Reversion and non-reversion mechanisms of resistance to PARP inhibitor or platinum chemotherapy in BRCA1/2-mutant metastatic breast cancer

BACKGROUND

Little is known about mechanisms of resistance to poly(adenosine diphosphate-ribose) polymerase inhibitors (PARPi) and platinum chemotherapy in patients with metastatic breast cancer and BRCA1/2 mutations. Further investigation of resistance in clinical cohorts may point to strategies to prevent or overcome treatment failure.

PATIENTS AND METHODS

We obtained tumor biopsies from metastatic breast cancer patients with BRCA1/2 deficiency before and after acquired resistance to PARPi or platinum chemotherapy. Whole exome sequencing was carried out on each tumor, germline DNA, and circulating tumor DNA. Tumors underwent RNA sequencing, and immunohistochemical staining for RAD51 foci on tumor sections was carried out for functional assessment of intact homologous recombination (HR).

RESULTS

Pre- and post-resistance tumor samples were sequenced from eight patients (four with BRCA1 and four with BRCA2 mutation; four treated with PARPi and four with platinum). Following disease progression on DNA-damaging therapy, four patients (50%) acquired at least one somatic reversion alteration likely to result in functional BRCA1/2 protein detected by tumor or circulating tumor DNA sequencing. Two patients with germline BRCA1 deficiency acquired genomic alterations anticipated to restore HR through increased DNA end resection: loss of TP53BP1 in one patient and amplification of MRE11A in another. RAD51 foci were acquired post-resistance in all patients with genomic reversion, consistent with reconstitution of HR. All patients whose tumors demonstrated RAD51 foci post-resistance were intrinsically resistant to subsequent lines of DNA-damaging therapy.

CONCLUSIONS

Genomic reversion in BRCA1/2 was the most commonly observed mechanism of resistance, occurring in four of eight patients. Novel sequence alterations leading to increased DNA end resection were seen in two patients, and may be targetable for therapeutic benefit. The presence of RAD51 foci by immunohistochemistry was consistent with BRCA1/2 protein functional status from genomic data and predicted response to later DNA-damaging therapy, supporting RAD51 focus formation as a clinically useful biomarker.

Clustered randomised controlled trial of two education interventions designed to increase physical activity and well-being of secondary school students: the MOVE Project

OBJECTIVE

To assess the effectiveness of 2 interventions in improving the physical activity and well-being of secondary school children.

DESIGN

A clustered randomised controlled trial; classes, 1 per school, were assigned to 1 of 3 intervention arms or a control group based on a 2×2 factorial design. The interventions were peer-mentoring and participative learning. Year 7 children (aged 11-12) in the peer-mentoring intervention were paired with year 9 children for 6 weekly mentoring meetings. Year 7 children in the participative learning arm took part in 6 weekly geography lessons using personalised physical activity and Global Positioning System (GPS) data. Year 7 children in the combined intervention received both interventions, with the year 9 children only participating in the mentoring sessions.

PARTICIPANTS

1494 year 7 students from 60 schools in the North of England took part in the trial. Of these, 43 students opted out of taking part in the evaluation measurements, 2 moved teaching group and 58 changed school. Valid accelerometry outcome data were collected for 892 students from 53 schools; and well-being outcome data were available for 927 students from 52 schools.

MAIN OUTCOME MEASURES

The primary outcomes were mean minutes of accelerometer-measured moderate-to-vigorous intensity physical activity per day, and well-being as evaluated by the KIDSCREEN-27 questionnaire. These data were collected 6 weeks after the intervention; a 12-month follow-up is planned.

RESULTS

No significant effects (main or interaction) were observed for the outcomes. However, small positive differences were found for both outcomes for the participative learning intervention.

CONCLUSIONS

These findings suggest that the 2 school-based interventions did not modify levels of physical activity or well-being within the period monitored. Change in physical activity may require more comprehensive individual behavioural intervention, and/or more system-based efforts to address wider environmental influences such as family, peers, physical environment, transport and educational policy.

TRIAL REGISTRATION NUMBER

ISRCTN82956355.

Malaria risk behaviours, socio-cultural practices and rural livelihoods in southern Tanzania: implications for bednet usage

Most malaria risk reduction strategies are firmly embedded in biomedical practices and public health perspectives. National and international programmes to 'control' malaria are particularly characterised by the promotion of public health interventions which converge on the disease vector, the malaria mosquito, notably through the use of indoor household spraying with insecticides, and the deployment of insecticide-treated bednets (ITNs). With convincing evidence for the effectiveness of ITNs in reducing the incidence of malaria, control programmes have emphasised the notion of 'scaling-up' bednet coverage. Much previous research on people's 'compliance' with bednet programmes has tended to focus on the quantification of bednet usage and on deriving explanations for 'non-compliance' based on household or individual indicators such as wealth, age, gender or educational level, or on climatic factors such as season and temperature. However, malaria risk behaviours are also rooted in wider aspects of local livelihoods, and socio-cultural beliefs and practices which interplay with the use and, crucially, non-use, of bednets. This paper draws on empirical data derived from in-depth, one-to-one semi-structured interviews, focus groups and participatory methods (mapping and diagramming) with participants in two villages in rural Tanzania to explore the nature of these practices and vulnerabilities, and their potential impact on malaria exposure risk. Participants included farmers and pastoralists, both men and women, as well as village 'officials'. By eliciting local understandings of malaria-related behaviours we explore how malaria risks are played out in people's everyday lives, and the circumstances and decision-making which underpin non-usage of bednets. Our findings reveal the importance of shifting sleeping patterns in response to livelihood needs and socio-cultural practices and events. These arrangements militate against the consistent and sustained use of the bednet which are called for by public health policies. In particular we demonstrate the importance of the spatial and temporal dimensions of farming practices and the role of conflict over access to shared land; the impact of livelihood activities on malaria risks for school-aged children; risk behaviours during 'special' socio-cultural events such as funeral ceremonies; and routine, outdoor activities around dawn and dusk and the gendered nature of these practices.

Advancing insights into methods for studying environment–health relationships: A multidisciplinary approach to understanding Legionnaires’ disease

Recent years have witnessed important advances in the analysis of spatially referenced health data. This paper uses GIS and point pattern modelling to address previously unanswered questions regarding the spatial epidemiology of Legionnaires' disease. We demonstrate a distance effect for proximity of residence to cooling towers; mixed support for a directional effect; and some evidence relating to multiple sources. In uncovering complex conceptual and technical problems in the spatial modelling of infection risk we also extended the limits of existing point pattern techniques. We advocate further multidisciplinary research to advance methodological developments for understanding spatial environment-health relationships.

Social implications of arsenic poisoning in Bangladesh

Besides its toxicity, groundwater arsenic contamination creates widespread social problems for its victims and their families in Bangladesh. There is, for instance, a tendency to ostracise arsenic-affected people, arsenicosis being thought of as a contagious disease. Within the community, arsenic-affected people are barred from social activities and often face rejection, even by their immediate family members. Women with visible arsenicosis symptoms are unable to get married and some affected housewives are divorced by their husbands. Children with symptoms are not sent to school in an effort to hide the problem. This paper employs mainly qualitative methods to interpret people's understandings about the toxic impact of groundwater arsenic poisoning on their social lives. Arsenic-affected patients in southwest Bangladesh were asked to determine their 'own priorities' in measuring arsenic toxicity on their social activities and to explore their perceptions about their own survival strategies. We found that patients' experiences reveal severe negative social impacts, and a sharp difference of perceptions about arsenic and social issues between arsenicosis patients and unaffected people.

Users’ perspectives on epidemiological, GIS and point pattern approaches to analysing environment and health data

Despite examples showing the usefulness of geographical information systems (GIS) and spatial point pattern analysis in health research, there remain barriers to their widespread use within health service settings. This paper explores potential users' views on the relative usefulness of such approaches for analysing spatially referenced environmental health data. Our findings indicate that researchers and practitioners do not always prefer the approach with which they are most familiar. In addition, there is a need for higher levels of understanding of, and confidence in, GIS and point pattern analysis techniques amongst health service professionals. The greatest need is for multi-disciplinary research which uses the most appropriate approach for each investigation, rather than that with which researchers are most familiar.

Public views on the links between air pollution and health in Northeast England

We investigated how public perceptions of the links between air pollution and health varied with contextual factors describing individuals and their locality. Information was collected via postal surveys on 2744 adults resident in five neighborhoods in Northeast England. Perceptions were compared by individual factors (health status, age, and gender) and locality factors (relative deprivation, proximity to industry and district-Teesside or Sunderland, with different amounts of heavy industry). There was relatively little variation in views about air pollution and health links between neighborhoods. The greatest contrasts were found when comparing those living near or further from industry and between the two districts. Any differences were related more to awareness of illness in the neighborhood thought to be affected by air pollution, rather than belief that a particular disease was linked to air pollution. Chronic illness status and age were sometimes found to be associated with perceptions of disease affected by air pollution, but gender and material deprivation were not central to differences in risk perceptions among the population studied. In understanding public perceptions about the links between air quality and health, research should focus on the characteristics of places as well as of people.

The spatial pattern of risk from arsenic poisoning: a Bangladesh case study

Arsenic poisoning in Bangladesh has been one of the biggest environmental health and social disasters of recent times. About seventy million people in Bangladesh are exposed to toxic levels of arsenic (0.05 mg/L) in drinking water. It is ironic that so many tubewells have been installed in recent times to provide drinking water that is safe from water-borne diseases but that the water pumped is contaminated with toxic levels of arsenic. Along with the clinical manifestations, some social problems have also emerged due to arsenic toxicity. Analysing the spatial risk pattern of arsenic in groundwater is the main objective of this paper. Establishing the extent of arsenic exposure to the people will facilitate an understanding of the health effects and estimating the population risk over the area. This paper seeks to explore the spatial pattern of arsenic concentrations in groundwater for analyzing and mapping 'problem regions' or 'risk zones' for composite arsenic hazard information by using GIS-based data processing and spatial analysis along with state-of-the-art decision-making techniques. Quantitative data along with spatial information were employed and analyzed for this paper.

Urban air quality in North-East England: exploring the influences on local views and perceptions

We set out to explore potential influences on public views about urban air quality in two different, but geographically close, districts in North-East England via a postal survey. The neighborhoods surveyed were chosen to contrast material deprivation, proximity to industry, and two districts (Teesside and Sunderland), and the respondents within them were contrasted by their gender, age, and illness status. The strongest influences on views about local air quality were found to be proximity to industry, residence in Teesside, and, to a lesser extent, age and illness status. This suggests that neighborhood characteristics play an important role in shaping public perceptions of air quality.

Analysing spatially referenced public health data: a comparison of three methodological approaches

In the analysis of spatially referenced public health data, members of different disciplinary groups (geographers, epidemiologists and statisticians) tend to select different methodological approaches, usually those with which they are already familiar. This paper compares three such approaches in terms of their relative value and results. A single public health dataset, derived from a community survey, is analysed by using 'traditional' epidemiological methods, GIS and point pattern analysis. Since they adopt different 'models' for addressing the same research question, the three approaches produce some variation in the results for specific health-related variables. Taken overall, however, the results complement, rather than contradict or duplicate each other.

Is it feasible to construct a community profile of exposure to industrial air pollution?

OBJECTIVE

An epidemiological investigation to assess the validity of residential proximity to industry as a measure of community exposure.

METHODS

19 Housing estates in Teesside (population 1991: 77 330) in north east England were grouped into zones: A=near; B=intermediate; C=further from industry. With residential proximity of socioeconomically matched populations as a starting point a historical land use survey, historical air quality reports, air quality monitoring, dispersion modelling data, and questionnaire data, were examined.

RESULTS

The populations in zones A, B, and C were similar for socioeconomic indicators and smoking history. Areas currently closest to industry had also been closest for most of the 20th century. Historical reports highlighted the influence of industrial emissions to local air quality, but it was difficult to follow spatial pollution patterns over time. Whereas contemporary NO(x) and benzene concentrations showed no geographical variation, dispersion modelling of emissions (116 industrial stacks, traffic, and domestic sources) showed a gradient associated with industry. The presumed exposure gradient of areas by proximity to industry (A>B>C) was evident for all of zone A and most of zones B and C.

CONCLUSIONS

It was feasible to assemble a picture of community exposure by integration of measurements from different sources. Proximity of residence was a reasonable surrogate for complex community exposure.

Does living near a constellation of petrochemical, steel, and other industries impair health?

OBJECTIVES

To investigate concern that local industrial air pollution in Teesside, England, was causing poor health, several areas there were compared with parts of the City of Sunderland.

METHODS

Populations in similar social and economic circumstances but varying in their proximity to major industries were compared. Study populations lived in 27 housing estates in Teesside and Sunderland, north east England, with some data from subsets of estates. The estates were aggregated into zones (designated as A, B, and C in Teesside where A is closest to and C furthest from industry, and S in Sunderland). Zone S provided a reference area. The hypothesis was that a health gradient both within Teesside (A > B > C) and between Teesside and Sunderland (ABC > S) would indicate a possible health effect of local industrial air pollution. Data presented were: mortality (1981-91) from 27 housing estates; population self completion questionnaire survey data (1993, 9115 subjects) from 15 housing estates; and general practitioner (GP) consultation data (1989-94) from 2201 subjects in 12 Teesside estates.

RESULTS

The populations in the four zones were comparable for indicators including smoking habits, residential histories, and unemployment. All cause and cause specific mortalities were high compared with England and Wales. Mortality in all Teesside zones (ABC) combined was mostly higher than in zone S. In people aged 0-64, lung cancer and respiratory disease showed gradients with highest mortality in areas closest to industry (A > B > C and ABC > S). The association was clearest for lung cancer in women (0-64 years old, trend across zones ABC, p = 0.07, directly standardised rate ratio relative to zone S was 169 (95% confidence interval (95% CI) 116-122)). There were no important, consistent gradients in the hypothesised direction between zones in consultation rates in general practice, and self reported respiratory and nonrespiratory health including asthma.

CONCLUSIONS

There was no clear evidence that living close to industry was associated with morbidity, including asthma, or for most measures of mortality. For lung cancer in women the gradients indicated a health effect of local industrial air pollution. In the age group 0-64 observed gradients in lung cancer in men and mortality from respiratory disease in men and women were consistent with the study hypothesis, although not significant. The reasons for the different patterns at different ages, and between men and women, remain a puzzle.

Cultural differences on three measures of dissociation in a substance abuse population

Scores on three measures of dissociation were compared between 48 African American and 48 Caucasian men being treated for substance abuse at a VA Medical Center. The three assessment instruments included the Dissociative Experience Scale, the Questionnaire of Experiences of Dissociation, and the North Carolina Index of Dissociation. Groups were matched with respect to age, education, marital status, number of previous treatments, IQ, employment status, history of childhood abuse, and psychological discomfort. In each case, the African-American group scored higher, with statistical significance being achieved on two of the three instruments. Potential implications of these findings were discussed and future research was suggested.

Asthma and factory emissions in northern England: addressing public concern by combining geographical and epidemiological methods

STUDY OBJECTIVE

The prevalence of asthma was assessed to investigate respiratory health effects of airborne emissions from a factory. A geographical information system allowed flexible definition of study areas in terms of their size, distance, and location in relation to the factory. The value of the approach for this type of investigation is focussed on.

SETTING

The factory is located in the south western part of a small market town in County Durham.

MEASUREMENTS AND MAIN RESULTS

A total of 1573 asthma cases were identified from general practitioner computerised repeat prescribing systems. Population denominators were defined from family health services authority patient registers. The area within 1 km and immediately to the north east of the factory had an age and sex standardised asthma prevalence 24% (confidence interval 4, 44%) in excess of the expected rate (p = 0.01). The increased prevalence was confined to middle aged and elderly adults living in the area between 0.5 and 1 km to the north east of the factory.

CONCLUSIONS

The value of combining the skills of geographers and epidemiologists in addressing public health issues is shown, particularly through the use of geographical information systems which proved powerful and effective.

Trauma symptoms in substance abusers with and without histories of childhood abuse

This study was designed to provide a prevalence rate of childhood abuse in patients being treated for alcohol and other drug problems, and to compare the extent of trauma symptoms that were present in substance abusers with and without childhood histories of physical, sexual, and emotional abuse. One hundred male veterans completed a standard test battery that included the Trauma Symptom Checklist and the Dissociative Experiences Scale. Clinical information pertaining to history of childhood abuse was obtained from the subjects' medical charts. Results demonstrated that 34% of the sample reported a history of childhood abuse. Although this group did achieve higher mean scores on all the scales, in comparison to the nonabused group, statistical significance was absent. Implications of these findings are discussed and future research is suggested.

Cytokines affect ion transport in primary cultured thick ascending limb of Henle's loop cells

Tumor necrosis factor-alpha (TNF) and interleukin-1 (IL-1) affect epithelial cell ion transport. However, the site of action along the nephron has not been elucidated fully for these cytokines. Thus, the effect of TNF and IL-1 on the ion transport function of primary cultured medullary thick ascending limb of Henle's loop (mTALH) cells was determined by measuring rubidium (86Rb) uptake. TNF, IL-1, and lipopolysaccharide (LPS), a known activator of cytokine production, inhibited 86Rb uptake by cultured mTALH cells after a 24-h incubation period but had no effect when incubated with the cells for 1 or 4 h. Furthermore, mTALH cells produced biologically active TNF after stimulation with LPS for 24 h, and the LPS-induced inhibition of 86Rb uptake was abolished in the presence of an anti-TNF antibody, suggesting that TNF produced by the mTALH cells acted in an autocrine manner to inhibit 86Rb uptake. The effects of LPS on 86Rb uptake also were inhibited by the cyclooxygenase inhibitor, indomethacin. As TNF increased prostaglandin E2 synthesis by cultured mTALH cells and as prostaglandin E2 also inhibited 86Rb uptake, LPS presumably inhibited 86Rb uptake by inducing a TNF-mediated increase in prostaglandin synthesis. These data demonstrate that a prostanoid produced by mTALH cells mediates the inhibitory effect of LPS and TNF on 86Rb uptake and imply that endogenous TNF inhibits ion fluxes in the mTALH via a prostaglandin-dependent mechanism.

Structural identification of cytochrome P450-dependent arachidonate metabolites formed by rabbit medullary thick ascending limb cells

The medullary thick ascending limb of Henle's loop (mTALH) contributes importantly to the regulation of extracellular fluid volume and composition and metabolizes arachidonic acid (AA) chiefly by a cytochrome P450 monooxygenase pathway. Rabbit mTALH cells, when incubated with radiolabeled [14C]AA, form products that segregate into two peaks designated P1 and P2 based on their reverse-phase high pressure liquid chromatography retention times. We have now definitively identified their chemical structures. mTALH cells, isolated from the rabbit outer medulla, were homogenized and incubated with [14C]AA in the presence of NADPH. The AA metabolites in P1 and P2 were identified by gas chromatographic-mass spectrometric methods, including fast atom bombardment, negative ion electron capture, and electron ionization. All mass spectrometric data, the lack of UV chromophores, and comparisons with authentic standards were consistent with P1 containing two principal components: 19-hydroxy-5,8,11,14 eicosatetraenoic acid (19-HETE) and 20 - hydroxy - 5,8,11,14 - eicosatetraenoic acid (20-HETE), P2 contained primarily 1,20-eicosa-5,8,11,14-tetraenedioic acid (20-COOH-AA). The biological properties of P1 and P2 were compared with those of the authentic standards of 19- and 20-HETE and 20-COOH-AA. P1 dose dependently relaxed precontracted mesenteric arterial rings, as did authentic (19S)- and (19R)-HETE, whereas 20-HETE relaxed at lower and contracted at higher concentrations. As P1 contained a mixture of 19- and 20-HETE, each of these AA metabolites presumably contributed to the vascular relaxation produced by P1. Neither P2 nor 20-COOH-AA exhibited vasoactivity, but each demonstrated a similar potency in inhibiting rabbit medullary Na(+)-K(+)-ATPase activity. As previously reported, P2 was a more potent inhibitor of Na(+)-K(+)-ATPase than P1. The lesser inhibitory activity of P1 presumably reflects the presence of similar amounts of 19-HETE, the least active metabolite, and 20-HETE, which resembles 20-COOH-AA in its capacity to inhibit Na(+)-K(+)-ATPase. Thus, the biological activity of the less polar peak, P1, can be accounted for by 19- and 20-HETE, and that of P2, by 20-COOH-AA.

Enzyme immunoassay for antibodies to Epstein-Barr virus nuclear antigen

An enzyme immunoassay that detects IgM and IgG antibodies to the nuclear antigen of Epstein-Barr virus (EBV) is evaluated. The EIA was compared with a rapid monoscreen (Immunoscan-IM) and an indirect fluorescent antibody procedure to determine the correlation of the new test with the current methodology. Among 73 patients tested for heterophilic antibody, 36 were positive; 25 of these had IgM antibodies to nuclear antigen. The sensitivity of the EIA compared to the mono screen was 69.4% and specificity was 97.3%. In comparison with fluorescence assays for IgG to the nuclear antigen, 94 patients were tested with 84 showing positivity by the fluorescent method. Among these, 80 were positive by EIA yielding a sensitivity and specificity of 95.2% and 90.0%, respectively. The EIA does not appear sensitive enough for replacement of the monoscreen but was a sensitive, cost-effective alternative to the indirect fluorescent antibody test.

The effect of hyperemia on spinal cord function after temporary thoracic aortic occlusion

Nineteen mongrel dogs had 30 minutes of thoracic aortic occlusion to determine the effects that blockade of the renin-angiotensin system may have on preserving spinal cord blood flow and function during a period of temporary spinal cord ischemia. Cross-clamping of the thoracic aorta causes renal ischemia and activates the renin-angiotensin system with resulting increased production of angiotensin II. Angiotensin II is a potent peripheral constrictor and elevated levels may constrict collateral spinal cord circulation. At the time of aortic cross-clamping, 10 dogs received 100 mg/kg of MK422 (intravenous enalapril maleate), a converting enzyme inhibitor, and nine animals served as controls. The blockade of the renin-angiotensin system had no preserving effects on spinal cord flow as measured by microspheres and on spinal cord function as graded with the Tarlov scale. However, the paraplegic animals all had significantly increased lower thoracic and lumbar spinal cord flows 30 minutes after clamp release when compared with those animals that remained neurologically intact. In conclusion, marked hyperemia occurring after a period of hypoperfusion may lead to spinal cord edema and compartment syndrome with resulting paraplegia.