Dataset Information

Inhibition of ATM kinase upregulates levels of cell death induced by cannabidiol and ?-irradiation in human glioblastoma cells.

ABSTRACT: Despite advances in glioblastoma (GBM) therapy, prognosis of the disease remains poor with a low survival rate. Cannabidiol (CBD) can induce cell death and enhance radiosensitivity of GBM but not normal astrocytes. Inhibition of ATM kinase is an alternative mechanism for radiosensitization of cancer cells. In this study, we increased the cytotoxic effects of the combination of CBD and ?-irradiation in GBM cells through additional inhibition of ATM kinase with KU60019, a small molecule inhibitor of ATM kinase. We observed in GBM cells treated by CBD, ?-irradiation and KU60019 high levels of apoptosis together with strong upregulation of the percentage of G2/M-arrested cells, blockade of cell proliferation and a massive production of pro-inflammatory cytokines. Overall, these changes caused both apoptotic and non-apoptotic inflammation-linked cell death. Furthermore, via JNK-AP1 activation in concert with active NF-?B, CBD upregulated gene and protein expression of DR5/TRAIL-R2 and sensitize GBM cells to TRAIL-induced apoptosis. In contrast, CBD notably decreased in GBM surface levels of PD-L1, a critical immune checkpoint agent for T-lymphocytes. We also used in the present study TS543 human proneural glioma cells that were grown as spheroid culture. TS543 neurospheres exhibited dramatic sensitivity to CBD-mediated killing that was additionally increased in combination with ?-irradiation and KU60019. In conclusion, treatment of human GBM by the triple combination (CBD, ?-irradiation and KU60019) could significantly increase cell death levels in vitro and potentially improve the therapeutic ratio of GBM.

SUBMITTER: Ivanov VN

PROVIDER: S-EPMC6368233 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

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Inhibition of ATM kinase upregulates levels of cell death induced by cannabidiol and γ-irradiation in human glioblastoma cells.

Ivanov Vladimir N VN Wu Jinhua J Wang Tony J C TJC Hei Tom K TK

Oncotarget 20190125 8

Despite advances in glioblastoma (GBM) therapy, prognosis of the disease remains poor with a low survival rate. Cannabidiol (CBD) can induce cell death and enhance radiosensitivity of GBM but not normal astrocytes. Inhibition of ATM kinase is an alternative mechanism for radiosensitization of cancer cells. In this study, we increased the cytotoxic effects of the combination of CBD and γ-irradiation in GBM cells through additional inhibition of ATM kinase with KU60019, a small molecule inhibitor ...[more]

PMID: 30783513

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Project description:DNA damage response (DDR) is a complex process, essential for cell survival. Especially deleterious type of DNA damage are DNA double-strand breaks (DSB), which can lead to genomic instability and malignant transformation if not repaired correctly. The central player in DSB detection and repair is the ATM kinase which orchestrates the action of several downstream factors. Despite substantial knowledge of DNA repair processes, still several aspects of DNA damage detection and signaling are not fully understood. Recent studies have suggested that long non-coding RNAs (lncRNAs) are involved in DDR. Here, we aimed to identify lncRNAs induced upon DNA damage in an ATM-dependent manner. 7 mRNAs and 10 lncRNAs were significantly induced 1h after ionizing radiation (IR) in healthy donors, whereas none in AT patients. 447 mRNAs and 149 lncRNAs were induced 8h after IR in the control group, while only 100 mRNAs and 3 lncRNAs in AT patients. Among IR-induced mRNAs, we found several genes with well-known functions in DDR. Gene Set Enrichment Analysis and Gene Ontology revealed delayed induction of key DDR pathways in AT patients compared to controls. The induction and dynamics of selected 9 lncRNAs were confirmed by RT-qPCR at several time-points after IR on a larger cohort. Moreover, inhibition of ATM with a specific inhibitor (KU-60019) proved that those lncRNAs are dependent on ATM. Some of the detected lncRNAs are localized next to protein-coding genes involved in DDR. We observed that induction of lncRNAs after IR preceded changes in expression of adjacent genes. This indicates that IR-induced lncRNAs may regulate the transcription of nearby genes. Subcellular fractionation into chromatin, nuclear, and cytoplasmic fractions revealed that the majority of studied lncRNAs are localized in chromatin, which further suggests their role in regulation of gene expression. In summary, our study revealed several lncRNAs induced by IR in an ATM-dependent manner. Their co-localization and co-expression with genes involved in DDR suggest that those lncRNAs may be important players in cellular response to DNA damage.

Project description:Proton Bragg peak irradiation has a higher ionizing density than conventional photon irradiation or the entrance of the proton beam profile. Whether targeting the DNA damage response (DDR) could enhance vulnerability to the distinct pattern of damage induced by proton Bragg peak irradiation is currently unknown. Here, we performed genetic or pharmacologic manipulation of key DDR elements and evaluated DNA damage signaling, DNA repair, and tumor control in cell lines and xenografts treated with the same physical dose across a radiotherapy linear energy transfer spectrum. Radiotherapy consisted of 6 MV photons and the entrance beam or Bragg peak of a 76.8 MeV spot scanning proton beam. More complex DNA double-strand breaks (DSB) induced by Bragg peak proton irradiation preferentially underwent resection and engaged homologous recombination (HR) machinery. Unexpectedly, the ataxia-telangiectasia mutated (ATM) inhibitor, AZD0156, but not an inhibitor of ATM and Rad3-related, rendered cells hypersensitive to more densely ionizing proton Bragg peak irradiation. ATM inhibition blocked resection and shunted more DSBs to processing by toxic ligation through nonhomologous end-joining, whereas loss of DNA ligation via XRCC4 or Lig4 knockdown rescued resection and abolished the enhanced Bragg peak cell killing. Proton Bragg peak monotherapy selectively sensitized cell lines and tumor xenografts with inherent HR defects, and the repair defect induced by ATM inhibitor coadministration showed enhanced efficacy in HR-proficient models. In summary, inherent defects in HR or administration of an ATM inhibitor in HR-proficient tumors selectively enhances the relative biological effectiveness of proton Bragg peak irradiation. SIGNIFICANCE: Coadministration of an ATM inhibitor rewires DNA repair machinery to render cancer cells uniquely hypersensitive to DNA damage induced by the proton Bragg peak, which is characterized by higher density ionization.See related commentary by Nickoloff, p. 3156.

Dataset Information

Inhibition of ATM kinase upregulates levels of cell death induced by cannabidiol and ?-irradiation in human glioblastoma cells.

Publications

Inhibition of ATM kinase upregulates levels of cell death induced by cannabidiol and γ-irradiation in human glioblastoma cells.

Similar Datasets

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