Immune Checkpoint Blockade Immunotherapy Research Articles

Overcoming immunotherapy resistance in NSCLC.

Systemic therapy regimens that contain immune checkpoint blockade immunotherapy, primarily monoclonal antibodies directed against PD-1, PD-L1, or CTLA-4, can induce substantial therapeutic responses in patients with advanced non-small-cell lung cancer (NSCLC). With immune checkpoint blockade, improved survival can be attained for a minority of patients who would otherwise have a poor prognosis; some might even be cured. Key randomised controlled trials have revolutionised the management of newly diagnosed, non-driver mutation-driven NSCLC by showing improved overall survival for regimens containing immune checkpoint inhibitors compared with chemotherapy alone 1 Reck M Rodríguez-Abreu D Robinson AG et al. Updated analysis of KEYNOTE-024: pembrolizumab versus platinum-based chemotherapy for advanced non-small-cell lung cancer with PD-L1 tumor proportion score of 50% or greater. J Clin Oncol. 2019; 37: 537-546 Google Scholar , 2 Gadgeel S Rodríguez-Abreu D Speranza G et al. Updated analysis from KEYNOTE-189: pembrolizumab or placebo plus pemetrexed and platinum for previously untreated metastatic nonsquamous non-small-cell lung cancer. J Clin Oncol. 2020; 38: 1505-1517 Google Scholar , 3 Paz-Ares L Vicente D Tafreshi A et al. A randomized, placebo-controlled trial of pembrolizumab plus chemotherapy in patients with metastatic squamous NSCLC: protocol-specified final analysis of KEYNOTE-407. J Thorac Oncol. 2020; 15: 1657-1669 Google Scholar and for immunotherapy with a PD-1 inhibitor plus a CTLA-4 inhibitor combined with chemotherapy compared with chemotherapy alone. 4 Paz-Ares L Ciuleanu T-E Cobo M et al. First-line nivolumab plus ipilimumab combined with two cycles of chemotherapy in patients with non-small-cell lung cancer (CheckMate 9LA): an international, randomised, open-label, phase 3 trial. Lancet Oncol. 2021; 22: 198-211 Google Scholar Durvalumab plus tremelimumab alone or in combination with low-dose or hypofractionated radiotherapy in metastatic non-small-cell lung cancer refractory to previous PD(L)-1 therapy: an open-label, multicentre, randomised, phase 2 trialRadiotherapy did not increase responses to combined PD-L1 plus CTLA-4 inhibition in patients with NSCLC resistant to PD(L)-1 therapy. However, PD-L1 plus CTLA-4 therapy could be a treatment option for some patients. Future studies should refine predictive biomarkers in this setting. Full-Text PDF

A CD8+ T Cell-Related Genes Expression Signature Predicts Prognosis and the Efficacy of Immunotherapy in Breast Cancer.

Immunotherapy has been applied to patients with breast cancer. However, only part of patients benefits from the current immunotherapy. Accurate prediction of individual response to immunotherapy can be beneficial for breast cancer management. CD8+ T cells are the main force of anti-tumor immunity. This study aimed to establish a CD8+ T cell-related gene expression signature for prediction of breast cancer prognostic and immunotherapy efficacy. RNA-seq transcriptomic data was the basics of this research. Weighted gene co-expression network analysis (WGCNA) and the least absolute shrinkage and selection operator (LASSO) Cox regression analysis established the prognostic signature. We identified 290 CD8+ T cell-related genes in the training set and established a risk-score model based on 8-genes panel (SOCS1, IL10, CAMK4, CXCL13, KIR2DS4, TESPA1, CD70 and ICAM4). Subsequently, univariate Cox regression analysis suggested that high risk-score was a risk factor for breast cancer (HR = 3.1, 95%CI 2.0-4.8, P < 0.001). In tumor microenvironment, high-risk tumors present decreased tumor infiltrating CD8+ T cells and increased M2 macrophages. The low-risk patients may benefit more from immune checkpoint blockade immunotherapy than the high-risk patients. Moreover, breast tumors which sensitive to immune checkpoint inhibitor (ICI) showed higher IL10 expression.

The Crosstalk Between Malignant Cells and Tumor-Promoting Immune Cells Relevant to Immunotherapy in Pancreatic Ductal Adenocarcinoma.

Background: Pancreatic ductal adenocarcinoma (PDAC) is dominated by an immunosuppressive microenvironment, which makes immune checkpoint blockade (ICB) often non-responsive. Understanding the mechanisms by which PDAC forms an immunosuppressive microenvironment is important for the development of new effective immunotherapy strategies. Methods: This study comprehensively evaluated the cell-cell communications between malignant cells and immune cells by integrative analyses of single-cell RNA sequencing data and bulk RNA sequencing data of PDAC. A Malignant-Immune cell crosstalk (MIT) score was constructed to predict survival and therapy response in PDAC patients. Immunological characteristics, enriched pathways, and mutations were evaluated in high- and low MIT groups. Results: We found that PDAC had high level of immune cell infiltrations, mainly were tumor-promoting immune cells. Frequent communication between malignant cells and tumor-promoting immune cells were observed. 15 ligand-receptor pairs between malignant cells and tumor-promoting immune cells were identified. We selected genes highly expressed on malignant cells to construct a Malignant-Immune Crosstalk (MIT) score. MIT score was positively correlated with tumor-promoting immune infiltrations. PDAC patients with high MIT score usually had a worse response to immune checkpoint blockade (ICB) immunotherapy. Conclusion: The ligand-receptor pairs identified in this study may provide potential targets for the development of new immunotherapy strategy. MIT score was established to measure tumor-promoting immunocyte infiltration. It can serve as a prognostic indicator for long-term survival of PDAC, and a predictor to ICB immunotherapy response.

NKG7 Is Required for Optimal Antitumor T-cell Immunity.

Tumor antigen-specific CD8+ T cells play a critical role in antitumor immunity. Clinical trials reinvigorating the immune system via immune checkpoint blockade (ICB) have shown remarkable clinical promise. Numerous studies have identified an association between NKG7 expression and patient outcome across different malignancies. However, aside from these correlative observations, very little is known about NKG7 and its role in antitumor immunity. Herein, we utilized single-cell RNA sequencing (scRNA-seq) datasets, NKG7-deficient mice, NKG7-reporter mice, and mouse tumor models to investigate the role of NKG7 in neoantigen-mediated tumor rejection and ICB immunotherapy. scRNA-seq of tumors from patients with metastatic melanoma or head and neck squamous cell carcinoma revealed that NKG7 expression is highly associated with cytotoxicity and specifically expressed by CD8+ T cells and natural killer (NK) cells. Furthermore, we identified a key role for NKG7 in controlling intratumor T-cell accumulation and activation. NKG7 was upregulated on intratumor antigen-specific CD8+ T cells and NK cells and required for the accumulation of T cells in the tumor microenvironment. Accordingly, neoantigen-expressing mouse tumors grew faster in Nkg7-deficient mice. Strikingly, efficacy of single or combination ICB was significantly reduced in Nkg7-deficient mice.See related article by Wen et al., p. 162.

A pan-cancer immunogenomic atlas for immune checkpoint blockade immunotherapy.

The ability to identify robust genomic signatures that predict response to immune checkpoint blockade is restricted by limited sample sizes and ungeneralizable performance across cohorts. To address these challenges, we established Cancer-Immu (http://bioinfo.vanderbilt.edu/database/Cancer-Immu/) a comprehensive platform that integrates large-scale multidimensional omics data, including genetic, bulk, and single-cell transcriptomic, proteomic, and dynamic genomic profiles, with clinical phenotypes to explore consistent and rare immunogenomic connections. Currently Cancer-Immu has incorporated data for 3,652 samples for 16 cancer types. It provides easy access to immunogenomic data and empowers researchers to translate omics datasets into biological insights and clinical applications.

Inhibition of tumor-associated macrophages by trabectedin improves the antitumor adaptive immunity in response to anti-PD-1 therapy.

A considerable proportion of cancer patients are resistant or only partially responsive to immune checkpoint blockade immunotherapy. Tumor‐Associated Macrophages (TAMs) infiltrating the tumor stroma suppress the adaptive immune responses and, hence, promote tumor immune evasion. Depletion of TAMs or modulation of their protumoral functions is actively pursued, with the purpose of relieving this state of immunesuppression. We previously reported that trabectedin, a registered antitumor compound, selectively reduces monocytes and TAMs in treated tumors. However, its putative effects on the adaptive immunity are still unclear. In this study, we investigated whether treatment of tumor‐bearing mice with trabectedin modulates the presence and functional activity of T‐lymphocytes.In treated tumors, there was a significant upregulation of T cell‐associated genes, including CD3, CD8, perforin, granzyme B, and IFN‐responsive genes (MX1, CXCL10, and PD‐1), indicating that T lymphocytes were activated after treatment. Notably, the mRNA levels of the Pdcd1 gene, coding for PD‐1, were strongly increased. Using a fibrosarcoma model poorly responsive to PD‐1‐immunotherapy, treatment with trabectedin prior to anti‐PD‐1 resulted in improved antitumor efficacy. In conclusion, pretreatment with trabectedin enhances the therapeutic response to checkpoint inhibitor‐based immunotherapy. These findings provide a good rational for the combination of trabectedin with immunotherapy regimens.

B7-H5 blockade enhances CD8+ T-cell-mediated antitumor immunity in colorectal cancer

Negative immune checkpoint blockade immunotherapy has shown potential for multiple malignancies including colorectal cancer (CRC). B7-H5, a novel negative immune checkpoint regulator, is highly expressed in tumor tissues and promotes tumor immune escape. However, the clinical significance of B7-H5 expression in CRC and the role of B7-H5 in the tumor microenvironment (TME) has not been fully clarified. In this study, we observed that high B7-H5 expression in CRC tissues was significantly correlated with the lymph node involvement, AJCC stage, and survival of CRC patients. A significant inverse correlation was also observed between B7-H5 expression and CD8+ T-cell infiltration in CRC tissues. Kaplan−Meier analysis showed that patients with high B7-H5 expression and low CD8+ T-cell infiltration had the worst prognosis in our cohort of CRC patients. Remarkably, both high B7-H5 expression and low CD8+ T infiltration were risk factors for overall survival. Additionally, B7-H5 blockade using a B7-H5 monoclonal antibody (B7-H5 mAb) effectively suppressed the growth of MC38 colon cancer tumors by enhancing the infiltration and Granzyme B production of CD8+ T cells. Importantly, the depletion of CD8+ T cells obviously abolished the antitumor effect of B7-H5 blockade in the MC38 tumors. In sum, our findings suggest that B7-H5 may be a valuably prognostic marker for CRC and a potential target for CRC immunotherapy.

Renal Clearable Ultrasmall Single-Crystal Fe Nanoparticles for Highly Selective and Effective Ferroptosis Therapy and Immunotherapy.

Iron-based nanoparticles have attracted much attention because of their ability to induce ferroptosis via a catalyzing Fenton reaction and to further potentiate immunotherapy. However, current iron-based nanoparticles need to be used in cooperation with other treatments or be applied in a high dose for effective therapy because of their low reactive oxygen species production efficacy. Here, we synthesized ultrasmall single-crystal Fe nanoparticles (bcc-USINPs) that stayed stable in a normal physiological environment but were highly active in a tumor microenvironment because of the selective acidic etching of an Fe3O4 shell and the exposure of the Fe(0) core. The bcc-USINPs could efficiently induce tumor cell ferroptosis and immunogenetic cell death at a very low concentration. Intravenous injection of iRGD-bcc-USINPs at three doses of 1 mg/kg could effectively suppress the tumor growth, promote the maturation of dendritic cells, and trigger the adaptive T cell response. Combined with programmed death-ligand 1 (PD-L1) immune checkpoint blockade immunotherapy, the iRGD-bcc-USINP-mediated ferroptosis therapy greatly potentiated the immune response and developed strong immune memory. In addition, these USINPs were quickly renal excreted with no side effects in normal tissues. These iRGD-bcc-USINPs provide a simple, safe, effective, and selectively tumor-responsive Fe(0) delivery system for ferroptosis-based immunotherapy.

Multifunctional carbon monoxide nanogenerator as immunogenic cell death drugs with enhanced antitumor immunity and antimetastatic effect

The limited effect of immune checkpoint blockade (ICB) immunotherapy is subjected to the immuno-suppressive tumor microenvironment (TME). It is still a challenge to reverse the immune-suppressive state in clinical cancer therapy. Immunogenic cell death (ICD) is a way for inducing the therapeutical tumor immune system. In this work, carbon monoxide (CO) gas therapy is used to boost antitumor immunity for tumor control, metastasis and recurrence prevention. Briefly, CO2-g–C3N4–Au@ZIF-8@F127 (CCAZF) is proposed to integrate gas therapy and immunotherapy into a photocatalytic nanogenerator for overcoming the limitations of monotherapy. CCAZF exhibits a highly effective light-controllable release behavior of CO, which gradually aggravates the oxidative stress in tumor cells to induce ICD. With the induction of ICD, CO therapy enhances immune responses and enables efficient immune cells activated. When combined with ICB, CCAZF displays an enhanced immune effect, which mediates the regression of primary and distal tumors. This strategy of in-situ photocatalytic CO therapy furthest avoids the toxicity from CO leakage and provides a new method to design novel ICD inducers.

Multi-omics analysis reveals prognostic value of tumor mutation burden in hepatocellular carcinoma

BackgroundHepatocellular carcinoma (HCC) was the sixth common malignancies characteristic with highly aggressive in the world. It was well established that tumor mutation burden (TMB) act as indicator of immunotherapeutic responsiveness in various tumors. However, the role of TMB in tumor immune microenvironment (TIME) is still obscure.MethodThe mutation data was analyzed by employing “maftools” package. Weighted gene co-expression network analysis (WGCNA) was implemented to determine candidate module and significant genes correlated with TMB value. Differential analysis was performed between different level of TMB subgroups employing R package “limma”. Gene ontology (GO) enrichment analysis was implemented with “clusterProfiler”, “enrichplot” and “ggplot2” packages. Then risk score signature was developed by systematical bioinformatics analyses. K-M survival curves and receiver operating characteristic (ROC) plot were further analyzed for prognostic validity. To depict comprehensive context of TIME, XCELL, TIMER, QUANTISEQ, MCPcounter, EPIC, CIBERSORT, and CIBERSORT-ABS algorithm were employed. Additionally, the potential role of risk score on immune checkpoint blockade (ICB) immunotherapy was further explored. The quantitative real-time polymerase chain reaction was performed to detect expression of HTRA3.ResultsTMB value was positively correlated with older age, male gender and early T status. A total of 75 intersection genes between TMB-related genes and differentially expressed genes (DEGs) were screened and enriched in extracellular matrix-relevant pathways. Risk score based on three hub genes significantly affected overall survival (OS) time, infiltration of immune cells, and ICB-related hub targets. The prognostic performance of risks score was validated in the external testing group. Risk-clinical nomogram was constructed for clinical application. HTRA3 was demonstrated to be a prognostic factor in HCC in further exploration. Finally, mutation of TP53 was correlated with risk score and do not interfere with risk score-based prognostic prediction.ConclusionCollectively, a comprehensive analysis of TMB might provide novel insights into mutation-driven mechanism of tumorigenesis further contribute to tailored immunotherapy and prognosis prediction of HCC.

Analysis of immune checkpoint blockade biomarkers in elderly patients using large-scale cancer genomics data.

2543 Background: Immune checkpoint blockade (ICB) immunotherapy in some cases elicits striking patient responses, but its efficacy appears to be dependent on several incompletely understood factors. Most studies of ICB therapies in elderly patients have concluded that they received no reduced benefit or even increased benefit compared to the younger patients analyzed, despite the systemic age-related immune changes that might be expected to produce a less effective immune response, such as loss of the capacity to generate new naive T cells. To understand and apply these results, it is necessary to investigate the relationship of age and the immune tumor microenvironment. Methods: We apply bioinformatics methods to genomic, transcriptomic, and clinical data from 9,523 patients across 31 cancer types from TCGA, 15,557 patients with breast, colon, or head and neck cancers from Caris Life Sciences, and 37,961 patients across 8 cancer types collected by GENIE. From these data we apply multivariate linear models across and within individual tumor types to estimate age-related associations to tumor mutational burden (TMB), T cell receptor diversity (miTCR), differential gene expression (edgeR), pathway enrichment (mSigDB and fgsea), and immune cell type infiltration (Quantiseq and MIXTURE). Results: Our analysis of large-scale molecular and clinical databases associates patient age with changes in several major biomarkers of ICB response. Notably, a robust correlation between increased tumor mutational burden and age was found across three different large cohorts (TCGA, Caris Life Sciences, and GENIE) in most ICB-approved cancer types. In the TCGA data, TMB increased with age pan-cancer (p &lt; 1x10-16) and in 7 of 9 ICB-approved cancer types. These associations were validated in the larger cohort of patient samples in GENIE, which demonstrated correlations between increased TMB levels and patient age in all eight ICB-approved cancer types assayed (Table), as well as in the Caris colorectal (q &lt; 0.001) and breast (q &lt; 0.001) cancer cohorts. Significant associations of age to other biomarkers of ICB response (checkpoint gene expression, immune infiltration, and immune related pathway signaling) will be presented. Conclusions: These results provide context for the efficacy of ICB in elderly patients, highlight potential biomarkers for the treatment of elderly patients with immunotherapies, and strongly suggest the value of large-scale prospective study of elderly cancer patients treated with ICB.[Table: see text]

Modulation of CD8+ T cell antitumor function by an immune inhibitory molecule sushi domain containing 2

Abstract A central mechanism by which the immunosuppressive tumor microenvironment (TME) facilitates tumor growth is the inhibition of CD8+ effector T cell function. Indeed, restoration of CD8+ T cell antitumor functions by immune checkpoint blockade (ICB) treatment represents a significant breakthrough in cancer therapy. However, a major challenge remaining in ICB immunotherapy is the existence of multiple immune checkpoint molecules. As a result, targeting of a single molecule cannot override compensatory signals from other immune inhibitory molecules. Therefore, there is an urgent need to identify new therapeutic target(s) to rejuvenate CD8+ T cell antitumor immunity for cancer therapy. Through unbiased gene profiling assay, our recent study has identified SUSD2 (sushi domain containing 2) as a highly expressed immune cell-associated cell surface molecule in an experimental cancer model. Using a newly developed Susd2 gene-deletion (Susd2−/−) mouse model, we found that genetic deletion of Susd2 led to an improved control of tumor growth in syngeneic tumor models including colorectal carcinoma MC38 and thymoma EG7. This improved tumor control phenotype of Susd2−/− mice required the presence of CD8+ T cells. Single-cell RNA sequencing assay revealed increased production of effector molecules such as granzyme B (Gzmb) and interferon (IFN)-γ in tumor-infiltrating CD8+ T cells from Susd2−/− mice compared to those from wild-type (WT) mice. Mechanistically, we found that SUSD2 negatively regulated IL-2 receptor (IL-2R)-mediated generation of Gzmb and IFN-g in CD8+ T cells. In sum, our results identify SUSD2 as a new immune inhibitory molecule which can be targeted to augment CD8+ T cell antitumor response.

Tumor-resident memory CD8+ T cells have a pivotal role in cancer immunity and immunotherapy.

Abstract CD8+ resident memory T (TRM) cells expressing the CD103 integrin frequently accumulate in human lung tumors and are associated with a favorable prognosis. However, the contribution of this T-cell subset to anti-tumor immunity and to the response to immune checkpoint blockade (ICB) immunotherapy has not been established. Using quantitative multiplex immunofluorescence staining on a cohort of non-small-cell lung cancer (NSCLC) patients treated with PD-1-targeted immunotherapy, we show that an increased density of CD103+CD8+ cells in tumors is associated with greatly improved outcome. CD103+CD8+ cells co-expressed CD49a and CD69, and display a molecular profile characterized by expression of PD-1 and CD39 exhaustion markers, and T-bet, AhR and phosphorylated-STAT-3 transcriptions factors, which confer them a Tc1/Tc17 profile. Moreover, CD103+CD8+ tumor TRM cells, but not CD103−CD8+ (non-TRM) tumor-infiltrating counterparts, demonstrate enhanced proliferation and cytotoxicity toward autologous cancer cells, and display oligoclonal expansion of specific TCRβ clonotypes. Human lung tumors are also infiltrated by CD103+CD4+ T cells likely suggesting a role for this resident population in orchestrating the antitumor T-cell response. Moreover, data obtained in pre-clinical mouse tumor models demonstrate that the absence of CD103 on CD8+ T cells impact the antitumor immune responses. These results explain why CD103+CD8+ tumor-reactive TRM cells are associated with better outcome in ICB-treated patients.

Prospects of immune checkpoint blockade and vaccine-based immunotherapy for glioblastoma

AbstractGlioblastoma multiforme (GBM) is the most prevalent primary brain tumor endowed with a dismal prognosis. Nowadays, immunotherapy in a particular immune checkpoint blockade and therapeutic vaccines are being extensively pursued. Yet, several characteristics of GBM may impact such immunotherapeutic approaches. This includes tumor heterogeneity, the relatively low mutational load of primary GBM, insufficient delivery of antibodies to tumor parenchyma and the unique immunosuppressive microenvironment of GBM. Moreover, standard treatment of GBM, comprising temozolomide chemotherapy, radiotherapy and in most instances the application of glucocorticoids for management of brain edema, results in a further increased immunosuppression. This review will provide a brief introduction to the principles of vaccine-based immunotherapy and give an overview of the current clinical studies, which employed immune checkpoint inhibitors, oncolytic viruses-based vaccination, cell-based and peptide-based vaccines. Recent experiences as well as the latest developments are reviewed. Overcoming obstacles, which limit the induction and long-term immune response against GBM when using vaccination approaches, are necessary for the implementation of effective immunotherapy of GBM.

Understanding the Immune-Stroma Microenvironment in B Cell Malignancies for Effective Immunotherapy.

Cancers, including lymphomas, develop in complex tissue environments where malignant cells actively promote the creation of a pro-tumoral niche that suppresses effective anti-tumor effector T cell responses. Research is revealing that the tumor microenvironment (TME) differs between different types of lymphoma, covering inflamed environments, as exemplified by Hodgkin lymphoma, to non-inflamed TMEs as seen in chronic lymphocytic leukemia (CLL) or diffuse-large B-cell lymphoma (DLBCL). In this review we consider how T cells and interferon-driven inflammatory signaling contribute to the regulation of anti-tumor immune responses, as well as sensitivity to anti-PD-1 immune checkpoint blockade immunotherapy. We discuss tumor intrinsic and extrinsic mechanisms critical to anti-tumor immune responses, as well as sensitivity to immunotherapies, before adding an additional layer of complexity within the TME: the immunoregulatory role of non-hematopoietic stromal cells that co-evolve with tumors. Studying the intricate interactions between the immune-stroma lymphoma TME should help to design next-generation immunotherapies and combination treatment strategies to overcome complex TME-driven immune suppression.

Titin mutation in circulatory tumor DNA is associated with efficacy to immune checkpoint blockade in advanced non-small cell lung cancer.

BackgroundOnly a fraction of patients with advanced non-small cell lung cancer (NSCLC) respond well to immune checkpoint blockade (ICB) therapy. Here, we investigated whether Titin (TTN) mutation, which has been demonstrated to be a predictive biomarker in tissue-based analysis, can identify patients with a greater likelihood in response to ICB based on circulatory tumor DNA (ctDNA) sequencing.MethodsIn this retrospective analysis, 92 patients with advanced NSCLC from two independent cohorts who received ICB treatment were included. A probe panel covering all exons of TTN was developed and validated to detect TTN mutation in ctDNA. Baseline plasma samples were collected and subjected to ctDNA sequencing with the TTN probe panel.ResultsOf the 92 patients, 28.3% harbored TTN mutation in their baseline ctDNA. Progression-free survival was significantly improved in patients with the mutated TTN (212 days and 334.5 days for cohort 1 and 2) compared to those without the mutation (113 days and 147 days for cohort 1 and 2). Objective response to ICB treatment (40% for TTNmut and 15.8% for TTNwt in cohort 1; 50% for TTNmut and 23.4% for TTNwt in cohort 2) was common in patients with mutated TTN. Stratified analysis showed a generally predictive potential of TTN mutation in patients with advanced NSCLC.ConclusionsThe presence of mutated TTN in pre-treatment peripheral blood was associated with favorable objective response and survival with ICB administration. Therefore, circulatory TTN mutation may be applicable for guiding ICB immunotherapy in patients with NSCLC.

Enhancing the Efficacy of Tumor Vaccines Based on Immune Evasion Mechanisms.

Tumor vaccines aim to expand tumor-specific T cells and reactivate existing tumor-specific T cells that are in a dormant or unresponsive state. As such, there is growing interest in improving the durable anti-tumor activity of tumor vaccines. Failure of vaccine-activated T cells to protect against tumors is thought to be the result of the immune escape mechanisms of tumor cells and the intricate immunosuppressive tumor microenvironment. In this review, we discuss how tumor cells and the tumor microenvironment influence the effects of tumor infiltrating lymphocytes and summarize how to improve the efficacy of tumor vaccines by improving the design of current tumor vaccines and combining tumor vaccines with other therapies, such as metabolic therapy, immune checkpoint blockade immunotherapy and epigenetic therapy.

The Potential Regulatory Roles of Circular RNAs in Tumor Immunology and Immunotherapy.

Circular RNAs (circRNAs) are covalently closed RNA molecules in eukaryotes with features of high stability, tissue-specific and cell-specific expression. According to their biogenesis, circRNAs are mainly classified into five types, i.e. exonic circRNAs (EciRNAs), exon-intron circRNAs (EIciRNAs), intronic RNAs (CiRNAs), fusion circRNAs (f-circRNAs), and read-through circRNAs (rt-circRNAs). CircRNAs have been emerging as important non-coding regulatory RNAs in a variety of human cancers. CircRNA4s were revealed to exert regulatory function through multiple mechanisms, such as sponges/decoys of miRNAs and proteins, enhancers of protein functions, protein scaffolds, protein recruitment, or protein translation templates. Furthermore, some circRNAs are intensively associated with immune cells in tumor immune microenvironment (TIME), e.g. circARSP91 and natural killer cells. Through regulating immune checkpoint genes, circRNAs are demonstrated to modulate the immune checkpoint blockade immunotherapy, e.g. circCPA4 could up-regulate PD-L1 expression. In summary, we reviewed the molecular features of circRNAs and mechanisms how they exert functions. We further summarized functional implications of circRNA regulations in tumor immunology and immunotherapy. Further understanding of the regulatory roles of circRNAs in tumor immunology and immunotherapy will benefit tumor treatment.

Arginase Therapy Combines Effectively with Immune Checkpoint Blockade or Agonist Anti-OX40 Immunotherapy to Control Tumor Growth

Metabolic dysregulation is a hallmark of cancer. Many tumors exhibit auxotrophy for various amino acids, such as arginine, because they are unable to meet the demand for these amino acids through endogenous production. This vulnerability can be exploited by employing therapeutic strategies that deplete systemic arginine in order to limit the growth and survival of arginine auxotrophic tumors. Pegzilarginase, a human arginase-1 enzyme engineered to have superior stability and enzymatic activity relative to the native human arginase-1 enzyme, depletes systemic arginine by converting it to ornithine and urea. Therapeutic administration of pegzilarginase in the setting of arginine auxotrophic tumors exerts direct antitumor activity by starving the tumor of exogenous arginine. We hypothesized that in addition to this direct effect, pegzilarginase treatment indirectly augments antitumor immunity through increased antigen presentation, thus making pegzilarginase a prime candidate for combination therapy with immuno-oncology (I-O) agents. Tumor-bearing mice (CT26, MC38, and MCA-205) receiving pegzilarginase in combination with anti-PD-L1 or agonist anti-OX40 experienced significantly increased survival relative to animals receiving I-O monotherapy. Combination pegzilarginase/immunotherapy induced robust antitumor immunity characterized by increased intratumoral effector CD8+ T cells and M1 polarization of tumor-associated macrophages. Our data suggest potential mechanisms of synergy between pegzilarginase and I-O agents that include increased intratumoral MHC expression on both antigen-presenting cells and tumor cells, and increased presence of M1-like antitumor macrophages. These data support the clinical evaluation of I-O agents in conjunction with pegzilarginase for the treatment of patients with cancer.

Identification of immune-related lncRNA signature for predicting immune checkpoint blockade and prognosis in hepatocellular carcinoma

BackgroundAn increasing body of evidence has supported that long non-coding RNAs (lncRNAs) can play as essential roles of various physiological process and pathological diseases. We aimed to construct a robust immune-associated lncRNA signature associated with the prognosis for HCC survival prediction. Methods7 immune‐associated lncRNAs presenting significant correlation with survival were screened through stepwise univariate Cox regression and LASSO algorithm, and multivariate Cox regression. Kaplan-Meier analysis, proportional hazards model, and ROC analyses further conducted. Gene set enrichment analysis (GSEA) was applied for functional annotation. We conducted quantitative real-time polymerase chain reaction to determine NRAV expression and preliminarily explored the latent role of NRAV in prognosis of HCC patients. ResultsFinally, 7 immune-related lncRNA signature composed of AC007405.3, AC023157.3, NRAV, CASC19, MSC–AS1, GASAL1, and LINC00942 were validated. This lncRNAs signature can serve as an independent predictive biomolecular factor. This signature was further confirmed in the validation group and the entire cohort. We demonstrated that NRAV was significantly upregulated in HCC cell lines and it may serve as a key regulator in HCC. Our signature was associated to apoptosis and immunologic characteristics. This signature mediated immune cell infiltration (i.e., Dendritic, etc.,) and immune checkpoint blockade (ICB) immunotherapy‐related molecules (i.e., CD274, etc.,). ConclusionThis immune‐related lncRNA signature possesses promising prognostic value in HCC and may have the potentiality to predict clinical outcome of ICB immunotherapy.