CTCF prevents genomic instability by promoting homologous recombination-directed DNA double-strand break repair.

CTCF is an essential epigenetic regulator mediating chromatin insulation, long-range regulatory interactions, and the organization of large topological domains in the nucleus. Phenotypes of CTCF haploinsufficient mutations in humans, knockout in mice, and depletion in cells are often consistent with impaired genome stability, but a role of CTCF in genome maintenance has not been fully investigated. Here, we report that CTCF maintains genome stability, is recruited to sites of DNA damage, and promotes homologous recombination repair of DNA double-strand breaks (DSBs). CTCF depletion increased chromosomal instability, marked by chromosome breakage and end fusions, elevated genotoxic stress-induced genomic DNA fragmentation, and activated the ataxia telangiectasia mutated (ATM) kinase. We show that CTCF could be recruited to drug-induced 53BP1 foci and known fragile sites, as well as to I-SceI endonuclease-induced DSBs. Laser irradiation analysis revealed that this recruitment depends on ATM, Nijmegen breakage syndrome (NBS), and the zinc finger DNA-binding domain of CTCF. We demonstrate that CTCF knockdown impaired homologous recombination (HR) repair of DSBs. Consistent with this, CTCF knockdown reduced the formation of γ-radiation-induced Rad51 foci, as well as the recruitment of Rad51 to laser-irradiated sites of DNA lesions and to I-SceI-induced DSBs. We further show that CTCF is associated with DNA HR repair factors MDC1 and AGO2, and directly interacts with Rad51 via its C terminus. These analyses establish a direct, functional role of CTCF in DNA repair and provide a potential link between genome organization and genome stability.

The demographic profile of young patients (<45 years-old) with acute coronary syndromes in Queensland.

BACKGROUND: There is little data regarding the demographic profile of young (<45 years) Australian acute coronary syndrome patients. The aim of this study was to compare baseline characteristics, risk factor profile and outcomes of young patients compared with their older counterparts referred to two metropolitan Queensland hospitals. METHODS: Over a four-year period, data on acute coronary syndrome patients referred to The Prince Charles and Royal Brisbane Hospitals were retrospectively analysed. Three major groups were identified: <45 years, 45-60 years and those >60 years. Age, sex, body mass index, risk factor profile, degree of coronary disease, left ventricular dysfunction, mode of presentation, initial pharmacological therapy and mortality data were compared between the three groups. RESULTS: 4549 patients were analysed of whom, 277 were less than 45 years old. Younger patients tended to be male, more overweight and present more commonly with ST segment elevation myocardial infarction compared to their older counterparts. Smoking, family history and dyslipidaemia tended to occur more frequently in younger patients as compared to those >45 years. Those patients >45 years tended to present with non-ST segment elevation myocardial infarction and have a higher degree of ischaemic burden and left ventricular dysfunction. No patients <45 years died in their index admission at 30 days or at one year. CONCLUSIONS: Although young patients <45 years make up the minority (6.1%) of patients presenting with acute coronary syndrome and generally have a favourable prognosis, this paper highlights the need for aggressive risk factor modification, with particular attention to smoking and dyslipidaemia, before the onset of overt clinical disease.

Cancer stem cell markers in prostate cancer: an immunohistochemical study of ALDH1, SOX2 and EZH2.

The aims of this study were to investigate the immunohistochemical expression and potential prognostic significance of putative cancer stems cell markers ALDH1, EZH2 and SOX2 in prostate cancer.A total of 142 consecutive radical prostatectomies submitted to one laboratory with a diagnosis of prostatic adenocarcinoma between 2008 and 2012 were retrieved and retrospectively studied. Immunohistochemistry for the three markers was performed in each case and both univariate and multivariate analyses were undertaken to evaluate the correlation between the staining patterns and known histopathological prognostic features.ALDH1 showed a statistically significant association with tumour stage p < 0.001), extraprostatic extension (p < 0.001) and lymphovascular invasion (p = 0.001). EZH2 correlated with Gleason score (p = 0.044) and lymph node metastases (p = 0.023). SOX2 showed a statistically significant correlation with lymphovascular invasion only (p = 0.018) in both univariate and multivariate analyses.Cancer stem cell markers are variably expressed in prostate adenocarcinoma and immunohistochemical staining for ALDH1 and EZH2 may have a role in predicting tumour aggressiveness before treatment of prostate cancer.

Validation of a fentanyl transdermal adhesion scoring tool for use in clinical practice.

CONTEXT: The therapeutic efficacy of a transdermal system (TDS) is directly related to the adhesion of TDS, with partial adhesion resulting in lower plasma concentration. Currently there is no TDS adhesion scoring tool available for use in the clinical setting. OBJECTIVES: To validate a U.S. Food and Drug Administration (FDA) scoring system for the adhesion of the fentanyl TDS in cancer patients. METHODS: A library of images was created from photographs of fentanyl/placebo TDS placed on patients/volunteers. Thirty photographs, reflecting varying degrees of adhesion, were selected for each of series A and B, with 10 photographs common to both series. Each series was shown to 30 health professionals asked to score the photographs using the FDA scoring system. Validity was assessed using Spearman's rank correlation and reliability by Cohen's kappa (k). Photo editing software was used to assign control scores to each photograph. RESULTS: Validity was high for both series (≥ 0.954). Inter-reliability (k) ranged from 0.327 to 0.858 (average, 0.547) and 0.433-0.910 (average, 0.620) in series A and B, respectively. The combined agreement across both series was 0.585. Intra-rater agreement (k) of the 10 common images was 0.605. No significant difference was observed between the scoring patterns for those with more than 10 years of working experience. CONCLUSION: Overall, the TDS adhesion score determined by the participants visually in this study corresponded well to those generated by photo editing software, thus rendering the scoring system highly valid. The FDA scoring system is an adequate tool for assessing fentanyl TDS adhesion in clinical practice.

Relation of reduced preclinical left ventricular diastolic function and cardiac remodeling in overweight youth to insulin resistance and inflammation.

Insulin resistance (IR) and inflammation are associated with an increased risk of cardiovascular disease and may contribute to obesity cardiomyopathy. The earliest sign of obesity cardiomyopathy is impaired left ventricular (LV) diastolic function, which may be evident in obese children and adolescents. However, the precise metabolic basis of the impaired LV diastolic function remains unknown. The aims of this study were to evaluate cardiac structure and LV diastolic function by tissue Doppler imaging in overweight and obese (OW) youth and to assess the relative individual contributions of adiposity, IR, and inflammation to alterations in cardiac structure and function. We studied 35 OW (body mass index standard deviation score 2.0±0.8; non-IR n=19, IR n=16) and 34 non-OW youth (body mass index standard deviation score 0.1±0.7). LV diastolic function was reduced in OW youth compared with non-OW controls, as indicated by lower peak myocardial relaxation velocities (p<0.001) and greater filling pressures (p<0.001). OW youth also had greater LV mass index (p<0.001), left atrial volume index, and LV interventricular septal thickness (LV-IVS; both p=0.02). IR-OW youth had the highest LV filling pressures, LV-IVS, and relative wall thickness (all p<0.05). Homeostasis model of assessment-insulin resistance and C-reactive protein were negative determinants of peak myocardial relaxation velocity and positive predictors of filling pressure. Adiponectin was a negative determinant of LV-IVS, independent of obesity. In conclusion, OW youth with IR and inflammation are more likely to have adverse changes to cardiovascular structure and function which may predispose to premature cardiovascular disease in adulthood.