Inhibition of vasculogenesis, but not angiogenesis, prevents the recurrence of glioblastoma after irradiation in mice.
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ABSTRACT:
SUBMITTER: Kioi M
PROVIDER: S-EPMC2827954 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundResidual disease of glioblastoma (GBM) causes recurrence. However, targeting residual cells has failed, due to their inaccessibility and our lack of understanding of their survival mechanisms to radiation therapy. Here we deciphered a residual cell-specific survival mechanism essential for GBM relapse.MethodsTherapy resistant residual (RR) cells were captured from primary patient samples and cell line models mimicking clinical scenario of radiation resistance. Molecular signaling of resistance in RR cells was identified using RNA sequencing, genetic and pharmacological perturbations, overexpression systems, and molecular and biochemical assays. Findings were validated in patient samples and an orthotopic mouse model.ResultsRR cells form more aggressive tumors than the parental cells in an orthotopic mouse model. Upon radiation-induced damage, RR cells preferentially activated a nonhomologous end joining (NHEJ) repair pathway, upregulating Ku80 and Artemis while downregulating meiotic recombination 11 (Mre11) at protein but not RNA levels. Mechanistically, RR cells upregulate the Su(var)3-9/enhancer-of-zeste/trithorax (SET) domain and mariner transposase fusion gene (SETMAR), mediating high levels of H3K36me2 and global euchromatization. High H3K36me2 leads to efficiently recruiting NHEJ proteins. Conditional knockdown of SETMAR in RR cells induced irreversible senescence partly mediated by reduced H3K36me2. RR cells expressing mutant H3K36A could not retain Ku80 at double-strand breaks, thus compromising NHEJ repair, leading to apoptosis and abrogation of tumorigenicity in vitro and in vivo. Pharmacological inhibition of the NHEJ pathway phenocopied H3K36 mutation effect, confirming dependency of RR cells on the NHEJ pathway for their survival.ConclusionsWe demonstrate that the SETMAR-NHEJ regulatory axis is essential for the survival of clinically relevant radiation RR cells, abrogation of which prevents recurrence in GBM.
| S-EPMC7746947 | biostudies-literature
Project description:Transcription factors (TFs) play a crucial role in regulating the dynamic and precise patterns of gene expression required for the initial specification of endothelial cells (ECs), and during endothelial growth and differentiation. While sharing many core features, ECs can be highly heterogeneous. Differential gene expression between ECs is essential to pattern the hierarchical vascular network into arteries, veins and capillaries, to drive angiogenic growth of new vessels, and to direct specialization in response to local signals. Unlike many other cell types, ECs have no single master regulator, instead relying on differing combinations of a necessarily limited repertoire of TFs to achieve tight spatial and temporal activation and repression of gene expression. Here, we will discuss the cohort of TFs known to be involved in directing gene expression during different stages of mammalian vasculogenesis and angiogenesis, with a primary focus on development.
| S-EPMC10952167 | biostudies-literature
Project description:The process of new blood vessel formation is critical in tissue development, remodeling and regeneration. Modular tissue engineering approaches have been developed to enable the bottom-up assembly of more complex tissues, including vascular networks. In this study, collagen-fibrin composite microbeads (100-300 ?m in diameter) were fabricated using a water-in-oil emulsion technique. Human endothelial cells and human fibroblasts were embedded directly in the microbead matrix at the time of fabrication. Microbead populations were characterized and cultured for 14 days either as free-floating populations or embedded in a surrounding fibrin gel. The collagen-fibrin matrix efficiently entrapped cells and supported their viability and spreading. By 7 days in culture, endothelial cell networks were evident within microbeads, and these structures became more prominent by day 14. Fibroblasts co-localized with endothelial cells, suggesting a pericyte-like function, and laminin deposition indicated maturation of the vessel networks over time. Microbeads embedded in a fibrin gel immediately after fabrication showed the emergence of cells and the coalescence of vessel structures in the surrounding matrix by day 7. By day 14, inosculation of neighboring cords and prominent vessel structures were observed. Microbeads pre-cultured for 7 days prior to embedding in fibrin gave rise to vessel networks that emanated radially from the microbead by day 7, and developed into connected networks by day 14. Lumen formation in endothelial cell networks was confirmed using confocal sectioning. These data show that collagen-fibrin composite microbeads support vascular network formation. Microbeads embedded directly after fabrication emulated the process of vasculogenesis, while the branching and joining of vessels from pre-cultured microbeads resembled angiogenesis. This modular microtissue system has utility in studying the processes involved in new vessel formation, and may be developed into a therapy for the treatment of ischemic conditions.
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Project description:Scleroderma (SSc) is a complex disease that involves activation of the immune system, vascular complications, and tissue fibrosis. The histone methyltransferase enhancer of zeste homolog 2 (EZH2) mediates trimethylation of lysine 27 of histone 3 (H3K27me3), which acts as a repressive epigenetic mark. Both EZH2 and H3K27me3 were elevated in SSc dermal fibroblasts and endothelial cells compared with healthy controls. EZH2 inhibitor DZNep halted fibrosis both in vitro and in vivo. In SSc fibroblasts, DZNep dose-dependently reduced the expression of profibrotic genes and inhibited migratory activity of SSc fibroblasts. We show that epigenetic dysregulation and overexpression of LRRC16A explains EZH2-mediated fibroblast migration in SSc. In endothelial cells, inhibition of EZH2 restored normal angiogenesis in SSc via activating the Notch pathway, specifically by up-regulating the Notch ligand DLL4. Our results demonstrate that overexpression of EZH2 in SSc fibroblasts and endothelial cells is profibrotic and antiangiogenic. Targeting EZH2 or EZH2-regulated genes might be of therapeutic potential in SSc.
| S-EPMC6397533 | biostudies-literature
Project description:The primary cause of mortality for glioblastoma (GBM) is local tumor recurrence following standard-of-care therapies, including surgical resection. With most tumors recurring near the site of surgical resection, local delivery of chemotherapy at the time of surgery is a promising strategy. Herein drug-loaded polymer scaffolds with two distinct degradation profiles were fabricated to investigate the effect of local drug delivery rate on GBM recurrence following surgical resection. The novel biopolymer, acetalated dextran (Ace-DEX), was compared with commercially available polyester, poly(l-lactide) (PLA). Steady-state doxorubicin (DXR) release from Ace-DEX scaffolds was found to be faster when compared with scaffolds composed of PLA, in vitro. This increased drug release rate translated to improved therapeutic outcomes in a novel surgical model of orthotopic glioblastoma resection and recurrence. Mice treated with DXR-loaded Ace-DEX scaffolds (Ace-DEX/10DXR) resulted in 57% long-term survival out to study completion at 120 days compared with 20% survival following treatment with DXR-loaded PLA scaffolds (PLA/10DXR). Additionally, all mice treated with PLA/10DXR scaffolds exhibited disease progression by day 38, as defined by a 5-fold growth in tumor bioluminescent signal. In contrast, 57% of mice treated with Ace-DEX/10DXR scaffolds displayed a reduction in tumor burden, with 43% exhibiting complete remission. These results underscore the importance of polymer choice and drug release rate when evaluating local drug delivery strategies to improve prognosis for GBM patients undergoing tumor resection.
| S-EPMC5999333 | biostudies-literature
Project description:Glioblastoma multiforme (GBM) heterogeneity causes a greater number of deaths than any other brain tumor, despite the availability of alkylating chemotherapy. GBM stem-like cells (GSCs) contribute to GBM complexity and chemoresistance, but it remains challenging to identify and target GSCs or factors that control their activity. Here, we identified a specific GSC subset and show that activity of these cells is positively regulated by stabilization of methyl CpG binding domain 3 (MBD3) protein. MBD3 binds to CK1A and to BTRCP E3 ubiquitin ligase, triggering MBD3 degradation, suggesting that modulating this circuit could antagonize GBM recurrence. Accordingly, xenograft mice treated with the CK1A activator pyrvinium pamoate (Pyr-Pam) showed enhanced MBD3 degradation in cells expressing high levels of O6-methylguanine-DNA methyltransferase (MGMT) and in GSCs, overcoming temozolomide chemoresistance. Pyr-Pam blocked recruitment of MBD3 and the repressive nucleosome remodeling and deacetylase (NuRD) complex to neurogenesis-associated gene loci and increased acetyl-histone H3 activity and GSC differentiation. We conclude that CK1A/BTRCP/MBD3/NuRD signaling modulates GSC activation and malignancy, and that targeting this signaling could suppress GSC proliferation and GBM recurrence.
| S-EPMC7598052 | biostudies-literature
Project description:Pemphigus vulgaris (PV) is a life-threatening autoimmune blistering skin disease characterized by detachment of keratinocytes (acantholysis). It has been proposed that PV IgG might trigger signaling and that this process may lead to acantholysis. Indeed, we recently identified a rapid and dose-dependent phosphorylation of p38 mitogen-activated protein kinase (p38MAPK) and heat shock protein (HSP) 27 after binding of PV antibodies to cultured keratinocytes. In human keratinocyte cultures, inhibitors of p38MAPK prevented PV IgG-induced phosphorylation of HSP27 and, more importantly, prevented the early cytoskeletal changes associated with loss of cell-cell adhesion. This study was undertaken to (i) determine whether p38MAPK and HSP25, the murine HSP27 homolog, were similarly phosphorylated in an in vivo model of PV and (ii) investigate the potential therapeutic use of p38MAPK inhibition to block blister formation in an animal model of PV. We now report that p38MAPK inhibitors prevented PV blistering disease in vivo. Targeting the end-organ by inhibiting keratinocyte desmosome signaling may be effective for treating desmosome autoimmune blistering disorders.
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Project description:Purpose: Conventional chemotherapy has modest efficacy in advanced adenoid cystic carcinomas (ACC). Tumor recurrence is a major challenge in the management of ACC patients. Here, we evaluated the antitumor effect of a novel small-molecule inhibitor of the MDM2-p53 interaction (MI-773) combined with cisplatin in patient-derived xenograft (PDX) ACC tumors.Experimental Design: Therapeutic strategies with MI-773 and/or cisplatin were evaluated in SCID mice harboring PDX ACC tumors (UM-PDX-HACC-5) and in low passage primary human ACC cells (UM-HACC-2A, -2B, -5, -6) in vitro The effect of therapy on the fraction of cancer stem cells (CSC) was determined by flow cytometry for ALDH activity and CD44 expression.Results: Combined therapy with MI-773 with cisplatin caused p53 activation, induction of apoptosis, and regression of ACC PDX tumors. Western blots revealed induction of MDM2, p53 and downstream p21 expression, and regulation of apoptosis-related proteins PUMA, BAX, Bcl-2, Bcl-xL, and active caspase-9 upon MI-773 treatment. Both single-agent MI-773 and MI-773 combined with cisplatin decreased the fraction of CSCs in PDX ACC tumors. Notably, neoadjuvant MI-773 and surgery eliminated tumor recurrences during a postsurgical follow-up of more than 300 days. In contrast, 62.5% of mice that received vehicle control presented with palpable tumor recurrences within this time period (P = 0.0097).Conclusions: Collectively, these data demonstrate that therapeutic inhibition of MDM2-p53 interaction by MI-773 decreased the CSC fraction, sensitized ACC xenograft tumors to cisplatin, and eliminated tumor recurrence. These results suggest that patients with ACC might benefit from the therapeutic inhibition of the MDM2-p53 interaction. Clin Cancer Res; 23(4); 1036-48. ©2016 AACR.
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Project description:Glioblastoma (GBM) are aggressive brain tumors with limited treatment options. Cancer stem-like cells (CSLCs) contribute to GBM invasiveness, representing promising targets. BAL101553, a prodrug of BAL27862, is a novel small molecule tubulin-binding agent, promoting tumor cell death through spindle assembly checkpoint activation, which is currently in Phase 1/2a in advanced solid tumor patients including GBM. This study aimed to evaluate long-term daily oral BAL101553 treatment of mice orthotopically grafted with GBM CSLCs (GBM6) according to EB1 expression-level, and to decipher its mechanism of action on GBM stem cells. Oral treatment with BAL101553 for 100 days provoked a large EB1 expression level-dependent survival benefit, together with a decrease in tumor growth and brain invasion. Formation of vascular structures by the fluorescent GBM6-GFP-sh0 cells, mimicking endothelial vascular networks, was observed in the brains of control grafted mice. Following BAL101553 treatment, vessels were no longer detectable, suggesting inhibition of the endothelial trans-differentiation of GBM stem cells. In vitro, BAL27862 treatment resulted in a switch to the endothelial-like phenotype of GBM6 towards an astrocytic phenotype. Moreover, the drug inhibited secretion of VEGF, thus preventing normal endothelial cell migration activated by CSLCs. The decrease in VEGF secretion was confirmed in a human GBM explant following drug treatment. Altogether, our data first confirm the potential of EB1 expression as a response-predictive biomarker of BAL101553 in GBM we previously published and add new insights in BAL101553 long-term action by counteracting CSLCs mediated tumor angiogenesis. Our results strongly support BAL101553 clinical studies in GBM patients.
| S-EPMC7055546 | biostudies-literature
Project description:OBJECTIVE:The E26 transformation-specific domain transcription factor Etv2/Etsrp/ER71 is a master regulator of vascular endothelial differentiation during vasculogenesis, although its later role in sprouting angiogenesis remains unknown. Here, we investigated in the zebrafish model a role for Etv2 and related E26 transformation-specific factors, Fli1a and Fli1b in developmental angiogenesis. APPROACH AND RESULTS:Zebrafish fli1a and fli1b mutants were obtained using transposon-mediated gene trap approach. Individual fli1a and fli1b homozygous mutant embryos display normal vascular patterning, yet the angiogenic recovery observed in older etv2 mutant embryos does not occur in embryos lacking both etv2 and fli1b. Etv2 and fli1b double-deficient embryos fail to form any angiogenic sprouts and show greatly increased apoptosis throughout the axial vasculature. In contrast, fli1a mutation did not affect the recovery of etv2 mutant phenotype. Overexpression analyses indicate that both etv2 and fli1b, but not fli1a, induce the expression of multiple vascular markers and of each other. Temporal inhibition of Etv2 function using photoactivatable morpholinos indicates that the function of Etv2 and Fli1b during angiogenesis is independent from the early requirement of Etv2 during vasculogenesis. RNA-Seq analysis and chromatin immunoprecipitation suggest that Etv2 and Fli1b share the same transcriptional targets and bind to the same E26 transformation-specific sites. CONCLUSIONS:Our data argue that there are 2 phases of early vascular development with distinct requirements of E26 transformation-specific transcription factors. Etv2 alone is required for early vasculogenesis, whereas Etv2 and Fli1b function redundantly during late vasculogenesis and early embryonic angiogenesis.
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