Roscovitine Modulates DNA Repair and Senescence: Implications for Combination Chemotherapy

PURPOSE: Treatment of tumor cells by chemotherapy activates a series of responses ranging from apoptosis to premature senescence and repair. Survival responses are characterized by inhibition of cyclin-dependent kinases. Because inhibition of cyclin-dependent kinases represents a distinctive feature of DNA damage-induced prosurvival responses, we investigated the possibility that the cyclin-dependent kinase inhibitor roscovitine modulates drug-induced responses in human adenocarcinoma cells, favoring cell survival. EXPERIMENTAL DESIGN: Sublethal concentrations of doxorubicin were used to induce premature senescence in human adenocarcinoma cells. The effect of the cyclin-dependent kinase inhibitor roscovitine on the doxorubicin-dependent cell cycle checkpoint activation and DNA repair pathways was evaluated. RESULTS: Roscovitine reinforces doxorubicin-dependent G(1) checkpoint in A549 and HEC1B cells leading to decreased frequency of double-strand breaks and to the preferential induction of senescence and enhanced clonogenic survival. However, in other tumor cell lines, such as HCT116 and H1299, combined treatment with doxorubicin and roscovitine increases the frequency of double-strand breaks and dramatically sensitizes to doxorubicin. This unexpected effect of roscovitine depends on a novel ability to inhibit DNA double-strand break repair processes and requires inactivation of the pRb pathway. CONCLUSIONS: Roscovitine, by hindering DNA repair processes, has the potential to inhibit recovery of mildly damaged tumor cells after doxorubicin treatment and to increase the susceptibility of tumor cells to chemotherapy. However, in some tumor cells, the cell cycle inhibitory function of roscovitine prevails over the DNA repair inhibitory activity, favoring premature senescence and clonogenic growth. These data indicate a novel mechanism underlying combined chemotherapy, which may have wide application in treatment of carcinomas

A qualitative exploration of the effect of visual field loss on daily life in home-dwelling stroke survivors

Objective: To explore the effect of visual field loss on the daily life of community-dwelling stroke survivors. Design: A qualitative interview study. Participants: Adult stroke survivors with visual field loss of at least six months’ duration. Methods: Semi-structured interviews were conducted with a non-purposive sample of 12 stroke survivors in their own homes. These were recorded, transcribed verbatim and analyzed with the framework method, using an inductive approach. Results: Two key analytical themes emerged. ‘Perception, experience and knowledge’ describes participant’s conflicted experience of having knowledge of their impaired vision but lacking perception of that visual field loss and operating under the assumption that they were viewing an intact visual scene when engaged in activities. Inability to recognize and deal with visual difficulties, and experiencing the consequences, contributed to their fear and loss of self-confidence. ‘Avoidance and adaptation’ were two typologies of participant response to visual field loss. Initially, all participants consciously avoided activities. Some later adapted to vision loss using self-directed head and eye scanning techniques. Conclusions: Visual field loss has a marked impact on stroke survivors. Stroke survivors lack perception of their visual loss in everyday life, resulting in fear and loss of confidence. Activity avoidance is a common response, but in some, it is replaced by self-initiated adaptive techniques

Home-based exercise for people living with frailty and chronic kidney disease: A mixedmethods pilot randomised controlled trial

Background Frailty is associated with adverse health outcomes in people with chronic kidney disease (CKD). Evidence supporting targeted interventions is needed. This pilot randomised controlled trial (RCT) aimed to inform the design of a definitive RCT evaluating the effectiveness of a home-based exercise intervention for pre-frail and frail older adults with CKD. Methods Participants were recruited from nephrology outpatient clinics to this two-arm parallel group mixed-methods pilot RCT. Inclusion criteria were: ≥65 years old; CKD G3b-5; and Clinical Frailty Scale score ≥4. Participants categorised as pre-frail or frail using the Frailty Phenotype were randomised to a 12-week progressive multi-component home-based exercise programme or usual care. Primary outcome measures included eligibility, recruitment, adherence, outcome measure completion and participant attrition rate. Semi-structured interviews were conducted with participants to explore trial and intervention acceptability. Results Six hundred and sixty-five patients had an eligibility assessment with 217 (33%; 95% CI 29, 36) eligible. Thirty-five (16%; 95% CI 12, 22) participants were recruited. Six were categorised as robust and withdrawn prior to randomisation. Fifteen participants were randomised to exercise and 14 to usual care. Eleven (73%; 95% CI 45, 91) participants completed ≥2 exercise sessions/week. Retained participants completed all outcome measures (n = 21; 100%; 95% CI 81, 100). Eight (28%; 95% CI 13, 47) participants were withdrawn. Fifteen participated in interviews. Decision to participate/withdraw was influenced by perceived risk of exercise worsening symptoms. Participant perceived benefits included improved fitness, balance, strength, well-being, energy levels and confidence. Conclusions This pilot RCT demonstrates that progression to definitive RCT is possible provided recruitment and retention challenges are addressed. It has also provided preliminary evidence that home-based exercise may be beneficial for people living with frailty and CKD

The EX-FRAIL CKD trial: A study protocol for a pilot randomised controlled trial of a home-based EXercise programme for pre-frail and FRAIL, older adults with Chronic Kidney Disease

Introduction Frailty is highly prevalent in adults with chronic kidney disease (CKD) and is associated with adverse health outcomes including falls, poorer health-related quality of life (HRQOL), hospitalisation and mortality. Low physical activity and muscle wasting are important contributors to physical frailty in adults with CKD. Exercise training may improve physical function and frailty status leading to associated improvements in health outcomes, including HRQOL. The EX-FRAIL CKD trial aims to inform the design of a definitive randomised controlled trial (RCT) that investigates the effectiveness of a progressive, multicomponent home-based exercise programme in prefrail and frail older adults with CKD. Methods and analysis The EX-FRAIL CKD trial is a two-arm parallel group pilot RCT. Participants categorised as prefrail or frail, following Frailty Phenotype (FP) assessment, will be randomised to receive exercise or usual care. Participants randomised to the intervention arm will receive a tailored 12-week exercise programme, which includes weekly telephone calls to advise on exercise progression. Primary feasibility outcome measures include rate of recruitment, intervention adherence, outcome measure completion and participant attrition. Semistructured interviews with a purposively selected group of participants will inform the feasibility of the randomisation procedures, outcome measures and intervention. Secondary outcome measures include physical function (walking speed and Short Physical Performance Battery), frailty status (FP), fall concern (Falls Efficacy Scale-International tool), activities of daily living (Barthel Index), symptom burden (Palliative care Outcome Scale-Symptoms RENAL) and HRQOL (Short Form-12v2). Ethics and dissemination Ethical approval was granted by a National Health Service (NHS) Regional Ethics Committee and the NHS Health Research Authority. The study team aims to publish findings in a peer-reviewed journal and presents the results at relevant national and international conferences. A summary of findings will be provided to participants, a local kidney patient charity and the funding body. Trial registration number ISRCTN87708989

ZNF804a Regulates Expression of the Schizophrenia-Associated Genes PRSS16, COMT, PDE4B, and DRD2

ZNF804a was identified by a genome-wide association study (GWAS) in which a single nucleotide polymorphism (SNP rs1344706) in ZNF804a reached genome-wide statistical significance for association with a combined diagnosis of schizophrenia (SZ) and bipolar disorder. Although the molecular function of ZNF804a is unknown, the amino acid sequence is predicted to contain a C2H2-type zinc-finger domain and suggests ZNF804a plays a role in DNA binding and transcription. Here, we confirm that ZNF804a directly contributes to transcriptional control by regulating the expression of several SZ associated genes and directly interacts with chromatin proximal to the promoter regions of PRSS16 and COMT, the two genes we find upregulated by ZNF804a. Using immunochemistry we establish that ZNF804a is localized to the nucleus of rat neural progenitor cells in culture and in vivo. We demonstrate that expression of ZNF804a results in a significant increase in transcript levels of PRSS16 and COMT, relative to GFP transfected controls, and a statistically significant decrease in transcript levels of PDE4B and DRD2. Furthermore, we show using chromatin immunoprecipitation assays (ChIP) that both epitope-tagged and endogenous ZNF804a directly interacts with the promoter regions of PRSS16 and COMT, suggesting a direct upregulation of transcription by ZNF804a on the expression of these genes. These results are the first to confirm that ZNF804a regulates transcription levels of four SZ associated genes, and binds to chromatin proximal to promoters of two SZ genes. These results suggest a model where ZNF804a may modulate a transcriptional network of SZ associated genes