Loss-of-function mutations in hematopoietic transcription factors including PAX5 occur in most cases of B-progenitor acute lymphoblastic leukemia (B-ALL), a disease characterized by the accumulation ...of undifferentiated lymphoblasts. Although PAX5 mutation is a critical driver of B-ALL development in mice and humans, it remains unclear how its loss contributes to leukemogenesis and whether ongoing PAX5 deficiency is required for B-ALL maintenance. Here we used transgenic RNAi to reversibly suppress endogenous Pax5 expression in the hematopoietic compartment of mice, which cooperates with activated signal transducer and activator of transcription 5 (STAT5) to induce B-ALL. In this model, restoring endogenous Pax5 expression in established B-ALL triggers immunophenotypic maturation and durable disease remission by engaging a transcriptional program reminiscent of normal B-cell differentiation. Notably, even brief Pax5 restoration in B-ALL cells causes rapid cell cycle exit and disables their leukemia-initiating capacity. These and similar findings in human B-ALL cell lines establish that Pax5 hypomorphism promotes B-ALL self-renewal by impairing a differentiation program that can be re-engaged despite the presence of additional oncogenic lesions. Our results establish a causal relationship between the hallmark genetic and phenotypic features of B-ALL and suggest that engaging the latent differentiation potential of B-ALL cells may provide new therapeutic entry points.
Patients with advanced heart failure have improved survival rates and quality of life when treated with implanted pulsatile-flow left ventricular assist devices as compared with medical therapy. New ...continuous-flow devices are smaller and may be more durable than the pulsatile-flow devices.
In this randomized trial, we enrolled patients with advanced heart failure who were ineligible for transplantation, in a 2:1 ratio, to undergo implantation of a continuous-flow device (134 patients) or the currently approved pulsatile-flow device (66 patients). The primary composite end point was, at 2 years, survival free from disabling stroke and reoperation to repair or replace the device. Secondary end points included survival, frequency of adverse events, the quality of life, and functional capacity.
Preoperative characteristics were similar in the two treatment groups, with a median age of 64 years (range, 26 to 81), a mean left ventricular ejection fraction of 17%, and nearly 80% of patients receiving intravenous inotropic agents. The primary composite end point was achieved in more patients with continuous-flow devices than with pulsatile-flow devices (62 of 134 46% vs. 7 of 66 11%; P<0.001; hazard ratio, 0.38; 95% confidence interval, 0.27 to 0.54; P<0.001), and patients with continuous-flow devices had superior actuarial survival rates at 2 years (58% vs. 24%, P=0.008). Adverse events and device replacements were less frequent in patients with the continuous-flow device. The quality of life and functional capacity improved significantly in both groups.
Treatment with a continuous-flow left ventricular assist device in patients with advanced heart failure significantly improved the probability of survival free from stroke and device failure at 2 years as compared with a pulsatile device. Both devices significantly improved the quality of life and functional capacity. (ClinicalTrials.gov number, NCT00121485.)
Despite therapeutic innovations, metastatic colorectal cancer (mCRC) is still characterized by poor prognosis and few molecular markers predict the risk of progression. Polycomb group genes (PcGs) ...are epigenetic modifiers involved in tumor suppressor gene silencing. PcG member EZH2 mediates gene silencing through histone-H3 lysine-27 methylation. In colorectal cancer (CRC), EZH2 overexpression predicts shorter survival. Recently, four EZH2 single-nucleotide polymorphisms (SNPs) have been described. The present study was aimed at evaluating the correlation between EZH2 SNPs and outcome parameters in mCRC patients.
DNA was extracted from blood samples of 110 mCRC patients treated with first-line 5-fluorouracil, folinic acid, irinotecan (FOLFIRI) and bevacizumab. Genotyping was carried out by real-time PCR. Genotype was used to predict objective response, progression-free survival (PFS) and overall survival (OS). EZH2 messenger RNA levels were evaluated on lymphocytes of a parallel cohort of 50 CRC patients.
One allelic variant (rs3757441 C/C versus C/T or T/T) was significantly associated with shorter PFS and OS (P < 0.01 and P < 0.05, respectively). At multivariate analysis, the same variant resulted an independent predictor of PFS and OS (P < 0.05). The C/C variant was associated with significantly higher EZH2 expression (P < 0.05).
An EZH2 SNP may be useful to predict clinical outcome in mCRC patients.
Signal transducer and activator of transcription 5 (STAT5) activation occurs frequently in human progenitor B-cell acute lymphoblastic leukemia (B-ALL). To identify gene alterations that cooperate ...with STAT5 activation to initiate leukemia, we crossed mice expressing a constitutively active form of STAT5 (Stat5b-CA) with mice in which a mutagenic Sleeping Beauty transposon (T2/Onc) was mobilized only in B cells. Stat5b-CA mice typically do not develop B-ALL (<2% penetrance); in contrast, 89% of Stat5b-CA mice in which the T2/Onc transposon had been mobilized died of B-ALL by 3 months of age. High-throughput sequencing approaches were used to identify genes frequently targeted by the T2/Onc transposon; these included Sos1 (74%), Kdm2a (35%), Jak1 (26%), Bmi1 (19%), Prdm14 or Ncoa2 (13%), Cdkn2a (10%), Ikzf1 (8%), Caap1 (6%) and Klf3 (6%). Collectively, these mutations target three major cellular processes: (i) the Janus kinase/STAT5 pathway (ii) progenitor B-cell differentiation and (iii) the CDKN2A tumor-suppressor pathway. Transposon insertions typically resulted in altered expression of these genes, as well as downstream pathways including STAT5, extracellular signal-regulated kinase (Erk) and p38. Importantly, expression of Sos1 and Kdm2a, and activation of p38, correlated with survival, further underscoring the role these genes and associated pathways have in B-ALL.
Highlights • Although left ventricular assist device (LVAD) therapy improves survival, ~20% of recipients continue to suffer from significant functional limitations. • With the use of data from the ...Heartmate II bridge-to-transplant and destination therapy clinical trials, baseline determinants of quality of life (QOL) and functional capacity (FC) response were investigated. • Baseline preoperative correlates of RV dysfunction as well as history of diabetes were associated with reduced FC response to LVAD therapy, and history of diabetes and COPD were independently associated with reduced QOL response. • Positive QOL and FC responses were both associated with improved survival. • Comorbid conditions, including diabetes, COPD, and right heart failure, may limit response to LVAD therapy and should be considered during patient selection.
Combination antifungal therapy (amphotericin B deoxycholate and flucytosine) is the recommended treatment for cryptococcal meningitis but has not been shown to reduce mortality, as compared with ...amphotericin B alone. We performed a randomized, controlled trial to determine whether combining flucytosine or high-dose fluconazole with high-dose amphotericin B improved survival at 14 and 70 days.
We conducted a randomized, three-group, open-label trial of induction therapy for cryptococcal meningitis in patients with human immunodeficiency virus infection. All patients received amphotericin B at a dose of 1 mg per kilogram of body weight per day; patients in group 1 were treated for 4 weeks, and those in groups 2 and 3 for 2 weeks. Patients in group 2 concurrently received flucytosine at a dose of 100 mg per kilogram per day for 2 weeks, and those in group 3 concurrently received fluconazole at a dose of 400 mg twice daily for 2 weeks.
A total of 299 patients were enrolled. Fewer deaths occurred by days 14 and 70 among patients receiving amphotericin B and flucytosine than among those receiving amphotericin B alone (15 vs. 25 deaths by day 14; hazard ratio, 0.57; 95% confidence interval CI, 0.30 to 1.08; unadjusted P=0.08; and 30 vs. 44 deaths by day 70; hazard ratio, 0.61; 95% CI, 0.39 to 0.97; unadjusted P=0.04). Combination therapy with fluconazole had no significant effect on survival, as compared with monotherapy (hazard ratio for death by 14 days, 0.78; 95% CI, 0.44 to 1.41; P=0.42; hazard ratio for death by 70 days, 0.71; 95% CI, 0.45 to 1.11; P=0.13). Amphotericin B plus flucytosine was associated with significantly increased rates of yeast clearance from cerebrospinal fluid (-0.42 log10 colony-forming units CFU per milliliter per day vs. -0.31 and -0.32 log10 CFU per milliliter per day in groups 1 and 3, respectively; P<0.001 for both comparisons). Rates of adverse events were similar in all groups, although neutropenia was more frequent in patients receiving a combination therapy.
Amphotericin B plus flucytosine, as compared with amphotericin B alone, is associated with improved survival among patients with cryptococcal meningitis. A survival benefit of amphotericin B plus fluconazole was not found. (Funded by the Wellcome Trust and the British Infection Society; Controlled-Trials.com number, ISRCTN95123928.).
Crude oil released from the Deepwater Horizon disaster into the Gulf of Mexico posed potential impacts to infaunal invertebrates inhabiting near shore habitats. The effects of sediment-associated ...weathered slick oil on the amphipod Leptocheirus plumulosus was assessed using 28-d exposures to total PAH sediment concentrations ranging from 0.3 to 24mg/kg (sum of 50 PAHs or tPAH50). Survival and growth rate were significantly decreased in the 2.6, 11.4 and 24.2mg/kg treatments, but only growth in 5.5mg/kg. Offspring production was dramatically decreased but was variable and significantly different only for 24.2mg/kg. The concentrations associated with 20% decreases relative to reference were 1.05 (95% CI=0–2.89) mg/kg tPAH50 for growth rate and 0.632 (95% CI=0.11–2.15) mg/kg tPAH50 for offspring production. The concentrations of PAHs affecting amphipods are within the range of concentrations measured in marsh areas reportedly impacted by DWH oil after its release.
•Amphipods exposed to sediment mixed with oil from the Deepwater Horizon (DWH) spill.•28-d exposures assessed effects on survival, growth and reproduction.•Growth was significantly reduced at 2.6mg/kg total PAHs and higher concentrations.•The concentrations associated with a 20% decrease in reproduction was 0.632mg/kg total PAHs.
The aim of this study was to determine whether results with the HeartMate (HM) II left ventricular assist device (LVAD) (Thoratec Corporation, Pleasanton, California) in a commercial setting are ...comparable to other available devices for the same indication.
After a multicenter pivotal clinical trial conducted from 2005 to 2008, the U.S. Food and Drug Administration approved the HM II LVAD for bridge to transplantation (BTT). A post-approval study was required by the U.S. Food and Drug Administration to determine whether results with the device in a commercial setting are comparable to other available devices for the same indication.
The study was a prospective evaluation of the first 169 consecutive HM II patients enrolled in the national INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) who were listed for transplant or likely to be listed. Patients were enrolled from April through August 2008 at 77 U.S. centers and followed for at least 1 year after implant. A comparison group (COMP) included all patients (n = 169 at 27 centers) enrolled in the INTERMACS registry with other types of LVADs (79% HeartMate XVE, 21% Implantable Ventricular Assist Device Thoratec Corporation) for the same BTT indication in the same time period. Survival rates, adverse events, and quality of life with the EuroQol EQ-5D visual analog scale were obtained in the INTERMACS registry.
Baseline characteristics were similar, but creatinine and blood urea nitrogen were lower in the HM II versus COMP groups, and there were fewer patients in the highest-risk INTERMACS patient profile Number 1 (24% for HM II vs. 39% for COMP). Adverse event rates were similar or lower for HM II versus COMP for all events. Bleeding was the most frequent adverse event for both groups (1.44 vs. 1.79 events/patient-year). Operative 30-day mortality for HM II was 4% versus 11% for COMP. The percentage of patients reaching transplant, cardiac recovery, or ongoing LVAD support by 6 months was 91% for HM II and 80% for COMP, and the Kaplan-Meier survival for patients remaining on support at 1 year was 85% for HM II versus 70% for COMP. Quality of life was significantly improved at 3 months of support and sustained through 12 months in both groups compared with baseline.
The results in a post-market approval, actual patient care setting BTT population support the original findings from the pivotal clinical trial regarding the efficacy and risk profile of the HM II LVAD. These data suggest that dissemination of this technology after approval has been associated with continued excellent results.
Quaternary benzylic centers are accessed with high atom and step economy by Ir-catalyzed alkene hydroarylation. These studies provide unique examples of the use of non-polarized 1,1-disubstituted ...alkenes in branch selective Murai-type hydro(hetero)arylations. Detailed mechanistic studies have been undertaken, and these indicate that the first irreversible step is the demanding alkene carbometallation process. Structure-reactivity studies show that the efficiency of this is critically dependent on key structural features of the ligand. Computational studies have been undertaken to rationalize this experimental data, showing how more sterically demanding ligands reduce the reaction barrier
predistortion of the reacting intermediate. The key insight disclosed here will underpin the ongoing development of increasingly sophisticated branch selective Murai hydroarylations.
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