The emerging relationship between metabolism and DNA repair.

The DNA damage response (DDR) consists of multiple specialized pathways that recognize different insults sustained by DNA and repairs them where possible to avoid the accumulation of mutations. While loss of activity of genes in the DDR has been extensively associated with cancer predisposition and progression, in recent years it has become evident that there is a relationship between the DDR and cellular metabolism. The activity of the metabolic pathways can influence the DDR by regulating the availability of substrates required for the repair process and the function of its players. Additionally, proteins of the DDR can regulate the metabolic flux through the major pathways such as glycolysis, tricarboxylic acid cycle (TCA) and pentose phosphate pathway (PPP) and the production of reactive oxygen species (ROS). This newly discovered connection bears great importance in the biology of cancer and represents a new therapeutic opportunity. Here we describe the nature of the relationship between DDR and metabolism and its potential application in the treatment of cancer. Keywords: DNA repair, metabolism, mitochondria.

3D Functional Genomics Screens Identify CREBBP as a Targetable Driver in Aggressive Triple-Negative Breast Cancer.

Triple-negative breast cancers (TNBC) are resistant to standard-of-care chemotherapy and lack known targetable driver gene alterations. Identification of novel drivers could aid the discovery of new treatment strategies for this hard-to-treat patient population, yet studies using high-throughput and accurate models to define the functions of driver genes in TNBC to date have been limited. Here, we employed unbiased functional genomics screening of the 200 most frequently mutated genes in breast cancer, using spheroid cultures to model in vivo-like conditions, and identified the histone acetyltransferase CREBBP as a novel tumor suppressor in TNBC. CREBBP protein expression in patient tumor samples was absent in 8% of TNBCs and at a high frequency in other tumors, including squamous lung cancer, where CREBBP-inactivating mutations are common. In TNBC, CREBBP alterations were associated with higher genomic heterogeneity and poorer patient survival and resulted in upregulation and dependency on a FOXM1 proliferative program. Targeting FOXM1-driven proliferation indirectly with clinical CDK4/6 inhibitors (CDK4/6i) selectively impaired growth in spheroids, cell line xenografts, and patient-derived models from multiple tumor types with CREBBP mutations or loss of protein expression. In conclusion, we have identified CREBBP as a novel driver in aggressive TNBC and identified an associated genetic vulnerability in tumor cells with alterations in CREBBP and provide a preclinical rationale for assessing CREBBP alterations as a biomarker of CDK4/6i response in a new patient population. SIGNIFICANCE: This study demonstrates that CREBBP genomic alterations drive aggressive TNBC, lung cancer, and lymphomas and may be selectively treated with clinical CDK4/6 inhibitors.

Real-time ex vivo perfusion of human lymph nodes invaded by cancer (REPLICANT): a feasibility study.

Understanding how breast cancer (BC) grows in axillary lymph nodes (ALNs), and refining how therapies might halt that process, is clinically important. However, modelling the complex ALN microenvironment is difficult, and no human models exist at present. We harvested ALNs from ten BC patients, and perfused them at 37 °C ex vivo for up to 24 h. Controlled autologous testing showed that ALNs remain viable after 24 h of ex vivo perfusion: haematoxylin and eosin-stained histological appearance and proliferation (by Ki67 immunohistochemistry) did not change significantly over time for any perfused ALN compared with a control from time-point zero. Furthermore, targeted gene expression analysis (NanoString PanCancer IO360 panel) showed that only 21/750 genes were differentially expressed between control and perfused ALNs (|log2 FC| > 1 and q < 0.1): none were involved in apoptosis and metabolism, but rather all 21 genes were involved in immune function and angiogenesis. During perfusion, tissue acid-base balance remained stable. Interestingly, the flow rate increased (p < 0.001) in cancer-replaced (i.e. metastasis occupied more than 90% of the surface area on multiple levels) compared to cancer-free nodes (i.e. nodes with no metastasis on multiple sections). CXCL11 transcripts were significantly more abundant in cancer-replaced nodes, while CXCL12 transcripts were significantly more abundant in cancer-free nodes. These cytokines were also detected in the circulating perfusate. Monoclonal antibodies (nivolumab and trastuzumab) were administered into a further three ALNs to confirm perfusion efficacy. These drugs saturated the nodes; nivolumab even induced cancer cell death. Normothermic ALN perfusion is not only feasible but sustains the tumour microenvironment ex vivo for scientific investigation. This model could facilitate the identification of actionable immuno-oncology targets. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

The contributions of viral hepatitis and alcohol to liver-related deaths in opioid-dependent people.

BACKGROUND: Mortality rates are elevated among heroin-dependent populations compared to the general population. Liver disease is emerging as an important contributor to mortality as the heroin-dependent population ages. Two major risk factors for liver disease are hepatitis C virus infection and chronic heavy alcohol use. Both of these are highly prevalent among heroin dependent people, but their relative contribution to liver-related mortality is poorly understood. METHODS: Data recording all prescriptions of opioid substitution treatment in New South Wales, Australia, 1997-2005, were linked to the National Death Index. Crude and standardised mortality rates and standardised mortality ratios were calculated for liver-related and other major causes of death. Frequency counts were obtained for viral hepatitis and alcohol mentions in underlying liver deaths. RESULTS: There were 208 underlying liver deaths for a CMR of 72.4 per 100,000 py (95% CI 62.9, 82.9), and liver deaths occurred at 9.8 times the general population rate (95% CI 8.5, 11.2). There were increases in liver-related mortality over time. Viral hepatitis was mentioned in three-quarters (n=156, 76%), and alcohol in 43% (n=90) of underlying liver deaths. CONCLUSIONS: Liver-related deaths were shown to be increasing in this heroin-dependent population, and the majority of these deaths involved chronic viral hepatitis infection. Increased uptake of treatment for hepatitis C virus infection is crucial to reducing the burden of liver-related mortality in this population. Hepatitis B vaccination, and screening of OST patients for alcohol use disorders and delivery of brief interventions as clinically indicated may also be of benefit.

The increasing mortality burden of liver disease among opioid-dependent people: cohort study.

AIMS: Hepatitis C (HCV) infection is highly prevalent among injection drug users (IDUs) and likely to cause significant mortality over time, but little research attention has focused upon the magnitude of this risk, particularly among ageing users. This study examined trends over time in mortality attributed to liver disease, and in particular contrasting this with other more commonly studied causes of death [acquired immune deficiency syndrome (AIDS), suicide and overdose] among an ageing cohort of heroin-dependent people in Australia. DESIGN: Data linkage study of methadone treatment entrants with the National Deaths Index. SETTING: A cohort entering methadone treatment for heroin dependence in New South Wales, Australia, 1980-85. PARTICIPANTS: A total of 2489 people entering methadone treatment for heroin dependence and 54,847 person-years (PY) of follow-up. MEASUREMENTS: Linkage of data on all methadone entrants between 1980 and 1985 with data from the Australian National Deaths Index, linked using probabilistic record linkage software. FINDINGS: There were 8.2 deaths per 1000 PY [95% confidence interval (CI) 7.5-9.0], with standardized mortality ratios (SMRs) of 4.6 (95% CI 4.2-5.0). Almost one in five (17%) of deaths were from underlying liver-related causes, most commonly viral hepatitis. The overall mortality rate for any liver cause was 1.4 deaths per 1000 PY (95% CI 1.1-1.7), 17 times higher than to the general population (95% CI 13.4-21.3), with relative elevations more marked for females (SMR 27.9; 95% CI 17.7-41.9) than males (SMR 14.5; 95% CI 10.8-19.0). Liver mortality increased over time, becoming the most common cause of death by the end of follow-up. CONCLUSIONS: Liver disease has become the most common cause of mortality among ageing opioid-dependent people in an ageing Australian cohort. There is an imperative to reduce the long-term risks of HCV and other risks to the liver, including alcohol consumption, which are typically not the major clinical focus for this group.

Follow-up difficulty: correlates and relationship with outcome in heroin dependence treatment in the NEPOD study.

Data collected from 317 heroin users who participated in four studies that were included in the Australian National Evaluation of Pharmacotherapies for Opioid Dependence were analysed to examine predictors of follow-up difficulty and whether follow-up difficulty was related to heroin use outcomes. Participants who were no longer receiving treatment were more difficult to contact and more likely to be lost to follow-up. Participants treated in general practice settings were also more difficult to contact and more likely to be lost to follow-up than participants treated at specialist clinics. Contact difficulty among followed-up participants (either in or out of treatment) was unrelated to heroin use outcomes. The 21% of participants who were followed-up with just one contact attempt reported 20.0 heroin-free days in the previous month, increasing only slightly to 20.9 based on the 70% of participants eventually contacted after up to 20 attempts. The study examined three methods for imputing missing heroin use outcome data and concluded that imputation of missing outcome data by inserting corresponding baseline data may be too conservative.

The impact of illicit drug market changes on health agency operations in Sydney, Australia.

At the end of 2000, in Sydney, Australia, there was a dramatic reduction in heroin availability. This study examines how health agencies treating clients for drug and alcohol related issues were able to respond to the changes that took place in their clients and their treatment needs. Key informant interviews were conducted with 48 staff from a wide range of health services in Sydney to provide the data for a thematic analysis. Changes experienced by health agencies included changed patterns of drug use in their clients, increased aggressive incidents, changed numbers of clients accessing treatment services, and a need for more assistance from outside agencies. A strong evidence base for a range of drug treatment options, support of staff development in aggression management skills, and development of good interagency links between mental health, drug and alcohol, and law enforcement services would make health services better prepared for future changes in the drug use of their clients.

A comparison of buprenorphine treatment in clinic and primary care settings: a randomised trial.

OBJECTIVE: To compare outcomes, costs and incremental cost-effectiveness of heroin detoxification performed in a specialist clinic and in general practice. DESIGN AND SETTING: Randomised controlled trial set in a specialist outpatient drug treatment centre and six office-based general practices in inner city Sydney, Australia. PARTICIPANTS: 115 people seeking treatment for heroin dependence, of whom 97 (84%) were reinterviewed at Day 8, and 78 (68%) at Day 91. INTERVENTIONS: Participants were randomly allocated to primary care or a specialist clinic, and received buprenorphine for 5 days for detoxification, then were offered either maintenance therapy with methadone or buprenorphine, relapse prevention with naltrexone, or counselling alone. MAIN OUTCOME MEASURES: Completion of detoxification, engagement in post-detoxification treatment, and heroin use assessed at Days 8 and 91. Costs relevant to providing treatment, including staff time, medication use and diagnostic procedures, with abstinence from heroin use on Day 8 as the primary outcome measure. RESULTS: There were no significant differences in the proportions completing detoxification (40/56 [71%] primary care v 46/59 [78%] clinic), participating in postwithdrawal treatment (28/56 [50%] primary care v 36/59 [61%] clinic), reporting no opiate use during the withdrawal period (13/56 [23%] primary care v 13/59 [22%] clinic), and in duration of postwithdrawal treatment by survival analysis. Most participants in both groups entered postwithdrawal buprenorphine maintenance. On an intention-to-treat basis, self-reported heroin use in the month before the Day 91 interview was significantly lower than at baseline (27 days/month at baseline, 14 days/month at Day 91; P < 0.001) and did not differ between groups. Buprenorphine detoxification in primary care was estimated to be $24 more expensive per patient than treatment at the clinic. The incremental cost-effectiveness ratio reveals that, in this context, it costs $20 to achieve a 1% improvement in outcome in primary care. CONCLUSIONS: Buprenorphine-assisted detoxification from heroin in specialist clinic and primary care settings had similar efficacy and cost-effectiveness. Buprenorphine treatment can be initiated safely in primary care settings by trained GPs.