Stromal Microenvironment Shapes the Intratumoral Architecture of Pancreatic Cancer.

Single-cell technologies have described heterogeneity across tissues, but the spatial distribution and forces that drive single-cell phenotypes have not been well defined. Combining single-cell RNA and protein analytics in studying the role of stromal cancer-associated fibroblasts (CAFs) in modulating heterogeneity in pancreatic cancer (pancreatic ductal adenocarcinoma [PDAC]) model systems, we have identified significant single-cell population shifts toward invasive epithelial-to-mesenchymal transition (EMT) and proliferative (PRO) phenotypes linked with mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) signaling. Using high-content digital imaging of RNA in situ hybridization in 195 PDAC tumors, we quantified these EMT and PRO subpopulations in 319,626 individual cancer cells that can be classified within the context of distinct tumor gland "units." Tumor gland typing provided an additional layer of intratumoral heterogeneity that was associated with differences in stromal abundance and clinical outcomes. This demonstrates the impact of the stroma in shaping tumor architecture by altering inherent patterns of tumor glands in human PDAC.

Chromatin-bound RB targets promoters, enhancers, and CTCF-bound loci and is redistributed by cell-cycle progression.

The interaction of RB with chromatin is key to understanding its molecular functions. Here, for first time, we identify the full spectrum of chromatin-bound RB. Rather than exclusively binding promoters, as is often described, RB targets three fundamentally different types of loci (promoters, enhancers, and insulators), which are largely distinguishable by the mutually exclusive presence of E2F1, c-Jun, and CTCF. While E2F/DP facilitates RB association with promoters, AP-1 recruits RB to enhancers. Although phosphorylation in CDK sites is often portrayed as releasing RB from chromatin, we show that the cell cycle redistributes RB so that it enriches at promoters in G1 and at non-promoter sites in cycling cells. RB-bound promoters include the classic E2F-targets and are similar between lineages, but RB-bound enhancers associate with different categories of genes and vary between cell types. Thus, RB has a well-preserved role controlling E2F in G1, and it targets cell-type-specific enhancers and CTCF sites when cells enter S-phase.

A Code of Mono-phosphorylation Modulates the Function of RB.

Hyper-phosphorylation of RB controls its interaction with E2F and inhibits its tumor suppressor properties. However, during G1 active RB can be mono-phosphorylated on any one of 14 CDK phosphorylation sites. Here, we used quantitative proteomics to profile protein complexes formed by each mono-phosphorylated RB isoform (mP-RB) and identified the associated transcriptional outputs. The results show that the 14 sites of mono-phosphorylation co-ordinate RB's interactions and confer functional specificity. All 14 mP-RBs interact with E2F/DP proteins, but they provide different shades of E2F regulation. RB mono-phosphorylation at S811, for example, alters RB transcriptional activity by promoting its association with NuRD complexes. The greatest functional differences between mP-RBs are evident beyond the cell cycle machinery. RB mono-phosphorylation at S811 or T826 stimulates the expression of oxidative phosphorylation genes, increasing cellular oxygen consumption. These results indicate that RB activation signals are integrated in a phosphorylation code that determines the diversity of RB activity.

APOE2 gene therapy reduces amyloid deposition and improves markers of neuroinflammation and neurodegeneration in a mouse model of Alzheimer disease.

Epidemiological studies show that individuals who carry the relatively uncommon APOE ε2 allele rarely develop Alzheimer disease, and if they do, they have a later age of onset, milder clinical course, and less severe neuropathological findings than people without this allele. The contrast is especially stark when compared with the major genetic risk factor for Alzheimer disease, APOE ε4, which has an age of onset several decades earlier, a more aggressive clinical course and more severe neuropathological findings, especially in terms of the amount of amyloid deposition. Here, we demonstrate that brain exposure to APOE ε2 via a gene therapy approach, which bathes the entire cortical mantle in the gene product after transduction of the ependyma, reduces Aß plaque deposition, neurodegenerative synaptic loss, and, remarkably, reduces microglial activation in an APP/PS1 mouse model despite continued expression of human APOE ε4. This result suggests a promising protective effect of exogenous APOE ε2 and reveals a cell nonautonomous effect of the protein on microglial activation, which we show is similar to plaque-associated microglia in the brain of Alzheimer disease patients who inherit APOE ε2. These data increase the potential that an APOE ε2 therapeutic could be effective in Alzheimer disease, even in individuals born with the risky ε4 allele.

Reactivity umpolung (reversal) of ligands in transition metal complexes.

The success and power of homogeneous catalysis derives in large part from the wide choice of transition metal ions and their ligands. This tutorial review introduces examples where the reactivity of a ligand is completely reversed (umpolung) from Lewis basic/nucleophilic to acidic/electrophilic or vice versa on changing the metal and co-ligands. Understanding this phenomenon will assist in the rational design of catalysts and the understanding of metalloenzyme mechanisms. Labelling a metal and ligand with Seebach donor and acceptor labels helps to identify whether a reaction involving the intermolecular attack on the ligand is displaying native reactivity or reactivity umpolung. This has been done for complexes of nitriles, carbonyls, isonitriles, dinitrogen, Fischer carbenes, alkenes, alkynes, hydrides, methyls, methylidenes and alkylidenes, silylenes, oxides, imides/nitrenes, alkylidynes, methylidynes, and nitrides. The electronic influence of the metal and co-ligands is discussed in terms of the energy of (HOMO) d electrons. The energy can be related to the pKLACa (LAC is ligand acidity constant) of the theoretical hydride complexes [H-[M]-L]+ formed by the protonation of pair of valence d electrons on the metal in the [M-L] complex. Preliminary findings indicate that a negative pKLACa indicates that nucleophilic attack by a carbanion or amine on the ligand will likely occur while a positive pKLACa indicates that electrophilic attack by strong acids on the ligand will usually occur when the ligand is nitrile, carbonyl, isonitrile, alkene and η6-arene.

ATR inhibition disrupts rewired homologous recombination and fork protection pathways in PARP inhibitor-resistant BRCA-deficient cancer cells.

Poly-(ADP-ribose) polymerase (PARP) inhibitors (PARPis) selectively kill BRCA1/2-deficient cells, but their efficacy in BRCA-deficient patients is limited by drug resistance. Here, we used derived cell lines and cells from patients to investigate how to overcome PARPi resistance. We found that the functions of BRCA1 in homologous recombination (HR) and replication fork protection are sequentially bypassed during the acquisition of PARPi resistance. Despite the lack of BRCA1, PARPi-resistant cells regain RAD51 loading to DNA double-stranded breaks (DSBs) and stalled replication forks, enabling two distinct mechanisms of PARPi resistance. Compared with BRCA1-proficient cells, PARPi-resistant BRCA1-deficient cells are increasingly dependent on ATR for survival. ATR inhibitors (ATRis) disrupt BRCA1-independent RAD51 loading to DSBs and stalled forks in PARPi-resistant BRCA1-deficient cells, overcoming both resistance mechanisms. In tumor cells derived from patients, ATRis also overcome the bypass of BRCA1/2 in fork protection. Thus, ATR inhibition is a unique strategy to overcome the PARPi resistance of BRCA-deficient cancers.

Occult residual ovarian tissue at the time of minimally invasive risk reducing surgery in women with BRCA mutations.

OBJECTIVE: To describe extension of ovarian tissue beyond visible and National Comprehensive Cancer Network recommended margins among patients with BRCA mutations undergoing minimally invasive risk-reducing salpingo-oophorectomy. METHODS: A prospective study of patients with BRCA mutations who underwent minimally invasive risk-reducing bilateral salpingo-oophorectomy was conducted. Patient enrollment occurred between October 2021 and 2023. Tissue specimens were analyzed according to the Sectioning and Extensively Examining the Fimbriated End protocol. RESULTS: Twenty women with BRCA mutations were prospectively enrolled. All patients underwent minimally invasive surgery with 70% undergoing concurrent hysterectomy (n = 14). Approximately half of these procedures were performed with robotic assistance (n = 9, 45%). One patient was admitted overnight (5%); the other nineteen were discharged on the day of surgery (95%). One patient experienced a major complication and required readmission (5%). Extension of ovarian tissue beyond the visible ovary was noted on pathologic examination of six specimens (30%). In one patient this was observed on the left (17%), in three on the right (50%), and in two bilateral extension (33%) was noted. The distance ovarian stroma extended microscopically beyond the visible ovary was between 2 and 14 mm, with a median of 5 mm. Among patients with microscopic extension of ovarian tissue, the majority (n = 5, 83%) had a BRCA2 mutation. CONCLUSION: In women with BRCA mutations undergoing risk-reducing minimally invasive surgery, approximately one third had microscopic extension of ovarian stroma beyond the visible ovary. Current guidelines which recommend resection of at least 20 mm of tissue beyond the visible ovary are likely adequate in this population.

Current state of musculoskeletal fellowship program directors and future directions.

OBJECTIVE: To better understand the current state of musculoskeletal fellowship program directors and identify opportunities for formal training that could increase job satisfaction, provide a broader knowledge base for mentoring/advising trainees and increase diversity in musculoskeletal radiology. MATERIALS AND METHODS: Eighty-one fellowship program directors who signed the Fellowship Match Memorandum of Understanding with the Society of Skeletal Radiology were sent a survey with questions about demographics, career, background, and training both for musculoskeletal radiology and for the fellowship director role. RESULTS: A 57/81 (70%) of program directors responded, representing 27 different states with a range of 1-9 fellowship positions. Nearly half are in their forties (48%) with most identifying as White (67%) followed by Asian (30%). The majority are male (72%) with over half (60%) remaining at the institution where they completed prior training. Over half plan to change roles within 5 years and do not feel adequately compensated. Top qualities/skills identified as important for the role include effective communication, being approachable, and clinical excellence. Other than clinical excellence, most do not report formal training in skills identified as important for the role. CONCLUSIONS: Given the high amount of interaction with trainees, program directors play a key role in the future of our subspecialty. The low diversity among this group, the lack of formal training, and the fact that most do not feel adequately compensated could limit mentorship and recruitment. Program directors identified effective communication, organizational/planning skills, and conflict resolution as the top skills they would benefit from formal training.

Mental Wellness Self-Care in Singapore With mindline.sg: A Tutorial on the Development of a Digital Mental Health Platform for Behavior Change.

BACKGROUND: Singapore, like the rest of Asia, faces persistent challenges to mental health promotion, including stigma around unwellness and seeking treatment and a lack of trained mental health personnel. The COVID-19 pandemic, which created a surge in mental health care needs and simultaneously accelerated the adoption of digital health solutions, revealed a new opportunity to quickly scale innovative solutions in the region. OBJECTIVE: In June 2020, the Singaporean government launched mindline.sg, an anonymous digital mental health resource website that has grown to include >500 curated local mental health resources, a clinically validated self-assessment tool for depression and anxiety, an artificial intelligence (AI) chatbot from Wysa designed to deliver digital therapeutic exercises, and a tailored version of the website for working adults called mindline at work. The goal of the platform is to empower Singapore residents to take charge of their own mental health and to be able to offer basic support to those around them through the ease and convenience of a barrier-free digital solution. METHODS: Website use is measured through click-level data analytics captured via Google Analytics and custom application programming interfaces, which in turn drive a customized analytics infrastructure based on the open-source platforms Titanium Database and Metabase. Unique, nonbounced (users that do not immediately navigate away from the site), engaged, and return users are reported. RESULTS: In the 2 years following launch (July 1, 2020, through June 30, 2022), the website received >447,000 visitors (approximately 15% of the target population of 3 million), 62.02% (277,727/447,783) of whom explored the site or engaged with resources (referred to as nonbounced visitors); 10.54% (29,271/277,727) of those nonbounced visitors returned. The most popular features on the platform were the dialogue-based therapeutic exercises delivered by the chatbot and the self-assessment tool, which were used by 25.54% (67,626/264,758) and 11.69% (32,469/277,727) of nonbounced visitors. On mindline at work, the rates of nonbounced visitors who engaged extensively (ie, spent ≥40 seconds exploring resources) and who returned were 51.56% (22,474/43,588) and 13.43% (5,853/43,588) over a year, respectively, compared to 30.9% (42,829/138,626) and 9.97% (13,822/138,626), respectively, on the generic mindline.sg site in the same year. CONCLUSIONS: The site has achieved desired reach and has seen a strong growth rate in the number of visitors, which required substantial and sustained digital marketing campaigns and strategic outreach partnerships. The site was careful to preserve anonymity, limiting the detail of analytics. The good levels of overall adoption encourage us to believe that mild to moderate mental health conditions and the social factors that underly them are amenable to digital interventions. While mindline.sg was primarily used in Singapore, we believe that similar solutions with local customization are widely and globally applicable.

A lower bound for set-coloring Ramsey numbers.

The set-coloring Ramsey number Rr,s(k) is defined to be the minimum n such that if each edge of the complete graph Kn is assigned a set of s colors from {1,…,r}, then one of the colors contains a monochromatic clique of size k. The case s=1 is the usual r-color Ramsey number, and the case s=r-1 was studied by Erdos, Hajnal and Rado in 1965, and by Erdos and Szemerédi in 1972. The first significant results for general s were obtained only recently, by Conlon, Fox, He, Mubayi, Suk and Verstraëte, who showed that Rr,s(k)=2Θ(kr) if s/r is bounded away from 0 and 1. In the range s=r-o(r), however, their upper and lower bounds diverge significantly. In this note we introduce a new (random) coloring, and use it to determine Rr,s(k) up to polylogarithmic factors in the exponent for essentially all r, s, and k.

Monomeric myeloperoxidase is a specific biomarker for early-stage ovarian cancer.

Background: Ovarian cancer cells are known to express myeloperoxidase (MPO), an oxidant-producing enzyme with a 150 kDa homodimer, consisting of two identical monomers connected by a disulfide bond. Here, we aim to validate monomeric MPO (mMPO) as a biomarker for the early detection of ovarian cancer.Methods: Human ovarian cancer cells, sera from patients at various stages, sera from non-cancer inflammatory gynecological diseases, and healthy volunteers were used. Monomeric and dimeric MPO were measured by ELISA. Receiver operating curves were used to compare the predictive powers of serum dimeric and monomeric MPO to discriminate between samples.Results: The expression of MPO was unique to ovarian cancer cells. Specifically, mMPO was found to be the only form of MPO in all ovarian cancer cell lines. Intriguingly, mMPO was detected in the sera from all patients with ovarian cancer at various stages, but not from healthy individuals. Serum mMPO discriminated between early-stage ovarian cancer, healthy controls, and benign inflammatory gynecologic disorders. In addition, mMPO discriminated between the early and late stages of the disease.Conclusion: This work highlights mMPO as a potential biomarker for early detection of ovarian cancer, which is critically needed.

The Genomic Landscape of Vulvar Squamous Cell Carcinoma.

Vulvar squamous cell cancer (VSC) accounts for 90% of vulvar cancers. Next-generation sequencing studies of VSC imply human papillomavirus (HPV) and p53 status play separate roles in carcinogenesis and prognosis. We sought to describe the genomic landscape and analyze the immunologic profiles of VSC with respect to HPV and p53 status. A total of 443 VSC tumors underwent tumor profiling. Next-generation sequencing was performed on genomic DNA isolated from formalin-fixed paraffin-embedded tumor samples. PD-L1, microsatellite instability were tested by fragment analysis, IHC, and next-generation sequencing. Tumor mutational burden-high was defined as >10 mutations per MB. HPV 16/18 positive (HPV+) status was determined using whole exome sequencing on 105 samples. Three cohorts were identified from 105 samples with known HPV: HPV+, HPV-/p53wt, and HPV-/p53mt. Where HPV and p53 status were examined, TP53 mutations were exclusive of HPV+ tumors. In all, 37% of samples were HPV+. Among the 66 HPV- tumors, 52 (78.8%) were HPV-/p53mt and 14 (21.2%) were HPV-/p53wt. The HPV-/p53wt cohort had a higher rate of mutations in the PI3KCA gene (42.9% HPV-/p53wt vs 26.3% HPV+ vs. 5.8% HPV-/p53mt, q =0.028) and alterations in the PI3K/AkT/mTOR pathway (57.1% HPV-/p53wt vs. 34.2% HPV+ vs. 7.7% HPV-/p53mt, q =0.0386) than the other 2 cohorts. Ninety-eight VSC tumors with HPV16/18 information underwent transcriptomic analysis and immune deconvolution method. No differences were observed in immune profiles. The HPV-/p53wt VSC tumors had significantly higher rates of mutations in the PI3KCA gene and alterations in the PI3K/AkT/mTOR pathway, a potential target that merits further investigation in this subgroup.

Trans Ligand Determines the Stability of Paramagnetic Manganese(II) Hydrides of the Type trans-[MnH(L)(dmpe)2]+ Where L is PMe3, C2H4, or CO.

Paramagnetic metal hydride (PMH) complexes play important roles in catalytic applications and bioinorganic chemistry. 3d PMH chemistry has largely focused on Ti, Mn, Fe, and Co. Various MnII PMHs have been proposed as intermediates in catalysis, but isolated MnII PMHs are limited to dimeric high-spin MnII structures with bridging hydrides. In this paper, a series of the first low-spin monomeric MnII PMH complexes are generated by chemical oxidation of their MnI analogues. This series is of the type trans-[MnH(L)(dmpe)2]+/0 where the trans ligand L is PMe3, C2H4, or CO [dmpe is 1,2-bis(dimethylphosphino)ethane], and the thermal stability of the MnII hydride complexes was found to be strongly dependent on the identity of the trans ligand. When L is PMe3, the complex is the first example of an isolated monomeric MnII hydride complex. In contrast, when L is C2H4 or CO, the complexes are only stable at low temperatures; upon warming to room temperature, the former decomposed to afford [Mn(dmpe)3]+, accompanied by ethane and ethylene, whereas the latter eliminated H2, generating [Mn(MeCN)(CO)(dmpe)2]+ or a mixture of products including [Mn(κ1-PF6)(CO)(dmpe)2], depending on the reaction conditions. All PMHs were characterized by low-temperature electron paramagnetic resonance (EPR) spectroscopy, and stable [MnH(PMe3)(dmpe)2]+ was further characterized by UV-vis and IR spectroscopy, Superconducting Quantum Interference Device magnetometry, and single-crystal X-ray diffraction. Noteworthy spectral properties are the significant EPR superhyperfine coupling to the hydride (∼85 MHz) and an increase (+33 cm-1) in the Mn-H IR stretch upon oxidation. Density functional theory calculations were also employed to gain insights into the acidity and bond strengths of the complexes. MnII-H bond dissociation free energies are estimated to decrease in the series of complexes from 60 (L = PMe3) to 47 kcal/mol (L = CO).

A phase III, multicenter, randomized study of olvimulogene nanivacirepvec followed by platinum-doublet chemotherapy and bevacizumab compared with platinum-doublet chemotherapy and bevacizumab in women with platinum-resistant/refractory ovarian cancer.

BACKGROUND: Treatment options for patients with platinum-resistant/refractory ovarian cancers are limited and only marginally effective. The development of novel, more effective therapies addresses a critical unmet medical need. Olvimulogene nanivacirepvec (Olvi-Vec), with its strong immune modulating effect on the tumor microenvironment, may provide re-sensitization to platinum and clinically reverse platinum resistance or refractoriness in platinum-resistant/refractory ovarian cancer. PRIMARY OBJECTIVE: The primary objective is to evaluate the efficacy of intra-peritoneal Olvi-Vec followed by platinum-based chemotherapy and bevacizumab in patients with platinum-resistant/refractory ovarian cancer. STUDY HYPOTHESIS: This phase III study investigates Olvi-Vec oncolytic immunotherapy followed by platinum-based chemotherapy and bevacizumab as an immunochemotherapy evaluating the hypothesis that such sequential combination therapy will prolong progression-free survival (PFS) and bring other clinical benefits compared with treatment with platinum-based chemotherapy and bevacizumab. TRIAL DESIGN: This is a multicenter, prospective, randomized, and active-controlled phase III trial. Patients will be randomized 2:1 into the experimental arm treated with Olvi-Vec followed by platinum-doublet chemotherapy and bevacizumab or the control arm treated with platinum-doublet chemotherapy and bevacizumab. MAJOR INCLUSION/EXCLUSION CRITERIA: Eligible patients must have recurrent, platinum-resistant/refractory, non-resectable high-grade serous, endometrioid, or clear-cell ovarian, fallopian tube, or primary peritoneal cancer. Patients must have had ≥3 lines of prior chemotherapy. PRIMARY ENDPOINT: The primary endpoint is PFS in the intention-to-treat population. SAMPLE SIZE: Approximately 186 patients (approximately 124 patients randomized to the experimental arm and 62 to the control arm) will be enrolled to capture 127 PFS events. ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS: Expected complete accrual in 2024 with presentation of primary endpoint results in 2025. TRIAL REGISTRATION: NCT05281471.

Proteomic analysis of pRb loss highlights a signature of decreased mitochondrial oxidative phosphorylation.

The retinoblastoma tumor suppressor (pRb) protein associates with chromatin and regulates gene expression. Numerous studies have identified Rb-dependent RNA signatures, but the proteomic effects of Rb loss are largely unexplored. We acutely ablated Rb in adult mice and conducted a quantitative analysis of RNA and proteomic changes in the colon and lungs, where Rb(KO) was sufficient or insufficient to induce ectopic proliferation, respectively. As expected, Rb(KO) caused similar increases in classic pRb/E2F-regulated transcripts in both tissues, but, unexpectedly, their protein products increased only in the colon, consistent with its increased proliferative index. Thus, these protein changes induced by Rb loss are coupled with proliferation but uncoupled from transcription. The proteomic changes in common between Rb(KO) tissues showed a striking decrease in proteins with mitochondrial functions. Accordingly, RB1 inactivation in human cells decreased both mitochondrial mass and oxidative phosphorylation (OXPHOS) function. RB(KO) cells showed decreased mitochondrial respiratory capacity and the accumulation of hypopolarized mitochondria. Additionally, RB/Rb loss altered mitochondrial pyruvate oxidation from (13)C-glucose through the TCA cycle in mouse tissues and cultured cells. Consequently, RB(KO) cells have an enhanced sensitivity to mitochondrial stress conditions. In summary, proteomic analyses provide a new perspective on Rb/RB1 mutation, highlighting the importance of pRb for mitochondrial function and suggesting vulnerabilities for treatment.

Molecular profiles of endometrial cancer tumors among Black patients.

OBJECTIVES: Disparate outcomes exist between Black and White patients with endometrial cancer (EC). One contributing factor is the disproportionately low representation of Black patients in clinical trials and in tumor molecular profiling studies. Our objective was to investigate molecular profiles of ECs in a cohort with a high proportion of tumors from Black patients. METHODS: A total of 248 EC samples and self-reported race data were collected from 6 institutions. Comprehensive tumor profiling and analyses were performed by Caris Life Sciences. RESULTS: Tumors from 105 (42%) Black and 143 (58%) White patients were included. Serous histology (58% vs 36%) and carcinosarcoma (25% vs 16%), was more common among Black patients, and endometrioid was less common (17% vs 48%) (p < 0.01). Differences in gene mutations between cohorts corresponded to observed histologic differences between races. Specifically, TP53 mutations were predominant in serous tumors. In endometrioid tumors, mutations in ARID1A were the most common, and high rates of MSI-H, MMRd, and TMB-H were observed. In carcinosarcoma tumors, hormone receptor expression was high in tumors of Black patients (PR 23.4%, ER 30.8%). When stratified by histology, there were no significant differences between tumors from Black and White women. CONCLUSIONS: This cohort had a high proportion of tumors from Black women. Distinct molecular profiles were driven primarily by more aggressive histologic subtypes among Black women. Continued effort is needed to include Black women and other populations under-represented in EC molecular profiling studies as targeted therapies and personalized medicine become mainstream.

Correction and calibration of atmospheric impact observations in GOES GLM data.

The Earth's atmosphere is impacted daily by both meteoroids and artificial objects. Calibrated observations of the emitted light at sufficiently high sampling rates can enable or improve the estimation of impactor attributes such as size, cohesion, trajectory, and composition, but are difficult to obtain owing to the unpredictability, brevity, and high dynamic (brightness) range of impacts. Ground-based camera systems have successfully monitored small regions of the atmosphere at video frame rates and with limited radiometric capabilities, but most impacts occur over the 70% of the Earth's surface covered by water and are therefore missed by these networks. The Geostationary Lightning Mapper (GLM) instruments aboard Geostationary Operational Environmental Satellites 16 and 17 provide near-hemispherical coverage at 500 frames per second. These data have been shown to contain the signatures of many independently confirmed impacts, often from both viewing angles simultaneously, and constitute an observational resource that is currently unparalleled in the public domain. NASA's Asteroid Threat Assessment Project has implemented an automated impact detection pipeline that processes data from GLM daily. Given a detected impact, the GLM data contain a wealth of information for use in quantitative follow-up analyses. However, impact events differ from lightning in ways that violate key assumptions built into GLM's design. The result is that GLM's onboard processing introduces errors into pixel observations of impact events and the calibrated energies near the periphery of the detector may be substantially overestimated. We present methods for mitigating these and other issues to produce a data product more suitable for impact analyses than the existing GLM lightning product.

Epithelial to mesenchymal plasticity and differential response to therapies in pancreatic ductal adenocarcinoma.

Transcriptional profiling has defined pancreatic ductal adenocarcinoma (PDAC) into distinct subtypes with the majority being classical epithelial (E) or quasi-mesenchymal (QM). Despite clear differences in clinical behavior, growing evidence indicates these subtypes exist on a continuum with features of both subtypes present and suggestive of interconverting cell states. Here, we investigated the impact of different therapies being evaluated in PDAC on the phenotypic spectrum of the E/QM state. We demonstrate using RNA-sequencing and RNA-in situ hybridization (RNA-ISH) that FOLFIRINOX combination chemotherapy induces a common shift of both E and QM PDAC toward a more QM state in cell lines and patient tumors. In contrast, Vitamin D, another drug under clinical investigation in PDAC, induces distinct transcriptional responses in each PDAC subtype, with augmentation of the baseline E and QM state. Importantly, this translates to functional changes that increase metastatic propensity in QM PDAC, but decrease dissemination in E PDAC in vivo models. These data exemplify the importance of both the initial E/QM subtype and the plasticity of E/QM states in PDAC in influencing response to therapy, which highlights their relevance in guiding clinical trials.

A Plausible Mechanism for the Iridium-Catalyzed Hydrogenation of a Bulky N-Aryl Imine in the (S)-Metolachlor Process.

The hydrogenation of N-(2-ethyl-6-methylphenyl)-1-methoxypropan-2-imine is the largest-scale asymmetric catalytic process for the industrial production of agrochemical (S)-metolachlor. The challenging hydrogenation across the sterically crowded carbon-nitrogen double bond was achieved using a mixture of [IrCl(COD)]2, (R,SFc)-Xyliphos, NBu4I and acetic acid. Acetic acid was critical in achieving excellent productivity and activity. Despite its industrial significance, a mechanism that explains how the sterically hindered bond in the imine is reduced has yet to be proposed. We propose a plausible proton-first, outer-sphere mechanism based on density functional theory calculations that is consistent with the experimentally observed activity and the enantioselectivity of the industrial process. Key findings include transition states involving acetate-assisted dihydrogen splitting, and a hydride transfer from a five-coordinate iridium trihydride directed by a C-H∙∙∙Ir interaction. This article was submitted to a Special Issue in honor of Professor Henri Kagan.

Metabolic flexibility of SUP05 under low DO growth conditions.

Chemoautotrophic bacteria from the SUP05 clade often dominate anoxic waters within marine oxygen minimum zones (OMZs) where they use energy gained from the oxidation of reduced sulfur to fuel carbon fixation. Some of these SUP05 bacteria are facultative aerobes that can use either nitrate or oxygen as a terminal electron acceptor making them ideally suited to thrive at the boundaries of OMZs where they experience fluctuations in dissolved oxygen (DO). SUP05 metabolism in these regions, and therefore the biogeochemical function of SUP05, depends largely on their sensitivity to oxygen. We evaluated growth and quantified differences in gene expression in Ca. T. autotrophicus strain EF1 from the SUP05 clade under high DO (22 µM), anoxic, and low DO (3.8 µM) concentrations. We show that strain EF1 cells respire oxygen and nitrate and that cells have higher growth rates, express more genes, and fix more carbon when oxygen becomes available for aerobic respiration. Evidence that facultatively aerobic SUP05 are more active and respire nitrate when oxygen becomes available at low concentrations suggests that they are an important source of nitrite across marine OMZ boundary layers.