Cooperation between Constitutive and Inducible Chemokines Enables T Cell Engraftment and Immune Attack in Solid Tumors

Immunologic Signatures across Molecular Subtypes and Potential Biomarkers for Sub-Stratification in Endometrial Cancer

Current molecular classification approaches for endometrial cancer (EC) often employ multiple testing platforms. Some subtypes still lack univocal prognostic significance, highlighting the need for risk sub-stratification. The tumor immune microenvironment (TIME) is associated with tumor progression and prognosis. We sought to investigate the feasibility of classifying EC via DNA sequencing and interrogate immunologic signatures and prognostic markers across and within subtypes, respectively. Formalin-fixed paraffin-embedding (FFPE) samples from 50 EC patients underwent targeted DNA and RNA sequencing, and multiplex immunofluorescence assay for TIME. DNA sequencing classified 10%, 20%, 52%, and 18% of patients into the subtype of POLE-mutant, microsatellite instability-high (MSI-H), TP53-wt, and TP53-mutant. POLE-mutant tumors expressed the highest T-effector and IFN-γ signature and the lowest innate anti-PD-1 resistance signature among subtypes. TP53-wt revealed a converse enrichment trend for these immunologic signatures. Survival analyses using the Cancer Genome Atlas Uterine Corpus Endometrial Carcinoma (TCGA-UCEC) dataset identified associations of CCR5 (hazard ratio (HR) = 0.71, p = 0.035), TNFRSF14 (HR = 0.58, p = 0.028), and IL-10 (HR = 2.5, p = 0.012) with overall survival within MSI-H, TP53-mutant, and TP53-wt subtype, respectively. A TIME comparison between the sub-stratified subgroups of our cohort revealed upregulated tumor infiltration of immune cells in the low-risk subgroups. Our study demonstrates that targeted DNA sequencing is an effective one-stop strategy to classify EC. Immunomodulatory genes may serve as prognostic markers within subtypes.

Multiomics characteristics and immunotherapeutic potential of EZH2 in pan-cancer

Enhancer of zeste homolog 2 (EZH2) is a significant epigenetic regulator that plays a critical role in the development and progression of cancer. However, the multiomics features and immunological effects of EZH2 in pan-cancer remain unclear. Transcriptome and clinical raw data of pan-cancer samples were acquired from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, and subsequent data analyses were conducted by using R software (version 4.1.0). Furthermore, numerous bioinformatics analysis databases also reapplied to comprehensively explore and elucidate the oncogenic mechanism and therapeutic potential of EZH2 from pan-cancer insight. Finally, quantitative reverse transcription polymerase chain reaction and immunohistochemical assays were performed to verify the differential expression of EZH2 gene in various cancers at the mRNA and protein levels. EZH2 was widely expressed in multiple normal and tumor tissues, predominantly located in the nucleoplasm. Compared with matched normal tissues, EZH2 was aberrantly expressed in most cancers either at the mRNA or protein level, which might be caused by genetic mutations, DNA methylation, and protein phosphorylation. Additionally, EZH2 expression was correlated with clinical prognosis, and its up-regulation usually indicated poor survival outcomes in cancer patients. Subsequent analysis revealed that EZH2 could promote tumor immune evasion through T-cell dysfunction and T-cell exclusion. Furthermore, expression of EZH2 exhibited a strong correlation with several immunotherapy-associated responses (i.e., immune checkpoint molecules, tumor mutation burden (TMB), microsatellite instability (MSI), mismatch repair (MMR) status, and neoantigens), suggesting that EZH2 appeared to be a novel target for evaluating the therapeutic efficacy of immunotherapy.

Challenges and exploration for immunotherapies targeting cold colorectal cancer

In recent years, immune checkpoint inhibitors (ICIs) have made significant breakthroughs in the treatment of various tumors, greatly improving clinical efficacy. As the fifth most common antitumor treatment strategy for patients with solid tumors after surgery, chemotherapy, radiotherapy and targeted therapy, the therapeutic response to ICIs largely depends on the number and spatial distribution of effector T cells that can effectively identify and kill tumor cells, features that are also important when distinguishing malignant tumors from “cold tumors” or “hot tumors”. At present, only a small proportion of colorectal cancer (CRC) patients with deficient mismatch repair (dMMR) or who are microsatellite instability-high (MSI-H) can benefit from ICI treatments because these patients have the characteristics of a “hot tumor”, with a high tumor mutational burden (TMB) and massive immune cell infiltration, making the tumor more easily recognized by the immune system. In contrast, a majority of CRC patients with proficient MMR (pMMR) or who are microsatellite stable (MSS) have a low TMB, lack immune cell infiltration, and have almost no response to immune monotherapy; thus, these tumors are “cold”. The greatest challenge today is how to improve the immunotherapy response of “cold tumor” patients. With the development of clinical research, immunotherapies combined with other treatment strategies (such as targeted therapy, chemotherapy, and radiotherapy) have now become potentially effective clinical strategies and research hotspots. Therefore, the question of how to promote the transformation of “cold tumors” to “hot tumors” and break through the bottleneck of immunotherapy for cold tumors in CRC patients urgently requires consideration. Only by developing an in-depth understanding of the immunotherapy mechanisms of cold CRCs can we screen out the immunotherapy-dominant groups and explore the most suitable treatment options for individuals to improve therapeutic efficacy.

Inflammation Control and Immunotherapeutic Strategies in Comprehensive Cancer Treatment

Tumor growth and expansion are determined by the immunological tumor microenvironment (TME). Typically, early tumorigenic stages are characterized by the immune system not responding or weakly responding to the tumor. However, subsequent tumorigenic stages witness the tumor promoting its growth and metastasis by stimulating tumor-protective (pro-tumor) inflammation to suppress anti-tumor immune responses. Here, we propose the pivotal role of inflammation control in a successful anti-cancer immunotherapy strategy, implying that available and novel immunotherapeutic modalities such as inflammation modulation, antibody (Ab)-based immunostimulation, drug-mediated immunomodulation, cancer vaccination as well as adoptive cell immunotherapy and donor leucocyte transfusion could be applied in cancer patients in a synergistic manner to amplify each other's clinical effects and achieve robust anti-tumor immune reactivity. In addition, the anti-tumor effects of immunotherapy could be enhanced by thermal and/or oxygen therapy. Herein, combined immune-based therapy could prove to be beneficial for patients with advanced cancers, as aiming to provide long-term tumor cell/mass dormancy by restraining compensatory proliferation of surviving cancer cells observed after traditional anti-cancer interventions such as surgery, radiotherapy, and metronomic (low-dose) chemotherapy. We propose the Inflammatory Prognostic Score based on the blood levels of C-reactive protein and lactate dehydrogenase as well as the neutrophil-to-lymphocyte ratio to effectively monitor the effectiveness of comprehensive anti-cancer treatment.

Monocarboxylate transporter 4 inhibition potentiates hepatocellular carcinoma immunotherapy through enhancing T cell infiltration and immune attack

BACKGROUND AND AIMS

Monocarboxylate transporter (MCT) 4 is a high-affinity lactate transporter that is primarily involved in the maintenance of intracellular pH homeostasis and highly expressed in different tumors. However, the role of MCT4 in modulating immune responses against HCC remains unknown.

APPROACH AND RESULTS

In this study, we demonstrated that MCT4 was overexpressed in HCC, which was associated with poor prognosis in patients. Genetic or pharmacological inhibition of MCT4 using VB124 (a highly potent MCT4 inhibitor) suppressed HCC tumor growth in immunocompetent mice model by enhancing CD8 + T cell infiltration and cytotoxicity. Such improved immunotherapy response by MCT4 targeting was due to combined consequences characterized by the alleviated acidification of tumor microenvironment and elevated the chemokine (C-X-C motif) ligand (CXCL) 9/CXCL10 secretion induced by reactive oxygen species/NF-κB signaling pathway. Combining MCT4 inhibition improved the therapeutic benefit of anti-programmed cell death 1 immunotherapy in HCC and prolonged mice survival. Moreover, higher MCT4 expression was observed in tumor tissues from nonresponder patients with HCC receiving neoadjuvant therapy with toripalimab.

CONCLUSIONS

Our results revealed that lactate exportation by MCT4 has a tumor-intrinsic function in generating an immunosuppressive HCC environment and demonstrated the proof of the concept of targeting MCT4 in tailoring HCC immunotherapeutic approaches.

Synergistic effect of CD47 blockade in combination with cordycepin treatment against cancer

Cordycepin is widely considered a direct tumor-suppressive agent. However, few studies have investigated as the effect of cordycepin therapy on the tumor microenvironment (TME). In our present study, we demonstrated that cordycepin could weaken the function of M1-like macrophages in the TME and also contribute to macrophage polarization toward the M2 phenotype. Herein, we established a combined therapeutic strategy combining cordycepin and an anti-CD47 antibody. By using single-cell RNA sequencing (scRNA-seq), we showed that the combination treatment could significantly enhance the effect of cordycepin, which would reactivate macrophages and reverse macrophage polarization. In addition, the combination treatment could regulate the proportion of CD8⁺ T cells to prolong the progression-free survival (PFS) of patients with digestive tract malignancies. Finally, flow cytometry validated the changes in the proportions of tumor-associated macrophages (TAMs) and tumor-infiltrating lymphocytes (TILs). Collectively, our findings suggested that the combination treatment of cordycepin and the anti-CD47 antibody could significantly enhance tumor suppression, increase the proportion of M1 macrophages, and decrease the proportion of M2 macrophages. In addition, the PFS in patients with digestive tract malignancies would be prolonged by regulating CD8 ⁺ T cells.

Identification of anoikis-related molecular patterns to define tumor microenvironment and predict immunotherapy response and prognosis in soft-tissue sarcoma

Background: Soft-tissue sarcoma (STS) is a massive threat to human health due to its high morbidity and malignancy. STS also represents more than 100 histologic and molecular subtypes, with different prognosis. There is growing evidence that anoikis play a key role in the proliferation and invasion of tumors. However, the effects of anoikis in the immune landscape and the prognosis of STS remain unclear. Methods: We analyzed the genomic and transcriptomic profiling of 34 anoikis-related genes (ARGs) in patient cohort of pan-cancer and STS from The Cancer Genome Atlas (TCGA) database. Single-cell transcriptome was used to disclose the expression patterns of ARGs in specific cell types. Gene expression was further validated by real-time PCR and our own sequencing data. We established the Anoikis cluster and Anoikis subtypes by using unsupervised consensus clustering analysis. An anoikis scoring system was further built based on the differentially expressed genes (DEGs) between Anoikis clusters. The clinical and biological characteristics of different groups were evaluated. Results: The expressions of most ARGs were significantly different between STS and normal tissues. We found some common ARGs profiles across the pan-cancers. Network of 34 ARGs demonstrated the regulatory pattern and the association with immune cell infiltration. Patients from different Anoikis clusters or Anoikis subtypes displayed distinct clinical and biological characteristics. The scoring system was efficient in prediction of prognosis and immune cell infiltration. In addition, the scoring system could be used to predict immunotherapy response. Conclusion: Overall, our study thoroughly depicted the anoikis-related molecular and biological profiling and interactions of ARGs in STS. The Anoikis score model could guide the individualized management.

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

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

Cyclin G2 in macrophages triggers CTL-mediated antitumor immunity and antiangiogenesis via interferon-gamma

BACKGROUND

IFN-γ is a key mediator of tumor immunity that can induce macrophage polarization to suppress tumor growth. Cyclin G2 functions as a tumor suppressor in various cancer cells; however, its role in macrophages remains unclear. This study aimed to investigate the role and underlying mechanisms of cyclin G2 in macrophages in vitro and in vivo.

METHODS

Mouse tumor models were used to determine the effect of cyclin G2 in macrophages on tumor growth in vivo following IFN-γ treatment. Immunohistochemistry staining, immunofluorescence staining and flow cytometry were used to evaluate the number of cytotoxic T lymphocytes (CTLs) and blood vessels in the mouse tumors. Moreover, the biological roles of cyclin G2 in macrophages with regard to CTL chemotaxis, cytotoxic function, and vascular endothelial cell tube formation were assessed using in vitro functional experiments. Immunoprecipitation (IP), real-time PCR, and enzyme-linked immunosorbent assays (ELISAs) were conducted to investigate the underlying mechanisms by which cyclin G2 regulates CTLs and vascular endothelial cells.

RESULTS

We found that cyclin G2 expression was upregulated in macrophages after IFN-γ treatment. Upregulated cyclin G2 inhibited lung and colon cancer growth by increasing the secretion of its downstream effector CXCL9, which promoted CTL chemotaxis and suppressed vascular endothelial cell tube formation. Moreover, cyclin G2 increased CXCL9 mRNA levels by promoting STAT1 nuclear translocation. In addition, cyclin G2 promoted the activation of the STAT1 signaling pathway, which was dependent on PP2Ac.

CONCLUSIONS

Cyclin G2 is upregulated by IFN-γ in macrophages, promotes the secretion of CXCL9 to increase CTL chemotaxis and inhibit angiogenesis to suppress tumor growth. Our findings suggest that targeting cyclin G2 could benefit future immunotherapy.

Microdevice-based mechanical compression on living cells

Compressive stress enables the investigation of a range of cellular processes in which forces play an important role, such as cell growth, differentiation, migration, and invasion. Such solid stress can be introduced externally to study cell response and to mechanically induce changes in cell morphology and behavior by static or dynamic compression. Microfluidics is a useful tool for this, allowing one to mimic in vivo microenvironments in on-chip culture systems where force application can be controlled spatially and temporally. Here, we review the mechanical compression applications on cells with a broad focus on studies using microtechnologies and microdevices to apply cell compression, in comparison to off-chip bulk systems. Due to their unique features, microfluidic systems developed to apply compressive forces on single cells, in 2D and 3D culture models, and compression in cancer microenvironments are emphasized. Research efforts in this field can help the development of mechanoceuticals in the future.

The role of interferons in ovarian cancer progression: Hinderer or promoter?

Ovarian cancer (OC) is a common gynecologic malignancy with poor prognosis and high mortality. Changes in the OC microenvironment are closely related to the genesis, invasion, metastasis, recurrence, and drug-resistance. The OC microenvironment is regulated by Interferons (IFNs) known as a type of important cytokines. IFNs have a bidirectional regulation for OC cells growth and survival. Meanwhile, IFNs positively regulate the recruitment, differentiation and activation of immune cells. This review summarizes the secretion and the role of IFNs. In particular, we mainly elucidate the actions played by IFNs in various types of therapy. IFNs assist radiotherapy, targeted therapy, immunotherapy and biotherapy for OC, except for some IFN pathways that may cause chemo-resistance. In addition, we present some advances in OC treatment with the help of IFN pathways. IFNs have the ability to powerfully modulate the tumor microenvironment and can potentially provide new combination strategies for OC treatment.

EGFR is a master switch between immunosuppressive and immunoactive tumor microenvironment in inflammatory breast cancer

Inflammatory breast cancer (IBC), the most aggressive breast cancer subtype, is driven by an immunosuppressive tumor microenvironment (TME). Current treatments for IBC have limited efficacy. In a clinical trial (NCT01036087), an anti-EGFR antibody combined with neoadjuvant chemotherapy produced the highest pathological complete response rate ever reported in patients with IBC having triple-negative receptor status. We determined the molecular and immunological mechanisms behind this superior clinical outcome. Using novel humanized IBC mouse models, we discovered that EGFR-targeted therapy remodels the IBC TME by increasing cytotoxic T cells and reducing immunosuppressive regulatory T cells and M2 macrophages. These changes were due to diminishing immunosuppressive chemokine expression regulated by transcription factor EGR1. We also showed that induction of an immunoactive IBC TME by an anti-EGFR antibody improved the antitumor efficacy of an anti-PD-L1 antibody. Our findings lay the foundation for clinical trials evaluating EGFR-targeted therapy combined with immune checkpoint inhibitors in patients with cancer.

Enhancing CAR T-cell therapies against solid tumors: Mechanisms and reversion of resistance

Chimeric antigen receptor (CAR) T-cell therapy, belonging to adoptive immune cells therapy, utilizes engineered immunoreceptors to enhance tumor-specific killing. By now new generations of CAR T-cell therapies dramatically promote the effectiveness and robustness in leukemia cases. However, only a few CAR T-cell therapies gain FDA approval till now, which are applied to hematologic cancers. Targeting solid tumors through CAR T-cell therapies still faces many problems, such as tumor heterogeneity, antigen loss, infiltration inability and immunosuppressive micro-environment. Recent advances provide new insights about the mechanisms of CAR T-cell therapy resistance and give rise to potential reversal therapies. In this review, we mainly introduce existing barriers when treating solid tumors with CAR T-cells and discuss the methods to overcome these challenges.

Sources of inter-individual variability leading to significant changes in anti-PD-1 and anti-PD-L1 efficacy identified in mouse tumor models using a QSP framework

While anti-PD-1 and anti-PD-L1 [anti-PD-(L)1] monotherapies are effective treatments for many types of cancer, high variability in patient responses is observed in clinical trials. Understanding the sources of response variability can help prospectively identify potential responsive patient populations. Preclinical data may offer insights to this point and, in combination with modeling, may be predictive of sources of variability and their impact on efficacy. Herein, a quantitative systems pharmacology (QSP) model of anti-PD-(L)1 was developed to account for the known pharmacokinetic properties of anti-PD-(L)1 antibodies, their impact on CD8+ T cell activation and influx into the tumor microenvironment, and subsequent anti-tumor effects in CT26 tumor syngeneic mouse model. The QSP model was sufficient to describe the variability inherent in the anti-tumor responses post anti-PD-(L)1 treatments. Local sensitivity analysis identified tumor cell proliferation rate, PD-1 expression on CD8+ T cells, PD-L1 expression on tumor cells, and the binding affinity of PD-1:PD-L1 as strong influencers of tumor growth. It also suggested that treatment-mediated tumor growth inhibition is sensitive to T cell properties including the CD8+ T cell proliferation half-life, CD8+ T cell half-life, cytotoxic T-lymphocyte (CTL)-mediated tumor cell killing rate, and maximum rate of CD8+ T cell influx into the tumor microenvironment. Each of these parameters alone could not predict anti-PD-(L)1 treatment response but they could shift an individual mouse's treatment response when perturbed. The presented preclinical QSP modeling framework provides a path to incorporate potential sources of response variability in human translation modeling of anti-PD-(L)1.

Paving the road to make chimeric antigen receptor-T-cell therapy effective against solid tumors

The three major standard therapies, that is, surgery, chemotherapy, and radiation therapy have conventionally been applied to the treatments for cancers and have saved many patients. In addition, for intractable, refractory, or advanced malignancies that cannot be cured by the three standard therapies, immunotherapy is an important subject of basic and clinical researches. Immune checkpoint inhibitor therapy (ICI) has shown significant therapeutic efficacies on some types of tumors in large-scale randomized clinical trials, making a major impact on clinical oncology by scientifically proving and establishing the effectiveness of an immunotherapy. In 2018, ICI was awarded the Nobel Prize in Physiology or Medicine, and immunotherapy is now becoming the "fourth" standard therapy for cancers. Recently, adoptive cell therapies, in which genetically modified T cells with enhanced reactivity against tumors are infused into the patients, have been attracting considerable attention as a hopeful immunotherapy following ICI. Particularly, chimeric antigen receptor (CAR)-T-cell therapies demonstrate marked therapeutic efficacies against some hematologic malignancies, and have been approved in many countries. However, current CAR-T-cell therapy is considered to be little effective against solid tumors, which is one of the challenging issues to be overcome in CAR-T-cell therapy. In this review, we at first introduce CAR and CAR-T cell, and then focus on the recent progress of CAR-T-cell therapy against solid tumors as well as the novel concept on a role of CAR-T cells, aiming to further understandings of the novel cancer immunotherapies.

Surface-anchored tumor microenvironment-responsive protein nanogel-platelet system for cytosolic delivery of therapeutic protein in the post-surgical cancer treatment

Nanoparticle-anchored platelet systems hold great potential to act as drug carriers in post-surgical cancer treatment due to their intrinsic ability to target the bleeding sites. However, rational design is still needed to further improve its cargo release profiles to meet the cytosolic delivery of therapeutic proteins with intracellular targets. Herein, we developed a tumor microenvironment (TME)-responsive backpack-conjugated platelet system to enhance intracellular protein delivery, thereby significantly inhibiting tumor recurrence after surgery. Specifically, protein nanogels encapsulating GALA and Granzyme B (GrB) are conjugated on the platelet surface via an acid-sensitive benzoic-imine linker through a biorthogonal reaction (GALA-GNGs-P). Taking advantage of wound-tropism of platelets, GALA-GNGs-P could actively accumulate at the surgical trauma and release nanogels in response to acidic TME for promoting deep penetration. Following cellular uptake, the pore-forming peptide GALA helps nanogels escape from lysosome. Subsequently, high glutathione (GSH) concentration in tumor cytoplasm facilitates GrB release from NGs, leading to intense cell apoptosis. GALA-GNGs-P shows remarkable tumor-targeting capability, high cellular uptake, and outstanding lysosomal escaping ability, which can significantly inhibit tumor recurrence in mice models with incomplete tumor resection. Our findings indicate that platelets bioengineered with TME-responsive protein nanogels provide an option to intracellularly deliver therapeutic proteins for the post-surgical treatment of cancer. STATEMENT OF SIGNIFICANCE: Platelet-based drug delivery systems (DDSs) have gained considerable achievements in post-surgical cancer treatment. However, there is no research exploring their potential in realizing the controllable release of cargoes in the acidic tumor microenvironment (TME). Herein, we developed a TME-responsive bioengineered platelet delivery platform (GALA-GNGs-P) for achieving controllable and effective protein intracellular delivery to overcome post-surgical tumor recurrence. Our surface-anchored nanogel-platelet system has the following advantages: (i) improving the loading efficiency of therapeutic proteins, (ii) affecting no physiological function of platelets, (iii) realizing on-demand cargo release in the acidic TME, and (iv) helping proteins escape from endosomal entrapment. Our findings further explored the prospect of cellular backpack system and realized the controllable release of cargoes in the acidic TME.

RORγt agonist enhances anti-PD-1 therapy by promoting monocyte-derived dendritic cells through CXCL10 in cancers

Background

The overall response rate to checkpoint blockade remains unsatisfactory, partially due to the immune-suppressive tumor microenvironment. A retinoic acid-related orphan receptor γt (RORγt) agonist (LYC-55716) is currently used in clinical trials combined with anti-PD-1, but how the Th17 cell transcription factor RORγt enhances antitumor immunity of PD-1 in the tumor microenvironment remains elusive.

Methods

The expression of mRNA was analyzed using qPCR assays. Flow cytometry was used to sort and profile cells. Cell migration was analyzed using Transwell assays. Biacore was used to determine the binding affinity to the RORγt protein. The RORγt GAL4 cell-based reporter gene assay was used to measure activity in the RORγt driven luciferase reporter gene expression.

Results

We designed a potent and selective small-molecule RORγt agonist (8-074) that shows robust antitumor efficacy in syngeneic tumor models and improves the efficacy of anti‑PD‑1 in a murine lung cancer model. RORγt agonist treatment increased intratumoral CD8+ T cells, which were correlated with CXCL10 and monocyte-derived dendritic cells (MoDCs). In addition, the RORγt agonist promoted Type 17 T cell migration by upregulating CCL20 and CCR6 expression, and Type 17 T cell tumor infiltration. CCL20 induces MoDCs migration, and CXCL10 derived from MoDCs promotes CD8+ T cell migration.

Conclusion

Our results revealed that the RORγt agonist improved the efficacy of anti-PD-1. The RORγt agonist increased the migration of MoDCs, which increased the local levels of CXCL10, thus promoting CD8+ T cell tumor infiltration. Our findings provide the mechanistic insights implicating the RORγt agonist in immunotherapy and offer a strategy for targeting the RORγt agonist to improve PD-1 antibody efficacy in cancers.

Exploring the Correlation of Abnormal CXCL9 Expression with Immune Infiltration in Glioma and Patient Prognosis Based on TCGA and GTEx Databases

In this study, we intend to identify key immune-related genes (IRGs) in gliomas using the TCGA and GTEx databases. Following collection of the RNA-seq data of lower-grade glioma (LGG) and glioblastoma (GBM) patients from the TCGA and GTEx databases, the differentially expressed IRGs (DE-IRGs) were screened. The ESTIMATE algorithm was utilized to evaluate StromalScore and ImmuneScore of LGG and GBM samples and a multifactorial Cox risk model was constructed to identify the related risk genes. The core IRGs of LGG and GBM were screened through a PPI network, followed by exploration of their correlation with glioma prognosis. The relationship between IRGs and immune cells in LGG and GBM was detected. In vitro assays were performed to detect the effect of CXCL9 on glioma cell development. We screened 403 and 492 DE-IRGs in LGG and GBM. StromalScore and ImmuneScore were related to overall survival in LGG, but not in GBM. CXCL9 was identified as a core gene in LGG and GBM and shared association with the prognosis of gliomas. Furthermore, a correlation was found between CXCL9 and immune infiltration of LGG and GBM. Glioma cell proliferation and invasion could be inhibited by silencing of CXCL9. Overall, CXCL9 is correlated to the prognosis of glioma patients and may accelerate glioma development via immune regulation.

Modulating the tumor immune microenvironment with nanoparticles: A sword for improving the efficiency of ovarian cancer immunotherapy

With encouraging antitumor effects, immunotherapy represented by immune checkpoint blockade has developed into a mainstream cancer therapeutic modality. However, only a minority of ovarian cancer (OC) patients could benefit from immunotherapy. The main reason is that most OC harbor a suppressive tumor immune microenvironment (TIME). Emerging studies suggest that M2 tumor-associated macrophages (TAMs), T regulatory cells (Tregs), myeloid-derived suppressor cells (MDSCs), and cancer-associated fibroblasts (CAFs) are enriched in OC. Thus, reversing the suppressive TIME is considered an ideal candidate for improving the efficiency of immunotherapy. Nanoparticles encapsulating immunoregulatory agents can regulate immunocytes and improve the TIME to boost the antitumor immune response. In addition, some nanoparticle-mediated photodynamic and photothermal therapy can directly kill tumor cells and induce tumor immunogenic cell death to activate antigen-presenting cells and promote T cell infiltration. These advantages make nanoparticles promising candidates for modulating the TIME and improving OC immunotherapy. In this review, we analyzed the composition and function of the TIME in OC and summarized the current clinical progress of OC immunotherapy. Then, we expounded on the promising advances in nanomaterial-mediated immunotherapy for modulating the TIME in OC. Finally, we discussed the obstacles and challenges in the clinical translation of this novel combination treatment regimen. We believe this resourceful strategy will open the door to effective immunotherapy of OC and benefit numerous patients.

CAR-T cell combination therapy: the next revolution in cancer treatment

In recent decades, the advent of immune-based therapies, most notably Chimeric antigen receptor (CAR)-T cell therapy has revolutionized cancer treatment. The promising results of numerous studies indicate that CAR-T cell therapy has had a remarkable ability and successful performance in treating blood cancers. However, the heterogeneity and immunosuppressive tumor microenvironment (TME) of solid tumors have challenged the effectiveness of these anti-tumor fighters by creating various barriers. Despite the promising results of this therapeutic approach, including tumor degradation and patient improvement, there are some concerns about the efficacy and safety of the widespread use of this treatment in the clinic. Complex and suppressing tumor microenvironment, tumor antigen heterogeneity, the difficulty of cell trafficking, CAR-T cell exhaustion, and reduced cytotoxicity in the tumor site limit the applicability of CAR-T cell therapy and highlights the requiring to improve the performance of this treatment. With this in mind, in the last decade, many efforts have been made to use other treatments for cancer in combination with tuberculosis to increase the effectiveness of CAR-T cell therapy, especially in solid tumors. The combination therapy results have promising consequences for tumor regression and better cancer control compared to single therapies. Therefore, this study aimed to comprehensively discuss different cancer treatment methods in combination with CAR-T cell therapy and their therapeutic outcomes, which can be a helpful perspective for improving cancer treatment in the near future.

Expanding cross-presenting dendritic cells enhances oncolytic virotherapy and is critical for long-term anti-tumor immunity

Immunotherapies directly enhancing anti-tumor CD8+ T cell responses have yielded measurable but limited success, highlighting the need for alternatives. Anti-tumor T cell responses critically depend on antigen presenting dendritic cells (DC), and enhancing mobilization, antigen loading and activation of these cells represent an attractive possibility to potentiate T cell based therapies. Here we show that expansion of DCs by Flt3L administration impacts in situ vaccination with oncolytic Newcastle Disease Virus (NDV). Mechanistically, NDV activates DCs and sensitizes them to dying tumor cells through upregulation of dead-cell receptors and synergizes with Flt3L to promote anti-tumor CD8+ T cell cross-priming. In vivo, Flt3L-NDV in situ vaccination induces parallel amplification of virus- and tumor-specific T cells, including CD8+ T cells reactive to newly-described neoepitopes, promoting long-term tumor control. Cross-presenting conventional Type 1 DCs are indispensable for the anti-tumor, but not anti-viral, T cell response, and type I IFN-dependent CD4+ Th1 effector cells contribute to optimal anti-tumor immunity. These data demonstrate that mobilizing DCs to increase tumor antigen cross-presentation improves oncolytic virotherapy and that neoepitope-specific T cells can be induced without individualized, ex vivo manufactured vaccines.

The role of CXCR3 and its ligands in cancer

Chemokines are a class of small cytokines or signaling proteins that are secreted by cells. Owing to their ability to induce directional chemotaxis of nearby responding cells, they are called chemotactic cytokines. Chemokines and chemokine receptors have now been shown to influence many cellular functions, including survival, adhesion, invasion, and proliferation, and regulate chemokine levels. Most malignant tumors express one or more chemokine receptors. The CXC subgroup of chemokine receptors, CXCR3, is mainly expressed on the surface of activated T cells, B cells, and natural killer cells, and plays an essential role in infection, autoimmune diseases, and tumor immunity by binding to specific receptors on target cell membranes to induce targeted migration and immune responses. It is vital to treat infections, autoimmune diseases, and tumors. CXCR3 and its ligands, CXCL9, CXCL10, and CXCL11, are closely associated with the development and progression of many tumors. With the elucidation of its mechanism of action, CXCR3 is expected to become a new indicator for evaluating the prognosis of patients with tumors and a new target for clinical tumor immunotherapy. This article reviews the significance and mechanism of action of the chemokine receptor CXCR3 and its specific ligands in tumor development.

Tumor Immunogenic Cell Death as a Mediator of Intratumor CD8 T-Cell Recruitment

The success of anticancer treatments relies on a long-term response which can be mediated by the immune system. Thus, the concept of immunogenic cell death (ICD) describes the capacity of dying cancer cells, under chemotherapy or physical stress, to express or release danger-associated molecular patterns (DAMPs). These DAMPs are essential to activate dendritic cells (DCs) and to stimulate an antigen presentation to CD8 cytotoxic cells. Then, activated CD8 T cells exert their antitumor effects through cytotoxic molecules, an effect which is transitory due to the establishment of a feedback loop leading to T-cell exhaustion. This phenomenon can be reversed using immune checkpoint blockers (ICBs), such as anti-PD-1, PD-L1 or CTLA-4 Abs. However, the blockade of these checkpoints is efficient only if the CD8 T cells are recruited within the tumor. The CD8 T-cell chemoattraction is mediated by chemokines. Hence, an important question is whether the ICD can not only influence the DC activation and resulting CD8 T-cell activation but can also favor the chemokine production at the tumor site, thus triggering their recruitment. This is the aim of this review, in which we will decipher the role of some chemokines (and their specific receptors), shown to be released during ICD, on the CD8 T-cell recruitment and antitumor response. We will also analyze the clinical applications of these chemokines as predictive or prognostic markers or as new targets which should be used to improve patients' response.

CX3CL1 promotes cell sensitivity to ferroptosis and is associated with the tumor microenvironment in clear cell renal cell carcinoma

Background

An increasing number of studies have demonstrated that CX3CL1 is involved in the development of tumors and may thus be considered a new potential therapeutic target for them. However, the function of CX3CL1 in clear cell renal cell carcinoma (ccRCC) remains poorly defined.

Methods

The pan-cancer expression pattern and prognostic value of CX3CL1 were evaluated in this study. Moreover, the relationship of CX3CL1 expression with the tumor microenvironment, especially the tumor immune microenvironment, was analyzed. Our analyses employed public repository data. Additionally, we generated stable CX3CL1-overexpressing 786-O cells to determine the role of CX3CL1 in vitro via cell viability and transwell assays. A xenograft tumor model was used to determine the role of CX3CL1 in vivo. The association between CX3CL1 and ferroptosis sensitivity of tumor cells was assessed using Ferrostatin-1.

Results

Our findings indicated the involvement of CX3CL1 in the occurrence and development of ccRCC by acting as a tumor suppressor. We also found that ccRCC patients with high CX3CL1 expression showed better clinical outcomes than those with low CX3CL1 expression. The findings of our epigenetic study suggested that the expression of CX3CL1 in ccRCC is correlated with its DNA methylation level. Furthermore, the CX3CL1 expression level was closely related to the infiltration level of CD8+ T cells into the tumor microenvironment (TME). CX3CL1 showed different predictive values in different immunotherapy cohorts. Finally, CX3CL1 overexpression inhibited tumor cell proliferation and metastasis and promoted tumor ferroptosis sensitivity in ccRCC.

Conclusions

This study revealed the role of CX3CL1 as a tumor suppressor in ccRCC. Our findings indicated that CX3CL1 plays a crucial role in regulating the ccRCC TME and is a potential predictor of immunotherapy outcomes in ccRCC. We also found that CX3CL1 can promote ferroptosis sensitivity in ccRCC cells.

Optimized dose selective HDAC inhibitor tucidinostat overcomes anti-PD-L1 antibody resistance in experimental solid tumors

BACKGROUND

Although immune checkpoint inhibitors (ICIs) have influenced the treatment paradigm for multiple solid tumors, increasing evidence suggests that primary and adaptive resistance may limit the long-term efficacy of ICIs. New therapeutic strategies with other drug combinations are hence warranted to enhance the antitumor efficacy of ICIs. As a novel tumor suppressor, histone deacetylase (HDAC) inhibitor tucidinostat has been successfully confirmed to act against hematological malignancies. However, the underlying mechanisms of action for tucidinostat and whether it can manipulate the tumor microenvironment (TME) in solid tumors remain unclear.

METHODS

Three murine tumor models (4T1, LLC, and CT26) were developed to define the significant role of different doses of tucidinostat in TME. The immunotherapeutic effect of tucidinostat combined with anti-programmed cell death ligand 1 antibody (aPD-L1) was demonstrated. Furthermore, the effect of tucidinostat on phenotypic characteristics of peripheral blood mononuclear cells (PBMCs) from lung cancer patients was investigated.

RESULTS

With an optimized dose, tucidinostat could alter TME and promote the migration and infiltration of CD8⁺ T cells into tumors, partially by increasing the activity of C-C motif chemokine ligand 5 (CCL5) via NF-κB signaling. Moreover, tucidinostat significantly promoted M1 polarization of macrophages and increased the in vivo antitumor efficacy of aPD-L1. Tucidinostat also enhanced the expression of the costimulatory molecules on human monocytes, suggesting a novel and improved antigen-presenting function.

CONCLUSIONS

A combination regimen of tucidinostat and aPD-L1 may work synergistically to reduce tumor burden in patients with cancer by enhancing the immune function and provided a promising treatment strategy to overcome ICI treatment resistance.

Integrated Analysis of Single-Cell and Bulk RNA-Sequencing Reveals a Tissue-Resident Macrophage-Related Signature for Predicting Immunotherapy Response in Breast Cancer Patients

Immune checkpoint therapy (ICT) is among the widely used treatments for breast cancer (BC), but most patients do not respond to ICT and the availability of the predictive biomarkers is limited. Emerging evidence indicates that tissue-resident macrophages (RTMs) inhibit BC progression, suggesting that their presence may predict immunotherapy response. A single-cell RNA-sequencing analysis of BC samples was performed to identify five RTM clusters with a mixed phenotype of M1-M2 macrophages. The comprehensive results showed that a high score of each RTM cluster was associated with a high infiltration of CD8+ T cells, M1 macrophages, and dendritic cells, and improved overall survival. In addition, a low score of each RTM cluster was associated with a high infiltration of M0 macrophages, naïve B cells and Tregs, and poor overall survival. Gene signatures from each RTM cluster were significantly enriched in responders compared with nonresponders. Each RTM cluster expression was significantly higher in responders than in nonresponders. The analyses of bulk RNA-seq datasets of BC samples led to identification and validation of a gene expression signature, named RTM.Sig, which contained the related genes of RTM clusters for predicting response to immunotherapy. This study highlights RTM.Sig could provide a valuable tool for clinical decisions in administering ICT.

Tumor-associated macrophages expressing the transcription factor IRF8 promote T cell exhaustion in cancer

Tumors are populated by antigen-presenting cells (APCs) including macrophage subsets with distinct origins and functions. Here, we examined how cancer impacts mononuclear phagocytic APCs in a murine model of breast cancer. Tumors induced the expansion of monocyte-derived tumor-associated macrophages (TAMs) and the activation of type 1 dendritic cells (DC1s), both of which expressed and required the transcription factor interferon regulatory factor-8 (IRF8). Although DC1s mediated cytotoxic T lymphocyte (CTL) priming in tumor-draining lymph nodes, TAMs promoted CTL exhaustion in the tumor, and IRF8 was required for TAMs' ability to present cancer cell antigens. TAM-specific IRF8 deletion prevented exhaustion of cancer-cell-reactive CTLs and suppressed tumor growth. Tumors from patients with immune-infiltrated renal cell carcinoma had abundant TAMs that expressed IRF8 and were enriched for an IRF8 gene expression signature. Furthermore, the TAM-IRF8 signature co-segregated with CTL exhaustion signatures across multiple cancer types. Thus, CTL exhaustion is promoted by TAMs via IRF8.

Inhibiting DNA methylation and RNA editing upregulates immunogenic RNA to transform the tumor microenvironment and prolong survival in ovarian cancer

BACKGROUND

Novel therapies are urgently needed for ovarian cancer (OC), the fifth deadliest cancer in women. Preclinical work has shown that DNA methyltransferase inhibitors (DNMTis) can reverse the immunosuppressive tumor microenvironment in OC. Inhibiting DNA methyltransferases activate transcription of double-stranded (ds)RNA, including transposable elements. These dsRNAs activate sensors in the cytoplasm and trigger type I interferon (IFN) signaling, recruiting host immune cells to kill the tumor cells. Adenosine deaminase 1 (ADAR1) is induced by IFN signaling and edits mammalian dsRNA with an A-to-I nucleotide change, which is read as an A-to-G change in sequencing data. These edited dsRNAs cannot be sensed by dsRNA sensors, and thus ADAR1 inhibits the type I IFN response in a negative feedback loop. We hypothesized that decreasing ADAR1 editing would enhance the DNMTi-induced immune response.

METHODS

Human OC cell lines were treated in vitro with DNMTi and then RNA-sequenced to measure RNA editing. Adar1 was stably knocked down in ID8 Trp53^-/- mouse OC cells. Control cells (shGFP) or shAdar1 cells were tested with mock or DNMTi treatment. Tumor-infiltrating immune cells were immunophenotyped using flow cytometry and cell culture supernatants were analyzed for secreted chemokines/cytokines. Mice were injected with syngeneic shAdar1 ID8 Trp53^-/- cells and treated with tetrahydrouridine/DNMTi while given anti-interferon alpha and beta receptor 1, anti-CD8, or anti-NK1.1 antibodies every 3 days.

RESULTS

We show that ADAR1 edits transposable elements in human OC cell lines after DNMTi treatment in vitro. Combining ADAR1 knockdown with DNMTi significantly increases pro-inflammatory cytokine/chemokine production and sensitivity to IFN-β compared with either perturbation alone. Furthermore, DNMTi treatment and Adar1 loss reduces tumor burden and prolongs survival in an immunocompetent mouse model of OC. Combining Adar1 loss and DNMTi elicited the most robust antitumor response and transformed the immune microenvironment with increased recruitment and activation of CD8+ T cells.

CONCLUSION

In summary, we showed that the survival benefit from DNMTi plus ADAR1 inhibition is dependent on type I IFN signaling. Thus, epigenetically inducing transposable element transcription combined with inhibition of RNA editing is a novel therapeutic strategy to reverse immune evasion in OC, a disease that does not respond to current immunotherapies.

Identification of Hypoxia-Related Prognostic Signature and Competing Endogenous RNA Regulatory Axes in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common type of liver cancer and one of the highly lethal diseases worldwide. Hypoxia plays an important role in the development and prognosis of HCC. This study aimed to construct a new hypoxia-related prognosis signature and investigate its potential ceRNA axes in HCC. RNA profiles and hypoxia genes were downloaded, respectively, from the Cancer Genome Atlas hepatocellular carcinoma database and Gene Set Enrichment Analysis website. Cox regression analyses were performed to select the prognostic genes and construct the risk model. The ENCORI database was applied to build the lncRNA-miRNA-mRNA prognosis-related network. The TIMER and CellMiner databases were employed to analyze the association of gene expression in ceRNA with immune infiltration and drug sensitivity, respectively. Finally, the co-expression analysis was carried out to construct the potential lncRNA/miRNA/mRNA regulatory axes. We obtained a prognostic signature including eight hypoxia genes (ENO2, KDELR3, PFKP, SLC2A1, PGF, PPFIA4, SAP30, and TKTL1) and further established a hypoxia-related prognostic ceRNA network including 17 lncRNAs, six miRNAs, and seven mRNAs for hepatocellular carcinoma. Then, the analysis of immune infiltration and drug sensitivity showed that gene expression in the ceRNA network was significantly correlated with the infiltration abundance of multiple immune cells, the expression level of immune checkpoints, and drug sensitivity. Finally, we identified three ceRNA regulatory axes (SNHG1/miR-101-3p/PPFIA4, SNHG1/miR-101-3p/SAP30, and SNHG1/miR-101-3p/TKTL1) associated with the progression of HCC under hypoxia. Here, we constructed a prognosis gene signature and a ceRNA network related to hypoxia for hepatocellular carcinoma. Among the ceRNA network, six highly expressed lncRNAs (AC005540.1, AC012146.1, AC073529.1, AC090772.3, AC138150.2, AL390728.6) and one highly expressed mRNA (PPFIA4) were the potential biomarkers of hepatocellular carcinoma which we firstly reported. The three predicted hypoxia-related regulatory axes may play a vital role in the progression of hepatocellular carcinoma.

EZH2 as a Prognostic Factor and Its Immune Implication with Molecular Characterization in Prostate Cancer: An Integrated Multi-Omics in Silico Analysis

Prostate cancer (PCa) is a type of potentially fatal malignant tumor. Immunotherapy has shown a lot of potential for various types of solid tumors, but the benefits have been less impressive in PCa. Enhancer of zeste homolog 2 (EZH2) is one of the three core subunits of the polycomb repressive complex 2 that has histone methyltransferase activity, and the immune effects of EZH2 in PCa are still unclear. The purpose of this study was to explore the potential of EZH2 as a prognostic factor and an immune therapeutic biomarker for PCa, as well as the expression pattern and biological functions. All analyses in this study were based on publicly available databases, mainly containing Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), UCSCXenaShiny, and TISIDB. We performed differential expression analysis, developed a prognostic model, and explored potential associations between EZH2 and DNA methylation modifications, tumor microenvironment (TME), immune-related genes, tumor mutation burden (TMB), tumor neoantigen burden (TNB), and representative mismatch repair (MMR) genes. We also investigated the molecular and immunological characterizations of EZH2. Finally, we predicted immunotherapeutic responses based on EZH2 expression levels. We found that EZH2 was highly expressed in PCa, was associated with a poor prognosis, and may serve as an independent prognostic factor. EZH2 expression in PCa was associated with DNA methylation modifications, TME, immune-related genes, TMB, TNB, and MMR. By gene set enrichment analysis and gene set variation analysis, we found that multiple functions and pathways related to tumorigenesis, progression, and immune activation were enriched. Finally, we inferred that immunotherapy may be more effective for PCa patients with low EZH2 expression. In conclusion, our study showed that EZH2 could be a potentially efficient predictor of prognosis and immune response in PCa patients.

Rethinking the chemokine cascade in brain metastasis: Preventive and therapeutic implications

Brain metastasis (BrM) is one of the major causes of death in cancer patients and is associated with an estimated 10-40 % of total cancer cases. The survival rate of brain metastatic patients has not improved due to intratumor heterogeneity, the survival adaptations of brain homing metastatic cells, and the lack of understanding of underlying molecular mechanisms that limit the availability of effective therapies. The heterogeneous population of immune cells and tumor-initiating cells or cancer stem cells in the tumor microenvironment (TME) release various factors, such as chemokines that upon binding to their cognate receptors enhance tumor growth at primary sites and help tumor cells metastasize to the brain. Furthermore, brain metastatic sites have unique heterogeneous microenvironment that fuels cancer cells in establishing BrM. This review explores the crosstalk of chemokines with the heterogeneous TME during the progression of BrM and recognizes potential therapeutic approaches. We also discuss and summarize different targeted, immunotherapeutic, chemotherapeutic, and combinatorial strategies (with chemo-/immune- or targeted-therapies) to attenuate chemokines mediated BrM.

A promising research direction for colorectal cancer immunotherapy: The regulatory mechanism of CCL5 in colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide, with high morbidity and mortality rates worldwide. Therefore, there is an urgent need to develop more effective treatments for CRC patients. In recent years, there has been some success in the immunotherapy of tumors, and immunotherapy has been used in many solid tumors including CRC. To date, the clinical efficacy of immunotherapy for CRC is limited, so more effective immunotherapy methods need to be explored. In patients with CRC, the CC chemokine CCL5 plays a role in the development of CRC and the recruitment and activation of immune cells, suggesting that it has potential for immunotherapy. This review mainly introduces the latest advances in the study of CCL5 acting as a marker of CRC and related mechanisms of immunotherapy, as well as the latest understanding of how CCL5 is involved in the invasion and development of CRC.

Current landscape and perspective of oncolytic viruses and their combination therapies

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Oncolytic virotherapy has become an important branch of cancer immunotherapy in clinical practice.

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Multiple viruses can be engineered to be OVs and armed with anticancer genes to enhance their efficacy.

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OVs can reshape TME and produce synergistic anticancer efficacy when combined with other therapies.

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Safety and effectiveness are the main direction of future research and development of OVs.

Oncolytic virotherapy has become an important strategy in cancer immunotherapy. Oncolytic virus (OV) can reshape the tumor microenvironment (TME) through its replication-mediated oncolysis and transgene-produced anticancer effect, inducing an antitumor immune response and creating favorable conditions for the combination of other therapeutic measures. Extensive preclinical and clinical data have suggested that OV-based combination therapy has definite efficacy and promising prospects. Recently, several clinical trials of oncolytic virotherapy combined with immunotherapy have made breakthroughs. This review comprehensively elaborates the OV types and their targeting mechanisms, the selection of anticancer genes armed in OVs, and the therapeutic modes of action and strategies of OVs to provide a theoretical basis for the better design and construction of OVs and the optimization of OV-based therapeutic strategies.

Immunobiology of high-grade serous ovarian cancer: lessons for clinical translation

Treatment of high-grade serous ovarian cancer (HGSOC) remains challenging. Although HGSOC can potentially be responsive to immunotherapy owing to endogenous immunity at the molecular or T cell level, immunotherapy for this disease has fallen short of expectations to date. This Review proposes a working classification for HGSOC based on the presence or absence of intraepithelial T cells, and elaborates the putative mechanisms that give rise to such immunophenotypes. These differences might explain the failures of existing immunotherapies, and suggest that rational therapeutic approaches tailored to each immunophenotype might meet with improved success. In T cell-inflamed tumours, treatment could focus on mobilizing pre-existing immunity and strengthening the activation of T cells embedded in intraepithelial tumour myeloid niches. Conversely, in immune-excluded and immune-desert tumours, treatment could focus on restoring inflammation by reprogramming myeloid cells, stromal cells and vascular epithelial cells. Poly(ADP-ribose) polymerase (PARP) inhibitors, low-dose radiotherapy, epigenetic drugs and anti-angiogenesis therapy are among the tools available to restore T cell infiltration in HGSOC tumours and could be implemented in combination with vaccines and redirected T cells.

Specific targeting of glioblastoma with an oncolytic virus expressing a cetuximab-CCL5 fusion protein via innate and adaptive immunity

Chemokines such as C-C motif ligand 5 (CCL5) regulate immune cell trafficking in the tumor microenvironment (TME) and govern tumor development, making them promising targets for cancer therapy. However, short half-lives and toxic off-target effects limit their application. Oncolytic viruses (OVs) have become attractive therapeutic agents. Here, we generate an oncolytic herpes simplex virus type 1 (oHSV) expressing a secretable single-chain variable fragment of the epidermal growth factor receptor (EGFR) antibody cetuximab linked to CCL5 by an Fc knob-into-hole strategy that produces heterodimers (OV-Cmab-CCL5). OV-Cmab-CCL5 permits continuous production of CCL5 in the TME, as it is redirected to EGFR+ glioblastoma (GBM) tumor cells. OV-Cmab-CCL5 infection of GBM significantly enhances the migration and activation of natural killer cells, macrophages and T cells; inhibits tumor EGFR signaling; reduces tumor size; and prolongs survival of GBM-bearing mice. Collectively, our data demonstrate that OV-Cmab-CCL5 offers a promising approach to improve OV therapy for solid tumors.

Migratory Engineering of T Cells for Cancer Therapy

Adoptive cell therapy (ACT) and chimeric antigen receptor (CAR) T cell therapy in particular represents an adaptive, yet versatile strategy for cancer treatment. Convincing results in the treatment of hematological malignancies have led to FDA approval for several CAR T cell therapies in defined refractory diseases. In contrast, the treatment of solid tumors with adoptively transferred T cells has not demonstrated convincing efficacy in clinical trials. One of the main reasons for ACT failure in solid tumors is poor trafficking or access of transferred T cells to the tumor site. Tumors employ a variety of mechanisms shielding themselves from immune cell infiltrates, often translating to only fractions of transferred T cells reaching the tumor site. To overcome this bottleneck, extensive efforts are being undertaken at engineering T cells to improve ACT access to solid tumors. In this review, we provide an overview of the immune cell infiltrate in human tumors and the mechanisms tumors employ toward immune exclusion. We will discuss ways in which T cells can be engineered to circumvent these barriers. We give an outlook on ongoing clinical trials targeting immune cell migration to improve ACT and its perspective in solid tumors.

B3GALT4 remodels the tumor microenvironment through GD2-mediated lipid raft formation and the c-met/AKT/mTOR/IRF-1 axis in neuroblastoma

BACKGROUND

Beta-1,3-galactosyltransferase-4 (B3GALT4) plays a critical regulatory role in tumor biology. However, the role of B3GALT4 in modulating the tumor microenvironment (TME) of neuroblastoma (NB) remains unknown.

METHODS

Public datasets and clinical NB samples were collected to evaluate the expression and clinical significance of GD2 and B3GALT4 in NB patients. CCK-8, colony formation, and transwell assays and experiments in tumor-bearing mouse models were conducted to investigate the function of B3GALT4. Flow cytometry, ELISA, immunohistochemistry, immunofluorescence, western blotting, and chemotaxis assays were conducted to ascertain the immunomodulatory mechanism of B3GALT4. The combined therapeutic effect of the lipid raft inhibitor MβCD and anti-GD2 mAb was validated in a murine model of NB.

RESULTS

GD2 was overexpressed in NB tissues and high expression of GD2 was associated with poor prognosis in NB patients. B3GALT4 was downregulated in NB tissues, and low expression of B3GALT4 indicated poor prognosis in NB patients. Silencing B3GALT4 significantly enhanced tumor progression both in vitro and in vivo. Meanwhile, the overexpression of B3GALT4 increased the recruitment of CD8⁺ T lymphocytes via the chemokines CXCL9 and CXCL10. Additionally, B3GALT4 regulated NB-cell GD2 expression and lipid raft formation. Mechanistically, B3GALT4 regulated the expression of CXCL9 and CXCL10 via the c-Met signaling in the lipid rafts and the downstream AKT/mTOR/IRF-1 pathway. The lipid raft inhibitor, MβCD, attenuated B3GALT4 deficiency-induced tumor progression and immune evasion. Last, MβCD combined with anti-GD2 mAb treatment significantly enhanced the antitumor effect and the infiltration of CD8⁺ T cells.

CONCLUSIONS

Upregulation of B3GALT4 promotes the secretion of CXCL9 and CXCL10 to recruit CD8⁺ T lymphocytes via the GD2-mediated lipid rafts and the c-Met/AKT/mTOR/IRF-1 pathway. Moreover, lipid raft inhibitors may enhance the efficacy of anti-GD2 immunotherapy for NB.

FLASH X-ray spares intestinal crypts from pyroptosis initiated by cGAS-STING activation upon radioimmunotherapy

DNA-damaging treatments such as radiotherapy (RT) have become promising to improve the efficacy of immune checkpoint inhibitors by enhancing tumor immunogenicity. However, accompanying treatment-related detrimental events in normal tissues have posed a major obstacle to radioimmunotherapy and present new challenges to the dose delivery mode of clinical RT. In the present study, ultrahigh dose rate FLASH X-ray irradiation was applied to counteract the intestinal toxicity in the radioimmunotherapy. In the context of programmed cell death ligand-1 (PD-L1) blockade, FLASH X-ray minimized mouse enteritis by alleviating CD8⁺ T cell-mediated deleterious immune response compared with conventional dose rate (CONV) irradiation. Mechanistically, FLASH irradiation was less efficient than CONV X-ray in eliciting cytoplasmic double-stranded DNA (dsDNA) and in activating cyclic GMP-AMP synthase (cGAS) in the intestinal crypts, resulting in the suppression of the cascade feedback consisting of CD8⁺ T cell chemotaxis and gasdermin E-mediated intestinal pyroptosis in the case of PD-L1 blocking. Meanwhile, FLASH X-ray was as competent as CONV RT in boosting the antitumor immune response initiated by cGAS activation and achieved equal tumor control in metastasis burdens when combined with anti-PD-L1 administration. Together, the present study revealed an encouraging protective effect of FLASH X-ray upon the normal tissue without compromising the systemic antitumor response when combined with immunological checkpoint inhibitors, providing the rationale for testing this combination as a clinical application in radioimmunotherapy.

Exploring the immunomodulatory role of virtual memory CD8+ T cells: Role of IFN gamma in tumor growth control

Virtual memory CD8⁺ T cells (T_VM) have been described as cells with a memory-like phenotype but without previous antigen (Ag) exposure. T_VM cells have the ability to respond better to innate stimuli rather than by TCR engagement, producing large amounts of interferon gamma (IFNγ) after stimulation with interleukin (IL)-12 plus IL-18. As a result of the phenotypic similarity, T_VM cells have been erroneously included in the central memory T cell subset for many years. However, they can now be discriminated via the CD49d receptor, which is up-regulated only on conventional memory T cells (T_MEM) and effector T cells (T_EFF) after specific cognate Ag recognition by a TCR. In this work we show that systemic expression of IL-12 plus IL-18 induced an alteration in the normal T_VM vs T_MEM/T_EFF distribution in secondary lymphoid organs and a preferential enrichment of T_VM cells in the melanoma (B16) and the pancreatic ductal adenocarcinoma (KPC) tumor models. Using our KPC bearing OT-I mouse model, we observed a significant increase in CD8⁺ T cell infiltrating the tumor islets after IL-12+IL-18 stimulation with a lower average speed when compared to those from control mice. This finding indicates a stronger interaction of T cells with tumor cells after cytokine stimulation. These results correlate with a significant reduction in tumor size in both tumor models in IL-12+IL-18-treated OT-I mice compared to control OT-I mice. Interestingly, the absence of IFNγ completely abolished the high antitumor capacity induced by IL-12+IL-18 expression, indicating an important role for these cytokines in early tumor growth control. Thus, our studies provide significant new information that indicates an important role of T_VM cells in the immune response against cancer.

Single-Cell RNA sequencing reveals immune cell dynamics and local intercellular communication in acute murine cardiac allograft rejection

Rationale: Transplant rejection is a major impediment to long-term allograft survival, in which the actions of immune cells are of fundamental importance. However, the immune cell dynamics and local intercellular communication of acute cardiac allograft rejection are not completely clear.

Methods: Here we performed single-cell RNA sequencing on CD45⁺ immune cells isolated from cardiac grafts and spleens in a model of murine heterotopic heart transplantation. Moreover, we applied unsupervised clustering, functional enrichment analysis, cell trajectory construction and intercellular communication analysis to explore the immune cell dynamics and local intercellular communication of acute cardiac allograft rejection at single-cell level. The effect of CXCR3 antagonist and neutralizing antibody against its ligand on allograft rejection and T cell function was evaluated in murine heart transplantation model.

Results: We presented the immune cell landscape of acute murine cardiac allograft rejection at single-cell resolution, and uncovered the functional characteristics and differentiation trajectory of several alloreactive cell subpopulations, including Mki67^hi CTLs, Ccl5^hi CTLs, activated Tregs and alloreactive B cells. We demonstrated local intercellular communication and revealed the upregulation of CXCR3 and its ligands in cardiac allografts. Finally, CXCR3 blockade significantly suppressed acute cardiac allograft rejection and inhibited the alloreactive T cell function.

Conclusions: These results provide a new insight into the immune cell dynamics and local intercellular communication of acute cardiac allograft rejection, and suggest CXCR3 pathway may serve as a potential therapeutic target for transplant rejection.

Targeting the Phosphatidylserine-Immune Checkpoint with a Small-Molecule Maytansinoid Conjugate

Ligand-targeting drug delivery systems have made significant strides for disease treatments with numerous clinical approvals in this era of precision medicine. Herein, we report a class of small molecule-based immune checkpoint-targeting maytansinoid conjugates. From the ligand targeting ability, pharmacokinetics profiling, in vivo anti-pancreatic cancer, triple-negative breast cancer, and sorafenib-resistant liver cancer efficacies with quantitative mRNA analysis of treated-tumor tissues, we demonstrated that conjugate 40a not only induced lasting regression of tumor growth, but it also rejuvenated the once immunosuppressive tumor microenvironment to an “inflamed hot tumor” with significant elevation of gene expressions that were not accessible in the vehicle-treated tumor. In turn, the immune checkpoint-targeting small molecule drug conjugate from this work represents a new pharmacodelivery strategy that can be expanded with combination therapy with existing immune-oncology treatment options.

GITR Ligation Improves Anti-PD1-Mediated Restoration of Human MMR-Proficient Colorectal Carcinoma Tumor-Derived T Cells

BACKGROUND & AIMS

In contrast to mismatch repair deficient colorectal carcinoma (CRC), MMR proficient (pMMR) CRC does not respond to immune checkpoint blockade. We studied immune checkpoint stimulation via glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR) on ex vivo functionality of human tumor-infiltrating lymphocytes (TIL) isolated from pMMR primary CRC and liver metastases (CRLM).

METHODS

Using lymphocytes from resected tumor, adjacent tissues, and peripheral blood mononuclear cells (PBMC) of 132 pMMR primary CRC or CRLM patients, we determined GITR expression and the in vitro T-cell agonistic activity of recombinant GITR ligation.

RESULTS

Here, we show that GITR was overexpressed on TIL when compared with other stimulatory immune checkpoints (4-1BB, OX40). Its expression was enhanced in TIL compared with PBMC and adjacent tissues. Among CD4⁺ TIL, GITR expression was primarily expressed by CD45RA^- FoxP3^hi activated regulatory T cells. Within CD8⁺ TIL, GITR was predominantly expressed on functionally exhausted and putative tumor-reactive CD103⁺ CD39⁺ TIL. Strikingly, recombinant GITRL reinvigorated ex vivo TIL responses by significantly enhancing CD4⁺ and CD8⁺ TIL numbers. Dual treatment with GITRL and nivolumab (anti-PD1) enhanced CD8⁺ TIL expansion compared with GITRL monotherapy. Moreover, GITRL/anti-PD1 dual therapy further improved anti-PD1-mediated reinvigoration of interferon gamma secretion by exhausted CD8 TIL from primary CRC.

CONCLUSIONS

GITR is overexpressed on CD4⁺ and CD8⁺ TIL from pMMR CRC and CRLM. Agonistic targeting of GITR enhances ex vivo human TIL functionality and may therefore be a promising approach for novel monotherapy or combined immunotherapies in primary pMRR CRC and CRLM.

Malignant clonal evolution drives multiple myeloma cellular ecological diversity and microenvironment reprogramming

Background

Multiple myeloma (MM) is a heterogeneous disease with different patterns of clonal evolution and a complex tumor microenvironment, representing a challenge for clinicians and pathologists to understand and dissect the contribution and impact of polyclonality on tumor progression.

Methods

In this study, we established a global cell ecological landscape of the bone marrow (BM) from MM patients, combining single-cell RNA sequencing and single-molecule long-read genome sequencing data.

Results

The malignant mutation event was localized to the tumor cell clusters with shared mutation of ANK1 and IFITM2 in all malignant subpopulations of all MM patients. Therefore, these two variants occur in the early stage of malignant clonal origin to mediate the malignant transformation of proplasmacytes or plasmacytes to MM cells. Tumor cell stemness index score and pseudo-sequential clonal evolution analysis can be used to divide the evolution model of MM into two clonal origins: types I and IX. Notably, clonal evolution and the tumor microenvironment showed an interactive relationship, in which the evolution process is not only selected by but also reacts to the microenvironment; thus, vesicle secretion enriches immune cells with malignant-labeled mRNA for depletion. Interestingly, microenvironmental modification exhibited significant heterogeneity among patients.

Conclusions

This characterization of the malignant clonal evolution pattern of MM at the single-cell level provides a theoretical basis and scientific evidence for a personalized precision therapy strategy and further development of a potential new adjuvant strategy combining epigenetic agent and immune checkpoint blockade.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-022-01648-z.

Improving PARP inhibitor efficacy in high-grade serous ovarian carcinoma: A focus on the immune system

High-grade serous ovarian carcinoma (HGSOC) is a genomically unstable malignancy responsible for over 70% of all deaths due to ovarian cancer. With roughly 50% of all HGSOC harboring defects in the homologous recombination (HR) DNA repair pathway (e.g., BRCA1/2 mutations), the introduction of poly ADP-ribose polymerase inhibitors (PARPi) has dramatically improved outcomes for women with HR defective HGSOC. By blocking the repair of single-stranded DNA damage in cancer cells already lacking high-fidelity HR pathways, PARPi causes the accumulation of double-stranded DNA breaks, leading to cell death. Thus, this synthetic lethality results in PARPi selectively targeting cancer cells, resulting in impressive efficacy. Despite this, resistance to PARPi commonly develops through diverse mechanisms, such as the acquisition of secondary BRCA1/2 mutations. Perhaps less well documented is that PARPi can impact both the tumour microenvironment and the immune response, through upregulation of the stimulator of interferon genes (STING) pathway, upregulation of immune checkpoints such as PD-L1, and by stimulating the production of pro-inflammatory cytokines. Whilst targeted immunotherapies have not yet found their place in the clinic for HGSOC, the evidence above, as well as ongoing studies exploring the synergistic effects of PARPi with immune agents, including immune checkpoint inhibitors, suggests potential for targeting the immune response in HGSOC. Additionally, combining PARPi with epigenetic-modulating drugs may improve PARPi efficacy, by inducing a BRCA-defective phenotype to sensitise resistant cancer cells to PARPi. Finally, invigorating an immune response during PARPi therapy may engage anti-cancer immune responses that potentiate efficacy and mitigate the development of PARPi resistance. Here, we will review the emerging PARPi literature with a focus on PARPi effects on the immune response in HGSOC, as well as the potential of epigenetic combination therapies. We highlight the potential of transforming HGSOC from a lethal to a chronic disease and increasing the likelihood of cure.

SQSTM1/p62 regulate breast cancer progression and metastasis by inducing cell cycle arrest and regulating immune cell infiltration

The autophagy adaptor protein SQSTM1/p62 is overexpressed in breast cancer and has been identified as a metastasis-related protein. However, the mechanism by which SQSTM1/p62 contributes to breast cancer progression and tumor microenvironment remains unclear. This study revealed that silencing SQSTM1/p62 expression suppressed breast cancer progression via regulating cell proliferation and reshaping the tumor microenvironment (TME). Here, we found that SQSTM1/p62 was overexpressed in multiple human cancer tissue types and that was correlated with poor patient overall survival (OS) and disease-free survival (DFS). Moreover, we found that short-hairpin RNA (shRNA)-mediated knockdown of p62 expression significantly inhibited cell proliferation, migration, and invasion, and promoted cell death in vitro, as well as suppressed breast cancer growth and lung metastasis in vivo. In addition, flow cytometry analysis of splenocytes and tumor infiltrating lymphocytes (TILs) indicated that the numbers of CD8α⁺ interferon (IFN)-γ⁺ cells (CTLs) and CD4⁺IFN-γ⁺ (Th1) cells were increased while those of CD4⁺IL-4⁺ (Th2) cells, tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) were decreased. RT-PCR analyses showed that the gene expression of Th1/Th2 cytokines changed in the tumor microenvironment. Silencing SQSTM1/p62 suppressed tumor cell lung metastasis. Together, our results provide strong evidence that silencing tumor cell SQSTM1/p62 inhibited tumor growth and metastasis through cell cycle arrest and TME regulation. This finding provides a novel molecular therapeutic strategy for breast cancer progression and metastasis treatment.

Paving the Way to Solid Tumors: Challenges and Strategies for Adoptively Transferred Transgenic T Cells in the Tumor Microenvironment

T cells are important players in the antitumor immune response. Over the past few years, the adoptive transfer of genetically modified, autologous T cells-specifically redirected toward the tumor by expressing either a T cell receptor (TCR) or a chimeric antigen receptor (CAR)-has been adopted for use in the clinic. At the moment, the therapeutic application of CD19- and, increasingly, BCMA-targeting-engineered CAR-T cells have been approved and have yielded partly impressive results in hematologic malignancies. However, employing transgenic T cells for the treatment of solid tumors remains more troublesome, and numerous hurdles within the highly immunosuppressive tumor microenvironment (TME) need to be overcome to achieve tumor control. In this review, we focused on the challenges that these therapies must face on three different levels: infiltrating the tumor, exerting efficient antitumor activity, and overcoming T cell exhaustion and dysfunction. We aimed to discuss different options to pave the way for potent transgenic T cell-mediated tumor rejection by engineering either the TME or the transgenic T cell itself, which responds to the environment.

Discovery and characterization of tumor antigens in hepatocellular carcinoma for mRNA vaccine development

BACKGROUND

mRNA vaccines are emerging as new targets for cancer immunotherapy. However, the potential tumor antigens for mRNA vaccine design in hepatocellular carcinoma (HCC) remain to be elucidated.

METHODS

Genetic and RNA-Seq data were obtained from TCGA and ICGC. Tumor-specific antigens (TSAs) were identified by differential expression, mutation status, HLA binding, antigen-presenting cell (APC) correlation, immune checkpoint (ICP) relevance and prognosis. Consensus clustering was used for patient classification. The molecular and immune status of TSAs and clustered patients, including prognostic ability, tumor microenvironment, tumor-related signature and tumor immune dysfunction and exclusion (TIDE), were further characterized.

RESULTS

Five dysregulated and mutated TSAs were identified in HCC (TSA5): FXYD6, JAM2, GALNT16, C7, and CCDC146. Seven immune gene modules and five immune subtypes (IS1-IS5) of HCC were identified. The immune subtypes and TSA5-related modules showed distinct molecular, cellular and clinical characteristics. According to our study, IS1 patients may be suitable for vaccination.

A novel chemokine-based signature for prediction of prognosis and therapeutic response in glioma

AIMS

Gliomas are the primary malignant brain tumor and characterized as the striking cellular heterogeneity and intricate tumor microenvironment (TME), where chemokines regulate immune cell trafficking by shaping local networks. This study aimed to construct a chemokine-based gene signature to evaluate the prognosis and therapeutic response in glioma.

METHODS

In this study, 1024 patients (699 from TCGA and 325 from CGGA database) with clinicopathological information and mRNA sequencing data were enrolled. A chemokine gene signature was constructed by combining LASSO and SVM-RFE algorithm. GO, KEGG, and GSVA analyses were performed for function annotations of the chemokine signature. Candidate mRNAs were subsequently verified through qRT-PCR in an independent cohort including 28 glioma samples. Then, through immunohistochemical staining (IHC), we detected the expression of immunosuppressive markers and explore the role of this gene signature in immunotherapy for glioma. Lastly, the Genomics of Drug Sensitivity in Cancer (GDSC) were leveraged to predict the potential drug related to the gene signature in glioma.

RESULTS

A constructed chemokine gene signature was significantly associated with poorer survival, especially in glioblastoma, IDH wildtype. It also played an independent prognostic factor in both datasets. Moreover, biological function annotations of the predictive signature indicated the gene signature was positively associated with immune-relevant pathways, and the immunosuppressive protein expressions (PD-L1, IBA1, TMEM119, CD68, CSF1R, and TGFB1) were enriched in the high-risk group. In an immunotherapy of glioblastoma cohort, we confirmed the chemokine signature showed a good predictor for patients' response. Lastly, we predicted twelve potential agents for glioma patients with higher riskscore.

CONCLUSION

In all, our results highlighted a potential 4-chemokine signature for predicting prognosis in glioma and reflected the intricate immune landscape in glioma. It also threw light on integrating tailored risk stratification with precision therapy for glioblastoma.