical outcome of patients receiving radiotherapy. These findings indicated that tumor immunogenicity was the dominant characteristic that could predict the abscopal effect of radiotherapy. Our study provides an in-depth understanding of the immunological mechanisms involved in abscopal effects and highlights the impact of tumor heterogeneity on the therapeutic efficacy of radiotherapy and their combination with immunotherapy in clinical trials.

Evaluating the efficacy and safety of immune checkpoint inhibitors by detecting the exposure-response: An inductive review

Immune checkpoint inhibitors (ICIs) have been demonstrated an effective treatment in multiple tumor type, which restore the immune response to against cancer cell. Currently, approved ICIs include anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4); anti-programmed cell death 1 (PD-1) and anti-programmed cell death ligand 1 (PD-L1) monoclonal antibodies (mAbs). In most these drugs, unique pharmacokinetic (PK) and pharmacodynamics (PD) have shown significant influence on clinical outcomes, which occurred by target-mediated drug concentration and time-varying drug clearance. An exposure-response (E-R) relationship has been used to describe the safety and efficacy of ICIs, and shown a plateaued E-R and time dependent changes in exposure. Using an enzyme linked immunosorbent assay (ELISA) or LC-MS/MS method to measure the peak concentration, trough concentration or area under the curve (AUC) of ICIs to assess the drug exposure. There are lots of covariates that have an influence on exposure, such as sex, clearance, body weight and tumor burden. In this review, we pooled data from studies of concentration or other pharmacokinetics parameter of mAbs to assess E-R in efficacy and safety.

Oncolytic Reovirus-Mediated Recruitment of Early Innate Immune Responses Reverses Immunotherapy Resistance in Prostate Tumors

Prostate cancers are considered "cold" tumors characterized by minimal T cell infiltrates, absence of a type I interferon (IFN) signature, and the presence of immunosuppressive cells. This non-inflamed phenotype is likely responsible for the lack of sensitivity of prostate cancer patients to immune checkpoint blockade (ICB) therapy. Oncolytic virus therapy can potentially overcome this resistance to immunotherapy in prostate cancers by transforming cold tumors into "hot," immune cell-infiltrated tumors. We investigated whether the combination of intratumoral oncolytic reovirus, followed by targeted blockade of Programmed cell death protein 1 (PD-1) checkpoint inhibition and/or the immunomodulatory CD73/Adenosine system can enhance anti-tumor immunity. Treatment of subcutaneous TRAMP-C2 prostate tumors with combined intratumoral reovirus and anti-PD-1 or anti-CD73 antibody significantly enhanced survival of mice compared with reovirus or either antibody therapy alone. Only combination therapy led to rejection of pre-established tumors and protection from tumor re-challenge. This therapeutic effect was dependent on CD4+ T cells and natural killer (NK) cells. NanoString immune profiling of tumors confirmed that reovirus increased tumor immune cell infiltration and revealed an upregulation of the immune-regulatory receptor, B- and T-lymphocyte attenuator (BTLA). This expression of BTLA on innate antigen-presenting cells (APCs) and its ligand, Herpesvirus entry mediator (HVEM), on T cells from reovirus-infected tumors was in keeping with a role for the HVEM-BTLA pathway in promoting the potent anti-tumor memory response observed.

Cross-platform comparison of immune-related gene expression to assess intratumor immune responses following cancer immunotherapy

Neoadjuvant immunotherapy can induce immune responses within the tumor microenvironment. Gene expression can be used to assess responses with limited amounts of conventionally-fixed patient-derived samples. We aim to assess the cross-platform concordance of immune-related gene expression data. We performed comparisons across three panels in two platforms: Nanostring nCounter® PanCancer Immune Profiling Panel (nS), HTG EdgeSeq Oncology Biomarker Panel (HTG OBP) and Precision Immuno-Oncology Panel (HTG PIP). All tissue samples of 14 neoadjuvant GM-CSF treated, 14 neoadjuvant Provenge treated, and 12 untreated prostate cancer patients were radical prostatectomy (RP) tissues, while 6 prostatitis patients and 6 non-prostatitis subjects were biopsies. For all 52 patients, more than 90% of the common genes were significantly correlated (p < 0.05) and more than 76% of the common genes were highly correlated (r > 0.5) between any two panels. Co-inertia analysis also demonstrated high overall dataset structure similarity (correlation>0.84). Although both dimensionality reduction visualization analysis and unsupervised hierarchical cluster analysis for highly correlated common genes (r > 0.9) suggested a high-level of consistency across the panels, there were subsets of genes that were differentially expressed across the panels. In addition, while the effect size of the differential testing for neoadjuvant treated vs. untreated localized prostate cancer patients across the panels were significantly correlated, some genes were only differentially expressed in the HTG panels. Finally, the HTG PIP panel had the best classification performance among the 3 panels. These differences detected may be a result of the different panels or platforms due to their technical setting and focus. Thus, researchers should be aware of those potential differences when deciding which platform and panel to use.

Macrophage Plasticity and Function in the Lung Tumour Microenvironment Revealed in 3D Heterotypic Spheroid and Explant Models

In non-small cell lung cancer (NSCLC), stroma-resident and tumour-infiltrating macrophages may facilitate an immunosuppressive tumour microenvironment (TME) and hamper immunotherapeutic responses. Analysis of tumour-associated macrophage (TAM) plasticity in NSCLC is largely lacking. We established a novel, multi-marker, dual analysis approach for assessing monocyte-derived macrophage (Mφ) polarisation and M1/M2 phenotypic plasticity. We developed a flow cytometry-based, two-marker analysis (CD64 and CD206) of CD14⁺ cells. The phenotype and immune function of in vitro-induced TAMs was studied in a heterotypic spheroid and tumour-derived explant model of NSCLC. Heterotypic spheroids and NSCLC explants skewed Mφs from an M1- (CD206^loCD64^hi) to M2-like (CD206^hiCD64^lo) phenotype. Lipopolysaccharide (LPS) and IFNγ treatment reversed M2-like Mφ polarisation, indicating the plasticity of Mφs. Importantly, antigen-specific CD8⁺ T cell responses were reduced in the presence of tumour explant-conditioned Mφs, but not spheroid-conditioned Mφs, suggesting explants are likely a more relevant model of the immune TME than cell line-derived spheroids. Our data indicates the importance of multi-marker, functional analyses within Mφ subsets and the advantages of the ex vivo NSCLC explant model in immunomodulation studies. We highlight the plasticity of the M1/M2 phenotype using the explant model and provide a tool for studying therapeutic interventions designed to reprogram M2-like Mφ-induced immunosuppression.

Combined vaccination and immunostimulatory antibodies provides durable cure of murine melanoma and induces transcriptional changes associated with positive outcome in human melanoma patients

We have developed a recombinant adenovirus vaccine encoding dopachrome tautomerase (rHuAd5-hDCT) that produces robust DCT-specific immunity, but only provides modest suppression of murine melanoma. In the current study, an agonist antibody against 4-1BB was shown to enhance rHuAd5-hDCT efficacy and evoke tumor regression, but most tumors ultimately relapsed. The vaccine triggered upregulation of the immune inhibitory PD-1 signaling pathway and PD-1 blockade dramatically enhanced the rHuAd5-hDCT + anti-4-1BB strategy, resulting in complete regression of growing tumors in > 70% of recipients. The impact of the combined anti-4-1BB/anti-PD-1 treatment did not manifest as a dramatic enhancement in either the magnitude or functionality of DCT-specific tumor infiltrating lymphocytes relative to either treatment alone. Rather, a synergistic enhancement in intratumoral cytokine expression was observed, suggesting that the benefit of the combined therapy was a local event within the tumor. Global transcriptional analysis revealed immunological changes within the tumor following the curative vaccination, which extended beyond the T cell compartment. We identified an immune signature of 85 genes associated with clearance of murine melanoma that correlated with improved survival outcome in two independent cohorts of human melanoma patients. Our data reinforce the concept that successful vaccination must overcome local hurdles in the tumor microenvironment that are not manifest within the periphery. Further, tumor rejection following vaccination involves more than simply T cells. Finally, the association of our immune signature with positive survival outcome in human melanoma patients suggests that similar vaccination strategies may be promising for melanoma treatment.

Role of Regular Physical Exercise in Tumor Vasculature: Favorable Modulator of Tumor Milieu

The tumor vessel network has been investigated as a precursor of an inhospitable tumor microenvironment, including its repercussions in tumor perfusion, oxygenation, interstitial fluid pressure, pH, and immune response. Dysfunctional tumor vasculature leads to the extravasation of blood to the interstitial space, hindering proper perfusion and causing interstitial hypertension. Consequently, the inadequate delivery of oxygen and clearance of by-products of metabolism promote the development of intratumoral hypoxia and acidification, hampering the action of immune cells and resulting in more aggressive tumors. Thus, pharmacological strategies targeting tumor vasculature were developed, but the overall outcome was not satisfactory due to its transient nature and the higher risk of hypoxia and metastasis. Therefore, physical exercise emerged as a potential favorable modulator of tumor vasculature, improving intratumoral vascularization and perfusion. Indeed, it seems that regular exercise practice is associated with lasting tumor vascular maturity, reduced vascular resistance, and increased vascular conductance. Higher vascular conductance reduces intratumoral hypoxia and increases the accessibility of circulating immune cells to the tumor milieu, inhibiting tumor development and improving cancer treatment. The present paper describes the implications of abnormal vasculature on the tumor microenvironment and the underlying mechanisms promoted by regular physical exercise for the re-establishment of more physiological tumor vasculature.

Tumor Microenvironment: A Metabolic Player that Shapes the Immune Response

Immune cells survey and patrol throughout the body and sometimes take residence in niche environments with distinct cellular subtypes and nutrients that may fluctuate from those in which they matured. Rooted in immune cell physiology are metabolic pathways and metabolites that not only deliver substrates and energy for growth and survival, but also instruct effector functions and cell differentiation. Unlike cancer cells, immune cells are not subject to a "Darwinian evolutionary pressure" that would allow them to adapt to developing tumors but are often irrevocably affected to local nutrient deprivation. Thus, immune cells must metabolically adapt to these changing conditions in order to perform their necessary functions. On the other hand, there is now a growing appreciation that metabolic changes occurring in cancer cells can impact on immune cell functionality and contribute to tumor immune evasion, and as such, there is a considerable and growing interest in developing techniques that target metabolism for immunotherapy. In this review, we discuss the metabolic plasticity displayed by innate and adaptive immune cells and highlight how tumor-derived lactate and tumor acidity restrict immunity. To our knowledge, this review outlines the most recent insights on how tumor microenvironment metabolically instructs immune responsiveness.

Safety and Efficacy of Immune Checkpoint Inhibitors in Patients With Cancer and Preexisting Autoimmune Disease: A Nationwide, Multicenter Cohort Study

OBJECTIVE

Immune checkpoint inhibitors (ICIs) for cancer therapy frequently induce immune-related adverse effects (IRAEs). Therefore, most patients with preexisting autoimmune diseases have been excluded from clinical trials of ICIs. This study was undertaken to evaluate the safety and efficacy of ICIs in patients with preexisting autoimmune disease and cancer.

METHODS

A retrospective cohort study was conducted from January 2017 to January 2018 via 3 French national networks of experts in oncology and autoimmunity. Adults with preexisting autoimmune disease who were receiving ICIs were assessed for the occurrence of flare of preexisting autoimmune disease, other IRAEs, and cancer response.

RESULTS

The study included 112 patients who were followed up for a median of 8 months. The most frequent preexisting autoimmune diseases were psoriasis (n = 31), rheumatoid arthritis (n = 20), and inflammatory bowel disease (n = 14). Twenty-four patients (22%) were receiving immunosuppressive therapy at ICI initiation. Autoimmune disease flare and/or other IRAE(s) occurred in 79 patients (71%), including flare of preexisting autoimmune disease in 53 patients (47%) and/or other IRAE(s) in 47 patients (42%), with a need for immunosuppressive therapy in 48 patients (43%) and permanent discontinuation of ICI in 24 patients (21%). The median progression-free survival was shorter in patients receiving immunosuppressive therapy at ICI initiation (3.8 months versus 12 months; P = 0.006), confirmed by multivariable analysis. The median progression-free survival was shorter in patients who experienced a flare of preexisting autoimmune disease or other IRAE, with a trend toward better survival in the subgroup without immunosuppressant use or ICI discontinuation.

CONCLUSION

Our findings indicate that flares or IRAEs occur frequently but are mostly manageable without ICI discontinuation in patients with a preexisting autoimmune disease. Immunosuppressive therapy at baseline is associated with poorer outcomes.

An Oncolytic Adenovirus Targeting Transforming Growth Factor β Inhibits Protumorigenic Signals and Produces Immune Activation: A Novel Approach to Enhance Anti-PD-1 and Anti-CTLA-4 Therapy

In an effort to develop a new therapy for cancer and to improve antiprogrammed death inhibitor-1 (anti-PD-1) and anticytotoxic T lymphocyte-associated protein (anti-CTLA-4) responses, we have created a telomerase reverse transcriptase promoter-regulated oncolytic adenovirus rAd.sT containing a soluble transforming growth factor receptor II fused with human IgG Fc fragment (sTGFβRIIFc) gene. Infection of breast and renal tumor cells with rAd.sT produced sTGFβRIIFc protein with dose-dependent cytotoxicity. In immunocompetent mouse 4T1 breast tumor model, intratumoral delivery of rAd.sT inhibited both tumor growth and lung metastases. rAd.sT downregulated the expression of several transforming growth factor β (TGFβ) target genes involved in tumor growth and metastases, inhibited Th2 cytokine expression, and induced Th1 cytokines and chemokines, and granzyme B and perforin expression. rAd.sT treatment also increased the percentage of CD8⁺ T lymphocytes, promoted the generation of CD4⁺ T memory cells, reduced regulatory T lymphocytes (Tregs), and reduced bone marrow-derived suppressor cells. Importantly, rAd.sT treatment increased the percentage of CD4⁺ T lymphocytes, and promoted differentiation and maturation of antigen-presenting dendritic cells in the spleen. In the immunocompetent mouse Renca renal tumor model, similar therapeutic effects and immune activation results were observed. In the 4T1 mammary tumor model, rAd.sT improved the inhibition of tumor growth and lung and liver metastases by anti-PD-1 and anti-CTLA-4 antibodies. Analysis of the human breast and kidney tumors showed that a significant number of tumor tissues expressed high levels of TGFβ and TGFβ-inducible genes. Therefore, rAd.sT could be a potential enhancer of anti-PD-1 and anti-CTLA-4 therapy for treating breast and kidney cancers.

Cell Adhesion Molecules and Their Roles and Regulation in the Immune and Tumor Microenvironment

The immune system and cancer have a complex relationship with the immune system playing a dual role in tumor development. The effector cells of the immune system can recognize and kill malignant cells while immune system-mediated inflammation can also promote tumor growth and regulatory cells suppress the anti-tumor responses. In the center of all anti-tumor responses is the ability of the immune cells to migrate to the tumor site and to interact with each other and with the malignant cells. Cell adhesion molecules including receptors of the immunoglobulin superfamily and integrins are of crucial importance in mediating these processes. Particularly integrins play a vital role in regulating all aspects of immune cell function including immune cell trafficking into tissues, effector cell activation and proliferation and the formation of the immunological synapse between immune cells or between immune cell and the target cell both during homeostasis and during inflammation and cancer. In this review we discuss the molecular mechanisms regulating integrin function and the role of integrins and other cell adhesion molecules in immune responses and in the tumor microenvironment. We also describe how malignant cells can utilize cell adhesion molecules to promote tumor growth and metastases and how these molecules could be targeted in cancer immunotherapy.

A Task Force Against Local Inflammation and Cancer: Lymphocyte Trafficking to and Within the Skin

The skin represents a specialized site for immune surveillance consisting of resident, inflammatory and memory populations of lymphocytes. The entry and retention of T cells, B cells, and ILCs is tightly regulated to facilitate detection of pathogens, inflammation and tumors cells. Loss of individual or multiple populations in the skin may break tolerance or increase susceptibility to tumor growth and spread. Studies have significantly advanced our understanding of the role of skin T cells and ILCs at steady state and in inflammatory settings such as viral challenge, atopy, and autoimmune inflammation. The knowledge raised by these studies can benefit to our understanding of immune cell trafficking in primary melanoma, shedding light on the mechanisms of tumor immune surveillance and to improve immunotherapy. This review will focus on the T cells, B cells, and ILCs of the skin at steady state, in inflammatory context and in melanoma. In particular, we will detail the core chemokine and adhesion molecules that regulate cell trafficking to and within the skin, which may provide therapeutic avenues to promote tumor homing for a team of lymphocytes.

Regulation of T cell immunity by cellular metabolism

T cells are an important adaptive immune response arm that mediates cell-mediated immunity. T cell metabolism plays a central role in T cell activation, proliferation, differentiation, and effector function. Specific metabolic programs are tightly controlled to mediate T cell immune responses, and alterations in T cell metabolism may result in many immunological disorders. In this review, we will summarize the main T cell metabolic pathways and the important factors participating in T cell metabolic programming during T cell homeostasis, differentiation, and function.

Pan-cancer adaptive immune resistance as defined by the Tumor Inflammation Signature (TIS): results from The Cancer Genome Atlas (TCGA)

The Tumor Inflammation Signature (TIS) is an investigational use only (IUO) 18-gene signature that measures a pre-existing but suppressed adaptive immune response within tumors. The TIS has been shown to enrich for patients who respond to the anti-PD1 agent pembrolizumab. To explore this immune phenotype within and across tumor types, we applied the TIS algorithm to over 9000 tumor gene expression profiles downloaded from The Cancer Genome Atlas (TCGA). As expected based on prior evidence, tumors with known clinical sensitivity to anti-programmed cell death protein 1 (PD-1) blockade had higher average TIS scores. Furthermore, TIS scores were more variable within than between tumor types, and within each tumor type a subset of patients with elevated scores was identifiable although with different prevalence associated with each tumor type, the latter consistent with the observed clinical responsiveness to anti PD-1 blockade. Notably, TIS scores only minimally correlated with mutation load in most tumors and ranking tumors by median TIS score showed differing association to clinical sensitivity to PD-1/PD-1 ligand 1 (PD-L1) blockade than ranking of the same tumors by mutation load. The expression patterns of the TIS algorithm genes were conserved across tumor types yet appeared to be minimally prognostic in most cancers, consistent with the TIS score serving as a pan-cancer measurement of the inflamed tumor phenotype. Characterization of the prevalence and variability of TIS will lead to increased understanding of the immune status of untreated tumors and may lead to improved indication selection for testing immunotherapy agents.

Correlation of Neutrophil to Lymphocyte Ratio and Absolute Neutrophil Count With Outcomes With PD-1 Axis Inhibitors in Patients With Advanced Non-Small-Cell Lung Cancer

INTRODUCTION

Programmed death-1 (PD-1) axis inhibitors have become standard therapy in advanced non-small-cell lung cancer (NSCLC). Response might be delayed and pseudo-progression occasionally occurs in patients who eventually benefit from treatment. Additional markers beyond programmed death ligand 1 (PD-L1) expression are needed to assist in patient selection, response evaluation, and treatment decisions.

MATERIALS AND METHODS

The relationship between prospectively collected clinical outcomes (response, disease control rate [DCR], treatment duration, overall survival) and hematologic parameters (neutrophil to lymphocyte ratio [NLR], absolute neutrophil count [ANC], and platelet to lymphocyte ratio [PLR]) was explored retrospectively in advanced NSCLC patients treated with PD-1 axis inhibitors at a major cancer center from May 2013 to August 2016. Hematologic parameters at baseline and during treatment (week 2 or 3 and week 8) were included.

RESULTS

Of 88 patients treated with PD-1 axis inhibitors, 22 (25%) experienced partial response. Baseline NLR ≤4 was associated with superior DCR (74% vs. 50%; P = .025), treatment duration (P = .037), time to progression (P = .053), and overall survival (P = .019), with no differential association according to PD-L1 tumor expression. Lower NLR and ANC during treatment were also associated with response to treatment (P = .025 and P = .017, respectively), and treatment duration (P = .036 and P = .008). No association was found between baseline PLR and DCR, response, treatment duration, nor overall survival.

CONCLUSION

Baseline NLR ≤4 and lower NLR and ANC during treatment might correlate with disease control and treatment response and should be explored further as potential predictors of treatment benefit in larger studies.

Soluble programmed death-ligand 1 (sPDL1) and neutrophil-to-lymphocyte ratio (NLR) predicts survival in advanced biliary tract cancer patients treated with palliative chemotherapy

Programmed death-ligand 1 (PD-L1) expression in tumor tissue is under investigation as a candidate biomarker in immuno-oncology dug development. The soluble form of PD-L1 (sPDL1) is suggested to have immunosuppressive activity. In this study, we measured the serum level of sPDL1 and evaluated its prognostic implication in biliary tract cancer (BTC). Blood was collected from 158 advanced BTC patients (68 intrahepatic cholangiocarcinoma, 56 gallbladder cancer, 22 extrahepatic cholangiocarcinoma and 12 ampulla of vater cancer) before initiation of palliative chemotherapy. Serum sPDL1 was measured using an enzyme-linked immunosorbent assay. Clinical data included neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic immune-inflammation index (SII, neutrophil × platelet/lymphocyte). The patients were assigned to two cohorts (training and validation cohort) using a simple random sampling method to validate the cut-off value of each marker. Validation was performed using a twofold cross-validation method. Overall survival (OS) of all patients was 9.07 months (95% CI: 8.20-11.33). Median sPDL1 was 1.20 ng/mL (range 0.03-7.28, mean 1.50, SD 1.22). Median NLR, PLR and SII were 2.60, 142.85 and 584.93, respectively. Patients with high sPDL1 (≥0.94 ng/mL) showed worse OS than patients with low sPDL1 (7.93 vs. 14.10 months, HR 1.891 (1.35-2.65), p<0.001). In multivariate analysis, high sPDL1 and NLR were independent poor prognostic factors. In conclusion, serum sPDL1 can be measured and has significant role on the prognosis of advanced BTC patients treated with palliative chemotherapy.

Regulatory T cells trigger effector T cell DNA damage and senescence caused by metabolic competition

Defining the suppressive mechanisms used by regulatory T (Treg) cells is critical for the development of effective strategies for treating tumors and chronic infections. The molecular processes that occur in responder T cells that are suppressed by Treg cells are unclear. Here we show that human Treg cells initiate DNA damage in effector T cells caused by metabolic competition during cross-talk, resulting in senescence and functional changes that are molecularly distinct from anergy and exhaustion. ERK1/2 and p38 signaling cooperate with STAT1 and STAT3 to control Treg-induced effector T-cell senescence. Human Treg-induced T-cell senescence can be prevented via inhibition of the DNA damage response and/or STAT signaling in T-cell adoptive transfer mouse models. These studies identify molecular mechanisms of human Treg cell suppression and indicate that targeting Treg-induced T-cell senescence is a checkpoint for immunotherapy against cancer and other diseases associated with Treg cells.

Regulatory T (Treg) cells can induce senescence of tumour-associated effector T cells, but it is not clear how. Here the authors show that Treg cells outcompete effector T cells for glucose uptake, resulting in activation of the DNA damage response in effector T cells.

Exon 3 mutations of CTNNB1 drive tumorigenesis: a review

The canonical Wnt/β-catenin signaling pathway, an important modulator of progenitor cell proliferation and differentiation, is highly regulated for the maintenance of critical biological homeostasis. Decades of studies in cancer genetics and genomics have demonstrated that multiple genes encoding key proteins in this signaling pathway serve as targets for recurrent mutational alterations. Among these proteins, β-catenin and adenomatosis polyposis coli (APC) are two key nodes. β-catenin contributes in transporting extracellular signals for nuclear programming. Mutations of the CTNNB1 gene that encodes β-catenin occur in a wide spectrum of cancers. These mutations alter the spatial characteristics of the β-catenin protein, leading to drastic reprogramming of the nuclear transcriptional network. Among the outcomes of this reprogramming are increased cell proliferation, enhanced immunosuppression, and disruption of metabolic regulation. Herein we review the current understanding of CTNNB1 mutations, their roles in tumorigenesis and discuss their possible therapeutic implications for cancer.

HLA-mediated tumor escape mechanisms that may impair immunotherapy clinical outcomes via T-cell activation

Although the immune system provides protection from cancer by means of immunosurveillance, which serves a major function in eliminating cancer cells, it may also lead to cancer immunoediting, molding tumor immunogenicity. Cancer cells exploit several molecular mechanisms to thwart immune-mediated death by disabling cellular components of the immune system associated with tumor recognition and rejection. Human leukocyte antigen (HLA) molecules are mandatory for the immune recognition and subsequent killing of neoplastic cells by the immune system, as tumor antigens must be presented in an HLA-restricted manner to be recognized by T-cell receptors. Impaired HLA-I expression prevents the activation of cytotoxic immune mechanisms, whereas impaired HLA-II expression affects the antigen-presenting capability of antigen presenting cells. Aberrant HLA-G expression by cancer cells favors immune escape by inhibiting the activities of virtually all immune cells. The development of cancer therapies based on T-cell activation must consider these HLA-associated immune evasion mechanisms, as alterations in their expression occur early and frequently in the majority of types of cancer, and have an adverse impact on the clinical response to immunotherapy. Herein, the concept of altered HLA expression as a mechanism exploited by tumors to escape immune control and induce an immunosuppressive environment is reviewed. A number of novel clinical immunotherapeutic approaches used for cancer treatment are also reviewed, and strategies for overcoming the limitations of these immunotherapeutic interventions are proposed.

Development of mesenchymal subtype gene signature for clinical application in gastric cancer

Previously, in the Asian Cancer Research Group (ACRG) project, we defined four distinct molecular subtypes in gastric cancer (GC). Mesenchymal (microsatellite stable with epithelial-to-mesenchymal transition phenotype, MSS/EMT) tumors showed the worst prognosis among all the subtypes. To develop a gene signature for predicting mesenchymal subtype GC, we conducted gene expression profiling using a NanoString assay in 70 ACRG specimens. The gene signature was validated in an independent set obtained from the prospective Adjuvant chemoRadioTherapy In Stomach Tumor (ARTIST) trial. The association between the mesenchymal subtype and survival was investigated. After cross-platform concordance test performed in 70 ACRG specimens, a 71-gene MSS/EMT signature was obtained. In the validation set, the gene signature predicted that 20 of 73 (27%) patients had mesenchymal tumors. Patients with mesenchymal subtype had diffuse GC, poorly-differentiated or signet ring cell carcinoma, and were microsatellite stable. The estimated hazard ratio for survival in patients with mesenchymal GC compared to those with non-mesenchymal tumors was 2.262 (95% confidence interval, 1.410 to 3.636; P=0.001). The survival difference remained significant when the subtypes were analyzed according to clinical prognostic parameters. This study suggested that the NanoString-based 71-gene signature for mesenchymal subtype is a strong predictor of the outcome in patients with GC.

Systemic inflammation is associated with the density of immune cells in the tumor microenvironment of gastric cancer

BACKGROUND

The neutrophil-lymphocyte ratio (NLR) and the prognostic nutritional index (PNI) are markers of systemic inflammation known to be useful prognostic indicators of malignancy. However, little evidence has defined the influence of inflammation on the tumor microenvironment.

METHODS

Two hundred eighty-eight patients who underwent curative surgery for gastric cancer were included. Preoperative peripheral blood samples were used to analyze the NLR and PNI. The optimal cutoff levels for the NLR and PNI were defined by receiver operating characteristic curve analysis for survival (NLR = 2.7, PNI = 47.7). The densities of specific immune cells (CD3⁺, CD4⁺, CD8⁺) within the tumor microenvironment were measured in tumor microarrays by immunohistochemical analysis.

RESULTS

Two hundred thirty-five patients (81.6 %) had a low NLR and 53 patients (18.4 %) had a high NLR. One hundred seventeen patients (40.6 %) had a low PNI and 171 patients (59.4 %) had a high PNI. CD3⁺ and CD8⁺ immune cell density were not associated with the NLR and PNI. However, in the high-NLR group compared with the low-NLR group, CD4⁺ immune cell density was significantly decreased (P < 0.001). Similarly, the density of CD4⁺ immune cells was also significantly decreased in the low-PNI group compared with the high-PNI group (P = 0.007). A high NLR and a low PNI were correlated with worse overall survival in multivariate analysis (P = 0.028 and P = 0.002 respectively).

CONCLUSIONS

The NLR and PNI are associated with the density of CD4⁺ immune cells in the tumor microenvironment, which leads to prognostic values of systemic inflammation in gastric cancer.

Constitutive and acquired mechanisms of resistance to immune checkpoint blockade in human cancer

Cancer immunotherapy with monoclonal antibodies directed against regulatory pathways in T lymphocytes has been revolutionizing medical oncology, and the clinical success of monoclonal antibodies targeting either cytotoxic T lymphocyte antigen-4 (CTLA-4) or program death-1 (PD-1) in patients affected by melanoma, Hodgkin's lymphoma, Merkel cell carcinoma, and head and neck, bladder, renal cell or non-small cell lung cancer is way beyond the most optimistic expectation. However, immune checkpoint blockade (ICB) has failed to arrest progression in a consistent amount of patients affected by those tumors, and various histological types, including breast, colon and prostate cancer, are less sensitive to this therapeutic approach. Such clinical findings have fueled massive research efforts in the attempt to identify pre-existing and acquired mechanisms of resistance to ICB. Here we focus on evidences emerging from studies in humans on how tumor cells and the tumor microenvironment contribute to the heterogeneous clinical responses, and we propose strategies stemming from pre-clinical models that might improve clinical outcomes for patients.

Leukocyte trafficking in tumor microenvironment

The tumor microenvironment consists of both malignant and non-malignant cells and a plethora of soluble mediators. Different types of tumors have specific tumor microenvironments characterized by distinct chemokines and chemotactic factors that influence leukocyte recruitment. The immune cell infiltrate continuously interacts with stroma cells and influence tumor growth. Emerging evidence suggests that the regulation of the composition and the metabolic state of tumor-associated leukocytes may represent a new promising intervention strategy. Here we summarize the current knowledge on the role of tumor-associated immune cells in tumor growth and dissemination, with a specific focus on the nature of the chemotactic factors responsible for their accumulation and activation in tumors.

Tumor Interferon Signaling Regulates a Multigenic Resistance Program to Immune Checkpoint Blockade

Therapeutic blocking of the PD1 pathway results in significant tumor responses, but resistance is common. We demonstrate that prolonged interferon signaling orchestrates PDL1-dependent and PDL1-independent resistance to immune checkpoint blockade (ICB) and to combinations such as radiation plus anti-CTLA4. Persistent type II interferon signaling allows tumors to acquire STAT1-related epigenomic changes and augments expression of interferon-stimulated genes and ligands for multiple T cell inhibitory receptors. Both type I and II interferons maintain this resistance program. Crippling the program genetically or pharmacologically interferes with multiple inhibitory pathways and expands distinct T cell populations with improved function despite expressing markers of severe exhaustion. Consequently, tumors resistant to multi-agent ICB are rendered responsive to ICB monotherapy. Finally, we observe that biomarkers for interferon-driven resistance associate with clinical progression after anti-PD1 therapy. Thus, the duration of tumor interferon signaling augments adaptive resistance and inhibition of the interferon response bypasses requirements for combinatorial ICB therapies.

Twelve-year survival and immune correlates in dendritic cell-vaccinated melanoma patients

BACKGROUND

Reports on long-term (≥10 years) effects of cancer vaccines are missing. Therefore, in 2002, we initiated a phase I/II trial in cutaneous melanoma patients to further explore the immunogenicity of our DC vaccine and to establish its long-term toxicity and clinical benefit after a planned 10-year followup.

METHODS

Monocyte-derived DCs matured by TNFα, IL-1β, IL-6, and PGE2 and then loaded with 4 HLA class I and 6 class II-restricted tumor peptides were injected intradermally in high doses over 2 years. We performed serial immunomonitoring in all 53 evaluable patients.

RESULTS

Vaccine-specific immune responses including high-affinity, IFNγ-producing CD4+ and lytic polyfunctional CD8+ T cells were de novo induced or boosted in most patients. Exposure of mature DCs to trimeric soluble CD40 ligand, unexpectedly, did not further enhance such immune responses, while keyhole limpet hemocyanin (KLH) pulsing to provide unspecific CD4+ help promoted CD8+ T cell responses - notably, their longevity. An unexpected 19% of nonresectable metastatic melanoma patients are still alive after 11 years, a survival rate similar to that observed in ipilimumab-treated patients and achieved without any major (>grade 2) toxicity. Survival correlated significantly with the development of intense vaccine injection site reactions, and with blood eosinophilia after the first series of vaccinations, suggesting that prolonged survival was a consequence of DC vaccination.

CONCLUSIONS

Long-term survival in advanced melanoma patients undergoing DC vaccination is similar to ipilimumab-treated patients and occurs upon induction of tumor-specific T cells, blood eosinophilia, and strong vaccine injection site reactions occurring after the initial vaccinations.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00053391.

FUNDING

European Community, Sixth Framework Programme (Cancerimmunotherapy LSHC-CT-2006-518234; DC-THERA LSHB-CT-2004-512074), and German Research Foundation (CRC 643, C1, Z2).

Impact of Metabolism on T-Cell Differentiation and Function and Cross Talk with Tumor Microenvironment

The immune system and metabolism are highly integrated and multilevel interactions between metabolic system and T lymphocyte signaling and fate exist. Accumulating evidence indicates that the regulation of nutrient uptake and utilization in T cells is critically important for the control of their differentiation and manipulating metabolic pathways in these cells can shape their function and survival. This review will discuss some potential cell metabolism pathways involved in shaping T lymphocyte function and differentiation. It will also describe show subsets of T cells have specific metabolic requirements and signaling pathways that contribute to their respective function. Examples showing the apparent similarity between cancer cell metabolism and T cells during activation are illustrated and finally some mechanisms being used by tumor microenvironment to orchestrate T-cell metabolic dysregulation and the subsequent emergence of immune suppression are discussed. We believe that targeting T-cell metabolism may provide an additional opportunity to manipulate T-cell function in the development of novel therapeutics.

Talimogene Laherparepvec (T-VEC) and Other Oncolytic Viruses for the Treatment of Melanoma

Many mammalian viruses have properties that can be commandeered for the treatment of cancer. These characteristics include preferential infection and replication in tumor cells, the initiation of tumor cell lysis, and the induction of innate and adaptive anti-tumor immunity. Furthermore, viruses can be genetically engineered to reduce pathogenicity and increase immunogenicity resulting in minimally toxic therapeutic agents. Talimogene laherparepvec (T-VEC; Imlygic™), is a genetically modified herpes simplex virus, type 1, and is the first oncolytic virus therapy to be approved for the treatment of advanced melanoma by the US FDA. T-VEC is attenuated by the deletion of the herpes neurovirulence viral genes and enhanced for immunogenicity by the deletion of the viral ICP47 gene. Immunogenicity is further supported by expression of the human granulocyte-macrophage colony-stimulating factor (GM-CSF) gene, which helps promote the priming of T cell responses. T-VEC demonstrated significant improvement in durable response rate, objective response rate, and progression-free survival in a randomized phase III clinical trial for patients with advanced melanoma. This review will discuss the optimal selection of patients for such treatment and describe how therapy is optimally delivered. We will also discuss future directions for oncolytic virus immunotherapy, which will likely include combination T-VEC clinical trials, expansion of T-VEC to other types of non-melanoma skin cancers, and renewed efforts at oncolytic virus drug development with other viruses.

Pathogen boosted adoptive cell transfer immunotherapy to treat solid tumors

Because of insufficient migration and antitumor function of transferred T cells, especially inside the immunosuppressive tumor microenvironment (TME), the efficacy of adoptive cell transfer (ACT) is much curtailed in treating solid tumors. To overcome these challenges, we sought to reenergize ACT (ReACT) with a pathogen-based cancer vaccine. To bridge ACT with a pathogen, we genetically engineered tumor-specific CD8 T cells in vitro with a second T-cell receptor (TCR) that recognizes a bacterial antigen. We then transferred these dual-specific T cells in combination with intratumoral bacteria injection to treat solid tumors in mice. The dual-specific CD8 T cells expanded vigorously, migrated to tumor sites, and robustly eradicated primary tumors. The mice cured from ReACT also developed immunological memory against tumor rechallenge. Mechanistically, we have found that this combined approach reverts the immunosuppressive TME and recruits CD8 T cells with an increased number and killing ability to the tumors.

Adaptive Resistance to Cancer Immunotherapy

Immunosuppressive mechanisms within the tumor microenvironment have emerged as a major impediment to cancer immunotherapy. While a broad range of secreted factors, receptors/ligands, and cell populations have been described that contribute to the immunosuppression, the involvement of these processes in immune evasion by tumors is typically considered to be an intrinsic property of the tumor. Evidence is now emerging that the processes underlying immune suppression within the tumor are, in fact, triggered by immune attack and reflect a dynamic interplay between the tumor and the host's immune system. The term adaptive resistance has been coined to describe the induction of immune suppressive pathways in the tumor following active attack on the tumor. Adaptive resistance is a scalable process where the magnitude of immune suppression matches the magnitude of the immune attack; the net balance between suppression and attack determines the durability of the anti-tumor response and tumor outcome. In this chapter, we will examine the data supporting adaptive resistance and the opposing roles of T cells in simultaneously promoting both anti-tumor immunity and immune suppression within the tumor microenvironment. The clinical implications of adaptive resistance in the design and application of immunotherapeutic strategies is also discussed.

Dysregulation of Chemokine/Chemokine Receptor Axes and NK Cell Tissue Localization during Diseases

Chemokines are small chemotactic molecules that play key roles in physiological and pathological conditions. Upon signaling via their specific receptors, chemokines regulate tissue mobilization and trafficking of a wide array of immune cells, including natural killer (NK) cells. Current research is focused on analyzing changes in chemokine/chemokine receptor expression during various diseases to interfere with pathological trafficking of cells or to recruit selected cell types to specific tissues. NK cells are a heterogeneous lymphocyte population comprising several subsets endowed with distinct functional properties and mainly representing distinct stages of a linear development process. Because of their different functional potential, the type of subset that accumulates in a tissue drives the final outcome of NK cell-regulated immune response, leading to either protection or pathology. Correspondingly, chemokine receptors, including CXCR4, CXCR3, and CX₃CR1, are differentially expressed by NK cell subsets, and their expression levels can be modulated during NK cell activation. At first, this review will summarize the current knowledge on the contribution of chemokines to the localization and generation of NK cell subsets in homeostasis. How an inappropriate chemotactic response can lead to pathology and how chemokine targeting can therapeutically affect tissue recruitment/localization of distinct NK cell subsets will also be discussed.

Interferons and the Immunogenic Effects of Cancer Therapy

Much of our understanding on resistance mechanisms to conventional cancer therapies such as chemotherapy and radiation has focused on cell intrinsic properties that antagonize the detrimental effects of DNA and other cellular damage. However, it is becoming clear that the immune system and/or innate immune signaling pathways can integrate with these intrinsic mechanisms to profoundly influence treatment efficacy. In this context, recent evidence indicates that interferon (IFN) signaling has an important role in this integration by influencing immune and intrinsic/non-immune determinants of therapy response. However, IFN signaling can be both immunostimulatory and immunosuppressive, and the factors determining these outcomes in different disease settings are unclear. Here I discuss the regulation and molecular events in cancer that are associated with these dichotomous functions.

Intratumoral interferon-gamma increases chemokine production but fails to increase T cell infiltration of human melanoma metastases

INTRODUCTION

Optimal approaches to induce T cell infiltration of tumors are not known. Chemokines CXCL9, CXCL10, and CXCL11 support effector T cell recruitment and may be induced by IFN. This study tests the hypothesis that intratumoral administration of IFNγ will induce CXCL9-11 and will induce T cell recruitment and anti-tumor immune signatures in melanoma metastases.

PATIENTS AND METHODS

Nine eligible patients were immunized with a vaccine comprised of 12 class I MHC-restricted melanoma peptides and received IFNγ intratumorally. Effects on the tumor microenvironment were evaluated in sequential tumor biopsies. Adverse events (AEs) were recorded. T cell responses to vaccination were assessed in PBMC by IFNγ ELISPOT assay. Tumor biopsies were evaluated for immune cell infiltration, chemokine protein expression, and gene expression.

RESULTS

Vaccination and intratumoral administration of IFNγ were well tolerated. Circulating T cell responses to vaccine were detected in six of nine patients. IFNγ increased production of chemokines CXCL10, CXCL11, and CCL5 in patient tumors. Neither vaccination alone, nor the addition of IFNγ promoted immune cell infiltration or induced anti-tumor immune gene signatures.

CONCLUSION

The melanoma vaccine induced circulating T cell responses, but it failed to infiltrate metastases, thus highlighting the need for combination strategies to support T cell infiltration. A single intratumoral injection of IFNγ induced T cell-attracting chemokines; however, it also induced secondary immune regulation that may paradoxically limit immune infiltration and effector functions. Alternate dosing strategies or additional combinatorial treatments may be needed to promote trafficking and retention of tumor-reactive T cells in melanoma metastases.

Predictive and prognostic biomarkers of targeted agents and modern immunotherapy in renal cell carcinoma

In the past decade, several agents targeting angiogenesis and signal transduction pathways have replaced the use of cytokines as standard of care treatment for metastatic renal cell carcinoma (RCC) after showing improved clinical benefit and survival. Currently, several novel immunotherapy agents targeting the programmed cell death-1 (PD-1) and cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) pathways are being tested in metastatic RCC and are bound to revolutionise the management of this disease. However, the success of both antiangiogenic drugs and new immunotherapy agents still depends on our ability to select patients most likely to respond to treatment. This article will review the current available evidence on prognostic and predictive biomarkers of response to signal transduction pathways-targeted agents and modern immunotherapy in metastatic RCC.

Immunodynamics: a cancer immunotherapy trials network review of immune monitoring in immuno-oncology clinical trials

The efficacy of PD-1/PD-L1 targeted therapies in addition to anti-CTLA-4 solidifies immunotherapy as a modality to add to the anticancer arsenal. Despite raising the bar of clinical efficacy, immunologically targeted agents raise new challenges to conventional drug development paradigms by highlighting the limited relevance of assessing standard pharmacokinetics (PK) and pharmacodynamics (PD). Specifically, systemic and intratumoral immune effects have not consistently correlated with standard relationships between systemic dose, toxicity, and efficacy for cytotoxic therapies. Hence, PK and PD paradigms remain inadequate to guide the selection of doses and schedules, both starting and recommended Phase 2 for immunotherapies. The promise of harnessing the immune response against cancer must also be considered in light of unique and potentially serious toxicities. Refining immune endpoints to better inform clinical trial design represents a high priority challenge. The Cancer Immunotherapy Trials Network investigators review the immunodynamic effects of specific classes of immunotherapeutic agents to focus immune assessment modalities and sites, both systemic and importantly intratumoral, which are critical to the success of the rapidly growing field of immuno-oncology.

Histone deacetylase inhibitors as immunomodulators in cancer therapeutics

HDAC inhibitors (HDACIs) are anticancer agents being developed in preclinical and clinical settings due to their capacity to modulate gene expression involved in cell growth, differentiation and apoptosis, through modification of both chromatin histone and nonhistone proteins. Most HDACIs in clinical development have cytotoxic or cytostatic properties and their direct inhibitory effects on tumor cells are well documented. Numerous studies have revealed that HDACIs have potent immunomodulatory activity in tumor-bearing animals and cancer patients, providing guidance to apply these agents in cancer immunotherapies. Here, we summarize recent reports addressing the effects of HDACIs on tumor cell immunogenicity, and on different components of the host immune system. In addition, we discuss the complexity of the immunomodulatory activity of these agents, which depends on the class specificity of the HDACIs, different experimental settings and the target immune cell populations.

Epithelial-Mesenchymal Transition Is Associated with a Distinct Tumor Microenvironment Including Elevation of Inflammatory Signals and Multiple Immune Checkpoints in Lung Adenocarcinoma

PURPOSE

Promising results in the treatment of non-small cell lung cancer (NSCLC) have been seen with agents targeting immune checkpoints, such as programmed cell death 1 (PD-1) or programmed death ligand-1 (PD-L1). However, only a select group of patients respond to these interventions. The identification of biomarkers that predict clinical benefit to immune checkpoint blockade is critical to successful clinical translation of these agents.

METHODS

We conducted an integrated analysis of three independent large datasets, including The Cancer Genome Atlas of lung adenocarcinoma and two datasets from MD Anderson Cancer Center (Houston, TX), Profiling of Resistance Patterns and Oncogenic Signaling Pathways in Evaluation of Cancers of the Thorax (named PROSPECT) and Biomarker-Integrated Approaches of Targeted Therapy for Lung Cancer Elimination (named BATTLE-1). Comprehensive analysis of mRNA gene expression, reverse-phase protein array, IHC, and correlation with clinical data were performed.

RESULTS

Epithelial-mesenchymal transition (EMT) is highly associated with an inflammatory tumor microenvironment in lung adenocarcinoma, independent of tumor mutational burden. We found immune activation coexistent with elevation of multiple targetable immune checkpoint molecules, including PD-L1, PD-L2, PD-1, TIM-3, B7-H3, BTLA, and CTLA-4, along with increases in tumor infiltration by CD4(+)Foxp3(+) regulatory T cells in lung adenocarcinomas that displayed an EMT phenotype. Furthermore, we identify B7-H3 as a prognostic marker for NSCLC.

CONCLUSIONS

The strong association between EMT status and an inflammatory tumor microenvironment with elevation of multiple targetable immune checkpoint molecules warrants further investigation of using EMT as a predictive biomarker for immune checkpoint blockade agents and other immunotherapies in NSCLC and possibly a broad range of other cancers. Clin Cancer Res; 22(14); 3630-42. ©2016 AACRSee related commentary by Datar and Schalper, p. 3422.

Semi-solid tumor model in Xenopus laevis/gilli cloned tadpoles for intravital study of neovascularization, immune cells and melanophore infiltration

Tumors have the ability to grow as a self-sustaining entity within the body. This autonomy is in part accomplished by the tumor cells ability to induce the formation of new blood vessels (angiogenesis) and by controlling cell trafficking inside the tumor mass. These abilities greatly reduce the efficacy of many cancer therapies and pose challenges for the development of more effective cancer treatments. Hence, there is a need for animal models suitable for direct microscopy observation of blood vessel formation and cell trafficking, especially during early stages of tumor establishment. Here, we have developed a reliable and cost effective tumor model system in tadpoles of the amphibian Xenopus laevis. Tadpoles are ideally suited for direct microscopy observation because of their small size and transparency. Using the thymic lymphoid tumor line 15/0 derived from, and transplantable into, the X. laevis/gilli isogenic clone LG-15, we have adapted a system that consists in transplanting 15/0 tumor cells embedded into rat collagen under the dorsal skin of LG-15 tadpole recipients. This system recapitulates many facets of mammalian tumorigenesis and permits real time visualization of the active formation of the tumor microenvironment induced by 15/0 tumor cells including neovascularization, collagen rearrangements as well as infiltration of immune cells and melanophores.