ATRX loss in glioma results in dysregulation of cell-cycle phase transition and ATM inhibitor radio-sensitization

Abstract Gliomas are a leading cause of cancer mortality in children and adults, and new targeted therapies are desperately needed. ATRX is a chromatin remodeling protein that is recurrently mutated in H3F3A-mutant pediatric glioblastoma (GBM) and IDH-mutant grade 2/3 adult glioma. We previously showed that loss of ATRX in glioma results in tumor growth and additional tumor mutations. However, the mechanism driving these phenotypes has not been fully established. We found that in ChIP-Seq/ChIP-qPCR of mouse neuronal precursor cells (NPCs) and GBM cells with isogenic ATRX loss, ATRX binds regulatory elements for cell cycle phase transition gene sets, and ATRX loss subsequently results in reduced expression. Furthermore, human GBM cells with ATRX knock-out demonstrate higher rates of cells in S and G2/M phases, with clusters of cells demonstrating reduced expression of cell cycle regulatory gene sets by single-cell sequencing (scSeq) analysis. In human and mouse GBM in vitro models, ATRX-deficient cells exhibit a seven-fold increase in mitotic index at 16 hours after sub-lethal radiation and enhanced activation of the master cell cycle regulator ATM with radiation. Treatment of ATRX-deficient gliomas with ATM inhibitors results in a selective increase in dysfunctional cell cycling and increased radio-sensitization in ATRX-deficient glioma cells. Using an ATM-luciferase reporter in orthotopically-implanted human GBM cells, both AZD0156 and AZD1390 demonstrate in vivo pathway inhibition. Mice intra-cranially implanted with ATRX-deficient GBM cells demonstrate a doubling of median survival compared to radiated controls (p=0.0018) when treated with AZD0156 combined with radiation; this is not seen in ATRX-sufficient models. This study demonstrates that ATRX-deficient high-grade gliomas display epigenetic dysregulation of cell cycle phase transitions, which opens a new window for therapies targeting this unique phenotype.

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Growth Conditions and Cell Cycle Phase Modulate Phase Transition Temperatures in RBL-2H3 Derived Plasma Membrane Vesicles

PLoS ONE ◽

10.1371/journal.pone.0137741 ◽

2015 ◽

Vol 10 (9) ◽

pp. e0137741 ◽

Cited By ~ 27

Author(s):

Erin M. Gray ◽

Gladys Díaz-Vázquez ◽

Sarah L. Veatch

Keyword(s):

Phase Transition ◽

Cell Cycle ◽

Plasma Membrane ◽

Membrane Vesicles ◽

Growth Conditions ◽

Cell Cycle Phase ◽

Cycle Phase ◽

Transition Temperatures ◽

Plasma Membrane Vesicles ◽

Phase Transition Temperatures

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Lauric Acid Modulates Cancer-Associated microRNA Expression and Inhibits the Growth of the Cancer Cell

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520620666200310091719 ◽

2020 ◽

Vol 20 (7) ◽

pp. 834-844

Author(s):

Poonam Verma ◽

Amit Ghosh ◽

Manisha Ray ◽

Saurav Sarkar

Keyword(s):

Phase Transition ◽

Cell Cycle ◽

Signal Transduction ◽

Lauric Acid ◽

Metabolic Pathways ◽

Cell Cycle Phase ◽

Tumour Suppressor ◽

Signalling Pathway ◽

Cycle Phase ◽

Cancerous Cell

Background: microRNAs are known to regulate various protein-coding gene expression posttranscriptionally. Fatty acids are cell membrane constituents and are also known to influence the biological activities of the cells like signal transduction, growth and differentiation of the cells, apoptosis induction, and other physiological functions. In our experiments, we used lauric acid to analyse its effects on human cancerous cell lines. Objective: Our objective was to speculate the miRNA expression profile in lauric acid treated and untreated cancerous cell lines and further study the metabolic pathways of the targeted tumour suppressor and oncogenes. Methods: The KB cells and HepG2 cells were treated with lauric acid and miRNA was isolated and the expression of tumour suppressor and oncogenic miRNA was measured by quantitative PCR. The untreated cells were used as control. The metabolic pathways of the target tumour suppressor and oncogenes were examined by GeneMANIA software. Results: Interestingly, the lauric acid treatment suppresses the expression of oncogenic miRNA and significantly upregulated the expression of some tumour suppressor miRNAs. GeneMANIA metabolic pathway revealed that the upregulated tumour suppressor miRNAs regulate several cancer-associated pathways such as DNA damage, signal transduction p53 class mediator, stem cell differentiation, cell growth, cell cycle phase transition, apoptotic signalling pathway, cellular response to stress and radiation, etc. whereas oncogenic miRNAs regulate the cancer-associated pathway like cell cycle phase transition, apoptotic signalling pathway, cell growth, response to oxidative stress, immune response activating cell surface protein signalling pathway, cyclin-dependent protein kinase activity, epidermal growth factor receptor signalling pathways, etc. Conclusion: In our study, we found that lauric acid works as an anticancer agent by altering the expression of miRNAs.

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