Mitotic clustering of pulverized chromosomes from micronuclei.

Complex genome rearrangements can be generated by the catastrophic pulverization of missegregated chromosomes trapped within micronuclei through a process known as chromothripsis1-5. As each chromosome contains a single centromere, it remains unclear how acentric fragments derived from shattered chromosomes are inherited between daughter cells during mitosis6. Here we tracked micronucleated chromosomes with live-cell imaging and show that acentric fragments cluster in close spatial proximity throughout mitosis for asymmetric inheritance by a single daughter cell. Mechanistically, the CIP2A-TOPBP1 complex prematurely associates with DNA lesions within ruptured micronuclei during interphase, which poises pulverized chromosomes for clustering upon mitotic entry. Inactivation of CIP2A-TOPBP1 caused acentric fragments to disperse throughout the mitotic cytoplasm, stochastically partition into the nucleus of both daughter cells and aberrantly misaccumulate as cytoplasmic DNA. Mitotic clustering facilitates the reassembly of acentric fragments into rearranged chromosomes lacking the extensive DNA copy-number losses that are characteristic of canonical chromothripsis. Comprehensive analysis of pan-cancer genomes revealed clusters of DNA copy-number-neutral rearrangements-termed balanced chromothripsis-across diverse tumour types resulting in the acquisition of known cancer driver events. Thus, distinct patterns of chromothripsis can be explained by the spatial clustering of pulverized chromosomes from micronuclei.

Author Correction: CPS1 maintains pyrimidine pools and DNA synthesis in KRAS/LKB1-mutant lung cancer cells.

Further analysis has revealed that the signal reported in Extended Data Fig. 1c of this Letter is attributed to phosphorylethanolamine, not carbamoyl phosphate. A newly developed derivatization method revealed that the level of carbamoyl phosphate in these NSCLC extracts is below the detection threshold of approximately 10 nanomoles. These findings do not alter the overall conclusions of the Letter; see associated Amendment for full details. The Letter has not been corrected online.

DFT study on the catalytic decomposition of hydrogen peroxide by iron complexes of nitrilotriacetate.

The Fenton system in the presence of nitrilotriacetate (NTA) ligand is studied by DFT approach. The calculations show that complexation of Fe(II) with NTA significantly facilitates the H2 O2 activation. The ferric-hydroperoxo intermediate NTAFe(III)OOH predominantly decays via the disproportionation into NTAFe(II)OH2 and NTAFe(IV)O involving the formation of a µ-1,2-hydroperoxo-bridged biferric intermediate. In this mechanism, the bridged hydroperoxo is reduced by hydroperoxo ligand rather than by Fe(III). On the one hand, the NTAFe(III)OOH is sluggish to undergo hydrogen abstraction; on the other hand, it is a good nucleophile that may perform aldehyde deformylation. The present calculations suggest that both ˙OH and Fe(IV)O are generated in the NTA-assisted Fenton system. However, the polycarboxylate ligand provides a favorable environment for H2 O2 to accumulate around iron ion through hydrogen bonding. This promotes the quenching of Fe(IV)O by H2 O2 , rationalizing why the Fe(IV)O species is hardly detected in the NTA-assisted Fenton system.

CPS1 maintains pyrimidine pools and DNA synthesis in KRAS/LKB1-mutant lung cancer cells.

Metabolic reprogramming by oncogenic signals promotes cancer initiation and progression. The oncogene KRAS and tumour suppressor STK11, which encodes the kinase LKB1, regulate metabolism and are frequently mutated in non-small-cell lung cancer (NSCLC). Concurrent occurrence of oncogenic KRAS and loss of LKB1 (KL) in cells specifies aggressive oncological behaviour. Here we show that human KL cells and tumours share metabolomic signatures of perturbed nitrogen handling. KL cells express the urea cycle enzyme carbamoyl phosphate synthetase-1 (CPS1), which produces carbamoyl phosphate in the mitochondria from ammonia and bicarbonate, initiating nitrogen disposal. Transcription of CPS1 is suppressed by LKB1 through AMPK, and CPS1 expression correlates inversely with LKB1 in human NSCLC. Silencing CPS1 in KL cells induces cell death and reduces tumour growth. Notably, cell death results from pyrimidine depletion rather than ammonia toxicity, as CPS1 enables an unconventional pathway of nitrogen flow from ammonia into pyrimidines. CPS1 loss reduces the pyrimidine to purine ratio, compromises S-phase progression and induces DNA-polymerase stalling and DNA damage. Exogenous pyrimidines reverse DNA damage and rescue growth. The data indicate that the KL oncological genotype imposes a metabolic vulnerability related to a dependence on a cross-compartmental pathway of pyrimidine metabolism in an aggressive subset of NSCLC.

Elevated Hippocampal CRMP5 Mediates Chronic Stress-Induced Cognitive Deficits by Disrupting Synaptic Plasticity, Hindering AMPAR Trafficking, and Triggering Cytokine Release.

Chronic stress is a critical risk factor for developing depression, which can impair cognitive function. However, the underlying mechanisms involved in chronic stress-induced cognitive deficits remain unclear. Emerging evidence suggests that collapsin response mediator proteins (CRMPs) are implicated in the pathogenesis of psychiatric-related disorders. Thus, the study aims to examine whether CRMPs modulate chronic stress-induced cognitive impairment. We used the chronic unpredictable stress (CUS) paradigm to mimic stressful life situations in C57BL/6 mice. In this study, we found that CUS-treated mice exhibited cognitive decline and increased hippocampal CRMP2 and CRMP5 expression. In contrast to CRMP2, CRMP5 levels strongly correlated with the severity of cognitive impairment. Decreasing hippocampal CRMP5 levels through shRNA injection rescued CUS-induced cognitive impairment, whereas increasing CRMP5 levels in control mice exacerbated memory decline after subthreshold stress treatment. Mechanistically, hippocampal CRMP5 suppression by regulating glucocorticoid receptor phosphorylation alleviates chronic stress-induced synaptic atrophy, disruption of AMPA receptor trafficking, and cytokine storms. Our findings show that hippocampal CRMP5 accumulation through GR activation disrupts synaptic plasticity, impedes AMPAR trafficking, and triggers cytokine release, thus playing a critical role in chronic stress-induced cognitive deficits.

Neuroprotective Effects of Lactobacillus plantarum PS128 in a Mouse Model of Parkinson's Disease: The Role of Gut Microbiota and MicroRNAs.

Parkinson's disease (PD) is a neurodegenerative disease characterized by motor deficits and marked neuroinflammation in various brain regions. The pathophysiology of PD is complex and mounting evidence has suggested an association with the dysregulation of microRNAs (miRNAs) and gut dysbiosis. Using a rotenone-induced PD mouse model, we observed that administration of Lactobacillus plantarum PS128 (PS128) significantly improved motor deficits in PD-like mice, accompanied by an increased level of dopamine, reduced dopaminergic neuron loss, reduced microglial activation, reduced levels of inflammatory factors, and enhanced expression of neurotrophic factor in the brain. Notably, the inflammation-related expression of miR-155-5p was significantly upregulated in the proximal colon, midbrain, and striatum of PD-like mice. PS128 reduced the level of miR-155-5p, whereas it increased the expression of suppressor of cytokine signaling 1 (SOCS1), a direct target of miR-155-5p and a critical inhibitor of the inflammatory response in the brain. Alteration of the fecal microbiota in PD-like mice was partially restored by PS128 administration. Among them, Bifidobacterium, Ruminiclostridium_6, Bacteroides, and Alistipes were statistically correlated with the improvement of rotenone-induced motor deficits and the expression of miR-155-5p and SOCS1. Our findings suggested that PS128 ameliorates motor deficits and exerts neuroprotective effects by regulating the gut microbiota and miR-155-5p/SOCS1 pathway in rotenone-induced PD-like mice.

A network analysis of self-reported psychoneurological symptoms in patients with head and neck cancer undergoing intensity-modulated radiotherapy.

BACKGROUND: Patients with head and neck cancer experience psychoneurological symptoms (PNS) (i.e., depression, fatigue, sleep disturbance, pain, and cognitive dysfunction) during intensity-modulated radiotherapy (IMRT) that decrease their functional status, quality of life, and survival rates. The purpose of this study was to examine and visualize the relationships among PNS within networks over time and evaluate for demographic and clinical characteristics associated with symptom networks. METHODS: A total of 172 patients (mean age, 59.8 ± 9.9 years; 73.8%, male; 79.4%, White) completed symptom questionnaires four times, namely, before IMRT (T1), 1 month (T2), 3 months (T3), and 12 months (T4) post IMRT. Network analysis was used to examine the symptom-symptom relationships among PNS. Centrality indices, including strength, closeness, and betweenness, were used to describe the degrees of symptom network interconnections. Network comparison test was used to assess the differences between two symptom networks. RESULTS: Depression was associated with the other four symptoms, and fatigue was associated with the other three symptoms across the four assessments. Based on the centrality indices, depression (rstrength  = 1.3-1.4, rcloseness  = 0.06-0.08, rbetweeness  = 4-10) was the core symptom in all symptom networks, followed by fatigue. Female gender, higher levels of stress, and no alcohol use were associated with stronger symptom networks in network global strength before IMRT. CONCLUSION: Network analysis provides a novel approach to gain insights into the relationships among self-reported PNS and identify the core symptoms and associated characteristics. Clinicians may use this information to develop symptom management interventions that target core symptoms and interconnections within a network. LAY SUMMARY: This study describes the symptom-symptom relationships for five common symptoms in patients with head and neck cancer receiving radiotherapy. Depression and fatigue appeared to be two core symptoms that were connected with sleep disturbance, pain, and cognitive dysfunction within a network. Several characteristics (i.e., female, higher stress, no alcohol use) were associated with stronger symptom networks.

Nursing Students From China and the United States: Learning Together Through Virtual Simulation.

AIM: The purpose of this project was to connect nursing students from schools of nursing in China and the United States for colearning using virtual simulations. BACKGROUND: With technology and international partnerships, nursing programs can offer global education without students traveling to other countries. METHOD: Virtual simulations were produced by each school for the project. Students completed them in two synchronous 1.5-hour virtual sessions, one month apart. At the end of each session, students completed the Simulation Effectiveness Tool-Modified and the Nurses Clinical Reasoning Scale. RESULTS: Scores on the Simulation Effectiveness Tool-Modified ranged from 75.0 percent to 100 percent on Simulation 1 (video vignettes focused on prioritization) and 88.9 percent to 100 percent on Simulation 2 (computer-based obstetrics case). Most students strongly agreed or agreed that the simulation improved their clinical reasoning skills. CONCLUSION: Virtual simulations allowed students to learn together and develop an awareness of differences in nursing practices across countries.

Distinct profiles of multiple co-occurring symptoms in patients with gastrointestinal cancers receiving chemotherapy.

PURPOSE: Identify subgroups of gastrointestinal (GI) cancer patients with distinct multiple co-occurring symptom profiles and evaluate for differences among these subgroups in demographic and clinical characteristics and quality of life (QOL) outcomes. METHODS: Patients with GI cancers (n = 399) completed the Memorial Symptom Assessment Scale (MSAS) that was used to assess for multiple co-occurring symptoms. Latent class analysis (LCA) was used to identify subgroups of patients with distinct symptom profiles using symptom occurrence ratings. Differences in demographic and clinical characteristics and QOL outcomes among the subgroups were evaluated using parametric and nonparametric tests. RESULTS: All Low (36.6%), Moderate (49.4%), and All High (14.0%) classes were identified. Compared to the All Low class, patients in the other two classes were significantly younger and were more likely to report depression and back pain. Compared to the other two classes, patients in the All High class had fewer years of education and a higher number of comorbidities. Significant differences were found among the three classes for comorbidity burden and total number of MSAS symptoms (i.e., All Low < Moderate < All High), as well as for performance status (i.e., All Low > Moderate > All High). A higher symptom burden was associated with poorer QOL outcomes. CONCLUSIONS: The first study to identify subgroups of patients with GI cancers based on distinct symptom profiles. LCA allowed for the identification of risk factors associated with a higher symptom burden. Clinicians can use this information to identify high-risk patients and develop personalized symptom management interventions.

A method for systematic mapping of protein lysine methylation identifies functions for HP1ß in DNA damage response.

Lysine methylation occurs on both histone and nonhistone proteins. However, our knowledge on the prevalence and function of nonhistone protein methylation is poor. We describe an approach that combines peptide array, bioinformatics, and mass spectrometry to systematically identify lysine methylation sites and map methyllysine-driven protein-protein interactions. Using this approach, we identified a high-confidence and high-resolution interactome of the heterochromatin protein 1ß (HP1ß) and uncovered, simultaneously, numerous methyllysine sites on nonhistone proteins. We found that HP1ß binds to DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and regulates its localization to double-strand breaks (DSBs) during DNA damage response (DDR). Mutation of the methylation sites in DNA-PKcs or depletion of HP1ß in cells caused defects in DDR. Furthermore, we showed that the methylation of DNA-PKcs and many other proteins in the HP1ß interactome undergoes large changes in response to DNA damage, indicating that Lys methylation is a highly dynamic posttranslational modification.

The association between immune-related adverse events and survival outcomes in Asian patients with advanced melanoma receiving anti-PD-1 antibodies.

BACKGROUND: The association between immune-related adverse events (irAEs) and survival outcomes in patients with advanced melanoma receiving therapy with immune checkpoint inhibitors (ICIs) has not been well established, particularly in Asian melanoma. METHODS: We retrospectively reviewed 49 melanoma patients undergoing therapy with ICIs (anti-PD-1 monotherapy), and analyzed the correlation between irAEs and clinical outcomes including progression-free survival (PFS) and overall survival (OS). RESULTS: Overall, the patients who experienced grade 1-2 irAEs had longer PFS (median PFS, 4.6 vs. 2.5 months; HR, 0.52; 95% CI: 0.27-0.98; p = 0.042) and OS (median OS, 15.2 vs. 5.7 months; HR, 0.50; 95% CI: 0.24-1.02; p = 0.058) than the patients who did not experience irAEs. Regarding the type of irAE, the patients with either skin/vitiligo or endocrine irAEs showed better PFS (median PFS, 6.1 vs. 2.7 months; HR, 0.40, 95% CI: 0.21-0.74; p = 0.003) and OS (median OS, 18.7 vs. 4.5 months; HR, 0.34, 95% CI: 0.17-0.69, p = 0.003) than patients without any of these irAEs. CONCLUSIONS: Melanoma patients undergoing anti-PD-1 monotherapy and experiencing mild-to-moderate irAEs (grade 1-2), particularly skin (vitiligo)/endocrine irAEs had favorable survival outcomes. Therefore, the association between irAEs and the clinical outcomes in melanoma patients undergoing anti-PD-1 ICIs may be severity and type dependent.

Factors impacting on discordance with treatment plan in head and neck cancer patients: a retrospective, population-based cohort study.

PURPOSE: The aims of this study were to identify the factors and reasons impacting discordance with the treatment plan in head and neck cancer (HNC) patients and compare the differences between the concordance group and the discordance group. METHODS: This secondary analysis was conducted from population-based data from Taiwan collected from January 1, 2016, to June 30, 2018. Logistic regression analysis was used to identify the factors related to discordance with the treatment plan. RESULTS: We examined 1095 HNC patients, 12.1% of whom were discordant with treatment. Patients with advanced cancer stage, old age, and treatment plans of best supportive care (BSC) or surgery combined with radiation (RT), chemotherapy (CT), or chemoradiation (CCRT) were more likely to have discordance with their treatment plan. Of the 133 patients who were discordant with their treatment plan, the top reasons were as follows: "patients or their family considered patients' poor physical condition (chronic disease or unstable systemic disease), difficulty in enduring any condition likely to cause physical discomfort from disease treatment," "inconvenient transportation," and "disease progression." CONCLUSIONS: Patients' cancer stage, age, and types of treatment plans recommended significantly influenced discordance with treatment plan. Poor physical condition was the major reason for discordance with the treatment plan. Patients in the concordance group were significantly more likely than those in the discordance group to be younger than 65 years, have less advanced cancer stage, and be recommended to receive surgery rather than any other regimen. Multidisciplinary team care can help patients make positive decisions about treatment.

PIDD mediates the association of DNA-PKcs and ATR at stalled replication forks to facilitate the ATR signaling pathway.

The DNA-dependent protein kinase (DNA-PK), consisting of the DNA binding Ku70/80 heterodimer and the catalytic subunit DNA-PKcs, has been well characterized in the non-homologous end-joining mechanism for DNA double strand break (DSB) repair and radiation resistance. Besides playing a role in DSB repair, DNA-PKcs is required for the cellular response to replication stress and participates in the ATR-Chk1 signaling pathway. However, the mechanism through which DNA-PKcs is recruited to stalled replication forks is still unclear. Here, we report that the apoptosis mediator p53-induced protein with a death domain (PIDD) is required to promote DNA-PKcs activity in response to replication stress. PIDD is known to interact with PCNA upon UV-induced replication stress. Our results demonstrate that PIDD is required to recruit DNA-PKcs to stalled replication forks through direct binding to DNA-PKcs at the N' terminal region. Disruption of the interaction between DNA-PKcs and PIDD not only compromises the ATR association and regulation of DNA-PKcs, but also the ATR signaling pathway, intra-S-phase checkpoint and cellular resistance to replication stress. Taken together, our results indicate that PIDD, but not the Ku heterodimer, mediates the DNA-PKcs activity at stalled replication forks and facilitates the ATR signaling pathway in the cellular response to replication stress.

Response evaluation for immunotherapy through semi-automatic software based on RECIST 1.1, irRC, and iRECIST criteria: comparison with subjective assessment.

BACKGROUND: Pseudoprogression is difficult to diagnose in patients undergoing immunotherapy. Subjective response assessment is still common in clinical practice. PURPOSE: To evaluate the differences between response evaluation criteria in solid tumors version 1.1 (RECIST 1.1), immune-related response criteria (irRC), and modified RECIST 1.1 for immunotherapy (iRECIST) through semi-automatic software, and to compare iRECIST-based response evaluation with subjective assessment. MATERIAL AND METHODS: The best overall response of each patient based on RECIST 1.1, irRC, and iRECIST was determined on CT scans through semi-automatic software and the differences between the criteria were evaluated. Criteria-based response evaluation through semi-automatic software was compared with subjective assessment on radiology report by correlating the best overall response to overall survival. RESULTS: A total of 21 patients were included (five patients with melanoma, 12 patients with non-small-cell lung cancer, and four patients with hepatocellular carcinoma). Two patients with progressive disease by RECIST 1.1 but non-progressive disease by irRC and iRECIST eventually experienced tumor response and had favorable outcomes, indicating pseudoprogression. The survival difference between patients with non-progressive disease and progressive disease was better stratified through iRECIST-based response evaluation (P = 0.078) than that through subjective assessment (P = 0.501). CONCLUSION: Pseudoprogression in immunotherapy may be captured through semi-automatic software utilizing irRC or iRECIST criteria. iRECIST-based response evaluation may provide a better survival stratification compared with subjective assessment.

Colorectal cancer in Taiwan: A case-control retrospective analysis of the impact of a case management programme on refusal and discontinuation of treatment.

AIMS: The purposes of this study were to identify the impact of a case management programme on the related factors of refusing treatment or discontinuing treatment in Taiwanese colorectal cancer patients. BACKGROUND: Side effects of anti-cancer treatments are associated with refusing treatment and discontinuing treatment. DESIGN: This case-control study, longitudinal database and secondary analysis of population-based data was conducted from 2009-2012. METHODS: Logistic regression was used to reveal the factors related to refusing or discontinuing treatment. RESULTS: Of the 68 patients who refused treatment, the top reasons for refusing treatment were patients or their family considered the patients poor physical condition, difficulty in enduring any condition likely to cause physical discomfort from the disease treatment, selected complementary and alternative medicine, patients or their families or friends experienced negative treatment effects and worried about the side effects of treatment, older age, poor family support and lost contact. Of the 278 patients who discontinued treatment, the most common reasons for discontinuing treatment were patients or their families or friends experienced negative treatment effects and worried about the side effects of treatment, inconvenient transportation, patients or their family considered the patients poor physical condition, difficulty in enduring any condition likely to cause physical discomfort from the disease treatment, poor treatment effect and selected complementary and alternative medicine. CONCLUSION: Case managers can provide positive communication and available resources in relation to cancer treatment. A case management programme can help patients cope with the difficulties encountered during the treatment period.

DNA-PKcs phosphorylates hnRNP-A1 to facilitate the RPA-to-POT1 switch and telomere capping after replication.

The heterogeneous nuclear ribonucleoprotein A1 (hnRNP-A1) has been implicated in telomere protection and telomerase activation. Recent evidence has further demonstrated that hnRNP-A1 plays a crucial role in maintaining newly replicated telomeric 3' overhangs and facilitating the switch from replication protein A (RPA) to protection of telomeres 1 (POT1). The role of hnRNP-A1 in telomere protection also involves DNA-dependent protein kinase catalytic subunit (DNA-PKcs), although the detailed regulation mechanism has not been clear. Here we report that hnRNP-A1 is phosphorylated by DNA-PKcs during the G2 and M phases and that DNA-PK-dependent hnRNP-A1 phosphorylation promotes the RPA-to-POT1 switch on telomeric single-stranded 3' overhangs. Consequently, in cells lacking hnRNP-A1 or DNA-PKcs-dependent hnRNP-A1 phosphorylation, impairment of the RPA-to-POT1 switch results in DNA damage response at telomeres during mitosis as well as induction of fragile telomeres. Taken together, our results indicate that DNA-PKcs-dependent hnRNP-A1 phosphorylation is critical for capping of the newly replicated telomeres and prevention of telomeric aberrations.

FANCD2 and REV1 cooperate in the protection of nascent DNA strands in response to replication stress.

REV1 is a eukaryotic member of the Y-family of DNA polymerases involved in translesion DNA synthesis and genome mutagenesis. Recently, REV1 is also found to function in homologous recombination. However, it remains unclear how REV1 is recruited to the sites where homologous recombination is processed. Here, we report that loss of mammalian REV1 results in a specific defect in replication-associated gene conversion. We found that REV1 is targeted to laser-induced DNA damage stripes in a manner dependent on its ubiquitin-binding motifs, on RAD18, and on monoubiquitinated FANCD2 (FANCD2-mUb) that associates with REV1. Expression of a FANCD2-Ub chimeric protein in RAD18-depleted cells enhances REV1 assembly at laser-damaged sites, suggesting that FANCD2-mUb functions downstream of RAD18 to recruit REV1 to DNA breaks. Consistent with this suggestion we found that REV1 and FANCD2 are epistatic with respect to sensitivity to the double-strand break-inducer camptothecin. REV1 enrichment at DNA damage stripes also partially depends on BRCA1 and BRCA2, components of the FANCD2/BRCA supercomplex. Intriguingly, analogous to FANCD2-mUb and BRCA1/BRCA2, REV1 plays an unexpected role in protecting nascent replication tracts from degradation by stabilizing RAD51 filaments. Collectively these data suggest that REV1 plays multiple roles at stalled replication forks in response to replication stress.

Health-related quality of life and satisfaction with case management in cancer survivors.

AIMS AND OBJECTIVES: To (i) investigate the characteristics of health-related quality of life and satisfaction with case management and (ii) to identify factors associated with health-related quality of life in cancer survivors. BACKGROUND: The level of health-related quality of life can reflect treatment efficacy and satisfaction with cancer care. DESIGN: A cross-sectional study design was adopted. METHODS: Subjects from the outpatient setting of a cancer centre in northern Taiwan were recruited by consecutive sampling. A set of questionnaires were employed, including a background information form, case management service satisfaction survey (CMSS) and The European Quality of Life Scale (EQ-5D). Descriptive statistics were used to examine levels of health-related quality of life and satisfaction with case management. Pearson's correlation was used to identify relationships between treatment characteristics, satisfaction with case management and health-related quality of life. Multiple stepwise regression was used to identify factors associated with health-related quality of life. RESULTS: A total of 252 cancer patients were recruited. The three lowest scores for items of health-related quality of life were mobility, self-care and usual activities. Cancer survivors with higher mobility, less pain and discomfort, and lower anxiety and depression were more likely to have better health-related quality of life. CONCLUSION: Mobility, pain and discomfort, and anxiety and depression are important predictive factors of high health-related quality of life in cancer survivors. RELEVANCE TO CLINICAL PRACTICE: In clinical care, patients' physical mobility, pain and discomfort, and anxiety and depression are important indicators of health-related quality of life. Case managers should include self-care and symptom management into survivorship care plans to improve health-related quality of life during survival after treatment concludes.

DNA-PKcs is required to maintain stability of Chk1 and Claspin for optimal replication stress response.

The ataxia telangiectasia mutated and Rad3-related (ATR)-checkpoint kinase 1 (Chk1) axis is the major signaling pathway activated in response to replication stress and is essential for the intra-S checkpoint. ATR phosphorylates and activates a number of molecules to coordinate cell cycle progression. Chk1 is the major effector downstream from ATR and plays a critical role in intra-S checkpoint on replication stress. Activation of Chk1 kinase also requires its association with Claspin, an adaptor protein essential for Chk1 protein stability, recruitment and ATR-dependent Chk1 phosphorylation. We have previously reported that, on replication stress, the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) is rapidly phosphorylated by ATR at the stalled replication forks and is required for cellular resistance to replication stresses although the impact of DNA-PKcs onto the ATR signaling pathway remains elusive. Here we report that ATR-dependent Chk1 phosphorylation and Chk1 signaling are compromised in the absence of DNA-PKcs. Our investigation reveals that DNA-PKcs is required to maintain Chk1-Claspin complex stability and transcriptional regulation of Claspin expression. The impaired Chk1 activity results in a defective intra-S checkpoint response in DNA-PKcs-deficient cells. Taken together, these results suggest that DNA-PKcs, in addition to its direct role in DNA damage repair, facilitates ATR-Chk1 signaling pathway in response to replication stress.

Reliability and responsiveness of the activities of daily living computerized adaptive testing system in patients with stroke.

OBJECTIVE: To examine the intrarater reliability, interrater reliability, and responsiveness of the Activities of Daily Living Computerized Adaptive Testing system (ADL CAT) in patients with stroke. DESIGN: One repeated-measures design (at an interval of 7d) was used to examine the intrarater reliability and interrater reliability of the ADL CAT. For the responsiveness study, participants were assessed with the ADL CAT at admission to the rehabilitation ward and at discharge from the hospital. SETTING: Eight rehabilitation units. PARTICIPANTS: Three different (nonoverlapping) groups of patients (N=157) were recruited. Fifty-five and 42 outpatients with chronic stroke participated in the intrarater and interrater reliability studies, respectively; 60 inpatients who had recently had a stroke participated in the responsiveness study. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE ADL CAT RESULTS: The intraclass correlation coefficient values were .94 and .80 for the ADL CAT in the intrarater reliability and interrater reliability studies, respectively. The classical test theory-based minimal detectable change values were 6.5 and 9.5 for the ADL CAT in the intrarater reliability and interrater reliability studies, respectively. The Kazis' effect size and standardized response mean of the ADL CAT were moderate (.62-.73). CONCLUSIONS: The ADL CAT has good intrarater reliability and interrater reliability in outpatients with chronic stroke, and sufficient responsiveness in inpatients with stroke undergoing inpatient rehabilitation. Further investigations on the responsiveness of the ADL CAT in outpatients are needed to obtain more evidence on the utility of the ADL CAT.