scholarly journals OTME-2. Regulation of chromatin accessibility in the hypoxic tumor microenvironment of glioblastoma

2021 ◽  
Vol 3 (Supplement_2) ◽  
pp. ii13-ii13
Author(s):  
Monika Dzwigonska ◽  
Jakub Mieczkowski ◽  
Paulina Pilanc ◽  
Salwador Cyranowski ◽  
Agata Kominek ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Single Cells ◽  
Glioma Cells ◽  
Therapy Resistance ◽  
Chromatin Accessibility ◽  
Protein Markers ◽  
Science Center ◽  
Regulation Of Expression ◽  
Genome Wide

Abstract Chromatin structure is often dysregulated in cancers, including glioblastoma (GBM), the most common primary brain tumor in adults. GBM has the poorest prognosis and no efficient cure to date due to diffusive growth into the surrounding brain, preventing complete surgical resection and leading to inevitable tumor relapse. Tumor microenvironment (TME) of GBM contains brain-residing microglia and bone-marrow derived macrophages (collectively known as glioma-associated microglia/macrophages, GAMs) that constitute up to 30% of the tumor mass and promote tumor invasion. Hypoxia (a shortage of oxygen) is a key factor in tumor progression of GBM as it can globally and rapidly alter the gene expression, induce cancer cell invasiveness, stemness and lead to therapy resistance. Hypoxia can enhance the pro-tumorigenic function of GAMs, e.g. by inducing expression of cytokines and cell surface receptors both in GAMs and glioma cells, but little is known about chromatin alterations of GBM under hypoxia. Since regulation of expression of such molecules could depend on the epigenetic alterations, we hypothesize that hypoxia may potently alter the chromatin accessibility and functions of GAMs and glioma cells. We determine the genome-wide changes in chromatin accessibility in GAMs and glioma cells in response to hypoxic stress using single-cell Pi-ATAC-seq (Protein-indexed Assay of Transposase Accessible Chromatin with sequencing), which allows simultaneous genome-wide assessment of chromatin accessibility and expression of intracellular protein markers in single cells, allowing faithful selection of hypoxic and non-hypoxic cells. Secondly, we are employing an oxygen-dependent co-culture model in vitro to study the mechanisms of chromatin alterations in GAMs and glioma cells under controlled hypoxic conditions and test how these changes depend on the glioma - GAMs cross-communication. In summary, we characterize the interactions between innate immune cells and glioma cells by looking at their chromatin alterations under hypoxia. Supported by the National Science Center grant (Poland) 2019/33/B/NZ1/01556 (KBL).

P16.09 Regulation of chromatin accessibility in the hypoxic tumor microenvironment of glioblastoma

2021 ◽  
Vol 23 (Supplement_2) ◽  
pp. ii57-ii57
Author(s):  
M Dzwigonska ◽  
J Mieczkowski ◽  
P Pilanc ◽  
S Cyranowski ◽  
A Kominek ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Single Cell ◽  
Cancer Cells ◽  
Single Cells ◽  
Therapy Resistance ◽  
Chromatin Accessibility ◽  
Open Chromatin ◽  
Dependent Manner ◽  
Protein Markers ◽  
Hypoxic Tumor

Abstract BACKGROUND Chromatin structure is often dysregulated in cancers, including glioblastoma (GBM), the most aggressive type of primary brain tumor. GBM has the poorest prognosis with no efficient cure to date due to diffusive growth into the brain, resistance to treatments and the immunosuppressive tumor microenvironment (TME). The growth and invasiveness of GBM is supported by the heterogeneous TME including local microglia and bone-marrow-derived macrophages (collectively known as glioma-associated microglia and macrophages, GAMs). In addition, tumor hypoxia is a key factor in the progression of GBM, as it can globally and rapidly alter gene expression, induce cancer cell invasiveness, stemness and lead to therapy resistance. Hypoxia can influence the pro-tumorigenic function of GAMs by inducing the expression of cytokines and cell surface receptors. However, little is known on the hypoxia-imposed chromatin changes of GAMs and GBM cells, which can in turn impact the interaction between these cell populations. Here we analyze these changes using a single-cell method, which preserves in situ hypoxia within the TME of GBM. MATERIAL AND METHODS Single-cell Pi-ATAC-seq (Protein-indexed Assay of Transposase Accessible Chromatin with sequencing) method in a GL261 murine glioma model was used to simultaneously assess genome-wide chromatin accessibility and expression of intracellular protein markers in single cells, enabling accurate selection of hypoxic and non-hypoxic tumor cells and GAMs. Pi-ATAC-seq is used on paraformaldehyde-perfused tumors and therefore allows capturing unaltered hypoxia-dependent cellular states, that often become distorted during dissociation and preparation of fresh material in most common single-cell methods. RESULTS We optimized Pi-ATAC method in a GL261 GBM mouse model, with specific sorting of GAMs using CD11b+ immunosorting followed by separation of microglia and macrophages, based on intensity of CD45 staining. HIF-1α induction and binding of pimonidazole were used to mark hypoxic populations. Currently, we are investigating the chromatin accessibility profiles of cancer cells and GAMs within the hypoxic tumor microenvironment of GBM. Exploring open chromatin profiles in GAMs and glioma-microglia co-cultures will allow to unravel the mechanisms of chromatin accessibility modulation in the oxygen-dependent manner. CONCLUSION In summary, we optimized the Pi-ATAC method in a mouse GBM model to characterize the chromatin openness changes in GAMs and cancer cells in response to hypoxic stress. Further validation of these results will provide the potential to identify novel markers for GAMs/glioma interactions in hypoxic GBMs and develop novel therapeutic targets.

scholarly journals Genome-wide CRISPR-Cas9 screen identified KLF11 as a druggable suppressor for sarcoma cancer stem cells

2021 ◽  
Vol 7 (5) ◽  
pp. eabe3445
Author(s):  
Yicun Wang ◽  
Jinhui Wu ◽  
Hui Chen ◽  
Yang Yang ◽  
Chengwu Xiao ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cancer Stem Cells ◽  
Negative Feedback ◽  
Direct Interaction ◽  
Therapy Resistance ◽  
Negative Regulator ◽  
Chemotherapy Response ◽  
Genome Wide

Cancer stem cells (CSCs) are involved in tumorigenesis, recurrence, and therapy resistance. To identify critical regulators of sarcoma CSCs, we performed a reporter-based genome-wide CRISPR-Cas9 screen and uncovered Kruppel-like factor 11 (KLF11) as top candidate. In vitro and in vivo functional annotation defined a negative role of KLF11 in CSCs. Mechanistically, KLF11 and YAP/TEAD bound to adjacent DNA sites along with direct interaction. KLF11 recruited SIN3A/HDAC to suppress the transcriptional output of YAP/TEAD, which, in turn, promoted KLF11 transcription, forming a negative feedback loop. However, in CSCs, this negative feedback was lost because of epigenetic silence of KLF11, causing sustained YAP activation. Low KLF11 was associated with poor prognosis and chemotherapy response in patients with sarcoma. Pharmacological activation of KLF11 by thiazolidinedione effectively restored chemotherapy response. Collectively, our study identifies KLF11 as a negative regulator in sarcoma CSCs and potential therapeutic target.

Interfering With Hyaluronic Acid Metabolism Suppresses Glioma Cell Proliferation by Regulating Autophagy

2020 ◽  
Author(s):  
Tao Yan ◽  
Xin Chen ◽  
Hua Zhan ◽  
Penglei Yao ◽  
Ning Wang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Hyaluronic Acid ◽  
Tumor Microenvironment ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Glioma Cell ◽  
Glioma Cells

Abstract BackgroundThe tumor microenvironment plays an important role in tumor progression. Hyaluronic acid (HA), an important component of the extracellular matrix in the tumor microenvironment, abnormally accumulates in a variety of tumors. Whereas the role of abnormal HA metabolism in glioma remains unclear. MethodsThe expression level of hyaluronic acid (HA) was analyzed by ELISA assay and proteins such as HAS3, CD44, P62, LC3, CCND1 and CCNB1 were measured with Western blot analysis. The cell viability and proliferation were measured by MTT and KI67 immunofluorescence staining respectively. Autophagic vesicles and autophagosomes were quantified by transmission electron microscopy (TEM) and GFP-RFP-LC3 fluorescence analysis respectively. Cell cycle was analyzed by flowcytometry and Western blot analysis. Immunohistochemical (IHC) staining was used to detect expression levels of HA, Ki67, HAS3 and CD44 in human and mouse tumor tissues. Lentivirus constructed HAS3 and CD44 knockout stable glioma cells were transplanted to BALB/C nude mice for in vivo experiments. 4-Methylumbelliferone (4MU) was also used to treat glioma bearing mice for verifing its anti-tumor ability. The expression curve of HAS3, CD44 and the disease-free survival (DFS) curves for HAS3, CD44 in patients with LGG and GBM was performed based on TCGA database. ResultsAs shown in the present study, HA, hyaluronic acid synthase 3 (HAS3) and a receptor of HA named CD44 are expressed at high levels in human glioma tissues and negatively correlated with the prognosis of patients with glioma. Silencing HAS3 or blocking CD44 inhibited the proliferation of glioma cells in vitro and in vivo. The underlying mechanism was attributed to the inhibition of autophagy flux and further maintaining glioma cell cycle arrest in G1 phase. More importantly, 4-Methylumbelliferone (4-MU), a small competitive inhibitor of UDP with the ability to penetrate the blood-brain barrier (BBB), also inhibited the proliferation of glioma cells in vitro and in vivo. ConclusionApproaches that interfere with HA metabolism by altering the expression of HAS3 and CD44 and the administration of 4-MU potentially represent effective strategies for glioma treatment.

scholarly journals EPIG-06ATRX DEFICIENCY PROMOTES MIGRATORY BEHAVIOR IN GLIOMA CELLS OF ORIGIN BY DYSREGULATING GENOME-WIDE CHROMATIN ACCESSIBILITY AND MODULATING TRANSCRIPTIONAL PROGRAMS

2015 ◽  
Vol 17 (suppl 5) ◽  
pp. v87.2-v87
Author(s):  
Carla Danussi ◽  
Promita Bose ◽  
Prasanna Parthasarathy ◽  
Sevin Turcan ◽  
David Picketts ◽  
...  
Keyword(s):  
Glioma Cells ◽  
Chromatin Accessibility ◽  
Migratory Behavior ◽  
Genome Wide ◽  
Cells Of Origin

scholarly journals TSPO imaging-guided characterization of the immunosuppressive myeloid tumor microenvironment in patients with malignant glioma

2020 ◽  
Vol 22 (7) ◽  
pp. 1030-1043 ◽  
Author(s):  
Bastian Zinnhardt ◽  
Michael Müther ◽  
Wolfgang Roll ◽  
Philipp Backhaus ◽  
Astrid Jeibmann ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Suppressor Cells ◽  
Human Leukocyte ◽  
Strong Relationship ◽  
Therapy Resistance ◽  
Translocator Protein ◽  
Image Guided ◽  
Hla Dr

Abstract Background Tumor-associated microglia and macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) are potent immunosuppressors in the glioma tumor microenvironment (TME). Their infiltration is associated with tumor grade, progression, and therapy resistance. Specific tools for image-guided analysis of spatiotemporal changes in the immunosuppressive myeloid tumor compartments are missing. We aimed (i) to evaluate the role of fluorodeoxyglucose (18F)DPA-714* (translocator protein [TSPO]) PET-MRI in the assessment of the immunosuppressive TME in glioma patients, and (ii) to cross-correlate imaging findings with in-depth immunophenotyping. Methods To characterize the glioma TME, a mixed collective of 9 glioma patients underwent [18F]DPA-714-PET-MRI in addition to [18F]fluoro-ethyl-tyrosine (FET)-PET-MRI. Image-guided biopsy samples were immunophenotyped by multiparametric flow cytometry and immunohistochemistry. In vitro autoradiography was performed for image validation and assessment of tracer binding specificity. Results We found a strong relationship (r = 0.84, P = 0.009) between the [18F]DPA-714 uptake and the number and activation level of glioma-associated myeloid cells (GAMs). TSPO expression was mainly restricted to human leukocyte antigen D related–positive (HLA-DR+) activated GAMs, particularly to tumor-infiltrating HLA-DR+ MDSCs and TAMs. [18F]DPA-714–positive tissue volumes exceeded [18F]FET-positive volumes and showed a differential spatial distribution. Conclusion [18F]DPA-714-PET may be used to non-invasively image the glioma-associated immunosuppressive TME in vivo. This imaging paradigm may also help to characterize the heterogeneity of the glioma TME with respect to the degree of myeloid cell infiltration at various disease stages. [18F]DPA-714 may also facilitate the development of new image-guided therapies targeting the myeloid-derived TME.

scholarly journals TAMI-47. EVALUATION OF THE EFFECT OF MICROENVIRONMENTAL STRESSES ON GLIOMA STEMNESS IN VITRO AND EX VIVO

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii223-ii223
Author(s):  
Vasiliki Pantazopoulou ◽  
Tracy Berg ◽  
Alexander Pietras
Keyword(s):  
Tumor Microenvironment ◽  
Stromal Cells ◽  
Ex Vivo ◽  
Morphological Changes ◽  
Side Population ◽  
Therapy Resistance ◽  
Cell Phenotype ◽  
Vimentin Expression ◽  
Perivascular Niche

Abstract Glioblastoma is the highest-grade glioma and most aggressive brain tumor, affecting both adults and children. Treatment includes surgery followed by chemotherapy, most frequently in the form of temozolomide treatment, radiation and in some cases by application of tumor-treating fields. Tumor recurrence is very common and is driven by cells exhibiting a treatment-resistant cancer stem cell phenotype, located in specific niches, namely the hypoxic and perivascular niche. While previous studies have delved into the role of the microenvironment in supporting glioma stemness and therapy resistance, little is known about how the stromal cells themselves respond to microenvironmental stresses. Here, we show that one cell type of the tumor microenvironment, the astrocyte, becomes activated after treatment with radiation, temozolomide or hypoxia in vitro, showing an increase in GFAP and Vimentin expression as well as morphological changes. Activated astrocytes also change their secretome, secreting cytokines such as IL6, IL7, CCL2 and CCL8, all associated with worse prognosis in several patient cohorts. Importantly, conditioned medium or extracellular matrix from activated astrocytes induce stemness features in glioma cells, measured by increased side population or radiation resistant fractions. To evaluate our findings in a more relevant model, we use an ex vivo organotypic culture system for brain sections from our experimental mouse model of glioma. Cultures are maintained for up to 21 days in 21%, 5% or 1% O2 with a high proportion of surviving tumor and stromal cells. We intend to use the ex vivo system to evaluate the effect of microenvironmental stresses on glioma stemness. Our study suggests that the tumor microenvironment that has been exposed to stressors such as radiation, chemotherapy or hypoxia is important in maintaining stemness and therefore treatment resistance in glioblastoma. Further research is required to address these stress-induced changes and provide better treatment options for glioblastoma patients.

scholarly journals TMIC-20. ELIMINATION OF SENESCENT ASTROCYTES IN THE BRAIN TUMOR MICROENVIRONMENT ATTENUATES GLIOBLASTOMA RECURRENCE AFTER RADIOTHERAPY

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi251-vi251
Author(s):  
Eliot Fletcher-Sananikone ◽  
Bipasha Mukherjee ◽  
Sandeep Burma
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Neutralizing Antibodies ◽  
Glioma Cells ◽  
Cell Types ◽  
Normal Brain ◽  
High Doses

Abstract Glioblastomas (GBM) are treated with high doses of ionizing radiation (IR) yet these tumors inevitably recur, and the recurrent tumors are highly therapy resistant. During GBM therapy, the surrounding brain tissue is irradiated along with the tumor. IR induces senescence in multiple cell types, and senescent stromal cells are known to promote the growth of neighboring tumor cells by secreting cytokines which create a senescence-associated secretory phenotype (SASP). We hypothesize that IR-induced senescence of normal brain cells in the tumor microenvironment is a powerful driver of GBM recurrence. We intra-cranially irradiated C57BL/6J mice, and found evidence of widespread senescence, with the astrocytic population being highly susceptible. Genomic analyses of irradiated brains revealed an altered transcriptomic profile which included upregulation of CDKN1A (p21), a key enforcer of senescence, and increased expression of SASP proteins including HGF, the ligand for the RTK Met. We orthotopically implanted mock-irradiated or irradiated mice with a limiting number of syngeneic glioma cells. Pre-irradiation of mouse brains resulted in a striking increase in tumor growth and invasion driven by Met activation in the tumor cells. Importantly, irradiated p21-/- mouse brains did not exhibit SASP and failed to promote tumor growth. Irradiated primary astrocytes underwent senescence in vitro and promoted the migration of glioma cells, and this could be attenuated with HGF-neutralizing antibodies or by the Met inhibitor Crizotinib. These findings indicate that SASP factors (like HGF) in the irradiated brain microenvironment could drive GBM recurrence after radiotherapy via the activation of RTKs (like MET) in the tumor cells. Significantly, we found that senolytic drugs can selectively kill senescent astrocytes both in vitro and in vivo resulting in attenuated growth of glioma cells. These results are of great translational significance as they indicate that adjuvant therapy with senolytic drugs might attenuate GBM recurrence after radiotherapy.

scholarly journals HOXA1 Is an Antagonist of ERα in Breast Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Magali Belpaire ◽  
Bruno Ewbank ◽  
Arnaud Taminiau ◽  
Laure Bridoux ◽  
Noémie Deneyer ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Dna Binding ◽  
Expression Profiles ◽  
Therapy Resistance ◽  
Breast Cancers ◽  
Hox Proteins ◽  
Genome Wide ◽  
Functional Antagonism ◽  
Public Datasets

Breast cancer is a heterogeneous disease and the leading cause of female cancer mortality worldwide. About 70% of breast cancers express ERα. HOX proteins are master regulators of embryo development which have emerged as being important players in oncogenesis. HOXA1 is one of them. Here, we present bioinformatic analyses of genome-wide mRNA expression profiles available in large public datasets of human breast cancer samples. We reveal an extremely strong opposite correlation between HOXA1 versus ER expression and that of 2,486 genes, thereby supporting a functional antagonism between HOXA1 and ERα. We also demonstrate in vitro that HOXA1 can inhibit ERα activity. This inhibition is at least bimodal, requiring an intact HOXA1 DNA-binding homeodomain and involving the DNA-binding independent capacity of HOXA1 to activate NF-κB. We provide evidence that the HOXA1-PBX interaction known to be critical for the transcriptional activity of HOXA1 is not involved in the ERα inhibition. Finally, we reveal that HOXA1 and ERα can physically interact but that this interaction is not essential for the HOXA1-mediated inhibition of ERα. Like other HOX oncoproteins interacting with ERα, HOXA1 could be involved in endocrine therapy resistance.

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