An ATP and Oxalate Generating Variant Tricarboxylic Acid Cycle Counters Aluminum Toxicity in Pseudomonas fluorescens

Although the tricarboxylic acid (TCA) cycle is essential in almost all aerobic organisms, its precise modulation and integration in global cellular metabolism is not fully understood. Here, we report on an alternative TCA cycle uniquely aimed at generating ATP and oxalate, two metabolites critical for the survival of Pseudomonas fluorescens. The upregulation of isocitrate lyase (ICL) and acylating glyoxylate dehydrogenase (AGODH) led to the enhanced synthesis of oxalate, a dicarboxylic acid involved in the immobilization of aluminum (Al). The increased activity of succinyl-CoA synthetase (SCS) and oxalate CoA-transferase (OCT) in the Al-stressed cells afforded an effective route to ATP synthesis from oxalyl-CoA via substrate level phosphorylation. This modified TCA cycle with diminished efficacy in NADH production and decreased CO2-evolving capacity, orchestrates the synthesis of oxalate, NADPH, and ATP, ingredients pivotal to the survival of P. fluorescens in an Al environment. The channeling of succinyl-CoA towards ATP formation may be an important function of the TCA cycle during anaerobiosis, Fe starvation and O2-limited conditions

Brentuximab vedotin in combination with rituximab, cyclophosphamide, doxorubicin, and prednisone as frontline treatment for patients with CD30-positive B-cell lymphomas

We conducted a phase I/II multicenter trial using 6 cycles of brentuximab vedotin (BV) in combination with rituximab, cyclophosphamide, doxorubicin, and prednisone (R-CHP) for treatment of patients with CD30-positive (+) B-cell lymphomas. Thirty-one patients were evaluable for toxicity and 29 for efficacy including 22 with primary mediastinal B-cell lymphoma (PMBCL), 5 with diffuse large B-cell lymphoma (DLBCL), and 2 with gray zone lymphoma (GZL). There were no treatment-related deaths; 32% of patients had non-hematological grade 3/4 toxicities. The overall response rate was 100% (95% CI: 88-100) with 86% (95% CI: 68-96) of patients achieving complete response at the end of systemic treatment. Consolidative radiation following end of treatment response assessment was permissible and used in 52% of all patients including 59% of patients with PMBCL. With a median follow-up of 30 months, the 2-year progression-free survival (PFS) and overall survival (OS) were 85% (95% CI: 66-94) and 100%, respectively. In the PMBCL cohort, 2-year PFS was 86% (95% CI: 62-95). In summary, BV-R-CHP with or without consolidative radiation is a feasible and active frontline regimen for CD30+ B-cell lymphomas (NCT01994850)

Primary Care Providers Are Vital to Carrying out Hepatitis C Screening

Background: Chronic Hepatitis C Virus (HCV) infection affects approximately 3 million Americans. The 1945-1965 birth cohort has the highest prevalence, estimated at 2%. In 2013, the United States Preventive Services Task Force (USPSTF) endorsed screening for HCV in this cohort with the goal of identifying cases and initiating treatment. However, a variety of obstacles to screening are suspected to contribute to low screening rates. This study evaluated the role of the primary care physician in completing recommended screening in an historically underserved community with a high prevalence of HCV. Methods: Individuals attending an August 2015 health exposition sponsored by the Rodham Institute completed an anonymous survey. The exposition was hosted in an urban setting where the population has historically been predominantly African American; currently 92% of residents identify as such. The survey included questions on demographic information, access to a PCP, insurance status, as well as knowledge of various topics related to Hepatitis C. Responses were excluded if they did not provide information on their history of screening. The university institutional review board approved the study. Statistical analysis was performed using Fisher’s exact test, with significance set at p\u3c0.05. Results: Ninety five responses were analyzed. Among them were 29 born in the 1945-1965 timeframe. All of members of this cohort reported having a primary physician and 27 (96.4%) had health insurance. Sixteen discussed HCV with their doctor and 12 of them (75.0%) were screened. Thirteen respondents had not discussed HCV; among them, three (23.1%) were tested for the virus. Having a discussion with the primary physician resulted in a significantly higher rate of HCV screening (p=0.0092). Conclusions: The primary care provider is vital to implementing preventive health recommendations including those related to HCV screening. Our study showed that in a high-prevalence, insured cohort, patients who had discussed HCV with their primary physician were three times more likely to have been screened for the infection. The population studied all had health insurance and a primary care provider, so health care was broadly accessible. The study also suggests that some recent USPSTF guidelines may not have penetrated into community primary care practices as the screening rates were suboptimal

MYCN recruits the nuclear exosome complex to RNA polymerase II to prevent transcription-replication conflicts

The MYCN oncoprotein drives the development of numerous neuroendocrine and pediatric tumors. Here we show that MYCN interacts with the nuclear RNA exosome, a 3'-5' exoribonuclease complex, and recruits the exosome to its target genes. In the absence of the exosome, MYCN-directed elongation by RNA polymerase II (RNAPII) is slow and non-productive on a large group of cell-cycle-regulated genes. During the S phase of MYCN-driven tumor cells, the exosome is required to prevent the accumulation of stalled replication forks and of double-strand breaks close to the transcription start sites. Upon depletion of the exosome, activation of ATM causes recruitment of BRCA1, which stabilizes nuclear mRNA decapping complexes, leading to MYCN-dependent transcription termination. Disruption of mRNA decapping in turn activates ATR, indicating transcription-replication conflicts. We propose that exosome recruitment by MYCN maintains productive transcription elongation during S phase and prevents transcription-replication conflicts to maintain the rapid proliferation of neuroendocrine tumor cells

Brentuximab vedotin plus AVD for Hodgkin lymphoma: incidence and management of peripheral neuropathy in a multisite cohort.

Brentuximab vedotin (BV) in combination with doxorubicin, vinblastine, and dacarbazine (AVD) is increasingly used for frontline treatment of stage III/IV classical Hodgkin lymphoma (cHL). Peripheral neuropathy (PN) was the most common and treatment-limiting side effect seen in clinical trials but has not been studied in a nontrial setting, in which clinicians may have different strategies for managing it. We conducted a multisite retrospective study to characterize PN in patients who received BV + AVD for newly diagnosed cHL. One hundred fifty-three patients from 10 US institutions were eligible. Thirty-four patients (22%) had at least 1 ineligibility criteria for ECHELON-1, including stage, performance status, and comorbidities. PN was reported by 80% of patients during treatment; 39% experienced grade (G) 1, 31% G2, and 10% G3. In total, BV was modified in 44% of patients because of PN leading to BV discontinuation in 23%, dose reduction in 17%, and temporary hold in 4%. With a median follow-up of 24 months, PN resolution was documented in 36% and improvement in 33% at the last follow-up. Two-year progression-free survival (PFS) for the advanced-stage patients was 82.7% (95% confidence interval [CI], 0.76-0.90) and overall survival was 97.4% (95% CI, 0.94-1.00). Patients who discontinued BV because of PN did not have inferior PFS. In the nontrial setting, BV + AVD was associated with a high incidence of PN. In our cohort, which includes patients who would not have been eligible for the pivotal ECHELON-1 trial, BV discontinuation rates were higher than previously reported, but 2-year outcomes remain comparable