scholarly journals The H3.3K27M oncohistone affects replication stress outcome and provokes genomic instability in pediatric glioma

PLoS Genetics ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. e1009868
Author(s):  
Irena Bočkaj ◽  
Tosca E. I. Martini ◽  
Eduardo S. de Camargo Magalhães ◽  
Petra L. Bakker ◽  
Tiny G. J. Meeuwsen-de Boer ◽  
...  
Keyword(s):  
Dna Replication ◽  
Genomic Instability ◽  
High Grade Glioma ◽  
Replication Stress ◽  
Nuclear Body ◽  
Tumor Formation ◽  
High Grade ◽  
Mitotic Abnormalities ◽  
Replication Factors

While comprehensive molecular profiling of histone H3.3 mutant pediatric high-grade glioma has revealed extensive dysregulation of the chromatin landscape, the exact mechanisms driving tumor formation remain poorly understood. Since H3.3 mutant gliomas also exhibit high levels of copy number alterations, we set out to address if the H3.3K27M oncohistone leads to destabilization of the genome. Hereto, we established a cell culture model allowing inducible H3.3K27M expression and observed an increase in mitotic abnormalities. We also found enhanced interaction of DNA replication factors with H3.3K27M during mitosis, indicating replication defects. Further functional analyses revealed increased genomic instability upon replication stress, as represented by mitotic bulky and ultrafine DNA bridges. This co-occurred with suboptimal 53BP1 nuclear body formation after mitosis in vitro, and in human glioma. Finally, we observed a decrease in ultrafine DNA bridges following deletion of the K27M mutant H3F3A allele in primary high-grade glioma cells. Together, our data uncover a role for H3.3 in DNA replication under stress conditions that is altered by the K27M mutation, promoting genomic instability and potentially glioma development.

scholarly journals CBIO-18. G-QUADRUPLEX STABILIZATION TARGETS ATRX-DEFICIENT HIGH-GRADE GLIOMA VIA INDUCTION OF p53-INDEPENDENT APOPTOSIS

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii19-ii19
Author(s):  
Sharvari Dharmaiah ◽  
Ahsan Farooqi ◽  
Christian Alvarez ◽  
Vladislav Sharin ◽  
David Irvin ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Flow Analysis ◽  
High Grade Glioma ◽  
Replication Stress ◽  
High Grade ◽  
Preclinical Models ◽  
Current Standard ◽  
G Quadruplex

Abstract Gliomas are the most common primary malignant brain tumor in adults and mutational inactivation of histone chaperone ATRX is a critical molecular marker in the classification of high-grade glioma (HGG). ATRX loss occurs with concurrent mutations in TP53 and IDH1/2, altering genome-wide accessibility of chromatin and inducing replication stress and DNA damage via accumulations of abnormal G-quadruplex (G4) DNA secondary structures. While G4 stabilizers in particular hold strong therapeutic promise, the genomic consequences and efficacy of this treatment are poorly understood. We previously showed that chemical stabilization of G4s in ATRX-deficient normal human astrocytes (NHAs) results in lethality due to induction of replication stress, but it is unknown what drives this lethality in ATRX-deficient patient-derived preclinical models. We therefore sought to evaluate the mechanisms that underlie cell death in ATRX- and p53-deficient preclinical in vitro models following G4 stabilization. We found that ATRX-deficient glioma stem cells (GSCs) demonstrated dose-dependent enhanced sensitivity to G4 stabilization, compared to ATRX-intact controls. Evaluation of cell death mechanisms following G4 stabilization revealed a significant increase in cleaved caspase 3 expression and no p21 expression in ATRX-deficient GSCs, suggesting p53-independent apoptotic activation. Cell cycle flow analysis demonstrated G2/M checkpoint arrest in ATRX-deficient GSCs upon G4 stabilization, suggesting that p53 is nonfunctional at the G1/S checkpoint. Our preliminary findings now suggest that p73, a functional and structural homologue of p53, is activated and drives apoptosis in these ATRX-deficient GSCs. Furthermore, ATRX-deficient GSCs demonstrated upregulated expression of both pATR/pChk1 and pATM/pChk2, indicating enhanced replication stress and DNA damage via double-stranded breaks, respectively. These findings indicate that G4 stabilizers could potentially synergize with ionizing radiation, the current standard of care, as both therapies are DNA-damaging. Taken together, this study elucidates mechanisms of cytotoxicity and efficacy of a novel therapeutic strategy in ATRX-deficient preclinical models.

scholarly journals HGG-31. HISTONE H3.3 G34R/V MUTATIONS STIMULATE PEDIATRIC HIGH-GRADE GLIOMA FORMATION THROUGH THE INDUCTION OF CHROMOSOMAL INSTABILITY

2021 ◽  
Vol 23 (Supplement_1) ◽  
pp. i23-i23
Author(s):  
Florina Grigore ◽  
James Robinson ◽  
Alyssa Langfald ◽  
Edward Hinchcliffe ◽  
Charles Day
Keyword(s):  
Chromosomal Instability ◽  
High Grade Glioma ◽  
Tumor Formation ◽  
Kinase Assay ◽  
Aneuploid Cell ◽  
High Grade ◽  
Histone H3.3 ◽  
In Vitro Kinase Assay ◽  
Diploid Cells

Abstract The histone H3.3 G34R/V mutations are known drivers of high-grade pediatric glioma (pHGG). However, the mechanism(s) for H3.3 G34R/V induced tumor formation are unclear. Chk1 phosphorylates H3.3 S31 at the pericentromere during early mitosis, suggesting a novel mitotic function. We observed that H3.3 G34 mutant pHGG cells have reduced mitotic H3.3 S31 phosphorylation compare to WT H3.3 cell lines. The H3.3 G34R mutation reduced Chk1 phosphorylation at S31 by >90% in an in vitro kinase assay. Overexpression of either H3.3 G34R or non-phosphorylatable S31A in H3.3 WT, diploid cells led to a significant increase in chromosome mis-segregations. Likewise, H3.3 G34 mutant pHGG cells have significantly elevated rates of mis-segregation as compare to H3.3 WT pHGG cells. During normal cell division, phospho-S31 is lost in late anaphase. However, when chromosome missegregation occurs, phospho-S31 spreads and stimulates p53 accumulation in G1 – thus suppressing aneuploid cell proliferation. Here we show that cells expressing mutant G34 fail to arrest following mis-segregation, despite having WT p53. These studies demonstrate that the H3.3 G34R/V mutations are sufficient to transform normal, diploid cells into proliferative, chromosomally instable cells. To determine if this process contributes to tumorigenesis, we used the RCAS/TVA mouse model to overexpress H3.3 WT, G34R, or S31A in the glial precursor cells of mice pups. Over 100 days, S31A and G34R mice had drastically reduced survival (averaging 77, 81, and 100 days for S31A, G34R, and WT mice). Furthermore, most G34R and S31A mice developed HGG, while H3.3 WT mice remained tumor-free and did not develop high-grade tumors. Our work strongly indicates that a major factor in H3.3 G34R pHGG formation is the induction of chromosomal instability – which occurs directly through the suppression of H3.3 S31 phosphorylation.

scholarly journals Advanced Spheroid, Tumouroid and 3D Bioprinted In-Vitro Models of Adult and Paediatric Glioblastoma

2021 ◽  
Vol 22 (6) ◽  
pp. 2962
Author(s):  
Louise Orcheston-Findlay ◽  
Samuel Bax ◽  
Robert Utama ◽  
Martin Engel ◽  
Dinisha Govender ◽  
...  
Keyword(s):  
Life Expectancy ◽  
High Throughput Screening ◽  
High Grade Glioma ◽  
Tumour Microenvironment ◽  
In Vitro Models ◽  
Treatment Modalities ◽  
High Grade ◽  
Future Improvement ◽  
Complex Models

The life expectancy of patients with high-grade glioma (HGG) has not improved in decades. One of the crucial tools to enable future improvement is advanced models that faithfully recapitulate the tumour microenvironment; they can be used for high-throughput screening that in future may enable accurate personalised drug screens. Currently, advanced models are crucial for identifying and understanding potential new targets, assessing new chemotherapeutic compounds or other treatment modalities. Recently, various methodologies have come into use that have allowed the validation of complex models—namely, spheroids, tumouroids, hydrogel-embedded cultures (matrix-supported) and advanced bioengineered cultures assembled with bioprinting and microfluidics. This review is designed to present the state of advanced models of HGG, whilst focusing as much as is possible on the paediatric form of the disease. The reality remains, however, that paediatric HGG (pHGG) models are years behind those of adult HGG. Our goal is to bring this to light in the hope that pGBM models can be improved upon.

scholarly journals SPOP promotes transcriptional expression of DNA repair and replication factors to prevent replication stress and genomic instability

2018 ◽  
Vol 46 (18) ◽  
pp. 9891-9891 ◽  
Author(s):  
Kim Hjorth-Jensen ◽  
Apolinar Maya-Mendoza ◽  
Nanna Dalgaard ◽  
Jón O Sigurðsson ◽  
Jiri Bartek ◽  
...  
Keyword(s):  
Dna Repair ◽  
Genomic Instability ◽  
Replication Stress ◽  
Transcriptional Expression ◽  
Replication Factors

CBIO-11. HISTONE H3.3 G34R/V MUTATIONS STIMULATE PEDIATRIC HIGH-GRADE GLIOMA FORMATION THROUGH THE INDUCTION OF CHROMOSOMAL INSTABILITY

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi29-vi29
Author(s):  
Charles Day ◽  
Florina Grigore ◽  
Alyssa Langfald ◽  
Edward Hinchcliffe ◽  
James Robinson
Keyword(s):  
Gene Regulation ◽  
Chromosomal Instability ◽  
High Grade Glioma ◽  
Kinase Assay ◽  
High Grade ◽  
Newborn Mice ◽  
Cycle Arrest ◽  
Epigenetic Gene Regulation ◽  
Diploid Cells

Abstract H3.3 G34R/V mutations are drivers of high-grade pediatric glioma (pHGG). H3.3 G34R/V mutations are linked to altered H3.3 K36 trimethylation (H3K36me3); implicating epigenetic gene regulation as a possible contributor to pHGG formation. Here we show that H3.3 G34R/V also induces chromosomal instability (CIN); a hallmark of pHGG. If CIN promotes pHGG formation is unknown. We observed that H3.3 G34 mutant pHGG cells have reduced mitotic H3.3 S31 phosphorylation compare to WT H3.3 cell lines. And, H3.3 G34R reduced Chk1 phosphorylation at S31 by >90% in an in vitro kinase assay. Chk1 regulates chromosome segregation through phosphorylation of pericentromeric H3.3 S31 during early mitosis. Overexpression of H3.3 G34R or non-phosphorylatable S31A in H3.3 WT, diploid cells caused a significant increase in CIN. Likewise, H3.3 G34 mutant pHGG cells have significantly elevated rates of CIN as compare to H3.3 WT pHGG cells. During normal cell division, phospho-S31 is lost in anaphase. However, following chromosome missegregation, phospho-S31 spreads and stimulates p53-induced cell cycle arrest. Here we show that WT p53 cells expressing mutant G34 fail to arrest following chromosome mis-segregation. These studies demonstrate that H3.3 G34R/V mutations are sufficient to transform normal, diploid cells into proliferating CIN cells. To determine if this process contributes to tumorigenesis, we used RCAS Nestin-TVA mice to overexpress H3.3 WT, G34R, or S31A – P2A-linked to PDGFB expression in glial precursor cells of newborn mice. Over 100 days, S31A and G34R mice had drastically reduced survival (averaging 77, 81, and 100 days for S31A, G34R, and WT). Furthermore, most G34R and S31A mice developed HGG, while H3.3 WT mice remained tumor-free. Our work implicates CIN as a driver of H3.3 G34 mutant pHGG formation. Our ongoing studies utilize K36M and double mutants to further define the contributions of S31 phosphorylation (CIN) and H3K36me3 (epigenetic gene regulation) to tumorigenesis.

scholarly journals ACTR-59. A PHASE 1 STUDY OF BPM31510 PLUS VITAMIN K IN SUBJECTS WITH HIGH-GRADE GLIOMA THAT HAS RECURRED ON A BEVACIZUMAB-CONTAINING REGIMEN

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi27-vi27
Author(s):  
Lawrence Recht ◽  
Reena Thomas ◽  
Sophie Bertrand ◽  
Priya Yerballa ◽  
Gordon Li ◽  
...  
Keyword(s):  
Phase I ◽  
Vitamin K ◽  
Phase I Study ◽  
Phase 1 ◽  
High Grade Glioma ◽  
High Grade ◽  
Open Label ◽  
Open Label Phase ◽  
Grade 3

Abstract BACKGROUND High-grade gliomas (HGG) are characterized by dysregulated metabolism, utilizing glycolysis for energy production to support unrestricted growth. BPM 31510, an ubidecarenone (coenzyme Q10) containing lipid nanodispersion, causes a switch in cancer energy sourcing from glycolysis towards mitochondrial oxidative phosphorylation in vitro, reversing the Warburg effect and suggesting potential as an anti-tumor agent. The current study is a phase I study of BPM31510 + vitamin K in GB with tumor growth after bevacizumab (BEV). METHODS This is an open-label phase I study of BPM31510 continuous infusion with weekly vitamin K (10mg IM) in HGG patients using an mTPI design, starting at 110mg/kg, allowing for a single dose de-escalation and 2 dose-escalations. Patients had received first-line ChemoRadiation and were in recurrence following a BEV containing regimen. RESULTS 9 eligible and evaluable patients completed the 28 day DLT period. 8 patients had primary GB, 1 had anaplastic astrocytoma with confirmed pathologic transformation to GB. Median age was 55 years (27–67) and median KPS 70 (60–90) at enrollment. 4 patients were treated at the highest dose 171mg/kg, where there was a single DLT: Grade 3 AST & ALT. The most common grade 1–2 AEs possibly, probably or definitely related to drug were elevated AST, rash, and fatigue, each occurring in 3 patients. Median OS for 9 eligible/evaluable patients was 128 days (95% CI: 48–209) while PFS was 34 days (CI of mean 8.9). 3 patients are currently alive; 2 patients have survived >1 year. PK/PD data are being processed and will be presented. CONCLUSION This study confirms that BPM 31510 + vitamin K is safe and feasible in treatment-refractory HGG patients. Though this study demonstrates safety at 171mg/kg, the proposed dose for future studies in GB, based on additional pre-clinical and non-GB clinical data is 88mg/kg.

β-arrestin 1 transfection induced cell death in high grade glioma in vitro

2020 ◽  
pp. 1-12
Author(s):  
Catalin Folcuti ◽  
Cristina Horescu ◽  
Edmond Barcan ◽  
Oana Alexandru ◽  
Cristian Tuta ◽  
...  
Keyword(s):  
Cell Death ◽  
High Grade Glioma ◽  
High Grade

Tolerability and preliminary efficacy of BXQ-350 for refractory solid tumors and high-grade gliomas: First-in-human, first-in-class phase I trial.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 3505-3505
Author(s):  
Olivier Rixe ◽  
John Charles Morris ◽  
Robert Wesolowski ◽  
Emrullah Yilmaz ◽  
Richard Curry ◽  
...  
Keyword(s):  
Solid Tumors ◽  
Dose Level ◽  
Human Study ◽  
Treatment Protocol ◽  
High Grade Glioma ◽  
Maximum Tolerated Dose ◽  
High Grade ◽  
Serious Adverse Events

3505 Background: BXQ-350 is a first-in-class agent comprised of Saposin C (SapC) and dioleoyl phosphatidylserine (DOPS). SapC, a multifunctional lysosomal-activator glycoprotein that preferentially interacts with tumor cell phospholipids, has demonstrated anti-tumor effects in both in vitro and in vivo preclinical models. The tolerability and preliminary efficacy of BXQ-350 in the first-in-human study are summarized here. Methods: Eighty-six refractory solid tumor (ST) or high-grade glioma (HGG) patients age ≥18 (36F:50M, age 24-81) were enrolled in a 3-part first-in-human trial (NCT02859857) from 2016-2019 and received at least one dose of BXQ-350. Doses were administered via intravenous infusion during 28-day cycles until disease progression occurred. The previously reported part 1 dose escalation portion of the study (9 HGG, 9 ST patients) established the highest planned dose of 2.4mg/kg as safe but did not identify a maximum tolerated dose. The part 2 expansion cohort treated 37 patients (18 HGG and 19 ST) and an additional part 3 cohort treated 31 ST gastrointestinal (GI) patients, both at the 2.4 mg/kg dose level. Preliminary antitumor activity was evaluated (RECISTv1.1 or RANO). Results: There were no BXQ-350-related serious adverse events, dose limiting toxicities or withdrawals with the exception of 1 allergic type reaction. Three patients (Glioblastoma, Ependymoma, Appendiceal) demonstrated a partial response per RECIST/RANO. Two HGG patients with progressive radiologic enhancement were seen to have treatment effect at surgery, and hence considered to have stable disease. Seven patients (2 HGG, 3 GI, 2 other ST) remain on study and have received treatment for 9+ to 41+ months, with 5 patients treated for > 1 year. A continuing treatment protocol is planned in order to allow these patients to remain on BXQ-350 treatment. Conclusions: BXQ-350 was well tolerated with no significant dose-limiting toxicities at the highest planed dose level. Preliminary results indicate this novel agent demonstrated possible anti-tumor activity in refractory solid tumors and HGG. Clinical trial information: NCT03967093) .

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