Health conditions in spousal caregivers of people with dementia and their relationships with stress, caregiving experiences, and social networks: longitudinal findings from the IDEAL programme

OBJECTIVES

Longitudinal evidence documenting health conditions in spousal caregivers of people with dementia and whether these influence caregivers' outcomes is scarce. This study explores type and number of health conditions over two years in caregivers of people with dementia and subgroups based on age, sex, education, hours of care, informant-rated functional ability, neuropsychiatric symptoms, cognition of the person with dementia, and length of diagnosis in the person with dementia. It also explores whether over time the number of health conditions is associated with caregivers' stress, positive experiences of caregiving, and social networks METHODS: Longitudinal data from the IDEAL (Improving the experience of Dementia and Enhancing Active Life) cohort were used. Participants comprised spousal caregivers (n = 977) of people with dementia. Self-reported health conditions using the Charlson Comorbidity Index, stress, positive experiences of caregiving, and social network were assessed over two years. Mixed effect models were used RESULTS: On average participants had 1.5 health conditions at baseline; increasing to 2.1 conditions over two years. More health conditions were reported by caregivers who were older, had no formal education, provided 10 + hours of care per day, and/or cared for a person with more neuropsychiatric symptoms at baseline. More baseline health conditions were associated with greater stress at baseline but not with stress over time. Over two years, when caregivers' health conditions increased, their stress increased whereas their social network diminished DISCUSSION: Findings highlight that most caregivers have their own health problems which require management to avoid increased stress and shrinking of social networks.

Comorbid health conditions and their impact on social isolation, loneliness, quality of life, and well-being in people with dementia: longitudinal findings from the IDEAL programme

BACKGROUND

Most people with dementia have multiple health conditions. This study explores (1) number and type of health condition(s) in people with dementia overall and in relation to age, sex, dementia type, and cognition; (2) change in number of health conditions over two years; and (3) whether over time the number of health conditions at baseline is related to social isolation, loneliness, quality of life, and/or well-being.

METHODS

Longitudinal data from the IDEAL (Improving the experience of Dementia and Enhancing Active Life) cohort were used. Participants comprised people with dementia (n = 1490) living in the community (at baseline) in Great Britain. Health conditions using the Charlson Comorbidity Index, cognition, social isolation, loneliness, quality of life, and well-being were assessed over two years. Mixed effects modelling was used.

RESULTS

On average participants had 1.8 health conditions at baseline, excluding dementia; increasing to 2.5 conditions over two years. Those with vascular dementia or mixed (Alzheimer's and vascular) dementia had more health conditions than those with Alzheimer's disease. People aged ≥ 80 had more health conditions than those aged < 65 years. At baseline having more health conditions was associated with increased loneliness, poorer quality of life, and poorer well-being, but was either minimally or not associated with cognition, sex, and social isolation. Number of health conditions had either minimal or no influence on these variables over time.

CONCLUSIONS

People with dementia in IDEAL generally had multiple health conditions and those with more health conditions were lonelier, had poorer quality of life, and poorer well-being.

Trajectories of cognitive and perceived functional decline in people with dementia: Findings from the IDEAL programme

INTRODUCTION

Impaired cognition and instrumental activities of daily living (iADL) are key diagnostic features of dementia; however, few studies have compared trajectories of cognition and iADL.

METHODS

Participants from the IDEAL study comprised 1537, 1183, and 851 people with dementia, and 1277, 977, and 749 caregivers at baseline, 12 and 24 months, respectively. Addenbrooke's Cognitive Examination-III and Functional Activities Questionnaire were used to measure cognition and iADL, respectively. Scores were converted to deciles.

RESULTS

Self-rated iADL declined on average by -0.08 (-0.25, 0.08) decile points per timepoint more than cognition. Informant-rated iADL declined on average by -0.31 (-0.43, -0.18) decile points per timepoint more than cognition.

DISCUSSION

Cognition and self-rated iADL declined at a similar rate. Informant-rated iADL declined at a significantly greater rate than cognition. Therefore, either cognition and perceived iADL decline at different rates or informants overestimate increasing iADL difficulties compared to both cognition and self-ratings.

HIGHLIGHTS

Self-ratings of the degree of functional difficulties were consistent with cognition Decline in self-rated everyday activities was consistent with cognitive decline Informant-ratings of everyday activities declined more than cognition.

Living well with dementia: An exploratory matched analysis of minority ethnic and white people with dementia and carers participating in the IDEAL programme

OBJECTIVES

The increasing heterogeneity of the population of older people is reflected in an increasing number of people with dementia and carers drawn from minority ethnic groups. Data from the IDEAL study are used to compare indices of 'living well' among people with dementia and carers from ethnic minority groups with matched white peers.

METHODS

We used an exploratory cross-sectional case-control design to compare 'living well' for people with dementia and carers from minority ethnic and white groups. Measures for both groups were quality of life, life satisfaction, wellbeing, loneliness, and social isolation and, for carers, stress, relationship quality, role captivity and caring competence.

RESULTS

The sample of people with dementia consisted of 20 minority ethnic and 60 white participants and for carers 15 and 45 respectively. People with dementia from minority ethnic groups had poorer quality of life (-4.74, 95% CI: -7.98 to -1.50) and higher loneliness (1.72, 95% CI: 0.78-2.66) whilst minority ethnic carers had higher stress (8.17, 95% CI: 1.72-14.63) and role captivity (2.00, 95% CI: 0.43-3.57) and lower relationship quality (-9.86, 95% CI: -14.24 to -5.48) than their white peers.

CONCLUSION

Our exploratory study suggests that people with dementia from minority ethnic groups experience lower quality of life and carers experience higher stress and role captivity and lower relationship quality than their white peers. Confirmatory research with larger samples is required to facilitate analysis of the experiences of specific minority ethnic groups and examine the factors contributing to these disadvantages.

Dyadic influences on awareness of condition in people with dementia: findings from the IDEAL cohort

Introduction

The discrepancy between caregiver-ratings and self-ratings of abilities is commonly used to assess awareness in people with dementia. We investigated the contribution of caregiver and dyadic characteristics to the difference in perspective between caregiver-informants and people with dementia about difficulties experienced, when considering awareness of condition.

Methods

We conducted exploratory cross-sectional analyses using data from the IDEAL cohort. Participants were 1,038 community-dwelling people with mild-to-moderate dementia, and coresident spouse/partner caregivers. The Representations and Adjustment to Dementia Index (RADIX) checklist reporting difficulties commonly experienced in dementia was completed by 960 caregiver-informants and 989 people with dementia. Difference in scores was calculated for 916 dyads. Demographic information, cognition, informant-rated functional ability and neuropsychiatric symptoms were recorded for the person with dementia. Self-reported data were collected on mood, comorbidity, religion, importance of religion, relationship quality, and caregiver stress.

Results

For most dyads, caregivers reported more RADIX difficulties than people with dementia. Caregiver RADIX ratings were more closely associated with informant-rated functional ability and neuropsychiatric symptoms than with cognition. More RADIX difficulties and higher stress were reported by female caregivers. Greater RADIX difference was associated with more caregiver stress, and older age but less depression in people with dementia.

Conclusion

Few dyadic characteristics were important, but caregiver stress was higher where caregivers reported more RADIX difficulties and/or the difference in perspective was greater, whereas partners with dementia reported better mood. In addition to offering information about awareness of condition, the caregiver rating and difference in perspectives could indicate where more support is needed.

Resilience in caregivers of people with mild-to-moderate dementia: findings from the IDEAL cohort

OBJECTIVES

A novel model of resilience was tested in caregivers of people with mild-to-moderate dementia and was extended to explore whether including self-efficacy, optimism, and self-esteem improved its predictive value.

DESIGN

Cross-sectional.

SETTING

Data from the IDEAL cohort were used.

PARTICIPANTS

The study comprised 1222 caregivers of people with dementia.

MEASUREMENTS

A composite resilience score was calculated from five measures. Multivariable regressions were used to investigate factors associated with resilience.

RESULTS

Greater resilience was associated with being older, being male, and caregiving for older people with dementia. Greater resilience was also observed when people with dementia had fewer functional difficulties and/or fewer neuropsychiatric symptoms, there was a stronger dyadic relationship, and the caregiver had fewer social restrictions, less neuroticism, and greater perceived competence. Surprisingly, caregiver self-efficacy, optimism, and self-esteem were unrelated to resilience.

CONCLUSION

Caregivers of people with mild-to-moderate dementia generally scored well for resilience. Resilience was associated with both the personal characteristics of caregivers and level of care need among people with dementia. Future work is needed to determine whether the caregivers in this cohort appeared resilient because the care recipients had relatively low care needs and consequently placed fewer demands on caregiver well-being than would be the case where dementia is more advanced.

The associations between personality traits and quality of life, satisfaction with life, and well-being over time in people with dementia and their caregivers: findings from the IDEAL programme

BACKGROUND

Cross-sectional evidence indicates that certain personality traits may influence how well people with dementia and their caregivers are able to live alongside the condition. However, no studies to date have explored these associations longitudinally. The present study aimed to explore whether each of the Five-Factor personality traits were associated with change over two years in perceptions of 'living well' for people with dementia and their caregivers. 'Living well' was conceptualized as a composite of quality of life, satisfaction with life, and subjective well-being.

METHODS

Data were analyzed from 1487 people with dementia and 1234 caregivers who took part in the IDEAL cohort. Participants were categorized into low, medium, and high groups for each trait using stanine scores. Latent growth curve models investigated associations between these groups and 'living well' scores for each trait at baseline and at 12 and 24 months. Covariates included cognition in people with dementia and stress in caregivers. A Reliable Change Index was calculated against which to evaluate changes in 'living well' scores over time.

RESULTS

At baseline, neuroticism was negatively associated with 'living well' scores for people with dementia, while conscientiousness, extraversion, openness, and agreeableness were positively associated. For caregivers, neuroticism was negatively associated with 'living well' scores at baseline while conscientiousness and extraversion were positively associated. 'Living well' scores were mostly stable over time with no influence of personality traits on observed changes.

CONCLUSIONS

Findings suggest that personality traits, particularly neuroticism, have a meaningful impact on how people with dementia and caregivers rate their capability to 'live well' at baseline. Over time 'living well' scores for each personality trait group were largely stable. Studies utilizing longer follow-up periods and more appropriate measures of personality are needed to corroborate and extend the findings of the present study.

Longitudinal Predictors of Informant-Rated Involvement of People with Dementia in Everyday Decision-Making: Findings from the IDEAL Program

The extent to which people with dementia are involved in everyday decision-making is unclear. We explored informant-rated involvement of people with dementia in everyday decision-making over 2 years and whether functional, behavioral, and psychological factors related to the person with dementia and the caregiver explain variability in involvement of people with dementia in everyday decision-making. We used IDEAL data for 1182 people with dementia and their caregivers. Baseline mean score on the decision-making involvement scale was 31/45; it minimally declined over time. People with dementia who were female, single, and/or whose caregiver was younger had greater involvement in everyday decision-making than those without these characteristics. Better cognition, fewer functional difficulties, fewer neuropsychiatric symptoms, less caregiver stress, and better informant-rated relationship quality were associated with higher involvement in everyday decision-making. Cognitive and functional rehabilitation, and educational resources for caregivers, could prolong involvement of people with dementia in everyday decision-making.

Predictors of Awareness of Functional Ability in People with Dementia: The Contribution of Personality, Cognition, and Neuropsychiatric Symptoms - Findings from the IDEAL Program

INTRODUCTION

Discrepancy scores reflecting the difference between parallel ratings made by people living with dementia (PwD) in the mild-to-moderate stages and by their informants provide a way to investigate awareness of functional ability in relation to activities of daily living (ADL).

METHODS

Two measures of ADL (Functional Activities Questionnaire; Dependence Scale) were completed by 1,227 PwD and their informants in the IDEAL cohort study baseline assessment. Self-rated and informant-rated scores were used to calculate discrepancies, which were used as an indicator of awareness of functional ability. Smaller discrepancy scores were considered to reflect greater awareness on the part of PwD. PwD completed questionnaires on depression, personality, comorbidities, neuropsychiatric symptoms, and completed a measure of cognition. Informants provided ratings of stress. Univariable and multiple regressions were used to investigate factors related to ADL discrepancy.

RESULTS

A similar pattern of associations were found for both ADL discrepancy scores. Smaller discrepancy scores were associated with higher levels of depression, higher neuroticism, fewer neuropsychiatric symptoms, higher comorbidity, lower carer stress, and receipt of less than 1 hour of care per day from the informant.

DISCUSSION/CONCLUSION

There was a clear pattern of factors that were associated with greater awareness for both measures of functional ability. These factors associated with smaller discrepancy scores could be used to identify PwD who might benefit from targeted interventions to support their independence.

Profiles of social, cultural, and economic capital as longitudinal predictors of stress, positive experiences of caring, and depression among spousal carers of people with dementia

OBJECTIVE

We explored (1) social, cultural, and economic capital in spousal carers of people with dementia; (2) profiles of carers with different levels of capital; (3) whether the identified profiles differ in levels of stress and positive experiences of caring, and likelihood of depression over time.

METHODS

Baseline (2014-2016), 12-month, and 24-month follow-up data were analyzed for 984 coresident spousal carers of people with dementia. We assessed social, cultural, and economic capital, stress, positive experiences of caring, depression.

RESULTS

On average, carers reported infrequent social and cultural participation. Most carers were not socially isolated, trusted their neighbours, had education at least to age 16, and had an income aligned with the 2014 UK average. We identified four groups of carers with different levels of capital. Although on average stress was low, depression was infrequent, and positive experiences of caring were moderately frequent, the group of carers with lowest capital was the least stressed and reported the most positive experiences of caring over time. Compared to the two groups with better capital, those with poorer capital were more likely to be depressed over time.

CONCLUSION

Social, cultural, and economic resources may decrease likelihood of depression, but not stress, in carers of people with dementia.

'Living well' trajectories among family caregivers of people with mild-to-moderate dementia in the IDEAL cohort

Objectives

Understanding whether and how caregivers’ capability to “live well” changes over time, and the factors associated with change, could help target effective caregiver support.

Methods

We analyzed 3 time points (12 months apart) of Improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort data from coresident spouse caregivers of community-dwelling individuals who had mild-to-moderate dementia at baseline, using latent growth and growth mixture models. Capability to “live well” was derived from measures of quality of life, well-being, and satisfaction with life.

Results

Data from 995 spouse caregivers at Time 1, 780 at Time 2, and 601 at Time 3 were included. The mean “living well” score decreased slightly over time. We identified 3 classes of caregivers: one with higher baseline scores declining slightly over time (Stable; 66.8%), one with low baseline scores remaining stable (Lower Stable; 26.0%), and one with higher baseline scores showing marked decline (Declining; 7.2%). Scores on baseline measures differentiated the Lower Stable, but not the Declining, from the Stable class. Longitudinally, the Declining class was associated with care recipient cognitive decline and increasing hours providing care, as well as caregiver stress and depression. Findings were similar when caregivers with other kin relationships were included.

Discussion

The findings indicate the importance of prompt identification of, and support for, caregivers at risk of the declining capability to “live well” and may assist in identifying those caregivers who could benefit most from targeted support.

Longitudinal Trajectories of Quality of Life Among People With Mild-to-Moderate Dementia: A Latent Growth Model Approach With IDEAL Cohort Study Data

OBJECTIVES

We aimed to examine change over time in self-rated quality of life (QoL) in people with mild-to-moderate dementia and identify subgroups with distinct QoL trajectories.

METHODS

We used data from people with mild-to-moderate dementia followed up at 12 and 24 months in the Improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort study (baseline n = 1,537). A latent growth model approach examined mean change over time in QoL, assessed with the QoL-AD scale, and investigated associations of baseline demographic, cognitive, and psychological covariates with the intercept and slope of QoL. We employed growth mixture modeling to identify multiple growth trajectories.

RESULTS

Overall mean QoL scores were stable and no associations with change over time were observed. Four classes of QoL trajectories were identified: 2 with higher baseline QoL scores, labeled Stable (74.9%) and Declining (7.6%), and 2 with lower baseline QoL scores, labeled Stable Lower (13.7%) and Improving (3.8%). The Declining class had higher baseline levels of depression and loneliness, and lower levels of self-esteem and optimism, than the Stable class. The Stable Lower class was characterized by disadvantage related to social structure, poor physical health, functional disability, and low psychological well-being. The Improving class was similar to the Stable Lower class but had lower cognitive test scores.

DISCUSSION

Understanding individual trajectories can contribute to personalized care planning. Efforts to prevent decline in perceived QoL should primarily target psychological well-being. Efforts to improve QoL for those with poorer QoL should additionally address functional impairment, isolation, and disadvantage related to social structure.

A Comparison of Well-Being of Carers of People with Dementia and Their Ability to Manage Before and During the COVID-19 Pandemic: Findings from the IDEAL Study

BACKGROUND

Social restriction measures imposed to curb the spread of COVID-19 in the United Kingdom impacted on carers of people with dementia, limiting access to support services and increasing perceived burden of caring. Few studies have compared data collected both during and before the pandemic to examine the effect of these changes.

OBJECTIVE

To explore whether the COVID-19 pandemic affected the well-being of carers of people with dementia living in the community, and their ability to cope with their caring responsibilities.

METHODS

Analysis was conducted on two groups of carers who were enrolled in the IDEAL programme; the 'pre-pandemic group' (n = 312), assessed at two time points prior to the pandemic, and the 'pandemic group', assessed prior to and several months into the pandemic (n = 156). For the pre-pandemic group, carers were matched 2:1 to carers in the pandemic group on certain characteristics. Differences in change over time between the two groups on self-reported well-being, quality of life, coping, perceived competence, and role captivity, was investigated using mixed effect modelling.

RESULTS

Compared to the pre-pandemic group, those in the pandemic group appeared to cope better and had more stable self-rated competency and role captivity. They did not differ in terms of well-being or quality of life.

CONCLUSIONS

Despite reports of negative impacts on carers early in the pandemic, the findings suggest the pandemic had little negative longer-term impact on carers of people with dementia, and in fact they appeared to have a more positive attitude towards coping several months into the pandemic.

Characteristics of people living with undiagnosed dementia: findings from the CFAS Wales study

Background

Many people living with dementia remain undiagnosed, with diagnosis usually occurring long after signs and symptoms are present. A timely diagnosis is important for the wellbeing of the person living with dementia and the family, allowing them to plan and have access to support services sooner. The aim of this study was to identify demographic characteristics and neuropsychiatric symptoms associated with being undiagnosed, which may help clinicians be more aware of signs that could be indicative of early-stage or undetected dementia.

Methods

This cross-sectional study uses data from waves 1 and 2 (two years apart) of the Cognitive Function and Ageing Studies Wales (CFAS Wales). CFAS Wales participants were included who had a study assessment of dementia, as determined by the Automated Geriatric Examination for Computer Assisted Taxonomy (AGECAT) algorithm and by expert assessment, and who had had their primary care records checked for a clinical diagnosis of dementia. We identified 19 people with a diagnosis of dementia and 105 people living with undiagnosed dementia, and explored demographic characteristics and the presence or absence of a range of neuropsychiatric symptoms in the undiagnosed population using logistic regression.

Results

Findings suggest that people living with dementia who have better cognition, have more years of education, or live in more deprived areas are less likely to have a diagnosis. In terms of neuropsychiatric symptoms, depression and sleep problems were associated with being undiagnosed. Apathy was common across all people living with dementia, but those with a diagnosis were more likely to have severe apathy.

Conclusions

This study has clinical practice implications as the findings may help clinicians be more aware of characteristics and symptoms of people who are undiagnosed or who are at greater risk of remaining undiagnosed, enabling them to be more vigilant in picking up signs of dementia at an earlier stage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03086-4.

Trajectories of socio-emotional functioning in early-stage dementia: implications for the individual with dementia and their family carer

BACKGROUND AND OBJECTIVES

Changes in socio-emotional functioning in people living with dementia (PLWD) are common; however, little is known about the broader effects these may have on wellbeing. This study examined socio-emotional functioning over time and associations with the wellbeing of PLWD and their family carers.

METHOD

One hundred and one individuals with a diagnosis of dementia and their respective carers completed the Social Emotional Questionnaire (assessing emotion recognition, empathy, social relationships and social behaviour) alongside measures of dementia severity, cognition, mood, stress, and relationship quality. Sixty-six dyads were reassessed on the same measures at 12 months post-baseline, and 51 dyads again at 20 months post-baseline.

RESULTS

When rated by the PLWD, there was no change in socio-emotional functioning over time; however, carers reported a significant decline over time. For both carers and the PLWD, poorer wellbeing measures were indicative of worse socio-emotional functioning at Time 1, though only dementia type, quality of life and relationship quality impacted upon the trajectory of socio-emotional decline over time.

CONCLUSIONS

Changes in social and emotional functioning are evident early in the course of dementia and worsen within 20 months. Both carer characteristics and those of the PWLD affected reporting of social and emotional functioning. These data are useful for guiding the provision of appropriate education and care.

Impact of COVID-19 on carers of people with dementia in the community: Findings from the British IDEAL cohort

OBJECTIVE

Unpaid carers for people with dementia play a crucial role in society. Emerging evidence suggests the COVID-19 pandemic has negatively impacted on carers. This study sought to explore the impact of the COVID-19 pandemic on carers for community-dwelling people with dementia and compare responses with pre-pandemic data.

METHODS

Data were collected between September 2020 and April 2021 in England and Wales. Carers were identified from the Improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort and data were collected either through the telephone, video conferencing, or an online questionnaire. Responses from 242 carers were compared against benchmark data from the IDEAL cohort collected pre-pandemic. Analyses were conducted for the full sample of carers and spousal/partner carers only.

RESULTS

In total 48.8% of carers thought their healthcare needs were negatively affected during the pandemic. Compared with pre-pandemic data carers were more lonely and experienced less life satisfaction. There was little impact on carers' experience of caregiving, although carers felt trapped in their caregiving role. Carers were more optimistic and had higher social contact with relatives. There were changes in the methods carers used for contacting relatives and friends. Most carers coped very or fairly well during the pandemic. There was little difference in the experiences of spousal/partner carers and the full sample.

CONCLUSIONS

After a long period of providing care under pandemic conditions carers require additional support. This support needs to be focused on alleviating feelings of loneliness and increasing life satisfaction. Services need to consider how to improve access to health care, particularly resuming face-to-face appointments.

Minimal Impact of COVID-19 Pandemic on the Mental Health and Wellbeing of People Living With Dementia: Analysis of Matched Longitudinal Data From the IDEAL Study

OBJECTIVE

Research suggests a decline in the mental health and wellbeing of people with dementia (PwD) during the COVID-19 pandemic; however few studies have compared data collected pre-pandemic and during the pandemic. Moreover, none have compared this change with what would be expected due to dementia progression. We explored whether PwD experienced changes in mental health and wellbeing by comparing pre-pandemic and pandemic data, and drew comparisons with another group of PwD questioned on two occasions prior to the pandemic.

METHODS

Community-dwelling PwD enrolled in the IDEAL programme were split into two groups matched for age group, sex, dementia diagnosis, and time since diagnosis. Although each group was assessed twice, one was assessed prior to and during the pandemic (pandemic group; n = 115) whereas the other was assessed prior to the pandemic (pre-pandemic group; n = 230). PwD completed measures of mood, sense of self, wellbeing, optimism, quality of life, and life satisfaction.

RESULTS

Compared to the pre-pandemic group, the pandemic group were less likely to report mood problems, or be pessimistic, but more likely to become dissatisfied with their lives. There were no changes in continuity in sense of self, wellbeing, and quality of life.

DISCUSSION

Results suggest the pandemic had little effect on the mental health and wellbeing of PwD, with any changes observed likely to be consistent with expected rates of decline due to dementia. Although personal accounts attest to the challenges experienced, PwD appear to have been resilient to the impact of lockdown and social restrictions during the pandemic.

The Use and Costs of Paid and Unpaid Care for People with Dementia: Longitudinal Findings from the IDEAL Cohort

BACKGROUND

The drivers of costs of care for people with dementia are not well understood and little is known on the costs of care for those with rarer dementias.

OBJECTIVE

To characterize use and costs of paid and unpaid care over time in a cohort of people with dementia living in Britain. To explore the relationship between cohort members' demographic and clinical characteristics and service costs.

METHODS

We calculated costs of health and social services, unpaid care, and out-of-pocket expenditure for people with mild-to-moderate dementia participating in three waves of the IDEAL cohort (2014- 2018). Latent growth curve modelling investigated associations between participants' baseline sociodemographic and diagnostic characteristics and mean weekly service costs.

RESULTS

Data were available on use of paid and unpaid care by 1,537 community-dwelling participants with dementia at Wave 1, 1,199 at Wave 2, and 910 at Wave 3. In models of paid service costs, being female was associated with lower baseline costs and living alone was associated with higher baseline costs. Dementia subtype and caregiver status were associated with variations in baseline costs and the rate of change in costs, which was additionally influenced by age.

CONCLUSION

Lewy body and Parkinson's disease dementias were associated with higher service costs at the outset, and Lewy body and frontotemporal dementias with more steeply increasing costs overall, than Alzheimer's disease. Planners of dementia services should consider the needs of people with these relatively rare dementia subtypes as they may require more resources than people with more prevalent subtypes.

Psychological processes in adapting to dementia: Illness representations among the IDEAL cohort

How people understand and adapt to living with dementia may influence well-being. Leventhal’s Common Sense Model (CSM) of Self-Regulation provides a theoretical basis for exploring this process. We used cross-sectional and longitudinal data from 1,109 people with mild-to-moderate dementia in the Improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort. We elicited dementia representations (DRs) using the Representations and Adjustment to Dementia Index (RADIX), a validated measure based on the CSM, identified groups sharing distinct DR profiles, and explored predictors of group membership and associations with well-being, and whether problem-focused coping played a mediating role in these associations. We identified four DR classes: people who see the condition as a disease and adopt a diagnostic label; people who see the condition as a disease but refer to symptoms rather than a diagnostic label; those who see the condition as part of aging; and those who are unsure how to make sense of the condition. A fifth group did not acknowledge any difficulties. “Disease” representations were associated with better cognition and younger age, while “aging” and “no problem” representations were associated with better mood and well-being. The association with well-being remained stable over 24 months. There was limited partial support for a mediating role of problem-focused coping. Variations in DRs may reflect individual differences in the psychological processes involved in adjusting to dementia. DRs provide a framework for personalizing and tailoring both communications about dementia and interventions aimed at supporting people in coping with dementia. There is a need to debate what constitutes a positive DR and how its development might be encouraged.

Impact of COVID-19 on 'Living Well' with Mild-to-Moderate Dementia in the Community: Findings from the IDEAL Cohort

BACKGROUND

Negative impacts of the COVID-19 pandemic on people with dementia have been widely-documented, but most studies have relied on carer reports and few have compared responses to information collected before the pandemic.

OBJECTIVE

We aimed to explore the impact of the pandemic on community-dwelling individuals with mild-to-moderate dementia and compare responses with pre-pandemic data.

METHODS

During the second wave of the pandemic, we conducted structured telephone interviews with 173 people with dementia and 242 carers acting as informants, all of whom had previously participated in the IDEAL cohort. Where possible, we benchmarked responses against pre-pandemic data.

RESULTS

Significant perceived negative impacts were identified in cognitive and functional skills and ability to engage in self-care and manage everyday activities, along with increased levels of loneliness and discontinuity in sense of self and a decline in perceived capability to 'live well'. Compared to pre-pandemic data, there were lower levels of pain, depression, and anxiety, higher levels of optimism, and better satisfaction with family support. There was little impact on physical health, mood, social connections and relationships, or perceptions of neighborhood characteristics.

CONCLUSION

Efforts to mitigate negative impacts of pandemic-related restrictions and restore quality of life could focus on reablement to address the effects on participation in everyday activities, creating opportunities for social contact to reduce loneliness, and personalized planning to reconnect people with their pre-COVID selves. Such efforts may build on the resilience demonstrated by people with dementia and carers in coping with the pandemic.

Does awareness of condition help people with mild-to-moderate dementia to live well? Findings from the IDEAL programme

Background

People living with dementia vary in awareness of their abilities. We explored awareness of the condition and diagnosis in people with mild-to-moderate dementia, and how this relates to quality of life, well-being, life satisfaction, and caregiver stress.

Methods

This study was a cross-sectional exploratory analysis of data from the IDEAL cohort, which recruited people with dementia living at home and available caregivers from 29 research sites in Great Britain. Our study included 917 people with mild-to-moderate dementia and 755 carers. Low and high awareness groups were derived from self-reported responses to a dementia representation measure. Logistic regression was used to explore predictors of awareness of condition and diagnosis using demographic, cognitive, functional and psychological measures, and the relationship with quality of life, well-being and life satisfaction (‘living well’), and caregiver stress.

Results

There were 83 people with low awareness of their condition. The remaining 834 people showed some awareness and 103 of these had high awareness of their condition and diagnosis. Psychosocial factors were stronger predictors of awareness than cognitive and functional ability. Those with higher awareness reported lower mood, and lower scores on indices of living well as well as lower optimism, self-efficacy and self-esteem. Low awareness was more likely in those aged 80y and above, and living in more socially deprived areas. No relationship was seen between caregiver stress and awareness.

Conclusions

Awareness of the condition and diagnosis varies in people with mild-to-moderate dementia and is relevant to the capability to live well. Awareness should be considered in person-centered clinical care.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02468-4.

Dual Targeting of Chromatin Stability By The Curaxin CBL0137 and Histone Deacetylase Inhibitor Panobinostat Shows Significant Preclinical Efficacy in Neuroblastoma

PURPOSE

We investigated whether targeting chromatin stability through a combination of the curaxin CBL0137 with the histone deacetylase (HDAC) inhibitor, panobinostat, constitutes an effective multimodal treatment for high-risk neuroblastoma.

EXPERIMENTAL DESIGN

The effects of the drug combination on cancer growth were examined in vitro and in animal models of MYCN-amplified neuroblastoma. The molecular mechanisms of action were analyzed by multiple techniques including whole transcriptome profiling, immune deconvolution analysis, immunofluorescence, flow cytometry, pulsed-field gel electrophoresis, assays to assess cell growth and apoptosis, and a range of cell-based reporter systems to examine histone eviction, heterochromatin transcription, and chromatin compaction.

RESULTS

The combination of CBL0137 and panobinostat enhanced nucleosome destabilization, induced an IFN response, inhibited DNA damage repair, and synergistically suppressed cancer cell growth. Similar synergistic effects were observed when combining CBL0137 with other HDAC inhibitors. The CBL0137/panobinostat combination significantly delayed cancer progression in xenograft models of poor outcome high-risk neuroblastoma. Complete tumor regression was achieved in the transgenic Th-MYCN neuroblastoma model which was accompanied by induction of a type I IFN and immune response. Tumor transplantation experiments further confirmed that the presence of a competent adaptive immune system component allowed the exploitation of the full potential of the drug combination.

CONCLUSIONS

The combination of CBL0137 and panobinostat is effective and well-tolerated in preclinical models of aggressive high-risk neuroblastoma, warranting further preclinical and clinical investigation in other pediatric cancers. On the basis of its potential to boost IFN and immune responses in cancer models, the drug combination holds promising potential for addition to immunotherapies.

A G316A Polymorphism in the Ornithine Decarboxylase Gene Promoter Modulates MYCN-Driven Childhood Neuroblastoma

Simple Summary

Neuroblastoma is a devasting childhood cancer in which multiple copies (amplification) of the cancer-causing gene MYCN strongly predict poor outcome. Neuroblastomas are reliant on high levels of cellular components called polyamines for their growth and malignant behavior, and the gene regulating polyamine synthesis is called ODC1. ODC1 is often coamplified with MYCN, and in fact is regulated by MYCN, and like MYCN is prognostic of poor outcome. Here we studied a naturally occurring genetic variant or polymorphism that occurs in the ODC1 gene, and used gene editing to demonstrate the functional importance of this variant in terms of ODC1 levels and growth of neuroblastoma cells. We showed that this variant impacts the ability of MYCN to regulate ODC1, and that it also influences outcome in neuroblastoma, with the rarer variant associated with a better survival. This study addresses the important topic of genetic polymorphisms in cancer.

Abstract

Ornithine decarboxylase (ODC1), a critical regulatory enzyme in polyamine biosynthesis, is a direct transcriptional target of MYCN, amplification of which is a powerful marker of aggressive neuroblastoma. A single nucleotide polymorphism (SNP), G316A, within the first intron of ODC1, results in genotypes wildtype GG, and variants AG/AA. CRISPR-cas9 technology was used to investigate the effects of AG clones from wildtype MYCN-amplified SK-N-BE(2)-C cells and the effect of the SNP on MYCN binding, and promoter activity was investigated using EMSA and luciferase assays. AG clones exhibited decreased ODC1 expression, growth rates, and histone acetylation and increased sensitivity to ODC1 inhibition. MYCN was a stronger transcriptional regulator of the ODC1 promoter containing the G allele, and preferentially bound the G allele over the A. Two neuroblastoma cohorts were used to investigate the clinical impact of the SNP. In the study cohort, the minor AA genotype was associated with improved survival, while poor prognosis was associated with the GG genotype and AG/GG genotypes in MYCN-amplified and non-amplified patients, respectively. These effects were lost in the GWAS cohort. We have demonstrated that the ODC1 G316A polymorphism has functional significance in neuroblastoma and is subject to allele-specific regulation by the MYCN oncoprotein.

Dual targeting of polyamine synthesis and uptake in diffuse intrinsic pontine gliomas

Diffuse intrinsic pontine glioma (DIPG) is an incurable malignant childhood brain tumor, with no active systemic therapies and a 5-year survival of less than 1%. Polyamines are small organic polycations that are essential for DNA replication, translation and cell proliferation. Ornithine decarboxylase 1 (ODC1), the rate-limiting enzyme in polyamine synthesis, is irreversibly inhibited by difluoromethylornithine (DFMO). Herein we show that polyamine synthesis is upregulated in DIPG, leading to sensitivity to DFMO. DIPG cells compensate for ODC1 inhibition by upregulation of the polyamine transporter SLC3A2. Treatment with the polyamine transporter inhibitor AMXT 1501 reduces uptake of polyamines in DIPG cells, and co-administration of AMXT 1501 and DFMO leads to potent in vitro activity, and significant extension of survival in three aggressive DIPG orthotopic animal models. Collectively, these results demonstrate the potential of dual targeting of polyamine synthesis and uptake as a therapeutic strategy for incurable DIPG.

Inhibition of polyamine synthesis and uptake reduces tumor progression and prolongs survival in mouse models of neuroblastoma

Amplification of the MYCN oncogene is associated with an aggressive phenotype and poor outcome in childhood neuroblastoma. Polyamines are highly regulated essential cations that are frequently elevated in cancer cells, and the rate-limiting enzyme in polyamine synthesis, ornithine decarboxylase 1 (ODC1), is a direct transcriptional target of MYCN. Treatment of neuroblastoma cells with the ODC1 inhibitor difluoromethylornithine (DFMO), although a promising therapeutic strategy, is only partially effective at impeding neuroblastoma cell growth due to activation of compensatory mechanisms resulting in increased polyamine uptake from the surrounding microenvironment. In this study, we identified solute carrier family 3 member 2 (SLC3A2) as the key transporter involved in polyamine uptake in neuroblastoma. Knockdown of SLC3A2 in neuroblastoma cells reduced the uptake of the radiolabeled polyamine spermidine, and DFMO treatment increased SLC3A2 protein. In addition, MYCN directly increased polyamine synthesis and promoted neuroblastoma cell proliferation by regulating SLC3A2 and other regulatory components of the polyamine pathway. Inhibiting polyamine uptake with the small-molecule drug AMXT 1501, in combination with DFMO, prevented or delayed tumor development in neuroblastoma-prone mice and extended survival in rodent models of established tumors. Our findings suggest that combining AMXT 1501 and DFMO with standard chemotherapy might be an effective strategy for treating neuroblastoma.

Macrophage-Derived IL1β and TNFα Regulate Arginine Metabolism in Neuroblastoma

Neuroblastoma is the most common childhood solid tumor, yet the prognosis for high-risk disease remains poor. We demonstrate here that arginase 2 (ARG2) drives neuroblastoma cell proliferation via regulation of arginine metabolism. Targeting arginine metabolism, either by blocking cationic amino acid transporter 1 (CAT-1)-dependent arginine uptake in vitro or therapeutic depletion of arginine by pegylated recombinant arginase BCT-100, significantly delayed tumor development and prolonged murine survival. Tumor cells polarized infiltrating monocytes to an M1-macrophage phenotype, which released IL1β and TNFα in a RAC-alpha serine/threonine-protein kinase (AKT)-dependent manner. IL1β and TNFα established a feedback loop to upregulate ARG2 expression via p38 and extracellular regulated kinases 1/2 (ERK1/2) signaling in neuroblastoma and neural crest-derived cells. Proteomic analysis revealed that enrichment of IL1β and TNFα in stage IV human tumor microenvironments was associated with a worse prognosis. These data thus describe an immune-metabolic regulatory loop between tumor cells and infiltrating myeloid cells regulating ARG2, which can be clinically exploited. SIGNIFICANCE: These findings illustrate that cross-talk between myeloid cells and tumor cells creates a metabolic regulatory loop that promotes neuroblastoma progression.

Suppression of the ATP-binding cassette transporter ABCC4 impairs neuroblastoma tumour growth and sensitises to irinotecan in vivo

The ATP-binding cassette transporter ABCC4 (multidrug resistance protein 4, MRP4) mRNA level is a strong predictor of poor clinical outcome in neuroblastoma which may relate to its export of endogenous signalling molecules and chemotherapeutic agents. We sought to determine whether ABCC4 contributes to development, growth and drug response in neuroblastoma in vivo. In neuroblastoma patients, high ABCC4 protein levels were associated with reduced overall survival. Inducible knockdown of ABCC4 strongly inhibited the growth of human neuroblastoma cells in vitro and impaired the growth of neuroblastoma xenografts. Loss of Abcc4 in the Th-MYCN transgenic neuroblastoma mouse model did not impact tumour formation; however, Abcc4-null neuroblastomas were strongly sensitised to the ABCC4 substrate drug irinotecan. Our findings demonstrate a role for ABCC4 in neuroblastoma cell proliferation and chemoresistance and provide rationale for a strategy where inhibition of ABCC4 should both attenuate the growth of neuroblastoma and sensitise tumours to ABCC4 chemotherapeutic substrates.

Polyamine Antagonist Therapies Inhibit Neuroblastoma Initiation and Progression

PURPOSE

Deregulated MYC drives oncogenesis in many tissues yet direct pharmacologic inhibition has proven difficult. MYC coordinately regulates polyamine homeostasis as these essential cations support MYC functions, and drugs that antagonize polyamine sufficiency have synthetic-lethal interactions with MYC Neuroblastoma is a lethal tumor in which the MYC homologue MYCN, and ODC1, the rate-limiting enzyme in polyamine synthesis, are frequently deregulated so we tested optimized polyamine depletion regimens for activity against neuroblastoma.

EXPERIMENTAL DESIGN

We used complementary transgenic and xenograft-bearing neuroblastoma models to assess polyamine antagonists. We investigated difluoromethylornithine (DFMO; an inhibitor of Odc, the rate-limiting enzyme in polyamine synthesis), SAM486 (an inhibitor of Amd1, the second rate-limiting enzyme), and celecoxib (an inducer of Sat1 and polyamine catabolism) in both the preemptive setting and in the treatment of established tumors. In vitro assays were performed to identify mechanisms of activity.

RESULTS

An optimized polyamine antagonist regimen using DFMO and SAM486 to inhibit both rate-limiting enzymes in polyamine synthesis potently blocked neuroblastoma initiation in transgenic mice, underscoring the requirement for polyamines in MYC-driven oncogenesis. Furthermore, the combination of DFMO with celecoxib was found to be highly active, alone, and combined with numerous chemotherapy regimens, in regressing established tumors in both models, including tumors harboring highest risk genetic lesions such as MYCN amplification, ALK mutation, and TP53 mutation with multidrug resistance.

CONCLUSIONS

Given the broad preclinical activity demonstrated by polyamine antagonist regimens across diverse in vivo models, clinical investigation of such approaches in neuroblastoma and potentially other MYC-driven tumors is warranted. Clin Cancer Res; 22(17); 4391-404. ©2016 AACR.

Abstract 3808: MYCN coordinately regulates the entire polyamine gene pathway to drive polyamine biosynthesis in neuroblastoma, with expression of every synthetic and catabolic polyamine pathway gene being highly prognostic of clinical outcome

Background: Polyamines are highly regulated essential cations that are elevated in rapidly proliferating tissues. We have previously shown that the MYC/MYCN target ornithine decarboxylase (ODC1), rate-limiting for polyamine biosynthesis, is a therapeutic target for neuroblastoma (Hogarty et al, Cancer Res 2008; 68: 9735). We have also shown that targeting multiple steps in the polyamine pathway enhances therapeutic efficacy in complementary pre-clinical models (Haber et al, Adv Neurobl Res, 2012, OR 88). An international Phase I trial for refractory neuroblastoma, coordinated by the New Approaches to Neuroblastoma Treatment (NANT) consortium USA, will open shortly using ODC1 inhibition by high-dose difluoromethylornithine and SAT1 induction by celecoxib. We have now examined the prognostic impact of all polyamine pathway genes in a large cohort of neuroblastoma tumors.

Methods: Gene-expression profiles of 650 primary untreated neuroblastomas were analyzed for all polyamine pathway genes, and related to clinical outcome. Gene expression was evaluated by Real-Time PCR (RT-PCR) and correlated with MYCN levels in neuroblastoma cell lines. Activation and repression of polyamine genes by MYCN were analyzed by chromatin immunoprecipitation (ChIP). Polyamine gene promoters were cloned into luciferase reporter vectors and tested as a function of MYCN expression.

Results: Expression of all polyamine pathway genes was highly prognostic of neuroblastoma outcome. High levels of each synthetic gene and low levels of each catabolic gene predicted poor outcome. Multivariate analysis showed 6/11 genes retained independent prognostic significance following adjustment for MYCN, age and stage. In neuroblastoma cell lines, in the presence or absence of MYCN expression, RT-PCR analysis demonstrated a correlation of high MYCN with high biosynthetic polyamine gene expression, but an inverse correlation of high MYCN with low catabolic polyamine gene expression. ChIP assays confirmed that MYCN associates with biosynthetic gene promoters by binding to E-box sites in order to activate transcription. In contrast, MYCN binds the promoters of the catabolic genes in proximity to the transcription start sites by interacting with the Sp1 protein in order to repress transcription of these genes. Direct activation by MYCN of biosynthetic genes and down-regulation by MYCN of catabolic genes was confirmed by luciferase activity assays.

Conclusions: These results provide a remarkable demonstration of an oncogene coordinately regulating the expression of every gene in a metabolic pathway in order to drive cell proliferation. The findings highlight the importance of polyamines in neuroblastoma and identify target enzymes in addition to ODC1 for potential therapeutic intervention.

Citation Format: Murray D. Norris, Laura D. Gamble, Jayne Murray, Stefania Purgato, Giorgio Milazzo, Lesley J. Ashton, Andrei Oberthuer, Wendy B. London, Mike D. Hogarty, Mattias Fischer, David Ziegler, Glenn M. Marshall, Giovanni Perini, Michelle Haber. MYCN coordinately regulates the entire polyamine gene pathway to drive polyamine biosynthesis in neuroblastoma, with expression of every synthetic and catabolic polyamine pathway gene being highly prognostic of clinical outcome. [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 3808. doi:10.1158/1538-7445.AM2013-3808

Polyamine pathway inhibition as a novel therapeutic approach to treating neuroblastoma

Polyamines are highly regulated essential cations that are elevated in rapidly proliferating tissues, including diverse cancers. Expression analyses in neuroblastomas suggest that up-regulation of polyamine pro-synthetic enzymes and down-regulation of catabolic enzymes is associated with poor prognosis. Polyamine sufficiency may be required for MYCN oncogenicity in MYCN amplified neuroblastoma, and targeting polyamine homeostasis may therefore provide an attractive therapeutic approach. ODC1, an oncogenic MYCN target, is rate-limiting for polyamine synthesis, and is overexpressed in many cancers including neuroblastoma. Inhibition of ODC1 by difluoromethylornithine (DFMO) decreased tumor penetrance in TH-MYCN mice treated pre-emptively, and extended survival and synergized with chemotherapy in treating established tumors in both TH-MYCN and xenograft models. Efforts to augment DFMO activity, or otherwise maximally reduce polyamine levels, are focused on antagonizing polyamine uptake or augmenting polyamine export or catabolism. Since polyamine inhibition appears to be clinically well tolerated, these approaches, particularly when combined with chemotherapy, have great potential for improving neuroblastoma outcome in both MYCN amplified and non-MYCN amplified neuroblastomas.

Outcome of the p53-mediated DNA damage response in neuroblastoma is determined by morphological subtype and MYCN expression

BACKGROUND

MYCN oncogene amplification occurs in 20-25% of neuroblastoma and is associated with a poor prognosis. We previously reported that MYCN amplified (MNA) p53 wild-type neuroblastoma cell lines failed to G1 arrest in response to irradiation, but this could not be attributed to MYCN alone.

HYPOTHESIS

Genes co-amplified with MYCN and/or the predominant cell type, neuronal (N) or substrate adherent (S) phenotypes determine the downstream response to DNA damage in neuroblastoma cell lines.

METHODS

The MYCN amplicons of five MNA and two non-MNA cell line were mapped using 50K Single Nucleotide Polymorphism (SNP) arrays. One MNA (NBL-W) and one non-MNA neuroblastoma cell line (SKNSH) were sub-cloned into N and S-type cells and the p53 pathway investigated after irradiation induced DNA damage. To determine the role of p53 it was knocked down using siRNA.

RESULTS

No genes with a potential role in cell cycle regulation were consistently co-amplified in the MNA cell lines studied. High MYCN expressing NBLW-N cells failed to G1 arrest following irradiation and showed impaired induction of p21 and MDM2, whereas low MYCN expressing NBLW-S cells underwent a G1 arrest with induction of p21 and MDM2. Conversely N type cells underwent higher levels of apoptosis than S type cells. Following p53 knockdown in SHSY5Y N-type cells there was a decrease in apoptosis.

CONCLUSIONS

The downstream response to DNA damage in p53 wild-type neuroblastoma cell lines is p53 dependent, and determined both by the morphological sub-type and MYCN expression.

Abstract 612: MDMX expression is linked with MYCN amplification or expression in neuroblastoma, and sensitizes cells to MDM2-p53 antagonists

Introduction: Neuroblastoma is the most common solid extracranial pediatric tumor. Despite intense treatment, survival rates for patients with high risk disease remain below 40%. MYCN amplification is a major biomarker of poor prognosis and is an important oncogene that plays roles in driving proliferation and sensitizing to apoptosis. MDM2 is the principal negative regulator of p53 and is often hyperactive in neuroblastoma through either co-amplification with MYCN or inactivation of its negative regulator p14ARF. Increased activity of MDM2 may be an important mechanism by which MYCN amplified neuroblastomas evade MYCN mediated p53 dependent apoptosis. Since most neuroblastomas have wildtype p53, reactivation of p53 by MDM2-p53 antagonists is being investigated as a potential therapeutic approach. Like MDM2, MDMX is a negative regulator of p53 but whereas MDM2 regulates p53 stability and activity, MDMX regulates activity only. We hypothesised that MDMX removal or inhibition is necessary to fully activate p53 in neuroblastoma in response to MDM2-p53 antagonists.

Methods: MDMX expression in Tet21N MYCN regulatable cells and a panel of MYCN amplified and non-amplified neuroblastoma cell lines was determined by western blot. Knockdown of MDMX by siRNA was achieved in 3 MYCN amplified cell lines, followed by treatment with the MDM2-p53 antagonists Nutlin and MI-63. Induction of p53 responsive genes and apoptotic markers were observed by western blot and changes in cell cycle investigated using flow cytometry. Apoptosis was assessed by caspase activity.

Results: Activation of p53 was observed following Nutlin or MI-63 treatment in all 3 cell lines, as shown by a G1 arrest and/or induction of apoptosis. Following MDMX knockdown alone, an increase in p21 expression and/or apoptosis was observed suggesting that MDMX removal may be necessary to activate p53. However, MDMX knockdown and MDM2-p53 antagonist treatment resulted in no further effect on the cell cycle compared to Nutlin or MI-63 alone, and unexpectedly, a decrease in levels of apoptotic markers and caspase 3/7 activity (p&lt;0.001). We previously found that knockdown of MYCN resulted in decreased apoptosis after MDM2 inhibitor treatment (Gamble et al., submitted). Because a similar trend was observed with MDMX, we looked for a relationship between MYCN and MDMX. We found that MYCN+ Tet21N cells have increased MDMX expression compared to MYCN- cells, and MYCN amplified cell lines had increased MDMX expression compared to non-amplified cell lines.

Conclusions: Neuroblastoma cell lines are more resistant to MDM2-p53 antagonist mediated apoptosis following MDMX knockdown, suggesting that retention of MDMX activity is beneficial for response to MDM2-p53 antagonists in neuroblastoma. The link seen between MYCN and MDMX protein expression may therefore contribute to the sensitivity of MYCN amplified cells to MDM2-p53 antagonists.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 612. doi:10.1158/1538-7445.AM2011-612

p53 is a direct transcriptional target of MYCN in neuroblastoma

MYCN amplification occurs in approximately 25% of neuroblastomas, where it is associated with rapid tumor progression and poor prognosis. MYCN plays a paradoxical role in driving cellular proliferation and inducing apoptosis. Based on observations of nuclear p53 accumulation in neuroblastoma, we hypothesized that MYCN may regulate p53 in this setting. Immunohistochemical analysis of 82 neuroblastoma tumors showed an association of high p53 expression with MYCN expression and amplification. In a panel of 5 MYCN-amplified and 5 nonamplified neuroblastoma cell lines, and also in the Tet21N-regulatable MYCN expression system, we further documented a correlation between the expression of MYCN and p53. In MYCN-amplified neuroblastoma cell lines, MYCN knockdown decreased p53 expression. In Tet21N MYCN+ cells, higher levels of p53 transcription, mRNA, and protein were observed relative to Tet21N MYCN- cells. In chromatin immunoprecipitation and reporter gene assays, MYCN bound directly to a Myc E-Box DNA binding motif located close to the transcriptional start site within the p53 promoter, where it could initiate transcription. E-Box mutation decreased MYCN-driven transcriptional activation. Microarray analysis of Tet21N MYCN+/- cells identified several p53-regulated genes that were upregulated in the presence of MYCN, including MDM2 and PUMA, the levels of which were reduced by MYCN knockdown. We concluded that MYCN transcriptionally upregulates p53 in neuroblastoma and uses p53 to mediate a key mechanism of apoptosis.