Johnathan Watkins

Genomic scars as biomarkers of homologous recombination deficiency and drug response in breast and ovarian cancers

Poly (ADP-ribose) polymerase (PARP) inhibitors and platinum-based chemotherapies have been found to be particularly effective in tumors that harbor deleterious germline or somatic mutations in the BRCA1 or BRCA2 genes, the products of which contribute to the conservative homologous recombination repair of DNA double-strand breaks. Nonetheless, several setbacks in clinical trial settings have highlighted some of the issues surrounding the investigation of PARP inhibitors, especially the identification of patients who stand to benefit from such drugs. One potential approach to finding this patient subpopulation is to examine the tumor DNA for evidence of a homologous recombination defect. However, although the genomes of many breast and ovarian cancers are replete with aberrations, the presence of numerous factors able to shape the genomic landscape means that only some of the observed DNA abnormalities are the outcome of a cancer cell’s inability to faithfully repair DNA double-strand breaks. Consequently, recently developed methods for comprehensively capturing the diverse ways in which homologous recombination deficiencies may arise beyond BRCA1/2 mutation have used DNA microarray and sequencing data to account for potentially confounding features in the genome. Scores capturing telomeric allelic imbalance, loss of heterozygosity (LOH) and large scale transition score, as well as the total number of coding mutations are measures that summarize the total burden of certain forms of genomic abnormality. By contrast, other studies have comprehensively catalogued different types of mutational pattern and their relative contributions to a given tumor sample. Although at least one study to explore the use of the LOH scar in a prospective clinical trial of a PARP inhibitor in ovarian cancer is under way, limitations that result in a relatively low positive predictive value for these biomarkers remain. Tumors whose genome has undergone one or more events that restore high-fidelity homologous recombination are likely to be misclassified as double-strand break repair-deficient and thereby sensitive to PARP inhibitors and DNA damaging chemotherapies as a result of prior repair deficiency and its genomic scarring. Therefore, we propose that integration of a genomic scar-based biomarker with a marker of resistance in a high genomic scarring burden context may improve the performance of any companion diagnostic for PARP inhibitors.

Expression of somatostatin and dopamine 2 receptors in neuroendocrine tumours and the potential role for new biotherapies.

Introduction: Somatostatin and dopamine receptors are both G-protein-coupled receptors. Somatostatin receptor (SSTR) expression in neuroendocrine tumours has been well characterised, and there is evidence of dopamine receptor expression in neuroendocrine tumours. In this study, we examined expression of D2R, SSTR-2 and SSTR-5 using immunohistochemistry in patients with neuroendocrine tumours. Methods: Consecutive samples of formalin-fixed paraffin-embedded tumour tissue were available from 56 patients with a histologically confirmed diagnosis of neuroendocrine tumour (NET). The study population was divided into low-grade (n = 29), intermediate-grade (n = 18) and high-grade NET (n = 9). Immunohistochemical evaluation was performed for the expression of SSTR-2a, SSTR-5 and D2 receptors (D2R). Results: Both SSTR-2 and SSTR-5 were expressed in 100% of low-grade, 94.4% of intermediate-grade and 66.7% of high-grade NET. D2R was expressed in 93.1% of low-grade, 77.8% of intermediate-grade and 44.4% of high-grade tumours. Co-expression of all 3 receptors was present in 93.1% of low-grade tumours. There was an inverse correlation of SSTR-2 (r = –0.380, p < 0.005) and SSTR-5 (r = –0.472, p < 0.0001) with tumour grade. D2R was positively correlated with SSTR-2 (r = 0.269, p = 0.041) and SSTR-5 (r = 0.267, p = 0.045). Also, D2R expression was inversely correlated with grade of tumour (r = 0.395, p = 0.006). Octreoscan correlated with SSTR-2, SSTR-5 and D2R expression. Conclusion: D2R is expressed in the majority of low and intermediate grade tumours. It is co-expressed with SSTR-2 and SSTR-5 in the majority of cases. The advent of new chimeric molecules that bind both somatostatin and dopamine receptors may provide a new therapeutic option in the management of neuroendocrine patients.

Leukemic blasts program bone marrow adipocytes to generate a protumoral microenvironment

Despite currently available therapies, most patients diagnosed with acute myeloid leukemia (AML) die of their disease. Tumor-host interactions are critical for the survival and proliferation of cancer cells; accordingly, we hypothesize that specific targeting of the tumor microenvironment may constitute an alternative or additional strategy to conventional tumor-directed chemotherapy. Because adipocytes have been shown to promote breast and prostate cancer proliferation, and because the bone marrow adipose tissue accounts for up to 70% of bone marrow volume in adult humans, we examined the adipocyte-leukemia cell interactions to determine if they are essential for the growth and survival of AML. Using in vivo and in vitro models of AML, we show that bone marrow adipocytes from the tumor microenvironment support the survival and proliferation of malignant cells from patients with AML. We show that AML blasts alter metabolic processes in adipocytes to induce phosphorylation of hormone-sensitive lipase and consequently activate lipolysis, which then enables the transfer of fatty acids from adipocytes to AML blasts. In addition, we report that fatty acid binding protein-4 (FABP4) messenger RNA is upregulated in adipocytes and AML when in coculture. FABP4 inhibition using FABP4 short hairpin RNA knockdown or a small molecule inhibitor prevents AML proliferation on adipocytes. Moreover, knockdown of FABP4 increases survival in Hoxa9/Meis1-driven AML model. Finally, knockdown of carnitine palmitoyltransferase IA in an AML patient-derived xenograft model improves survival. Here, we report the first description of AML programming bone marrow adipocytes to generate a protumoral microenvironment.

Economic downturns, universal health coverage, and cancer mortality in high-income and middle-income countries, 1990-2010: a longitudinal analysis

BACKGROUND The global economic crisis has been associated with increased unemployment and reduced public-sector expenditure on health care (PEH). We estimated the effects of changes in unemployment and PEH on cancer mortality, and identified how universal health coverage (UHC) affected these relationships. METHODS For this longitudinal analysis, we obtained data from the World Bank and WHO (1990-2010). We aggregated mortality data for breast cancer in women, prostate cancer in men, and colorectal cancers in men and women, which are associated with survival rates that exceed 50%, into a treatable cancer class. We likewise aggregated data for lung and pancreatic cancers, which have 5 year survival rates of less than 10%, into an untreatable cancer class. We used multivariable regression analysis, controlling for country-specific demographics and infrastructure, with time-lag analyses and robustness checks to investigate the relationship between unemployment, PEH, and cancer mortality, with and without UHC. We used trend analysis to project mortality rates, on the basis of trends before the sharp unemployment rise that occurred in many countries from 2008 to 2010, and compared them with observed rates. RESULTS Data were available for 75 countries, representing 2.106 billion people, for the unemployment analysis and for 79 countries, representing 2.156 billion people, for the PEH analysis. Unemployment rises were significantly associated with an increase in all-cancer mortality and all specific cancers except lung cancer in women. By contrast, untreatable cancer mortality was not significantly linked with changes in unemployment. Lag analyses showed significant associations remained 5 years after unemployment increases for the treatable cancer class. Rerunning analyses, while accounting for UHC status, removed the significant associations. All-cancer, treatable cancer, and specific cancer mortalities significantly decreased as PEH increased. Time-series analysis provided an estimate of more than 40,000 excess deaths due to a subset of treatable cancers from 2008 to 2010, on the basis of 2000-07 trends. Most of these deaths were in non-UHC countries. INTERPRETATION Unemployment increases are associated with rises in cancer mortality; UHC seems to protect against this effect. PEH increases are associated with reduced cancer mortality. Access to health care could underlie these associations. We estimate that the 2008-10 economic crisis was associated with about 260,000 excess cancer-related deaths in the Organisation for Economic Co-operation and Development alone. FUNDING None.

PIM1 kinase regulates cell death, tumor growth and chemotherapy response in triple-negative breast cancer

Triple-negative breast cancers (TNBCs) have poor prognosis and lack targeted therapies. Here we identified increased copy number and expression of the PIM1 proto-oncogene in genomic data sets of patients with TNBC. TNBC cells, but not nonmalignant mammary epithelial cells, were dependent on PIM1 for proliferation and protection from apoptosis. PIM1 knockdown reduced expression of the anti-apoptotic factor BCL2, and dynamic BH3 profiling of apoptotic priming revealed that PIM1 prevents mitochondrial-mediated apoptosis in TNBC cell lines. In TNBC tumors and their cellular models, PIM1 expression was associated with several transcriptional signatures involving the transcription factor MYC, and PIM1 depletion in TNBC cell lines decreased, in a MYC-dependent manner, cell population growth and expression of the MYC target gene MCL1. Treatment with the pan–PIM kinase inhibitor AZD1208 impaired the growth of both cell line and patient-derived xenografts and sensitized them to standard-of-care chemotherapy. This work identifies PIM1 as a malignant-cell-selective target in TNBC and the potential use of PIM1 inhibitors for sensitizing TNBC to chemotherapy-induced apoptotic cell death.

Spatiotemporal organization of Aurora-B by APC/CCdh1 after mitosis coordinates cell spreading through FHOD1

Summary Spatiotemporal regulation of mitotic kinase activity underlies the extensive rearrangement of cellular components required for cell division. One highly dynamic mitotic kinase is Aurora-B (AurB), which has multiple roles defined by the changing localisation of the chromosome passenger complex (CPC) as cells progress through mitosis, including regulation of cytokinesis and abscission. Like other mitotic kinases, AurB is a target of the anaphase-promoting complex (APC/C) ubiquitin ligase during mitotic exit, but it is not known if APC/C-mediated destruction plays any specific role in controlling AurB activity. We have examined the contribution of the Cdh1 coactivator-associated APC/CCdh1 to the organization of AurB activity as cells exit mitosis and re-enter interphase. We report that APC/CCdh1-dependent proteolysis restricts a cell-cortex-associated pool of active AurB in space and time. In early G1 phase this pool of AurB is found at protrusions associated with cell spreading. AurB retention at the cortex depends on a formin, FHOD1, critically required to organize the cytoskeleton after division. We identify AurB phosphorylation sites in FHOD1 and show that phosphomutant FHOD1 is impaired in post-mitotic assembly of oriented actin cables. We propose that Cdh1 contributes to spatiotemporal organization of AurB activity and that organization of FHOD1 activity by AurB contributes to daughter cell spreading after mitosis.

Cigarette smoking and telomere length: A systematic review of 84 studies and meta-analysis

Background Cigarette smoking is a risk factor for ageing‐related disease, but its association with biological ageing, indicated by telomere length, is unclear. Methods We systematically reviewed evidence evaluating association between smoking status and telomere length. Searches were performed in MEDLINE (Ovid) and EMBASE (Ovid) databases, combining variation of keywords “smoking” and “telomere”. Data was extracted for study characteristics and estimates for association between smoking and telomere length. Quality of studies was assessed with a risk of bias score, and publication bias was assessed with a funnel plot. I2 test was used to observe heterogeneity. Meta‐analysis was carried out to compare mean difference in telomere length by smoking status, and a dose‐response approach was carried out for pack‐years of smoking and telomere length. A sensitivity analysis was carried out to examine sources of heterogeneity. Results A total of 84 studies were included in the review, and 30 among them were included in our meta‐analysis. Potential bias was addressed in half of included studies, and there was little evidence of small study bias. Telomere length was shorter among ever smokers compared to never smokers (summary standard mean difference [SMD]: −0.11 (95% CI −0.16 to −0.07)). Similarly, shorter telomere length was found among smokers compared to non‐smokers, and among current smokers compared to never or former smokers. Dose‐response meta‐analysis suggested an inverse trend between pack‐years of smoking and telomere length. However, heterogeneity among some analyses was observed. Conclusion Shorter telomeres among ever smokers compared to those who never smoked may imply mechanisms linking tobacco smoke exposure to ageing‐related disease. Graphical abstract Figure. No Caption available. HighlightsShorter telomere length is a marker for cellular ageing and chronic diseases.We systematically reviewed 84 primary studies on smoking and telomere length.Telomere length was shorter in ever smokers compared to never smokers.Among ever smokers, current smokers had shorter mean telomeres than former smokers.An inverse trend was indicated between pack‐years of smoking and telomere length.

Changes in government spending on healthcare and population mortality in the European union, 1995–2010: a cross-sectional ecological study

Objective Economic measures such as unemployment and gross domestic product are correlated with changes in health outcomes. We aimed to examine the effects of changes in government healthcare spending, an increasingly important measure given constrained government budgets in several European Union countries. Design Multivariate regression analysis was used to assess the effect of changes in healthcare spending as a proportion of total government expenditure, government healthcare spending as a proportion of gross domestic product and government healthcare spending measured in purchasing power parity per capita, on five mortality indicators. Additional variables were controlled for to ensure robustness of data. One to five year lag analyses were conducted. Setting and Participants European Union countries 1995–2010. Main outcome measures Neonatal mortality, postneonatal mortality, one to five years of age mortality, under five years of age mortality, adult male mortality, adult female mortality. Results A 1% decrease in government healthcare spending was associated with significant increase in all mortality metrics: neonatal mortality (coefficient −0.1217, p = 0.0001), postneonatal mortality (coefficient −0.0499, p = 0.0018), one to five years of age mortality (coefficient −0.0185, p = 0.0002), under five years of age mortality (coefficient −0.1897, p = 0.0003), adult male mortality (coefficient −2.5398, p = 0.0000) and adult female mortality (coefficient −1.4492, p = 0.0000). One per cent decrease in healthcare spending, measured as a proportion of gross domestic product and in purchasing power parity, was both associated with significant increases (p < 0.05) in all metrics. Five years after the 1% decrease in healthcare spending, significant increases (p < 0.05) continued to be observed in all mortality metrics. Conclusions Decreased government healthcare spending is associated with increased population mortality in the short and long term. Policy interventions implemented in response to the financial crisis may be associated with worsening population health.

Effects of health and social care spending constraints on mortality in England: a time trend analysis

Objective Since 2010, England has experienced relative constraints in public expenditure on healthcare (PEH) and social care (PES). We sought to determine whether these constraints have affected mortality rates. Methods We collected data on health and social care resources and finances for England from 2001 to 2014. Time trend analyses were conducted to compare the actual mortality rates in 2011–2014 with the counterfactual rates expected based on trends before spending constraints. Fixed-effects regression analyses were conducted using annual data on PES and PEH with mortality as the outcome, with further adjustments for macroeconomic factors and resources. Analyses were stratified by age group, place of death and lower-tier local authority (n=325). Mortality rates to 2020 were projected based on recent trends. Results Spending constraints between 2010 and 2014 were associated with an estimated 45 368 (95% CI 34 530 to 56 206) higher than expected number of deaths compared with pre-2010 trends. Deaths in those aged ≥60 and in care homes accounted for the majority. PES was more strongly linked with care home and home mortality than PEH, with each £10 per capita decline in real PES associated with an increase of 5.10 (3.65–6.54) (p<0.001) care home deaths per 100 000. These associations persisted in lag analyses and after adjustment for macroeconomic factors. Furthermore, we found that changes in real PES per capita may be linked to mortality mostly via changes in nurse numbers. Projections to 2020 based on 2009-2014 trend was cumulatively linked to an estimated 152 141 (95% CI 134 597 and 169 685) additional deaths. Conclusions Spending constraints, especially PES, are associated with a substantial mortality gap. We suggest that spending should be targeted on improving care delivered in care homes and at home; and maintaining or increasing nurse numbers.

Investigating the associations between adiposity, life course overweight trajectories, and telomere length

Obesity may accelerate ageing through chronic inflammation. To further examine this association, we assessed current adiposity, adiposity at early adulthood and life course overweight trajectories in relation to leukocyte telomere length (LTL). We included a total of 7,008 nationally representative U.S. residents and collected information on objectively measured body mass index (BMI), waist circumference and percent body fat. BMI at age 25 and overweight trajectories were assessed using self-reported history. Leukocyte telomere length (LTL) relative to a standard DNA reference (T/S ratio) was quantified by polymerase chain reaction (PCR). Linear regression models were used to examine the difference in LTL across adiposity measures at examination, BMI at age 25, and overweight trajectories. A 0.2% decrease in telomere length (95% CI:−0.3 to −0.07%) was observed for every kg/m2 increase in BMI, whereas a unit increase in waist circumference (cm) and percent body fat contributed to a 0.09% and 0.01% decrease in LTL, respectively. Higher BMI and being obese at age 25 contributed to lower LTL at older ages. Associations between weight loss through life course and LTL were observed, which further marked the importance of life course adiposity dynamics as a determinant of ageing.