Components Of Microenvironment Research Articles

PDPN/CCL2/STAT3 feedback loop alter CAF heterogeneity to promote angiogenesis in colorectal cancer.

Colorectal cancer (CRC) is one of the common clinical malignancies and the fourth leading cause of cancer-related death in the world. The tumor microenvironment (TME) plays a crucial role in promoting tumor angiogenesis, and cancer-associated fibroblasts (CAFs) are one of the key components of the tumor microenvironment. However, due to the high heterogeneity of CAFs, elucidating the molecular mechanism of CAF-mediated tumor angiogenesis remained elusive. In our study, we found that there is pro-angiogenic functional heterogeneity of CAFs in colorectal cancer and we clarified that Podoplanin (PDPN) can specifically label CAF subpopulations with pro-angiogenic functions. We also revealed that PDPN + CAF could maintain CAF heterogeneity by forming a PDPN/CCL2/STAT3 feedback loop through autocrine CCL2, while activate STAT3 signaling pathway in endothelial cells to promote angiogenesis through paracrine CCL2. We demonstrated WP1066 could inhibit colorectal cancer angiogenesis by blocking both the PDPN/CCL2/STAT3 feedback loop in CAFs and the STAT3 signaling pathway in endothelial cells. Altogether, our study suggests that STAT3 could be a potential therapeutic target for blocking angiogenesis in colorectal cancer. We provide theoretical basis and new therapeutic strategies for the clinical treatment of colorectal cancer.

30 Synergistic systematic analysis with fully human tissue models andin silico modeling of “copycats” reveals mechanisms of T cell suppression in clear cell renal cell carcinoma

Abstract Background Immune checkpoint-inhibitors have become a standard treatment for clear cell renal cell carcinoma (ccRCC). However, responses to checkpoint-inhibition are heterogeneous and many patients are resistant or eventually develop resistance. A better understanding of functional mechanisms governing immune responses in ccRCC is needed to identify biomarkers for therapeutic responses and to unravel novel therapeutic targets to overcome primary or acquired resistance to therapies. Methods We developed a fully human explant model derived from freshly resected ccRCC tissue (Fig. 1A). Our tissue explant model preserves all components of the tumor microenvironment including not only tumor cells, but also the immune cell compartment as well as tumor-stroma and -vasculature in culture (Fig. 1B). Following treatment with combined checkpoint-inhibition (Nivolumab plus Ipilimumab) or an anti-CCR5 inhibitor (Maraviroc), the tissue explants were analyzed by immunohistochemistry staining and multiplex cytokine profiling of 50 cytokines. Spatial and functional insights were incorporated in an agent-based in silico model (PhysiCell, Ghaffarizadeh et al., PLoS Comput. Biol., 2018) for unlimited exploration of functional cellular dynamics in the tumor microenvironment (Fig. 1D). Results Immunohistochemical analyses and cytokine profiling of ccRCC-tissue explants showed heterogeneous immune responses among different patients and indicated an impaired cytotoxic T cell response following checkpoint-inhibition (Fig. 1C). Spatial analyses of immune cell populations revealed clusters of CD8+ T cells and CD163+ macrophages localized closely to CD31+ endothelial cells. Further characterization of the tumor microenvironment revealed high CCR5-expression in the tumor, particularly on the tumor blood vessels (Fig. 1B). Treatment of the tissue explants with the anti-CCR5 inhibitor Maraviroc led to an increase of CD8+ T cells and cytotoxic cytokines (Granzyme B, IFNgamma, TNFalpha, IFNalpha2) in the tumor in comparison to checkpoint-inhibition (Fig. 1C). Spatial and functional information from cultured ccRCC-tissue explants were integrated into an agent-based in silico model of the ccRCC tumor microenvironment, which includes tumor cells, T cells, macrophages and endothelial cells (Fig. 1D). In silico simulation of different immune cell modulating treatment conditions showed an increase of T cells and cytotoxic cytokines upon blockade of the interaction between T cells with endothelial cells or macrophages (Fig. 1E). Conclusions Our combined ex vivo and in silico analyses provide evidence for immunosuppression in the ccRCC tumor microenvironment mediated by macrophages and endothelial cells. CCR5 was shown to be a potential target to overcome immune resistance to checkpoint-inhibition in ccRCC. Further characterization of immune cell compositions and functional mechanisms in the perivascular area is imperative to enhance therapeutic responses to immunotherapies for ccRCC.

Evaluation of the Immune Response within the Tumor Microenvironment in African American and non-Hispanic White Non-Small Cell Lung Cancer Patients.

African Americans have higher incidence and mortality from lung cancer than non-Hispanic Whites, but investigations into differences in immune response have been minimal. Therefore, we compared components of the tumor microenvironment among African Americans and non-Hispanic Whites diagnosed with non-small cell lung cancer (NSCLC) based on PD-L1 or tertiary lymphoid structure (TLS) status to identify differences of translational relevance. Using a cohort of 280 NSCLC patients from the INHALE study (non-Hispanic White: n=155; African American: n=125), we evaluated PD-L1 tumor proportion score (<1% vs. ≥1%) and TLS status (presence/absence), comparing differences within the tumor microenvironment based on immune cell distribution and differential expression of genes. Tumors from African Americans had a higher proportion of plasma cell signatures within the tumor microenvironment than non-Hispanic Whites. In addition, gene expression patterns in African American PD-L1 positive samples suggest these tumors contained greater numbers of γδ T-cells and resting dendritic cells, along with fewer CD8+ T-cells after adjusting for age, sex, pack-years, stage, and histology. Investigation of differential expression of B-cell/plasma cell related genes between the two patient populations revealed that two immunoglobulin genes (IGKV2-29 and IGLL5) were associated with decreased mortality risk in African Americans. In the first known race-stratified analysis of tumor microenvironment components in lung cancer based on PD-L1 expression or TLS status, differences within the immune cell composition and transcriptomic signature were identified that may have therapeutic implications. Future investigation of racial variation within the tumor microenvironment may help direct the use of immunotherapy.

Research advances on signaling pathways regulating the polarization of tumor-associated macrophages in lung cancer microenvironment

Lung cancer (LC) is one of the most common cancer worldwide. Tumor-associated macrophages (TAMs) are important component of the tumor microenvironment (TME) and are closely related to the stages of tumor occurrence, development, and metastasis. Macrophages are plastic and can differentiate into different phenotypes and functions under the influence of different signaling pathways in TME. The classically activated (M1-like) and alternatively activated (M2-like) represent the two polarization states of macrophages. M1 macrophages exhibit anti-tumor functions, while M2 macrophages are considered to support tumor cell survival and metastasis. Macrophage polarization involves complex signaling pathways, and blocking or regulating these signaling pathways to enhance macrophages’ anti-tumor effects has become a research hotspot in recent years. At the same time, there have been new discoveries regarding the modulation of TAMs towards an anti-tumor phenotype by synthetic and natural drug components. Nanotechnology can better achieve combination therapy and targeted delivery of drugs, maximizing the efficacy of the drugs while minimizing side effects. Up to now, nanomedicines targeting the delivery of various active substances for reprogramming TAMs have made significant progress. In this review, we primarily provided a comprehensive overview of the signaling crosstalk between TAMs and various cells in the LC microenvironment. Additionally, the latest advancements in novel drugs and nano-based drug delivery systems (NDDSs) that target macrophages were also reviewed. Finally, we discussed the prospects of macrophages as therapeutic targets and the barriers to clinical translation.

POSTN+ cancer-associated fibroblasts determine the efficacy of immunotherapy in hepatocellular carcinoma

ObjectiveHepatocellular carcinoma (HCC) poses a significant clinical challenge because the long-term benefits of immune checkpoint blockade therapy are limited. A comprehensive understanding of the mechanisms underlying immunotherapy resistance in HCC...

A novel cancer-associated fibroblast signature for kidney renal clear cell carcinoma via integrated analysis of single-cell and bulk RNA-sequencing

Cancer-associated fibroblasts (CAFs), integral components of the tumor microenvironment, play a pivotal role in tumor proliferation, metastasis, and clinical outcomes. However, its specific roles in Kidney Renal Clear Cell Carcinoma (KIRC) remain poorly understood. Employing the established Seurat single-cell analysis pipeline, we identified 21 CAFs marker genes. Subsequently, a prognostic signature consisting of 6 CAFs marker genes (RGS5, PGF, TPM2, GJA4, SEPT4, and PLXDC1) was developed in a cohort through univariate and LASSO Cox regression analyses. The model’s efficacy was then validated in an external cohort, with a remarkable predictive performance in 1-, 3-, and 5-year. Patients in the high-risk group exhibited significantly inferior survival outcomes (p < 0.001), and the risk score was an independent prognostic factor (p < 0.05). Distinct differences in immune cell profiles and drug susceptibility were observed between the two risk groups. In KIRC, the PGF-VEGFR1 signaling pathway displayed a notable increase. PGF expression was significantly elevated in tumor tissues, as demonstrated by quantitative real-time polymerase chain reaction. In vitro, transwell assays and CCK8 revealed that recombinant-PGF could enhance the capability of cell proliferation, migration, and invasion in 769P and 786-O cells. This study firstly developed a novel predictive model based on 6 CAFs genes for KIRC. Additionally, PGF may present a potential therapeutic target to enhance KIRC treatment.

Visible light photo-crosslinking of biomimetic gelatin-hyaluronic acid hydrogels for adipose tissue engineering

Tissue engineering (TE) of adipose tissue (AT) is a promising strategy that can provide 3D constructs to be used for in vitro modelling, overcoming the limitations of 2D cell cultures by closely replicating the complex breast tissue extracellular matrix (ECM), cell-cell, and cell-ECM interactions. However, the challenge in developing 3D constructs of AT resides in designing artificial matrices that can mimic the structural properties of native AT and support adipocytes biological functions. Herein, we developed photocrosslinkable hydrogels by employing gelatin methacrylate (GelMA) and hyaluronic acid methacrylate (HAMA) to mimic the collagenous and glycosaminoglycan components of AT microenvironment, respectively. The physico-mechanical properties of the hydrogels were tuned to target AT biomimetic properties by varying the hydrogel formulation (with or without hyaluronic acid), and the amount of photoinitiator (ruthenium/sodium persulfate) used to crosslink the hydrogels via visible light. The physical and mechanical properties of the developed hydrogels were tuned by varying the material formulation and the photoinitiator concentration. Preadipocytes were encapsulated inside the hydrogels and differentiated into mature adipocytes. Findings enlightened that HAMA addition in hybrid hydrogels boosted an increased lipid accumulation. The engineered biomimetic adipocyte-based constructs resulted promising as scaffolds or 3D in vitro models of AT.

Targeting the bone marrow niche, moving towards leukemia eradication

Hematopoiesis is a complex and tightly regulated process that drives the formation of mature blood cells from a single hematopoietic stem cell. This complex process occurs within the bone marrow, which, once disrupted or deregulated, subverts normal hematopoietic development, allowing leukemic cells to emerge, proliferate, and thrive. Notably, several cellular populations and paracrine factors within the bone marrow fuel leukemia expansion and progression. This review presents an overview of the main microenvironmental components that promote myeloid leukemia progression, discussing the emerging therapeutical strategies that target both leukemic cells and the supportive bone marrow microenvironment – targeting both the seed and the soil.

IL-1R signaling drives enteric glia-macrophage interactions in colorectal cancer

Enteric glia have been recently recognized as key components of the colonic tumor microenvironment indicating their potential role in colorectal cancer pathogenesis. Although enteric glia modulate immune responses in other intestinal diseases, their interaction with the colorectal cancer immune cell compartment remains unclear. Through a combination of single-cell and bulk RNA-sequencing, both in murine models and patients, here we find that enteric glia acquire an immunomodulatory phenotype by bi-directional communication with tumor-infiltrating monocytes. The latter direct a reactive enteric glial cell phenotypic and functional switch via glial IL-1R signaling. In turn, tumor glia promote monocyte differentiation towards pro-tumorigenic SPP1+ tumor-associated macrophages by IL-6 release. Enteric glia cell abundancy correlates with worse disease outcomes in preclinical models and colorectal cancer patients. Thereby, our study reveals a neuroimmune interaction between enteric glia and tumor-associated macrophages in the colorectal tumor microenvironment, providing insights into colorectal cancer pathogenesis.

Investigating the effect of Fusobacterium nucleatum on the aggressive behavior of cancer-associated fibroblasts in colorectal cancer

Fusobacterium nucleatum, (F. nucleatum) as a known factor in inducing oncogenic, invasive, and inflammatory responses, can lead to an increase in the incidence and progression of colorectal cancer (CRC). Cancer-associated fibroblasts (CAF) are also one of the key components of the tumor microenvironment (TME), which lead to resistance to treatment, metastasis, and disease recurrence with their markers, secretions, and functions. This study aimed to investigate the effect of F. nucleatum on the invasive phenotype and function of fibroblast cells isolated from normal and cancerous colorectal tissue. F. nucleatum bacteria were isolated from deep periodontal pockets and confirmed by various tests. CAF cells from tumor tissue and normal fibroblasts (NF) from a distance of 10 cm of tumor tissue were isolated from 5 patients by the explant method and were exposed to secretions and ghosts of F. nucleatum. The expression level of two markers, fibroblast activation protein (FAP), and α-smooth muscle actin (α-SMA), and the amount of production of two cytokines TGF-β and IL-6 from fibroblast cells were measured by flow cytometry and ELISA test, respectively before and after exposure to different bacterial components. The expression of the FAP marker was significantly higher in CAF cells compared to NF cells (P < 0.05). Also, the expression of IL-6 in CAF cells was higher than that of NF cells. In investigating the effect of bacterial components on the function of fibroblastic cells, after comparing the amount of IL-6 produced between the normal tissue of each patient and his tumoral tissue under 4 treated conditions, it was found that the amount of IL-6 production from the CAF cells of patients in the control group, treated with heat-killed ghosts and treated with paraformaldehyde-fixed ghosts had a significant increase compared to NF cells (P < 0.05). Due to the significant increase in FAP marker expression in fibroblast cells of tumor tissue compared to normal tissue, it seems that FAP can be used as a very good therapeutic marker, especially in patients with high levels of CAF cells. Various components of F. nucleatum could affect fibroblast cells differentially and at least part of the effect of this bacterium in the TME is mediated by CAF cells.

Integrating single-cell RNA-seq to identify fibroblast-based molecular subtypes for predicting prognosis and therapeutic response in bladder cancer.

Bladder cancer (BLCA) is a highly aggressive and heterogeneous disease, posing challenges for diagnosis and treatment. Cancer immunotherapy has recently emerged as a promising option for patients with advanced and drug-resistant cancers. Fibroblasts, a significant component of the tumor microenvironment, play a crucial role in tumor progression, but their precise function in BLCA remains uncertain. Single-cell RNA sequencing (scRNA-seq) data for BLCA were obtained from the Gene Expression Omnibus database. The R package "Seurat" was used for processing scRNA-seq data, with uniform manifold approximation and projection (UMAP) for downscaling and cluster identification. The FindAllMarkers function identified marker genes for each cluster. Differentially expressed genes influencing overall survival (OS) of BLCA patients were identified using the limma package. Differences in clinicopathological characteristics, immune microenvironment, immune checkpoints, and chemotherapeutic drug sensitivity between high- and low-risk groups were investigated. RT-qPCR and immunohistochemistry validated the expression of prognostic genes. Fibroblast marker genes identified three molecular subtypes in the testing set. A prognostic signature comprising ten genes stratified BLCA patients into high- and low-score groups. This signature was validated in one internal and two external validation sets. High-score patients exhibited increased immune cell infiltration, elevated chemokine expression, and enhanced immune checkpoint expression but had poorer OS and a reduced response to immunotherapy. Six sensitive anti-tumor drugs were identified for the high-score group. RT-qPCR and immunohistochemistry showed that CERCAM, TM4SF1, FN1, ANXA1, and LOX were highly expressed, while EMP1, HEYL, FBN1, and SLC2A3 were downregulated in BLCA. A novel fibroblast marker gene-based signature was established, providing robust predictions of survival and immunotherapeutic response in BLCA patients.

Local therapy in glioma: An evolving paradigm from history to horizons (Review).

Despite the implementation of multimodal treatments after surgery, glioblastoma (GBM) remains an incurable disease, posing a significant challenge in neuro-oncology. In this clinical setting, local therapy (LT), a developing paradigm, has received significant interest over time due to its potential to overcome the drawbacks of conventional therapy options for GBM. The present review aimed to trace the historical development, highlight contemporary advances and provide insights into the future horizons of LT in GBM management. In compliance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols criteria, a systematic review of the literature on the role of LT in GBM management was conducted. A total of 2,467 potentially relevant articles were found and, after removal of duplicates, 2,007 studies were screened by title and abstract (Cohen's κ coefficient=0.92). Overall, it emerged that 15, 10 and 6 clinical studies explored the clinical efficiency of intraoperative local treatment modalities, local radiotherapy and local immunotherapy, respectively. GBM recurrences occur within 2 cm of the radiation field in 80% of cases, emphasizing the significant influence of local factors on recurrence. This highlights the urgent requirement for LT strategies. In total, three primary reasons have thus led to the development of numerous LT solutions in recent decades: i) Intratumoral implants allow the blood-brain barrier to be bypassed, resulting in limited systemic toxicity; ii) LT facilitates bridging therapy between surgery and standard treatments; and iii) given the complexity of GBM, targeting multiple components of the tumor microenvironment through ligands specific to various elements could have a synergistic effect in treatments. Considering the spatial and temporal heterogeneity of GBM, the disease prognosis could be significantly improved by a combination of therapeutic strategies in the era of precision medicine.

Establishment of advanced tumor organoids with emerging innovative technologies

Tumor organoids have emerged as a crucial preclinical model for multiple cancer research. Their high establishment rates, stability, and ability to replicate key biological features of original tumor cells in vivo render them invaluable for exploring tumor molecular mechanisms, discovering potential anti-tumor drugs, and predicting clinical drug efficacy. Here, we review the establishment of tumor organoid models and provide an extensive overview of organoid culturing strategies. We also emphasize the significance of integrating cellular components of the tumor microenvironment and physicochemical factors in the organoid culturing system, highlighting the importance of artificial intelligence technology in advancing organoid construction. Moreover, we summarize recent advancements in utilizing organoid systems for novel anti-cancer drug screening and discuss promising trends for enhancing advanced organoids in next-generation disease modeling.

The multifaceted role of PCSK9 in cancer pathogenesis, tumor immunity, and immunotherapy.

Proprotein convertase subtilisin/kexin type 9 (PCSK9), a well-known regulator of cholesterol metabolism and cardiovascular diseases, has recently garnered attention for its emerging involvement in cancer biology. The multifunctional nature of PCSK9 extends beyond lipid regulation and encompasses a wide range of cellular processes that can influence cancer progression. Studies have revealed that PCSK9 can modulate signaling pathways, such as PI3K/Akt, MAPK, and Wnt/β-catenin, thereby influencing cellular proliferation, survival, and angiogenesis. Additionally, the interplay between PCSK9 and cholesterol homeostasis may impact membrane dynamics and cellular migration, further influencing tumor aggressiveness. The central role of the immune system in monitoring and controlling cancer is increasingly recognized. Recent research has demonstrated the ability of PCSK9 to modulate immune responses through interactions with immune cells and components of the tumor microenvironment. This includes effects on dendritic cell maturation, T cell activation, and cytokine production, suggesting a role in shaping antitumor immune responses. Moreover, the potential influence of PCSK9 on immune checkpoints such as PD1/PD-L1 lends an additional layer of complexity to its immunomodulatory functions. The growing interest in cancer immunotherapy has prompted exploration into the potential of targeting PCSK9 for therapeutic benefits. Preclinical studies have demonstrated synergistic effects between PCSK9 inhibitors and established immunotherapies, offering a novel avenue for combination treatments. The strategic manipulation of PCSK9 to enhance tumor immunity and improve therapeutic outcomes presents an exciting area for further investigations. Understanding the mechanisms by which PCSK9 influences cancer biology and immunity holds promise for the development of novel immunotherapeutic approaches. This review aims to provide a comprehensive analysis of the intricate connections between PCSK9, cancer pathogenesis, tumor immunity, and the potential implications for immunotherapeutic interventions.

Multi-omics reveals the impact of cancer-associated fibroblasts on the prognosis and treatment response of adult diffuse highest-grade gliomas

BackgroundCancer associated fibroblasts (CAF), an important cancer-promoting and immunosuppressive component of the tumor immune microenvironment (TIME), have recently been found to infiltrate adult diffuse highest-grade gliomas (ADHGG) (gliomas of grade IV). MethodsGene expression and clinical data of ADHGG patients were obtained from the CGGA and TCGA databases. Consensus clustering was used to identify CAF subtypes based on CAF key genes acquired from single-cell omics and spatial transcriptomomics. CIBERSORT, ssGSEA, MCPcounter, and ESTIMATE analyses were used to assess the TIME of GBM. Survival analysis, drug sensitivity analysis, TCIA database, TIDE and cMap algorithms were used to compare the prognosis and treatment response between patients with different CAF subtypes. An artificial neural network (ANN) model based on random forest was constructed to exactly identify CAF subtypes, which was validated in a real-world patient cohort of ADHGG. ResultsConsensus clustering classified ADHGG into two CAF subtypes. Compared with subtype B, patients with ADHGG subtype A had a poorer prognosis, worse responsiveness to immunotherapy and radiotherapy, higher CAF infiltration in TIME, but higher sensitivity to temozolomide. Furthermore, patients with subtype A had a much lower proportion of IDH mutations. Finally, the ANN model based on five genes (COL3A1, COL1A2, CD248, FN1, and COL1A1) could exactly discriminate CAF subtypes, and the validation of the real-world cohort indicated consistent results with the bioinformatics analyses. ConclusionThis study revealed a novel CAF subtype to distinguish ADHGG patients with different prognosis and treatment responsiveness, which may be helpful for accurate clinical decision-making of ADHGG.

AI-Based multimodal Multi-tasks analysis reveals tumor molecular heterogeneity, predicts preoperative lymph node metastasis and prognosis in papillary thyroid carcinoma: A retrospective study.

Papillary thyroid carcinoma (PTC) is the predominant form of thyroid cancer globally, especially when lymph node metastasis (LNM) occurs. Molecular heterogeneity, driven by genetic alterations and tumor microenvironment components, contributes to the complexity of PTC. Understanding these complexities is essential for precise risk stratification and therapeutic decisions. This study involved a comprehensive analysis of 521 patients with PTC from our hospital and 499 patients from The Cancer Genome Atlas (TCGA). The real-world cohort 1 comprised 256 patients with stage I-III PTC. Tissues from 252 patients were analyzed by DNA-based next-generation sequencing, and tissues from four patients were analyzed by single-cell RNA sequencing (scRNA-seq). Additionally, 586 PTC pathological sections were collected from TCGA, and 275 PTC pathological sections were collected from the real-world cohort 2. A deep learning multimodal model was developed using matched histopathology images, genomic, transcriptomic, and immune cell data to predict LNM and disease-free survival (DFS). This study included a total of 1,011 PTC patients, comprising 256 patients from cohort 1, 275 patients from cohort 2, and 499 patients from TCGA. In cohort 1, we categorized PTC into four molecular subtypes based on BRAF, RAS, RET, and other mutations. BRAF mutations were significantly associated with LNM and impacted DFS. ScRNA-seq identified distinct T cell subtypes and reduced B cell diversity in BRAF-mutated PTC with LNM. The study also explored cancer-associated fibroblasts and macrophages, highlighting their associations with LNM. The deep learning model was trained using 405 pathology slides and RNA sequences from 328 PTC patients and validated with 181 slides and RNA sequences from 140 PTC patients in the TCGA cohort. It achieved high accuracy, with an AUC of 0.86 in the training cohort, 0.84 in the validation cohort, and 0.83 in the real-world cohort 2. High-risk patients in the training cohort had significantly lower DFS rates (P<0.001). Model AUCs were 0.91 at 1 year, 0.93 at 3 years, and 0.87 at 5 years. In the validation cohort, high-risk patients also had lower DFS (P<0.001); the AUCs were 0.89, 0.87, and 0.80 at 1, 3, and 5 years. We utilized the GradCAM algorithm to generate heatmaps from pathology-based deep learning models, which visually highlighted high-risk tumor areas in PTC patients. This enhanced clinicians' understanding of the model's predictions and improved diagnostic accuracy, especially in cases with lymph node metastasis. The AI-based analysis uncovered vital insights into PTC molecular heterogeneity, emphasizing BRAF mutations' impact. The integrated deep learning model shows promise in predicting metastasis, offering valuable contributions to improved diagnostic and therapeutic strategies.

Neuroinflammation in Glioblastoma: Progress and Perspectives.

Glioblastoma is the most common and malignant primary brain tumor, with high morbidity and mortality. Despite an aggressive, multimodal treatment regimen, including surgical resection followed by chemotherapy and radiotherapy, the prognosis of glioblastoma patients remains poor. One formidable challenge to advancing glioblastoma therapy is the complexity of the tumor microenvironment. The tumor microenvironment of glioblastoma is a highly dynamic and heterogeneous system that consists of not only cancerous cells but also various resident or infiltrating inflammatory cells. These inflammatory cells not only provide a unique tumor environment for glioblastoma cells to develop and grow but also play important roles in regulating tumor aggressiveness and treatment resistance. Targeting the tumor microenvironment, especially neuroinflammation, has increasingly been recognized as a novel therapeutic approach in glioblastoma. In this review, we discuss the components of the tumor microenvironment in glioblastoma, focusing on neuroinflammation. We discuss the interactions between different tumor microenvironment components as well as their functions in regulating glioblastoma pathogenesis and progression. We will also discuss the anti-tumor microenvironment interventions that can be employed as potential therapeutic targets.

Angiopoietin-Like Protein 2 Expression in Tumor Cells Supports Tumor-Associated Macrophage-Induced Tumor Progression in Esophageal Cancer.

Tumor-associated macrophages(TAM),a major component of the tumor microenvironment, play key roles in tumor formation and progression; however, mechanisms underlying TAM-induced tumor progression are complex and not well known. We previously reported that tumor cell-derived angiopoietin-like protein 2 (ANGPTL2) functions as a tumor promoter in some cancer contexts. We examined ANGPTL2 expression in paraffin-embedded tumor samples from resected specimens of 221 patients with esophageal cancer. Patients were subdivided into four groups based on immunohistochemistry scores described above: ANGPTL2-low/TAM-low, ANGPTL2-low/TAM-high, ANGPTL2-high/TAM-low, and ANGPTL2-high/TAM-high groups. Gene expression datasets of esophageal cancer cell lines were obtained from the cancer cell line encyclopedia public database. In this study, we demonstrate that TAM infiltration is associated with poor prognosis in patients with esophageal cancer whose tumor cells show relatively higher ANGPTL2 expression levels; however, TAM infiltration did not affect prognosis in patients with ANGPTL2-low-expressing esophageal cancer, suggesting that ANGPTL2 expression in esophageal cancer cells is required for TAM-induced tumor progression. Our analysis of public datasets indicates a potential positive correlation of ANGPTL2 expression levels with that of transforming growth factor (TGF)-β, a TAM-activating factor, in esophageal cancer cell lines. We conclude that ANGPTL2 signaling in tumor cells supports TAM-induced tumor progression and contributes to poor prognosis in patients with esophageal cancer. These findings overall provide novel insight into pro-tumor ANGPTL2 functions and illustrate the essential role of cancer cell/TAM crosstalk in cancer progression.

Characterizing the Linkage of Systemic Hypoxia and Angiogenesis in High-Grade Glioma to Define the Changes in Tumor Microenvironment for Predicting Prognosis.

High-grade gliomas (HGG) comprising WHO grades 3 and 4 have a poor overall survival (OS) that has not improved in the past decade. Herein, markers representing four components of the tumor microenvironment (TME) were identified to define their linked expression in TME and predict the prognosis in HGG, namely, interleukin6 (IL6, inflammation), inducible nitric oxide synthase(iNOS), heat shock protein-70 (HSP70, hypoxia), vascular endothelial growth receptor (VEGF), and endothelin1 (ET1) (angiogenesis) and matrix metalloprotease-14 (MMP14) and intercellular adhesion molecule1 (ICAM1, extracellular matrix). To establish a non-invasive panel of biomarkers for precise prognostication in HGG. Eighty-six therapy-naive HGG patients with 45 controls were analyzed for the defined panel. Systemic expression of extracellular/secretory biomarkers was screened dot-immune assay (DIA), quantified by ELISA, and validated by immunocytochemistry (ICC). Expression of iNOS, HSP70, IL-6, VEGF, ET1, MMP14, and ICAM1 was found to be positively associated with grade. Quantification of circulating levels of the markers by ELISA and ICC presented a similar result. The biomarkers were observed to negatively correlate with OS (p < 0.0001). Cox-regression analysis yielded all biomarkers as good prognostic indicators and independent of confounders. On applying combination statistics, the biomarker panel achieved higher sensitivity than single markers to define survival. The intra-association of all seven biomarkers was significant, hinting of a cross-talk between the TME components and a hypoxia driven systemic inflammation upregulating the expression of other components. This is a first ever experimental study of a marker panel that can distinguish between histopathological grades and also delineate differential survival using liquid biopsy, suggesting that markers of hypoxia can be a cornerstone for personalized therapy. The panel of biomarkers of iNOS, HSP70, IL-6, VEGF, ET1, MMP14, and ICAM1 holds promise for prognostication in HGG.

Oncogenic KRAS-dependent stromal interleukin-33 directs the pancreatic microenvironment to promote tumor growth.

Pancreatic cancer is characterized by an extensive fibroinflammatory microenvironment. During carcinogenesis, normal stromal cells are converted to cytokine-high cancer associated fibroblasts (CAFs). The mechanisms underlying this conversion, including regulation and function of fibroblast-derived cytokines, are poorly understood. Thus, efforts to target CAFs therapeutically have so far failed. Here, we show that signals from epithelial cells expressing oncogenic KRAS -a hallmark pancreatic cancer mutation- activate fibroblast autocrine signaling, which drives expression of the cytokine interleukin-33 (IL-33). Stromal IL-33 expression remains high and dependent on epithelial KRAS throughout carcinogenesis; in turn, environmental stress induces IL-33 secretion. Using compartment-specific IL-33 knockout mice, we observed that lack of stromal IL-33 leads to profound reprogramming of multiple components of the pancreatic tumor microenvironment, including CAFs, myeloid cells and lymphocytes. Notably, loss of stromal IL-33 leads to an increase in CD8+ T cell infiltration and activation, and, ultimately, reduced tumor growth.