Mature neutrophils suppress T cell immunity in ovarian cancer microenvironment

PD-L1 restrains PD-1+Nrp1lo Treg cells to suppress inflammation-driven colorectal tumorigenesis

T cells function not only as an essential component of host cancer immunosurveillance but also as a regulator of colonic inflammation, a process that promotes colorectal cancer. Programmed death-ligand 1 (PD-L1) is a T cell-negative regulator, but its role in regulation of T cell functions in the context of colorectal cancer is unknown. We report that global deletion of Cd274 results in increased colonic inflammation, PD-1+ T cells, and inflammation-driven colorectal tumorigenesis in mice. Single-cell RNA sequencing (scRNA-seq) analysis revealed that PD-L1 suppresses subpopulations of programmed cell death protein 1 (PD-1)+Nrp1lo regulatory T (Treg) cells and interleukin (IL) 6+ neutrophils in colorectal tumor. Treg cells produce transforming growth factor (TGF) β to recruit IL6+ neutrophils. Neutrophils produce IL6 to inhibit activation of tumor-specific cytotoxic T lymphocytes (CTLs) and primary CTLs. Accordingly, IL6 blockade immunotherapy increases CTL activation and suppresses colon tumor growth in vivo. Our findings determine that PD-L1 restrains PD-1+Nrp1loTGFβ+ Treg cells to suppress IL6+ neutrophil tumor recruitment to sustain CTL activation to control inflammation-driven colorectal tumorigenesis.

The complement system as a target in cancer immunotherapy

Malignant cells are part of a complex network within the tumor microenvironment, where their interaction with host cells and soluble mediators, including complement components, is pivotal. The complement system, known for its role in immune defense and homeostasis, exhibits a dual effect on cancer progression. This dichotomy arises from its antitumoral opsonophagocytosis and cytotoxicity versus its protumoral chronic inflammation mediated by the C5a/C5aR1 axis, influencing antitumor T-cell responses. Recent studies have revealed distinct co-expression patterns of complement genes in various cancer types, correlating with prognosis. Notably, some cancers exhibit co-regulated overexpression of complement genes associated with poor prognosis, while others show favorable outcomes. However, significant intra-patient heterogeneity further complicates this classification. Moreover, the involvement of locally produced and intracellular complement proteins adds complexity to the tumor microenvironment dynamics. This review highlights the unique interplay of complement components within different cancers and patient cohorts, showing that "one size does not fit all", for complement in cancer. It summarizes the clinical trials for complement targeting in cancer, emphasizing the need for tailored therapeutic approaches. By elucidating the mechanistic basis of complement's context-dependent role, this review aims to facilitate the development of personalized cancer therapies, ultimately improving patient care and outcomes.

Predictive value of hematologic parameters and clinicopathological features of poorly differentiated thyroid carcinoma and anaplastic thyroid carcinoma

PURPOSE

Poorly differentiated thyroid carcinoma (PDTC) and anaplastic thyroid carcinoma (ATC) are rare, aggressive thyroid cancers with poor prognosis. At present, there are a limited number of research reports on PDTC and ATC. The study aimed to analysis the predictive value of hematologic parameters and clinicopathological features of PDTC and ATC.

METHODS

This study retrospectively analyzed 67 patients at Tianjin Medical University Cancer Hospital from 2007 to 2019. We analyzed the clinicopathological features and survival outcomes of PDTC and ATC.

RESULTS

This study showed that positive D-dimer, a high NLR, and a high PLR were more common in death patients. At the end of follow-up, 22 (32.8%) patients were alive at the time of study and 45 (67.2%) patients died from thyroid carcinoma. Disease-related death rates were 93.8% in ATC and 42.9% in the PDTC group. The median overall survival (OS) was 2.5 (0.3-84) months for patients with ATC, and 56 (3-113) months of PDTC patients. Univariate analysis showed that age at diagnosis and surgery were associations with OS in ATC patients, what's more, age at diagnosis, a high NLR, a high PLR, and positive D-dimer were associations with OS in PDTC patients. Multivariate analysis revealed that age at diagnosis was an independent association with OS in ATC patients.

CONCLUSIONS

The hematologic parameters and clinicopathological features may provide predictive value of prognosis for patients with PTDC and ATC.

Machine learning framework develops neutrophil extracellular traps model for clinical outcome and immunotherapy response in lung adenocarcinoma

Neutrophil extracellular traps (NETs) are novel inflammatory cell death in neutrophils. Emerging studies demonstrated NETs contributed to cancer progression and metastases in multiple ways. This study intends to provide a prognostic NETs signature and therapeutic target for lung adenocarcinoma (LUAD) patients. Consensus cluster analysis performed by 38 reported NET-related genes in TCGA-LUAD cohorts. Then, WGCNA network was conducted to investigate characteristics genes in clusters. Seven machine learning algorithms were assessed for training of the model, the optimal model was picked by C-index and 1-, 3-, 5-year ROC value. Then, we constructed a NETs signature to predict the overall survival of LUAD patients. Moreover, multi-omics validation was performed based on NETs signature. Finally, we constructed stable knockdown critical gene LUAD cell lines to verify biological functions of Phospholipid Scramblase 1 (PLSCR1) in vitro and in vivo. Two NETs-related clusters were identified in LUAD patients. Among them, C2 cluster was provided as "hot" tumor phenotype and exhibited a better prognosis. Then, WGCNA network identified 643 characteristic genes in C2 cluster. Then, Coxboost algorithm proved its optimal performance and provided a prognostic NETs signature. Multi-omics revealed that NETs signature was involved in an immunosuppressive microenvironment and predicted immunotherapy efficacy. In vitro and in vivo experiments demonstrated that knockdown of PLSCR1 inhibited tumor growth and EMT ability. Besides, cocultural assay indicated that the knockdown of PLSCR1 impaired the ability of neutrophils to generate NETs. Finally, tissue microarray (TMA) for LUAD patients verified the prognostic value of PLSCR1 expression. In this study, we focus on emerging hot topic NETs in LUAD. We provide a prognostic NETs signature and identify PLSCR1 with multiple roles in LUAD. This work can contribute to risk stratification and screen novel therapeutic targets for LUAD patients.

Intraepithelial CD15 infiltration identifies high-grade anal dysplasia in people with HIV

Men who have sex with men (MSM) with HIV are at high risk for squamous intraepithelial lesion (SIL) and anal cancer. Identifying local immunological mechanisms involved in the development of anal dysplasia could aid treatment and diagnostics. Here, we studied 111 anal biopsies obtained from 101 MSM with HIV, who participated in an anal screening program. We first assessed multiple immune subsets by flow cytometry, in addition to histological examination, in a discovery cohort. Selected molecules were further evaluated by immunohistochemistry in a validation cohort. Pathological samples were characterized by the presence of resident memory T cells with low expression of CD103 and by changes in natural killer cell subsets, affecting residency and activation. Furthermore, potentially immunosuppressive subsets, including CD15+CD16+ mature neutrophils, gradually increased as the anal lesion progressed. Immunohistochemistry verified the association between the presence of CD15 in the epithelium and SIL diagnosis for the correlation with high-grade SIL. A complex immunological environment with imbalanced proportions of resident effectors and immune-suppressive subsets characterized pathological samples. Neutrophil infiltration, determined by CD15 staining, may represent a valuable pathological marker associated with the grade of dysplasia.

Engineering strategies to safely drive CAR T-cells into the future

Chimeric antigen receptor (CAR) T-cell therapy has proven a breakthrough in cancer treatment in the last decade, giving unprecedented results against hematological malignancies. All approved CAR T-cell products, as well as many being assessed in clinical trials, are generated using viral vectors to deploy the exogenous genetic material into T-cells. Viral vectors have a long-standing clinical history in gene delivery, and thus underwent iterations of optimization to improve their efficiency and safety. Nonetheless, their capacity to integrate semi-randomly into the host genome makes them potentially oncogenic via insertional mutagenesis and dysregulation of key cellular genes. Secondary cancers following CAR T-cell administration appear to be a rare adverse event. However several cases documented in the last few years put the spotlight on this issue, which might have been underestimated so far, given the relatively recent deployment of CAR T-cell therapies. Furthermore, the initial successes obtained in hematological malignancies have not yet been replicated in solid tumors. It is now clear that further enhancements are needed to allow CAR T-cells to increase long-term persistence, overcome exhaustion and cope with the immunosuppressive tumor microenvironment. To this aim, a variety of genomic engineering strategies are under evaluation, most relying on CRISPR/Cas9 or other gene editing technologies. These approaches are liable to introduce unintended, irreversible genomic alterations in the product cells. In the first part of this review, we will discuss the viral and non-viral approaches used for the generation of CAR T-cells, whereas in the second part we will focus on gene editing and non-gene editing T-cell engineering, with particular regard to advantages, limitations, and safety. Finally, we will critically analyze the different gene deployment and genomic engineering combinations, delineating strategies with a superior safety profile for the production of next-generation CAR T-cell.

Reciprocal crosstalk between Th17 and mesothelial cells promotes metastasis-associated adhesion of ovarian cancer cells

BACKGROUND

IL-17A and TNF synergistically promote inflammation and tumorigenesis. Their interplay and impact on ovarian carcinoma (OC) progression are, however, poorly understood. We addressed this question focusing on mesothelial cells, whose interaction with tumor cells is known to play a pivotal role in transcoelomic metastasis formation.

METHODS

Flow-cytometry and immunohistochemistry experiments were employed to identify cellular sources of IL-17A and TNF. Changes in transcriptomes and secretomes were determined by bulk and single cell RNA sequencing as well as affinity proteomics. Functional consequences were investigated by microscopic analyses and tumor cell adhesion assays. Potential clinical implications were assessed by immunohistochemistry and survival analyses.

RESULTS

We identified Th17 cells as the main population of IL-17A- and TNF producers in ascites and detected their accumulation in early omental metastases. Both IL-17A and its receptor subunit IL-17RC were associated with short survival of OC patients, pointing to a role in clinical progression. IL-17A and TNF synergistically induced the reprogramming of mesothelial cells towards a pro-inflammatory mesenchymal phenotype, concomitantly with a loss of tight junctions and an impairment of mesothelial monolayer integrity, thereby promoting cancer cell adhesion. IL-17A and TNF synergistically induced the Th17-promoting cytokines IL-6 and IL-1β as well as the Th17-attracting chemokine CCL20 in mesothelial cells, indicating a reciprocal crosstalk that potentiates the tumor-promoting role of Th17 cells in OC.

CONCLUSIONS

Our findings reveal a novel function for Th17 cells in the OC microenvironment, which entails the IL-17A/TNF-mediated induction of mesothelial-mesenchymal transition, disruption of mesothelial layer integrity and consequently promotion of OC cell adhesion. These effects are potentiated by a positive feedback loop between mesothelial and Th17 cells. Together with the observed clinical associations and accumulation of Th17 cells in omental micrometastases, our observations point to a potential role in early metastases formation and thus to new therapeutic options.

Circulating myeloid populations have prognostic utility in alcohol-related liver disease

Introduction

Alcohol-related liver disease (ARLD) accounts for over one third of all deaths from liver conditions, and mortality from alcohol-related liver disease has increased nearly five-fold over the last 30 years. Severe alcohol-related hepatitis almost always occurs in patients with a background of chronic liver disease with extensive fibrosis or cirrhosis, can precipitate 'acute on chronic' liver failure and has a high short-term mortality. Patients with alcohol-related liver disease have impaired immune responses, and increased susceptibility to infections, thus prompt diagnosis of infection and careful patient management is required. The identification of early and non-invasive diagnostic and prognostic biomarkers in ARLD remains an unresolved challenge. Easily calculated predictors of infection and mortality are required for use in patients who often exhibit variable symptoms and disease severity and may not always present in a specialized gastroenterology unit.

Methods

We have used a simple haematological analyser to rapidly measure circulating myeloid cell parameters across the ARLD spectrum.

Results and Discussion

We demonstrate for the first time that immature granulocyte (IG) counts correlate with markers of disease severity, and our data suggests that elevated counts are associated with increased short-term mortality and risk of infection. Other myeloid populations such as eosinophils and basophils also show promise. Thus IG count has the potential to serve alongside established markers such as neutrophil: lymphocyte ratio as a simply calculated predictor of mortality and risk of infectious complications in patients with alcohol-related hepatitis. This would allow identification of patients who may require more intensive management.

Increased Apolipoprotein A1 Expression Correlates with Tumor-Associated Neutrophils and T Lymphocytes in Upper Tract Urothelial Carcinoma

An increased neutrophil-to-lymphocyte ratio (NLR) is a poor prognostic biomarker in various types of cancer, because it reflects the inhibition of lymphocytes in the circulation and tumors. In urologic cancers, upper tract urothelial carcinoma (UTUC) is known for its aggressive features and lack of T cell infiltration; however, the association between neutrophils and suppressed T lymphocytes in UTUC is largely unknown. In this study, we examined the relationship between UTUC-derived factors and tumor-associated neutrophils or T lymphocytes. The culture supernatant from UTUC tumor tissue modulated neutrophils to inhibit T cell proliferation. Among the dominant factors secreted by UTUC tumor tissue, apolipoprotein A1 (Apo-A1) exhibited a positive correlation with NLR. Moreover, tumor-infiltrating neutrophils were inversely correlated with tumor-infiltrating T cells. Elevated Apo-A1 levels in UTUC were also inversely associated with the population of tumor-infiltrating T cells. Our findings indicate that elevated Apo-A1 expression in UTUC correlates with tumor-associated neutrophils and T cells. This suggests a potential immunomodulatory effect on neutrophils and T cells within the tumor microenvironment, which may represent therapeutic targets for UTUC treatment.

Biomarkers of peripheral blood neutrophil extracellular traps in the diagnosis and progression of malignant tumors

BACKGROUND AND AIMS

The mortality rate associated with malignant tumors remains high and there is a lack of effective diagnostic and tumor progression markers. Neutrophil extracellular traps (NETs) can promote tumor-associated thrombosis, invasive metastasis, and inflammatory responses, but there is a lack of research on the value of measuring NETs in the peripheral blood of patients with malignancies.

METHODS

We included 263 patients with malignancies (55 gliomas, 101 ovarian, 64 colorectal, and 43 lung cancers) and 75 healthy controls in this study. We compared the levels of citrullinated histone H3 (citH3), cell-free DNA (cfDNA), and systemic inflammation-related parameters, including neutrophils, lymphocytes, monocytes, platelets, neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, platelet-to-lymphocyte ratio, systemic immune inflammation index, and systemic inflammation response index. We assessed the value of changes in NETs in peripheral blood to determine the diagnosis, venous thromboembolism, clinical staging, and systemic inflammatory response in patients with malignancy.

RESULTS

The levels of citH3 and cfDNA in peripheral blood can distinguish between healthy controls and tumor patients. The levels of citH3 and cfDNA before clinical intervention did not predict the risk of combined venous thromboembolism in oncology patients in the short-term after clinical intervention. The levels of citH3, cfDNA, and systemic inflammation-related parameters in the peripheral blood of tumor patients increased with the clinical stage. There was a correlation between cfDNA levels in peripheral blood and systemic inflammation-related parameters in tumor patients, and this correlation was more significant in patients with advanced tumors.

CONCLUSIONS

Changes in NETs in the peripheral blood differ between healthy controls and patients with malignant tumors. NETs may be involved in tumor-induced systemic inflammatory responses through interaction with circulating inflammatory cells, thus promoting tumor progression. NETs may be used as markers to assist in the diagnosis and progression of tumor malignancy.

Limitations and potential of immunotherapy in ovarian cancer

Ovarian cancer (OC) is the third most common gynecological cancer and alone has an emergence rate of approximately 308,069 cases worldwide (2020) with dire survival rates. To put it into perspective, the mortality rate of OC is three times higher than that of breast cancer and it is predicted to only increase significantly by 2040. The primary reasons for such a high rate are that the physical symptoms of OC are detectable only during the advanced phase of the disease when resistance to chemotherapies is high and around 80% of the patients that do indeed respond to chemotherapy initially, show a poor prognosis subsequently. This highlights a pressing need to develop new and effective therapies to tackle advanced OC to improve prognosis and patient survival. A major advance in this direction is the emergence of combination immunotherapeutic methods to boost CD8+ T cell function to tackle OC. In this perspective, we discuss our view of the current state of some of the combination immunotherapies in the treatment of advanced OC, their limitations, and potential approaches toward a safer and more effective response.

Scientific and clinical relevance of non-cellular tumor microenvironment components in ovarian cancer chemotherapy resistance

The tumor microenvironment (TME) components play a crucial role in cancer cells' resistance to chemotherapeutic agents. This phenomenon is exceptionally fundamental in patients with ovarian cancer (OvCa), whose outcome depends mainly on their response to chemotherapy. Until now, most reports have focused on the role of cellular components of the TME, while less attention has been paid to the stroma and other non-cellular elements of the TME, which may play an essential role in the therapy resistance. Inhibiting these components could help define new therapeutic targets and potentially restore chemosensitivity. The aim of the present article is both to summarize the knowledge about non-cellular components of the TME in the development of OvCa chemoresistance and to suggest targeting of non-cellular elements of the TME as a valuable strategy to overcome chemoresistance and to develop new therapeutic strategies in OvCA patients.

CD200/CD200R: Bidirectional Role in Cancer Progression and Immunotherapy

As an immune checkpoint molecule, CD200 serves a foundational role in regulating immune homeostasis and promoting self-tolerance. While CD200 expression occurs in various immune cell subsets and normal tissues, its aberrant expression patterns in hematologic malignancies and solid tumors have been linked to immune evasion and cancer progression under pathological conditions, particularly through interactions with its cognate receptor, CD200R. Through this CD200/CD200R signaling pathway, CD200 exerts its immunosuppressive effects by inhibiting natural killer (NK) cell activation, cytotoxic T cell functions, and M1-polarized macrophage activity, while also facilitating expansion of myeloid-derived suppressor cells (MDSCs) and Tregs. Moreover, CD200/CD200R expression has been linked to epithelial-to-mesenchymal transition and distant metastasis, further illustrating its role in cancer progression. Conversely, CD200 has also been shown to exert anti-tumor effects in certain cancer types, such as breast carcinoma and melanoma, indicating that CD200 may exert bidirectional effects on cancer progression depending on the specific tumor microenvironment (TME). Regardless, modulating the CD200/CD200R axis has garnered clinical interest as a potential immunotherapeutic strategy for cancer therapy, as demonstrated by early-phase clinical trials. However, further research is necessary to fully understand the complex interactions of CD200 in the tumor microenvironment and to optimize its therapeutic potential in cancer immunotherapy.

Complement System and the Kidney: Its Role in Renal Diseases, Kidney Transplantation and Renal Cell Carcinoma

The crosstalk among the complement system, immune cells, and mediators of inflammation provides an efficient mechanism to protect the organism against infections and support the repair of damaged tissues. Alterations in this complex machinery play a role in the pathogenesis of different diseases. Core complement proteins C3 and C5, their activation fragments, their receptors, and their regulators have been shown to be active intracellularly as the complosome. The kidney is particularly vulnerable to complement-induced damage, and emerging findings have revealed the role of complement system dysregulation in a wide range of kidney disorders, including glomerulopathies and ischemia-reperfusion injury during kidney transplantation. Different studies have shown that activation of the complement system is an important component of tumorigenesis and its elements have been proved to be present in the TME of various human malignancies. The role of the complement system in renal cell carcinoma (RCC) has been recently explored. Clear cell and papillary RCC upregulate most of the complement genes relative to normal kidney tissue. The aim of this narrative review is to provide novel insights into the role of complement in kidney disorders.

Extracellular Mechanisms of Neutrophils in Immune Cell Crosstalk

Neutrophils are professional phagocytes that provide defense against invading pathogens through phagocytosis, degranulation, generation of ROS, and the formation of neutrophil extracellular traps (NETs). Although long been considered as short-lived effector cells with limited biosynthetic activity, recent studies have revealed that neutrophils actively communicate with other immune cells. Neutrophils employ various types of soluble mediators, including granules, cytokines, and chemokines, for crosstalk with immune cells. Additionally, ROS and NETs, major arsenals of neutrophils, are utilized for intercellular communication. Furthermore, extracellular vesicles play a crucial role as mediators of neutrophil crosstalk. In this review, we highlight the extracellular mechanisms of neutrophils and their roles in crosstalk with other cells.

MUC16 stimulates neutrophils to an inflammatory and immunosuppressive phenotype in ovarian cancer

BACKGROUND

MUC16 (CA125) is a commonly used tumor marker for ovarian cancer screening and reported to be an immunosuppressive factor by acting on the sialic acid-binding immunoglobulin-like lectin-9 (Siglec-9) on the surface of natural killer cells (NK cells), B cells, and monocytes. However, the role of MUC16 on neutrophils in the tumor microenvironment remains to be further explored.

METHODS

The correlation between the proportion and count of peripheral blood cells, serum inflammatory-related factors and serum MUC16 (CA125) level in patients was constructed based on clinical samples. RNAseq data was obtained from TCGA and sequencing of ovarian cancer tissues, followed by TIMER immune cell infiltration and correlation analysis. Ovarian cancer organoid was constructed to stimulate neutrophils with immunophenotype identification by qPCR and flow cytometry. MUC16 protein stimulation to neutrophils validated the role of MUC16 under the analysis of RNA sequencing and inhibition of NK cytotoxicity in vitro.

RESULTS

The serum MUC16 level was positively correlated with the proportion and count of peripheral blood neutrophils, neutrophil-to-lymphocyte ratio (NLR) and inflammatory factors IL-6, IL-8, IL-10 and IL-2R. Siglec-9, the receptor of MUC16, was expressed on neutrophils and was positively correlated to neutrophil infiltration in ovarian cancer. After the stimulation of ovarian cancer organoids and MUC16 respectively, the proportions of CD11b+, CD66b+, and ICAM-1+ neutrophils were significantly increased, while the proportion of CXCR4+ neutrophils was slightly decreased, with increasing of of inflammatory factors MMP9, IL-8, OSM, IL-1β, TNF-α, CXCL3, and ROS. RNA-sequencing analysis revealed that inflammatory response, TNFA signaling pathway, and IL6-related pathway were upregulated in MUC16-stimulated neutrophils, accompanied by high expression of immunosuppression-related factors HHLA2, IL-6, TNFRSF9, ADORA2A, CD274 (PD-L1), and IDO1. NK cytotoxicity was decreased when treated by supernanant of MUC16-stimulated neutrophils in vitro.

CONCLUSION

MUC16 acted on neutrophils by Siglec-9 leading to an inflammatory and immunosuppressive phenotype in ovarian cancer.

Perspectives in Immunotherapy: meeting report from Immunotherapy Bridge (Naples, November 30th-December 1st, 2022)

The discovery and development of novel treatments that harness the patient's immune system and prevent immune escape has dramatically improved outcomes for patients across cancer types. However, not all patients respond to immunotherapy, acquired resistance remains a challenge, and responses are poor in certain tumors which are considered to be immunologically cold. This has led to the need for new immunotherapy-based approaches, including adoptive cell transfer (ACT), therapeutic vaccines, and novel immune checkpoint inhibitors. These new approaches are focused on patients with an inadequate response to current treatments, with emerging evidence of improved responses in various cancers with new immunotherapy agents, often in combinations with existing agents. The use of cell therapies, drivers of immune response, and trends in immunotherapy were the focus of the Immunotherapy Bridge (November 30th-December 1st, 2022), organized by the Fondazione Melanoma Onlus, Naples, Italy, in collaboration with the Society for Immunotherapy of Cancer.

CD200R signaling contributes to unfavorable tumor microenvironment through regulating production of chemokines by tumor-associated myeloid cells

CD200 is overexpressed in many solid tumors and considered as an immune checkpoint molecule dampening cancer immunity. In this study, we found that CD200R^-/- mice were significantly more potent in rejecting these CD200⁺ tumors. scRNA sequencing demonstrated that tumors from CD200R^-/- mice had more infiltration of CD4⁺ and CD8⁺ T cells, and NK cells but less infiltration of neutrophils. Antibody depletion experiments revealed that immune effector cells are crucial in inhibiting tumor growth in CD200R^-/- mice. Mechanistically, we found that CD200R signaling regulates the expression of chemokines in tumor-associated myeloid cells (TAMCs). In the absence of CD200R, TAMCs increased expression of CCL24 and resulted in increased infiltration of eosinophils, which contributes to anti-tumor activity. Overall, we conclude that CD200R signaling contributes to unfavorable TME through chemokine-dependent recruitment of immune suppressive neutrophils and exclusion of anti-cancer immune effectors. Our study has implications in developing CD200-CD200R targeted immunotherapy of solid tumors.

PD-1/PD-L1 immune checkpoint blockade in ovarian cancer: dilemmas and opportunities

Immune checkpoint inhibitors (ICIs) have revolutionized treatment in oncology. Antibodies against PD-1/PD-L1 and ICI-based combinations are under clinical investigations in multiple cancers, including ovarian cancer. However, the success of ICIs has not materialized in ovarian cancer, which remains one of the few malignancies where ICIs exhibit modest efficacy as either monotherapy or combination therapy. In this review, we summarize completed and ongoing clinical trials of PD-1/PD-L1 blockade in ovarian cancer, categorize the underlying mechanisms of resistance emergence, and introduce candidate approaches to rewire the tumor microenvironment (TME) to potentiate anti-PD-1/PD-L1 antibodies. Teaser: The intrinsic resistance of ovarian cancer to PD-1/PD-L1 blockade could be overcome by advanced understanding of underlying mechanisms and discoveries of new actionable targets for combinatory treatment.

Efficient complement-mediated clearance of immunosuppressed T cells by macrophages

Cancer is one of the leading causes of death worldwide. Treatment outcome is largely dictated by the tumor type, disease stage, and treatment success rates, but also by the variation among patients in endogenous anti-tumor responses. Studies indicate that the presence of neutrophils in the tumor microenvironment is associated with a worse patient outcome due to their ability to suppress local anti-tumor T cell activity. Our previous studies investigated the mechanisms by which neutrophils suppress and damage T cells to become smaller in size (small T cells), debilitating their effector activities. Several studies indicate a role for tumor-associated macrophages in scavenging damaged or dead cells. We hypothesized that the observed lack of small T cells in the TME by confocal microscopy is due to immediate uptake by macrophages. In this study, we confirmed that indeed only the smaller, damaged T cells are taken up by macrophages, once serum-opsonized. Damaged T cells opsonized with complement factor C3 fragments were phagocytosed by macrophages, resulting in almost instantaneous and highly efficient uptake of these small T cells. Inhibition of the complement receptors CR1, CR3 and CR4 expressed by macrophages completely blocked phagocytosis. By contrast, actively proliferating T cells (large T cells) were neither impaired in neutrophil-MDSC activity nor opsonized for phagocytosis by macrophages. Rapid removal of damaged T cells suggests a role of complement and macrophages within the tumor microenvironment to clear suppressed T cells in cancer patients.

Myeloid-derived suppressor cells: key immunosuppressive regulators and therapeutic targets in hematological malignancies

The immunosuppressive tumor microenvironment (TME) supports the development of tumors and limits tumor immunotherapy, including hematological malignancies. Hematological malignancies remain a major public health issue with high morbidity and mortality worldwide. As an important component of immunosuppressive regulators, the phenotypic characteristics and prognostic value of myeloid-derived suppressor cells (MDSCs) have received much attention. A variety of MDSC-targeting therapeutic approaches have produced encouraging outcomes. However, the use of various MDSC-targeted treatment strategies in hematologic malignancies is still difficult due to the heterogeneity of hematologic malignancies and the complexity of the immune system. In this review, we summarize the biological functions of MDSCs and further provide a summary of the phenotypes and suppressive mechanisms of MDSC populations expanded in various types of hematological malignancy contexts. Moreover, we discussed the clinical correlation between MDSCs and the diagnosis of malignant hematological disease, as well as the drugs targeting MDSCs, and focused on summarizing the therapeutic strategies in combination with other immunotherapies, such as various immune checkpoint inhibitors (ICIs), that are under active investigation. We highlight the new direction of targeting MDSCs to improve the therapeutic efficacy of tumors.

Humanized MISTRG as a preclinical in vivo model to study human neutrophil-mediated immune processes

Introduction

MISTRG mice have been genetically modified to allow development of a human myeloid compartment from engrafted human CD34+ haemopoietic stem cells, making them particularly suited to study the human innate immune system in vivo. Here, we characterized the human neutrophil population in these mice to establish a model that can be used to study the biology and contribution in immune processes of these cells in vivo.

Methods and results

We could isolate human bone marrow neutrophils from humanized MISTRG mice and confirmed that all neutrophil maturation stages from promyelocytes (CD11b–CD16–) to end-stage segmented cells (CD11b+CD16+) were present. We documented that these cells possessed normal functional properties, including degranulation, reactive oxygen species production, adhesion, and antibody-dependent cellular cytotoxicity towards antibody-opsonized tumor cells ex vivo. The acquisition of functional capacities positively correlated with the maturation state of the cell. We found that human neutrophils were retained in the bone marrow of humanized MISTRG mice during steady state. However, the mature segmented CD11b+CD16+ human neutrophils were released from the bone marrow in response to two well-established neutrophil-mobilizing agents (i.e., G-CSF and/or CXCR4 antagonist Plerixafor). Moreover, the neutrophil population in the humanized MISTRG mice actively reacted to thioglycolate-induced peritonitis and could infiltrate implanted human tumors, as shown by flow cytometry and fluorescent microscopy.

Discussion

These results show that functional human neutrophils are generated and can be studied in vivo using the humanized MISTRG mice, providing a model to study the various functions of neutrophils in inflammation and in tumors.

Neutrophil interactions with T cells, platelets, endothelial cells, and of course tumor cells

Neutrophils sense microbes and host inflammatory mediators, and traffic to sites of infection where they direct a broad armamentarium of antimicrobial products against pathogens. Neutrophils are also activated by damage-associated molecular patterns (DAMPs), which are products of cellular injury that stimulate the innate immune system through pathways that are similar to those activated by microbes. Neutrophils and platelets become activated by injury, and cluster and cross-signal to each other with the cumulative effect of driving antimicrobial defense and hemostasis. In addition, neutrophil extracellular traps are extracellular chromatin and granular constituents that are generated in response to microbial and damage motifs and are pro-thrombotic and injurious. Although neutrophils can worsen tissue injury, neutrophils may also have a role in facilitating wound repair following injury. A central theme of this review relates to how critical functions of neutrophils that evolved to respond to infection and damage modulate the tumor microenvironment (TME) in ways that can promote or limit tumor progression. Neutrophils are reprogrammed by the TME, and, in turn, can cross-signal to tumor cells and reshape the immune landscape of tumors. Importantly, promising new therapeutic strategies have been developed to target neutrophil recruitment and function to make cancer immunotherapy more effective.

High-quality and robust protein quantification in large clinical/pharmaceutical cohorts with IonStar proteomics investigation

Robust, reliable quantification of large sample cohorts is often essential for meaningful clinical or pharmaceutical proteomics investigations, but it is technically challenging. When analyzing very large numbers of samples, isotope labeling approaches may suffer from substantial batch effects, and even with label-free methods, it becomes evident that low-abundance proteins are not reliably measured owing to unsufficient reproducibility for quantification. The MS1-based quantitative proteomics pipeline IonStar was designed to address these challenges. IonStar is a label-free approach that takes advantage of the high sensitivity/selectivity attainable by ultrahigh-resolution (UHR)-MS1 acquisition (e.g., 120-240k full width at half maximum at m/z = 200) which is now widely available on ultrahigh-field Orbitrap instruments. By selectively and accurately procuring quantitative features of peptides within precisely defined, very narrow m/z windows corresponding to the UHR-MS1 resolution, the method minimizes co-eluted interferences and substantially enhances signal-to-noise ratio of low-abundance species by decreasing noise level. This feature results in high sensitivity, selectivity, accuracy and precision for quantification of low-abundance proteins, as well as fewer missing data and fewer false positives. This protocol also emphasizes the importance of well-controlled, robust experimental procedures to achieve high-quality quantification across a large cohort. It includes a surfactant cocktail-aided sample preparation procedure that achieves high/reproducible protein/peptide recoveries among many samples, and a trapping nano-liquid chromatography-mass spectrometry strategy for sensitive and reproducible acquisition of UHR-MS1 peptide signal robustly across a large cohort. Data processing and quality evaluation are illustrated using an example dataset ( http://proteomecentral.proteomexchange.org ), and example results from pharmaceutical project and one clinical project (patients with acute respiratory distress syndrome) are shown. The complete IonStar pipeline takes ~1-2 weeks for a sample cohort containing ~50-100 samples.

Alternative Complement Pathway Signature Determines Immunosuppression and Resistance to Immunotherapy Plus Tyrosine Kinase Inhibitor Combinations in Renal Cell Carcinoma

BACKGROUND

Latest guidelines recommended immunotherapy (IO) plus tyrosine kinase inhibitor (TKI) combination as standard first-line therapy in renal cell carcinoma (RCC), with no predictive biomarker being applied. Complement system shapes tumor microenvironment, which may influence TKI+IO benefit.

METHODS

Two cohorts from our institute and 2 external cohorts were enrolled. RNA-sequencing was performed for each sample, and alternative complement pathway signature (ACPS) was defined by single sample gene set enrichment analysis. Immune infiltration and function were assessed by immunohistochemistry and flow cytometry.

RESULTS

Under TKI+IO therapy, ACPS was elevated in non-responders (P<0.01), and high-ACPS predicted lower response rate and shorter progression-free survival (P=0.040). Moreover, TKI+IO, rather than TKI monotherapy, may benefit patients of low-ACPS combined with SETD2-wild type (HR=0.55, P<0.001). In RCC, ACPS was associated with increased tumor-infiltrating T cells (Spearman's ρ=0.50, P=0.001). However, in high-ACPS samples, CD8+ T cells revealed an exhausted phenotype with decreased GZMB (P<0.001) and increased PD1 (P=0.008) expression. Elevated PD1 expression in high-ACPS samples was confirmed by immunohistochemistry (P=0.046). Besides, macrophage infiltration was increased in high-ACPS samples (P=0.045), along with suppressive cytokines.

CONCLUSIONS

Under TKI+IO, high-ACPS was linked to immunosuppression and treatment resistance. ACPS might be used as a biomarker for better treatment strategy between TKI+IO or TKI monotherapy.

Establishing a signature based on immunogenic cell death-related gene pairs to predict immunotherapy and survival outcomes of patients with hepatocellular carcinoma

Immunogenic cell death (ICD) is a type of regulated cell death (RCD) triggered by various stresses that are involved in activating the immune system against cancer in immunocompetent hosts. However, no previous study has investigated the regulation of ICD-related gene pairs involved in hepatocellular carcinoma (HCC). A prognostic signature composed of 8 ICD-related gene pairs was generated that was capable of reliably separating patients with HCC into low- and high-risk subgroups with differing overall survival rates. Significant correlations were observed between risk score and surgical procedure, vascular tumor cell type, recurrence status, tumor status, and stages. The risk score was confirmed to be an independent prognostic factor for HCC and subsequently was employed to construct a prognostic nomogram. Low-risk patients were characterized by higher levels of immune cell infiltration, lower stromal and immune scores, higher tumor purity, higher expression of most immune checkpoints, and higher tumor mutational burden (TMB), revealing different levels of immunological functional pathways between different risk HCC patient cohorts. Furthermore, immunophenoscore (IPS) and Tumor Immune Dysfunction and Exclusion (TIDE) scores demonstrated that patients in the low-risk group are more likely to be sensitive to immunotherapy. In conclusion, the signature conducted by ICD-related gene pairs is a promising biomarker for the prediction of HCC patient outcomes and immunotherapeutic responses.

N1 versus N2 and PMN-MDSC: A critical appraisal of current concepts on tumor-associated neutrophils and new directions for human oncology

Research on tumor-associated neutrophils (TAN) currently surges because of the well-documented strong clinical relevance of tumor-infiltrating neutrophils. This relevance is illustrated by strong correlations between high frequencies of intratumoral neutrophils and poor outcome in the majority of human cancers. Recent high-dimensional analysis of murine neutrophils provides evidence for unexpected plasticity of neutrophils in murine models of cancer and other inflammatory non-malignant diseases. New analysis tools enable deeper insight into the process of neutrophil differentiation and maturation. These technological and scientific developments led to the description of an ever-increasing number of distinct transcriptional states and associated phenotypes in murine models of disease and more recently also in humans. At present, functional validation of these different transcriptional states and potential phenotypes in cancer is lacking. Current functional concepts on neutrophils in cancer rely mainly on the myeloid-derived suppressor cell (MDSC) concept and the dichotomous and simple N1-N2 paradigm. In this manuscript, we review the historic development of those concepts, critically evaluate these concepts against the background of our own work and provide suggestions for a refinement of current concepts in order to facilitate the transition of TAN research from experimental insight to clinical translation.

Suppression of T-Cell Proliferation by Normal Density Granulocytes Led to CD183 Downregulation and Cytokine Inhibition in T-Cells

Normal density granulocytes (NDGs) can suppress T-cell responses in a similar way as myeloid-derived suppressor cells (MDSCs). In this study, we tested the hypothesis that NDGs from healthy donors preferentially inhibit T helper 1 (Th1) cells and investigated the myeloid-derived suppressive effect in different T-cell populations. We found that NDG-induced suppression of T-cell proliferation was contact dependent, mediated by integrin CD11b, and dependent on NDG-production of reactive oxygen species (ROS). The suppression was rapid and occurred within the first few hours of coculture. The suppression did not influence the CD8+/CD4+ ratio indicating an equal sensitivity in these populations. We further analyzed the CD4+ T helper subsets and found that NDGs induced a loss of Th1 surface marker, CD183, that was unrelated to ligand-binding to CD183. In addition, we analyzed the Th1, Th2, and Th17 cytokine production and found that all cytokine groups were suppressed when T-cells were incubated with NDGs. We therefore concluded that NDGs do not preferentially suppress Th1-cells. Instead, NDGs generally suppress Th cells and cytotoxic T-cells but specifically downregulate the Th1 marker CD183.

Genome-wide profiling of retroviral DNA integration and its effect on clinical pre-infusion CAR T-cell products

Background

Clinical CAR T-cell therapy using integrating vector systems represents a promising approach for the treatment of hematological malignancies. Lentiviral and γ-retroviral vectors are the most commonly used vectors in the manufacturing process. However, the integration pattern of these viral vectors and subsequent effect on CAR T-cell products is still unclear.

Methods

We used a modified viral integration sites analysis (VISA) pipeline to evaluate viral integration events around the whole genome in pre-infusion CAR T-cell products. We compared the differences of integration pattern between lentiviral and γ-retroviral products. We also explored whether the integration sites correlated with clinical outcomes.

Results

We found that γ-retroviral vectors were more likely to insert than lentiviral vectors into promoter, untranslated, and exon regions, while lentiviral vector integration sites were more likely to occur in intron and intergenic regions. Some integration events affected gene expression at the transcriptional and post-transcriptional level. Moreover, γ-retroviral vectors showed a stronger impact on the host transcriptome. Analysis of individuals with different clinical outcomes revealed genes with differential enrichment of integration events. These genes may affect biological functions by interrupting amino acid sequences and generating abnormal proteins, instead of by affecting mRNA expression. These results suggest that vector integration is associated with CAR T-cell efficacy and clinical responses.

Conclusion

We found differences in integration patterns, insertion hotspots and effects on gene expression vary between lentiviral and γ-retroviral vectors used in CAR T-cell products and established a foundation upon which we can conduct further analyses.

VSSP abrogates murine ovarian tumor-associated myeloid cell-driven immune suppression and induces M1 polarization in tumor-associated macrophages from ovarian cancer patients

The ovarian tumor microenvironment (TME) is characterized by the accumulation of immunosuppressive tumor-associated macrophages (TAMs) and granulocytic cells. Very small size particles (VSSP), comprised of the ganglioside NAcGM3 and Neisseria meningitidis derived outer membrane vesicles, is being developed as a nanoparticulated modulator of innate immunity. Prior studies have shown that VSSP enhanced antigen-specific cytotoxic T cell responses and reduced the suppressive phenotype of splenic granulocytic cells in tumor-bearing mice. Here, we hypothesized that intraperitoneal VSSP would modify myeloid cell accumulation and phenotypes in the ovarian TME and abrogate suppressor function of TAMs and tumor-associated granulocytic cells. In the ID8 syngeneic model of epithelial ovarian cancer, VSSP reduced peritoneal TAMs and induced M1-like polarization in TAMs. In addition, VSSP stimulated peritoneal inflammation characterized by increased granulocytes and monocytes, including inflammatory monocytic cells. VSSP treatment resulted in peritoneal TAMs and granulocytic cells being less suppressive of ex vivo stimulated CD8+ T cell responses. VSSP alone and combined with anti-PD-1 modestly but significantly prolonged survival in tumor-bearing mice. In addition, ex vivo treatment with VSSP induced M1-like polarization in TAMs from patients with metastatic ovarian cancer and variably abrogated their suppressor phenotype. VSSP treatment also partially abrogated the induction of suppressor function in healthy donor neutrophils exposed to ascites supernatants from patients with ovarian cancer. Together, these results point to VSSP reprogramming myeloid responses resulting in abrogation of suppressive pathways and raise the potential for administration of VSSP into the TME to enhance anti-tumor immunity.

New Perspectives on Myeloid-Derived Suppressor Cells and Their Emerging Role in Haematology

Myeloid-derived suppressor cells (MDSCs) are immature cells of myeloid origin that have gained researchers’ attention, as they constitute promising biomarkers and targets for novel therapeutic strategies (i.e., blockage of development, differentiation, depletion, and deactivation) in several conditions, including neoplastic, autoimmune, infective, and inflammatory diseases, as well as pregnancy, obesity, and graft rejection. They are characterised in humans by the typical immunophenotype of CD11b⁺CD33⁺HLA-DR^–/low and immune-modulating properties leading to decreased T-cell proliferation, induction of T-regulatory cells (T-regs), hindering of natural killer (NK) cell functionality, and macrophage M2-polarisation. The research in the field is challenging, as there are still difficulties in defining cell-surface markers and gating strategies that uniquely identify the different populations of MDSCs, and the currently available functional assays are highly demanding. There is evidence that MDSCs display altered frequency and/or functionality and could be targeted in immune-mediated and malignant haematologic diseases, although there is a large variability of techniques and results between different laboratories. This review presents the current literature concerning MDSCs in a clinical point of view in an attempt to trigger future investigation by serving as a guide to the clinical haematologist in order to apply them in the context of precision medicine as well as the researcher in the field of experimental haematology.

The complement system as a regulator of tumor-promoting activities mediated by myeloid-derived suppressor cells

Tumor progression relies on the interaction between tumor cells and their surrounding tumor microenvironment (TME), which also influences therapeutic responses. The complement system, an essential part of innate immunity, has been traditionally considered an effector arm against tumors. However, established tumors co-opt complement-mediated immune responses in the TME to support chronic inflammation, activate cancer-related signaling pathways and hamper antitumor immune responses. In this context, myeloid-derived suppressor cells (MDSCs), a heterogeneous population of myeloid progenitors with immunosuppressive functions, are recognized as major mediators of tumor-associated complement activities. This review focuses on the impact of complement activation within the TME, with a special emphasis on MDSC functions and the involvement of the C5a/C5aR1 axis. We also discuss the translation of these findings into therapeutic advances based on complement inhibition.

Intracellular Lipid Accumulation Drives the Differentiation of Decidual Polymorphonuclear Myeloid-Derived Suppressor Cells via Arachidonic Acid Metabolism

Decidual polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) are essential to immune tolerance during pregnancy. A reduction in the number of these cells is associated with unexplained recurrent pregnancy loss (URPL). In our previous study, we reported that PMN-MDSCs are a group of mature neutrophils that are activated by the decidua microenvironment. In the present study, we show that the decidua microenvironment induces substantial lipid accumulation in neutrophils during their differentiation to PMN-MDSCs. Lower levels of lipid accumulation are detected in PMN-MDSCs from URPL patients, and the amount of lipid in the PMN-MDSCs is positively correlated with the proportion of PMN-MDSCs. Next, we demonstrate that decidua-derived IL6 with the presence of arachidonic acid upregulates fatty acid-binding protein 5 (FABP5) via the phosphorylation of signal transducer and activator of transcription 3 (STAT3). Fy -60ABP5 then continuously stimulates intracellular lipid accumulation. Increased intracellular lipid accumulation mediates arachidonic acid metabolism, a pathway that is significantly activated by the induction of the decidua microenvironment, to stimulate the synthesis of prostaglandin E2 (PGE2) and finally induce the differentiation of PMN-MDSCs. To summarize, decidua-derived IL6 facilitates the differentiation of PMN-MDSCs from neutrophils via the pSTAT3/FABP5/PGE2 pathway. Defects in the process may result in impaired differentiation and dysfunction of PMN-MDSCs in URPL. These findings enhance our understanding of the physiological mechanisms of immune tolerance in pregnancy and provide therapeutic options for URPL.

Differential Functional Responses of Neutrophil Subsets in Severe COVID-19 Patients

Neutrophils play a significant role in determining disease severity following SARS-CoV-2 infection. Gene and protein expression defines several neutrophil clusters in COVID-19, including the emergence of low density neutrophils (LDN) that are associated with severe disease. The functional capabilities of these neutrophil clusters and correlation with gene and protein expression are unknown. To define host defense and immunosuppressive functions of normal density neutrophils (NDN) and LDN from COVID-19 patients, we recruited 64 patients with severe COVID-19 and 26 healthy donors (HD). Phagocytosis, respiratory burst activity, degranulation, neutrophil extracellular trap (NET) formation, and T-cell suppression in those neutrophil subsets were measured. NDN from severe/critical COVID-19 patients showed evidence of priming with enhanced phagocytosis, respiratory burst activity, and degranulation of secretory vesicles and gelatinase and specific granules, while NET formation was similar to HD NDN. COVID LDN response was impaired except for enhanced NET formation. A subset of COVID LDN with intermediate CD16 expression (CD16^Int LDN) promoted T cell proliferation to a level similar to HD NDN, while COVID NDN and the CD16^Hi LDN failed to stimulate T-cell activation. All 3 COVID-19 neutrophil populations suppressed stimulation of IFN-γ production, compared to HD NDN. We conclude that NDN and LDN from COVID-19 patients possess complementary functional capabilities that may act cooperatively to determine disease severity. We predict that global neutrophil responses that induce COVID-19 ARDS will vary depending on the proportion of neutrophil subsets.

Influence of Malignant Pleural Fluid from Lung Adenocarcinoma Patients on Neutrophil Response

Simple Summary

This study provides novel information about the role of neutrophils in malignant pleural effusion (MPE) and hallmarks their clinical relevance. Since these cells have emerged as important regulators of cancer, we characterized their phenotype and functions in MPE microenvironment. We found that neutrophil-derived products (degranulation molecules and neutrophil extracellular traps (NETs)) were increased in MPE. In addition, NETs were associated with a worse outcome in lung adenocarcinoma patients with MPE.

Abstract

Malignant pleural effusion (MPE) is a common severe complication of advanced lung adenocarcinoma (LAC). Neutrophils, an essential component of tumor infiltrates, contribute to tumor progression and their counts in MPE have been associated with worse outcome in LAC. This study aimed to evaluate phenotypical and functional changes of neutrophils induced by MPE to determine the influence of MPE immunomodulatory factors in neutrophil response and to find a possible association between neutrophil functions and clinical outcomes. Pleural fluid samples were collected from 47 LAC and 25 heart failure (HF) patients. We measured neutrophil degranulation products by ELISA, oxidative burst capacity and apoptosis by flow cytometry, and NETosis by fluorescence. The concentration of degranulation products was higher in MPE-LAC than in PE-HF. Functionally, neutrophils cultured with MPE-LAC had enhanced survival and neutrophil extracellular trap (NET) formation but had reduced oxidative burst capacity. In MPE, NETosis was positively associated with MMP-9, P-selectin, and sPD-L1 and clinically related to a worse outcome. This is the first study associating NETs with a worse outcome in MPE. Neutrophils likely contribute to tumor progression through the release of NETs, suggesting that they are a potential therapeutic target in LAC.

Endoplasmic Reticulum Stress of Oral Squamous Cell Carcinoma Induces Immunosuppression of Neutrophils

The endoplasmic reticulum (ER) stress of cancer cells not only determined cancer cell fate but also indirectly triggered proinflammatory or immunosuppressive responses of macrophages. In addition, ER stressed neutrophils were known to acquire immunosuppressive activity with surface expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1). Since the importance of tumor ER stress and immunosuppressive neutrophils has been emphasized in head and neck cancers, we hypothesized that the ER stress of oral squamous cell carcinoma (OSCC) could transform neutrophils into LOX-1 expressing immunosuppressive phenotype. Two human OSCC cell lines, SCC25 and OML1, were treated with either vehicle or thapsigargin (THG), an ER stress inducer. These tumor conditioned media (TCM) were collected accordingly. Then human peripheral blood neutrophils from healthy donors were cultured in these TCM. The results showed that neutrophils cultured in THG-treated TCM had higher expression of LOX-1 compared with those cultured in vehicle-treated TCM. Moreover, by interleukin-2/anti-CD3/anti-CD28 activated autologous T cell proliferation assay, neutrophils conditioned by THG-treated TCM were shown to inhibit T cell proliferation more significantly than those conditioned by vehicle-treated TCM. These novel findings indicated that the ER stress of OSCC could be transmitted to neutrophils which in turn expressed LOX-1 and obtained immunosuppressive ability. Our findings further supported the existence of "transmissible" ER stress between tumor cells and neutrophils.

Epigenetic and transcriptional regulation of innate immunity in cancer

Innate immune cells participate in the detection of tumor cells via complex signaling pathways mediated by pattern-recognition receptors, such as Toll-like receptors (TLR) and NOD-like receptors (NLR). These pathways are finely tuned via multiple mechanisms, including epigenetic regulation. It is well established that hematopoietic progenitors generate innate immune cells that can regulate cancer cell behavior, and the disruption of normal hematopoiesis in pathologic states may lead to altered immunity and the development of cancer. In this review, we discuss the epigenetic and transcriptional mechanisms that underlie the initiation and amplification of innate immune signaling in cancer. We also discuss new targeting possibilities for cancer control that exploit innate immune cells and signaling molecules, potentially heralding the next generation of immunotherapy.

Neutrophils Lose the Capacity to Suppress T Cell Proliferation Upon Migration Towards Inflamed Joints in Juvenile Idiopathic Arthritis

Neutrophils are highly abundant in synovial fluid of rheumatic inflamed joints. In oligoarticular juvenile idiopathic arthritis (JIA), synovial fluid neutrophils have impaired effector functions and altered phenotype. We hypothesized that these alterations might impact the immunoregulatory interplay between neutrophils and T cells. In this study we analyzed the suppressive effect of neutrophils, isolated from blood and synovial fluid of oligoarticular JIA patients, on CD4⁺ T cells activated by CD3/CD28 stimulation. JIA blood neutrophils suppressed T cell proliferation but synovial fluid neutrophils from several patients did not. The loss of T cell suppression was replicated in an in vitro transmigration assay, where healthy control neutrophils migrated into synovial fluid through transwell inserts with endothelial cells and synoviocytes. Non-migrated neutrophils suppressed proliferation of activated CD4⁺ T cells, but migrated neutrophils had no suppressive effect. Neutrophil suppression of T cells was partly dependent on reactive oxygen species (ROS), demonstrated by impaired suppression in presence of catalase. Migrated neutrophils had reduced ROS production compared to non-migrated neutrophils. A proteomic analysis of transwell-migrated neutrophils identified alterations in proteins related to neutrophil ROS production and degranulation, and biological processes involving protein transport, cell-cell contact and inflammation. In conclusion, neutrophils in synovial fluid of children with JIA have impaired capacity to suppress activated T cells, which may be due to reduced oxidative burst and alterations in proteins related to cell-cell contact and inflammation. The lack of T cell suppression by neutrophils in synovial fluid may contribute to local inflammation and autoimmune reactions in the JIA joint.

Lin28B-high breast cancer cells promote immune suppression in the lung pre-metastatic niche via exosomes and support cancer progression

The formation of pre-metastatic niche is a key step in the metastatic burden. The pluripotent factor Lin28B is frequently expressed in breast tumors and is particularly upregulated in the triple negative breast cancer subtype. Here, we demonstrate that Lin28B promotes lung metastasis of breast cancer by building an immune-suppressive pre-metastatic niche. Lin28B enables neutrophil recruitment and N2 conversion. The N2 neutrophils are then essential for immune suppression in pre-metastatic lung by PD-L2 up-regulation and a dysregulated cytokine milieu. We also identify that breast cancer-released exosomes with low let-7s are a prerequisite for Lin28B-induced immune suppression. Moreover, Lin28B-induced breast cancer stem cells are the main sources of low-let-7s exosomes. Clinical data further verify that high Lin28B and low let-7s in tumors are both indicators for poor prognosis and lung metastasis in breast cancer patients. Together, these data reveal a mechanism by which Lin28B directs the formation of an immune-suppressive pre-metastatic niche.

The establishment of a pre-metastatic niche is a key step preceding metastasis formation. Here the authors show that tumor-intrinsic Lin28B, a RNA-binding protein, has an essential role in the formation of an immune-suppressive pre-metastatic niche, promoting lung metastasis of breast cancer.

LYVE1+ macrophages of murine peritoneal mesothelium promote omentum-independent ovarian tumor growth

Two resident macrophage subsets reside in peritoneal fluid. Macrophages also reside within mesothelial membranes lining the peritoneal cavity, but they remain poorly characterized. Here, we identified two macrophage populations (LYVE1hi MHC IIlo-hi CX3CR1gfplo/- and LYVE1lo/- MHC IIhi CX3CR1gfphi subsets) in the mesenteric and parietal mesothelial linings of the peritoneum. These macrophages resembled LYVE1+ macrophages within surface membranes of numerous organs. Fate-mapping approaches and analysis of newborn mice showed that LYVE1hi macrophages predominantly originated from embryonic-derived progenitors and were controlled by CSF1 made by Wt1+ stromal cells. Their gene expression profile closely overlapped with ovarian tumor-associated macrophages previously described in the omentum. Indeed, syngeneic epithelial ovarian tumor growth was strongly reduced following in vivo ablation of LYVE1hi macrophages, including in mice that received omentectomy to dissociate the role from omental macrophages. These data reveal that the peritoneal compartment contains at least four resident macrophage populations and that LYVE1hi mesothelial macrophages drive tumor growth independently of the omentum.

Prognostic significance of neutrophil-to-lymphocyte ratio for long-term outcomes in patients with poorly differentiated thyroid cancer

Poorly differentiated thyroid cancer (PDTC) is a distinct but rare type of thyroid cancer with intermediate biological behavior between differentiated and anaplastic thyroid cancers. PDTC was first defined in 2005 in Japan, but the diagnostic criteria changed in 2015, requiring the tumor to have more than 50% of poorly differentiated components for diagnosis. Because only six years have passed since the PDTC definition change, prognostic factors for long-term survival who meet the latest criteria have not been determined. Neutrophil-to-lymphocyte ratio (NLR) is a prognostic marker in various solid malignancies. However, its impact on PDTC remains unclear. This study aimed to evaluate the significance of NLR as a prognostic factor for patients with PDTC diagnosed based on the latest criteria. In total, 28 PDTC cases (4.4%) of 637 thyroid cancer patients who underwent surgery between 2002 and 2012 were retrospectively analyzed. The median follow-up period was 120 months (range, 7-216 months). Of the 13 deaths (46.4%), 9 patients (32.1%) died from PDTC. The median preoperative NLR was 2.7 (0.67-8.62), and the NLR cut-off value determined by the receiver operating characteristic curve was 2.88. Patients with a high NLR (>2.88) showed significantly worse disease-specific survival (hazard ratio [HR] 4.67, p = 0.036) and overall survival (HR 4.94, p = 0.007) than those with a low NLR (≤2.88). Multivariate analysis revealed that a high NLR independently predicted a worse prognosis (HR 6.06, p = 0.0087). In conclusion, NLR is a useful prognostic marker for patients with PDTC.

Ovarian cancer modulates the immunosuppressive function of CD11b+Gr1+ myeloid cells via glutamine metabolism

OBJECTIVE

Immature CD11b + Gr1+ myeloid cells that acquire immunosuppressive capability, also known as myeloid-derived suppressor cells (MDSCs), are a heterogeneous population of cells that regulate immune responses. Our study's objective was to elucidate the role of ovarian cancer microenvironment in regulating the immunosuppressive function of CD11b+Gr1+ myeloid cells.

METHODS

All studies were performed using the intraperitoneal ID8 syngeneic epithelial ovarian cancer mouse model. Myeloid cell depletion and immunotherapy were carried out using anti-Gr1 mAb, gemcitabine treatments, and/or anti-PD1 mAb. The treatment effect was assessed by a survival curve, in situ luciferase-guided imaging, and histopathologic evaluation. Adoptive transfer assays were carried out between congenic CD45.2 and CD45.1 mice. Immune surface and intracellular markers were assessed by flow cytometry. ELISA, western blot, and RT-PCR techniques were employed to assess the protein and RNA expression of various markers. Bone marrow-derived myeloid cells were used for ex-vivo studies.

RESULTS

The depletion of Gr1+ immunosuppressive myeloid cells alone and in combination with anti-PD1 immunotherapy inhibited ovarian cancer growth. In addition to the adoptive transfer studies, these findings validate the role of immunosuppressive CD11b+Gr1+ myeloid cells in promoting ovarian cancer. Mechanistic investigations showed that ID8 tumor cells and their microenvironments produced recruitment and regulatory factors for immunosuppressive CD11b+Gr1+ myeloid cells. CD11b+Gr1+ myeloid cells primed by ID8 tumors showed increased immunosuppressive marker expression and acquired an energetic metabolic phenotype promoted primarily by increased oxidative phosphorylation fueled by glutamine. Inhibiting the glutamine metabolic pathway reduced the increased oxidative phosphorylation and decreased immunosuppressive markers' expression and function. Dihydrolipoamide succinyl transferase (DLST), a subunit of α-KGDC in the TCA cycle, was found to be the most significantly elevated gene in tumor-primed myeloid cells. The inhibition of DLST reduced oxidative phosphorylation, immunosuppressive marker expression and function in myeloid cells.

CONCLUSION

Our study shows that the ovarian cancer microenvironment can regulate the metabolism and function of immunosuppressive CD11b + Gr1+ myeloid cells and modulate its immune microenvironment. Targeting glutamine metabolism via DLST in immunosuppressive myeloid cells decreased their activity, leading to a reduction in the immunosuppressive tumor microenvironment. Thus, targeting glutamine metabolism has the potential to enhance the success of immunotherapy in ovarian cancer.

Identification of an Immune-Related Prognostic Gene CLEC5A Based on Immune Microenvironment and Risk Modeling of Ovarian Cancer

Objective: To understand the immune characteristics of the ovarian cancer (OC) microenvironment and explore the differences of immune-related molecules and cells to establish an effective risk model and identify the molecules that significantly affected the immune response of OC, to help guide the diagnosis. Methods: First, we calculate the TMEscore which reflects the immune microenvironment, and then analyze the molecular differences between patients with different immune characteristics, and determine the prognostic genes. Then, the risk model was established by least absolute shrinkage and selection operator (LASSO) analysis and combined with clinical data into a nomogram for diagnosis and prediction. Subsequently, the potential gene CLEC5A influencing the immune response of OC was identified from the prognostic genes by integrative immune-stromal analysis. The genomic alteration was explored based on copy number variant (CNV) and somatic mutation data. Results: TMEscore was a prognostic indicator of OC. The prognosis of patients with high TMEscore was better. The risk model based on immune characteristics was a reliable index to predict the prognosis of patients, and the nomogram could comprehensively evaluate the prognosis of patients. Besides, CLEC5A was closely related to the abundance of immune cells, immune response, and the expression of immune checkpoints in the OC microenvironment. OC cells with high expression of CLEC5A increased the polarization of M2 macrophages. CLEC5A expression was significantly associated with TTN and CDK12 mutations and affected the copy number of tumor progression and immune-related genes. Conclusion: The study of immune characteristics in the OC microenvironment and the risk model can reveal the factors affecting the prognosis and guide the clinical hierarchical treatment. CLEC5A can be used as a potential key gene affecting the immune microenvironment remodeling of OC, which provides a new perspective for improving the effect of OC immunotherapy.

Microdissection of the Bulk Transcriptome at Single-Cell Resolution Reveals Clinical Significance and Myeloid Cells Heterogeneity in Lung Adenocarcinoma

Background

Tumor infiltrating myeloid (TIM) cells constitute a vital element of the tumor microenvironment. The cell-type heterogeneity of TIM has yet to be fully investigated.

Methods

We used a time saving approach to generate a single-cell reference matrix, allowing quantification of cell-type proportions and cell-type-specific gene abundances in bulk RNA-seq data.

Results

Two distinct clusters, MSC1 and MSC2 (MSC subtype) were newly identified in lung adenocarcinoma (LUAD) patients, both significantly associated with overall survival and immune blockade therapy responses. Twenty myeloid cell types were detected. Thirteen of these had distinct enrichment patterns between MSC1 and MSC2. LAMP3+ dendritic cells, being a mature and transportable subtype of dendritic cell that may migrate to lymph nodes, were noted as associated with non-responsiveness to immunotargeted therapy. High infiltration level of IFIT3+ neutrophils was strongly related to the response to immune-targeted therapy and was seen to activate CD8+ T cells, partly through inflammasome activation. The infiltration levels of TIMP1+ macrophages and S100A8+ neutrophils were both significantly associated with poor prognosis. TIMP1+ macrophages were noted to recruit S100A8+ neutrophils via the CXCL5-CXCR2 axes and promote LUAD progression.

Conclusion

Altogether, we performed virtual microdissection of the bulk transcriptome at single-cell resolution and provided a promising TIM infiltration landscape that may shed new light on the development of immune therapy.

Identification of seven novel ferroptosis-related long non-coding RNA signatures as a diagnostic biomarker for acute myeloid leukemia

Background

Ferroptosis is a newly discovered type of programmed cell death that participates in the biological processes of various cancers. However, the mechanism by which ferroptosis modulates acute myeloid leukemia (AML) remains unclear. This study aimed to investigate the role of ferroptosis-related long non-coding RNAs (lncRNAs) in AML and establish a corresponding prognostic model.

Methods

RNA-sequencing data and clinicopathological characteristics were obtained from The Cancer Genome Atlas database, and ferroptosis-related genes were obtained from the FerrDb database. The “limma” R package, Cox regression, and the least absolute shrinkage and selection operator were used to determine the ferroptosis-related lncRNA signature with the lowest Akaike information criteria (AIC). The risk score of ferroptosis-related lncRNAs was calculated and patients with AML were divided into high- and low-risk groups based on the median risk score. The Kaplan–Meier curve and Cox regression were used to evaluate the prognostic value of the risk score. Finally, gene set enrichment analysis (GSEA) and single-sample gene set enrichment analysis (ssGSEA) were performed to explore the biological functions of the ferroptosis-related lncRNAs.

Results

Seven ferroptosis-related lncRNA signatures were identified in the training group, and Kaplan–Meier and Cox regression analyses confirmed that risk scores were independent prognostic predictors of AML in both the training and validation groups (All P < 0.05). In addition, the area under the curve (AUC) analysis confirmed that the signatures had a good predictive ability for the prognosis of AML. GSEA and ssGSEA showed that the seven ferroptosis-related lncRNAs were related to glutathione metabolism and tumor immunity.

Conclusions

In this study, seven novel ferroptosis-related lncRNA signatures (AP001266.2, AC133961.1, AF064858.3, AC007383.2, AC008906.1, AC026771.1, and KIF26B-AS1) were established. These signatures were shown to accurately predict the prognosis of AML, which would provide new insights into strategies for the development of new AML therapies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01085-9.

Role of Complement in Regulating Inflammation Processes in Renal and Prostate Cancers

For decades, the complement system, the central pillar of innate immune response, was recognized as a protective mechanism against cancer cells and the manipulation of complement effector functions in cancer setting offered a great opportunity to improve monoclonal antibody-based cancer immunotherapies. Similarly, cellular senescence, the process of cell cycle arrest that allow DNA and tissue repair has been traditionally thought to be able to suppress tumor progression. However, in recent years, extensive research has identified the complement system and cellular senescence as two main inducers of tumour growth in the context of chronic, persistent inflammation named inflammaging. Here, we discuss the data describing the ambivalent role of senescence in cancer with a particular focus on tumors that are strongly dependent on complement activation and can be understood by a new, senescence-related point of view: prostate cancer and renal cell carcinoma.

Bone Marrow Neutrophils of Multiple Myeloma Patients Exhibit Myeloid-Derived Suppressor Cell Activity

Activated normal density granulocytes (NDGs) can suppress T-cell responses in a similar way as myeloid-derived suppressor cells (MDSCs). In this study, we tested the hypothesis that NDGs from blood and bone marrow of multiple myeloma (MM) patients have the ability to suppress T-cells, as MDSC. MM is an incurable plasma cell malignancy of the bone marrow. Like most malignancies, myeloma cells alter its microenvironment to promote tumor growth, including inhibition of the immune system. We found that MM NDG from the bone marrow suppressed proliferation of T-cells, in contrast to healthy donors. The inhibitory effect could not be explained by changed levels of mature or immature NDG in the bone marrow. Moreover, NDG isolated from the blood of both myeloma patients and healthy individuals could inhibit T-cell proliferation and IFN-γ production. On the contrary to previous studies, blood NDGs did not have to be preactivated to mediate suppressive effects. Instead, they became activated during coculture, indicating that contact with activated T-cells is important for their ability to regulate T-cells. The inhibitory effect was dependent on the production of reactive oxygen species and could be reverted by the addition of its inhibitor, catalase. Our findings suggest that blood NDGs from MM patients are suppressive, but no more than NDGs from healthy donors. However, only bone marrow NDG from MM patients exhibited MDSC function. This MDSC-like suppression mediated by bone marrow NDG could be important for the growth of malignant plasma cells in MM patients.

Neutrophil expansion defines an immunoinhibitory peripheral and intratumoral inflammatory milieu in resected non-small cell lung cancer: a descriptive analysis of a prospectively immunoprofiled cohort

Background

The biological underpinnings of the prognostic and predictive significance of a relative neutrophilia in patients with non-small lung cancer (NSCLC) are undefined. We sought to comprehensively examine the relationships between circulating and intratumoral neutrophil populations and features of the immune contexture in patients undergoing NSCLC resection.

Methods

Preoperative soluble cytokine and angiogenic factors; tumor multiplex immunofluorescence; RNA, whole exome, and T-cell receptor sequencing; and flow cytometry were analyzed for relationships with populations of circulating (from complete blood counts) and intratumoral neutrophils (transcriptional signatures) in a prospectively enrolled resected NSCLC cohort (n=66). In a historical cohort (n=1524), preoperative circulating neutrophil and lymphocyte counts were analyzed for associations with overall survival (OS).

Results

Circulating neutrophil populations were positively correlated with increased tumor burden, and surgical tumor resection was followed by a subsequent reduction in peripheral neutrophil counts. Expansion of the circulating neutrophil compartment was associated with increased levels of pro-granulopoietic (IL-1β, IL-17A, TNFα, IL-6) and T_H2-associated (IL-5, IL-13) cytokines. Tumors with high intratumoral neutrophil burden were marked by a blunted T-cell response characterized by reduced expression of cytotoxic T-cell genes (CD8A, CD8B, GZMA, GZMB), decreased CD3⁺CD8⁺ cell infiltration, and diminished expression of IFNγ-related genes. The associations between increased intratumoral neutrophil burden and reduced CD3⁺CD8⁺ infiltration persisted after adjustment for tumor size, histology, mutational burden, and PD-L1 expression. In 1524 patients, elevated preoperative circulating neutrophil count was independently associated with worse OS (main effect HR 1.82, 95% CI 1.24 to 2.68, p=0.002).

Conclusions

Our findings demonstrate that neutrophil expansion reflects protumorigenic and immunosuppressive processes that manifest as worse OS in patients undergoing NSCLC resection. These results justify further investigation of therapeutic strategies targeting neutrophil-associated immune evasion.