Author Correction: Genome-wide CRISPR-Cas9 screening reveals ubiquitous T cell cancer targeting via the monomorphic MHC class I-related protein MR1.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Genome-wide CRISPR-Cas9 screening reveals ubiquitous T cell cancer targeting via the monomorphic MHC class I-related protein MR1.

Human leukocyte antigen (HLA)-independent, T cell-mediated targeting of cancer cells would allow immune destruction of malignancies in all individuals. Here, we use genome-wide CRISPR-Cas9 screening to establish that a T cell receptor (TCR) recognized and killed most human cancer types via the monomorphic MHC class I-related protein, MR1, while remaining inert to noncancerous cells. Unlike mucosal-associated invariant T cells, recognition of target cells by the TCR was independent of bacterial loading. Furthermore, concentration-dependent addition of vitamin B-related metabolite ligands of MR1 reduced TCR recognition of cancer cells, suggesting that recognition occurred via sensing of the cancer metabolome. An MR1-restricted T cell clone mediated in vivo regression of leukemia and conferred enhanced survival of NSG mice. TCR transfer to T cells of patients enabled killing of autologous and nonautologous melanoma. These findings offer opportunities for HLA-independent, pan-cancer, pan-population immunotherapies.

A cell state-specific metabolic vulnerability to GPX4-dependent ferroptosis in glioblastoma.

Glioma cells hijack developmental programs to control cell state. Here, we uncover a glioma cell state-specific metabolic liability that can be therapeutically targeted. To model cell conditions at brain tumor inception, we generated genetically engineered murine gliomas, with deletion of p53 alone (p53) or with constitutively active Notch signaling (N1IC), a pathway critical in controlling astrocyte differentiation during brain development. N1IC tumors harbored quiescent astrocyte-like transformed cell populations while p53 tumors were predominantly comprised of proliferating progenitor-like cell states. Further, N1IC transformed cells exhibited increased mitochondrial lipid peroxidation, high ROS production and depletion of reduced glutathione. This altered mitochondrial phenotype rendered the astrocyte-like, quiescent populations more sensitive to pharmacologic or genetic inhibition of the lipid hydroperoxidase GPX4 and induction of ferroptosis. Treatment of patient-derived early-passage cell lines and glioma slice cultures generated from surgical samples with a GPX4 inhibitor induced selective depletion of quiescent astrocyte-like glioma cell populations with similar metabolic profiles. Collectively, these findings reveal a specific therapeutic vulnerability to ferroptosis linked to mitochondrial redox imbalance in a subpopulation of quiescent astrocyte-like glioma cells resistant to standard forms of treatment.

Adjunctive Intravenous Argatroban or Eptifibatide for Ischemic Stroke.

BACKGROUND: Intravenous thrombolysis is a standard treatment of acute ischemic stroke. The efficacy and safety of combining intravenous thrombolysis with argatroban (an anticoagulant agent) or eptifibatide (an antiplatelet agent) are unclear. METHODS: We conducted a phase 3, three-group, adaptive, single-blind, randomized, controlled clinical trial at 57 sites in the United States. Patients with acute ischemic stroke who had received intravenous thrombolysis within 3 hours after symptom onset were assigned to receive intravenous argatroban, eptifibatide, or placebo within 75 minutes after the initiation of thrombolysis. The primary efficacy outcome, the utility-weighted 90-day modified Rankin scale score (range, 0 to 10, with higher scores reflecting better outcomes), was assessed by means of centralized adjudication. The primary safety outcome was symptomatic intracranial hemorrhage within 36 hours after randomization. RESULTS: A total of 514 patients were assigned to receive argatroban (59 patients), eptifibatide (227 patients), or placebo (228 patients). All the patients received intravenous thrombolysis (70% received alteplase, and 30% received tenecteplase), and 225 patients (44%) underwent endovascular thrombectomy. At 90 days, the mean (±SD) utility-weighted modified Rankin scale scores were 5.2±3.7 with argatroban, 6.3±3.2 with eptifibatide, and 6.8±3.0 with placebo. The posterior probability that argatroban was better than placebo was 0.002 (posterior mean difference in utility-weighted modified Rankin scale score, -1.51±0.51) and that eptifibatide was better than placebo was 0.041 (posterior mean difference, -0.50±0.29). The incidence of symptomatic intracranial hemorrhage was similar in the three groups (4% with argatroban, 3% with eptifibatide, and 2% with placebo). Mortality at 90 days was higher in the argatroban group (24%) and the eptifibatide group (12%) than in the placebo group (8%). CONCLUSIONS: In patients with acute ischemic stroke treated with intravenous thrombolysis within 3 hours after symptom onset, adjunctive treatment with intravenous argatroban or eptifibatide did not reduce poststroke disability and was associated with increased mortality. (Funded by the National Institute of Neurological Disorders and Stroke; MOST ClinicalTrials.gov number, NCT03735979.).

TFAP2 paralogs regulate midfacial development in part through a conserved ALX genetic pathway.

Cranial neural crest development is governed by positional gene regulatory networks (GRNs). Fine-tuning of the GRN components underlies facial shape variation, yet how those networks in the midface are connected and activated remain poorly understood. Here, we show that concerted inactivation of Tfap2a and Tfap2b in the murine neural crest, even during the late migratory phase, results in a midfacial cleft and skeletal abnormalities. Bulk and single-cell RNA-seq profiling reveal that loss of both TFAP2 family members dysregulates numerous midface GRN components involved in midface morphogenesis, patterning and differentiation. Notably, Alx1, Alx3 and Alx4 (ALX) transcript levels are reduced, whereas ChIP-seq analyses suggest TFAP2 family members directly and positively regulate ALX gene expression. Tfap2a, Tfap2b and ALX co-expression in midfacial neural crest cells of both mouse and zebrafish implies conservation of this regulatory axis across vertebrates. Consistent with this notion, tfap2a zebrafish mutants present with abnormal alx3 expression patterns, Tfap2a binds ALX loci and tfap2a-alx3 genetic interactions are observed. Together, these data demonstrate TFAP2 paralogs regulate vertebrate midfacial development in part by activating expression of ALX transcription factor genes.

Developmental and biophysical determinants of grass leaf size worldwide.

One of the most notable ecological trends-described more than 2,300  years ago by Theophrastus-is the association of small leaves with dry and cold climates, which has recently been recognized for eudicotyledonous plants at a global scale1-3. For eudicotyledons, this pattern has been attributed to the fact that small leaves have a thinner boundary layer that helps to avoid extreme leaf temperatures4 and their leaf development results in vein traits that improve water transport under cold or dry climates5,6. However, the global distribution of leaf size and its adaptive basis have not been tested in the grasses, which represent a diverse lineage that is distinct in leaf morphology and that contributes 33% of terrestrial primary productivity (including the bulk of crop production)7. Here we demonstrate that grasses have shorter and narrower leaves under colder and drier climates worldwide. We show that small grass leaves have thermal advantages and vein development that contrast with those of eudicotyledons, but that also explain the abundance of small leaves in cold and dry climates. The worldwide distribution of leaf size in grasses exemplifies how biophysical and developmental processes result in convergence across major lineages in adaptation to climate globally, and highlights the importance of leaf size and venation architecture for grass performance in past, present and future ecosystems.

CO2 Electrolyzers.

CO2 electrolyzers have progressed rapidly in energy efficiency and catalyst selectivity toward valuable chemical feedstocks and fuels, such as syngas, ethylene, ethanol, and methane. However, each component within these complex systems influences the overall performance, and the further advances needed to realize commercialization will require an approach that considers the whole process, with the electrochemical cell at the center. Beyond the cell boundaries, the electrolyzer must integrate with upstream CO2 feeds and downstream separation processes in a way that minimizes overall product energy intensity and presents viable use cases. Here we begin by describing upstream CO2 sources, their energy intensities, and impurities. We then focus on the cell, the most common CO2 electrolyzer system architectures, and each component within these systems. We evaluate the energy savings and the feasibility of alternative approaches including integration with CO2 capture, direct conversion of flue gas and two-step conversion via carbon monoxide. We evaluate pathways that minimize downstream separations and produce concentrated streams compatible with existing sectors. Applying this comprehensive upstream-to-downstream approach, we highlight the most promising routes, and outlook, for electrochemical CO2 reduction.

Molecular tuning of CO2-to-ethylene conversion.

The electrocatalytic reduction of carbon dioxide, powered by renewable electricity, to produce valuable fuels and feedstocks provides a sustainable and carbon-neutral approach to the storage of energy produced by intermittent renewable sources1. However, the highly selective generation of economically desirable products such as ethylene from the carbon dioxide reduction reaction (CO2RR) remains a challenge2. Tuning the stabilities of intermediates to favour a desired reaction pathway can improve selectivity3-5, and this has recently been explored for the reaction on copper by controlling morphology6, grain boundaries7, facets8, oxidation state9 and dopants10. Unfortunately, the Faradaic efficiency for ethylene is still low in neutral media (60 per cent at a partial current density of 7 milliamperes per square centimetre in the best catalyst reported so far9), resulting in a low energy efficiency. Here we present a molecular tuning strategy-the functionalization of the surface of electrocatalysts with organic molecules-that stabilizes intermediates for more selective CO2RR to ethylene. Using electrochemical, operando/in situ spectroscopic and computational studies, we investigate the influence of a library of molecules, derived by electro-dimerization of arylpyridiniums11, adsorbed on copper. We find that the adhered molecules improve the stabilization of an 'atop-bound' CO intermediate (that is, an intermediate bound to a single copper atom), thereby favouring further reduction to ethylene. As a result of this strategy, we report the CO2RR to ethylene with a Faradaic efficiency of 72 per cent at a partial current density of 230 milliamperes per square centimetre in a liquid-electrolyte flow cell in a neutral medium. We report stable ethylene electrosynthesis for 190 hours in a system based on a membrane-electrode assembly that provides a full-cell energy efficiency of 20 per cent. We anticipate that this may be generalized to enable molecular strategies to complement heterogeneous catalysts by stabilizing intermediates through local molecular tuning.

CpG dinucleotide enrichment in the influenza A virus genome as a live attenuated vaccine development strategy.

Synonymous recoding of RNA virus genomes is a promising approach for generating attenuated viruses to use as vaccines. Problematically, recoding typically hinders virus growth, but this may be rectified using CpG dinucleotide enrichment. CpGs are recognised by cellular zinc-finger antiviral protein (ZAP), and so in principle, removing ZAP sensing from a virus propagation system will reverse attenuation of a CpG-enriched virus, enabling high titre yield of a vaccine virus. We tested this using a vaccine strain of influenza A virus (IAV) engineered for increased CpG content in genome segment 1. Virus attenuation was mediated by the short isoform of ZAP, correlated with the number of CpGs added, and was enacted via turnover of viral transcripts. The CpG-enriched virus was strongly attenuated in mice, yet conveyed protection from a potentially lethal challenge dose of wildtype virus. Importantly for vaccine development, CpG-enriched viruses were genetically stable during serial passage. Unexpectedly, in both MDCK cells and embryonated hens' eggs that are used to propagate live attenuated influenza vaccines, the ZAP-sensitive virus was fully replication competent. Thus, ZAP-sensitive CpG enriched viruses that are defective in human systems can yield high titre in vaccine propagation systems, providing a realistic, economically viable platform to augment existing live attenuated vaccines.

Climate change and overfishing increase neurotoxicant in marine predators.

More than three billion people rely on seafood for nutrition. However, fish are the predominant source of human exposure to methylmercury (MeHg), a potent neurotoxic substance. In the United States, 82% of population-wide exposure to MeHg is from the consumption of marine seafood and almost 40% is from fresh and canned tuna alone1. Around 80% of the inorganic mercury (Hg) that is emitted to the atmosphere from natural and human sources is deposited in the ocean2, where some is converted by microorganisms to MeHg. In predatory fish, environmental MeHg concentrations are amplified by a million times or more. Human exposure to MeHg has been associated with long-term neurocognitive deficits in children that persist into adulthood, with global costs to society that exceed US$20 billion3. The first global treaty on reductions in anthropogenic Hg emissions (the Minamata Convention on Mercury) entered into force in 2017. However, effects of ongoing changes in marine ecosystems on bioaccumulation of MeHg in marine predators that are frequently consumed by humans (for example, tuna, cod and swordfish) have not been considered when setting global policy targets. Here we use more than 30 years of data and ecosystem modelling to show that MeHg concentrations in Atlantic cod (Gadus morhua) increased by up to 23% between the 1970s and 2000s as a result of dietary shifts initiated by overfishing. Our model also predicts an estimated 56% increase in tissue MeHg concentrations in Atlantic bluefin tuna (Thunnus thynnus) due to increases in seawater temperature between a low point in 1969 and recent peak levels-which is consistent with 2017 observations. This estimated increase in tissue MeHg exceeds the modelled 22% reduction that was achieved in the late 1990s and 2000s as a result of decreased seawater MeHg concentrations. The recently reported plateau in global anthropogenic Hg emissions4 suggests that ocean warming and fisheries management programmes will be major drivers of future MeHg concentrations in marine predators.

Stimuli-responsive vesicles as distributed artificial organelles for bacterial activation.

Intercellular communication is a hallmark of living systems. As such, engineering artificial cells that possess this behavior has been at the heart of activities in bottom-up synthetic biology. Communication between artificial and living cells has potential to confer novel capabilities to living organisms that could be exploited in biomedicine and biotechnology. However, most current approaches rely on the exchange of chemical signals that cannot be externally controlled. Here, we report two types of remote-controlled vesicle-based artificial organelles that translate physical inputs into chemical messages that lead to bacterial activation. Upon light or temperature stimulation, artificial cell membranes are activated, releasing signaling molecules that induce protein expression in Escherichia coli. This distributed approach differs from established methods for engineering stimuli-responsive bacteria. Here, artificial cells (as opposed to bacterial cells themselves) are the design unit. Having stimuli-responsive elements compartmentalized in artificial cells has potential applications in therapeutics, tissue engineering, and bioremediation. It will underpin the design of hybrid living/nonliving systems where temporal control over population interactions can be exerted.

Multidecadal declines in particulate mercury and sediment export from Russian rivers in the pan-Arctic basin.

SignificanceRussian rivers are the predominant source of riverine mercury to the Arctic Ocean, where methylmercury biomagnifies to high levels in food webs. Pollution controls are thought to have decreased late-20th-century mercury loading to Arctic watersheds, but there are no published long-term observations on mercury in Russian rivers. Here, we present a unique hydrochemistry dataset to determine trends in Russian river particulate mercury concentrations and fluxes in recent decades. Using hydrologic and mercury deposition modeling together with multivariate time series analysis, we determine that 70 to 90% declines in particulate mercury fluxes were driven by pollution reductions and sedimentation in reservoirs. Results suggest that Russian rivers likely dominated over all other sources of mercury to the Arctic Ocean until recently.

Emergent Large Vessel Occlusion due to Intracranial Stenosis: Identification, Management, Challenges, and Future Directions.

This comprehensive literature review focuses on acute stroke related to intracranial atherosclerotic stenosis (ICAS), with an emphasis on ICAS-large vessel occlusion. ICAS is the leading cause of stroke globally, with high recurrence risk, especially in Asian, Black, and Hispanic populations. Various risk factors, including hypertension, diabetes, hyperlipidemia, smoking, and advanced age lead to ICAS, which in turn results in stroke through different mechanisms. Recurrent stroke risk in patients with ICAS with hemodynamic failure is particularly high, even with aggressive medical management. Developments in advanced imaging have improved our understanding of ICAS and ability to identify high-risk patients who could benefit from intervention. Herein, we focus on current management strategies for ICAS-large vessel occlusion discussed, including the use of perfusion imaging, endovascular therapy, and stenting. In addition, we focus on strategies that aim at identifying subjects at higher risk for early recurrent risk who could benefit from early endovascular intervention The review underscores the need for further research to optimize ICAS-large vessel occlusion treatment strategies, a traditionally understudied topic.

Hemodynamic Stroke: Emerging Concepts, Risk Estimation, and Treatment.

Ischemic stroke can arise from the sudden occlusion of a brain-feeding artery by a clot (embolic), or local thrombosis. Hemodynamic stroke occurs when blood flow does not sufficiently meet the metabolic demand of a brain region at a certain time. This discrepancy between demand and supply can occur with cerebropetal arterial occlusion or high-grade stenosis but also arises with systemic conditions reducing blood pressure. Treatment of hemodynamic stroke is targeted toward increasing blood flow to the affected area by either systemically or locally enhancing perfusion. Thus, blood pressure is often maintained above normal values, and extra-intracranial flow augmentation bypass surgery is increasingly considered. Still, current evidence supporting the superiority of pressure or flow increase over conservative measures is limited. However, methods assessing hemodynamic impairment and identifying patients at risk of hemodynamic stroke are rapidly evolving. Sophisticated models incorporating clinical and imaging factors have been suggested to aid patient selection. In this narrative review, we provide current state-of-the-art knowledge about hemodynamic stroke, tools for assessment, and treatment options.

Addressing the Evidence Gap in Aneurysmal Subarachnoid Hemorrhage: The Need for a Pragmatic Randomized Trial Platform.

Aneurysmal subarachnoid hemorrhage (aSAH) occurs less often than other stroke types but affects younger patients, imposing a disproportionately high burden of long-term disability. Although management advances have improved outcomes over time, relatively few aSAH treatments have been tested in randomized clinical trials (RCTs). One lesson learned from COVID-19 is that trial platforms can facilitate the efficient execution of multicenter RCTs even in complex diseases during challenging conditions. An aSAH trial platform with standardized eligibility criteria, randomization procedures, and end point definitions would enable the study of multiple targeted interventions in a perpetual manner, with treatments entering and leaving the platform based on predefined decision algorithms. An umbrella institutional review board protocol and clinical trial agreement would allow individual arms to be efficiently added as amendments rather than stand-alone protocols. Standardized case report forms using the National Institutes of Health/National Institute of Neurological Disorders and Stroke common data elements and general protocol standardization across arms would create synergies for data management and monitoring. A Bayesian analysis framework would emphasize frequent interim looks to enable early termination of trial arms for futility, common controls, borrowing of information across arms, and adaptive designs. A protocol development committee would assist investigators and encourage pragmatic designs to maximize generalizability, reduce site burden, and execute trials efficiently and cost-effectively. Despite decades of steady clinical progress in the management of aSAH, poor patient outcomes remain common, and despite the increasing availability of RCT data in other fields, it remains difficult to perform RCTs to guide more effective care for aSAH. The development of a platform for pragmatic RCTs in aSAH would help close the evidence gap between aSAH and other stroke types and improve outcomes for this important disease with its disproportionate public health burden.

Transcarotid Arterial Revascularization of Symptomatic Internal Carotid Artery Disease: A Systematic Review and Study-Level Meta-Analysis.

BACKGROUND: Transcarotid artery revascularization (TCAR) is an interventional therapy for symptomatic internal carotid artery disease. Currently, the utilization of TCAR is contentious due to limited evidence. In this study, we evaluate the safety and efficacy of TCAR in patients with symptomatic internal carotid artery disease compared with carotid endarterectomy (CEA) and carotid artery stenting (CAS). METHODS: A systematic review was conducted, spanning from January 2000 to February 2023, encompassing studies that used TCAR for the treatment of symptomatic internal carotid artery disease. The primary outcomes included a 30-day stroke or transient ischemic attack, myocardial infarction, and mortality. Secondary outcomes comprised cranial nerve injury and major bleeding. Pooled odds ratios (ORs) for each outcome were calculated to compare TCAR with CEA and CAS. Furthermore, subgroup analyses were performed based on age and degree of stenosis. In addition, a sensitivity analysis was conducted by excluding the vascular quality initiative registry population. RESULTS: A total of 7 studies involving 24 246 patients were analyzed. Within this patient cohort, 4771 individuals underwent TCAR, 12 350 underwent CEA, and 7125 patients underwent CAS. Compared with CAS, TCAR was associated with a similar rate of stroke or transient ischemic attack (OR, 0.77 [95% CI, 0.33-1.82]) and myocardial infarction (OR, 1.29 [95% CI, 0.83-2.01]) but lower mortality (OR, 0.42 [95% CI, 0.22-0.81]). Compared with CEA, TCAR was associated with a higher rate of stroke or transient ischemic attack (OR, 1.26 [95% CI, 1.03-1.54]) but similar rates of myocardial infarction (OR, 0.9 [95% CI, 0.64-1.38]) and mortality (OR, 1.35 [95% CI, 0.87-2.10]). CONCLUSIONS: Although CEA has traditionally been considered superior to stenting for symptomatic carotid stenosis, TCAR may have some advantages over CAS. Prospective randomized trials comparing the 3 modalities are needed.

Unspoken Truths: Mental Health Among Academic Surgeons.

OBJECTIVE: To characterize the current state of mental health within the surgical workforce in the United States. BACKGROUND: Mental illness and suicide is a growing concern in the medical community; however, the current state is largely unknown. METHODS: Cross-sectional survey of the academic surgery community assessing mental health, medical error, and suicidal ideation. The odds of suicidal ideation adjusting for sex, prior mental health diagnosis, and validated scales screening for depression, anxiety, post-traumatic stress disorder (PTSD), and alcohol use disorder were assessed. RESULTS: Of 622 participating medical students, trainees, and surgeons (estimated response rate=11.4%-14.0%), 26.1% (141/539) reported a previous mental health diagnosis. In all, 15.9% (83/523) of respondents screened positive for current depression, 18.4% (98/533) for anxiety, 11.0% (56/510) for alcohol use disorder, and 17.3% (36/208) for PTSD. Medical error was associated with depression (30.7% vs. 13.3%, P <0.001), anxiety (31.6% vs. 16.2%, P =0.001), PTSD (12.8% vs. 5.6%, P =0.018), and hazardous alcohol consumption (18.7% vs. 9.7%, P =0.022). Overall, 13.2% (73/551) of respondents reported suicidal ideation in the past year and 9.6% (51/533) in the past 2 weeks. On adjusted analysis, a previous history of a mental health disorder (aOR: 1.97, 95% CI: 1.04-3.65, P =0.033) and screening positive for depression (aOR: 4.30, 95% CI: 2.21-8.29, P <0.001) or PTSD (aOR: 3.93, 95% CI: 1.61-9.44, P =0.002) were associated with increased odds of suicidal ideation over the past 12 months. CONCLUSIONS: Nearly 1 in 7 respondents reported suicidal ideation in the past year. Mental illness and suicidal ideation are significant problems among the surgical workforce in the United States.

Utilizing connectome fingerprinting functional MRI models for motor activity prediction in presurgical planning: A feasibility study.

Presurgical planning prior to brain tumor resection is critical for the preservation of neurologic function post-operatively. Neurosurgeons increasingly use advanced brain mapping techniques pre- and intra-operatively to delineate brain regions which are "eloquent" and should be spared during resection. Functional MRI (fMRI) has emerged as a commonly used non-invasive modality for individual patient mapping of critical cortical regions such as motor, language, and visual cortices. To map motor function, patients are scanned using fMRI while they perform various motor tasks to identify brain networks critical for motor performance, but it may be difficult for some patients to perform tasks in the scanner due to pre-existing deficits. Connectome fingerprinting (CF) is a machine-learning approach that learns associations between resting-state functional networks of a brain region and the activations in the region for specific tasks; once a CF model is constructed, individualized predictions of task activation can be generated from resting-state data. Here we utilized CF to train models on high-quality data from 208 subjects in the Human Connectome Project (HCP) and used this to predict task activations in our cohort of healthy control subjects (n = 15) and presurgical patients (n = 16) using resting-state fMRI (rs-fMRI) data. The prediction quality was validated with task fMRI data in the healthy controls and patients. We found that the task predictions for motor areas are on par with actual task activations in most healthy subjects (model accuracy around 90%-100% of task stability) and some patients suggesting the CF models can be reliably substituted where task data is either not possible to collect or hard for subjects to perform. We were also able to make robust predictions in cases in which there were no task-related activations elicited. The findings demonstrate the utility of the CF approach for predicting activations in out-of-sample subjects, across sites and scanners, and in patient populations. This work supports the feasibility of the application of CF models to presurgical planning, while also revealing challenges to be addressed in future developments. PRACTITIONER POINTS: Precision motor network prediction using connectome fingerprinting. Carefully trained models' performance limited by stability of task-fMRI data. Successful cross-scanner predictions and motor network mapping in patients with tumor.

Metal content and kinetic properties of yeast RNA lariat debranching enzyme Dbr1.

In eukaryotic cells, intron lariats produced by the spliceosome contain a 2'5' phosphodiester linkage. The RNA lariat debranching enzyme, Dbr1, is the only enzyme known to hydrolyze this bond. Dbr1 is a member of the metallophosphoesterase (MPE) family of enzymes, and recent X-ray crystal structures and biochemistry data demonstrate that Dbr1 from Entamoeba histolytica uses combinations of Mn2+, Zn2+, and Fe2+ as enzymatic cofactors. Here, we examine the kinetic properties and metal dependence of the Dbr1 homolog from Saccharomyces cerevisiae (yDbr1). Elemental analysis measured stoichiometric quantities of Fe and Zn in yDbr1 purified following heterologous expression E. coli We analyzed the ability of Fe2+, Zn2+, and Mn2+ to reconstitute activity in metal-free apoenzyme. Purified yDbr1 was highly active, turning over substrate at 5.6 sec-1, and apo-yDbr1 reconstituted with Fe2+ was the most active species, turning over at 9.2 sec-1 We treated human lymphoblastoid cells with the iron-chelator deferoxamine and measured a twofold increase in cellular lariats. These data suggest that Fe is an important biological cofactor for Dbr1 enzymes.

Long-Term Oncological Outcomes in Patients Diagnosed With Nonmetastatic Plasmacytoid Variant of Bladder Cancer: A 20-Year University of Texas MD Anderson Cancer Center Experience.

PURPOSE: The treated natural history of nonmetastatic plasmacytoid variant of bladder cancer (PV-BCa) is poorly understood owing to its rarity. We sought to examine the disease recurrence and metastasis patterns in this select group of patients in order to identify opportunities for intervention. MATERIALS AND METHODS: We conducted a natural language processing algorithm-augmented retrospective chart review of 56 consecutive patients who were treated with curative intent for nonmetastatic PV-BCa at our institution between 1998 and 2018. Kaplan-Meier and multivariable Cox regression methods were used for survival analyses. RESULTS: The stage at presentation was: ≤ cT2N0 in 22 (39.3%), cT3N0 in 15 (26.8%), cT4N0 in 13 (23.2%), and ≥ cN1 in 6 patients (10.7%). Forty-nine patients (87.5%) received chemotherapy, and 42 (75%) were able to undergo the planned surgery. Notably, only 4 patients (7.2%) had pT0 stage, while 22 (52.4%) had pN+ disease at the time of surgery. At 36-month follow-up, 28.4% of patients (95% CI: 22.1%-34.5%) were alive and 22.2% (95% CI: 16.1%-28.5%) were free of metastatic disease. The benefit of surgical extirpation was stage specific: successful completion of surgery was associated with improved metastasis-free survival (at 36 months 32.4% vs 0%, log-rank P < .001) in patients with localized or locally advanced disease (≤cT2N0/cT3N0); however, in patients with regionally advanced disease (cT4N0/≥cN1), consolidative surgery following chemotherapy was not associated with improved metastasis-free survival (12.5% vs 10% at 36 months, log-rank P = .49). The median time to metastasis from primary treatment end was 6.5 months (IQR: 2.9-14.7). The predominant site of recurrence/metastasis was the peritoneum (76.1%), either in isolation or along with extraperitoneal lesions. Salvage immunotherapy in these patients significantly reduced the risk of death (HR = 0.11, P = .001). CONCLUSIONS: PV-BCa is a disease with high lethality. Despite multimodal treatment, a vast majority of patients develop atypical intraperitoneal metastasis soon after therapy and rapidly succumb to it. Clinical trials evaluating utility of hyperthermic intraperitoneal chemotherapy and/or immunotherapy may be warranted in this high-risk population.