Neutrophil-lymphocyte ratio reflects tumour-infiltrating lymphocytes and tumour-associated macrophages and independently predicts poor outcome in breast cancers with neoadjuvant chemotherapy

AIMS

The neutrophil-lymphocyte ratio (NLR) is a systemic reflection of cancer-associated inflammation and a prognostic marker for breast cancer. For the local tumour microenvironment, tumour-infiltrating lymphocytes (TILs) and tumour-associated macrophages (TAMs) are also highly correlated with breast cancer survival. This study aimed to explore the relationship between the circulating and local immune microenvironment, and to further delineate the prognostic role of NLR in breast cancer patients receiving neoadjuvant chemotherapy (NAC).

METHODS

A cohort of breast cancer patients receiving NAC with subsequent surgery was retrieved. Clinical data were reviewed. Histological slides and CD8 immunohistochemistry from biopsy (pre-chemotherapy) and excision (postchemotherapy) specimens were assessed for TILs and TAMs.

RESULTS

A total of 146 patients were included. There was a significant positive correlation between pre- and postsurgery NLR at a cut-off of 2.6 (median pre-chemotherapy NLR) (P < 0.001). NLR pre-chemotherapy was associated positively with necrosis on biopsy (P = 0.027) and excision (P = 0.021) and TAMs on excision (P = 0.049). NLR 1 year postsurgery was associated with high tumour stage (P = 0.050) and low histological grade (P = 0.008). TIL count was lower in NLR-high cases at almost all time-points by histological assessment and CD8 immunostaining (P < 0.050). In multivariate analysis, postsurgery NLR is an independent predictor for overall survival [OS; hazard ratio (HR) = 9.524, P < 0.001], breast cancer-specific survival (BCSS) (HR = 10.059, P = 0.001) and disease-free survival (DFS; HR = 2.824, P = 0.016).

CONCLUSIONS

The association between NLR with tumour necrosis, TAMs and TILs illustrates an interaction between the circulating and local immune microenvironment. Late NLR is a strong indicator of outcome and may be useful for prognostication and disease monitoring.

Tumour-associated macrophage-derived DOCK7-enriched extracellular vesicles drive tumour metastasis in colorectal cancer via the RAC1/ABCA1 axis

BACKGROUND

Metastasis accounts for the majority of deaths among patients with colorectal cancer (CRC). Here, the regulatory role of tumour-associated macrophages (TAMs) in CRC metastasis was explored.

METHODS

Immunohistochemical (IHC) analysis of the TAM biomarker CD163 was conducted to evaluate TAM infiltration in CRC. Transwell assays and an ectopic liver metastasis model were established to evaluate the metastatic ability of tumour cells. RNA sequencing (RNA-seq) and liquid chromatography-mass spectrometry (LC-MS) were applied to identify the differentially expressed genes and proteins in CRC cells and in TAM-derived extracellular vesicles (EVs). Cholesterol content measurement, a membrane fluidity assay and filipin staining were performed to evaluate cholesterol efflux in CRC cells.

RESULTS

Our results showed that TAM infiltration is positively correlated with CRC metastasis. TAMs can facilitate the migration and invasion of MC-38 and CT-26 cells via EVs. According to the RNA-seq data, TAM-EVs increase cholesterol efflux and enhance membrane fluidity in CRC cells by regulating ABCA1 expression, thus affecting the motility of CRC cells. Mechanistically, DOCK7 packaged in TAM-EVs can activate RAC1 in CRC cells and subsequently upregulate ABCA1 expression by phosphorylating AKT and FOXO1. Moreover, IHC analysis of ABCA1 in patients with liver-metastatic CRC indicated that ABCA1 expression is significantly greater in metastatic liver nodules than in primary CRC tumours.

CONCLUSIONS

Overall, our findings suggest that DOCK7 delivered via TAM-EVs could regulate cholesterol metabolism in CRC cells and CRC cell metastasis through the RAC1/AKT/FOXO1/ABCA1 axis. DOCK7 could thus be a new therapeutic target for controlling CRC metastasis.

Blockade of V-domain immunoglobulin suppressor of T-cell activation reprograms tumour-associated macrophages and improves efficacy of PD-1 inhibitor in gastric cancer

BACKGROUND AND AIMS

In gastric cancer, the response rate of programmed cell death protein-1 (PD-1) inhibitor is far from satisfactory, indicating additional nonredundant pathways might hamper antitumour immunity. V-domain immunoglobulin suppressor of T-cell activation (VISTA) has been reported in several malignancies as a novel immune-checkpoint. Nevertheless, the role of VISTA in gastric cancer still remains obscure. Our purpose is to explore the clinical significance and potential mechanism of VISTA in affecting gastric cancer patients' survival and immunotherapeutic responsiveness.

METHODS

Our study recruited eight independent cohorts with a total of 1403 gastric cancer patients. Immunohistochemistry, multiplex immunofluorescence, flow cytometry or intracellular flow cytometry, quantitative polymerase chain reaction, western blotting, fluorescence-activated cell sorting, magnetic-activated cell sorting, smart-seq2, in vitro cell co-culture and ex vivo tumour inhibition assays were applied to investigate the clinical significance and potential mechanism of VISTA in gastric cancer.

RESULTS

VISTA was predominantly expressed on tumour-associated macrophages (TAMs), and indicated poor clinical outcomes and inferior immunotherapeutic responsiveness. VISTA+ TAMs showed a mixed phenotype. Co-culture of TAMs and CD8+ T cells indicated that VISTA+ TAMs attenuated effective function of CD8+ T cells. Blockade of VISTA reprogrammed TAMs to a proinflammatory phenotype, reactivated CD8+ T cells and promoted apoptosis of tumour cells. Moreover, blockade of VISTA could also enhance the efficacy of PD-1 inhibitor, suggesting that blockade of VISTA might synergise with PD-1 inhibitor in gastric cancer.

CONCLUSIONS

Our data revealed that VISTA was an immune-checkpoint associated with immunotherapeutic resistance. Blockade of VISTA reprogrammed TAMs, promoted T-cell-mediated antitumour immunity, and enhanced efficacy of PD-1 inhibitor, which might have implications in the treatment of gastric cancer.

The role of macrophages in gastric cancer

As one of the deadliest cancers of the gastrointestinal tract, there has been limited improvement in long-term survival rates for gastric cancer (GC) in recent decades. The poor prognosis is attributed to difficulties in early detection, minimal opportunity for radical resection and resistance to chemotherapy and radiation. Macrophages are among the most abundant infiltrating immune cells in the GC stroma. These cells engage in crosstalk with cancer cells, adipocytes and other stromal cells to regulate metabolic, inflammatory and immune status, generating an immunosuppressive tumour microenvironment (TME) and ultimately promoting tumour initiation and progression. In this review, we summarise recent advances in our understanding of the origin of macrophages and their types and polarisation in cancer and provide an overview of the role of macrophages in GC carcinogenesis and development and their interaction with the GC immune microenvironment and flora. In addition, we explore the role of macrophages in preclinical and clinical trials on drug resistance and in treatment of GC to assess their potential therapeutic value in this disease.

Tumor macrophage functional heterogeneity can inform the development of novel cancer therapies

Macrophages represent a key component of the tumor microenvironment (TME) and are largely associated with poor prognosis. Therapeutic targeting of macrophages has historically focused on inhibiting their recruitment or reprogramming their phenotype from a protumor (M2-like) to an antitumor (M1-like) one. Unfortunately, this approach has not provided clinical breakthroughs that have changed practice. Emerging studies utilizing single-cell RNA-sequencing (scRNA-seq) and spatial transcriptomics have improved our understanding of the ontogeny, phenotype, and functional plasticity of macrophages. Overlaying the wealth of current information regarding macrophage molecular subtypes and functions has also identified novel therapeutic vulnerabilities that might drive better control of tumor-associated macrophages (TAMs). Here, we discuss the functional profiling of macrophages and provide an update of novel macrophage-targeted therapies in development.

Prognostic Markers within the Tumour Microenvironment in Classical Hodgkin Lymphoma

Classical Hodgkin lymphoma (cHL) accounts for 0.4% of all new cancer cases globally. Despite high cure rates with standard treatment, approximately 15% of patients still experience relapsed or refractory (RR) disease, and many of these eventually die from lymphoma-related causes. Exciting new targeted agents such as anti-PD-1 agents and brentuximab vedotin have changed the therapeutic paradigm beyond chemotherapy and radiotherapy alone. Advances in understanding of the molecular biology are providing insights in the context of novel therapies. The signature histology of cHL requires the presence of scant malignant Hodgkin Reed-Sternberg cells (HRSCs) surrounded by a complex immune-rich tumour microenvironment (TME). The TME cellular composition strongly influences outcomes, yet knowledge of the precise characteristics of TME cells and their interactions with HRSCs is evolving. Novel high-throughput technologies and single-cell sequencing allow deeper analyses of the TME and mechanisms elicited by HRSCs to propagate growth and avoid immune response. In this review, we explore the evolution of knowledge on the prognostic role of immune cells within the TME and provide an up-to-date overview of emerging prognostic data on cHL from new technologies that are starting to unwind the complexity of the cHL TME and provide translational insights into how to improve therapy in the clinic.

Tumour-associated macrophages: versatile players in the tumour microenvironment

Tumour-Associated Macrophages (TAMs) are one of the pivotal components of the tumour microenvironment. Their roles in the cancer immunity are complicated, both pro-tumour and anti-cancer activities are reported, including not only angiogenesis, extracellular matrix remodeling, immunosuppression, drug resistance but also phagocytosis and tumour regression. Interestingly, TAMs are highly dynamic and versatile in solid tumours. They show anti-cancer or pro-tumour activities, and interplay between the tumour microenvironment and cancer stem cells and under specific conditions. In addition to the classic M1/M2 phenotypes, a number of novel dedifferentiation phenomena of TAMs are discovered due to the advanced single-cell technology, e.g., macrophage-myofibroblast transition (MMT) and macrophage-neuron transition (MNT). More importantly, emerging information demonstrated the potential of TAMs on cancer immunotherapy, suggesting by the therapeutic efficiency of the checkpoint inhibitors and chimeric antigen receptor engineered cells based on macrophages. Here, we summarized the latest discoveries of TAMs from basic and translational research and discussed their clinical relevance and therapeutic potential for solid cancers.

Targeting the Heterogeneous Tumour-Associated Macrophages in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a prevalent and aggressive cancer that comprises a complex tumour microenvironment (TME). Tumour-associated macrophages (TAMs) are one of the most abundant immune cells present in the TME, and play a key role both in the development and in the progression of HCC. Thus, TAM-based immunotherapy has been presented as a promising strategy to complement the currently available therapies for HCC treatment. Among the novel approaches focusing on TAMs, reprogramming their functional state has emerged as a promising option for targeting TAMs as an immunotherapy in combination with the currently available treatment options. Nevertheless, a further understanding of the immunobiology of TAMs is still required. This review synthesizes current insights into the heterogeneous nature of TAMs in HCC and describes the mechanisms behind their pro-tumoural polarization focusing the attention on their interaction with HCC cells. Furthermore, this review underscores the potential involvement of TAMs' reprogramming in HCC therapy and highlights the urgency of advancing our understanding of these cells within the dynamic landscape of HCC.

DACH1 regulates macrophage activation and tumour progression in hypopharyngeal squamous cell carcinoma

Dachshund family transcription factor 1 (DACH1) has been shown to exhibit a tumour-suppressive role in a number of human cancers. However, the role of DACH1 in hypopharyngeal squamous cell carcinoma (HPSCC) and its function in the tumour microenvironment (TME) are still not clear. Crosstalk between cancer cells and tumour-associated macrophages (TAMs) mediates tumour progression in HPSCC. The expression of DACH1, CD86 and CD163 was detected in 71 matched HPSCC-non-cancerous tissue pairs using quantitative real-time polymerase chain reaction and IHC analysis. Cell proliferation, migration and invasion were monitored by colony formation, Transwell and EdU incorporation assays. ChIP-qPCR and dual-luciferase reporter assays were applied to verify the targeting relationships between DACH1 and IGF-1. Stably transfected HPSCC cells were co-cultured with MΦ macrophages to assess macrophage polarization and secretory signals. DACH1 was decreased in HPSCC tissues and was indicative of a poor prognosis for HPSCC patients. Decreased DACH1 expression in HPSCC was associated with fewer CD86+ TAMs and more CD163+ TAMs. Knockdown of DACH1 inhibited the proliferation, migration and invasion of FaDu cells via Akt/NF-κB/MMP2/9 signalling. Additionally, DACH1 was found to directly bind to the promoter region of IGF-1 to downregulate the secretion of IGF-1, which inhibited TAMs polarization through the IGF-1R/JAK1/STAT3 axis. Furthermore, in nude mice, the effects of DACH1 inhibition on tumour progression and M2-like TAMs polarization were confirmed. These findings suggest that IGF-1 is a critical downstream effector of DACH1 that suppresses cell migration and invasion and inhibits TAMs polarization. DACH1 could be a therapeutic target and prognostic marker for HPSCC.

Irreversible repolarization of tumour-associated macrophages by low-Pi stress inhibits the progression of hepatocellular carcinoma

Numerous studies have shown the positive correlation between high levels of Pi and tumour progression. A critical goal of macrophage-based cancer therapeutics is to reduce anti-inflammatory macrophages (M2) and increase proinflammatory antitumour macrophages (M1). This study aimed to investigate the relationship between macrophage polarization and low-Pi stress. First, the spatial populations of M2 and M1 macrophages in 22 HCC patient specimens were quantified and correlated with the local Pi concentration. The levels of M2 and M1 macrophage markers expressed in the peritumour area were higher than the intratumour levels, and the expression of M2 markers was positively correlated with Pi concentration. Next, monocytes differentiated from THP-1 cells were polarized against different Pi concentrations to investigate the activation or silencing of the expression of p65, IκB-α and STAT3 as well as their phosphorylation. Results showed that low-Pi stress irreversibly repolarizes tumour-associated macrophages (TAMs) towards the M1 phenotype by silencing stat6 and activating p65. Moreover, HepG-2 and SMCC-7721 cells were cultured in conditioned medium to investigate the innate anticancer immune effects on tumour progression. Both cancer cell lines showed reduced proliferation, migration and invasion, as epithelial-mesenchymal transition (EMT) was inactivated. In vivo therapeutic effect on the innate and adaptive immune processes was validated in a subcutaneous liver cancer model by the intratumoural injection of sevelamer. Tumour growth was significantly inhibited by the partial deprivation of intratumoural Pi as the tumour microenvironment under low-Pi stress is more immunostimulatory. The anticancer immune response, activated by low-Pi stress, suggests a new macrophage-based immunotherapeutic modality.

Biological and clinical significance of the YKL-40/osteopontin-integrin β4-p70S6K axis induced by macrophages in early oesophageal squamous cell carcinoma

M2 macrophages contribute to the progression of oesophageal squamous cell carcinoma (ESCC); however, the roles of M2 macrophages in early ESCC remain unclear. To clarify the biological mechanisms underlying the interaction between M2 macrophages and oesophageal epithelial cells in early-stage ESCC, in vitro co-culture assays between the immortalised oesophageal epithelial cell line Het-1A and cytokine-defined M2 macrophages were established. Co-culture with M2 macrophages promoted the proliferation and migration of Het-1A cells via the mTOR-p70S6K signalling pathway activated by YKL-40, also known as chitinase 3-like 1, and osteopontin (OPN) that were hypersecreted in the co-culture supernatants. YKL-40 and OPN promoted the above phenotypes of Het-1A by making a complex with integrin β4 (β4). Furthermore, YKL-40 and OPN promoted M2 polarisation, proliferation, and migration of macrophages. To validate the pathological and clinical significances of in vitro experimental results, immunohistochemistry of human early ESCC tissues obtained by endoscopic submucosal dissection (ESD) was performed, confirming the activation of the YKL-40/OPN-β4-p70S6K axis in the tumour area. Moreover, epithelial expression of β4 and the number of epithelial and stromal infiltrating YKL-40- and OPN-positive cells correlated with the Lugol-voiding lesions (LVLs), a well-known predictor of the incidence of metachronous ESCC. Furthermore, the combination of high expression of β4 and LVLs or high numbers of epithelial and stromal infiltrating YKL-40- and OPN-positive immune cells could more clearly detect the incidence of metachronous ESCC than each of the parameters alone. Our results demonstrated that the YKL-40/OPN-β4-p70S6K axis played important roles in early-stage ESCC, and the high expression levels of β4 and high numbers of infiltrating YKL-40- and OPN-positive immune cells could be useful predictive parameters for the incidence of metachronous ESCC after ESD. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

The comparable tumour microenvironment in sporadic and NF2-related schwannomatosis vestibular schwannoma

Bilateral vestibular schwannoma is the hallmark of NF2-related schwannomatosis, a rare tumour predisposition syndrome associated with a lifetime of surgical interventions, radiotherapy and off-label use of the anti-angiogenic drug bevacizumab. Unilateral vestibular schwannoma develops sporadically in non-NF2-related schwannomatosis patients for which there are no drug treatment options available. Tumour-infiltrating immune cells such as macrophages and T-cells correlate with increased vestibular schwannoma growth, which is suggested to be similar in sporadic and NF2-related schwannomatosis tumours. However, differences between NF2-related schwannomatosis and the more common sporadic disease include NF2-related schwannomatosis patients presenting an increased number of tumours, multiple tumour types and younger age at diagnosis. A comparison of the tumour microenvironment in sporadic and NF2-related schwannomatosis tumours is therefore required to underpin the development of immunotherapeutic targets, identify the possibility of extrapolating ex vivo data from sporadic vestibular schwannoma to NF2-related schwannomatosis and help inform clinical trial design with the feasibility of co-recruiting sporadic and NF2-related schwannomatosis patients. This study drew together bulk transcriptomic data from three published Affymetrix microarray datasets to compare the gene expression profiles of sporadic and NF2-related schwannomatosis vestibular schwannoma and subsequently deconvolved to predict the abundances of distinct tumour immune microenvironment populations. Data were validated using quantitative PCR and Hyperion imaging mass cytometry. Comparative bioinformatic analyses revealed close similarities in NF2-related schwannomatosis and sporadic vestibular schwannoma tumours across the three datasets. Significant inflammatory markers and signalling pathways were closely matched in NF2-related schwannomatosis and sporadic vestibular schwannoma, relating to the proliferation of macrophages, angiogenesis and inflammation. Bulk transcriptomic and imaging mass cytometry data identified macrophages as the most abundant immune population in vestibular schwannoma, comprising one-third of the cell mass in both NF2-related schwannomatosis and sporadic tumours. Importantly, there were no robust significant differences in signalling pathways, gene expression, cell type abundance or imaging mass cytometry staining between NF2-related schwannomatosis and sporadic vestibular schwannoma. These data indicate strong similarities in the tumour immune microenvironment of NF2-related schwannomatosis and sporadic vestibular schwannoma.

Regulation of intrinsic and extrinsic metabolic pathways in tumour-associated macrophages

Tumour-associated macrophages (TAMs) are highly plastic and are broadly grouped into two major functional states, namely the pro-inflammatory M1-type and the pro-tumoural M2-type. Conversion of the functional states of TAMs is regulated by various cytokines, chemokines growth factors and other secreted factors in the microenvironment. Dysregulated metabolism is a hallmark of cancer. Emerging evidence suggests that metabolism governs the TAM differentiation and functional conversation in support of tumour growth and metastasis. Aside from the altered metabolism reprogramming in TAMs, extracellular metabolites secreted by cancer, stromal and/or other cells within the tumour microenvironment have been found to regulate TAMs through passive competition for metabolite availability and direct regulation via receptor/transporter-mediated signalling reaction. In this review, we focus on the regulatory roles of different metabolites and metabolic pathways in TAM conversion and function. We also discuss if the dysregulated metabolism in TAMs can be exploited for the development of new therapeutic strategies against cancer.

An immunohistochemical evaluation of tumor-associated macrophages (M1 and M2) in carcinoma prostate - An institutional study

Background

Tumor-associated macrophages (TAM) are the main component of inflammation along with leukocytes, endothelial cells and fibroblasts together form a tumor microenvironment, with immune cells representing its vital component. Many studies suggested that TAMs cumulating in tumors correlate with a poor prognosis. In prostate cancer, TAMs can increase cancer cell invasion by stimulating tumor angiogenesis, degrading the extracellular matrix, and also suppresses the antitumor functions of cytotoxic T cells resulting in poor prognosis.

Aims and Objectives

: 1. To determine the expression of M1 (CD68) and M2 (CD163) in prostate carcinoma (Pca). 2. To find the association between M1, M2 macrophage with Gleason's score and stage of Pca.

Materials and Methods

: This is a retrospective observational study. All transurethral resection prostatic (TURP) chips positive for Pca and the clinical details were collected. Radiologic findings with respect to stage of disease, size of lesion, were noted.

Results

Among the 62 cases studied, majority of the cases were in-between the age of 61-70 years. Highest cases were seen in Gleason's score 8, 9, and 10 (62%), prostatic specific antigen (PSA) levels 20-80 ng/mL (64%), tumor size 3-6 cm (51.6%), T3 stage (40.3%), N1 lymph node stage (70.9%). M1 stage of (31%). CD68 and CD163 expression was analyzed with Gleason's score, TNM stage and PSA levels. CD68 score 3 correlated with low distant and nodal metastasis 6.2% and 6.8%, respectively. CD163 score 3 correlated with high metastasis to lymph nodes and distant metastasis of 86.3% and 25%, respectively. On further analysis, statistically convincing association between the CD163 expression and Gleason's score, PSA levels, nodal and distant metastasis was found.

Conclusion

CD68 expression was correlated with good prognosis with less nodal and distant metastasis and Cd163 expression has poor outcome with increased chances of nodal and distant metastasis. Further exploration of TAM mechanisms and immune checkpoints in the prostate tumor microenvironment can furnish new light and motives for the treatment of Pca.

MiR-155 regulates M2 polarization of hepatitis B virus-infected tumour-associated macrophages which in turn regulates the malignant progression of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) initiated by hepatitis B virus (HBV) infection is a complicated process. MiR-155 can alter the immune microenvironment to affect the host's anti-infective ability. This study investigated the mechanism by which miR-155 affects tumour-associated macrophage (TAM) polarization at a molecular level, thus affecting the malignant progression of HBV⁺ HCC. MiR-155 and TAM-related cytokine expression were analysed by qRT-PCR. The distribution of TAMs was detected by immunohistochemistry. The effect of the aberrant miR-155 expression on macrophage polarization was examined by flow cytometry. The targeted relationship was verified by dual-luciferase assay, and the protein level of src homology 2 domain-containing inositol polyphosphate 5-phosphatase 1 (SHIP1) was detected by western blot. The proliferation of HCC cells was examined by CCK-8 and colony formation assays. Invasion and migration of HCC cells were detected by transwell assay. In HBV⁺ HCC tissues, miR-155 was significantly highly expressed and the number of CD206-positive TAM (CD206⁺ TAM) and CD68-positive TAM (CD68⁺ TAM) were higher than those in HBV^- HCC tissues. In addition, miR-155 overexpression significantly promoted M2-type macrophage polarization, whilst miR-155 silencing expression significantly promoted M1-type macrophage polarization. Besides, the miR-155/SHIP1 axis accelerated HCC cell invasion, proliferation and migration by inducing M2-type macrophage polarization. MiR-155 accelerates HCC cell proliferation, migration and invasion by targeting SHIP1 expression and inducing macrophage M2 polarization. This finding provides new insights into the development of novel therapeutic strategies for combatting HBV⁺ HCC and a new reference for exploring anti-tumour immunotherapy.

Inhibitory prodrug mechanism for cysteine cathepsin-targeted self-controlled drug release

Tumour-associated macrophages (TAMs) support tumour development and have emerged as important regulators of therapeutic response to cytostatic agents. To target TAMs, we have developed a novel drug delivery approach which induces drug release as it inhibits cysteine cathepsin activity. This inhibitory prodrug (IPD) approach establishes a self-regulated system where drug release stops after all cysteine cathepsins are inhibited. This could improve the therapeutic window for drugs with severe side effects. We demonstrate and characterise this self-regulation concept with a fluorogenic IPD model. Next, we applied this IPD strategy to deliver cytotoxic drugs, as doxorubicin and monomethyl auristatin E, which are efficiently released and dose-dependently eliminate RAW264.7 macrophages. Lastly, by exploiting the increased cathepsin activity in TAM-like M2-polarised primary macrophages, we show that IPD-Dox selectively eliminates M2 over M1 macrophages. This demonstrates the potential of our IPD strategy for selective drug delivery and modulation of the tumour microenvironment.

SHCBP1 Is a Prognostic Biomarker Related to the Tumour Immune Microenvironment in Pan-Cancer

OBJECTIVE

Shc SH2 domain-binding protein (SHCBP1) is involved in regulating tumour progression in a variety of tumour types. The aim of this study was to analyze the prognostic landscape of SHCBP1 in pan-cancer and investigate the relationship between SHCBP1 expression and tumour immune microenvironment.

METHODS

The Cancer Genome Atlas (TCGA) and genotype tissue expression (GTEx) database were used for obtaining the required data for the evaluation of SHCBP1 expression. The clinical characteristics and prognostic role of SHCBP1 were analyzed by using TCGA cohort. This was followed by gene set enrichment analysis by R software. Based on TCGA pan-cancer data, the correlation between SHCBP1 expression and immune infiltration, immune-related genes, microsatellite instability (MSI), and tumour mutational burden (TMB) was discussed. Finally, the half-maximum inhibitory concentration (IC₅₀) values of 192 anti-cancer drugs were obtained from the Genomics of Drug Sensitivity in Cancer (GDSC) database and their correlation with SHCBP1 was analyzed.

RESULTS

SHCBP1 was upregulated in most tumours showing a significant association with poor prognosis. Gene set enrichment analysis revealed SHCBP1 relation to the immunity, cell cycle, and cancer pathway in various types of tumour. SHCBP1 expression also showed a positive correlation with tumour-associated macrophages (TAMs) and immunosuppressive genes including TGFBR1, PD-L1 and TGFB1 and so on. In addition, high expression of SHCBP1 in patients was associated with resistance to a variety of anti-tumour drugs.

CONCLUSION

The present study confirms SHCBP1 as a poor prognostic marker of cancers. Its high expression is suggested to be involved in immunological resistance to a variety of anti-tumour drugs.

Tumour-associated macrophages heterogeneity drives resistance to clinical therapy

Tumour-associated macrophages (TAMs) constitute a plastic and heterogeneous cell population of the tumour microenvironment (TME) that can account for up to 50% of solid tumours. TAMs heterogeneous are associated with different cancer types and stages, different stimulation of bioactive molecules and different TME, which are crucial drivers of tumour progression, metastasis and resistance to therapy. In this context, understanding the sources and regulatory mechanisms of TAM heterogeneity and searching for novel therapies targeting TAM subpopulations are essential for future studies. In this review, we discuss emerging evidence highlighting the redefinition of TAM heterogeneity from three different directions: origins, phenotypes and functions. We notably focus on the causes and consequences of TAM heterogeneity which have implications for the evolution of therapeutic strategies that targeted the subpopulations of TAMs.

The Multifaceted Role of Macrophages in Oncolytic Virotherapy

One of the cancer hallmarks is immune evasion mediated by the tumour microenvironment (TME). Oncolytic virotherapy is a form of immunotherapy based on the application of oncolytic viruses (OVs) that selectively replicate in and induce the death of tumour cells. Virotherapy confers reciprocal interaction with the host’s immune system. The aim of this review is to explore the role of macrophage-mediated responses in oncolytic virotherapy efficacy. The approach was to study current scientific literature in this field in order to give a comprehensive overview of the interactions of OVs and macrophages and their effects on the TME. The innate immune system has a central influence on the TME; tumour-associated macrophages (TAMs) generally have immunosuppressive, tumour-supportive properties. In the context of oncolytic virotherapy, macrophages were initially thought to predominantly contribute to anti-viral responses, impeding viral spread. However, macrophages have now also been found to mediate transport of OV particles and, after TME infiltration, to be subjected to a phenotypic shift that renders them pro-inflammatory and tumour-suppressive. These TAMs can present tumour antigens leading to a systemic, durable, adaptive anti-tumour immune response. After phagocytosis, they can recirculate carrying tissue-derived proteins, which potentially enables the monitoring of OV replication in the TME. Their role in therapeutic efficacy is therefore multifaceted, but based on research applying relevant, immunocompetent tumour models, macrophages are considered to have a central function in anti-cancer activity. These novel insights hold important clinical implications. When optimised, oncolytic virotherapy, mediating multifactorial inhibition of cancer immune evasion, could contribute to improved patient survival.

NOD2 deficiency confers a pro-tumorigenic macrophage phenotype to promote lung adenocarcinoma progression

Nucleotide‐binding and oligomerization domain‐containing protein 2 (NOD2) was a member of the NOD‐like receptor family and played an important role in the innate immune response. Dysregulated NOD2 had been reported to contribute to tumorigenesis and progression. Here, we investigated that decreased NOD2 expressions could affect the phenotypic polarization of tumour‐associated macrophages and thus lead to the poor prognosis of lung adenocarcinoma patients. We clustered the patients by the single‐sample gene set enrichment analysis of tumour microenvironment and 13 prognostic differentially expressed immune‐related genes (PDEIRGs) were obtained based on prognostic analyses. After multiple assessments on the 13 PDEIRGs, NOD2 was considered to be the central immune gene and had a strong effect on suppressing tumour progression. Decreased NOD2 expression could be induced by cancer cells and lead to the phenotypic polarization of macrophages from protective M1 phenotype to pro‐tumorigenic M2 subtype which might be attributed to the down‐regulating of NF‐κB signalling pathway. This study draw attention to the role of inhibited innate immune function mediated by depletion of NOD2 in the TME. Our work also points to a potential strategy of NOD2‐mediated TAM‐targeted immunotherapy.

Targeting Metastatic Colorectal Cancer with Immune Oncological Therapies

Metastatic colorectal cancer carries poor prognosis, and current therapeutic regimes convey limited improvements in survival and high rates of detrimental side effects in patients that may not stand to benefit. Immunotherapy has revolutionised cancer treatment by restoring antitumoural mechanisms. However, the efficacy in metastatic colorectal cancer, is limited. A literature search was performed using Pubmed (Medline), Web of Knowledge, and Embase. Search terms included combinations of immunotherapy and metastatic colorectal cancer, primarily focusing on clinical trials in humans. Analysis of these studies included status of MMR/MSS, presence of combination strategies, and disease control rate and median overall survival. Evidence shows that immune checkpoint inhibitors, such as anti-PD1 and anti-PD-L1, show efficacy in less than 10% of patients with microsatellite stable, MMR proficient colorectal cancer. In the small subset of patients with microsatellite unstable, MMR deficient cancers, response rates were 40-50%. Combination strategies with immunotherapy are under investigation but have not yet restored antitumoural mechanisms to permit durable disease regression. Immunotherapy provides the potential to offer additional strategies to established chemotherapeutic regimes in metastatic colorectal cancer. Further research needs to establish which adjuncts to immune checkpoint inhibition can unpick resistance, and better predict which patients are likely to respond to individualised therapies to not just improve response rates but to temper unwarranted side effects.

The Immune Microenvironment of Malignant Pleural Mesothelioma: A Literature Review

Malignant pleural mesothelioma (MPM) is a rare and aggressive tumour with a poor prognosis, associated with asbestos exposure. Nowadays, treatment is based on chemotherapy with a median overall survival of less than two years. This review highlights the main characteristics of the immune microenvironment in MPM with special emphasis on recent biological advances. The MPM microenvironment is highly infiltrated by tumour-associated macrophages, mainly M2-macrophages. In line with infiltration by M2-macrophages, which contribute to immune suppression, other effectors of innate immune response are deficient in MPM, such as dendritic cells or natural killer cells. On the other hand, tumour infiltrating lymphocytes (TILs) are also found in MPM, but CD4+ and CD8+ TILs might have decreased cytotoxic effects through T-regulators and high expression of immune checkpoints. Taken together, the immune microenvironment is particularly heterogeneous and can be considered as mainly immunotolerant or immunosuppressive. Therefore, identifying molecular vulnerabilities is particularly relevant to the improvement of patient outcomes and the assessment of promising treatment approaches.

Gene and Protein Expression Is Altered by Ascorbate Availability in Murine Macrophages Cultured under Tumour-Like Conditions

Tumour-associated macrophages (TAMs) are ubiquitously present in tumours and commonly associated with poor prognosis. In immune cells, ascorbate affects epigenetic regulation, differentiation and phenotype via its co-factor activity for the 2-oxoglutarate dependent dioxygenase enzymes. Here, we determined the effect of ascorbate on TAM development in response to tumour microenvironmental cues. Naïve murine bone marrow monocytes were cultured with Lewis Lung Carcinoma conditioned media (LLCM) or macrophage colony-stimulating factor (MCSF) to encourage the development into tumour-associated macrophages. Cells were stimulated with hypoxia (1% O₂), with or without ascorbate (500 µM) supplementation. Cells and media were harvested for gene, cell surface marker and protein analyses. LLCM supported bone marrow monocyte growth with >90% of cells staining CD11b⁺F4/80⁺, indicative of monocytes/macrophages. LLCM-grown cells showed increased expression of M2-like and TAM genes compared to MCSF-grown cells, which further increased with hypoxia. In LLCM-grown cells, ascorbate supplementation was associated with increased F4/80 cell surface expression, and altered gene expression and protein secretion. Our study shows that ascorbate modifies monocyte phenotype when grown under tumour microenvironmental conditions, but this was not clearly associated with either a pro- or anti-tumour phenotype, and reflects a complex and nuanced response of macrophages to ascorbate. Overall, ascorbate supplementation clearly has molecular consequences for TAMs, but functional and clinical consequences remain unknown.

Granulocyte Colony Stimulating Factor Expression in Breast Cancer and Its Association with Carbonic Anhydrase IX and Immune Checkpoints

Simple Summary

Preclinical studies suggest that interactions between granulocyte colony-stimulating factor (G-CSF) and hypoxia-induced carbonic anhydrase IX regulate the trafficking and function of immune cells in the tumour microenvironment. We investigated the clinical significance of this crosstalk by analyzing the protein expression of G-CSF and macrophage markers by immunohistochemistry on a well-characterized tissue microarray series of invasive breast cancers. We report that high expression of G-CSF on breast carcinoma cells is linked with significantly improved survival in an important group of breast cancers that do not respond to hormonal therapy. These tumours were infiltrated by immune cells expressing biomarkers that can be targeted with immune checkpoint inhibitor drugs. In contrast, carbonic anhydrase IX expression was associated with unfavourable outcomes.

Abstract

Purpose: Granulocyte colony-stimulating factor (G-CSF) and hypoxia modulate the tumour immune microenvironment. In model systems, hypoxia-induced carbonic anhydrase IX (CAIX) has been associated with G-CSF and immune responses, including M2 polarization of macrophages. We investigated whether these associations exist in human breast cancer specimens, their relation to breast cancer subtypes, and clinical outcome. Methods: Using validated protocols and prespecified scoring methodology, G-CSF expression on carcinoma cells and CD163 expression on tumour-associated macrophages were assayed by immunohistochemistry and applied to a tissue microarray series of 2960 primary excision specimens linked to clinicopathologic, biomarker, and outcome data. Results: G-CSF_high expression showed a significant positive association with ER negativity, HER2 positivity, presence of CD163+ M2 macrophages, and CAIX expression. In univariate analysis, G-CSF_high phenotype was associated with improved survival in non-luminal cases, although the CAIX+ subset had a significantly adverse prognosis. A significant positive association was observed between immune checkpoint biomarkers on tumour-infiltrating lymphocytes and both G-CSF- and CAIX-expressing carcinoma cells. Immune checkpoint biomarkers correlated significantly with favourable prognosis in G-CSF_high/non-luminal cases independent of standard clinicopathological features. Conclusions: The prognostic associations linking G-CSF to immune biomarkers and CAIX strongly support their immunomodulatory roles in the tumour microenvironment.

Cracking the Breast Cancer Glyco-Code through Glycan-Lectin Interactions: Targeting Immunosuppressive Macrophages

The immune microenvironment of breast cancer (BC) is composed by high macrophage infiltrates, correlated with the most aggressive subtypes. Tumour-associated macrophages (TAM) within the BC microenvironment are key regulators of immune suppression and BC progression. Nevertheless, several key questions regarding TAM polarisation by BC are still not fully understood. Recently, the modulation of the immune microenvironment has been described via the recognition of abnormal glycosylation patterns at BC cell surface. These patterns rise as a resource to identify potential targets on TAM in the BC context, leading to the development of novel immunotherapies. Herein, we will summarize recent studies describing advances in identifying altered glycan structures in BC cells. We will focus on BC-specific glycosylation patterns known to modulate the phenotype and function of macrophages recruited to the tumour site, such as structures with sialylated or N-acetylgalactosamine epitopes. Moreover, the lectins present at the surface of macrophages reported to bind to such antigens, inducing tumour-prone TAM phenotypes, will also be highlighted. Finally, we will discuss and give our view on the potential and current challenges of targeting these glycan-lectin interactions to reshape the immunosuppressive landscape of BC.

High-grade tumours promote growth of other less-malignant tumours in the same prostate

Prostate cancer is a multifocal disease, but if and how individual prostate tumours influence each other is largely unknown. We therefore explored signs of direct or indirect tumour–tumour interactions in experimental models and patient samples. Low‐metastatic AT1 and high‐metastatic MatLyLu (MLL) Dunning rat prostate cancer cells were injected into separate lobes of the ventral prostate of immunocompetent rats. AT1 tumours growing in the same prostate as MLL tumours had increased tumour size and proliferation compared to AT1 tumours growing alone. In addition, the vasculature and macrophage density surrounding the AT1 tumours were increased by MLL tumour closeness. In patient prostatectomy samples, selected to contain an index tumour [tumour with the highest grade, International Society of Urological Pathology (ISUP) grade 1, 2, 3 or 4] and a low‐grade satellite tumour (ISUP grade 1), cell proliferation in low‐grade satellite tumours gradually increased with increasing histological grade of the index tumour. The density of blood vessels and CD68⁺ macrophages also increased around the low‐grade satellite tumour if a high‐grade index tumour was present. This suggests that high‐grade tumours, by changing the prostate microenvironment, may increase the aggressiveness of low‐grade lesions in the organ. Future studies are needed to explore the mechanisms behind tumour–tumour interactions and their clinical importance. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Polarization of intestinal tumour-associated macrophages regulates the development of schistosomal colorectal cancer

Tumour-associated macrophages (TAMs) can be divided into M1 and M2 TAMs. M2 TAMs play an important role in tumor progression, promoting a pro-angiogenic and immunosuppressive signal in the tumor. Previous studies have shown a correlation between schistosomiasis and colorectal cancer (CRC), but the specific mechanism has not been clarified. The differences between schistosomal CRC and non-schistosomal CRC were explored by analysing the clinicopathological data and survival time prognosis of schistosomal CRC and non-schistosomal CRC patients. The underlying mechanisms leading to the differences were investigated via tissue pathology experiments. Here, we investigated whether TAMs play a role in schistosomal CRC, leading to different clinicopathological features and prognoses in schistosomal CRC and non-schistosomal CRC patients and whether TAMs have a regulatory effect on the development and prognosis of schistosomal CRC. We found that schistosomal CRC and non-schistosomal CRC patients differ in age, sex, TNM staging and prognosis survival. Applying a logistic regression analysis model, the results showed that age, sex, pathological T stage and combined schistosomiasis were independent risk factors for CRC. Prognostic analysis of follow-up patients with schistosomal CRC found that the T stage, M stage and M2 TAMs numbers were independent prognostic factors for overall survival (OS). TAMs are significantly higher in tissues of schistosomal CRC than in non-schistosomal CRC patients, especially M2 TAMs. Studies on schistosomal colorectal tissue found that the expression of M2 TAMs increased with the malignant process of intestinal tissue. In summary, schistosomal CRC and non-schistosomal CRC patients have different clinicopathological features and prognosis, schistosomiasis is a risk factor for CRC and M2 TAMs are independent prognostic factors for OS.

Long non-coding RNA GAS5 overexpression inhibits M2-like polarization of tumour-associated macrophages in SMCC-7721 cells by promoting PTEN expression

Tumour-associated macrophage (TAM) polarization is associated with hepatocellular carcinoma but the molecular mechanism of this polarization is still unknown. Peripheral blood mononuclear cells were induced to differentiate into M0, M1 and M2 macrophages and TAMs. TAMs were transfected with pcDNA3.1-GAS5, pcDNA3.1-NC, si-GAS5, si-PTEN or si-Ctrl. A human liver cancer cell line (SMCC-7721) was incubated with the modified TAM supernatant. Quantitative real-time PCR and Western blot were performed to detect gene and protein expression. The cell proliferation and invasion properties of the SMCC-7721 cells were detected by MTT and Transwell assays. GAS5 is up-regulated in M1 macrophages and down-regulated in M2 macrophages and TAMs. GAS5 overexpression promoted M1-like polarization of TAMs and inhibited M2-like polarization of TAMs. Moreover, GAS5 promoted the expression of PTEN in TAMs. PTEN-silenced TAM supernatant treatment promoted cell proliferative and invasive properties of the SMCC-7721 cells and diminished the effect of GAS5-overexpressed TAM supernatant on the cell proliferation and invasion by SMCC-7721 cells. Our results demostrared that GAS5 overexpression inhibited M2-like polarization of TAMs by enhancing PTEN expression, thereby inhibiting cell proliferation and invasion by SMCC-7721 cells. Thus, our results suggest that GAS5 may be a new therapeutic target for HCC treatment.

Radiation therapy and the innate immune response: Clinical implications for immunotherapy approaches

Radiation therapy is an essential component of cancer care, contributing up to 40% of curative cancer treatment regimens. It creates DNA double-strand breaks causing cell death in highly replicating tumour cells. However, tumours can develop acquired resistance to therapy. The efficiency of radiation treatment has been increased by means of combining it with other approaches such as chemotherapy, molecule-targeted therapies and, in recent years, immunotherapy (IT). Cancer-cell apoptosis after radiation treatment causes an immunological reaction that contributes to eradicating the tumour via antigen presentation and subsequent T-cell activation. By contrast, radiotherapy also contributes to the formation of an immunosuppressive environment that hinders the efficacy of the therapy. Innate immune cells from myeloid and lymphoid origin show a very active role in both acquired resistance and antitumourigenic mechanisms. Therefore, many efforts are being made in order to reach a better understanding of the innate immunity reactions after radiation therapy (RT) and the design of new combinatorial IT strategies focused in these particular populations.

Macrophage-derived SPARC Attenuates M2-mediated Pro-tumour Phenotypes

Since the theory of seed and soil was put forward, people have increasingly recognized that the tumour microenvironment is an important regulator of tumour progression and therapeutic response. Among them, M2-type macrophages (M2, as the major macrophage subtype in the tumour foci) have important promoting effects on various biological behaviours. Secreted protein acidic and rich in cysteine (SPARC) is an important anti-tumour component in the microenvironment of gastric cancer. This study shows that macrophages are an important source of the SPARC and that SPARC overexpression in M2 can reduce M2-mediated promoting proliferation, migration and anti-apoptotic effects in gastric cancer. Additionally, the AKT/mTOR signalling pathways may participate in the malignant process.

Yin-yang effect of tumour cells in breast cancer: from mechanism of crosstalk between tumour-associated macrophages and cancer-associated adipocytes

Currently, adipocytes and macrophages are considered to be key cell types of breast cancer (BC) tissues. With the emergence of crown-like structures (CLS), cancer-associated adipocytes (CAAs) and tumour-associated macrophages (TAMs) are formed respectively in tumor microenvironment (TME). Both of them affect the progress of breast cancer, while forming crosstalk in the tumour tissue. CAAs play an important role, which produces hypoxia and inflammation environment and aggravates this environment. The formation and secretion of TAMs with M2 phenotypic characteristics, such as HIF-1α, and TNF-α, affect the progress of cancer cells by interfering with the secretion of MCP-1 by CAAs. Therefore, the interaction between CAAs and TAMs may be an effective therapeutic target for breast cancer. In this review, we focus on the biological effects of two types of cells in breast cancer, in order to better explain the crosstalk between them and provide new ideas for the future treatment of breast cancer.

The density of infiltrating T cells and macrophages in the parental tumour correlates with growth rate of tumoroids established from colorectal adenocarcinoma

The aim of the present study was to investigate the correlation between the density of infiltrating T cells and macrophages in the parental colorectal cancer (CRC) and the growth rate of tumoroids (i.e. a patient-derived in vitro 3D model). Tumoroids were established from fresh specimens of primary and metastatic CRC from 29 patients. The in vitro growth rate of tumoroids was monitored by automated imaging. The density of infiltrating T cells and macrophages was determined in the centre of the tumour (CT) and at the invasive margin (IM) of the parental tumours. This was performed by digital image analysis on the whole-slide scanned images using Visiopharm^® software. Tumoroids with higher density of infiltrating CD3+ lymphocytes in the IM of their parental tumour showed a higher growth rate (P < .0005). The average relative growth rate (log10) during the period from day 1 to day 11 was 0.364 ± 0.006 (mean ± SD) for the CD3+ (IM)-high group and 0.273 ± 0.008 (mean ± SD) for the CD3+ (IM)-low group. In contrast, the density of CD68+ infiltrating macrophages in the parental tumours showed significant inverse effect on the growth rate of the tumoroids (P < .0005). The present study showed that the density of immune cells in the parental CRC correlates with the growth rate of the tumoroids. The future perspective for such a 3D model could be in vitro investigations of the tumour-associated inflammatory microenvironment as well as personalized cancer immunotherapy.

High-fat diet-induced dysbiosis mediates MCP-1/CCR2 axis-dependent M2 macrophage polarization and promotes intestinal adenoma-adenocarcinoma sequence

High‐fat diet (HFD) is a well‐known risk factor for gut microbiota dysbiosis and colorectal cancer (CRC). However, evidence relating HFD, gut microbiota and carcinogenesis is limited. Our study aimed to demonstrate that HFD‐induced gut dysbiosis promoted intestinal adenoma‐adenocarcinoma sequence. In clinical study, we found that HFD increased the incidence of advanced colorectal neoplasia (AN). The expression of monocyte chemoattractant protein 1 (MCP‐1), CC chemokine receptor 2 (CCR2) and CD163 in CRC patients with HFD was significantly higher than that in CRC patients with normal diet. When it comes to the Apc^min/+ mice, HFD consumption could induce gut dysbiosis and promote intestinal carcinogenesis, accompanying with activation of MCP‐1/CCR2 axis that recruited and polarized M2 tumour‐associated macrophages. Interestingly, transfer of faecal microbiota from HFD‐fed mice to another batch of Apc^min/+ mice in the absence of HFD could also enhance carcinogenesis without significant body weight gain and induced MCP‐1/CCR2 axis activation. HFD‐induced dysbiosis could also be transmitted. Meanwhile, antibiotics cocktail treatment was sufficient to inhibit HFD‐induced carcinogenesis, indicating the vital role of dysbiosis in cancer development. Conclusively, these data indicated that HFD‐induced dysbiosis accelerated intestinal adenoma‐adenocarcinoma sequence through activation of MCP‐1/CCR2 axis, which would provide new insight into better understanding of the mechanisms and prevention for HFD‐related CRC.

The prognostic value of tumour-associated macrophages in Non-Hodgkin's lymphoma: A systematic review and meta-analysis

Tumour-associated macrophages (TAMs) play an important role in the tumour environment and were reported to be associated with poor prognosis in several tumours. However, the prognostic significance of TAMs in Non-Hodgkin's Lymphoma (NHL) remains controversial. Consequently, we aimed to evaluate the relationship between subpopulations of TAMs and clinical outcomes in NHL patients. We did a comprehensive search of the PubMed, elsevier ScienceDirect, and Cochrane databases and extracted hazard ratio (HR) and their corresponding 95% confidence intervals (95% CIs) from eligible studies. Pooling total effect value by the stata statistical software and analysing correlation of TAMs with overall survival (OS) and progression-free survival (PFS). Furthermore, subgroup analysis and sensitivity analysis were also conducted. We deemed eleven studies, including 1211 NHL patients. Our study demonstrated that high-density CD68⁺ TAMs are associated with poor OS (HR: 1.17; 95% CI, 0.81-1.54; P = .000) and poor PFS (HR: 1.15; 95% CI, 0.63-1.67; P = .000) compared with low-density CD68⁺ TAMs in the tumour microenvironment. Similarly, high-density CD163⁺ TAMs can also predict poor OS (HR: 1.52; 95% CI, 1.11-1.92; P = .000) and shorter PFS (HR: 1.52; 95% CI, 0.73-2.30; P = .000). In addition, the high CD163⁺ /CD68⁺ TAMs ratio is significantly correlated with poor OS (HR: 3.59; 95% CI, 0.77-6.40; P = .013). However, in our subgroup analysis, high-density CD68⁺ TAMs in the tumour microenvironment is associated with better OS (HR: 0.75; 95% CI, 0.41-1.09; P = .000) in NHL patients treated with rituximab chemotherapy. Our results suggest that TAMs are a robust predictor of outcomes in NHL.

SARI suppresses colitis-associated cancer development by maintaining MCP-1-mediated tumour-associated macrophage recruitment

SARI (suppressor of AP‐1, regulated by IFN) impaired tumour growth by promoting apoptosis and inhibiting cell proliferation and tumour angiogenesis in various cancers. However, the role of SARI in regulating tumour‐associated inflammation microenvironment is still elusive. In our study, the colitis‐dependent and ‐independent primary model were established in SARI deficiency mice and immuno‐reconstructive mice to investigate the functional role of SARI in regulating tumour‐associated inflammation microenvironment and primary colon cancer formation. The results have shown that SARI deficiency promotes colitis‐associated cancer (CAC) development only in the presence of colon inflammation. SARI inhibited tumour‐associated macrophages (TAM) infiltration in colon tissues, and SARI deficiency in bone marrow cells has no observed role in the promotion of intestinal tumorigenesis. Mechanism investigations indicated that SARI down‐regulates p‐STAT1 and STAT1 expression in colon cancer cells, following inhibition of MCP‐1/CCR2 axis activation during CAC development. Inverse correlations between SARI expression and macrophage infiltration, MCP‐1 expression and p‐STAT1 expression were also demonstrated in colon malignant tissues. Collectively, our results prove the inhibition role of SARI in colon cancer formation through regulating TAM infiltration.

The tumour microenvironment is immuno-tolerogenic and a principal determinant of patient outcome in EBV-positive diffuse large B-cell lymphoma

OBJECTIVE

Epstein-Barr virus-positive diffuse large B-cell lymphoma (EBV^-pos DLBCL) is a recently identified entity. Data regarding outcome to frontline immuno-chemotherapy are conflicting. Although the prognostic impact of the tumour microenvironment (TME) in EBV^-neg DLBCL is well-established, it remains untested whether the TME influences survival in EBV^-pos DLBCL. There are no data with new digital gene expression technologies that simultaneously interrogate the virus, B cells and the tumour microenvironment (TME).

METHODS

We used the NanoString™ platform in a population-based cohort of 433 patients to establish if the technology could detect EBV in the tumour biopsies and to investigate the influence that EBV has on the complex tumour microenvironment of DLBCL.

RESULTS

Incidence of EBV^-pos DLBCL was 6.9% with 5-year survival of 65% vs 82% in EBV^-neg DLBCL (P = 0.018). EBV^-pos tissues had similar expression of T-cell genes compared to EBV^-neg DLBCL but higher levels of the antigen-presenting molecule B2M. This was countered by elevated PD-L1, PD-L2, LAG3 and TIM3 immune checkpoints and a higher CD163/CD68 "M2" macrophage score.

CONCLUSION

In EBV^-pos DLBCL, the TME is immuno-tolerogenic and may explain the poor outcomes seen in this subtype of DLBCL.

Microglia and macrophages in human glioblastomas: A morphological and immunohistochemical study

Glioblastomas (GBMs), a type of highly malignant brain tumour, contain various macrophages/microglia that are known as tumour-associated macrophages (TAMs). These TAMs have various roles in tumour biology. Histopathological aspects of TAMs and associations with tumour growth assessed by magnetic resonance imaging (MRI) are poorly described. In the present study, 16 patients that had sufficient tumour tissue and histological hallmarks were examined. The tumours were classified as either slow- (n=7) or fast-growing (n=9) based on the segmented tumour volumes from MRI scans taken at diagnosis and preoperatively. Using cluster of differentiation (CD)68 and ionized calcium-binding adaptor molecule 1 (Iba1) antibodies, the number, morphology, localization and distribution of TAMs in the GBM tissue were studied. TAMs were significantly more immunoreactive for anti-Iba1 (TAMs^Iba1) compared with anti-CD68 (TAMs^CD68; P<0.001). In central tumour areas and around vessels in the infiltration zone there were more TAMs^CD68 in slow-growing tumours (P=0.003 and P=0.025, respectively). Central tumour areas contained more TAMs compared with the infiltration zone (P=0.001 for TAMs^CD68 and P<0.001 for TAMs^Iba1). The majority of TAMs exhibited a ramified phenotype in the infiltration zone, whereas central TAMs were mostly amoeboid. TAMs were present in high numbers in most regions of the tumour, whereas there were few in necrotic areas. In conclusion, the present study demonstrated and confirmed that the high numbers of TAMs in GBMs assume a range of morphologies consistent with various activation states, and that slow-growing GBMs seem to contain a TAM-population different to their fast-growing counterparts.

The Head and Neck Squamous Cell Carcinoma Microenvironment as a Potential Target for Cancer Therapy

Similarly to other types of malignant tumours, the incidence of head and neck cancer is increasing globally. It is frequently associated with smoking and alcohol abuse, and in a broader sense also with prolonged exposure to these factors during ageing. A higher incidence of tumours observed in younger populations without a history of alcohol and tobacco abuse may be due to HPV infection. Malignant tumours form an intricate ecosystem of cancer cells, fibroblasts, blood/lymphatic capillaries and infiltrating immune cells. This dynamic system, the tumour microenvironment, has a significant impact on the biological properties of cancer cells. The microenvironment participates in the control of local aggressiveness of cancer cells, their growth, and their consequent migration to lymph nodes and distant organs during metastatic spread. In cancers originating from squamous epithelium, a similarity was demonstrated between the cancer microenvironment and healing wounds. In this review, we focus on the specificity of the microenvironment of head and neck cancer with emphasis on the mechanism of intercellular crosstalk manipulation for potential therapeutic application.

Molecular model linking Th2 polarized M2 tumour-associated macrophages with deaminase-mediated cancer progression mutation signatures

A new and diverse range of somatic mutation signatures are observed in late‐stage cancers, but the underlying reasons are not fully understood. We advance a “combinatorial association model” for deaminase binding domain (DBD) diversification to explain the generation of previously observed cancer‐progression associated mutation signatures. We also propose that changes in the polarization of tumour‐associated macrophages (TAMs) are accompanied by the expression of deaminases with a new and diverse range of DBDs, and thus accounting for the generation of new somatic mutation signatures. The mechanism proposed is molecularly reminiscent of combinatorial association of heavy (H) and light (L) protein chains following V(D)J recombination of immunoglobulin molecules (and similarly for protein chains in heterodimers α/β and γ/δ of V(D)Js of T Cell Receptors) required for pathogen antigen recognition by B cells and T cells, respectively. We also discuss whether extracellular vesicles (EVs) emanating from tumour enhancing M2‐polarized macrophages represent a likely source of the de novo deaminase DBDs. We conclude that M2‐polarized macrophages extruding EVs loaded with deaminase proteins or deaminase‐specific transcription/translation regulatory factors and like information may directly trigger deaminase diversification within cancer cells, and thus account for the many new somatic mutation signatures that are indicative of cancer progression. This hypothesis now has a plausible evidentiary base, and it is worth direct testing in future investigations. A long‐term objective would be to identify molecular biomarkers predicting cancer progression (or metastatic disease) and to support the development of new drug targets before metastatic pathways are activated.

Molecular Repolarisation of Tumour-Associated Macrophages

The tumour microenvironment (TME) is composed of extracellular matrix and non-mutated cells supporting tumour growth and development. Tumour-associated macrophages (TAMs) are among the most abundant immune cells in the TME and are responsible for the onset of a smouldering inflammation. TAMs play a pivotal role in oncogenic processes as tumour proliferation, angiogenesis and metastasis, and they provide a barrier against the cytotoxic effector function of T lymphocytes and natural killer (NK) cells. However, TAMs are highly plastic cells that can adopt either pro- or anti-inflammatory roles in response to environmental cues. Consequently, TAMs represent an attractive target to recalibrate immune responses in the TME. Initial TAM-targeted strategies, such as macrophage depletion or disruption of TAM recruitment, have shown beneficial effects in preclinical models and clinical trials. Alternatively, reprogramming TAMs towards a proinflammatory and tumouricidal phenotype has become an attractive strategy in immunotherapy. This work summarises the molecular wheelwork of macrophage biology and presents an overview of molecular strategies to repolarise TAMs in immunotherapy.

Metformin's antitumour and anti-angiogenic activities are mediated by skewing macrophage polarization

Beneficial effects of metformin on cancer risk and mortality have been proved by epidemiological and clinical studies, thus attracting research interest in elucidating the underlying mechanisms. Recently, tumour‐associated macrophages (TAMs) appeared to be implicated in metformin‐induced antitumour activities. However, how metformin inhibits TAMs‐induced tumour progression remains ill‐defined. Here, we report that metformin‐induced antitumour and anti‐angiogenic activities were not or only partially contributed by its direct inhibition of functions of tumour and endothelial cells. By skewing TAM polarization from M2‐ to M1‐like phenotype, metformin inhibited both tumour growth and angiogenesis. Depletion of TAMs by clodronate liposomes eliminated M2‐TAMs‐induced angiogenic promotion, while also abrogating M1‐TAMs‐mediated anti‐angiogenesis, thus promoting angiogenesis in tumours from metformin treatment mice. Further in vitro experiments using TAMs‐conditioned medium and a coculture system were performed, which demonstrated an inhibitory effect of metformin on endothelial sprouting and tumour cell proliferation promoted by M2‐polarized RAW264.7 macrophages. Based on these results, metformin‐induced inhibition of tumour growth and angiogenesis is greatly contributed by skewing of TAMs polarization in microenvironment, thus offering therapeutic opportunities for metformin in cancer treatment.

M2-polarized tumour-associated macrophages in stroma correlate with poor prognosis and Epstein-Barr viral infection in nasopharyngeal carcinoma

OBJECTIVES

To assess the relationships between CD163 expression, localization of CD163⁺ macrophages, clinicopathological features and prognosis of NPC.

METHODS

A total of 110 cases of NPC specimens and 80 cases of nasopharyngitis specimens were analysed for CD163 expression by immunohistochemistry and EBERs expression in situ hybridization.

RESULTS

CD163 + macrophages in the tumour stroma were positively correlated with the tumour and nodal stage. Higher expression of Epstein-Barr virus-encoded RNAs (EBERs) in the nuclei of tumour cells was associated with higher density of CD163 + macrophages in the tumour stroma. More importantly, greater infiltration of CD163 + macrophages in the tumour stroma was associated with poor overall survival (OS) and poor progression-free survival (PFS). Multivariate analysis revealed that the density of CD163⁺ macrophages in the tumour stroma may be an independent risk factor for NPC prognosis.

CONCLUSIONS

Increased infiltration of CD163⁺ macrophages in the tumour stroma correlates with worse outcomes and with Epstein-Barr virus (EBV) infection status of tumour cells in nasopharyngeal carcinoma (NPC).

PD-L1 expression in extrahepatic cholangiocarcinoma

AIMS

To investigate the expression of the programmed cell death 1 (PD-1) receptor-programmed cell death ligand 1 (PD-L1) pathway and the clinicopathological characteristics in extrahepatic cholangiocarcinoma (eCCA).

METHODS AND RESULTS

Tissue samples from patients with eCCA [n = 69; perihilar cholangiocarcinoma (CCA), 40; and distal CCA, 29] who underwent surgical resection in the period from 2007 to 2015 were evaluated for PD-1, PD-L1, CD3 and CD163 expression, and correlations with clinicopathological characteristics, including survival data, were determined. PD-L1 was found on both tumour cells of eCCA (8/69, 11.6%) and tumour-associated macrophages (21/69, 30.4%). Significant correlations of PD-L1 expression on cancer cells with venous invasion (P = 0.031) and poor differentiation of the tumour (P = 0.048) were observed. In 19 of 69 (27.5%) samples, tumour-infiltrating lymphocytes (TILs) expressed PD-1, whereas infiltration with CD3-positive and CD163-positive cells was found in 63 of 69 (91.3%) and 68 of 69 (98.6%) cases, respectively. The presence of fewer than five CD3-positive cells per high-power field was significantly correlated with poorer differentiation (P = 0.015) and venous invasion (P < 0.001) of CCA. PD-L1 expression was not correlated with patient survival, but PD-L1 expression on tumour cells combined with low infiltration of CD3-positive TILs was associated with an unfavourable outcome (P = 0.027).

CONCLUSION

Only a small number of eCCA patients are PD-L1-positive, which might be important for future application of PD-1/PD-L1-targeted immune-modulating therapy in these patients. A small subgroup of eCCAs with PD-L1 expression and low lymphocytic infiltration showed more invasive growth and worse overall survival.

Selective blockade of B7-H3 enhances antitumour immune activity by reducing immature myeloid cells in head and neck squamous cell carcinoma

Immature myeloid cells including myeloid-derived suppressor cells (MDSCs) and tumour-associated macrophages (TAMs) promote tumour growth and metastasis by facilitating tumour transformation and angiogenesis, as well as by suppressing antitumour effector immune responses. Therefore, strategies designed to reduce MDSCs and TAMs accumulation and their activities are potentially valuable therapeutic goals. In this study, we show that negative immune checkpoint molecule B7-H3 is significantly overexpressed in human head and neck squamous cell carcinoma (HNSCC) specimen as compared with normal oral mucosa. Using immunocompetent transgenic HNSCC models, we observed that targeting inhibition of B7-H3 reduced tumour size. Flow cytometry analysis revealed that targeting inhibition of B7-H3 increases antitumour immune response by decreasing immunosuppressive cells and promoting cytotoxic T cell activation in both tumour microenvironment and macroenvironment. Our study provides direct in vivo evidence for a rationale for B7-H3 blockade as a future therapeutic strategy to treat patients with HNSCC.

Tumour-associated macrophage-mediated survival of myeloma cells through STAT3 activation

Overcoming drug resistance is one of the greatest challenges in the treatment of multiple myeloma (MM). The interaction of myeloma cells with the bone marrow (BM) microenvironment is a major factor contributing to drug resistance. Tumour-associated macrophages (TAMs) with different polarization states constitute an important component of this microenvironment. Previous studies have revealed a role of TAMs in MM cell survival and drug resistance; however, the impact of macrophage polarization (anti-tumoural 'M1' versus pro-tumoural 'M2'-like phenotype) in this process has not yet been described. Here, the presence of TAMs was confirmed in BM sections from MM patients, both at diagnosis and relapse, with two M2 markers, CD163 and CD206. By following different TAM subpopulations during disease progression in the syngeneic murine 5T33MM model, we demonstrated a decrease in the number of inflammatory monocytes and an increase in the number of M2-oriented TAMs in BM. Co-culture experiments demonstrated that macrophages provide a survival benefit to myeloma cells that is maintained after treatment with several classes of anti-myeloma agent (melphalan and bortezomib); the greatest effect was observed with M2-polarized macrophages. The pro-survival effect was associated with activation of the STAT3 pathway in 5T33MM cells, less cleavage of caspase-3, and thus less apoptosis. AZD1480, an ATP-competitive JAK2 inhibitor, abrogated the observed TAM-mediated MM cell survival, and partially inhibited resistance to bortezomib. Despite having only a small quantitative impact on myeloid cells in vivo, AZD1480 treatment alone and in combination with bortezomib significantly reduced tumour load. In conclusion, M2 TAMs are present in the MM microenvironment, and contribute to MM cell survival and protection from drug-induced apoptosis. As a result of TAM-induced activation of the STAT3 pathway, 5T33MM cells are sensitized to AZD1480 treatment. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Tumour-associated macrophages correlate with microvascular bed extension in colorectal cancer patients

Tumour‐associated macrophages (TAMs) represent pivotal components of tumour microenvironment promoting angiogenesis, tumour progression and invasion. In colorectal cancer (CRC), there are no conclusive data about the role of TAMs in angiogenesis‐mediated tumour progression. In this study, we aimed to evaluate a correlation between TAMs, TAM immunostained area (TAMIA) microvascular density (MVD), endothelial area (EA) and cancer cells positive to VEGF‐A (CCP‐VEGF‐A) in primary tumour tissue of locally advanced CRC patients undergone to radical surgery. A series of 76 patients with CRC were selected and evaluated by immunohistochemistry and image analysis. An anti‐CD68 antibody was employed to assess TAMs and TAMIA expression, an anti‐CD34 antibody was utilized to detect MVD and EA expression, whereas an anti‐VEGF‐A antibody was used to detect CCP‐VEGF‐A; then, tumour sections were evaluated by image analysis methods. The mean ± S.D. of TAMs, MVD and CCP‐VEGF‐A was 65.58 ± 21.14, 28.53 ± 7.75 and 63% ± 37%, respectively; the mean ± S.D. of TAMIA and EA was 438.37 ± 124.14μ² and 186.73 ± 67.22μ², respectively. A significant correlation was found between TAMs, TAMIA, MVD and EA each other (r ranging from 0.69 to 0.84; P ranging from 0.000 to 0.004). The high level of expression of TAMs and TAMIA in tumour tissue and the significant correlation with both MVD and EA illustrate that TAMs could represent a marker that plays an important role in promoting angiogenesis‐mediated CRC. In this context, novel agents killing TAMs might be evaluated in clinical trials as a new anti‐angiogenic approach.

Prognostic value of polarized macrophages in patients with hepatocellular carcinoma after curative resection

As the most predominant tumour‐infiltrating immune cells, tumour‐associated macrophages (TAMs) are significant for fostering tumour growth, progression and metastasis. CD68‐positive TAMs display dissimilarly polarized programmes comprising CD11c‐positive pro‐inflammatory macrophages (M1) and CD206‐positive immunosuppressive macrophages (M2). The aim of this study is to determine the prognostic significance of diametrically polarized TAMs in hepatocellular carcinoma (HCC) and their application to risk stratification of patients according to their specific prognostic values. This study included 80 consecutive patients with HCC, and we evaluated diametrically polarized functional status of macrophages by immunohistochemical staining of CD68, CD11c and CD206. Prognostic values and clinicopathologic features were assessed in these patients. High versus low CD11c‐positive TAM density (P = 0.005) and low versus high CD206‐positive TAM density (P = 0.002) were associated with better overall survival, whereas CD68‐positive TAM density had no prognostic significance (low versus high, P = 0.065). Furthermore, the presence of these positive staining macrophages did not show any prognostic significance for recurrence‐free survival (all P > 0.05). Multivariate Cox regression analysis identified CD11c‐positive and CD206‐positive TAMs as an independent prognostic factor (P < 0.001, P = 0.031, respectively). Intratumoural infiltration of diametrically polarized TAMs, a novel identified independent prognostic factor for survival in patients with HCC, could be combined with the TNM stage and the Barcelona Clinic Liver Cancer stage to improve a risk stratification system.

Dual targeted immunotherapy via in vivo delivery of biohybrid RNAi-peptide nanoparticles to tumour-associated macrophages and cancer cells

Lung cancer is associated with very poor prognosis and considered one of the leading causes of death worldwide. Here, we present highly potent and selective bio-hybrid RNAi-peptide nanoparticles that can induce specific and long-lasting gene therapy in inflammatory tumour associated macrophages (TAMs), via an immune modulation of the tumour milieu combined with tumour suppressor effects. Our data prove that passive gene silencing can be achieved in cancer cells using regular RNAi NPs. When combined with M2 peptide-based targeted immunotherapy that immuno-modulates TAMs cell-population, a synergistic effect and long-lived tumour eradication can be observed along with increased mice survival. Treatment with low doses of siRNA (ED50 0.0025-0.01 mg/kg) in a multi and long-term dosing system substantially reduced the recruitment of inflammatory TAMs in lung tumour tissue, reduced tumour size (∼95%) and increased animal survival (∼75%) in mice. Our results suggest that it is likely that the combination of silencing important genes in tumour cells and in their supporting immune cells in the tumour microenvironment, such as TAMs, will greatly improve cancer clinical outcomes.

Distribution and clinical significance of tumour-associated macrophages in pancreatic ductal adenocarcinoma: a retrospective analysis in China

BACKGROUND

We aimed to characterize the localization and prognostic significance of tumour-associated macrophages (tams) in pancreatic ductal adenocarcinoma (pdac).

METHODS

Tumour specimens from 70 patients with pdac and inflammatory specimens from 13 patients with chronic pancreatitis were collected and analyzed for tam and M2 macrophage counts by immunohistochemistry. Correlations between tam distributions and clinicopathologic features were determined.

RESULTS

Immunohistochemical analysis showed that tam and M2 macrophage counts were higher in tissues from pdac than from chronic pancreatitis. The tams and M2 macrophages both infiltrated more into peritumour. Both macrophage types were positively associated with lymph node metastasis (p = 0.041 for tams in peritumour, p = 0.013 for M2 macrophages in introtumour, p = 0.006 for M2 macrophage in peritumour). In addition, abdominal pain was significantly more frequent in pdac patients with a greater tams count. The survival rate was much lower in patients having high infiltration by M2 macrophages than in those having low infiltration.

CONCLUSIONS

The tam count might be associated with neural invasion in pdac, and M2 macrophages might play an important role in lymph node metastasis. Higher counts of either macrophage type were associated with increased risk of lymph node metastasis, and the M2 macrophage count could potentially be a marker for evaluating prognosis.