CCL3 augments tumor rejection and enhances CD8+ T cell infiltration through NK and CD103+ dendritic cell recruitment via IFNγ

Investigating Serum and Tissue Expression Identified a Cytokine/Chemokine Signature as a Highly Effective Melanoma Marker

Simple Summary

In this study, we investigated the expression of 27 cytokines/chemokines in the serum of 232 individuals (136 melanoma patients vs. 96 controls). It identified several cytokines/chemokines differently expressed in melanoma patients as compared to the healthy controls, as a function of the presence of the melanoma, age, tumor thickness, and gender, indicating different systemic responses to the melanoma presence. We also analyzed the gene expression of the same 27 molecules at the tissue level in 511 individuals (melanoma patients vs. controls). From the gene expression analysis, we identified several cytokines/chemokines showing strongly different expression in melanoma as compared to the controls, and the 4-gene signature “IL-1Ra, IL-7, MIP-1a, and MIP-1b” as the best combination to discriminate melanoma samples from the controls, with an extremely high accuracy (AUC = 0.98). These data indicate the molecular mechanisms underlying melanoma setup and the relevant markers potentially useful to help the diagnosis of biopsy samples.

Abstract

The identification of reliable and quantitative melanoma biomarkers may help an early diagnosis and may directly affect melanoma mortality and morbidity. The aim of the present study was to identify effective biomarkers by investigating the expression of 27 cytokines/chemokines in melanoma compared to healthy controls, both in serum and in tissue samples. Serum samples were from 232 patients recruited at the IDI-IRCCS hospital. Expression was quantified by xMAP technology, on 27 cytokines/chemokines, compared to the control sera. RNA expression data of the same 27 molecules were obtained from 511 melanoma- and healthy-tissue samples, from the GENT2 database. Statistical analysis involved a 3-step approach: analysis of the single-molecules by Mann–Whitney analysis; analysis of paired-molecules by Pearson correlation; and profile analysis by the machine learning algorithm Support Vector Machine (SVM). Single-molecule analysis of serum expression identified IL-1b, IL-6, IP-10, PDGF-BB, and RANTES differently expressed in melanoma (p < 0.05). Expression of IL-8, GM-CSF, MCP-1, and TNF-α was found to be significantly correlated with Breslow thickness. Eotaxin and MCP-1 were found differentially expressed in male vs. female patients. Tissue expression analysis identified very effective marker/predictor genes, namely, IL-1Ra, IL-7, MIP-1a, and MIP-1b, with individual AUC values of 0.88, 0.86, 0.93, 0.87, respectively. SVM analysis of the tissue expression data identified the combination of these four molecules as the most effective signature to discriminate melanoma patients (AUC = 0.98). Validation, using the GEPIA2 database on an additional 1019 independent samples, fully confirmed these observations. The present study demonstrates, for the first time, that the IL-1Ra, IL-7, MIP-1a, and MIP-1b gene signature discriminates melanoma from control tissues with extremely high efficacy. We therefore propose this 4-molecule combination as an effective melanoma marker.

Targeted Delivery of CXCL9 and OX40L by Mesenchymal Stem Cells Elicits Potent Antitumor Immunity

Major obstacles in immunotherapies include toxicities associated with systemic administration of therapeutic agents, as well as low tumor lymphocyte infiltration that hampers the efficacies. In this study, we report a mesenchymal stem cell (MSC)-based immunotherapeutic strategy in which MSCs specifically deliver T/natural killer (NK) cell-targeting chemokine CXCL9 and immunostimulatory factor OX40 ligand (OX40L)/tumor necrosis factor superfamily member 4 (TNFSF4) to tumor sites in syngeneic subcutaneous and azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced spontaneous colon cancer mouse models. This approach generated potent local antitumor immunity by increasing the ratios of tumor-infiltrating CD8⁺ T and NK cells and production of antitumor cytokines and cytolytic proteins in the tumor microenvironment. Moreover, it improved the efficacy of programmed death-1 (PD-1) blockade in a syngeneic mouse model and significantly suppressed the growth of major histocompatibility complex class I (MHC class I)-deficient tumors. Our MSC-based immunotherapeutic strategy simultaneously recruits and activates immune effector cells at the tumor site, thus overcoming the problems with toxicities of systemic therapeutic agents and low lymphocyte infiltration of solid tumors.

The M1/M2 spectrum and plasticity of malignant pleural effusion-macrophage in advanced lung cancer

BACKGROUND

Malignant pleural effusion (MPE)-macrophage (Mφ) of lung cancer patients within unique M1/M2 spectrum showed plasticity in M1-M2 transition. The M1/M2 features of MPE-Mφ and their significance to patient outcomes need to be clarified; furthermore, whether M1-repolarization could benefit treatment remains unclear.

METHODS

Total 147 stage-IV lung adenocarcinoma patients undergoing MPE drainage were enrolled for profiling and validation of their M1/M2 spectrum. In addition, the MPE-Mφ signature on overall patient survival was analyzed. The impact of the M1-polarization strategy of patient-derived MPE-Mφ on anti-cancer activity was examined.

RESULTS

We found that MPE-Mφ expressed both traditional M1 (HLA-DRA) and M2 (CD163) markers and showed a wide range of M1/M2 spectrum. Most of the MPE-Mφ displayed diverse PD-L1 expression patterns, while the low PD-L1 expression group was correlated with higher levels of IL-10. Among these markers, we identified a novel two-gene MPE-Mφ signature, IL-1β and TGF-β1, representing the M1/M2 tendency, which showed a strong predictive power in patient outcomes in our MPE-Mφ patient cohort (N = 60, p = 0.013) and The Cancer Genome Atlas Lung Adenocarcinoma dataset (N = 478, p < 0.0001). Significantly, β-glucan worked synergistically with IFN-γ to reverse the risk signature by repolarizing the MPE-Mφ toward the M1 pattern, enhancing anti-cancer activity.

CONCLUSIONS

We identified MPE-Mφ on the M1/M2 spectrum and plasticity and described a two-gene M1/M2 signature that could predict the outcome of late-stage lung cancer patients. In addition, we found that "re-education" of these MPE-Mφ toward anti-cancer M1 macrophages using clinically applicable strategies may overcome tumor immune escape and benefit anti-cancer therapies.

Head-to-head comparison of in-house produced CD19 CAR-T cell in ALL and NHL patients

Background

CD19 chimeric antigen receptor T (CAR-T) cells demonstrate remarkable remission rates in pediatric and adult patients with refractory or relapsed (r/r) acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL). In 2016, we initiated a clinical trial with in-house produced CD19 CAR-T cells with a CD28 co-stimulatory domain. We analyzed, for the first time, differences in production features and phenotype between ALL and NHL patients.

Methods

Non-cryopreserved CAR-T cells were produced from patients’ peripheral blood mononuclear cells within 9 to 10 days. 93 patients with r/r ALL and NHL were enrolled under the same study. CAR-T cells of ALL and NHL patients were produced simultaneously, allowing the head-to-head comparison.

Results

All patients were heavily pretreated. Three patients dropped out from the study due to clinical deterioration (n=2) or production failure (n=1). Cells of ALL patients (n=37) expanded significantly better and contained more CAR-T cells than of NHL patients (n=53). Young age had a positive impact on the proliferation capacity. The infusion products from ALL patients contained significantly more naïve CAR-T cells and a significantly higher expression of the chemokine receptor CXCR3. PD-1, LAG-3, TIM-3, and CD28 were equally expressed. 100% of ALL patients and 94% of NHL patients received the target dose of 1×10e6 CAR-T/kg. The overall response rate was 84% (30/36) in ALL and 62% (32/52) in NHL. We further compared CAR-T cell infusion products to tumor infiltrating lymphocytes (TIL), another common type of T cell therapy, mainly clinically effective in solid tumors. CAR-T cells contained significantly more naïve T cells and central memory T cells and significantly less CCR5 compared to TIL infusion products.

Conclusions

The in-house production of CAR-T cells is highly efficient and fast. Clinical response rate is high. CAR-T cells can be successfully produced for 99% of patients in just 9 to 10 days. Cells derived from ALL patients demonstrate a higher proliferation rate and contain higher frequencies of CAR-T cells and naïve T cells than of NHL patients. In addition, understanding the differences between CAR-T and TIL infusion products, may provide an angle to develop CAR-T cells for the treatment of solid tumors in the future.

Trial registration number

ClinicalTrials.gov; CAR-T: NCT02772198, First posted: May 13, 2016; TIL: NCT00287131, First posted: February 6, 2006.

CD4+ and CD8+ cell populations in HIV-positive women with cervical squamous intra-epithelial lesions and squamous cell carcinoma

INTRODUCTION

This study aimed to analyse cervical lymphocytic populations in HIV+ and HIV- patients and correlate different cervical lesions with HIV viral load and presence of high-risk HPV types.

MATERIAL AND METHODS

A total of 132 histological specimens from 40 HIV+ and 72 HIV- patients were evaluated for CD4⁺ and CD8⁺ T cell distribution, presence of high-risk HPV types, peripheral blood HIV viral load and CD4⁺/CD8⁺ ratio.

RESULTS

High-grade squamous intraepithelial lesions (HSIL) and squamous cell carcinoma (SCC) from HIV+ patients had lower CD4⁺ T cell scores compared with HIV- patients. In all lesion groups, HIV+ patients presented higher epithelial and stromal CD8⁺ T cell scores. HIV viral load was more often detectable in patients with SCC than in those with low-grade squamous intraepithelial lesion (LSIL) (p = 0.0409). HSIL HIV+ patients had lower circulating CD4⁺ T cell counts (p = 0.0434) and CD4⁺/CD8⁺ ratio (p = 0.0378) compared with LSIL HIV+ patients. High-risk HPV types other than 16 and 18/45 were more prevalent in the HIV+ group.

DISCUSSION

These results support an imbalance between cervical CD4⁺ and CD8⁺ T lymphocytes of HIV+ patients with SIL and SCC, with increased CD8+ infiltrate density with lesion severity, even in patients with immune system recovery under cART.

A cell-of-origin epigenetic tracer reveals clinically distinct subtypes of high-grade serous ovarian cancer

BACKGROUND

High-grade serous ovarian cancer (HGSOC) is a major unmet need in oncology. The remaining uncertainty on its originating tissue has hampered the discovery of molecular oncogenic pathways and the development of effective therapies.

METHODS

We used an approach based on the retention in tumors of a DNA methylation trace (OriPrint) that distinguishes the two putative tissues of origin of HGSOC, the fimbrial (FI) and ovarian surface epithelia (OSE), to stratify HGSOC by several clustering methods, both linear and non-linear. The identified tumor subtypes (FI-like and OSE-like HGSOC) were investigated at the RNAseq level to stratify an in-house cohort of macrodissected HGSOC FFPE samples to derive overall and disease-free survival and identify specific transcriptional alterations of the two tumor subtypes, both by classical differential expression and weighted correlation network analysis. We translated our strategy to published datasets and verified the co-occurrence of previously described molecular classification of HGSOC. We performed cytokine analysis coupled to immune phenotyping to verify alterations in the immune compartment associated with HGSOC. We identified genes that are both differentially expressed and methylated in the two tumor subtypes, concentrating on PAX8 as a bona fide marker of FI-like HGSOC.

RESULTS

We show that: - OriPrint is a robust DNA methylation tracer that exposes the tissue of origin of HGSOC. - The tissue of origin of HGSOC is the main determinant of DNA methylation variance in HGSOC. - The tissue of origin is a prognostic factor for HGSOC patients. - FI-like and OSE-like HGSOC are endowed with specific transcriptional alterations that impact patients' prognosis. - OSE-like tumors present a more invasive and immunomodulatory phenotype, compatible with its worse prognostic impact. - Among genes that are differentially expressed and regulated in FI-like and OSE-like HGSOC, PAX8 is a bona fide marker of FI-like tumors.

CONCLUSIONS

Through an integrated approach, our work demonstrates that both FI and OSE are possible origins for human HGSOC, whose derived subtypes are both molecularly and clinically distinct. These results will help define a new roadmap towards rational, subtype-specific therapeutic inroads and improved patients' care.

Multidirectional Strategies for Targeted Delivery of Oncolytic Viruses by Tumor Infiltrating Immune Cells

Oncolytic virus (OV) immunotherapy has demonstrated to be a promising approach in cancer treatment due to tumor-specific oncolysis. However, their clinical use so far has been largely limited due to the lack of suitable delivery strategies with high efficacy. Direct 'intratumoral' injection is the way to cross the hurdles of systemic toxicity, while providing local effects. Progress in this field has enabled the development of alternative way using 'systemic' oncolytic virotherapy for producing better results. One major potential roadblock to systemic OV delivery is the low virus persistence in the face of hostile immune system. The delivery challenge is even greater when attempting to target the oncolytic viruses into the entire tumor mass, where not all tumor cells are equally exposed to exactly the same microenvironment. The microenvironment of many tumors is known to be massively infiltrated with various types of leucocytes in both primary and metastatic sites. Interestingly, this intratumoral immune cell heterogeneity exhibits a degree of organized distribution inside the tumor bed as evidenced, for example, by the hypoxic tumor microenviroment where predominantly recruits tumor-associated macrophages. Although in vivo OV delivery seems complicated and challenging, recent results are encouraging for decreasing the limitations of systemically administered oncolytic viruses and an improved efficiency of oncolytic viral therapy in targeting cancerous tissues in vitro. Here, we review the latest developments of carrier cell-based oncolytic virus delivery using tumor-infiltrating immune cells with a focus on the main features of each cellular vehicle.

Nanoformulation of CCL21 greatly increases its effectiveness as an immunotherapy for neuroblastoma

Neuroblastoma is the most commonly diagnosed extracranial solid tumor in children. The patients with aggressive metastatic disease or refractory/relapsed neuroblastoma currently face a dismally low chance of survival. Thus, there is a great need for more effective therapies for this illness. In previous studies, we, as well as others, showed that the immune cell chemoattractant C-C motif chemokine ligand 21 (CCL21) is effective as an intratumoral therapy able to slow the growth of cancers. In this current study, we developed and tested an injectable, slow-release, uniform, and optimally loaded alginate nanoformulation of CCL21 as a means to provide prolonged intratumoral treatment. The alginate-nanoformulated CCL21, when injected intratumorally into mice bearing neuroblastoma lesions, significantly prolonged survival and decreased the tumor growth rate compared to CCL21 alone, empty nanoparticles, or buffer. Notably, we also observed complete tumor clearance and subsequent full protection against tumor rechallenge in 33% of nanoformulated CCL21-treated mice. Greater intratumoral presence of nanoformulated CCL21, compared to free CCL21, at days 1 and 2 after treatment ended was confirmed through fluorescent labeling and tracking. Nanoformulated CCL21-treated tumors exhibited a general pattern of prolonged increases in anti-tumor cytokines and relatively lower levels of pro-tumor cytokines in comparison to tumors treated with CCL21 alone or buffer only. Thus, this novel nanoformulation of CCL21 is an effective treatment for neuroblastoma, and may have potential for the delivery of CCL21 to other types of solid tumors in the future and as a slow-release delivery modality for other immunotherapies.

Suppressor of cytokine signaling 1 inhibits the maturation of dendritic cells involving the nuclear factor kappa B signaling pathway in the glioma microenvironment

Recurrence and diffuse infiltration challenge traditional therapeutic strategies for malignant glioma. Immunotherapy appears to be a promising approach to obtain long-term survival. Dendritic cells (DCs), the most specialized and potent antigen-presenting cells (APCs), play an important part in initiating and amplifying both the innate and adaptive immune responses against cancer cells. However, cancer cells can escape from immune surveillance by inhibiting maturation of DCs. Until the present, molecular mechanisms of maturation inhibition of DCs in the tumor microenvironment (TME) have not been fully revealed. Our study showed that pretreatment with tumor-conditioned medium (TCM) collected from supernatant of primary glioma cells significantly suppressed the maturation of DCs. TCM pretreatment significantly changed the morphology of DCs, TCM decreased the expression levels of CD80, CD83, CD86 and interleukin (IL)-12p70, while it increased the expression levels of IL-10, transforming growth factor (TGF)-β and IL-6. RNA-Seq showed that TCM pretreatment significantly increased the gene expression level of suppressor of cytokine signaling 1 (SOCS1) in DCs. suppressor of cytokine signaling 1 (SOCS1) knock-down significantly antagonized the maturation inhibition of DCs by TCM, which was demonstrated by the restoration of maturation markers. TCM pretreatment also significantly suppressed T cell viability and T helper type 1 (Th1) response, and SOCS1 knock-down significantly antagonized this suppressive effect. Further, TCM pretreatment significantly suppressed p65 nuclear translocation and transcriptional activity in DCs, and SOCS1 knock-down significantly attenuated this suppressive effect. In conclusion, our research demonstrates that TCM up-regulate SOCS1 to suppress the maturation of DCs via the nuclear factor-kappa signaling pathway.

Emerging role of PTEN loss in evasion of the immune response to tumours

Mutations in PTEN activate the phosphoinositide 3-kinase (PI3K) signalling network, leading to many of the characteristic phenotypic changes of cancer. However, the primary effects of this gene on oncogenesis through control of the PI3K-AKT-mammalian target of rapamycin (mTOR) pathway might not be the only avenue by which PTEN affects tumour progression. PTEN has been shown to regulate the antiviral interferon network and thus alter how cancer cells communicate with and are targeted by immune cells. An active, T cell-infiltrated microenvironment is critical for immunotherapy success, which is also influenced by mutations in DNA damage repair pathways and the overall mutational burden of the tumour. As PTEN has a role in the maintenance of genomic integrity, it is likely that a loss of PTEN affects the immune response at two different levels and might therefore be instrumental in mediating failed responses to immunotherapy. In this review, we summarise findings that demonstrate how the loss of PTEN function elicits specific changes in the immune response in several types of cancer. We also discuss ongoing clinical trials that illustrate the potential utility of PTEN as a predictive biomarker for immune checkpoint blockade therapies.

Immunostimulatory oncolytic virotherapy for multiple myeloma targeting 4-1BB and/or CD40

Multiple myeloma (MM) is a plasma cell malignancy that is characterized by immune dysregulation. MM is commonly treated with immunomodulating agents, but still remains incurable. Herein, we proposed and evaluated immunostimulatory Lokon oncolytic adenoviruses (LOAd) for MM treatment. LOAd viruses are serotype 5/35 chimera, which enables infection of hematopoietic cells. Oncolysis is restricted to cells with a dysregulated retinoblastoma protein pathway, which is frequently observed in MM. Further, LOAd viruses are armed with human immunostimulatory transgenes: trimerized membrane-bound CD40L (LOAd700, LOAd703) and 4-1BBL (LOAd703). LOAd viruses were assessed in a panel of MM cell lines (ANBL-6, L363, LP-1, OPM-2, RPMI-8226, and U266-84). All cells were sensitive to infection, leading to viral replication and cell killing as analyzed by quantitative PCR and viability assay. Transgene expression was verified post infection with flow cytometry. Cell phenotypes were further altered with a downregulation of markers connected to MM progression (ICAM-1, CD70, CXCL10, CCL2, and sIL-2Rα) and an upregulation of the death receptor Fas. In a co-culture of immune and MM cells, LOAd viruses promoted activation of cytotoxic T cells as seen by higher CD69, CD107a, and IFNγ expression. This was most prominent with LOAd703. In conclusion, LOAd viruses are of interest for MM therapy.

Chimeric Antigen Receptor Cell Therapy: Overcoming Obstacles to Battle Cancer

Chimeric antigen receptors (CAR) are fusion proteins engineered from antigen recognition, signaling, and costimulatory domains that can be used to reprogram T cells to specifically target tumor cells expressing specific antigens. Current CAR-T cell technology utilizes the patient's own T cells to stably express CARs and has achieved exciting clinical success in the past few years. However, current CAR-T cell therapy still faces several challenges, including suboptimal persistence and potency, impaired trafficking to solid tumors, local immunosuppression within the tumor microenvironment and intrinsic toxicity associated with CAR-T cells. This review focuses on recent strategies to improve the clinical efficacy of CAR-T cell therapy and other exciting CAR approaches currently under investigation, including CAR natural killer (NK) and NKT cell therapies.

Cyto-Immuno-Therapy for Cancer: A Pathway Elicited by Tumor-Targeted, Cytotoxic Drug-Packaged Bacterially Derived Nanocells

Immunotherapy has emerged as a powerful new chapter in the fight against cancer. However, it has yet to reach its full potential due in part to the complexity of the cancer immune response. We demonstrate that tumor-targeting EDV nanocells function as an immunotherapeutic by delivering a cytotoxin in conjunction with activation of the immune system. These nanocells polarize M1 macrophages and activate NK cells concurrently producing a Th1 cytokine response resulting in potent antitumor function. Dendritic cell maturation and antigen presentation follows, which generates tumor-specific CD8⁺ T cells, conferring prolonged tumor remission. The combination of cytotoxin delivery and activation of innate and adaptive antitumor immune responses results in a potent cyto-immunotherapeutic with potential in clinical oncology.

CCL3 Signaling in the Tumor Microenvironment

Within the tumor microenvironment, chemokines play a key role in immune cell trafficking regulation and immune landscape formulation. CCL3 or macrophage inflammatory protein-1α (MIP-1α), an important chemokine implicated in both immune surveillance and tolerance, has emerged as a prognostic biomarker in both solid and hematological malignancies. CCL3 exerts both antitumor and pro-tumor behavior which is context dependent highlighting the complexity of the underlying interrelated signaling cascades. Current CCL3-directed therapeutic approaches are investigational and further optimization is required to increase efficacy and minimize adverse events.

Engineering Targeting Materials for Therapeutic Cancer Vaccines

Therapeutic cancer vaccines constitute a valuable tool to educate the immune system to fight tumors and prevent cancer relapse. Nevertheless, the number of cancer vaccines in the clinic remains very limited to date, highlighting the need for further technology development. Recently, cancer vaccines have been improved by the use of materials, which can strongly enhance their intrinsic properties and biodistribution profile. Moreover, vaccine efficacy and safety can be substantially modulated through selection of the site at which they are delivered, which fosters the engineering of materials capable of targeting cancer vaccines to specific relevant sites, such as within the tumor or within lymphoid organs, to further optimize their immunotherapeutic effects. In this review, we aim to give the reader an overview of principles and current strategies to engineer therapeutic cancer vaccines, with a particular focus on the use of site-specific targeting materials. We will first recall the goal of therapeutic cancer vaccination and the type of immune responses sought upon vaccination, before detailing key components of cancer vaccines. We will then present how materials can be engineered to enhance the vaccine's pharmacokinetic and pharmacodynamic properties. Finally, we will discuss the rationale for site-specific targeting of cancer vaccines and provide examples of current targeting technologies.

Immune Responses Raised in an Experimental Colon Carcinoma Model Following Oral Administration of Lactobacillus casei

The role of dietary probiotic strains on host anticancer immune responses against experimental colon carcinoma was investigated. We have previously shown that Lactobacillus casei administration led to tumor growth suppression in an experimental colon cancer model. Here, we investigated the underlying immune mechanisms involved in this tumorgrowth inhibitory effect. BALB/c mice received daily live lactobacilli per os prior to the establishment of a syngeneic subcutaneous CT26 tumor. Tumor volume, cytokine production, T cell differentiation and migration, as well as tumor cell apoptosis were examined to outline potential immunomodulatory effects following L. casei oral intake. Probiotic administration in mice resulted in a significant increase in interferon gamma (IFNγ), Granzyme B and chemokine production in the tumor tissue as well as enhanced CD8⁺ T cell infiltration, accompanied by a suppression of tumor growth. Cytotoxic activity against cancer cells was enhanced in probioticfed compared to control mice, as evidenced by the elevation of apoptotic markers, such as cleaved caspase 3 and poly (ADPribose) polymerase 1 (PARP1), in tumor tissue. Oral administration of Lactobacillus casei induced potent Th1 immune responses and cytotoxic T cell infiltration in the tumor tissue of tumorbearing mice, resulting in tumor growth inhibition. Thus, the microorganism may hold promise as a novel dietary immunoadjuvant in raising protective anticancer immune responses.

Trial watch: chemotherapy-induced immunogenic cell death in immuno-oncology

The term ‘immunogenic cell death’ (ICD) denotes an immunologically unique type of regulated cell death that enables, rather than suppresses, T cell-driven immune responses that are specific for antigens derived from the dying cells. The ability of ICD to elicit adaptive immunity heavily relies on the immunogenicity of dying cells, implying that such cells must encode and present antigens not covered by central tolerance (antigenicity), and deliver immunostimulatory molecules such as damage-associated molecular patterns and cytokines (adjuvanticity). Moreover, the host immune system must be equipped to detect the antigenicity and adjuvanticity of dying cells. As cancer (but not normal) cells express several antigens not covered by central tolerance, they can be driven into ICD by some therapeutic agents, including (but not limited to) chemotherapeutics of the anthracycline family, oxaliplatin and bortezomib, as well as radiation therapy. In this Trial Watch, we describe current trends in the preclinical and clinical development of ICD-eliciting chemotherapy as partner for immunotherapy, with a focus on trials assessing efficacy in the context of immunomonitoring.

CXCL9 chemokine promotes the progression of human pancreatic adenocarcinoma through STAT3-dependent cytotoxic T lymphocyte suppression

Chemokines play essential roles in the progression of various human cancers; however, the expression and role of CXC chemokines in pancreatic adenocarcinoma (PAAD) have not yet been identified. The aim of this study is to identify the expression patterns, clinical significance and mechanisms of CXC chemokines in regulating tumour microenvironment of PAAD. Three CXC chemokines, including CXCL5, CXCL9, and CXCL10, were significantly overexpressed in PAAD tissues, which were correlated with the poor survival of the patients. CXCL9/10 was associated with change of immune cell pattern in the tumour microenvironment, and supplementation of CXCL9 in the orthotopic murine PAAD model promoted tumour progression. In particular, CXCL9 reduced the CD8+ cytotoxic T lymphocytes in the tumour microenvironment of PAAD, which could be attributed to the reduced CD8+ T cell proliferation, activation, and secretion of anti-tumour cytokines. In vitro treatment of CXCL9 directly led to the suppression of the proliferation, activation, and secretion of anti-tumour cytokines of isolated CD8+ T cells. Inhibition of STAT3 recovered the CXCL9-inhibited proliferation, activation, and secretion of anti-tumour cytokines of CD8+ T cells. Our study indicates CXCL9 as a potential target of immunotherapy in PAAD treatment by regulating the CD8+ T lymphocytes in the tumour microenvironment.

Patrolling Monocytes Control NK Cell Expression of Activating and Stimulatory Receptors to Curtail Lung Metastases

The role of nonclassical, patrolling monocytes in lung tumor metastasis and their functional relationships with other immune cells remain poorly defined. Contributing to these gaps in knowledge is a lack of cellular specificity in commonly used approaches for depleting nonclassical monocytes. To circumvent these limitations and study the role of patrolling monocytes in melanoma metastasis to lungs, we generated C57BL/6J mice in which the Nr4a1 superenhancer E2 subdomain is ablated (E2 -/- mice). E2 -/- mice lack nonclassical patrolling monocytes but preserve classical monocyte and macrophage numbers and functions. Interestingly, NK cell recruitment and activation were impaired, and metastatic burden was increased in E2 -/-mice. E2 -/- mice displayed unchanged "educated" (CD11b+CD27+) and "terminally differentiated" (CD11b+CD27-) NK cell frequencies. These perturbations were accompanied by reduced expression of stimulatory receptor Ly49D on educated NK cells and increased expression of inhibitory receptor NKG2A/CD94 on terminally differentiated NK cells. Thus, our work demonstrates that patrolling monocytes play a critical role in preventing lung tumor metastasis via NK cell recruitment and activation.

Interaction kinetics with transcriptomic and secretory responses of CD19-CAR natural killer-cell therapy in CD20 resistant non-hodgkin lymphoma

We investigated the cytolytic and mechanistic activity of anti-CD19 chimeric antigen receptor natural killer (CD19.CAR.NK92) therapy in lymphoma cell lines (diffuse large B-cell, follicular, and Burkitt lymphoma), including rituximab- and obinutuzumab-resistant cells, patient-derived cells, and a human xenograft model. Altogether, CD19.CAR.NK92 therapy significantly increased cytolytic activity at E:T ratios (1:1–10:1) via LDH release and prominent induction of apoptosis in all cell lines, including in anti-CD20 resistant lymphoma cells. The kinetics of CD19.CAR.NK92 cell death measured via droplet-based single cell microfluidics analysis showed that most lymphoma cells were killed by single contact, with anti-CD20 resistant cell lines requiring significantly longer contact duration with NK cells. Additionally, systems biology transcriptomic analyses of flow-sorted lymphoma cells co-cultured with CD19.CAR.NK92 revealed conserved activation of IFNγ signaling, execution of apoptosis, ligand binding, and immunoregulatory and chemokine signaling pathways. Furthermore, a 92-plex cytokine panel analysis showed increased secretion of granzymes, increased secretion of FASL, CCL3 and IL10 in anti-CD20 resistant SUDHL-4 cells with induction of genes relevant to mTOR and G2/M checkpoint activation were noted in all anti-CD20 resistant cells co-cultured with CD19.CAR.NK92 cells. Collectively, CD19.CAR.NK92 was associated with potent anti-lymphoma activity across a host of sensitive and resistant lymphoma cells that involved distinct immuno-biologic mechanisms.

Senescent hepatocytes enhance natural killer cell activity via the CXCL-10/CXCR3 axis

Cellular senescence and natural killer (NK) cells play an important role in liver diseases. Chemokines, a component of the senescence-associated secretory phenotype, can recruit NK cells and are involved in the development of various liver diseases. The effect of the C-X-C motif chemokine ligand (CXCL)-9, −10, −11/C-X-C motif chemokine receptor (CXCR)3 axis in senescent hepatocytes remains unknown. The chemokines secreted by senescent hepatocytes, the contribution of the CXCL-9, −10, −11/CXCR3 axis to the migration of NK cells, and the effect of senescent hepatocytes on the function of NK cells were investigated in the present study. The results demonstrated significantly increased levels of C-C motif chemokine ligand 2 and CXCL-1, −2 and −10 in the supernatant of senescent AML12 cells. Despite increased mRNA expression of CXCL-9, −10, and −11 in these cells, western blotting revealed significantly enhanced expression of only CXCL-10. The expression of CXCR3 on the surface of NK cells stimulated by senescent AML12 cells was upregulated (fold change, >3). Following incubation with the supernatant of senescent hepatocytes, both CD107a and interferon γ expression in NK cells increased by >2.5-fold. The cytotoxic effect of NK cells was notably higher stimulated by senescent AML12 cells. Chemotaxis and blocking assays demonstrated that the senescent hepatocytes enhanced the migration of NK cells via the CXCL-10/CXCR3 axis. The present study suggests that senescent hepatocytes secrete various chemokines, including CXCL-10, resulting in the upregulation and activation of CXCR3 in NK cells and the enhancement of NK cell migration via the CXCL-10/CXCR3 axis.

Trial watch: dendritic cell vaccination for cancer immunotherapy

Dendritic- cells (DCs) have received considerable attention as potential targets for the development of anticancer vaccines. DC-based anticancer vaccination relies on patient-derived DCs pulsed with a source of tumor-associated antigens (TAAs) in the context of standardized maturation-cocktails, followed by their reinfusion. Extensive evidence has confirmed that DC-based vaccines can generate TAA-specific, cytotoxic T cells. Nonetheless, clinical efficacy of DC-based vaccines remains suboptimal, reflecting the widespread immunosuppression within tumors. Thus, clinical interest is being refocused on DC-based vaccines as combinatorial partners for T cell-targeting immunotherapies. Here, we summarize the most recent preclinical/clinical development of anticancer DC vaccination and discuss future perspectives for DC-based vaccines in immuno-oncology.

PD-1 Blockade Following Isolated Limb Perfusion with Vaccinia Virus Prevents Local and Distant Relapse of Soft-tissue Sarcoma

PURPOSE

The prevention and treatment of metastatic sarcoma are areas of significant unmet need. Immune checkpoint inhibitor monotherapy has shown little activity in sarcoma and there is great interest in identifying novel treatment combinations that may augment responses. In vitro and in vivo, we investigated the potential for an oncolytic vaccinia virus (GLV-1h68) delivered using isolated limb perfusion (ILP) to promote antitumor immune responses and augment response to PD-1 blockade in sarcoma.Experimental Design: In an established animal model of extremity sarcoma, we evaluated the potential of locoregional delivery of a vaccinia virus (GLV-1h68) alongside biochemotherapy (melphalan/TNFα) in ILP. Complementary in vitro assays for markers of immunogenic cell death were performed in sarcoma cell lines.

RESULTS

PD-1 monotherapy had minimal efficacy in vivo, mimicking the clinical scenario. Pretreatment with GLV-1h68 delivered by ILP (viral ILP) significantly improved responses. Furthermore, when performed prior to surgery and radiotherapy, viral ILP and PD-1 blockade prevented both local and distant relapse, curing a previously treatment-refractory model. Enhanced therapy was associated with marked modulation of the tumor microenvironment, with an increase in the number and penetrance of intratumoral CD8+ T cells and expansion and activation of dendritic cells. GLV-1h68 was capable of inducing markers of immunogenic cell death in human sarcoma cell lines.

CONCLUSIONS

Viral ILP augments the response to PD-1 blockade, transforming this locoregional therapy into a potentially effective systemic treatment for sarcoma and warrants translational evaluation.

Reduced T-cell Numbers and Elevated Levels of Immunomodulatory Cytokines in Metastatic Prostate Cancer Patients De Novo Resistant to Abiraterone and/or Enzalutamide Therapy

Currently, there are two Food and Drug Administration (FDA)-approved drugs for androgen deprivation therapy (ADT) of metastatic castration-resistant prostate cancer (mCRPC) patients: abiraterone and enzalutamide. However, our understanding of the effect of these therapies on the immune system in mCRPC patients remains limited. Here, we examined how abiraterone and enzalutamide treatment affects levels of soluble immune mediators in plasma and in circulating immune cells of 44 mCRPC patients. We found that the baseline levels of cytokines fibroblast growth factor (FGF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin 10 (IL-10), and IL-6 were significantly lower in ADT-sensitive compared to de novo resistant patients. In addition, resistant patients showed significantly lower T cell frequencies. When comparing the levels of cytokines over the course of treatment, we observed that the levels of proinflammatory mediators, such as interferon-γ (IFN-γ), IL-5, macrophage inflammatory protein 1 alpha (MIP-1α), and tumor necrosis factor alpha (TNFα), were significantly increased in the ADT-sensitive patients. At the same time, the abiraterone/enzalutamide therapy did not reduce the percentage of tolerogenic myeloid cell populations, such as polymorphonuclear myeloid-derived suppressor cells, which retained unaltered expression of programmed death-ligand 1 (PD-L1) and B7-H3. Overall, our results suggest that certain immune markers, such as IL-6 and the frequency of effector T cells, could be predictive of therapeutic response to ADT therapies in mCRPC patients.

PD-L1 blockade enhances anti-tumor efficacy of NK cells

Anti-PD-1/anti-PD-L1 therapies have shown success in cancer treatment but responses are limited to ~ 15% of patients with lymphocyte infiltrated, PD-L1 positive tumors. Hence, strategies that increase PD-L1 expression and tumor infiltration should make more patients eligible for PD-1/PD-L1 blockade therapy, thus improving overall outcomes. PD-L1 expression on tumors is induced by IFNγ, a cytokine secreted by NK cells. Therefore, we tested if PM21-particle expanded NK cells (PM21-NK cells) induced expression of PD-L1 on tumors and if anti-PD-L1 treatment enhanced NK cell anti-tumor efficacy in an ovarian cancer model. Studies here showed that PM21-NK cells secrete high amounts of IFNγ and that adoptively transferred PM21-NK cells induce PD-L1 expression on SKOV-3 cells in vivo. The induction of PD-L1 expression on SKOV-3 cells coincided with the presence of regulatory T cells (Tregs) in the abdominal cavity and within tumors. In in vitro experiments, anti-PD-L1 treatment had no direct effect on cytotoxicity or cytokine secretion by predominantly PD-1 negative PM21-NK cells in response to PD-L1⁺ targets. However, significant improvement of NK cell anti-tumor efficacy was observed in vivo when combined with anti-PD-L1. PD-L1 blockade also resulted in increased in vivo NK cell persistence and retention of their cytotoxic phenotype. These results support the use of anti-PD-L1 in combination with NK cell therapy regardless of initial tumor PD-L1 status and indicate that NK cell therapy would likely augment the applicability of anti-PD-L1 treatment.

Pharmacologic Depletion of Microglia Increases Viral Load in the Brain and Enhances Mortality in Murine Models of Flavivirus-Induced Encephalitis

Flaviviruses account for most arthropod-borne cases of human encephalitis in the world. However, the exact mechanisms of injury to the central nervous system (CNS) during flavivirus infections remain poorly understood. Microglia are the resident immune cells of the CNS and are important for multiple functions, including control of viral pathogenesis. Utilizing a pharmacologic method of microglia depletion (PLX5622 [Plexxikon Inc.], an inhibitor of colony-stimulating factor 1 receptor), we sought to determine the role of microglia in flaviviral pathogenesis. Depletion of microglia resulted in increased mortality and viral titer in the brain following infection with either West Nile virus (WNV) or Japanese encephalitis virus (JEV). Interestingly, microglial depletion did not prevent virus-induced increases in the expression of relevant cytokines and chemokines at the mRNA level. In fact, the expression of several proinflammatory genes was increased in virus-infected, microglia-depleted mice compared to virus-infected, untreated controls. In contrast, and as expected, expression of the macrophage marker triggering receptor expressed on myeloid cells 2 (TREM2) was decreased in virus-infected, PLX5622-treated mice compared to virus-infected controls.IMPORTANCE As CNS invasion by flaviviruses is a rare but life-threatening event, it is critical to understand how brain-resident immune cells elicit protection or injury during disease progression. Microglia have been shown to be important in viral clearance but may also contribute to CNS injury as part of the neuroinflammatory process. By utilizing a microglial depletion model, we can begin to parse out the exact roles of microglia during flaviviral pathogenesis with hopes of understanding specific mechanisms as potential targets for therapeutics.

T lymphocytes against solid malignancies: winning ways to defeat tumours

In the last decades, a novel field has emerged in the cure of cancer, by boosting the ability of the patient’s immune system to recognize and kill tumour cells. Although excellent and encouraging results, exploiting the effect of genetically modified T cells, have been obtained, it is now evident that tumour malignancies can evolve several mechanisms to escape such immune responses, thus continuing their growth in the body. These mechanisms are in part due to tumour cell metabolic or genetic alterations, which can render the target invisible to the immune system or can favour the generation of an extracellular milieu preventing immune cell infiltration or cytotoxicity. Such mechanisms may also involve the accumulation inside the tumour microenvironment of different immune-suppressive cell types, which further down-regulate the activity of cytotoxic immune cells either directly by interacting with them or indirectly by releasing suppressive molecules. In this review, we will first focus on describing several mechanisms by which tumour cells may dampen or abrogate the immune response inside the tumour microenvironment and, second, on current strategies that are adopted to cope with and possibly overcome such alterations, thus ameliorating the efficacy of the current-in-use anti-cancer immuno-therapies.

Heating it up: Oncolytic viruses make tumors 'hot' and suitable for checkpoint blockade immunotherapies

Immune checkpoint blockade is less efficient in patients bearing immunologically ‘cold’ tumors. Oncolytic viruses, which were originally discovered for their ability to preferentially kill malignant cells, can recondition the tumor microenvironment. Supporting this hypothesis, two new studies published in Science Translational Medicine show that adjuvant-like activities of oncolytic viruses make brain and breast tumors ‘hot’ and sensitize them for subsequent immune checkpoint blockade.