The Next Hurdle in Cancer Immunotherapy: Overcoming the Non-T-Cell-Inflamed Tumor Microenvironment

Inflammation and tumor progression: signaling pathways and targeted intervention

Cancer development and its response to therapy are regulated by inflammation, which either promotes or suppresses tumor progression, potentially displaying opposing effects on therapeutic outcomes. Chronic inflammation facilitates tumor progression and treatment resistance, whereas induction of acute inflammatory reactions often stimulates the maturation of dendritic cells (DCs) and antigen presentation, leading to anti-tumor immune responses. In addition, multiple signaling pathways, such as nuclear factor kappa B (NF-kB), Janus kinase/signal transducers and activators of transcription (JAK-STAT), toll-like receptor (TLR) pathways, cGAS/STING, and mitogen-activated protein kinase (MAPK); inflammatory factors, including cytokines (e.g., interleukin (IL), interferon (IFN), and tumor necrosis factor (TNF)-α), chemokines (e.g., C-C motif chemokine ligands (CCLs) and C-X-C motif chemokine ligands (CXCLs)), growth factors (e.g., vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β), and inflammasome; as well as inflammatory metabolites including prostaglandins, leukotrienes, thromboxane, and specialized proresolving mediators (SPM), have been identified as pivotal regulators of the initiation and resolution of inflammation. Nowadays, local irradiation, recombinant cytokines, neutralizing antibodies, small-molecule inhibitors, DC vaccines, oncolytic viruses, TLR agonists, and SPM have been developed to specifically modulate inflammation in cancer therapy, with some of these factors already undergoing clinical trials. Herein, we discuss the initiation and resolution of inflammation, the crosstalk between tumor development and inflammatory processes. We also highlight potential targets for harnessing inflammation in the treatment of cancer.

Combination of radiation therapy, bempegaldesleukin, and checkpoint blockade eradicates advanced solid tumors and metastases in mice

Background

Current clinical trials are using radiation therapy (RT) to enhance an antitumor response elicited by high-dose interleukin (IL)-2 therapy or immune checkpoint blockade (ICB). Bempegaldesleukin (BEMPEG) is an investigational CD122-preferential IL-2 pathway agonist with prolonged in vivo half-life and preferential intratumoral expansion of T effector cells over T regulatory cells. BEMPEG has shown encouraging safety and efficacy in clinical trials when used in combination with PD-1 checkpoint blockade. In this study, we investigated the antitumor effect of local RT combined with BEMPEG in multiple immunologically ‘cold’ tumor models. Additionally, we asked if ICB could further enhance the local and distant antitumor effect of RT+BEMPEG in the setting of advanced solid tumors or metastatic disease.

Methods

Mice bearing flank tumors (B78 melanoma, 4T1 breast cancer, or MOC2 head and neck squamous cell carcinoma) were treated with combinations of RT and immunotherapy (including BEMPEG, high-dose IL-2, anti(α)-CTLA-4, and α-PD-L1). Mice bearing B78 flank tumors were injected intravenously with B16 melanoma cells to mimic metastatic disease and were subsequently treated with RT and/or immunotherapy. Tumor growth and survival were monitored. Peripheral T cells and tumor-infiltrating lymphocytes were assessed via flow cytometry.

Results

A cooperative antitumor effect was observed in all models when RT was combined with BEMPEG, and RT increased IL-2 receptor expression on peripheral T cells. This cooperative interaction was associated with increased IL-2 receptor expression on peripheral T cells following RT. In the B78 melanoma model, RT+BEMPEG resulted in complete tumor regression in the majority of mice with a single ~400 mm³ tumor. This antitumor response was T-cell dependent and supported by long-lasting immune memory. Adding ICB to RT+BEMPEG strengthened the antitumor response and cured the majority of mice with a single ~1000 mm³ B78 tumor. In models with disseminated metastasis (B78 primary with B16 metastasis, 4T1, and MOC2), the triple combination of RT, BEMPEG, and ICB significantly improved primary tumor response and survival.

Conclusion

The combination of local RT, BEMPEG, and ICB cured mice with advanced, immunologically cold tumors and distant metastasis in a T cell-dependent manner, suggesting this triple combination warrants clinical testing.

Response Prediction and Evaluation Using PET in Patients with Solid Tumors Treated with Immunotherapy

Simple Summary

In cancer treatment, immunotherapy is increasingly becoming important as a component of first-line treatment and has improved the prognosis of patients since its introduction. A large group of patients, however, do not respond to immunotherapy, and predicting a treatment response remains challenging. Furthermore, evaluating a response using conventional computed tomography (CT) scans is not straightforward due to the different mechanism of action of immunotherapy compared to chemotherapy. This review provides an overview of positron emission tomography (PET) in predicting and evaluating treatment response to immunotherapy.

Abstract

In multiple malignancies, checkpoint inhibitor therapy has an established role in the first-line treatment setting. However, only a subset of patients benefit from checkpoint inhibition, and as a result, the field of biomarker research is active. Molecular imaging with the use of positron emission tomography (PET) is one of the biomarkers that is being studied. PET tracers such as conventional ¹⁸F-FDG but also PD-(L)1 directed tracers are being evaluated for their predictive power. Furthermore, the use of artificial intelligence is under evaluation for the purpose of response prediction. Response evaluation during checkpoint inhibitor therapy can be challenging due to the different response patterns that can be observed compared to traditional chemotherapy. The additional information provided by PET can potentially be of value to evaluate a response early after the start of treatment and provide the clinician with important information about the efficacy of immunotherapy. Furthermore, the use of PET to stratify between patients with a complete response and those with a residual disease can potentially guide clinicians to identify patients for which immunotherapy can be discontinued and patients for whom the treatment needs to be escalated. This review provides an overview of the use of positron emission tomography (PET) to predict and evaluate treatment response to immunotherapy.

STING activation normalizes the intraperitoneal vascular-immune microenvironment and suppresses peritoneal carcinomatosis of colon cancer

Background

Peritoneal carcinomatosis is a fatal clinical presentation of colon cancer, characterized by unresponsiveness to conventional anticancer therapies, including immune checkpoint inhibitors. Here, we elucidated the immune-evasion mechanisms during the peritoneal carcinomatosis of colon cancer and developed a novel immunotherapy by activating the stimulator of interferon genes (STING) pathway.

Methods

We generated a syngeneic peritoneal carcinomatosis model of colon cancer. Mice were intraperitoneally treated with either STING agonist (MIW815, also known as ADU-S100) or PD-1 blockade or both. The tumor microenvironment was comprehensively analyzed using multiplexed immunofluorescence imaging, flow cytometry, and NanoString immune profiling.

Results

Intraperitoneal colon cancer cells induce a massive influx of immunosuppressive M2-like macrophages, upregulate immune checkpoints, and impair effector T cell functions during peritoneal dissemination; these collectively create a highly angiogenic and immunosuppressive milieu that is resistant to anti-PD-1 monotherapy. Intraperitoneal administration of a STING agonist suppressed aberrant angiogenesis, increased pericyte coverage, and normalized tumor vessels, thereby facilitating the infiltration of activated CD8⁺ T cells into peritoneal tumor nodules. Moreover, STING activation reprogramed tumor-associated macrophages toward the M1 phenotype. STING activation converted immunologically cold peritoneal tumors into T-cell-inflamed tumors in a type-I interferon-dependent manner. Lastly, the STING agonist synergistically cooperated with PD-1 and/or COX2 blockade to further suppress the peritoneal dissemination of colon cancer, resulting in complete eradication of tumor and ascites, and inducing durable antitumor immunity.

Conclusions

STING activation can normalize the peritoneal vascular and immune microenvironment, providing a rationale for a novel combination therapeutic strategy for peritoneal carcinomatosis in colon cancer.

A Tumor Progression Related 7-Gene Signature Indicates Prognosis and Tumor Immune Characteristics of Gastric Cancer

BACKGROUND

Gastric cancer is a common gastrointestinal malignancy. Since it is often diagnosed in the advanced stage, its mortality rate is high. Traditional therapies (such as continuous chemotherapy) are not satisfactory for advanced gastric cancer, but immunotherapy has shown great therapeutic potential. Gastric cancer has high molecular and phenotypic heterogeneity. New strategies for accurate prognostic evaluation and patient selection for immunotherapy are urgently needed.

METHODS

Weighted gene coexpression network analysis (WGCNA) was used to identify hub genes related to gastric cancer progression. Based on the hub genes, the samples were divided into two subtypes by consensus clustering analysis. After obtaining the differentially expressed genes between the subtypes, a gastric cancer risk model was constructed through univariate Cox regression, least absolute shrinkage and selection operator (LASSO) regression and multivariate Cox regression analysis. The differences in prognosis, clinical features, tumor microenvironment (TME) components and immune characteristics were compared between subtypes and risk groups, and the connectivity map (CMap) database was applied to identify potential treatments for high-risk patients.

RESULTS

WGCNA and screening revealed nine hub genes closely related to gastric cancer progression. Unsupervised clustering according to hub gene expression grouped gastric cancer patients into two subtypes related to disease progression, and these patients showed significant differences in prognoses, TME immune and stromal scores, and suppressive immune checkpoint expression. Based on the different expression patterns between the subtypes, we constructed a gastric cancer risk model and divided patients into a high-risk group and a low-risk group based on the risk score. High-risk patients had a poorer prognosis, higher TME immune/stromal scores, higher inhibitory immune checkpoint expression, and more immune characteristics suitable for immunotherapy. Multivariate Cox regression analysis including the age, stage and risk score indicated that the risk score can be used as an independent prognostic factor for gastric cancer. On the basis of the risk score, we constructed a nomogram that relatively accurately predicts gastric cancer patient prognoses and screened potential drugs for high-risk patients.

CONCLUSIONS

Our results suggest that the 7-gene signature related to tumor progression could predict the clinical prognosis and tumor immune characteristics of gastric cancer.

Cancer-associated fibroblasts: Key players in shaping the tumor immune microenvironment

Cancer immunotherapies have rapidly changed the therapeutic landscape for cancer. Nevertheless, most of the patients show innate or acquired resistance to these therapies. Studies conducted in recent years have highlighted an emerging role of cancer-associated fibroblasts (CAFs) in immune regulation that shapes the tumor immune microenvironment (TIME) and influences response to cancer immunotherapies. In this review, we outline recent advances in the understanding of phenotypic and functional heterogeneity of CAFs. We will focus on emerging roles of CAFs in shaping the TIME, especially under a framework of tumor immunity continuum, and discuss current and future CAF-targeting therapeutic strategies in particular in the context of optimizing the success of immunotherapies.

Synergistic Activation of Antitumor Immunity by a Particulate Therapeutic Vaccine

Success in anticancer immune therapy relies on stimulation of tumor antigen-specific T lymphocytes and effective infiltration of the T cells into tumor tissue. Here, a therapeutic vaccine that promotes proliferation and tumor infiltration of antigen-specific T cells in both inflamed and noninflamed tumor types is described. The vaccine consists of STING agonist 2'3'-cGAMP, TLR9 ligand CpG, and tumor antigen peptides that are loaded into nanoporous microparticles (μGCVax). μGCVax is effective in inhibiting lung metastatic melanoma, primary breast cancer, and subcutaneous colorectal cancer in their respective murine models, including functional cure of HER2-positive breast cancer. Mechanistically, μGCVax potently stimulates type I interferon expression in dendritic cells, and promotes CD8+ and CD103+ dendritic cell maturation and migration to lymph nodes and other lymphatic tissues. Antitumor responses are dependent on TLR9 and interferon α/β receptor signaling, and to a less extent on STING signaling. These results demonstrate a high potential for μGCVax in mediating antitumor immunity in personalized cancer therapy.

Immunological Effects of Histotripsy for Cancer Therapy

Cancer is the second leading cause of death worldwide despite major advancements in diagnosis and therapy over the past century. One of the most debilitating aspects of cancer is the burden brought on by metastatic disease. Therefore, an ideal treatment protocol would address not only debulking larger primary tumors but also circulating tumor cells and distant metastases. To address this need, the use of immune modulating therapies has become a pillar in the oncology armamentarium. A therapeutic option that has recently emerged is the use of focal ablation therapies that can destroy a tumor through various physical or mechanical mechanisms and release a cellular lysate with the potential to stimulate an immune response. Histotripsy is a non-invasive, non-ionizing, non-thermal, ultrasound guided ablation technology that has shown promise over the past decade as a debulking therapy. As histotripsy therapies have developed, the full picture of the accompanying immune response has revealed a wide range of immunogenic mechanisms that include DAMP and anti-tumor mediator release, changes in local cellular immune populations, development of a systemic immune response, and therapeutic synergism with the inclusion of checkpoint inhibitor therapies. These studies also suggest that there is an immune effect from histotripsy therapies across multiple murine tumor types that may be reproducible. Overall, the effects of histotripsy on tumors show a positive effect on immunomodulation.

Tumor Immune Microenvironment Characterization Identifies Prognosis and Immunotherapy-Related Gene Signatures in Melanoma

Background

The tumor microenvironment (TME) involves infiltration of multiple immune cell subsets, which could influence the prognosis and clinical characteristics. The increasing evidence on the role of tumor-infiltrating lymphocytes (TILs) in primary and metastatic melanomas supports that the immune system is involved in the progression and outcomes of melanoma. However, the immune infiltration landscape in melanoma has not been systematically elucidated.

Methods

In this study, we used CIBERSORT and ESTIMATE algorithms to analyze immune infiltration pattern of 993 melanoma samples. Then we screened differential expression genes (DEGs) related to immune subtypes and survival. The immune cell infiltration (ICI) score was constructed by using principal-component analysis (PCA) based on immune signature genes from DGEs. Gene set enrichment analysis (GSEA) was applied to explore high and low ICI score related pathways. Finally, the predictive ability of ICI score was evaluated in survival prognosis and immunotherapy benefit.

Result

We identified three ICI clusters and three gene clusters associated with different immune subtypes and survival outcomes. Then the ICI score was constructed, and we found that high ICI score exhibited activated immune characteristics and better prognosis. High ICI score was significantly enriched in immune pathways and highly expressed immune signature genes. More importantly, we confirmed that melanoma patients with high ICI score had longer overall survival and rate of response to immunotherapy.

Conclusion

We presented a comprehensive immune infiltration landscape in melanoma. Our results will facilitate understanding of the melanoma tumor microenvironment and provide a new immune therapy strategy.

Intratumoral expression of interleukin 23 variants using oncolytic vaccinia virus elicit potent antitumor effects on multiple tumor models via tumor microenvironment modulation

Background: Newly emerging cancer immunotherapy has led to significant progress in cancer treatment; however, its efficacy is limited in solid tumors since the majority of them are “cold” tumors. Oncolytic viruses, especially when properly armed, can directly target tumor cells and indirectly modulate the tumor microenvironment (TME), resulting in “hot” tumors. These viruses can be applied as a cancer immunotherapy approach either alone or in combination with other cancer immunotherapies. Cytokines are good candidates to arm oncolytic viruses. IL-23, an IL-12 cytokine family member, plays many roles in cancer immunity. Here, we used oncolytic vaccinia viruses to deliver IL-23 variants into the tumor bed and explored their activity in cancer treatment on multiple tumor models.

Methods: Oncolytic vaccinia viruses expressing IL-23 variants were generated by homologue recombination. The characteristics of these viruses were in vitro evaluated by RT-qPCR, ELISA, flow cytometry and cytotoxicity assay. The antitumor effects of these viruses were evaluated on multiple tumor models in vivo and the mechanisms were investigated by RT-qPCR and flow cytometry.

Results: IL-23 prolonged viral persistence, probably mediated by up-regulated IL-10. The sustainable IL-23 expression and viral oncolysis elevated the expression of Th1 chemokines and antitumor factors such as IFN-γ, TNF-α, Perforin, IL-2, Granzyme B and activated T cells in the TME, transforming the TME to be more conducive to antitumor immunity. This leads to a systemic antitumor effect which is dependent on CD8⁺ and CD4⁺ T cells and IFN-γ. Oncolytic vaccinia viruses could not deliver stable IL-23A to the tumor, attributed to the elevated tristetraprolin which can destabilize the IL-23A mRNA after the viral treatment; whereas vaccinia viruses could deliver membrane-bound IL-23 to elicit a potent antitumor effect which might avoid the possible toxicity normally associated with systemic cytokine exposure.

Conclusion: Either secreted or membrane-bound IL-23-armed vaccinia virus can induce potent antitumor effects and IL-23 is a candidate cytokine to arm oncolytic viruses for cancer immunotherapy.

Novel TGFβ Inhibitors Ameliorate Oral Squamous Cell Carcinoma Progression and Improve the Antitumor Immune Response of Anti-PD-L1 Immunotherapy

TGFβ is a key regulator of oral squamous cell carcinoma (OSCC) progression, and its potential role as a therapeutic target has been investigated with a limited success. This study evaluates two novel TGFβ inhibitors as mono or combinatorial therapy with anti-PD-L1 antibodies (α-PD-L1 Ab) in a murine OSCC model. Immunocompetent C57BL/6 mice bearing malignant oral lesions induced by 4-nitroquinoline 1-oxide (4-NQO) were treated for 4 weeks with TGFβ inhibitors mRER (i.p., 50 μg/d) or mmTGFβ2-7m (10 μg/d delivered by osmotic pumps) alone or in combination with α-PD-L1 Abs (7× i.p. of 100 μg/72 h). Tumor progression and body weight were monitored. Levels of bioactive TGFβ in serum were quantified using a TGFβ bioassay. Tissues were analyzed by immunohistology and flow cytometry. Therapy with mRER or mmTGFβ2-7m reduced tumor burden (P < 0.05) and decreased body weight loss compared with controls. In inhibitor-treated mice, levels of TGFβ in tumor tissue and serum were reduced (P < 0.05), whereas they increased with tumor progression in controls. Both inhibitors enhanced CD8⁺ T-cell infiltration into tumors and mRER reduced levels of myeloid-derived suppressor cells (P < 0.001). In combination with α-PD-L1 Abs, tumor burden was not further reduced; however, mmTGFβ2-7m further reduced weight loss (P < 0.05). The collagen-rich stroma was reduced by using combinatorial TGFβ/PD-L1 therapies (P < 0.05), enabling an accelerated lymphocyte infiltration into tumor tissues. The blockade of TGFβ signaling by mRER or mmTGFβ2-7m ameliorated in vivo progression of established murine OSCC. The inhibitors promoted antitumor immune responses, alone and in combination with α-PD-L1 Abs.

β-Catenin Activation in Hepatocellular Cancer: Implications in Biology and Therapy

Simple Summary

Liver cancer is a dreadful tumor which has gradually increased in incidence all around the world. One major driver of liver cancer is the Wnt–β-catenin pathway which is active in a subset of these tumors. While this pathway is normally important in liver development, regeneration and homeostasis, it’s excessive activation due to mutations, is detrimental and leads to tumor cell growth, making it an important therapeutic target. There are also some unique characteristics of this pathway activation in liver cancer. It makes the tumor addicted to specific amino acids and in turn to mTOR signaling, which can be treated by certain existing therapies. In addition, activation of the Wnt–β-catenin in liver cancer appears to alter the immune cell landscape making it less likely to respond to the new immuno-oncology treatments. Thus, Wnt–β-catenin active tumors may need to be treated differently than non-Wnt–β-catenin active tumors.

Abstract

Hepatocellular cancer (HCC), the most common primary liver tumor, has been gradually growing in incidence globally. The whole-genome and whole-exome sequencing of HCC has led to an improved understanding of the molecular drivers of this tumor type. Activation of the Wnt signaling pathway, mostly due to stabilizing missense mutations in its downstream effector β-catenin (encoded by CTNNB1) or loss-of-function mutations in AXIN1 (the gene which encodes for Axin-1, an essential protein for β-catenin degradation), are seen in a major subset of HCC. Because of the important role of β-catenin in liver pathobiology, its role in HCC has been extensively investigated. In fact, CTNNB1 mutations have been shown to have a trunk role. β-Catenin has been shown to play an important role in regulating tumor cell proliferation and survival and in tumor angiogenesis, due to a host of target genes regulated by the β-catenin transactivation of its transcriptional factor TCF. Proof-of-concept preclinical studies have shown β-catenin to be a highly relevant therapeutic target in CTNNB1-mutated HCCs. More recently, studies have revealed a unique role of β-catenin activation in regulating both tumor metabolism as well as the tumor immune microenvironment. Both these roles have notable implications for the development of novel therapies for HCC. Thus, β-catenin has a pertinent role in driving HCC development and maintenance of this tumor-type, and could be a highly relevant therapeutic target in a subset of HCC cases.

Advances in immunotherapy for pancreatic ductal adenocarcinoma

Advances in immunotherapy against advanced cancers can be considered stunning and epoch-making. Meanwhile, efficacy of immune-based therapies, especially immune checkpoint inhibitors, remains insufficient in pancreatic ductal adenocarcinoma, differing from other immunogenic cancers. To date, neither immunotherapies targeting immune system acceleration nor release of immunologic brakes have been able to overcome the robust immune barrier in the pancreatic tumor microenvironment, which is characterized by rich fibrotic stroma and accumulation of immunosuppressive myeloid cells. However, by receiving an immune checkpoint blockade, patients with abundant tumor-infiltrating lymphocytes in pancreatic ductal adenocarcinoma clearly have better prognosis, and patients with mismatch repair deficiency have achieved better outcomes, albeit in a small population of pancreatic ductal adenocarcinoma. We overview recent preclinical and clinical studies that have been concerned with immune-based therapies including cancer vaccine and immune checkpoint inhibitors. By providing a deep insight into the immunosuppressive tumor microenvironment, we suggest the possibility of comprehensive immune intensification that could reverse the tumor microenvironment, making it conducive to cytotoxic T lymphocyte activity for overcoming pancreatic ductal adenocarcinoma.

Extracellular Vesicles and Their Role in the Spatial and Temporal Expansion of Tumor-Immune Interactions

Extracellular vesicles (EVs) serve as trafficking vehicles and intercellular communication tools. Their cargo molecules directly reflect characteristics of their parental cell. This includes information on cell identity and specific cellular conditions, ranging from normal to pathological states. In cancer, the content of EVs derived from tumor cells is altered and can induce oncogenic reprogramming of target cells. As a result, tumor-derived EVs compromise antitumor immunity and promote cancer progression and spreading. However, this pro-oncogenic phenotype is constantly being challenged by EVs derived from the local tumor microenvironment and from remote sources. Here, we summarize the role of EVs in the tumor–immune cross-talk that includes, but is not limited to, immune cells in the tumor microenvironment. We discuss the potential of remotely released EVs from the microbiome and during physical activity to shape the tumor–immune cross-talk, directly or indirectly, and confer antitumor activity. We further discuss the role of proinflammatory EVs in the temporal development of the tumor–immune interactions and their potential use for cancer diagnostics.

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.

Global Characterization of Immune Infiltration in Clear Cell Renal Cell Carcinoma

Background

Immunotherapy has revolutionized the treatment of clear cell renal cell carcinoma (ccRCC). However, the therapy is constrained by drug resistance. Therefore, further characterization of immune infiltration in ccRCC is needed to improve its efficacy.

Methods

Here, we adopted the CIBERSORT method to analyze the level of 22 immune cells, and analyzed the correlation of immune cells and clinical parameters in ccRCC in The Cancer Genome Atlas. We used consensus clustering to cluster ccRCC and identified differently expressed genes (DEGs) between hot and cold tumors using the "Limma" package, and then performed enrichment analysis of DEGs. Finally, we constructed and validated a Cox regression model using the "survival", "glmnet", and "survivalROC" packages, implemented in R.

Results

Regulatory T cells upregulated in tumor tissue increased during tumor progression, and correlated with poor overall survival in ccRCC. Consensus clustering identified four clusters of ccRCC. To elucidate the underlying mechanisms of immune cell infiltration, we subdivided these four clusters into two major types, immune hot and cold, and identified DEGs between them. The results revealed different transcription profiles in the two tumor types, with hot tumors being enriched in immune-related signaling, whereas cold tumors were enriched in extracellular matrix remodeling and the phosphatidylinositol 3-kinase-AKT (PI3K/AKT) pathway. We further identified hub genes and prognostic-related genes from the DEGs, and constructed a Cox regression model for predicting the overall survival of patients with ccRCC. The areas under the receiver operating characteristics curve for the risk model for the training, testing, and external Zhengzhou validation cohorts were 0.834, 0.733, and 0.812, respectively. Notably, gene sets in the prediction model could also predict the overall survival of patients receiving immunotherapy.

Conclusion

These findings provide a comprehensive characterization of immune infiltration in ccRCC, while the constructed model can be used effectively to predict the overall survival of ccRCC patients.

The Role of Macrophages in Oral Squamous Cell Carcinoma

Oral cancer is a common malignancy worldwide, with high disease-related death rates. Oral squamous cell carcinoma (OSCC) accounts for more than 90% of oral tumors, with surgical management remaining the treatment of choice. However, advanced and metastatic OSCC is still incurable. Thus, emphasis has been given lately in understanding the complex role of the oral tumor microenvironment (TME) in OSCC progression, in order to identify novel prognostic biomarkers and therapeutic targets. Tumor associated macrophages (TAMs) constitute a major population of the OSCC TME, with bipolar role in disease progression depending on their activation status (M1 vs. M2). Here, we provide an up to date review of the current literature on the role of macrophages during oral oncogenesis, as well as their prognostic significance in OSCC survival and response to standard treatment regimens. Finally, we discuss novel concepts regarding the potential use of macrophages as targets for OSCC immunotherapeutics and suggest future directions in the field.

A Novel Immunotype-based Risk Stratification Model Predicts Postoperative Prognosis and Adjuvant TACE Benefit in Chinese Patients with Hepatocellular Carcinoma

Background and Aims: The tumor microenvironment can be divided into inflamed, immune-excluded and immune-desert phenotypes according to CD8⁺ T cell categories with differential programmed cell death protein 1 (PD-L1) expression. The study aims to construct a novel immunotype-based risk stratification model to predict postsurgical survival and adjuvant trans-arterial chemoembolization (TACE) response in patients with hepatocellular carcinoma (HCC).

Methods: A total of 220 eligible HCC patients participated in this study. CD8⁺ T cell infiltration and PD-L1 expression mode were estimated by immunohistochemical staining. A risk stratification model was developed and virtualized by a nomogram that integrated these independent prognostic factors. The postoperative prognosis and adjuvant TACE benefits were evaluated with a novel immunotype-based risk stratification model.

Results: A total of 220 patients were finally identified. Immune-desert, immune-excluded, and inflamed immunotypes represented 45%, 24%, and 31% of HCC, respectively. Univariate and multivariate analyses identified immunotype and PD-L1 expression mode as independent prognostic factors for overall survival time (OS) and recurrence-free survival time (RFS). The nomogram was constructed by integrating immunotype, PD-L1 expression, Barcelona Clinic Liver Cancer (BCLC) stage and tumor grade. The C-index was 0.794 in the training cohort and 0.813 in the validation cohort. A risk stratification system was constructed based on the nomogram classifying HCC patients into 3 risk groups. The average OS times in the low-risk, intermediate-risk and high-risk groups in all cohorts were 77.1 months (95% CI 71.4-82.9), 53.7 months (95% CI 48.2-59.2), and 25.6 months (95% CI 21.4-29.7), respectively. Further analysis showed that OS was significantly improved by adjuvant TACE in the low- and intermediate-risk groups (P=0.041 and P=0.010, respectively) but not in the high-risk group (P=0.398).

Conclusion: A novel immunotype-based risk stratification model was built to predict postoperative prognosis and adjuvant TACE benefit in HCC patients. These tools can assist in building a more customized method of HCC treatment.

LINC00152 mediates CD8+ T-cell infiltration in gastric cancer through binding to EZH2 and regulating the CXCL9, 10/CXCR3 axis

This study aimed to annotate the role of long intergenic non-coding RNA 152 (LINC00152) in CD8⁺ T cells mediated immune responses in gastric cancer (GC) and the underlying mechanism. LINC00152 expression levels were detected through RT-PCR. For tumor engraftment, HGC-27 cells that received LINC00152 shRNA, LINC00152 overexpression vectors, enhancer of zeste homolog 2 (EZH2) shRNA or combination transfection were injected into mice. Chromatin immunoprecipitation (ChIP) assay was used to explore the interaction between LINC00152, Cys-X-cys ligand 9 (CXCL9) and Cys-X-cys ligand 10 (CXCL10). Flow cytometry was adopted to measure the CD8⁺ T-cell infiltration in tumor issue. In this study, we found increased LINC00152 expression levels are positively associated with the poor prognosis of GC patients and negatively associated with the CD8 levels. ChIP assay verified that LINC00152 recruits EZH2 to the promoters of CXCL9 and CXCL10, thus the silencing of LINC00152 promoted the production of CXCL9 and CXCL10. Knockdown of LINC00152 suppressed tumor cells growth in vivo and in vitro, increased tumor-infiltrating CD8⁺ T cells numbers and promoted the expression of CXCL9, CXCL10 and C-X-C Motif Chemokine Receptor 3 (CXCR3) in xenograft tumors. While CD8⁺ T cell depletion reversed the tumor suppression effect of LINC00152 silence. Besides, the silencing of EZH2 partly inhibited the promotion effect LINC00152 on tumor growth. Our study indicated that LINC00152 inhibition suppressed the tumor progress may through promoting CD8⁺ T-cell infiltration.

Resistance mechanisms to checkpoint inhibitors

Although multiple immune checkpoint inhibitors (ICI) have been identified and tested in the clinic, antibodies blocking the PD-1/PD-L1 axis have produced the greatest impact on cancer treatment. Many potential mechanisms of treatment failure have been proposed from pre-clinical animal and human translational studies. Pre-clinical studies and clinical trials are underway to better understand how resistance arises and to develop strategies that can circumvent these resistance mechanisms and sensitize patients to anti-PD1/PD-L1 to improve clinical outcomes.

The role of exosomal PD-L1 in tumor immunotherapy

Exosomes are bioactive lipid bilayer vesicles released by most cells to mediate intercellular signal communication. Tumor cells release exosomes transmitting signals cell-to-cell and between cells and organs, which will promote tumor angiogenesis, regulate tumor stromal response, immune response, and enhance tumor cells resistance, while exosomes-derived from immune cells in tumor microenvironment play a key role in inhibiting tumor growth and killing tumor cells. Programmed cell death protein 1 (PD-1) combined with Programmed cell death protein ligand 1(PD-L1) can inhibit the activation of T cells, for tumor cells achieve immune escape by overexpressing PD-L1 and binding PD-1 on T cells. The use of anti-PD-1 / PD-L1 antibodies prevents their binding to a certain extent and partially restores T cell's activity. This article mainly discusses the role of exosomal PD-L1 in tumor progression and therapeutic efficacy after application of clinical antibodies, as well as the relation between different reactivity and immunity set points in cancer patients of different races, with different types and at different stages. Besides, we propose that exosomal PD-L1 may become targets for anti-PD-1 / PD-L1 antibody therapy, biomarkers for liquid biopsy, and drug carriers.

Immune Checkpoint Inhibitors in Triple Negative Breast Cancer Treatment: Promising Future Prospects

Immunotherapy has emerged as the fifth pillar of cancer treatment alongside surgery, radiotherapy, chemotherapy, and targeted therapy. Immune checkpoint inhibitors are the current superheroes of immunotherapy, unleashing a patient's own immune cells to kill tumors and revolutionizing cancer treatment in a variety of cancers. Although breast cancer was historically believed to be immunologically silent, treatment with immune checkpoint inhibitors has been shown to induce modest responses in metastatic breast cancer. Given the inherent heterogeneity of breast tumors, this raised the question whether certain breast tumors might benefit more from immune-based interventions and which cancer cell-intrinsic and/or microenvironmental factors define the likelihood of inducing a potent and durable anti-tumor immune response. In this review, we will focus on triple negative breast cancer as immunogenic breast cancer subtype, and specifically discuss the relevance of tumor mutational burden, the plethora and diversity of tumor infiltrating immune cells in addition to the immunoscore, the presence of immune checkpoint expression, and the microbiome in defining immune checkpoint blockade response. We will highlight the current immune checkpoint inhibitor treatment options, either as monotherapy or in combination with standard-of-care treatment modalities such as chemotherapy and targeted therapy. In addition, we will look into the potential of immunotherapy-based combination strategies using immune checkpoint inhibitors to enhance both innate and adaptive immune responses, or to establish a more immune favorable environment for cancer vaccines. Finally, the review will address the need for unambiguous predictive biomarkers as one of the main challenges of immune checkpoint blockade. To conclude, the potential of immune checkpoint blockade for triple negative breast cancer treatment could be enhanced by exploration of aforementioned factors and treatment strategies thereby providing promising future prospects.

Intratumoral Plasmid IL12 Expands CD8+ T Cells and Induces a CXCR3 Gene Signature in Triple-negative Breast Tumors that Sensitizes Patients to Anti-PD-1 Therapy

PURPOSE

Triple-negative breast cancer (TNBC) is an aggressive disease with limited therapeutic options. Antibodies targeting programmed cell death protein 1 (PD-1)/PD-1 ligand 1 (PD-L1) have entered the therapeutic landscape in TNBC, but only a minority of patients benefit. A way to reliably enhance immunogenicity, T-cell infiltration, and predict responsiveness is critically needed.

PATIENTS AND METHODS

Using mouse models of TNBC, we evaluate immune activation and tumor targeting of intratumoral IL12 plasmid followed by electroporation (tavokinogene telseplasmid; Tavo). We further present a single-arm, prospective clinical trial of Tavo monotherapy in patients with treatment refractory, advanced TNBC (OMS-I140). Finally, we expand these findings using publicly available breast cancer and melanoma datasets.

RESULTS

Single-cell RNA sequencing of murine tumors identified a CXCR3 gene signature (CXCR3-GS) following Tavo treatment associated with enhanced antigen presentation, T-cell infiltration and expansion, and PD-1/PD-L1 expression. Assessment of pretreatment and posttreatment tissue from patients confirms enrichment of this CXCR3-GS in tumors from patients that exhibited an enhancement of CD8⁺ T-cell infiltration following treatment. One patient, previously unresponsive to anti-PD-L1 therapy, but who exhibited an increased CXCR3-GS after Tavo treatment, went on to receive additional anti-PD-1 therapy as their immediate next treatment after OMS-I140, and demonstrated a significant clinical response.

CONCLUSIONS

These data show a safe, effective intratumoral therapy that can enhance antigen presentation and recruit CD8 T cells, which are required for the antitumor efficacy. We identify a Tavo treatment-related gene signature associated with improved outcomes and conversion of nonresponsive tumors, potentially even beyond TNBC.

Copper-Based Nanoscale Coordination Polymers Augmented Tumor Radioimmunotherapy for Immunogenic Cell Death Induction and T-Cell Infiltration

Insufficient T-cell infiltration seriously hinders the efficacy of tumor immunotherapy. Induction of immunogenic cell death (ICD) is a potentially feasible approach to increase T-cell infiltration. Since ionizing radiation can only induce low-level ICD, this study constructs Cu-based nanoscale coordination polymers (Cu-NCPs) with mixed-valence (Cu⁺ /Cu²⁺ ), which can simultaneously and independently induce the generation of Cu⁺ -triggered hydroxyl radicals and Cu²⁺ -triggered GSH elimination, to synergize with radiation therapy for potent ICD induction. Markedly, this synergetic therapy remarkably enhances dendritic cell maturation and promotes antitumor CD8⁺ T-cell infiltration, thereby potentiating the development of checkpoint blockade immunotherapies against primary and metastatic tumors.

Ketogenic diet and ketone bodies enhance the anticancer effects of PD-1 blockade

Limited experimental evidence bridges nutrition and cancer immunosurveillance. Here, we show that ketogenic diet (KD) — or its principal ketone body, 3-hydroxybutyrate (3HB), most specifically in intermittent scheduling — induced T cell–dependent tumor growth retardation of aggressive tumor models. In conditions in which anti–PD-1 alone or in combination with anti–CTLA-4 failed to reduce tumor growth in mice receiving a standard diet, KD, or oral supplementation of 3HB reestablished therapeutic responses. Supplementation of KD with sucrose (which breaks ketogenesis, abolishing 3HB production) or with a pharmacological antagonist of the 3HB receptor GPR109A abolished the antitumor effects. Mechanistically, 3HB prevented the immune checkpoint blockade–linked upregulation of PD-L1 on myeloid cells, while favoring the expansion of CXCR3⁺ T cells. KD induced compositional changes of the gut microbiota, with distinct species such as Eisenbergiella massiliensis commonly emerging in mice and humans subjected to carbohydrate-low diet interventions and highly correlating with serum concentrations of 3HB. Altogether, these results demonstrate that KD induces a 3HB-mediated antineoplastic effect that relies on T cell–mediated cancer immunosurveillance.

Radiation Response in the Tumour Microenvironment: Predictive Biomarkers and Future Perspectives

Radiotherapy (RT) is a primary treatment modality for a number of cancers, offering potentially curative outcomes. Despite its success, tumour cells can become resistant to RT, leading to disease recurrence. Components of the tumour microenvironment (TME) likely play an integral role in managing RT success or failure including infiltrating immune cells, the tumour vasculature and stroma. Furthermore, genomic profiling of the TME could identify predictive biomarkers or gene signatures indicative of RT response. In this review, we will discuss proposed mechanisms of radioresistance within the TME, biomarkers that may predict RT outcomes, and future perspectives on radiation treatment in the era of personalised medicine.

Boiling histotripsy and in-situ CD40 stimulation improve the checkpoint blockade therapy of poorly immunogenic tumors

Background: Advanced stage cancers with a suppressive tumor microenvironment (TME) are often refractory to immune checkpoint inhibitor (ICI) therapy. Recent studies have shown that focused ultrasound (FUS) TME-modulation can synergize ICI therapy, but enhancing survival outcomes in poorly immunogenic tumors remains challenging. Here, we investigated the role of focused ultrasound based boiling histotripsy (HT) and in-situ anti-CD40 agonist antibody (αCD40) combinatorial therapy in enhancing therapeutic efficacy against ICI refractory murine melanoma. Methods: Unilateral and bilateral large (~330-400 mm3) poorly immunogenic B16F10 melanoma tumors were established in the flank regions of mice. Tumors were exposed to single local HT followed by an in-situ administration of αCD40 (HT+ αCD40: HT40). Inflammatory signatures post treatment were assessed using pan-cancer immune profiling and flow cytometry. The ability of HT40 ± ICI to enhance local and systemic effects was determined by immunological characterization of the harvested tissues, and by tumor growth delay of local and distant untreated tumors 4-6 weeks post treatment. Results: Immune profiling revealed that HT40 upregulated a variety of inflammatory markers in the tumors. Immunologically, HT40 treated tumors showed an increased population of granzyme B+ expressing functional CD8+ T cells (~4-fold) as well as an increased M1 to M2 macrophage ratio (~2-3-fold) and CD8+ T: regulatory T cell ratio (~5-fold) compared to the untreated control. Systemically, the proliferation rates of the melanoma-specific memory T cell population were significantly enhanced by HT40 treatment. Finally, the combination of HT40 and ICI therapy (anti-CTLA-4 and anti-PD-L1) caused superior inhibition of distant untreated tumors, and prolonged survival rates compared to the control. Conclusions: Data suggest that HT40 reprograms immunologically cold tumors and sensitizes them to ICI therapy. This approach may be clinically useful for treating advanced stage melanoma cancers.

Establishing standardized immune phenotyping of metastatic melanoma by digital pathology

CD8+ tumor-infiltrating T cells can be regarded as one of the most relevant predictive biomarkers in immune-oncology. Highly infiltrated tumors, referred to as inflamed (clinically "hot"), show the most favorable response to immune checkpoint inhibitors in contrast to tumors with a scarce immune infiltrate called immune desert or excluded (clinically "cold"). Nevertheless, quantitative and reproducible methods examining their prevalence within tumors are lacking. We therefore established a computational diagnostic algorithm to quantitatively measure spatial densities of tumor-infiltrating CD8+ T cells by digital pathology within the three known tumor compartments as recommended by the International Immuno-Oncology Biomarker Working Group in 116 prospective metastatic melanomas of the Swiss Tumor Profiler cohort. Workflow robustness was confirmed in 33 samples of an independent retrospective validation cohort. The introduction of the intratumoral tumor center compartment proved to be most relevant for establishing an immune diagnosis in metastatic disease, independent of metastatic site. Cut-off values for reproducible classification were defined and successfully assigned densities into the respective immune diagnostic category in the validation cohort with high sensitivity, specificity, and precision. We provide a robust diagnostic algorithm based on intratumoral and stromal CD8+ T-cell densities in the tumor center compartment that translates spatial densities of tumor-infiltrating CD8+ T cells into the clinically relevant immune diagnostic categories "inflamed", "excluded", and "desert". The consideration of the intratumoral tumor center compartment allows immune phenotyping in the clinically highly relevant setting of metastatic lesions, even if the invasive margin compartment is not captured in biopsy material.

Changes in the Tumor Immune Microenvironment during Disease Progression in Patients with Ovarian Cancer

Simple Summary

Immunotherapy has been a successful treatment for many cancers. However, no immunotherapy treatment has been approved for ovarian cancer due to low efficacy in this patient group. This study investigated the cellular and molecular changes from primary ovarian tumors, at the time of diagnosis, to recurrence, where the disease returns after surgery and chemotherapies. Here we examined the immune contexture to better understand subdued responses to immunotherapy and identify additional, potentially complimentary, therapeutic targets. Indications of the development of adaptive immune resistance during disease progression were observed, with increases in immune and stromal cell infiltration accompanied by the expression of immune suppressive markers. We observed high gene expression of the immune checkpoint genes LAG3 and HAVCR2 (TIM3) in most tumors and increased expression of the immune checkpoint genes TIGIT and CTLA4 in recurrent tumors, compared to the primaries. These markers may be potential candidates for immunotherapy targeting in ovarian cancer.

Abstract

Anti-PD1/PDL1 therapy has proven efficacious against many cancers but only reached modest objective response rates against recurrent ovarian cancer. A deeper understanding of the tumor microenvironment (TME) may reveal other immunosuppressive mechanisms that warrant investigation as immunotherapeutic targets for this challenging disease. Matched primary and recurrent tumors from patients with high-grade serous ovarian carcinoma (HGSC) were analyzed by multicolor immunohistochemistry/immunofluorescence for the presence of T cells, B cells, macrophages, and for the expression of immunosuppressive and HLA molecules. Cancer- and immune-related gene expression was assessed by NanoString analysis. Recurrent tumors showed increased infiltration by immune cells, displayed higher expression of PDL1, IDO, and HLA molecules, and contained more stromal tissue. NanoString analysis demonstrated increased expression of gene signatures related to chemokines and T cell functions in recurrent tumors. The ovarian tumors showed high gene expression of LAG3 and HAVCR2 (TIM3) and enhanced levels of TIGIT and CTLA4 in recurrent tumors compared to primary tumors. The majority of HGSC developed into a more inflamed phenotype during progression from primary to recurrent disease, including indications of adaptive immune resistance. This suggests that recurrent tumors may be particularly sensitive to inhibition of adaptive immune resistance mechanisms.

Immune Modulation in Lung Cancer: Current Concepts and Future Strategies

Cancer immunotherapy represents the most dynamic field of biomedical research currently, with thoracic immuno-oncology as a forerunner. PD-(L)1 inhibitors are already part of standard first-line treatment for both non-small-cell and small-cell lung cancer, while unprecedented 5-year survival rates of 15-25% have been achieved in pretreated patients with metastatic disease. Evolving strategies are mainly aiming for improvement of T-cell function, increase of immune activation in the tumor microenvironment (TME), and supply of tumor-reactive lymphocytes. Several novel therapeutics have demonstrated preclinical efficacy and are increasingly used in rational combinations within clinical trials. Two overarching trends dominate: extension of immunotherapy to earlier disease stages, mainly as neoadjuvant treatment, and a shift of focus towards multivalent, individualized, mutatome-based antigen-specific modalities, mainly adoptive cell therapies and cancer vaccines. The former ensures ample availability of treated and untreated patient samples, the latter facilitates deeper mechanistic insights, and both in combination build an overwhelming force that is accelerating progress and driving the greatest revolution cancer medicine has seen so far. Today, immune modulation represents the most potent therapeutic modality in oncology, the most important topic in clinical and translational cancer research, and arguably our greatest, meanwhile justified hope for achieving cure of pulmonary neoplasms and other malignancies in the next future.

Small molecules targeting the innate immune cGAS‒STING‒TBK1 signaling pathway

Multiple cancer immunotherapies including chimeric antigen receptor T cell and immune checkpoint inhibitors (ICIs) have been successfully developed to treat various cancers by motivating the adaptive anti-tumor immunity. Particularly, the checkpoint blockade approach has achieved great clinic success as evidenced by several U.S. Food and Drug Administration (FDA)-approved anti-programmed death receptor 1/ligand 1 or anti-cytotoxic T lymphocyte associated protein 4 antibodies. However, the majority of cancers have low clinical response rates to these ICIs due to poor tumor immunogenicity. Indeed, the cyclic guanosine monophosphate-adenosine monophosphate synthase‒stimulator of interferon genes‒TANK-binding kinase 1 (cGAS‒STING‒TBK1) axis is now appreciated as the major signaling pathway in innate immune response across different species. Aberrant signaling of this pathway has been closely linked to multiple diseases, including auto-inflammation, virus infection and cancers. In this perspective, we provide an updated review on the latest progress on the development of small molecule modulators targeting the cGAS‒STING‒TBK1 signaling pathway and their preclinical and clinical use as a new immune stimulatory therapy. Meanwhile, highlights on the clinical candidates, limitations and challenges, as well as future directions in this field are also discussed. Further, small molecule inhibitors targeting this signaling axis and their potential therapeutic use for various indications are discussed as well.

Rationale for concurrent chemoradiotherapy for patients with stage III non-small-cell lung cancer

When treating patients with unresectable stage III non-small-cell lung cancer (NSCLC), those with a good performance status and disease measured within a radical treatment volume should be considered for definitive concurrent chemoradiotherapy (cCRT). This guidance is based on key scientific rationale from two large Phase 3 randomised studies and meta-analyses demonstrating the superiority of cCRT over sequential (sCRT). However, the efficacy of cCRT comes at the cost of increased acute toxicity versus sequential treatment. Currently, there are several documented approaches that are addressing this drawback, which this paper outlines. At the point of diagnosis, a multidisciplinary team (MDT) approach can enable accurate assessment of patients, to determine the optimal treatment strategy to minimise risks. In addition, reviewing the Advisory Committee on Radiation Oncology Practice (ACROP) guidelines can provide clinical oncologists with additional recommendations for outlining target volume and organ-at-risk delineation for standard clinical scenarios in definitive cCRT (and adjuvant radiotherapy). Furthermore, modern advances in radiotherapy treatment planning software and treatment delivery mean that radiation oncologists can safely treat substantially larger lung tumours with higher radiotherapy doses, with greater accuracy, whilst minimising the radiotherapy dose to the surrounding healthy tissues. The combination of these advances in cCRT may assist in creating comprehensive strategies to allow patients to receive potentially curative benefits from treatments such as immunotherapy, as well as minimising treatment-related risks.

Versican and Versican-matrikines in Cancer Progression, Inflammation, and Immunity

Versican is an extracellular matrix proteoglycan with key roles in multiple facets of cancer development, ranging from proliferative signaling, evasion of growth-suppressor pathways, regulation of cell death, promotion of neoangiogenesis, and tissue invasion and metastasis. Multiple lines of evidence implicate versican and its bioactive proteolytic fragments (matrikines) in the regulation of cancer inflammation and antitumor immune responses. The understanding of the dynamics of versican deposition/accumulation and its proteolytic turnover holds potential for the development of novel immune biomarkers as well as approaches to reset the immune thermostat of tumors, thus promoting efficacy of modern immunotherapies. This article summarizes work from several laboratories, including ours, on the role of this central matrix proteoglycan in tumor progression as well as tumor-immune cell cross-talk.

Progress in research into the role of abnormal glycosylation modification in tumor immunity

In abnormal glycosylation, molecules of glucose or other carbohydrates in living organisms are inappropriately attached to proteins, which causes protein denaturation. Abnormal glycosylation modification is known to directly or indirectly affect the tumor escape process, but very few studies have been performed on whether protein glycosylation changes the structure and function of immune cells and immune molecules and thereby regulates the occurrence and development of tumor escape. Therefore, this article summarizes the effect of the immune system on tumor escape in association with the abnormal glycosylation process from an immunological perspective.

Current Clinical Applications and Future Perspectives of Immune Checkpoint Inhibitors in Non-Hodgkin Lymphoma

Cancer cells escape immune recognition by exploiting the programmed cell-death protein 1 (PD-1)/programmed cell-death 1 ligand 1 (PD-L1) immune checkpoint axis. Immune checkpoint inhibitors that target PD-1/PD-L1 unleash the properties of effector T cells that are licensed to kill cancer cells. Immune checkpoint blockade has dramatically changed the treatment landscape of many cancers. Following the cancer paradigm, preliminary results of clinical trials in lymphoma have demonstrated that immune checkpoint inhibitors induce remarkable responses in specific subtypes, most notably classical Hodgkin lymphoma and primary mediastinal B-cell lymphoma, while in other subtypes, the results vary considerably, from promising to disappointing. Lymphomas that respond to immune checkpoint inhibitors tend to exhibit tumor cells that reside in a T-cell-rich immune microenvironment and display constitutive transcriptional upregulation of genes that facilitate innate immune resistance, such as structural variations of the PD-L1 locus, collectively referred to as T-cell-inflamed lymphomas, while those lacking such characteristics are referred to as noninflamed lymphomas. This distinction is not necessarily a sine qua non of response to immune checkpoint inhibitors, but rather a framework to move the field forward with a more rational approach. In this article, we provide insights on our current understanding of the biological mechanisms of immune checkpoint evasion in specific subtypes of B-cell and T-cell non-Hodgkin lymphomas and summarize the clinical experience of using inhibitors that target immune checkpoints in these subtypes. We also discuss the phenomenon of hyperprogression in T-cell lymphomas, related to the use of such inhibitors when T cells themselves are the target cells, and consider future approaches to refine clinical trials with immune checkpoint inhibitors in non-Hodgkin lymphomas.

Stromal reaction inhibitor and immune-checkpoint inhibitor combination therapy attenuates excluded-type colorectal cancer in a mouse model

Despite recent advances in cancer immunotherapy, the efficacy of colorectal cancer (CRC) immunotherapy regimens is limited. This study evaluated the combined effect of an anti-PD-1 antibody and a platelet-derived growth factor receptor inhibitor (imatinib) on CRC progression using an orthotopic transplanted mouse model that reproduced the three histological phenotypes of CRC (inflamed-, excluded-, and desert-type). The frequency of each of these phenotypes in 196 human CRC tissue samples was also evaluated. Excluded-type CRC had the highest frequency in human tissue samples. In the mouse model, imatinib suppressed stromal reaction and increased sensitivity to anti-PD-1 treatment in excluded-type CRC. Antitumor effect was observed in mice with excluded-type tumors only after concomitant administration of anti-PD-1 antibody and imatinib. Immunohistological analysis revealed a reduction in stromal volume and an increase in the number of CD8-positive T cells in the tumor nest following combination therapy. RNA sequencing revealed significant activation of immune-related pathways and suppression of stromal-related pathways in transplanted tumors treated with combination therapy compared with tumors treated with anti-PD-1 antibody monotherapy. This combination therapy may prove effective for CRC cases that are unresponsive to anti-PD-1 antibody monotherapy.

Combination of Irreversible Electroporation and STING Agonist for Effective Cancer Immunotherapy

Recently, cancer immunotherapy has received attention as a viable solution for the treatment of refractory tumors. However, it still has clinical limitations in its treatment efficacy due to inter-patient tumor heterogeneity and immunosuppressive tumor microenvironment (TME). In this study, we demonstrated the triggering of anti-cancer immune responses by a combination of irreversible electroporation (IRE) and a stimulator of interferon genes (STING) agonist. Optimal electrical conditions inducing damage-associated molecular patterns (DAMPs) by immunogenic cell death (ICD) were determined through in vitro 2D and 3D cell experiments. In the in vivo syngeneic lung cancer model, the combination of IRE and STING agonists demonstrated significant tumor growth inhibition. We believe that the combination strategy of IRE and STING agonists has potential for effective cancer immunotherapy.

Current Perspectives on Immunotherapy in the Peri-Operative Setting of Muscle-Infiltrating Bladder Cancer

Patients with muscle-infiltrating bladder cancer (MIBC) present a high risk of postoperative recurrence and death from metastatic urothelial cancer despite surgical resection. Before the use of peri-operative chemotherapy, about half (52%) of patients undergoing radical cystectomy had had a relapse of tumor disease within 5 years of surgery. However, when peri-operative cisplatin-based chemotherapy is added to radical cystectomy for patients with MIBC it provides limited benefit in terms of survival, disease recurrence and development of metastases, at the expense of toxic effects. In fact, a significant proportion of patients still recurs and die to metastatic disease. Given the success of immune-oncological drugs in metastatic urothelial cancer, several trials started to test them in patients with non-metastatic MIBC either in neo-adjuvant and adjuvant setting. The preliminary results of these studies in neo-adjuvant setting are showing great promise, confirming the potential benefits of immunotherapy also in patients with non-metastatic MIBC. The aim of this review is to present an overview of developments happening on the introduction of immunotherapy in peri-operative setting in non-metastatic urothelial cancer. Moreover, an analysis of the critical issues regarding how best customize the delivery of immunotherapy to optimize efficacy and minimize the adverse effects, with particular focus on potential prognostic and predictive molecular biomarkers, is done.

IFN-Alpha-Mediated Differentiation of Dendritic Cells for Cancer Immunotherapy: Advances and Perspectives

The past decade has seen tremendous developments in novel cancer therapies through targeting immune-checkpoint molecules. However, since increasing the presentation of tumor antigens remains one of the major issues for eliciting a strong antitumor immune response, dendritic cells (DC) still hold a great potential for the development of cancer immunotherapy. A considerable body of evidence clearly demonstrates the importance of the interactions of type I IFN with the immune system for the generation of a durable antitumor response through its effects on DC. Actually, highly active DC can be rapidly generated from blood monocytes in vitro in the presence of IFN-α (IFN-DC), suitable for therapeutic vaccination of cancer patients. Here we review how type I IFN can promote the ex vivo differentiation of human DC and orientate DC functions towards the priming and expansion of protective antitumor immune responses. New epigenetic elements of control on activation of the type I IFN signal will be highlighted. We also review a few clinical trials exploiting IFN-DC in cancer vaccination and discuss how IFN-DC could be exploited for the design of effective strategies of cancer immunotherapy as a monotherapy or in combination with immune-checkpoint inhibitors or immunomodulatory drugs.

Combination Immunotherapy Using Oncolytic Virus for the Treatment of Advanced Solid Tumors

Oncolytic virus (OV) is a new therapeutic strategy for cancer treatment. OVs can selectively infect and destroy cancer cells, and therefore act as an in situ cancer vaccine by releasing tumor-specific antigens. Moreover, they can remodel the tumor microenvironment toward a T cell-inflamed phenotype by stimulating widespread host immune responses against the tumor. Recent evidence suggests several possible applications of OVs against cancer, especially in combination with immune checkpoint inhibitors. In this review, we describe the molecular mechanisms of oncolytic virotherapy and OV-induced immune responses, provide a brief summary of recent preclinical and clinical updates on this rapidly evolving field, and discuss a combinational strategy that is able to overcome the limitations of OV-based monotherapy.

NKp30 - A prospective target for new cancer immunotherapy strategies

Natural killer (NK) cells are an important arm of the innate immune system. They constitutively express the NKp30 receptor. NKp30-mediated responses are triggered by the binding of specific ligands e.g. tumour cell-derived B7-H6 and involve the secretion of cytotoxic mediators including TNF-α, IFN-γ, perforins and granzymes. The latter two constitute a target cell-directed response that is critical in the process of immunosurveillance. The structure of NKp30 is presented, focusing on the ligand-binding site, on the ligand-induced structural changes and on the experimental data available correlating structure and binding affinity. The translation of NKp30 structural changes to disease progression is also reviewed. NKp30 role in immunotherapy has been explored in chimeric antigen receptor T-cell (CAR-T) therapy. However, antibodies or small ligands targeting NKp30 have not yet been developed. The data reviewed herein unveil the key structural aspects that must be considered for drug design in order to develop novel immunotherapy approaches.

Tailoring precision immunotherapy: coming to a clinic soon?

Cell-based and antibody-based cancer immunotherapies have been widely tested across increasing numbers of cancers with an unprecedented number of successful practice-changing immunotherapy clinical trials, achieving significant survival outcomes and, characteristically, some very long-term survivors. Still, a sizeable proportion of patients, especially with solid tumours, do not benefit from immunotherapy. Here, we summarise key literature on immunotherapy biomarkers and resistance mechanisms and discuss potential strategies to overcome such resistance to improve patient outcomes. The ever-expanding understanding of the tumour-immune interaction and the tumour microenvironment allows a real opportunity to identify predictive biomarkers and tailor immune-based therapies, including designing rational combination drugs to enhance clinical outcomes, and to identify patients most likely to benefit from immunotherapy. Where there has never been a precision chemotherapy clinic in the last 70 years since its inception, even with no shortage of trying, the hope and evolution of a functional precision immunotherapy cancer clinic is a much more likely reality.

Pirfenidone facilitates immune infiltration and enhances the antitumor efficacy of PD-L1 blockade in mice

Idiopathic pulmonary fibrosis (IPF) patients have a high risk of developing lung cancer, with few treatment options available. Pirfenidone, an antifibrotic agent approved for the treatment of IPF, has been demonstrated to suppress the TGFβ signaling and modulate the expression of immune-related genes. However, for lung cancer patients with comorbid IPF, whether pirfenidone has any synergetic effect with immune checkpoint inhibitors has not been investigated. In this study, we showed that pirfenidone monotherapy attenuated tumor growth with an increased T cell inflammatory signature in tumors. Co-administration of pirfenidone with PD-L1 blockades significantly delayed the tumor growth and increased survival, compared with the effect of either treatment alone. Combination therapy promoted gene expression with a unique signature associated with innate and adaptive immune response resulted in the infiltration of immune cells and optimal T cell positioning. Furthermore, we showed a great benefit of combination therapy in alleviating the pulmonary fibrosis and reducing the tumor growth in a tumor-fibrosis model. Our results collectively demonstrated that pirfenidone facilitated antitumor immunity and enhanced the efficacy of PD-L1 blockades. It may act as an adjuvant to immunotherapy in cancer treatment, particularly, in lung cancer patients with preexisting IPF.

The Promise of Combining Radiation Therapy With Immunotherapy

The development of immunotherapy in oncology builds upon many years of scientific investigation into the cellular mechanics underlying interactions between tumor cells and immune cell populations. The past decade has brought an accelerating pace to the clinical investigation of new immunotherapy agents, particularly in the setting of metastatic disease. The integration of immunotherapy into phase 3 clinical trial design has lagged in settings of advanced locoregional disease, where combination with radiation therapy may be critical. Yet, such may be the settings where immunotherapies have their greatest potential to affect patient survival and achieve curative outcomes. In this review, we discuss the interaction of radiation with the immune system and the potential to augment antitumor immunity through combined-modality approaches that integrate radiation and immunotherapies. The dynamics of cellular and tumor response to radiation offer unique opportunities for beneficial interplay with immunotherapy that may go unrecognized with conventional screening and monotherapy clinical testing of novel pharmaceutical agents. Using immune checkpoint blockade as a primary example, we discuss recent preclinical and clinical studies that illustrate the potential synergy of such therapies in combination with radiation, and we highlight the potential clinical value of such interactions. For various immunotherapy agents, their greatest clinical effect may rest in combination with radiation, and efforts to facilitate systematic investigation of this approach are highly warranted.

Poor clinical outcomes and immunoevasive contexture in interleukin-9 abundant muscle-invasive bladder cancer

Chemotherapy and immunotherapy yield survival benefits for muscle-invasive bladder cancer (MIBC) patients, in which tumor microenvironment has been found to exert crucial roles through tipping the balance between antitumor immunity and immune evasion. Our study aims to explore the clinical significance and therapeutic role of intratumoral interleukin-9-producing cells (IL-9⁺ cells) in MIBC. Two hundred fifty-nine MIBC patients from two independent clinic centers were utilized for retrospective analysis in the study. Sixty-five fresh MIBC tumor tissues were used to evaluate the infiltration and function of immune cells via flow cytometry and ex vivo intervention experiments. Three hundred ninety-one MIBC patients of The Cancer Genome Atlas were applied for bioinformatics analysis. It was found that patients with high IL-9⁺ cells infiltration had worse overall survival and relapse-free survival. pT2 patients with low IL-9⁺ cells infiltration could benefit more from adjuvant chemotherapy (ACT). IL-9⁺ cells infiltration was correlated with decreased expression of granzyme B from CD8⁺ T cells and natural killer (NK) cells and perforin from CD8⁺ T cells, while blockade of IL-9 reactivated the antitumor capacity of both cells leading to tumor regression. Furthermore, IL-9⁺ cells infiltration could be a biomarker for predicting anti-PD-1 efficacy. In conclusion, IL-9⁺ cells infiltration could be applied as an independent prognosticator for clinical outcome and ACT/anti-PD-1 effectiveness. IL-9⁺ cells infiltration diminished the cytotoxicity of CD8⁺ T cells and NK cells resulting in tumor immune evasion, and thus targeting IL-9 could be a potential therapeutic strategy for MIBC.

Toll-Like Receptor 4 Expression on Lymphoma Cells Is Critical for Therapeutic Activity of Intratumoral Therapy With Synthetic TLR4 Agonist Glucopyranosyl Lipid A

Intratumoral (IT) injections of Glucopyranosyl lipid A (G100), a synthetic toll-like receptor 4 (TLR4) agonist formulated in a stable emulsion, resulted in T-cell inflammation of the tumor microenvironment (TME) and complete cure of 60% of mice with large established A20 lymphomas. Strong abscopal effects on un-injected lesions were observed in a bilateral tumor model and surviving mice resisted a secondary tumor challenge. Depletion of CD8 T-cells, but not CD4 or NK cells, abrogated the anti-tumor effect. Unexpectedly, TLR4 knock-out rendered A20 tumors completely non-responsive to G100. In vitro studies showed that GLA has direct effect on A20 cells, but not on A20 cells deficient for TLR4. As shown by genotyping and phenotyping analysis, G100 strongly activated antigen presentation functions in A20 cells in vitro and in vivo and induced their apoptosis in a dose dependent manner. Similarly, the TLR4 positive human mantle cell lymphoma line Mino showed in vitro activation with G100 that was blocked with an anti-TLR4 antibody. In the A20 model, direct activation of B-lymphoma cells with G100 is sufficient to induce protective CD8 T-cell responses and TLR4 expressing human B-cell lymphomas may be amenable to this therapy as well.

Tumor infiltrating lymphocytes after neoadjuvant IRX-2 immunotherapy in oral squamous cell carcinoma: Interim findings from the INSPIRE trial

OBJECTIVES

IRX-2 is a primary-cell-derived immune-restorative consisting of multiple human cytokines that act to overcome tumor-mediated immunosuppression and provide an in vivo tumor vaccination to increase tumor infiltrating lymphocytes (TILs). A randomized phase II trial was conducted of the IRX regimen 3 weeks prior to surgery consisting of an initial dose of cyclophosphamide followed by 10 days of regional perilymphatic IRX-2 cytokine injections and daily oral indomethacin, zinc and omeprazole (Regimen 1) compared to the identical regimen without IRX-2 cytokines (Regimen 2).

METHODS

A total of 96 patients with previously untreated, stage II-IV oral cavity SCC were randomized 2:1 to experimental (1) or control (2) regimens (64:32). Paired biopsy and resection specimens from 62 patients were available for creation of tissue microarray (n = 39), and multiplex immunohistology (n = 54). Increases in CD8+ TIL infiltrate scores of at least 10 cells/mm² were used to characterize immune responders (IR).

RESULTS

Regimen 1 was associated with significant increases in CD8+ infiltrates (p = 0.01) compared to Regimen 2. In p16 negative cancers (n = 26), significant increases in CD8+ and overall TILs were evident in Regimen 1 (p = 0.004, and 0.04 respectively). IRs were more frequent in Regimen 1 (74% vs 31%, p = 0.01). Multiplex immunohistology for PD-L1 expression confirmed an increase in PD-L1 H score for Regimen 1 compared to Regimen 2 (p = 0.11).

CONCLUSIONS

The findings demonstrate significant increases in TILs after perilymphatic IRX-2 injections. Three quarters of patients showed significant immune responses to IRX-2. (NCT02609386).

Repurposing Food and Drug Administration-Approved Drugs to Promote Antitumor Immunity

There has been a major resurgence of interest in immune-based approaches to treat cancer, based largely on the success of checkpoint inhibitors (anti-cytotoxic T-lymphocyte-associated antigen 4, anti-programmed cell death 1, and anti-programmed cell death ligand 1 antibodies) in several malignancies. However, not all tumors respond to checkpoint therapy, and there is clearly a need for additional approaches for enhancing tumor immunity. We summarize the critical elements necessary for mounting an efficacious T-cell response to a tumor. We cite drugs approved by the Food and Drug Administration for no-cancer indications that could be repurposed and used as part of an antitumor immune cocktail. We also list cancer drugs not initially intended to impact tumor immunity (soft repurposing) but that have been found to modulate the immune system. We highlight those drugs that might be used in combination with checkpoint inhibitors to increase response rates and survival of cancer patients. Our focus will be on drugs for which there are limited but existing human data. We cite supporting mechanistic mouse data as well. Repurposing drugs to modulate antitumor immunity is an opportunity to rapidly bring new, effective, and affordable treatments to cancer patients.