The Special Issue on high grade serous ovarian cancer (HGSOC) and the contribution of the tumor microenviroment (TME) consists of reviews contributed by leaders in the OC field. As HGSOC metastases ...have a highly complex TME, there is an urgent need to better understand the TME in general, its distinct components in particular, and the role of the TME in the context of disease recurrence and development of chemoresistance. The Special Issue incorporates the current understanding of the different parts of thd TME components, including the cancer cells themselves, the cells surrounding the cancer cells or stromal cells, and the cells of the immune system, which are attracted to the site of metastases. In addition to these cells of the TME, the role of various cellular factors made by the cells of the TME are also the subject of the reviews. In addition, reviews in this Special Issue cover the complex relationships between the molecular mechanisms of HGSOC progression, including genomic, epigenomic and transcriptomic changes and changes in the immune cell landscape, as these may provide attractive new molecular targets for HGSOC therapy.
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•TNBC is highly challenging subtype of breast cancer due to unique tumor microenvironment (TME).•TME associates with aggressive nature, metastasis and drug resistance in ...TNBC.•Epigenetic based regulations within TME drive carcinogenesis.•Novel therapeutic targets of TME helps in early diagnosis and effective treatment of TNBC.
Triple negative breast cancer (TNBC) is most aggressive subtype of breast cancers with high probability of metastasis as well as lack of specific targets and targeted therapeutics. TNBC is characterized with unique tumor microenvironment (TME), which differs from other subtypes. TME is associated with induction of proliferation, angiogenesis, inhibition of apoptosis and immune system suppression, and drug resistance. Exosomes are promising nanovesicles, which orchestrate the TME by communicating with different cells within TME. The components of TME including transformed ECM, soluble factors, immune suppressive cells, epigenetic modifications and re-programmed fibroblasts together hamper antitumor response and helps progression and metastasis of TNBCs. Therefore, TME could be a therapeutic target of TNBC. The current review presents latest updates on the role of exosomes in modulation of TME, approaches for targeting TME and combination of immune checkpoint inhibitors and target chemotherapeutics. Finally, we also discussed various phytochemicals that alter genetic, transcriptomic and proteomic profiles of TME along with current challenges and future implications. Thus, as TME is associated with the hallmarks of TNBC, the understanding of the impact of different components can improve the clinical benefits of TNBC patients.
Catalytic cancer therapy based on nanozymes has recently attracted much interest. However, the types of the current nanozymes are limited and their efficiency is usually compromised and not ...sustainable in the tumor microenvironment (TME). Therefore, combination therapy involving additional therapeutics is often necessary and the resulting complication may jeopardize the practical feasibility. Herein, an unprecedented "all-in-one" Fe
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nanoparticle (FAB NP) is rationally devised to achieve synergistic chemodynamic, photodynamic, photothermal therapy with guidance by magnetic resonance, photoacoustic, and photothermal imaging. Based on its manifold nanozyme activities (mimicking peroxidase, catalase, superoxide dismutase, glutathione oxidase) and photodynamic property, cascaded nanocatalytic reactions are enabled and sustained in TME for outstanding therapeutic outcomes. The working mechanisms underlying the intraparticulate interactions, sustainability, and self-replenishment arising from the coupling between the nanocatalytic reactions and nanozyme activities are carefully revealed, providing new insights into the design of novel nanozymes for nanocatalytic therapy with high efficiency, good specificity, and low side effects.
Abstract
The effects of tumor-associated neutrophils (TANs) on glioblastoma biology remain poorly understood. Flow cytometric analysis of 5 newly diagnosed glioblastoma fresh tissue specimens ...surprisingly revealed a high fraction (21.0-34.1%) of TANs expressed MHCII, a marker of antigen-presenting cells not classically associated with neutrophils and not expressed in matched peripheral blood (PBNs). Transcriptomic profiling confirmed that patient TANs upregulated expression of MHCII subunits (HLA-DR), chaperones (HLA-DM), and costimulatory ligands (CD86/83). Ex vivo cocultures further demonstrated that TANs activated patient-matched naïve T cells in an MHCII-dependent manner, while PBNs did not (CD25 MFI fold-change: 1.1 vs 3.2, p< 0.001). The antitumoral relevance of this property was confirmed in a syngeneic mouse glioma model, wherein αLy6G-mediated neutrophil depletion in T-cell-competent mice (Balb/c, n= 13) yielded endpoint tumors that had reduced CD8+ T cell infiltration (p= 0.0024) and were 2.4-fold larger by BLI (p= 0.0383) than controls, but had no bearing on tumor burden in T-cell-deficient (athymic) mice. Given the absence of MHCII+ neutrophils in circulation, we interrogated the inducibility of this phenotype by tumor-conditioned media in murine marrow/blood, finding that only immature Ly6Glow bone marrow neutrophils had sufficient plasticity to express MHCII and process foreign antigen as measured by DQ-ovalbumin uptake/proteolysis. Because of the non-inducibility of PBNs, we investigated the hypothesis that MHCII+ TANs were recruited to the glioblastoma microenvironment from adjacent skull bone marrow by labeling this space with CFMDA in tumor-implanted mice; at 72h, skull marrow-derived neutrophils contributed disproportionately to MHCII+ TANs compared to all TANs (41.7% vs 9.3%). As confirmation, in the first-ever scRNA-seq of human TANs, we demonstrated via pseudotime analysis that MHCII+ neutrophils represent a developmental lineage seen in TANs but not matched PBNs. Given the immunostimulatory effects of this population, mechanisms to promote neutrophil egress and tumor infiltration from the skull marrow may have therapeutic value.
Abstract
Cellular senescence (CS) is a state of irreversible cell cycle arrest, and the expression of p16INK4a in cells is one of the reliable markers for CS. However, senescent cells are ...metabolically active with the senescence-associated secretory phenotype (SASP), which can influence the tissue microenvironment by paracrine signaling to the adjacent tumor, non-tumor, and immune cells. In the present study, we evaluated p16INK4a expression in glioblastoma and investigated its association with CS and SASPs. We analyzed the expression of p16INK4a in 73 glioblastomas by immunostaining. To examine the association of p16INK4a expression and CS, we performed senescence-associated β-galactosidase (SA-β-Gal) staining, a standard marker of CS, using glioblastoma cell lines and fresh frozen tumor tissues. For SASPs analysis, RNA sequencing with Gene Set Enrichment Analysis (GSEA) was performed. Among 73 glioblastomas, twenty-eight cases (38.4%) revealed diffuse strong p16INK4a expression in tumor cells. The glioblastoma with diffuse p16INK4a expression (GMDP) patients were younger (52.4 vs. 59.2 years) and showed prolonged overall survival (median: 25.5 vs. 12.3 months) compared to those harboring negative expression. In vitro analysis, p16INK4a over-expressed glioblastoma cell line showed increased expression of SA-β-Gal which indicates CS. In addition, fresh frozen tissues from GMDP also revealed SA-β-Gal positivity. RNA sequencing analysis revealed that splicing or protein biosynthetic genes were enriched in GMDP, and GSEA showed significant enrichment of SASP genes (false discovery rate < 0.05), especially chemokines associated with monocytes and macrophages. Our data suggest that increased expression of p16INK4a in glioblastoma is associated with tumor cell senescence, and SASPs from senescent tumor cells could be one of the crucial modulators in the tumor immune microenvironment.
Abstract
Glioblastoma (GBM) is the most common and aggressive primary brain tumor with a median survival of only 15 months and a 5-year survival of less than 5% despite the best available treatments. ...Tumor recurrence/progression and therapy resistance are major obstacles for GBM treatment. GBM is characterized by intensive vascular proliferation that is associated with tumor cell growth, invasion, resistance to chemo/radiotherapy, and decreased disease-free survival. Increasing data have shown the existence of cells with endothelial characteristics called tumor derived endothelial cells, which come from the transdifferentiation of GBM cells and, more specifically, from GBM stem cells (GSCs). However, the molecular mechanisms underlying this process remain largely unknown. GSCs are tightly regulated by distinct transcriptional programs that are driven by nuclear transcription factors. Brachyury is a transcription factor expressed in normal, undifferentiated embryonic notochord in the axial skeleton and plays an important role in stem cell development and differentiation during normal embryonic development. Here, we show that brachyury is highly expressed in patient-derived GBM cells. Functional studies demonstrate that brachyury is regulated by fibroblast growth factor receptor 1 (FGFR1)/mitogen-activated protein kinase (MAPK). Our studies further disclose that FGFR1/MAPK-directed brachyury activation promotes GSC survival and endothelial formation via vascular endothelial growth factor receptor 2 (VEGFR2), whereas pharmacological inhibition of FGFR1 and MAPK or shRNA-mediated downregulation of brachyury decreases GSC transdifferentiation into endothelial cells and suppresses GBM cell growth and stemness via VEGFR2. Our findings highlight the importance of FGFR1/MAPK-regulated brachyury activation in GSC transdifferentiation into endothelial cells via VEGFR2, and targeting the FGFR1-MAPK-brachyury-VEGFR2 signal pathway may represent a novel therapeutic strategy by reprogramming GSCs driving vascular transdifferentiation and tumor progression.
Abstract
Regional diversity of anti-tumor immunity in glioblastoma (GBM) has been poorly investigated due to technical limitations. To overcome these hurdles, we developed SPTCR-seq (SPatial TCell ...Receptor sequencing) to spatially profile T cell immune response. Here, we performed 10X-Visium spatial transcriptomics and SPTCR-seq on 9 de-novo IDH wt glioblastoma. For SPTCR-seq, we captured enriched T-cell receptor (TCR) sequences by hybridization followed by Oxford nanopore (ONT) long-read sequencing. We established a computational pipeline for spatial demultiplexing, error correction and TCR reconstruction using a Seq2Vector model, followed by a long-term memory autoencoder to deconvolute and compare CDR3 sequence similarities across patients. The on-target rate for detected TCR genes reached over 85%, of which our long-TCR algorithm could completely reconstruct TCRs in over 70%. To decipher the regional diversity of T-cell clonality, we performed spatially weighted regression to estimate the overlap of T-cell clonal expansion to the recently described regional transcriptional niches. We found that myeloid cell infiltration was highly correlated with increased T cell diversity. We integrated single cell RNA-seq data and annotated T cell subtypes through the “natural barcode” of the CDR3 sequence, revealing that CD4+ T cells interact with myeloid cells via MHCII in segregated areas, also described as the Reactive Immune niche. In contrast, CD8+ T cells exhibit a dysfunctional/exhausted phenotype at the same location. In comparison to the myeloid-infiltrated regions, the hypoxia-associated niches showed increased CD8+ T cells with greater clonal expansion, suggesting an immune response anti-cancer immunity. Global spatial vector field analysis revealed a spatial co-occurrence of metabolic vulnerability and a mutational burden with CD8+ T effector cells negatively associated with myeloid cell infiltration. Integration of CDR3 sequences in different patients revealed higher similarity of motifs of CD4+ compared with CD8+ T cells in hypoxia areas. Our data provide new insights into the regional heterogeneity of cancer immunity.
Abstract
INTRODUCTION
Patients with glioblastoma have a very poor prognosis. Tumor-associated microglia and macrophages (TAMs) constitute up to 30 % of the cells in glioblastoma, and they secrete ...cytokines, chemokines and growth factors that influence the microenvironment. The existence of different TAM subtypes appears to be more complex than the established M1 and M2 phenotypes, but their role in glioblastoma is not fully understood and rarely considered therapeutically. This could explain why many clinical trials fail despite of promising preclinical results. This project aims to interrogate the existence and characteristics of different TAM subtypes in human glioblastoma in order to identify novel subpopulations and therapeutic targets. MATERIALS AND
METHODS
Live CD11b+ TAMs were isolated from patient glioblastoma tissue, and single-cell RNA sequencing (scRNA-seq) was performed using the 10X Genomics Chromium platform. The data was processed and analyzed with the R-package Seurat.
RESULTS
We have sequenced 74,000 TAMs/microglia from three glioblastomas and two control brain biopsies. In the controls, we detected mostly microglia, while the primary glioblastomas showed a predominance of monocyte-derived TAMs. We identified 11 TAM subtypes, such as hypoxic, proliferating, interferon-induced, chemokine-producing and TNF-producing TAMs, as well as a novel subtype potentially involved in tumor progression.
CONCLUSION AND PERSPECTIVES
We have detected a spectrum of TAM subtypes, which is more complex than the established M1 and M2 phenotypes. Our findings confirm a recent TAM scRNA-seq study, and in addition, we identify a novel subpopulation, which express known tumor-promoting genes, normally expressed by cancer cells. We are currently validating our findings. This study contributes to the elucidation of the glioblastoma microenvironment. It will potentially lead to identification of novel clinically relevant targets affecting the TAM-glioblastoma interactions.
Abstract
Whereas evidences of single-cell studies have suggested the cellular diversity of medulloblastoma, the most common malignant brain tumor in childhood, the understanding of spatial status for ...specific cell populations and gene modules remains rudimentary. Herein, we comprehensively analyze single-nucleus RNA expression, chromatin accessibility and spatial transcriptomic profiling from 52 human medulloblastomas spanning four molecular subgroups, complemented with the bulk whole genome and RNA sequencing data across 300 samples. We comprehensively interrogated the composition of medulloblastoma microenvironment and spatially described the developmental trajectory from progenitor-like to differentiated malignant cells. Furthermore, distinct heterogeneity within molecular subgroups leads to the identification of twelve subtypes of medulloblastoma, which unfortunately lacks the cellular biology. By deciphering the copy number variation and transcriptional programs at single-cell resolution, we in-depth characterized medulloblastoma and mapped the activity of gene expression and transcription factor binding according to individual subtype. The WNT-β, SHH-γ, Group 3-β and Group 4-γ were observed in early differentiation stage. Harmony alignment revealed subtype-dependent modules recapitulated the neurodevelopmental gene enrichment, strongly correlating to clinical outcomes. Collectively, our findings provide spatiotemporally resolved insights into transcriptome and epigenome of twelve-subtype medulloblastoma allowing further refinement regarding clinical risk stratification strategies.
Abstract
Tumor associated microglia and macrophages (TAMs) represent a main cell type of brain malignancies and demonstrate complex interactions with cancerous cells and the tumor microenvironment. ...These interactions have important implications for the progression and treatment of malignant central nervous system (CNS) tumors. In a non-oncological context, it has been shown that endogenous microglia can be replaced by peripheral hematopoietic cells by genetic or pharmacological intervention. A highly efficient replacement protocol (Shibuya et al, Sci Transl Med 2022, PMID:35294256) utilizing myeloablative bone marrow transplantation (BMT) followed by microglial depletion via pharmacological inhibition of the Colony-stimulating factor-1 receptor (CSF-1R) leads to almost complete repopulation of the CNS myeloid niche by circulation-derived myeloid cells (CDMCs). We investigated if this approach could be utilized to integrate CDMCs into brain tumors and study associated changes in the TAM signature. Microglia replacement in immune-competent mice was followed by intracranial transplantation of syngeneic cell lines of either high-grade glioma (GL261) or breast cancer metastasis (E0771). Lineage tracing proved high intra- and peri-tumoral chimerism of BMT-graft derived cells among CNS myeloid cells in both models two weeks after tumor cell injection. Tumor associated CDMCs (TA-CDMCs) showed a similarly activated morphology as naïve TAMs. We used single cell RNA sequencing of CD45-positive cells to further profile the transcriptomic identity of glioma TA-CDMCs. Pathway enrichment analysis revealed an upregulation of immune response pathways in TA-CDMCs compared to regular TAMs, including the overexpression of genes relevant for the regulation of T cell activation, suggesting possible modification of the glioma immune-environment. Strategies to manipulate the myeloid niche have the potential to provide further understanding of the pathobiology of TAMs and to build the basis for novel cell therapeutic approaches in the neuro-oncological domain.
