Corrigendum: A longitudinal investigation of quality of life and negative emotions in misophonia

[This corrects the article DOI: 10.3389/fnins.2022.900474.].

Work fatigue during COVID-19 lockdown teleworking: the role of psychosocial, environmental, and social working conditions

Background

During national lockdowns in response to the COVID-19 pandemic, previously office-based workers who transitioned to home-based teleworking faced additional demands (e.g., childcare, inadequate homeworking spaces) likely resulting in poor work privacy fit. Previous office research suggests poor work privacy fit is associated with lower wellbeing and higher work fatigue. Emerging evidence suggests a relationship between childcare duties during pandemic teleworking and work fatigue. In addition to psychosocial working conditions (job demand, job control, and job change management), which are acknowledged predictors of work fatigue, this poses a significant threat to occupational health during pandemic teleworking. However, the relative effects of aspects of the psychosocial environment (job demands and resources), the home office environment (including privacy fit), and the social environment (childcare) on work fatigue as well as their interactions are under-explored.

Objective

This study examined the relationships between the psychosocial, environmental, and social working conditions of teleworking during the first COVID-19 lockdown and work fatigue. Specifically, the study examined teleworkers' physical work environment (e.g., if and how home office space is shared, crowding, and noise perceptions) as predictors of privacy fit and the relationship between privacy fit, childcare, psychosocial working conditions (job demand, job control, and job change management), and work fatigue. Work privacy fit was hypothesized to mediate the relationship between childcare and work fatigue.

Methods

An online cross-sectional survey was conducted with teleworkers (n = 300) during the first COVID-19 lockdown in April and May 2020; most participants were in Germany, Switzerland, and the United Kingdom.

Results

Path analysis was used to examine the hypothesized relationships. Privacy fit was lower for those reporting greater levels of noise in home-working spaces and those feeling crowded at home. Work fatigue was lower amongst those with greater privacy fit and higher amongst those with high levels of job demand. An indirect relationship was observed between childcare and work fatigue with privacy fit mediating this relationship.

Conclusion

The influence of privacy fit has so far been largely neglected in research on teleworking, especially during the pandemic. However, its contribution to workers' wellbeing should be acknowledged in occupational health strategies.

Antibiotic prescription patterns and non-clinical factors influencing antibiotic use by Ecuadorian veterinarians working on cattle and poultry farms: A cross-sectional study

Understanding antibiotic prescription patterns and non-clinical factors influencing antibiotic use is essential for implementing strategies to promote appropriate antibiotic use. There is, however, limited research exploring these issues with Ecuadorian veterinarians. Therefore, a questionnaire was developed and applied cross-sectionally to veterinarians (n = 173) from two professional organizations to explore the antibiotic prescription patterns and non-clinical factors (e.g., attitudes and perceptions) influencing antibiotic use, and to identify strategies to reduce antibiotic use. The response rate was 78.4%. Responses were compared between veterinarians working mainly on cattle and poultry farms using Mann-Whitney U tests. The most important attitudes, beliefs and perceptions towards antimicrobial resistance (AMR) and antibiotic use were identified with the Relative Importance Index (RII). Veterinarians showed high awareness of AMR and its implications for public health, as well as the necessity of reducing antibiotic use. However, some veterinarians appear to underestimate the potential contribution of veterinary antibiotic use on AMR in humans. Veterinarians self-reported high prescription (> 20%) of antibiotics for cattle and poultry that are critically important for human medicine, such as 3rd and 4th generation cephalosporins, polymyxins and quinolones. Further, antibiotic therapy was not tailored to disease type. Cattle and poultry veterinarians perceived similar barriers to increasing antibiotic stewardship including: poor biosecurity measures, animal confinement, low feed quality, farmers' behaviors (such as stopping antibiotic treatment, storing antibiotics on farms, buying antibiotics in veterinary supply stores), and sales agents' roles as non-professional prescribers of antibiotics. Overall, veterinarians were broadly supportive (>90%) of most strategies to promote appropriate antibiotic use. They saw more merit in improving biosecurity of farms and implementing educational programs for farmers and veterinarians. This study provides insight into the complexity of antibiotic use on Ecuadorian farms and the need for holistic strategies in a One Health context, to achieve antibiotic stewardship.

Reaching a Tipping Point: A Qualitative Exploration of Quality of Life and Treatment Decision-Making in People Living With Benign Prostatic Hyperplasia

Benign prostatic hyperplasia (BPH) is a common condition amongst older men and is associated with lower urinary tract symptoms and erectile dysfunction; these symptoms can be burdensome and negatively affect quality of life. Various surgical and pharmaceutical treatment options exist but there is a paucity of qualitative research exploring men's decision-making when seeking BPH treatment. This study qualitatively explored men's experience of living with BPH and seeking treatment for BPH. Twenty men (aged 52-75) were recruited from outpatient urology clinics at a hospital trust in Southern England. Data were collected using semi-structured interviews (via video or telephone call) and were audio-recorded; transcripts were analysed using thematic analysis. Four themes were generated: 'Impacts are about more than just physical symptoms', 'The path towards treatment', 'The process of information gathering' and 'Navigating hopes, fears and uncertainty'. Results indicate most men appear to seek treatment for BPH following a gradual, and sometimes lengthy, period of deterioration in symptoms; for some men, however, treatment seeking follows an acute episode of sudden or severe symptoms. The decision to proceed with surgical or minimally invasive treatment options appears to be dependent on men reaching a tipping point; they no longer perceive their symptoms as tolerable and feel their ability to cope with symptoms is reduced. Men each bring their own set of concerns and preferences about side effects and risk-benefit profiles of different treatments. Clinicians need to be sensitive to these individual differences and incorporate them into shared decision-making for choosing between treatment options for BPH.

A longitudinal investigation of quality of life and negative emotions in misophonia

Aims

This longitudinal study examined the role of anger, disgust, and anxiety in the experience of misophonia, the quality of life of those with self-reported misophonia in comparison to those without misophonia, and the association of misophonia and quality of life over time.

Methods

An online longitudinal survey was conducted, with misophonia, anger, disgust, anxiety, depression, self-esteem, and quality of life measured at two time points (6-months apart) in two groups of people (those with self-reported misophonia and those without misophonia).

Results

Anger and disgust emerged as the primary predictors of misophonic responses. Anxiety and depression were not significantly associated with misophonia over time. Differences in quality of life were observed between those with and without self-reported misophonia in the current study, with lower scores across the SF-36 domains of role limitations due to emotional problems, energy/fatigue, emotional wellbeing, social functioning, and general health for those with misophonia compared to those without misophonia. Compared with other studies, scores for those with self-reported misophonia were lower than those with long-term physical conditions, similar to those with tinnitus, but higher than those with obsessive compulsive disorder. Misophonia was predictive of quality of life over time but only on two domains: role limitations due to emotional problems (predictors: avoidance, emotional responses, and impact on participation in life) and pain (predictor: impact on participation in life). Depression remained a strong predictor of quality of life over time.

Conclusion

Anger and disgust are more strongly associated with the experience of misophonia than anxiety. Quality of life in people with self-reported misophonia is lower than in the general population and may be similar to those with tinnitus. Depression, avoiding triggers, the extent of the emotional response, and perceived impact on participation in life are associated with perceptions of lower quality of life over time for people with self-reported misophonia.

Future Teleworking Inclinations Post-COVID-19: Examining the Role of Teleworking Conditions and Perceived Productivity

Organisations have implemented intensive home-based teleworking in response to global COVID-19 lockdowns and other pandemic-related restrictions. Financial pressures are driving organisations to continue intensive teleworking after the pandemic. Understanding employees' teleworking inclinations post COVID-19, and how these inclinations are influenced by different factors, is important to ensure any future, more permanent changes to teleworking policies are sustainable for both employees and organisations. This study, therefore, investigated the relationships between the context of home-based teleworking during the pandemic (pandemic-teleworking conditions), productivity perceptions during home-based teleworking, and employees' future teleworking inclinations (FTI) beyond the pandemic. Specifically, the study examined whether pandemic-teleworking conditions related to the job, and the physical and social environments at home, influenced employees' FTI, and if perceptions of improved or reduced productivity mediated these relationships. Data were collected during April and May 2020 with a cross-sectional online survey of teleworkers (n = 184) in Germany, Switzerland, the United Kingdom, and other countries during the first COVID-19 lockdowns. Reported FTI were mixed. Most participants (61%) reported wanting to telework more post-pandemic compared to before the pandemic; however, 18% wanted to telework less. Hierarchical multiple regression analysis revealed that some teleworking conditions (job demands and work privacy fit) were positively associated with FTI. Other teleworking conditions (specifically, job change, job control, home office adequacy, and childcare) were not associated with FTI. Perceived changes in productivity mediated the relationship between work privacy fit and FTI. Findings highlight the role of work privacy fit and job demands in influencing pandemic productivity perceptions and teleworking inclinations post-pandemic. Results raise questions about the suitability and sustainability of home-based teleworking for all staff. As organisations plan to increase the proportion of teleworking post-pandemic, this study suggests there is a need to support employees who perceived their productivity to be poor while home-working during the pandemic.

ATM phosphorylates PP2A subunit A resulting in nuclear export and spatiotemporal regulation of the DNA damage response

Ataxia telangiectasia mutated (ATM) is a serine-threonine protein kinase and important regulator of the DNA damage response (DDR). One critical ATM target is the structural subunit A (PR65-S401) of protein phosphatase 2A (PP2A), known to regulate diverse cellular processes such as mitosis and cell growth as well as dephosphorylating many proteins during the recovery from the DDR. We generated mouse embryonic fibroblasts expressing PR65-WT, -S401A (cannot be phosphorylated), and -S401D (phospho-mimetic) transgenes. Significantly, S401 mutants exhibited extensive chromosomal aberrations, impaired DNA double-strand break (DSB) repair and underwent increased mitotic catastrophe after radiation. Both S401A and the S401D cells showed impaired DSB repair (nonhomologous end joining and homologous recombination repair) and exhibited delayed DNA damage recovery, which was reflected in reduced radiation survival. Furthermore, S401D cells displayed increased ERK and AKT signaling resulting in enhanced growth rate further underscoring the multiple roles ATM-PP2A signaling plays in regulating prosurvival responses. Time-lapse video and cellular localization experiments showed that PR65 was exported to the cytoplasm after radiation by CRM1, a nuclear export protein, in line with the very rapid pleiotropic effects observed. A putative nuclear export sequence (NES) close to S401 was identified and when mutated resulted in aberrant PR65 shuttling. Our study demonstrates that the phosphorylation of a single, critical PR65 amino acid (S401) by ATM fundamentally controls the DDR, and balances DSB repair quality, cell survival and growth by spatiotemporal PR65 nuclear-cytoplasmic shuttling mediated by the nuclear export receptor CRM1.

#Springwatch #WildMorningswithChris: Engaging With Nature via Social Media and Wellbeing During the COVID-19 Lockdown

It is widely understood that nature engagement benefits human wellbeing. Such benefits have been found for real as well as virtual engagements. However, little is known about the role of nature-based videos in social media on wellbeing. With COVID-19 restrictions limiting people's direct engagement with natural environments, this study critically examined people's reactions to nature videos posted on Facebook during the first UK COVID-19 lockdown in 2020. Data consisted of comments on videos containing highlights from the British Broadcasting Corporation's (BBC) Springwatch 2020 television series, and from a UK television presenter and naturalist's (Chris Packham) livestream videos, posted on Facebook from March to July, 2020. Looking at the quantitative profile of a range of videos (i.e. views, likes and shares) and a detailed analysis of the 143,265 comments using thematic analysis, three major themes were generated as: (1) engaging with nature via social media is emotionally complicated, (2) cognitive and reflective reactions are generated from social media nature engagement and (3) engagement with nature-based social media as a mechanism for coping with stress during COVID-19. These findings inform understanding of how nature-related social media content and associated commentary have supported wellbeing throughout the ongoing pandemic and their importance as a means of continued support for wellbeing. 'We feel that the injection of wildlife into people's homes, particularly at this point, would be really valuable and uplifting'. - Chris Packham, 2020.

The development and validation of the Misophonia response scale

OBJECTIVE

Most current Misophonia scales are not validated, do not include both emotional and physiological responses to triggers, and/or focus only on auditory triggers. This research aimed to develop and validate a measure of the magnitude of the Misophonic response that addressed these omissions.

METHOD

Three studies were carried out with individuals with self-diagnosed Misophonia. In study 1, expert opinion and participants commented on initial items to determine both face and content validity. In study 2, scale structure, reliability, and convergent and discriminant validity were determined using correlations, principal component analysis (PCA), and reliability analysis. In study 3, factor structure was confirmed in another sample of participants using confirmatory factor analysis (CFA).

RESULTS

The final 22-item scale assesses the magnitude of responses to triggers across any sensory modality. There are three subscales (emotional, physiological, and participation in life), with three additional items measuring frequency of triggers, avoidance of triggers, and time taken to recover from the triggers. The final scale showed suitable discriminant and convergent validity, with good internal consistency (Cronbach's alphas range 0.77 to 0.89). The three-component solution extracted using PCA explained 53.97% of variance, with all items loading between 0.45 and 0.84. The structure was confirmed with CFA (χ² = 269.01, p < .001; CFI = 0.96; TLI = 0.96 and RMSEA = 0.045 (CI 0.037-0.053).

CONCLUSION

The Misophonia Response Scale, which is valid and reliable, will facilitate understanding of Misophonia as it is short and easy to use for self-report in research.

Interventions to change purchasing behaviour in supermarkets: a systematic review and intervention content analysis

This systematic review and intervention content analysis used behavioural science frameworks to characterise content and function of interventions targeting supermarket shoppers' purchasing behaviour, and explore if coherence between content and function was linked to intervention effectiveness. Study eligibility: in-store interventions (physical supermarkets) with control conditions, targeting objectively measured food and/or non-alcoholic drink purchases, published in English (no date restrictions). Eleven electronic databases were searched; reference lists of systematic reviews were hand-searched. Methodological quality was assessed using the GATE checklist. A content analysis was performed to characterise intervention content and function, and theoretical coherence between these, using the Behaviour Change Wheel, Behaviour Change Techniques Taxonomy, and Typology of Interventions in Proximal Physical Micro-Environments (TIPPME). Forty-six articles (49 interventions) met inclusion criteria; 26 articles (32 interventions) were included in the content analysis. Twenty behaviour change techniques (BCTs), and four TIPPME intervention types were identified; three BCTs ('Prompts/cues', 'Material incentive', and 'Material reward') were more common in effective interventions. Nineteen interventions solely employed theoretically appropriate BCTs. Theoretical coherence between BCTs and intervention functions was more common in effective interventions. Effective interventions included price promotions and/or in-store merchandising. Future research should explore the effect of specific BCTs using factorial study designs. PROSPERO Registration: CRD42017071065.

Examining the Effect of Context, Beliefs, and Values on UK Farm Veterinarians' Antimicrobial Prescribing: A Randomized Experimental Vignette and Cross-Sectional Survey

Antimicrobial resistance (AMR) is a pressing threat to public and animal health. There is evidence that antimicrobial prescribing and stewardship behaviors by veterinarians (vets) are influenced by non-clinical factors, such as psychological, social, and environmental factors. This study explored the role of context, beliefs, and values on vets' antimicrobial prescribing decisions. UK-based practicing farm vets (n = 97) were recruited to an online study. Using an experimental vignette methodology, vets were randomly assigned across four conditions, to examine the effects of different contexts (pressure on farm economics, the farmer, or the vet-farmer relationship, compared to a control condition) on vets' likelihood of prescribing antibiotics. Vets' beliefs about different groups' responsibility for causing and preventing AMR and vets' values were also measured. Key findings were that context alone, values, and beliefs about groups' responsibilities for causing AMR were not predictive of vets' likelihood of prescribing antibiotics. However, vets' beliefs about groups' responsibilities for preventing AMR were predictive of an increased likelihood of prescribing antibiotics, when vets were exposed to the experimental condition of the vignette in which the vet-farmer relationship was under pressure. Farm vets also believed that different groups have different levels of responsibility for causing and preventing AMR. Results should be interpreted cautiously, given the smaller than planned for sample size, and the possibility for both false negatives and false positives. Further research is needed to explore how these findings could inform antimicrobial stewardship interventions in veterinary medicine.

The role of emotions and injunctive norms in breastfeeding: a systematic review and meta-analysis

Breastfeeding has many known benefits, but rates vary globally. We propose two main reasons why psychological theory and interventions have not been successful to date in explaining breastfeeding behaviours. Specifically, prior research underestimates the importance of (1) specific emotions and (2) wider injunctive influences (i.e., societal and moral norms about what women feel they ought to be doing) in the breastfeeding experience. Therefore, we conducted a systematic review of quantitative, qualitative, and mixed-methods studies that explored whether injunctive norms and/ or specific emotions are associated with breastfeeding behaviours (i.e., intentions, initiation and duration). Seventy-two papers were included in this review; data were extracted and quality appraisals conducted for all included studies. A meta-analysis of effect sizes was performed with the quantitative data. A convergent qualitative synthesis of the data was conducted, resulting in the following line of argument: Breastfeeding is a social behaviour and not a personal/individual behaviour. From this line of argument, three themes with associated sub-themes were developed, highlighting the importance of both specific emotions and injunctive norms on breastfeeding behaviours. These influences are discussed in relation to both theoretical and practical implications, as well as future research.

Shared Goals, Different Barriers: A Qualitative Study of UK Veterinarians' and Farmers' Beliefs About Antimicrobial Resistance and Stewardship

Although much research has investigated the drivers of inappropriate antimicrobial prescribing in human medicine, equivalent research in veterinary medicine is in its infancy. This qualitative study used a critical incident approach to explore farm veterinarians' (vets) and farmers' beliefs about antimicrobial use and antimicrobial stewardship. Semi-structured interviews were conducted with 13 vets and 12 farmers in the UK, who worked mostly with beef cattle, dairy cattle and sheep, but a minority also worked with pigs or poultry. An inductive thematic analysis was conducted to explore how vets and farmers understood their responsibilities toward stewardship and antimicrobial resistance (AMR) and to identify key similarities and differences between the professions. The analysis generated four themes: "A shared conflict between ideals and behaviour," "Barriers to stewardship: the vets' perspective," "Barriers to stewardship: the farmers' perspective," and "A shared ambivalence: ownership vs. other-blaming." Vets and farmers demonstrated good understanding of stewardship but their treatment decisions are not always aligned to stewardship principles. Various barriers to improving antimicrobial stewardship were discussed by vets and farmers, but they placed differing emphasis on specific barriers. Faced with these barriers and an awareness that antimicrobial usage is not always aligned to stewardship principles, vets and farmers expressed frustration and a sense of ambivalence toward stewardship, and also engaged in other-blaming for the problem of AMR. In conclusion, vets and farmers in this study seem motivated to be antimicrobial stewards but feel challenged by the day-to-day reality of their jobs; they experience ambivalence toward their responsibilities for AMR, which may negatively impact their motivation to always act as antimicrobial stewards. Successfully tackling AMR will require change at the individual-, group-, and societal-level. Future interventions to improve antimicrobial usage in livestock farming could be situated within a social ecological framework, where other-blaming between professions is seen as a result of the interplay between psychological and contextual factors. Other-blaming could be reduced using a social identity approach; a common ingroup identity could be created by encouraging vets and farmers to focus on their common goal, namely a shared desire to promote animal welfare through optimal antimicrobial stewardship.

Exploring the psychological health of emergency dispatch centre operatives: a systematic review and narrative synthesis

Background

The study objective was to investigate and synthesize available evidence relating to the psychological health of Emergency Dispatch Centre (EDC) operatives, and to identify key stressors experienced by EDC operatives.

Methods

Eight electronic databases (Embase, PubMed, Medline, CINAHL, PsycInfo, PsycArticles, The Psychology and Behavioural Sciences Collection, and Google Scholar) were searched. All study designs were included, and no date limits were set. Studies were included if they were published in English, and explored the psychological health of any EDC operatives, across fire, police, and emergency medical services. Studies were excluded if they related solely to other emergency workers, such as police officers or paramedics. Methodological quality of included studies was assessed using checklists adapted from the Critical Appraisal Skills Programme. A narrative synthesis was conducted, using thematic analysis.

Results

A total of 16 articles were included in the review. Two overarching themes were identified during the narrative synthesis: ‘Organisational and Operational Factors’ and ‘Interactions with Others’. Stressors identified included being exposed to traumatic calls, lacking control over high workload, and working in under-resourced and pressured environments. Lack of support from management and providing an emotionally demanding service were additional sources of stress. Peer support and social support from friends and family were helpful in managing work-related stress.

Discussion

EDC operatives experience stress as a result of their work, which appears to be related to negative psychological health outcomes. Future research should explore the long-term effects of this stress, and the potential for workplace interventions to alleviate the negative impacts on psychological health.

PROSPERO Registration Number

CRD42014010806.

Mutation of the BRCA1 SQ-cluster results in aberrant mitosis, reduced homologous recombination, and a compensatory increase in non-homologous end joining

Mutations in the breast cancer susceptibility 1 (BRCA1) gene are catalysts for breast and ovarian cancers. Most mutations are associated with the BRCA1 N- and C-terminal domains linked to DNA double-strand break (DSB) repair. However, little is known about the role of the intervening serine-glutamine (SQ) - cluster in the DNA damage response beyond its importance in regulating cell cycle checkpoints. We show that serine-to-alanine alterations at critical residues within the SQ-cluster known to be phosphorylated by ATM and ATR result in reduced homologous recombination repair (HRR) and aberrant mitosis. While a S1387A BRCA1 mutant - previously shown to abrogate S-phase arrest in response to radiation - resulted in only a modest decrease in HRR, S1387A together with an additional alteration, S1423A (BRCA12P), reduced HRR to vector control levels and similar to a quadruple mutant also including S1457A and S1524A (BRCA14P). These effects appeared to be independent of PALB2. Furthermore, we found that BRCA14P promoted a prolonged and struggling HRR late in the cell cycle and shifted DSB repair from HRR to non-homologous end joining which, in the face of irreparable chromosomal damage, resulted in mitotic catastrophe. Altogether, SQ-cluster phosphorylation is critical for allowing adequate time for completing normal HRR prior to mitosis and preventing cells from entering G1 prematurely resulting in gross chromosomal aberrations.

The Influence of Hypoxia and pH on Bioluminescence Imaging of Luciferase-Transfected Tumor Cells and Xenografts

Bioluminescence imaging (BLI) is a relatively new noninvasive technology used for quantitative assessment of tumor growth and therapeutic effect in living animal models. BLI involves the generation of light by luciferase-expressing cells following administration of the substrate luciferin in the presence of oxygen and ATP. In the present study, the effects of hypoxia, hypoperfusion, and pH on BLI signal (BLS) intensity were evaluated in vitro using cultured cells and in vivo using a xenograft model in nude mice. The intensity of the BLS was significantly reduced in the presence of acute and chronic hypoxia. Changes in cell density, viability, and pH also affected BLS. Although BLI is a convenient non-invasive tool for tumor assessment, these factors should be considered when interpreting BLS intensity, especially in solid tumors that could be hypoxic due to rapid growth, inadequate blood supply, and/or treatment.

ATM kinase inhibition preferentially sensitizes p53-mutant glioma to ionizing radiation

PURPOSE

Glioblastoma multiforme (GBM) is the most lethal form of brain cancer with a median survival of only 12 to 15 months. Current standard treatment consists of surgery followed by chemoradiation. The poor survival of patients with GBM is due to aggressive tumor invasiveness, an inability to remove all tumor tissue, and an innate tumor chemo- and radioresistance. Ataxia-telangiectasia mutated (ATM) is an excellent target for radiosensitizing GBM because of its critical role in regulating the DNA damage response and p53, among other cellular processes. As a first step toward this goal, we recently showed that the novel ATM kinase inhibitor KU-60019 reduced migration, invasion, and growth, and potently radiosensitized human glioma cells in vitro.

EXPERIMENTAL DESIGN

Using orthotopic xenograft models of GBM, we now show that KU-60019 is also an effective radiosensitizer in vivo. Human glioma cells expressing reporter genes for monitoring tumor growth and dispersal were grown intracranially, and KU-60019 was administered intratumorally by convection-enhanced delivery or osmotic pump.

RESULTS

Our results show that the combined effect of KU-60019 and radiation significantly increased survival of mice 2- to 3-fold over controls. Importantly, we show that glioma with mutant p53 is much more sensitive to KU-60019 radiosensitization than genetically matched wild-type glioma.

CONCLUSIONS

Taken together, our results suggest that an ATM kinase inhibitor may be an effective radiosensitizer and adjuvant therapy for patients with mutant p53 brain cancers.

Abstract 437: ATM regulates glioma migration via MEK-ERK not AKT

Glioblastoma multiforme (GBM) is a lethal brain cancer with a life expectancy of only 12-15 months. Current standard treatment for GBM is surgery and chemoradiation. However, there are many difficulties when it comes to treating this aggressive brain cancer due to the inherent radio- and chemo-resistance. Consequently, there is a critical need for new therapeutic approaches to make radiation/chemotherapy more effective. Ataxia telangiectasia (A-T) patients are extremely sensitive to ionizing radiation. The protein mutated in A-T, ATM (A-T mutated), controls the cells’ response to radiation, referred to as the DNA damage response (DDR). ATM is a master protein kinase that targets many proteins during the DDR including regulators of cell cycle checkpoints, DNA repair, and apoptosis. In addition, without any radiation, ATM might regulate glioma dispersal. Using a highly specific inhibitor of the ATM kinase (ATMi), we recently showed that ATM regulates both the ERK and AKT signaling pathways and controls glioma cell migration and invasion in vitro. To take these studies further we have now used a genetic approach and knocked down ATM in human glioma cells. We have recapitulated our previous finding with an ATMi and shown that ATM knockdown glioma cells have reduced ability to migrate in vitro. In order to determine whether MEK/ERK and/or AKT regulate migration, human glioma cells were exposed to a MEK (PD0325901) or an AKT (MK-2266) inhibitor in a ‘scratch-assay’. We found that only the former compound affected migration in vitro. Hence, we have shown that ATM regulates glioma migration in vitro, perhaps via MEK/ERK. On the other hand, ATM might regulate invasion via AKT. The signaling relationship in vitro between ATM, ERK, and AKT is currently being investigated. Furthermore, ongoing studies will establish whether ERK and AKT signaling affect migration and invasion in vivo.

Citation Format: Jasmine L. Allen, Allison F. Wagner, Jason M. Beckta, James Watson, Sarah E. Golding, Kristoffer C. Valerie. ATM regulates glioma migration via MEK-ERK not AKT. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 437. doi:10.1158/1538-7445.AM2013-437

Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.

Abstract 1450: Targeting the ATM kinase as a novel strategy for radiosensitizing glioblastoma multiforme in mice

Glioblastoma multiforme (GBM) is the most lethal type of brain cancer. At best, mean survival is only 12-15 months so an improvement of current therapy is long overdue. Current treatment includes surgery and chemoradiation. The short survival of GBM patients is due, in part, to the innate radioresistance and vicious invasiveness of GBM. ATM, ataxia telangiectasia (A-T) mutated, would be an excellent target for radiosensitizing GBM because of its critical role in regulating the DNA damage response (DDR) and other cellular processes. As a first step towards this goal, we tested the ability of the novel ATM kinase inhibitor KU-60019 to radiosensitize GBM in mice. Using an orthotopic xenograft model of GBM, nude mice were implanted with human glioma cells expressing reporter genes for monitoring tumor growth and spread. KU-60019 was administered intra-cranially by convection-enhanced delivery or by osmotic pump. Imaging, survival, and signs of inhibiting the DDR using immunohistochemistry were used to characterize the effects of KU-60019 on tumor and normal brain. Our results show that compared with untreated, KU-60019 alone, or radiation alone treated mice, the combined effect of KU-60019 and radiation significantly increased survival at least 2-fold and sometimes even cured the animals. Multiple glioma cell lines with varied genetic backgrounds are currently being tested. Altogether, our results show that KU-60019 is able to overcome GBM radioresistance, a major obstacle in the treatment of GBM, and significantly prolong the survival of animals. Thus, an ATM kinase inhibitor may have great potential as adjuvant therapy in the clinic.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1450. doi:1538-7445.AM2012-1450

Dynamic inhibition of ATM kinase provides a strategy for glioblastoma multiforme radiosensitization and growth control

Glioblastoma multiforme (GBM) is notoriously resistant to treatment. Therefore, new treatment strategies are urgently needed. ATM elicits the DNA damage response (DDR), which confers cellular radioresistance; thus, targeting the DDR with an ATM inhibitior (ATMi) is very attractive. Herein, we show that dynamic ATM kinase inhibition in the nanomolar range results in potent radiosensitization of human glioma cells, inhibits growth and does not conflict with temozolomide (TMZ) treatment. The second generation ATMi analog KU-60019 provided quick, reversible and complete inhibition of the DDR at sub-micromolar concentrations in human glioblastoma cells. KU-60019 inhibited the phosphorylation of the major DNA damage effectors p53, H2AX and KAP1 as well as AKT. Colony-forming radiosurvival showed that continuous exposure to nanomolar concentrations of KU-60019 effectively radiosensitized glioblastoma cell lines. When cells were co-treated with KU-60019 and TMZ, a slight increase in radiation-induced cell killing was noted, although TMZ alone was unable to radiosensitize these cells. In addition, without radiation, KU-60019 with or without TMZ reduced glioma cell growth but had no significant effect on the survival of human embryonic stem cell (hESC)-derived astrocytes. Altogether, transient inhibition of the ATM kinase provides a promising strategy for radiosensitizing GBM in combination with standard treatment. In addition, without radiation, KU-60019 limits growth of glioma cells in co-culture with human astrocytes that seem unaffected by the same treatment. Thus, inter-fraction growth inhibition could perhaps be achieved in vivo with minor adverse effects to the brain.

Mutations in the BRCT binding site of BRCA1 result in hyper-recombination

We introduced a K1702M mutation in the BRCA1 BRCT domain known to prevent the binding of proteins harboring pS-X-X-F motifs such as Abraxas-RAP80, BRIP1, and CtIP. Surprisingly, rather than impairing homologous recombination repair (HRR), expression of K1702M resulted in hyper-recombination coinciding with an accumulation of cells in S-G2 and no effect on nonhomologous end-joining. These cells also showed increased RAD51 and RPA nuclear staining. More pronounced effects were seen with a naturally occurring BRCT mutant (M1775R) that also produced elevated levels of ssDNA, in part co-localizing with RPA, in line with excessive DNA resection. M1775R induced unusual, thread-like promyelocytic leukemia (PML) nuclear bodies and clustered RPA foci rather than the typical juxtaposed RPA-PML foci seen with wild-type BRCA1. Interestingly, K1702M hyper-recombination diminished with a second mutation in the BRCA1 RING domain (I26A) known to reduce BRCA1 ubiquitin-ligase activity. Thesein vitro findings correlated with elevated nuclear RAD51 and RPA staining of breast cancer tissue from a patient with the M1775R mutation. Altogether, the disruption of BRCA1 (BRCT)-pS-X-X-F protein binding results in ubiquitination-dependent hyper-recombination via excessive DNA resection and the appearance of atypical PML-NBs. Thus, certain BRCA1 mutations that cause hyper-recombination instead of reduced DSB repair might lead to breast cancer.

DNA double-strand break - induced pro-survival signaling

Radiation and other types of DNA damaging agents induce a plethora of signaling events simultaneously originating from the nucleus, cytoplasm, and plasma membrane. As a result, this presents a dilemma when seeking to determine causal relationships and better insight into the intricacies of stress signaling. ATM plays critical roles in both nuclear and cytoplasmic signaling, of which, the DNA damage response (DDR) is the best characterized. We have recently created experimental conditions where the DNA damage signal alone can be studied while minimizing the influence from the extranuclear compartment. We have been able to document pro-survival and growth promoting signaling (via ATM-AKT-ERK) resulting from low levels of DSBs (equivalent to ≤2 Gy). More extensive DSBs (>2 Gy eq.) result in phosphatase-mediated ERK dephosphorylation, and thus shutdown of ERK signaling. In contrast, radiation does not result in such dephosphorylation even at very high doses. We propose that phosphatases are inactivated perhaps as a result of reactive oxygen species, which does not occur in response to 'pure' DNA damage. Our findings suggest that clinically relevant radiation doses, which are intended to halt tumor growth and induce cell death, are unable to inhibit tumor pro-survival signaling via ERK dephosphorylation.

ATM-dependent ERK signaling via AKT in response to DNA double-strand breaks

Ionizing radiation (IR) triggers many signaling pathways primarily originating from either damaged DNA or non-nuclear sources such as growth factor receptors. Thus, to study the DNA damage-induced signaling component alone by irradiation would be a challenge. To generate DNA double-strand breaks (DSBs) and minimize non-nuclear signaling, human cancer cells having bromodeoxyuridine (BrdU) - substituted DNA were treated with the photosensitizer Hoechst 33258 followed by long wavelength UV (UV-A) treatment (BrdU photolysis). BrdU photolysis resulted in well-controlled, dose- dependent generation of DSBs equivalent to radiation doses between 0.2 - 20 Gy, as determined by pulsed-field gel electrophoresis, and accompanied by dose-dependent ATM (ser-1981), H2AX (ser-139), Chk2 (thr-68), and p53 (ser-15) phosphorylation. Interestingly, low levels (≤ 2 Gy equivalents) of BrdU photolysis stimulated ERK phosphorylation whereas higher (> 2 Gy eq.) resulted in ERK dephosphorylation. ERK phosphorylation was ATM-dependent whereas dephosphorylation was ATM-independent. The ATM-dependent increase in ERK phosphorylation was also seen when DSBs were generated by transfection of cells with an EcoRI expression plasmid or by electroporation of EcoRI enzyme. Furthermore, AKT was critical for transmitting the DSB signal to ERK. Altogether, our results show that low levels of DSBs trigger ATM- and AKT-dependent ERK pro-survival signaling and increased cell proliferation whereas higher levels result in ERK dephosphorylation consistent with a dose-dependent switch from pro-survival to anti-survival signaling.

Abstract 3923: ATM and KAP1 are required for nonhomologous end-joining in transcriptionally active chromatin

The effect of ATM signaling on nonhomologous end joining (NHEJ) was investigated using a novel, chromosomally-integrated, viral vector that allows for inducing tandem I-SceI-mediated DNA double strand breaks (DSBs). The DSBs can then be analyzed for NHEJ repair events by fluorescence- and PCR-based methods. Using highly specific kinase inhibitors and this repair system, we show that inhibiting ATM reduces NHEJ by 80% in human U87 glioma cells. PCR products that span the repaired DSBs were analyzed by cleavage with a restriction enzyme that exclusively cuts the DNA repaired by high-fidelity repair. This analysis showed that the extent of high-fidelity repair was reduced by 40% when the ATM kinase was inhibited. KAP1 is a DNA damage-induced phosphorylation target of ATM that is linked to the modulation of chromatin structure. The ATM kinase inhibitor used in our studies blocks radiation-induced phosphorylation of KAP1 on serine 823/4. Knocking down KAP1 via shRNA had no effect on homologous recombination repair, but reduced NHEJ by 80%. Simultaneous treatment of cells with the ATM inhibitor and trichostatin A, a histone deacetylase inhibitor that promotes chromatin decondensation, abrogated the effect of the ATM inhibitor. These data are consistent with the hypothesis that ATM regulates DNA accessibility in chromatin. Together, these results suggest that ATM is critical for NHEJ of I-SceI DSBs and for high-fidelity repair of breaks within transcriptionally-active chromatin. The requirement for ATM in this system is likely a consequence of its signaling to chromatin modulating proteins that dynamically act on chromatin architecture surrounding DSBs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3923.

Dynamic dependence on ATR and ATM for double-strand break repair in human embryonic stem cells and neural descendants

The DNA double-strand break (DSB) is the most toxic form of DNA damage. Studies aimed at characterizing DNA repair during development suggest that homologous recombination repair (HRR) is more critical in pluripotent cells compared to differentiated somatic cells in which nonhomologous end joining (NHEJ) is dominant. We have characterized the DNA damage response (DDR) and quality of DNA double-strand break (DSB) repair in human embryonic stem cells (hESCs), and in vitro-derived neural cells. Resolution of ionizing radiation-induced foci (IRIF) was used as a surrogate for DSB repair. The resolution of γ-H2AX foci occurred at a slower rate in hESCs compared to neural progenitors (NPs) and astrocytes perhaps reflective of more complex DSB repair in hESCs. In addition, the resolution of RAD51 foci, indicative of active homologous recombination repair (HRR), showed that hESCs as well as NPs have high capacity for HRR, whereas astrocytes do not. Importantly, the ATM kinase was shown to be critical for foci formation in astrocytes, but not in hESCs, suggesting that the DDR is different in these cells. Blocking the ATM kinase in astrocytes not only prevented the formation but also completely disassembled preformed repair foci. The ability of hESCs to form IRIF was abrogated with caffeine and siRNAs targeted against ATR, implicating that hESCs rely on ATR, rather than ATM for regulating DSB repair. This relationship dynamically changed as cells differentiated. Interestingly, while the inhibition of the DNA-PKcs kinase (and presumably non-homologous endjoining [NHEJ]) in astrocytes slowed IRIF resolution it did not in hESCs, suggesting that repair in hESCs does not utilize DNA-PKcs. Altogether, our results show that hESCs have efficient DSB repair that is largely ATR-dependent HRR, whereas astrocytes critically depend on ATM for NHEJ, which, in part, is DNA-PKcs-independent.

Improved ATM kinase inhibitor KU-60019 radiosensitizes glioma cells, compromises insulin, AKT and ERK prosurvival signaling, and inhibits migration and invasion

Ataxia telangiectasia (A-T) mutated (ATM) is critical for cell cycle checkpoints and DNA repair. Thus, specific small molecule inhibitors targeting ATM could perhaps be developed into efficient radiosensitizers. Recently, a specific inhibitor of the ATM kinase, KU-55933, was shown to radiosensitize human cancer cells. Herein, we report on an improved analogue of KU-55933 (KU-60019) with K(i) and IC(50) values half of those of KU-55933. KU-60019 is 10-fold more effective than KU-55933 at blocking radiation-induced phosphorylation of key ATM targets in human glioma cells. As expected, KU-60019 is a highly effective radiosensitizer of human glioma cells. A-T fibroblasts were not radiosensitized by KU-60019, strongly suggesting that the ATM kinase is specifically targeted. Furthermore, KU-60019 reduced basal S473 AKT phosphorylation, suggesting that the ATM kinase might regulate a protein phosphatase acting on AKT. In line with this finding, the effect of KU-60019 on AKT phosphorylation was countered by low levels of okadaic acid, a phosphatase inhibitor, and A-T cells were impaired in S473 AKT phosphorylation in response to radiation and insulin and unresponsive to KU-60019. We also show that KU-60019 inhibits glioma cell migration and invasion in vitro, suggesting that glioma growth and motility might be controlled by ATM via AKT. Inhibitors of MEK and AKT did not further radiosensitize cells treated with KU-60019, supporting the idea that KU-60019 interferes with prosurvival signaling separate from its radiosensitizing properties. Altogether, KU-60019 inhibits the DNA damage response, reduces AKT phosphorylation and prosurvival signaling, inhibits migration and invasion, and effectively radiosensitizes human glioma cells.

Pro-survival AKT and ERK signaling from EGFR and mutant EGFRvIII enhances DNA double-strand break repair in human glioma cells

The epidermal growth factor receptor (EGFR) is frequently dysregulated in malignant glioma that leads to increased resistance to cancer therapy. Upregulation of wild type or expression of mutant EGFR is associated with tumor radioresistance and poor clinical outcome. EGFR variant III (EGFRvIII) is the most common EGFR mutation in malignant glioma. Radioresistance is thought to be, at least in part, the result of a strong cytoprotective response fueled by signaling via AKT and ERK that is heightened by radiation in the clinical dose range. Several groups including ours have shown that this response may modulate DNA repair. Herein, we show that expression of EGFRvIII promoted gamma-H2AX foci resolution, a surrogate for double-strand break (DSB) repair, and thus enhanced DNA repair. Conversely, small molecule inhibitors targeting EGFR, MEK, and the expression of dominant-negative EGFR (EGFR-CD533) significantly reduced the resolution of gamma-H2AX foci. When homologous recombination repair (HRR) and non-homologous end joining (NHEJ) were specifically examined, we found that EGFRvIII stimulated and CD533 compromised HRR and NHEJ, respectively. Furthermore, NHEJ was blocked by inhibitors of AKT and ERK signaling pathways. Moreover, expression of EGFRvIII and CD533 increased and reduced, respectively, the formation of phospho-DNA-PKcs and -ATM repair foci, and RAD51 foci and expression levels, indicating that DSB repair is regulated at multiple levels. Altogether, signaling from EGFR and EGFRvIII promotes both HRR and NHEJ that is likely a contributing factor towards the radioresistance of malignant gliomas.

Extracellular signal-related kinase positively regulates ataxia telangiectasia mutated, homologous recombination repair, and the DNA damage response

The accurate joining of DNA double-strand breaks by homologous recombination repair (HRR) is critical to the long-term survival of the cell. The three major mitogen-activated protein (MAP) kinase (MAPK) signaling pathways, extracellular signal-regulated kinase (ERK), p38, and c-Jun-NH(2)-kinase (JNK), regulate cell growth, survival, and apoptosis. To determine the role of MAPK signaling in HRR, we used a human in vivo I-SceI-based repair system. First, we verified that this repair platform is amenable to pharmacologic manipulation and show that the ataxia telangiectasia mutated (ATM) kinase is critical for HRR. The ATM-specific inhibitor KU-55933 compromised HRR up to 90% in growth-arrested cells, whereas this effect was less pronounced in cycling cells. Then, using well-characterized MAPK small-molecule inhibitors, we show that ERK1/2 and JNK signaling are important positive regulators of HRR in growth-arrested cells. On the other hand, inhibition of the p38 MAPK pathway generated an almost 2-fold stimulation of HRR. When ERK1/2 signaling was stimulated by oncogenic RAF-1, an approximately 2-fold increase in HRR was observed. KU-55933 partly blocked radiation-induced ERK1/2 phosphorylation, suggesting that ATM regulates ERK1/2 signaling. Furthermore, inhibition of MAP/ERK kinase (MEK)/ERK signaling resulted in severely reduced levels of phosphorylated (S1981) ATM foci but not gamma-H2AX foci, and suppressed ATM phosphorylation levels >85% throughout the cell cycle. Collectively, these results show that MAPK signaling positively and negatively regulates HRR in human cells. More specifically, ATM-dependent signaling through the RAF/MEK/ERK pathway is critical for efficient HRR and for radiation-induced ATM activation, suggestive of a regulatory feedback loop between ERK and ATM.

Double strand break repair by homologous recombination is regulated by cell cycle-independent signaling via ATM in human glioma cells

To investigate double strand break (DSB) repair and signaling in human glioma cells, we stably transfected human U87 (ATM(+), p53(+)) glioma cells with a plasmid having a single I-SceI site within an inactive green fluorescent protein (GFP) expression cassette, allowing for the detection of homologous recombination repair (HRR) by GFP expression. HRR and nonhomologous end joining (NHEJ) were also determined by PCR. DSB repair was first detected at 12 h postinfection with an adenovirus expressing I-SceI with repair reaching plateau levels between 24 and 48 h. Within this time frame, NHEJ predominated over HRR in the range of 3-50-fold. To assess the involvement of ATM in DSB repair, we first examined whether ATM was associated with the DSB. Chromatin immunoprecipitation showed that ATM was present at the site of the DSB as early as 18 h postinfection. In cells treated with caffeine, an inhibitor of ATM, HRR was reduced, whereas NHEJ was not. In support of this finding, GFP flow cytometry demonstrated that caffeine reduced HRR by 90% under conditions when ATM kinase activity was inhibited. Dominant-negative ATM expressed from adenovirus inhibited HRR by 45%, also having little to no effect on NHEJ. Furthermore, HRR was inhibited by caffeine in serum-starved cells arrested in G(0)/G(1), suggesting that ATM is also important for HRR outside of the S and G(2) cell cycle phases. Altogether, these results demonstrate that HRR contributes substantially to DSB repair in human glioma cells, and, importantly, ATM plays a critical role in regulating HRR but not NHEJ throughout the cell cycle.