Activating Akt1 mutations alter DNA double strand break repair and radiosensitivity

Oeck, Sebastian; Al-Refae, Klaudia; Riffkin, Helena; Wiel, Gesa; Handrick, René; Klein, Diana; Iliakis, George; Jendrossek, Verena

doi:10.1038/srep42700

Cited by 34 publications

(49 citation statements)

References 51 publications

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“…In the present study, we confirmed our previous observations in an intact cellular system by showing that DNA-PKcs-deficient M059J glioblastoma cells failed to induce the S473 phosphorylation upon IR, whereas DNA-PKcs-proficient M059K cells showed a significant but transient increase of phosphorylation at S473 at 30 min after IR. This is consistent with our earlier findings that the overexpression of activation-associated Akt1 mutants Akt1-E17K and Akt1-TDSD accelerated the repair of radiation-induced DSB particularly between 2 h and 6 h after irradiation [7]. Herein, the ability of DNA-PKcs to phosphorylate Akt at S473, presumably in the nuclear compartment, might allow cells without genetically-induced aberrant Akt-activation to enhance DSB repair by phosphorylating downstream nuclear targets involved in the repair of radiation-induced DNA damage [6,7,24] (reviewed by Reference [5]).…”

Section: Discussionsupporting

confidence: 93%

“…In line with these findings, earlier reports suggested that active Akt1 rapidly translocates to the nucleus upon IR [7,34,35]. However, it remained controversial if cytoplasmic phosphorylation of Akt is dispensable for its nuclear access: Nguyen and colleagues showed that Akt1-TA and Akt1-SA failed to translocate to the nucleus in PC12 cells [36], whereas the double phosphorylation-deficient mutant Akt-TASA was found in the nuclear compartment using live imaging in hepatocellular carcinoma cells (HCC) [37].…”

Section: Discussionsupporting

confidence: 80%

“…Our own previous findings gained from an in vitro kinase assay demonstrated that DNA-PKcs indeed functions as an upstream kinase activating Akt1 at S473 in the presence of damaged DNA and not vice-versa [7] as suggested in other studies [27]. In the present study, we confirmed our previous observations in an intact cellular system by showing that DNA-PKcs-deficient M059J glioblastoma cells failed to induce the S473 phosphorylation upon IR, whereas DNA-PKcs-proficient M059K cells showed a significant but transient increase of phosphorylation at S473 at 30 min after IR.…”

Section: Discussionmentioning

confidence: 99%

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Restraining Akt1 Phosphorylation Attenuates the Repair of Radiation-Induced DNA Double-Strand Breaks and Reduces the Survival of Irradiated Cancer Cells

Szymonowicz

Oeck

Krysztofiak

et al. 2018

IJMS

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The survival kinase protein kinase B (Akt) participates in the regulation of essential subcellular processes, e.g., proliferation, growth, survival, and apoptosis, and has a documented role in promoting resistance against genotoxic stress including radiotherapy, presumably by influencing the DNA damage response and DNA double-strand break (DSB) repair. However, its exact role in DSB repair requires further elucidation. We used a genetic approach to explore the consequences of impaired phosphorylation of Akt1 at one or both of its key phosphorylation sites, Threonine 308 (T308) or Serine 473 (S473), on DSB repair and radiosensitivity to killing. Therefore, we overexpressed either the respective single or the double phosphorylation-deficient mutants (Akt1-T308A, Akt1-S473A, or Akt1-T308A/S473A) in TRAMPC1 murine prostate cancer cells (TrC1) and measured the DSB repair kinetics and clonogenic cell survival upon irradiation. Only the expression of the Akt1-T308A/S473A induced a significant delay in the kinetics of DSB repair in irradiated TrC1 as determined by the γH2A.X (H2A histone family, member X) assay and the neutral comet assay, respectively. Moreover, Akt1-T308A/S473A-expressing cells were characterized by increased radiosensitivity compared to Akt1-WT (wild type)-expressing cells in long-term colony formation assays. Our data reveal that Akt1’s activation state is important for the cellular radiation response, presumably by modulating the phosphorylation of effector proteins involved in the regulation of DSB repair.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

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Restraining Akt1 Phosphorylation Attenuates the Repair of Radiation-Induced DNA Double-Strand Breaks and Reduces the Survival of Irradiated Cancer Cells

Szymonowicz

Oeck

Krysztofiak

et al. 2018

IJMS

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“…AR and ESR1 involved in the regulation of gene expression and affect cellular proliferation [30,31]. AKT1 mediated many processes including metabolism, proliferation, cell survival, growth and angiogenesis [32]. FOXO3 triggers apoptosis in the absence of survival factors, including neuronal cell death upon oxidative stress [33].…”

Section: Discussionmentioning

confidence: 99%

The potential drug for treatment in pancreatic adenocarcinoma: a bioinformatical study based on distinct drug databases

et al. 2020

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Background: The prediction of drug-target interaction from chemical and biological data can advance our search for potential drug, contributing to a therapeutic strategy for pancreatic adenocarcinoma (PAAD). We aim to identify hub genes of PAAD and search for potential drugs from distinct databases. The docking simulation is adopted to validate our findings from computable perspective. Methods: Differently expressed genes (DEGs) of PAAD were performed based on TCGA. With two Cytoscape plugins of CentiScaPe and MCODE, hub genes were analyzed and visualized by STRING analysis of Protein-protein Interaction (PPI). The hub genes were further selected with significant prognostic values. In addition, we examined the correlation between hub genes and immune infiltration in PAAD. Subsequently, we searched for the hub gene-targeted drugs in Connectivity map (Cmap) and cBioportal, which provided a large body of candidate drugs. The hub gene, which was covered in the above two databases, was estimated in Traditional Chinese Medicine Systems Pharmacology (TCMSP) and Herbal Ingredients' Targets (HIT) database, which collected natural herbs and related ingredients. After obtaining molecular structures, the potential ingredient from TCMSP was applied for a docking simulation. We finalized a network connectivity of ingredient and its targets. Results: A total of 2616 DEGs of PAAD were identified, then we further determined and visualized 24 hub genes by a connectivity analysis of PPI. Based on prognostic value, we identified 5 hub genes including AURKA (p = 0.0059), CCNA2 (p = 0.0047), CXCL10 (p = 0.0044), ADAM10 (p = 0.00043), and BUB1 (p = 0.0033). We then estimated tumor immune correlation of these 5 hub genes, because the immune effector process was one major result of GO analysis. Subsequently, we continued to search for candidate drugs from Cmap and cBioportal database. BUB1, not covered in the above two databases, was estimated in TCMSP and HIT databases. Our results revealed that genistein was a potential drug of BUB1. Next, we generated two docking modes to validate drug-target interaction based on their 3D structures. We eventually constructed a network connectivity of BUB1 and its targets. Conclusions: All 5 hub genes that predicted poor prognosis had their potential drugs, especially our findings showed that genistein was predicted to target BUB1 based on TCMSP and docking simulation. This study provided a reasonable approach to extensively retrieve and initially validate putative therapeutic agents for PAAD. In future, these drug-target results should be investigated with solid data from practical experiments.

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“…Akt plays a central role in multiple cellular processes, including positively regulating cell survival under stress conditions. Activation of Akt was directly involved in the control of DNA repair and improved post-irradiation cell survival [Oeck et al, 2017]. Phosphorylation of p53 can be considered as a marker of radiation-induced apoptosis [Low et al, 2006].…”

Section: Discussionmentioning

confidence: 99%

Synergistic Ototoxicity of Gentamicin and Low-Dose Irradiation: Molecular Basis and Clinical Significance

2019

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Background: Inner ear structures may be included in the radiation fields when irradiation is used to treat patients with head and neck cancers. These patients may also have concurrent infections that require gentamicin treatment. Radiation and gentamicin are both potentially ototoxic, and their combined use has been shown to result in synergistic ototoxicity in animals. Objective: We aimed to confirm the synergistic ototoxicity of combined gentamicin and low-dose irradiation treatment and identify the underlying molecular mechanisms using an in vitro model. Method: We compared the ototoxic effects of gentamicin, low-dose irradiation, and their combination in the OC-k3 mouse cochlear cell line using cell viability assay, live/dead stain, apoptosis detection assay, oxidative stress detection, and studied the molecular mechanisms involved using immunoblot analysis. Results: Combined treatment led to prolonged oxidative stress, re-duced cell viability, and synergistic apoptosis. Gentamicin induced the concurrent accumulation of LC3b-II and SQSTM1/p62, suggesting an impairment of autophagic flux. Low-dose irradiation induced transient p53 phosphorylation and persistent Akt phosphorylation in response to DNA damage. In combined treatment, gentamicin attenuated irradiation-induced Akt activation. Conclusions: Besides increased oxidative stress, synergistic apoptosis observed in combined treatment could be attributed to gentamicin-induced perturbation of autophagic flux and attenuation of Akt phosphorylation, which led to an impairment of radiation-induced DNA repair response.

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Activating Akt1 mutations alter DNA double strand break repair and radiosensitivity

Cited by 34 publications

References 51 publications

Restraining Akt1 Phosphorylation Attenuates the Repair of Radiation-Induced DNA Double-Strand Breaks and Reduces the Survival of Irradiated Cancer Cells

Restraining Akt1 Phosphorylation Attenuates the Repair of Radiation-Induced DNA Double-Strand Breaks and Reduces the Survival of Irradiated Cancer Cells

The potential drug for treatment in pancreatic adenocarcinoma: a bioinformatical study based on distinct drug databases

Synergistic Ototoxicity of Gentamicin and Low-Dose Irradiation: Molecular Basis and Clinical Significance

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