Macrophages In Tumor Microenvironment Research Articles

Clinical significance of CD155 expression and correlation with cellular components of tumor microenvironment in gastric adenocarcinoma.

CD155 is recently emerging as a promising target in malignancies. However, the relationship between CD155 expression and tumor microenvironment (TME) cell infiltration in gastric adenocarcinoma (GAC) has rarely been clarified. We measured CD155 expression in specimens of gastric precancerous disease and GAC by immunohistochemistry. The association of CD155 expression with GAC progression and cells infiltration in TME was evaluated through 268 GAC tissues and public dataset analysis. We showed that the expression of CD155 was positively correlated with the pathological development of gastric precancerous disease (r = 0.521, P < 0.0001). GAC patients with high CD155 expression had a poorer overall survival (P = 0.033). Moreover, CD155 expression correlated with aggressive clinicopathological features including tumor volume, tumor stage, lymph node involvement, and cell proliferation (P <0.05). Remarkably, CD155 expression positively related to the infiltration of CD68+ macrophages in TME (P = 0.011). Meanwhile, the positive correlation was observed between CD155 and CD31 (P = 0.026). In addition, patients with high CD155 expression combined with low CD3, CD4, CD8, IL-17, IFN-γ or CD19 expression as well as those with high CD155 and α-SMA expression showed significantly worse overall survival (P < 0.05). CD155 may play a pivotal role in the development of GAC through both immunological and non-immunological mechanisms and be expected to become a novel target of immunotherapy in GAC patients.

Expression of tumor-associated macrophages and PD-L1 in patients with hepatocellular carcinoma and construction of a prognostic model.

Hepatocellular carcinoma (HCC) is an inflammation-associated tumor involved in immune tolerance and evasion in the immune microenvironment. Immunotherapy can enhance the immune response of the body, break immune tolerance, and then recognize and kill tumor cells. The polarization homeostasis of M1 and M2 macrophages in tumor microenvironment (TME) is involved in the occurrence and development of tumors and has been considered a hot topic in tumor research. Programmed cell death ligand 1 (PD-L1) plays an important role in the polarity of TAM and affects the prognosis of HCC patients as a target of immunotherapy. To this end, efforts were hereby made to further explore the application value of PD-L1, M1 macrophages (CD86), and M2 macrophages (CD206) in the prognosis assessment of HCC, their correlation with immune cell infiltration in HCC tissues, and their bioenrichment function. The gene expression omnibus (GEO) and the Cancer Genome Atlas (TCGA) database were used to analyze the expression of PD-L1, CD86, and CD206 in different tumor tissues. The correlation between the expression of PD-L1, CD86, and CD206 and the infiltration of immune cells was analyzed using the Tumor Immune Estimation Resource (TIMER). The tissue specimens and clinicopathological data of hepatocellular carcinoma patients having undergone surgical treatment in our hospital were collected. Immunohistochemistry was used to verify the expression of PD-L1, CD86, and CD206, and analyze the relationship with clinicopathological features and prognosis of patients. Besides, nomogram was constructed to predict the overall survival (OS) of patients at 3 and 5years. Finally, the protein-protein interaction network information was analyzed using STRING database, and GO analysis and KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis were performed to study the biological functions of PD-L1, CD86, and CD206. Bioinformatics analysis found that PD-L1, CD86, and CD206 were underexpressed in various tumor tissues including liver cancer, while the present immunohistochemical detection found that PD-L1, CD86, and CD206 were overexpressed in liver cancer tissues. Expressions of PD-L1, CD86, and CD206 were positively correlated with the infiltration level of immune cells in liver cancer, while the expression of PD-L1 was positively correlated with the degree of tumor differentiation. Meanwhile, the expression level of CD206 was positively correlated with gender and preoperative hepatitis, and patients with high expression of PD-L1 or low expression of CD86 had poor prognosis. AJCC stage, preoperative hepatitis, and the expression levels of PD-L1 and CD86 in cancer tissues were independent risk factors affecting survival of patients after radical hepatoma surgery. KEGG pathway enrichment analysis showed that PD-L1 was significantly enriched in T cell aggregation and lymphocyte aggregation, and might be involved in the formation of T cell antigen receptor CD3 complex and cell membrane. Besides, CD86 was significantly enriched in positive regulation of cell adhesion, regulation of mononuclear cell proliferation, regulation of leukocyte proliferation, and transduction of T cell receptor signaling pathway, while CD206 was significantly enriched in type 2 immune response, cellular response to LPS, cellular response to LPS, and involvement in cellular response to LPS. In conclusion, these results suggest that PD-L1, CD86, and CD206 may be involved not only in the occurrence and development of HCC, but also in immune regulation, indicating the potential role of PD-L1 and CD86 as potential biomarkers and new therapeutic targets for prognosis assessment of liver cancer.

Artificial intelligence (AI) –powered spatial analysis of macrophages in tumor microenvironment and its association with interferon-gamma (IFNG) signature and immune phenotype (IP) in pan-cancer dataset.

2621 Background: Macrophages are known to play a crucial role in cancer progression, but few studies have reported macrophage spatial distribution and its association with genomic signatures and tumor-infiltrating lymphocytes (TIL). Here, we applied an AI-powered Whole Slide Image (WSI) analyzer in The Cancer Genome Atlas (TCGA) pan-cancer dataset to show correlation between specific localization of macrophage and anti-tumor activity, which is reflected by IFNG signature and IP based on spatial TIL density. Methods: For spatial macrophage analysis in TCGA pan-cancer dataset, we used Lunit SCOPE IO, an AI-powered H&amp;E WSI analyzer, which identifies and quantifies various classes of cells such as tumor cell, macrophage, and TIL within cancer or stroma area. IPs were defined as follows: inflamed IP (IIP) as high intratumoral TIL (iTIL) and stromal TIL (sTIL); immune-excluded IP (IEP) as low iTIL and high sTIL; immune-desert IP (IDP) as low TIL overall. The immune cell profiling and quantification of the IFNG signature score were analyzed by using CIBERSORT and RSEM. Results: In TCGA dataset (N = 7,402), median macrophage density in total TME area (tMP) was 19.9 /mm2 (interquartile range [IQR] 9.0-44.9), and it was highly enriched in lung adenocarcinoma (median 65.1, IQR 34.3-110.0), lung squamous cell carcinoma (61, 32.4-101.3), and head and neck squamous cell carcinoma (39.4, 19.6-77.3). Based on IP classification, tMP was highly enriched in IIP (37.8, 18.7-73.8) compared to IEP (25.5, 13.8-48.6) and IDP (8.9, 4.4-17.1). Interestingly, spatial analysis showed that intratumoral macrophage density (iMP) in IIP was highly enriched compared to the others (mean fold change 2.57) and the difference of stromal macrophage density (sMP) among IPs was relatively smaller (mean fold change x1.85). Classified into four groups based on median values of iMP and sMP, high-iMP/high-sMP group had the highest proportion of IIP (47.3% vs 18.7%, p &lt; 0.001), whereas low-iMP/high-sMP group had the highest one of IEP (54.9% vs 32.3%, p &lt; 0.001) compared to the others, respectively. Moreover, the high-iMP/high-sMP group had the highest level of IFNG signature score among 4 groups (x2.13 times higher, p &lt; 0.001). Notably, both iMP and sMP were significantly correlated with CD68 expression (rho 0.292 and 0.287) but CSF1R expression was more strongly correlated with iMP (rho 0.259) compared to sMP (rho 0.078). Conclusions: IIP, IFNG signature, and CSF1R expression are more strongly correlated with intratumoral macrophage density versus stromal macrophage density, suggesting a relationship between macrophage location and function in the TME warranting further investigation.

Hepatocellular carcinoma-derived FOXO1 inhibits tumor progression by suppressing IL-6 secretion from macrophages

Tumor heterogeneity dominates tumor biological behavior and shapes the tumor microenvironment. However, the mechanisms of tumor genetic features modulate immunity response were not clearly clarified. Tumor associated macrophages (TAMs) exert distinct immune functions in the progression of hepatocellular carcinoma (HCC) based on the inducible phenotype. FOXO family members sense changes in the extracellular or intracellular environment by activating a series of signaling pathways. FOXO1, a transcription factor that a common suppressor in hepatocellular carcinoma, correlated with a better tumor biological behavior in HCC through shaping macrophages anti-tumour response. Here, we found that human HCC tissue microarray (TMA) slides were employed to showed tumor derived FOXO1 negatively related with distribution of protumour macrophages. This phenomenon was confirmed in mouse xenograft model and in vitro. HCC-derived FOXO1 inhibits tumorigenesis not only by targeting tumor cells but also by synchronizing with re-educated macrophages. These effects may be partially dependent on FOXO1 transcriptionally modulates IRF-1/nitrio oxide (NO) axis in exerting effects in macrophages and decreasing IL-6 releasing from macrophages in tumor microenvironment indirectly. This feedback suppressed the progression of HCC by inactivation of IL-6/STAT3 in HCC. It implicates the potential role of FOXO1 in the therapeutic effects for modulating immune response by targeting macrophages.

Bionic lipoprotein loaded with chloroquine-mediated blocking immune escape improves antitumor immunotherapy

Tumor immunotherapy hold great promise for eradicating tumors. However, immune escape and the immunosuppressive microenvironment of tumor usually limit the efficiency of tumor immunotherapy. Therefore, simultaneously blocking immune escape and improving immunosuppressive microenvironment are the current problems to be solved urgently. Among them, CD47 on cancer cells membrane could bind to signal regulatory protein α (SIRPα) on macrophages membrane and sent out “don't eat me” signal, which was an important pathway of immune escape. The large number of M2-type macrophages in tumor microenvironment was a significant factor contributing to the immunosuppressive microenvironment. Here, we present a drug loading system for enhancing cancer immunotherapy, comprising CD47 antibody (aCD47) and chloroquine (CQ) with bionic lipoprotein (BLP) carrier (BLP-CQ-aCD47). On the one hand, as drug delivery carrier, BLP could allow CQ to be preferentially taken up by M2-type macrophages, thereby efficiently polarized M2-type tumor-promoting cells into M1-type anti-tumor cells. On the other hand, blocking CD47 from binding to SIRPα could block the “don't eat me” signal, and improve the phagocytosis of macrophages to tumor cells. Taken together, BLP-CQ-aCD47 could block immune escape, improve immunosuppressive microenvironment of tumor, and induce a strong immune response without substantial systemic toxicity. Therefore, it provides a new idea for tumor immunotherapy.

Abstract 1355: Evolution of immune tumor microenvironment (TME) from esophageal dysplasia to esophageal squamous cell carcinoma (ESCC)

Abstract Background: Previous studies have revealed esophageal dysplasia, a precancerous lesion of ESCC, harbors similar mutations and markers of genomic instability as ESCC does. This observation suggests that other factors such as evasion of immune surveillance may be involved in the progression of esophageal dysplasia to ESCC. The study aimed to identify the key differences in the immune TME between esophageal dysplasia and ESCC. Methods: Patients with a history of diagnosing with esophageal dysplasia for at least two times prior to the diagnosis of ESCC were enrolled. Formalin-fixed paraffin-embedded tissues from esophageal dysplasia diagnosed more than 6 months prior to the diagnosis of ESCC (denoted as dysplasia-1), esophageal dysplasia diagnosed within 6 months prior to the diagnosis of ESCC (denoted as dysplasia-2), and ESCC were retrieved. Transcriptomic data of esophageal dysplasia and ESCC tissues were generated by NanoString nCounter platform with Human PanCancer Immune Profiling panel, and were further analyzed for the expression levels of infiltrating immune cells by CIBERSORT. Results Six ESCC patients (M:F= 6:0), with median age of 56.6 (range: 43.3-79.1) years, were enrolled. The median time between the diagnosis of dysplasia-1 and that of ESCC was 10.2 months (range 6.0-38.6) and the median time between the diagnosis of dysplasia-2 and that of ESCC was 2.3 months (range 0.0-6.0). The analysis of immune cell signatures defined by NanoString platform revealed that multiple cell types were significantly increased in ESCC compared with dysplasia-1 (mast cell, macrophage, CD8 T cell, B cell and dendritic cell, all P &amp;lt; 0.05) and in ESCC compared with dysplasia-2 (macrophage, mast cell, dendritic cell, B cell, T cell, CD4 T cell, regulatory T cell, cytotoxic T cell, NK CD56dim cell, and T helper cell, all P &amp;lt; 0.05). There was no significant difference in the immune cell signatures between dysplasia-1 and dysplasia-2. Immune cells classified by CIBERSORT showed an increase of M2 macrophage and a decrease of M1/M2 ratio in ESCC compared with dysplasia-1 or dysplasia-2 (both P &amp;lt; 0.05). Conclusions: Our data, showing an increase of M2 macrophage in TME of ESCC compared with its precancerous esophageal dysplasia, suggest that evolution of immune TME may play a role in the progression of esophageal dysplasia to ESCC. (Funded by MOST 108-2314-B-002-076-MY3, MOST 109-2314-B-002-231-, MOHW 111-TDU-B-221-114006, NTUCCS-110-10, and NTUCCS-111-05) Citation Format: Jhe-Cyuan Guo, Chia-Lang Hsu, Yen-Lin Huang, Tsung-Che Wu, Chih-Hung Hsu. Evolution of immune tumor microenvironment (TME) from esophageal dysplasia to esophageal squamous cell carcinoma (ESCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1355.

G9a promotes immune suppression by targeting the Fbxw7/Notch pathway in glioma stem cells.

Immunotherapy for glioblastoma multiforme (GBM) is limited because of a strongly immunosuppressive tumor microenvironment (TME). Remodeling the immune TME is an effective strategy to eliminate GBM immunotherapy resistance. Glioma stem cells (GSCs) are inherently resistant to chemotherapy and radiotherapy and involved in immune evasion mechanism. This study aimed to investigate the effects of histone methyltransferases 2 (EHMT2 or G9a) on immunosuppressive TME and whether this effect was related to changes on cell stemness. Tumor-infiltrating immune cells were analyzed by flow cytometry and immunohistochemistry in orthotopic implanted glioma mice model. The gene expressions were measured by RT-qPCR, western blot, immunofluorescence, and flow cytometry. Cell viability was detected by CCK-8, and cell apoptosis and cytotoxicity were detected by flow cytometry. The interaction of G9a and F-box and WD repeat domain containing 7 (Fbxw7) promotor was verified by dual-luciferase reporter assay and chromatin immunoprecipitation. Downregulation of G9a retarded tumor growth and extended survival in an immunocompetent glioma mouse model, promoted the filtration of IFN-γ + CD4+ and CD8+ T lymphocytes, and suppressed the filtration of PD-1+ CD4+ and CD8+ T lymphocytes, myeloid-derived suppressor cells (MDSCs) and M2-like macrophages in TME. G9a inhibition decreased PD-L1 and increased MHC-I expressions by inactivating Notch pathway companying stemness decrease in GSCs. Mechanistically, G9a bound to Fbxw7, a Notch suppressor, to inhibit gene transcription through H3K9me2 of Fbxw7 promotor. G9a promotes stemness characteristics through binding Fbxw7 promotor to inhibit Fbxw7 transcription in GSCs, forming an immunosuppressive TME, which provides novel treatment strategies for targeting GSCs in antitumor immunotherapy.

Sunitinib suppresses M2 polarization of macrophages in tumor microenvironment to regulate hepatocellular carcinoma progression.

This work aimed to investigate the role and mechanism of Sunitinib (Sun) in suppressing M2 polarization of macrophages in tumor microenvironment (TME).IL-4 was applied to induce the M2 polarization of RAW264.7 cells, followed by treatment with Sun at 50and 100 nM. Flow cytometry (FCM) was conducted to detect the proportion of F4/80 + CD206 + cells. Enzyme-linked immunosorbent assay (ELISA) was performed to measure the levels of IL-10, Arg-1and VEGF. Immunofluorescence (IF) staining was carried out to detect the expression of CD206 and Arg-1. Besides, western-Blot (WB) assay was performed to measure the levels of p-JAK1 and p-STAT6 proteins. After polarization, the macrophage culture medium was employed to culture hepatocellular carcinoma (HCC) Hca-F cells. Thereafter, Transwell assays were conducted to examine cell invasion and migration, whereas plate clone formation assay was carried out to detect the clone forming capacity. In further experiments, cells were treated with the STAT6 inhibitor, or STAT6 inhibitor + Sun. Then, the polarization levels of RAW264.7 cells were detected. Moreover, this study established the xenograft tumor mouse model. Later, CD206 and Ki67 expression, IL-10, Arg-1and VEGF expression levels in tissues, and p-JAK1 and p-STAT6 protein levels were detected by histochemical staining. Sun suppressed the M2 polarization of RAW264.7 cells. Compared with IL-4 treatment, the proportion of F4/80 + CD206 + cells decreased. Meanwhile, the levels of IL-10, Arg-1and VEGF were downregulated, and the phosphorylation level of JAK1-STAT6 signaling was suppressed. After being cocultured with Hca-F, the malignant behaviors of HCC cells were suppressed after Sun treatment. Similarly, STAT6 inhibitor treatment suppressed the M2 polarization, while the combined application of Sun did not further restrain the polarization level. In the mouse model, Sun suppressed the expression of CD206 and Ki67, simultaneously inhibiting the polarization of JAK1-STAT6 signaling. Sunitinib can suppress the M2 polarization of macrophages to exert the anti-HCC effect, which is its another anticancer mechanism.

Updates in the role of the tumor microenvironment cellular crosstalk and genetic signatures in diffuse large B-cell lymphoma: a narrative review.

The tumor microenvironment (TME) is known to exert a significant impact on disease biology and convey prognostic and therapeutic implications in several hematopoietic neoplasms, including diffuse large B-cell lymphoma (DLBCL). Recent discoveries have yielded new information regarding the genetic signatures of the TME. This study aims to review the updates on the cellular markers and genetics of various components of the TME in DLBCL influencing tumor behavior and patients' responses to treatment and discuss the novel treatment modalities available for the patients. We systematically reviewed the literature in Medline for DLBCL-related articles on gene expression studies of TME. Forty-seven articles were identified and included that were published between Apr 2006 and Apr 2023. We review the key components of the TME including the endothelial cells, myofibroblasts and mast cells, and discuss their biologic roles, with a particular focus on elements of their crosstalk relevant to DLBCL. We also review the genetic changes in lymphocytes and macrophages in TME of DLBCL. Increased understanding of emergent molecular alterations may hopefully allow improved prognostication and translational discoveries which will benefit patients with aggressive B-cell lymphomas. Combining cell of origin and TME as a risk stratification/prognostication system could provide more effective targeted therapeutic regiments. Identifying TME-targeted therapies will happen after providing the TME markers in the DLBCLs.

Macrophages in Tumor Microenvironment: From Molecular Aspects to Clinical Applications

Macrophages in Tumor Microenvironment: From Molecular Aspects to Clinical Applications

489 Expression of C1q by macrophages in tumor microenvironment is associated with progression of cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the most common metastatic skin cancer. The incidence of cSCC and its precancerous forms is increasing globally. Previous studies have shown a tumor promoting function of complement system in cSCC. We have shown that C1r and C1s, components of the classical pathway, are upregulated in cSCC cells compared to normal keratinocytes and promote the growth, vascularization and invasion of cSCC tumors in vivo. Here we have investigated the expression of classical pathway component C1q in cSCC.

Metabolic Reprogramming in Tumor-Associated Macrophages in the Ovarian Tumor Microenvironment.

The interaction between tumor cells and macrophages in the tumor microenvironment plays an essential role in metabolic changes in macrophages and reprograms them towards a pro-tumorigenic phenotype. Increasing evidence indicates that macrophage metabolism is a highly complex process and may not be as simple as previously thought. Pro-inflammatory stimuli switch macrophages towards an M1-like phenotype and rely mainly on aerobic glycolysis and fatty acid synthesis, whereas anti-inflammatory stimuli switch macrophages towards an M2-like phenotype. M2-like macrophages depend more on oxidative phosphorylation (OXPHOS) and fatty acid oxidation. However, this metabolically reprogrammed phenotypic switch in macrophages remained a mystery for a while. Therefore, through this review, we tend to describe how macrophage immunometabolism determines macrophage phenotypes and functions in tumor microenvironments (TMEs). Furthermore, we have discussed how metabolic reprogramming in TAM can be used for therapeutic intervention and drug resistance in ovarian cancer.

RBM3 Induced Immune Resistance through Modulating Tumor Microenvironment in Nasopharyngeal Carcinoma

<h3>Purpose/Objective(s)</h3> We hypothesize RBM3 could lead to immune resistance in nasopharyngeal carcinoma (NPC). In the present study, we aim to explore the role and mechanisms of RBM3 inducing immune resistance by modulating tumor microenvironment (TME) in nasopharyngeal carcinoma. <h3>Materials/Methods</h3> Bioinformatic prediction and analysis were used to explore the correlation between RBM3 expression and NPC patients' survival, TME cell characters and related cytokines level. Immunohistochemistry (IHC) were used to examine RBM3 and PD-L1 expression, as well as to quantify Treg and M2 macrophages at the tissue level. Flow cytometry (FCM) were used to quantify immune cells in different treatment settings. Multiple cytokines were detected by ELISA Assays. Gene overexpression and knockdown were used to regulate RBM3 expression. Western-blot was used to detect related proteins. <h3>Results</h3> TCGA data analysis showed NPC patients with higher RBM3 expression and more Tegs had worse prognosis than those with lower RBM3 expression and fewer Tegs. IHC assays revealed that RBM3 expression was higher in immune resistant patients than in immune sensitive patients, with more Treg and M2 macrophages in TME. However, there was no significant difference in PD-L1 expression between the two groups. CNE1/IR cell line with high RBM3 expression and the parental CNE1 cell line with low RBM3 expression were cultured and cytokines in supernatant were detected. IL-2 and IL-10 levels were significantly higher in CNE1/IR cells and IL-4 and TGF-β were slightly higher. CNE1/IR and CNE1 cell lines were co-cultured with Treg and RAW264.7 cells. Flow cytometry showed there were more Treg cells and higher M2/M1 ratio in RBM3 highly expressed CNE1/IR group than the RBM3 low expression group. Decrease RBM3 expression in CNE1/IR cell could reduce IL-2/IL-10 level in supernatant and attenuate cytokines induced Treg recruit and macrophages transformation. Increase RBM3 expression in CNE1 cell could increase IL-2/IL-10 level and boost Treg recruit and macrophages transformation. Higher p-AKT level was detected in CNE1/IR cells and was correlated with IL-10 mRNA level. P-AKT and MEK1 inhibitor suppressed IL-10 mRNA and protein in RBM3 high expressing CNE1/IR cells. These results suggested RBM3 could induce immune resistant TME through regulating cytokines secretion. We further co-cultured RBM3 low expressing CNE1 cells with Treg, M2 and Treg+M2 cells. CNE1 cells co-cultured with Treg+M2 cells had higher RBM3 level than other groups, suggesting the immune resistant TME could inversely affect tumor cells and preserve immune resistant state. <h3>Conclusion</h3> RBM3 could increase NPC cells IL-10 secretion, recruiting more Tregs and increasing M1/M2 transformation in TME, thus induce immune resistance in nasopharyngeal carcinoma.

Colorectal Cancer Metastases in the Liver Establish Immunosuppressive Spatial Networking between Tumor-Associated SPP1+ Macrophages and Fibroblasts.

The liver is the most frequent metastatic site for colorectal cancer. Its microenvironment is modified to provide a niche that is conducive for colorectal cancer cell growth. This study focused on characterizing the cellular changes in the metastatic colorectal cancer (mCRC) liver tumor microenvironment (TME). We analyzed a series of microsatellite stable (MSS) mCRCs to the liver, paired normal liver tissue, and peripheral blood mononuclear cells using single-cell RNA sequencing (scRNA-seq). We validated our findings using multiplexed spatial imaging and bulk gene expression with cell deconvolution. We identified TME-specific SPP1-expressing macrophages with altered metabolism features, foam cell characteristics, and increased activity in extracellular matrix (ECM) organization. SPP1+ macrophages and fibroblasts expressed complementary ligand-receptor pairs with the potential to mutually influence their gene-expression programs. TME lacked dysfunctional CD8 T cells and contained regulatory T cells, indicative of immunosuppression. Spatial imaging validated these cell states in the TME. Moreover, TME macrophages and fibroblasts had close spatial proximity, which is a requirement for intercellular communication and networking. In an independent cohort of mCRCs in the liver, we confirmed the presence of SPP1+ macrophages and fibroblasts using gene-expression data. An increased proportion of TME fibroblasts was associated with the worst prognosis in these patients. We demonstrated that mCRC in the liver is characterized by transcriptional alterations of macrophages in the TME. Intercellular networking between macrophages and fibroblasts supports colorectal cancer growth in the immunosuppressed metastatic niche in the liver. These features can be used to target immune-checkpoint-resistant MSS tumors.

Cancer cell intrinsic TIM-3 induces glioblastoma progression

Glioblastoma (GBM) is identified to share common signal pathways between glioma and immune cells. Here, we find that Tcell immunoglobulin domain and mucin domain protein 3 (TIM-3) is one of the most common co-inhibitory immune checkpoints in GBM shared by tumor and non-tumor cells. Glioma cell-intrinsic TIM-3 is involved in not only regulating malignant behaviors of glioma cells but also inducing macrophage migration and transition to anti-inflammatory/pro-tumorigenic phenotype by a TIM-3/interleukin 6 (IL6) signal. In mechanism, as one of the major regulators of IL6, TIM-3 regulates its expression through activating NF-κB. Blocking this feedback loop by Tocilizumab, an IL6R inhibitor, inhibited the above effects and repressed the tumorigenicity of GBM invivo. Our work identifies glioma cell-intrinsic functions of TIM-3/IL6 signal mediating the crosstalk feedback loop between glioma cells and tumor-associated macrophages (TAMs). Blocking this feedback loop may provide a novel therapeutic strategy for GBM.

Macrophage-related molecular subtypes in lung adenocarcinoma identify novel tumor microenvironment with prognostic and therapeutic implications.

Background: Lung adenocarcinoma (LUAD) is a life-threatening malignant tumor, contributing for the largest cancer burden worldwide. Tumor microenvironment (TME) is composed of various immune cells, stromal cells and tumor cells, which is highly associated with the cancer prognosis and the response to immunotherapy, in which macrophages in TME have been revealing a potential target for cancer treatment. In this study, we sought to further explore the role of macrophages in LUAD progression and establish a risk model related to macrophages for LUAD. Methods: We explored immune-related pathways that might be affected by counting positively associated genes in macrophages. Molecular typing was also constructed by mining macrophage-associated genes with prognostic value through COX regression and other analyses. RiskScore prognostic models were constructed using lasso regression and stepwise multifactorial regression analysis. The differences on clinical characteristics among three subtypes (C1, C2, and C3) and RiskScore subtypes were analyzed in TCGA dataset. Immunological algorithms such as TIMER, ssGSEA, MCP-Counter, ESTIMATE, and TIDE were used to calculate the level of difference in immune infiltration between the different subtypes. The TCGA mutation dataset processed by mutect2 was used to demonstrate the frequency of mutations between different molecular subtypes. Finally, nomograms, calibration curves, and decision curves were created to assess the predictive accuracy and reliability of the model. Results: The C1 subtype demonstrated the best prognostic outcome, accompanied by higher levels of immune infiltration and lower mutation frequency, while the majority of patients in the C1 subtype were women under 65 years of age. Myeloid-derived suppressor cell (MDSC) scores were higher in the C3 subtype, suggesting a more severe immune escape, which may have contributed to the tumor evading the immune system resulting in a poorer prognosis for patients. In addition, our RiskScore prognostic model had good predictive accuracy and reliability. Conclusion: This paper provides a study of macrophage-related pathways, immunosuppression, and their mechanisms of action in lung cancer, along with targets for future treatment to guide the optimal treatment of lung cancer.

CD36-mediated metabolic crosstalk between tumor cells and macrophages affects liver metastasis

Liver metastasis is highly aggressive and treatment-refractory, partly due to macrophage-mediated immune suppression. Understanding the mechanisms leading to functional reprogramming of macrophages in the tumor microenvironment (TME) will benefit cancer immunotherapy. Herein, we find that the scavenger receptor CD36 is upregulated in metastasis-associated macrophages (MAMs) and deletion of CD36 in MAMs attenuates liver metastasis in mice. MAMs contain more lipid droplets and have the unique capability in engulfing tumor cell-derived long-chain fatty acids, which are carried by extracellular vesicles. The lipid-enriched vesicles are preferentially partitioned into macrophages via CD36, that fuel macrophages and trigger their tumor-promoting activities. In patients with liver metastases, high expression of CD36 correlates with protumoral M2-type MAMs infiltration, creating a highly immunosuppressive TME. Collectively, our findings uncover a mechanism by which tumor cells metabolically interact with macrophages in TME, and suggest a therapeutic potential of targeting CD36 as immunotherapy for liver metastasis.

A Novel Metabolism-Related Gene Signature for Predicting the Prognosis of HBV-Infected Hepatocellular Carcinoma

Metabolic reprogramming is one of the crucial hallmarks of cancer. Hepatocellular carcinoma (HCC) resulting from hepatitis B has various altered metabolic features. However, the impact of such alterations on the tumor microenvironment (TME) and immunotherapy efficacy is still unclear. Here, a prognostic signature of metabolism-related gene (MRG) composition was constructed, and the immune profile of different subgroups and potential response to immunotherapy were described. Based on the HCC gene dataset, we used weighted gene coexpression network analysis for identifying MRGs linked to hepatitis B. An MRG prognostic index (MRGPI) with two genes, ATIC and KIF2C, was constructed using Cox regression analysis, an independent prognostic factor. In addition, the model was validated using the GEO dataset. The immune profile and prediction of HCC response to immunotherapy in different subgroups were analyzed using CIBERSORT and TIDE. Based on the outcomes, the distributions of memory B cells, monocytes, resting mast cells, and M0 macrophages in TME were different with a greater benefit of immunotherapy in the low MRGPI risk group. In addition, the MRGPI risk groups showed substantial differences in sensitivity to conventional drug therapy. This study concludes that MRGPI is an effective biomarker for predicting the prognoses of patients with HCC resulting from hepatitis B virus infections and determining the efficacy of immunotherapy and conventional medical therapy.

Circular RNA circWWC3 augments breast cancer progression through promoting M2 macrophage polarization and tumor immune escape via regulating the expression and secretion of IL-4

Interaction between tumor cells and tumor microenvironment (TME) is critical to promote tumor progression and metastasis. As the most abundant immune cells in TME, macrophages can be polarized into M2-like tumor-associated macrophages (TAMs) which further promote tumor progression. However, to date, the molecular mechanisms of TAM polarization in TME are still largely unknown. In the present study, we revealed that circular RNA circWWC3 could up-regulate the expression and secretion of IL-4 in breast cancer cells. Enhanced secretion of IL-4 from breast cancer cells could augment the M2-like polarization of macrophages in TME, which further promotes the migration of breast cancer cells. In addition, increased secretion of IL-4 from breast cancer cells could induce the expression PD-L1 in M2 macrophages. Moreover, up-regulated IL-4 also enhanced the expression of PD-L1 in breast cancer cells, which further facilitates breast cancer immune evasion. Though analyzing the expression of circWWC3, IL-4, PD-L1, and CD163 in 140 cases of breast cancer tissues, we found that high expression of circWWC3 was associated with poor overall survival and disease-free survival of breast cancer patients. Breast cancer patients with circWWC3high/PD-L1high breast cancer cells and CD163high macrophages had a poorer overall survival and disease-free survival. Conclusively, circWWC3 might augment breast cancer progression through promoting M2 macrophage polarization and tumor immune escape via regulating the expression and secretion of IL-4. CircWWC3 might be a potential therapeutic target in breast cancer.

Epigenetic regulation of cutaneous T-cell lymphoma is mediated by dysregulated lncRNA MALAT1 through modulation of tumor microenvironment.

Cutaneous T-Cell Lymphoma (CTCL) is a rare non-Hodgkin lymphoma marked by migration of T-lymphocytes to the skin. It has many subtypes some of which are aggressive with documented metastasis. We investigated a possible role of lncRNA MALAT1 in CTCL cells because of its documented involvement in cancer metastasis. A screening of MALAT1 in CTCL patients revealed its elevated levels in the patients, compared to healthy individuals. For our investigation, we employed HH and H9 CTCL cells and silenced MALAT1 to understand the MALAT1 mediated functions. Such silencing of MALAT1 resulted in reversal of EMT and inhibition of cancer stem cell phenotype, along with reduced cell growth and proliferation. EMT reversal was established through increased E-cadherin and reduced N-cadherin while inhibition of cancer stem cell phenotype was evident through reduced Sox2 and Nanog. CTCL patients had higher circulating levels of IL-6, IL-8, IL-10, TGFβ, PGE2 and MMP7 which are factors released by tumor-associated macrophages in tumor microenvironment. MALAT1 sponged miR-124 as this tumor suppressive miRNA was de-repressed upon MALAT1 silencing. Moreover, downregulation of miR-124 attenuated MALAT1 silencing effects. Our study provides a rationale for further studies focused on an evaluation of MALAT1-miR-124 in CTCL progression.