Identification of anti-hormone induced genes as potential therapeutic targets in breast cancer

Tamoxifen, a competitive inhibitor of oestradiol binding to the oestrogen receptor ER, remains a key anti-hormonal treatment for ER ve breast cancer although its effectiveness is limited by development of resistance. It is hypothesised that in addition to blockade of pro-proliferative/anti-apoptotic genes, anti-oestrogens exert an early protective effect, inducing cell survival and pro-invasive genes that enable a subset of cells to escape the anti-tumour effects of the anti-oestrogens and facilitate disease progression. It was hoped that identification of such early compensatory events in this thesis and their subsequent therapeutic targeting in combination with anti-oestrogens would be able to improve anti-tumour response. Proof of this principle exists since co-targeting of anti-oestrogen-induced epidermal growth factor receptor EGFR alongside tamoxifen has been reported to improve growth inhibition in ER ve MCF-7 human breast cancer cells and delay acquisition of resistance. After filtering, hierarchical clustering and ontological investigation, 8 possible compensatory genes were identified as anti-oestrogen tamoxifen and faslodex-induced /oestrogen-suppressed at an early time point in MCF-7 cells in vitro using cDNA microarrays bearing 1200 cancer-related genes, comparing anti-oestrogen with oestrogen E2 treatment and control oestrogen deprived conditions. RT-PCR and protein investigation gave further insight into expression levels of these genes based on ER occupancy. Genes induced by both an anti-oestrogen-occupied ER and an unoccupied ER versus E2 treatment were the Rnd family member RhoE and nucleoside diphosphate kinase NME3 implicated in migration and cell survival respectively, and the anti-apoptotic transcription factor NFkBl. The adhesive junction protein 5-catenin, cell survival elements 14-3-3 and chaperone Bag-1 and nuclear serine/threonine kinase NDR implicated in progression were all induced by an anti-oestrogen occupied ER but not by an unoccupied ER versus E2 treatment. Co-treating with the NFkB inhibitor parthenolide and faslodex suppressed NFkBl DNA binding, transcriptional activity and improved growth inhibition of MCF-7 cells. These data demonstrate that several genes of adverse potential are induced during the anti-oestrogen-responsive phase, and that their co-targeting has promise to improve anti-tumour response

Cardiovascular Responses to Orthostasis and Their Association With Falls in Older Adults

Background Orthostatic hypotension (OH) refers to a marked decline in blood pressure when upright. OH has a high incidence and prevalence in older adults and represents a potential intrinsic risk factor for falls in these individuals. Previous studies have not included more recent definitions for blood pressure responses to orthostasis, including initial, delayed, and recovery blood pressure responses. Furthermore, there is little research examining the relationships between cerebrovascular functioning and falling risk. Therefore, we aimed to: (i) test the association between different blood pressure responses to orthostatic stress and retrospective falling history and; (ii) test the association between cerebrovascular responses to orthostatic stress and falling history. Methods We tested 59 elderly residents in long term care facilities who underwent a passive seated orthostatic stress test. Beat-to-beat blood pressure and cerebral blood flow velocity (CBFV) responses were assessed throughout testing. Risk factors for falls and falling history were collected from facility records. Cardiovascular responses to orthostasis were compared between retrospective fallers (≥1 fall in the previous year) and non-fallers. Results Retrospective fallers had larger delayed declines in systolic arterial pressure (SAP) compared to non-fallers (p  = 0.015). Fallers also showed poorer early (2 min) and late (15 min) recovery of SAP. Fallers had a greater decline in systolic CBFV. Conclusions Older adults with a positive falling history have impaired orthostatic control of blood pressure and CBFV. With better identification and understanding of orthostatic blood pressure impairments earlier intervention and management can be implemented, potentially reducing the associated risk of morbidity and mortality. Future studies should utilize the updated OH definitions using beat-to-beat technology, rather than conventional methods that may offer less accurate detection

Survival of Dopaminergic Amacrine Cells after Near-Infrared Light Treatment in MPTP-Treated Mice

We examined whether near-infrared light (NIr) treatment (photobiomodulation) saves dopaminergic amacrine cells of the retina in an acute and a chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson disease. For the acute model, BALB/c mice had MPTP (100 mg/kg) or saline injections over 30 hours, followed by a six-day-survival period. For the chronic model, mice had MPTP (200 mg/kg) or saline injections over five weeks, followed by a three-week-survival period. NIr treatment was applied either at the same time (simultaneous series) or well after (posttreatment series) the MPTP insult. There were four groups within each series: Saline, Saline-NIr, MPTP, and MPTP-NIr. Retinae were processed for tyrosine hydroxylase (TH) immunochemistry, and cell number was analysed. In the MPTP groups, there was a significant reduction in TH+ cell number compared to the saline controls; this reduction was greater in the acute (~50%) compared to the chronic (~30%) cases. In the MPTP-NIr groups, there were significantly more TH+ cells than in the MPTP groups of both series (~30%). In summary, we showed that NIr treatment was able to both protect (simultaneous series) and rescue (posttreatment series) TH+ cells of the retina from parkinsonian insult

Serum response factor cleavage by caspases 3 and 7 linked to apoptosis in human BJAB cells

Apoptosis involves the cessation of cellular processes, the breakdown of intracellular organelles, and, finally, the nonphlogistic clearance of apoptotic cells from the body. Important for these events is a family of proteases, caspases, which are activated by a proteolytic cleavage cascade and drive apoptosis by targeting key proteins within the cell. Here, we demonstrate that serum response factor (SRF), a transcription factor essential for proliferative gene expression, is cleaved by caspases and that this cleavage occurs in proliferating murine fibroblasts and can be induced in the human B-cell line BJAB. We identify the two major sites at which SRF cleavage occurs as Asp245 and Asp254, the caspases responsible for the cleavage and generate a mutant of SRF resistant to cleavage in BJAB cells. Investigation of the physiological and functional significance of SRF cleavage reveals that it correlates with the loss of e-fos expression, whereby neither SRF cleavage fragment retains transcriptional activity. Moreover, the expression of a noncleavable SRF in BJAB cells suppresses apoptosis induced by Fas cross-linking. These results suggest that for apoptosis to proceed, the transcriptional events promoting cell survival and proliferation, in which SRF is involved, must first be inactivated

Relationships between Orthostatic Hypotension, Frailty, Falling and Mortality in Elderly Care Home Residents

Background: Orthostatic hypotension (OH; profound falls in blood pressure when upright) is a common deficit that increases in incidence with age, and may be associated with falling risk. Deficit accumulation results in frailty, regarded as enhanced vulnerability to adverse outcomes. We aimed to evaluate the relationships between OH, frailty, falling and mortality in elderly care home residents. Methods: From the Minimum Data Set (MDS) document, a frailty index (FI-MDS) was generated from a list of 58 deficits, ranging from 0 (no deficits) to 1.0 (58 deficits). OH was evaluated from beat-to-beat blood pressure and heart rate (finger plethysmography) collected during a 15-min supine-seated orthostatic stress test. Retrospective and prospective falling rates (falls/year) were extracted from facility falls incident reports. All-cause 3-year mortality was determined. Data are reported as mean ± standard error. Results: Data were obtained from 116 older adults (aged 84.2 ± 0.9 years; 44% males) living in two long term care facilities. The mean FI-MDS was 0.36 ± 0.01; FI-MDS was correlated with age (r = 0.277; p = 0.003). Those who were frail (FI ≥ 0.27) had larger Initial (− 17.8 ± 4.2 vs − 6.1 ± 3.3 mmHg, p = 0.03) and Consensus (− 22.7 ± 4.3 vs − 11.5 ± 3. 3 mmHg, p = 0.04) orthostatic reductions in systolic arterial pressure. Frail individuals had higher prospective and retrospective falling rates and higher 3-year mortality. Receiver operating characteristic curves evaluated the ability of FI-MDS alone to predict prospective falls (sensitivity 72%, specificity 36%), Consensus OH (sensitivity 68%, specificity 60%) and 3-year mortality (sensitivity 77%, specificity 49%). Kaplan Meier survival analyses showed significantly higher 3-year mortality in those who were frail compared to the non-frail (p = 0.005). Conclusions: Frailty can be captured using a frailty index based on MDS data in elderly individuals living in long term care, and is related to susceptibility to orthostatic hypotension, falling risk and 3-year mortality. Use of the MDS to generate a frailty index may represent a simple and convenient risk assessment tool for older adults living in long term care. Older adults who are both frail and have impaired orthostatic blood pressure control have a particularly high risk of falling and should receive tailored management to mitigate this ris

LoCuSS: A Comparison of Sunyaev-Zel'dovich Effect and Gravitational Lensing Measurements of Galaxy Clusters

We present the first measurement of the relationship between the Sunyaev-Zel'dovich effect signal and the mass of galaxy clusters that uses gravitational lensing to measure cluster mass, based on 14 X-ray luminous clusters at z~0.2 from the Local Cluster Substructure Survey. We measure the integrated Compton y-parameter, Y, and total projected mass of the clusters (M_GL) within a projected clustercentric radius of 350 kpc, corresponding to mean overdensities of 4000-8000 relative to the critical density. We find self-similar scaling between M_GL and Y, with a scatter in mass at fixed Y of 32%. This scatter exceeds that predicted from numerical cluster simulations, however, it is smaller than comparable measurements of the scatter in mass at fixed T_X. We also find no evidence of segregation in Y between disturbed and undisturbed clusters, as had been seen with T_X on the same physical scales. We compare our scaling relation to the Bonamente et al. relation based on mass measurements that assume hydrostatic equilibrium, finding no evidence for a hydrostatic mass bias in cluster cores (M_GL = 0.98+/-0.13 M_HSE), consistent with both predictions from numerical simulations and lensing/X-ray-based measurements of mass-observable scaling relations at larger radii. Overall our results suggest that the Sunyaev-Zel'dovich effect may be less sensitive than X-ray observations to the details of cluster physics in cluster cores.Comment: Minor changes to match published version: 2009 ApJL 701:114-11

Salt intake and dietary sources of salt on weekdays and weekend days in Australian adults

ObjectiveTo assess if there is a difference in salt intake (24 h urine collection and dietary recall) and dietary sources of salt (Na) on weekdays and weekend days.DesignA cross-sectional study of adults who provided one 24 h urine collection and one telephone-administered 24 h dietary recall.SettingCommunity-dwelling adults living in the State of Victoria, Australia.SubjectsAdults (n 598) who participated in a health survey (53&middot;5 % women; mean age 57&middot;1 (95 % CI 56&middot;2, 58&middot;1) years).ResultsMean (95 % CI) salt intake (dietary recall) was 6&middot;8 (6&middot;6, 7&middot;1) g/d and 24 h urinary salt excretion was 8&middot;1 (7&middot;8, 8&middot;3) g/d. Mean dietary and 24 h urinary salt (age-adjusted) were 0&middot;9 (0&middot;1, 1&middot;6) g/d (P=0&middot;024) and 0&middot;8 (0&middot;3, 1&middot;6) g/d (P=0&middot;0017), respectively, higher at weekends compared with weekdays. There was an indication of a greater energy intake at weekends (+0&middot;6 (0&middot;02, 1&middot;2) MJ/d, P=0&middot;06), but no difference in Na density (weekday: 291 (279, 304) mg/MJ; weekend: 304 (281, 327) mg/MJ; P=0&middot;360). Cereals/cereal products and dishes, meat, poultry, milk products and gravy/sauces accounted for 71 % of dietary Na.ConclusionsMean salt intake (24 h urine collection) was more than 60 % above the recommended level of 5 g salt/d and 8&ndash;14 % more salt was consumed at weekends than on weekdays. Substantial reductions in the Na content of staple foods, processed meat, sauces, mixed dishes (e.g. pasta), convenience and takeaway foods are required to achieve a significant consistent reduction in population salt intake throughout the week.<br /

Exploring causality in the association between circulating 25-hydroxyvitamin D and colorectal cancer risk:a large Mendelian randomisation study

Background: Whilst observational studies establish that lower plasma 25-hydroxyvitamin D (25-OHD) levels are associated with higher risk of colorectal cancer (CRC), establishing causality has proven challenging. Since vitamin D is modifiable, these observations have substantial clinical and public health implications. Indeed, many health agencies already recommend supplemental vitamin D. Here, we explore causality in a large Mendelian randomisation (MR) study using an improved genetic instrument for circulating 25-OHD. Methods: We developed a weighted genetic score for circulating 25-OHD using six genetic variants that we recently reported to be associated with circulating 25-OHD in a large genome-wide association study (GWAS) meta-analysis. Using this score as instrumental variable in MR analyses, we sought to determine whether circulating 25-OHD is causally linked with CRC risk We conducted MR analysis using individual-level data from 10,725 CRC cases and 30,794 controls (Scotland, UK Biobank and Croatia). We then applied estimates from meta-analysis of 11 GWAS of CRC risk (18,967 cases; 48,168 controls) in a summary statistics MR approach. Results: The new genetic score for 25-OHD was strongly associated with measured plasma 25-OHD levels in 2821 healthy Scottish controls (P = 1.47 x 10(-11)), improving upon previous genetic instruments (F-statistic 46.0 vs. 13.0). However, individual-level MR revealed no association between 25-OHD score and CRC risk (OR 1.03/unit log-transformed circulating 25-OHD, 95% CI 0.51-2.07, P= 0.93). Similarly, we found no evidence for a causal relationship between 25-OHD and CRC risk using summary statistics MR analysis (OR 0.91, 95% CI 0.69-1.19, P= 0.48). Conclusions: Despite the scale of this study and employing an improved score capturing more of the genetic contribution to circulating 25-OHD, we found no evidence for a causal relationship between circulating 25-OHD and CRC risk Although the magnitude of effect for vitamin D suggested by observational studies can confidently be excluded, smaller effects sizes and non-linear relationships remain plausible. Circulating vitamin D may be a CRC biomarker, but a causal effect on CRC risk remains unproven

Telomere length analysis in amyotrophic lateral sclerosis using large-scale whole genome sequence data

BackgroundAmyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the loss of upper and lower motor neurons, leading to progressive weakness of voluntary muscles, with death following from neuromuscular respiratory failure, typically within 3 to 5 years. There is a strong genetic contribution to ALS risk. In 10% or more, a family history of ALS or frontotemporal dementia is obtained, and the Mendelian genes responsible for ALS in such families have now been identified in about 50% of cases. Only about 14% of apparently sporadic ALS is explained by known genetic variation, suggesting that other forms of genetic variation are important. Telomeres maintain DNA integrity during cellular replication, differ between sexes, and shorten naturally with age. Sex and age are risk factors for ALS and we therefore investigated telomere length in ALS. MethodsSamples were from Project MinE, an international ALS whole genome sequencing consortium that includes phenotype data. For validation we used donated brain samples from motor cortex from people with ALS and controls. Ancestry and relatedness were evaluated by principal components analysis and relationship matrices of DNA microarray data. Whole genome sequence data were from Illumina HiSeq platforms and aligned using the Isaac pipeline. TelSeq was used to quantify telomere length using whole genome sequence data. We tested the association of telomere length with ALS and ALS survival using Cox regression. ResultsThere were 6,580 whole genome sequences, reducing to 6,195 samples (4,315 from people with ALS and 1,880 controls) after quality control, and 159 brain samples (106 ALS, 53 controls). Accounting for age and sex, there was a 20% (95% CI 14%, 25%) increase of telomere length in people with ALS compared to controls (p = 1.1 x 10(-12)), validated in the brain samples (p = 0.03). Those with shorter telomeres had a 10% increase in median survival (p = 5.0x10(-7)). Although there was no difference in telomere length between sporadic ALS and familial ALS (p=0.64), telomere length in 334 people with ALS due to expanded C9orf72 repeats was shorter than in those without expanded C9orf72 repeats (p = 5.0x10(-4)). DiscussionAlthough telomeres shorten with age, longer telomeres are a risk factor for ALS and worsen prognosis. Longer telomeres are associated with ALS