Cancer-associated Histone H3 N-terminal arginine mutations disrupt PRC2 activity and impair differentiation.

Dysregulated epigenetic states are a hallmark of cancer and often arise from genetic alterations in epigenetic regulators. This includes missense mutations in histones, which, together with associated DNA, form nucleosome core particles. However, the oncogenic mechanisms of most histone mutations are unknown. Here, we demonstrate that cancer-associated histone mutations at arginines in the histone H3 N-terminal tail disrupt repressive chromatin domains, alter gene regulation, and dysregulate differentiation. We find that histone H3R2C and R26C mutants reduce transcriptionally repressive H3K27me3. While H3K27me3 depletion in cells expressing these mutants is exclusively observed on the minor fraction of histone tails harboring the mutations, the same mutants recurrently disrupt broad H3K27me3 domains in the chromatin context, including near developmentally regulated promoters. H3K27me3 loss leads to de-repression of differentiation pathways, with concordant effects between H3R2 and H3R26 mutants despite different proximity to the PRC2 substrate, H3K27. Functionally, H3R26C-expressing mesenchymal progenitor cells and murine embryonic stem cell-derived teratomas demonstrate impaired differentiation. Collectively, these data show that cancer-associated H3 N-terminal arginine mutations reduce PRC2 activity and disrupt chromatin-dependent developmental functions, a cancer-relevant phenotype.

Clinicians' Perspectives on the Telehealth Serious Illness Care Program for Older Adults With Myeloid Malignancies: Single-Arm Pilot Study.

BACKGROUND: Serious illness conversations may help patients avoid unwanted treatments. We previously piloted the telehealth Serious Illness Care Program (SICP) for older adults with acute myeloid leukemia and myelodysplastic syndrome. OBJECTIVE: In this study, we aimed to understand the experience of the telehealth SICP from the clinician's perspective. METHODS: We studied 10 clinicians who delivered the telehealth SICP to 20 older adults with acute myeloid leukemia or myelodysplastic syndrome. Quantitative outcomes included confidence and acceptability. Confidence was measured using a 22-item survey (range 1-7; a higher score is better). Acceptability was measured using an 11-item survey (5-point Likert scale). Hypothesis testing was performed at α=.10 (2-tailed) due to the pilot nature and small sample size. Clinicians participated in audio-recorded qualitative interviews at the end of the study to discuss their experience. RESULTS: A total of 8 clinicians completed the confidence measure and 7 clinicians completed the acceptability measure. We found a statistically significant increase in overall confidence (mean increase of 0.5, SD 0.6; P=.03). The largest increase in confidence was in helping families with reconciliation and goodbye (mean 1.4, SD 1.5; P=.04). The majority of clinicians agreed that the format was simple (6/7, 86%) and easy to use (6/7, 86%). Clinicians felt that the telehealth SICP was effective in understanding their patients' values about end-of-life care (7/7, 100%). A total of three qualitative themes emerged: (1) the telehealth SICP deepened relationships and renewed trust; (2) each telehealth SICP visit felt unique and personal in a positive way; and (3) uninterrupted, unrushed time optimized the visit experience. CONCLUSIONS: The telehealth SICP increased confidence in having serious illness conversations while deepening patient-clinician relationships. TRIAL REGISTRATION: ClinicalTrials.gov NCT04745676; https://www.clinicaltrials.gov/study/NCT04745676.

Chemo-phosphoproteomic profiling with ATR inhibitors berzosertib and gartisertib uncovers new biomarkers and DNA damage response regulators.

The ATR kinase protects cells against DNA damage and replication stress and represents a promising anti-cancer drug target. The ATR inhibitors (ATRi) berzosertib and gartisertib are both in clinical trials for the treatment of advanced solid tumours as monotherapy or in combination with genotoxic agents. We carried out quantitative phospho-proteomic screening for ATR biomarkers that are highly sensitive to berzosertib and gartisertib, using an optimized mass spectrometry pipeline. Screening identified a range of novel ATR-dependent phosphorylation events, which were grouped into three broad classes: i) targets whose phosphorylation is highly sensitive to ATRi and which could be the next generation of ATR biomarkers; ii) proteins with known genome maintenance roles not previously known to be regulated by ATR; iii) novel targets whose cellular roles are unclear. Class iii targets represent candidate DNA damage response proteins and, with this in mind, proteins in this class were subjected to secondary screening for recruitment to DNA damage sites. We show that one of the proteins recruited, SCAF1, interacts with RNAPII in a phospho-dependent manner and recruitment requires PARP activity and interaction with RNAPII. We also show that SCAF1 deficiency partly rescues RAD51 loading in cells lacking the BRCA1 tumour suppressor. Taken together these data reveal potential new ATR biomarkers and new genome maintenance factors.

Clinical and Radiographic Outcomes Following Volar-Locked Plating Versus Dorsal Bridge Plating for Distal Radius Factures.

Purpose: Distal radius fractures (DRFs) indicated for operative intervention are most commonly treated with volar-locked plating (VLP); however, dorsal bridge plating (DBP) has been used as an alternative fixation method. The purpose of this study was to use a propensity score to match and compare the radiographic and clinical outcomes of patients undergoing isolated VLP or DBP for DRFs. Methods: We performed a retrospective, propensity score-matched analysis of patients undergoing isolated VLP or DBP treatment for isolated DRFs from 2015 to 2022 at a single level-1 trauma center. Patients were propensity score-matched by a total of eight demographic and comorbidity factors, AO Foundation/Orthopedic Trauma Association classification, and preoperative Patient-Reported Outcomes Measurement Information System (PROMIS) scores. Our primary outcomes included postoperative complications, wrist and forearm range of motion (ROM), grip strength, and radiographic measurements, including radial height, radial inclination, volar tilt, and articular step-off. Results: Overall, 415 DBP and 2075 VLP were successfully propensity score-matched and included in this study. Grip strength and ROM measurements at the 6-month follow-up, including wrist flexion, wrist extension, forearm pronation, forearm supination, radial deviation, and ulnar deviation, were increased in the VLP compared with DBP (P < .05). Complication rates among both the groups were relatively low; however, the rates of malunion and nonunion were significantly higher among the DBP group (P < .05). Radial height, radial inclination, and articular step-off were improved in the VLP group compared with the DBP group (P < .05); however, volar tilt was similar between groups. PROMIS upper extremity and physical function were significantly higher among the VLP group (P < .05). No significant difference was noted in PROMIS pain interference between the groups. Conclusions: When compared with DBP, patients undergoing VLP are more likely to have improved clinical and radiographic outcomes. Although improvement in wrist and forearm ROM and radiographic parameters is statistically significant, it may not be clinically relevant. Type of study/level of evidence: Therapeutic III.

ATRX guards against aberrant differentiation in mesenchymal progenitor cells.

Alterations in the tumor suppressor ATRX are recurrently observed in mesenchymal neoplasms. ATRX has multiple epigenetic functions including heterochromatin formation and maintenance and regulation of transcription through modulation of chromatin accessibility. Here, we show in murine mesenchymal progenitor cells (MPCs) that Atrx deficiency aberrantly activated mesenchymal differentiation programs. This includes adipogenic pathways where ATRX loss induced expression of adipogenic transcription factors and enhanced adipogenic differentiation in response to differentiation stimuli. These changes are linked to loss of heterochromatin near mesenchymal lineage genes together with increased chromatin accessibility and gains of active chromatin marks. We additionally observed depletion of H3K9me3 at transposable elements, which are derepressed including near mesenchymal genes where they could serve as regulatory elements. Finally, we demonstrated that loss of ATRX in a mesenchymal malignancy, undifferentiated pleomorphic sarcoma, results in similar epigenetic disruption and de-repression of transposable elements. Together, our results reveal a role for ATRX in maintaining epigenetic states and transcriptional repression in mesenchymal progenitors and tumor cells and in preventing aberrant differentiation in the progenitor context.

Adjunctive dorsal spanning plate fixation for challenging distal radius injuries.

Background: Distal radius fractures with severely osteoporotic bone or articular comminution can provide challenges to fixation with traditional volar locked plating alone. The purpose of this study was to evaluate the clinical, radiographic, and patient reported outcomes of patients undergoing distal radius fixation with volar locked plating and adjunctive dorsal bridge plating. Methods: We retrospectively identified 16 patients with distal radius fractures who underwent our preferred surgical technique for fixation. Patients underwent volar locked plate fixation as well as dorsal bridge fixation at time of surgery. Seven patients were indicated for severe articular comminution with volar rim fragmentation (44%), three patients were revised for nonunion after previous volar locked late fixation (19%), and six patients had severely osteoporotic bone with articular comminution (38%). Two patients (13%) sustained AO/OTA 23-A3 distal radius fracture, two patients (13%) had a 23-B3 fracture, two patients (13%) had a 23-C2 fracture and ten patients (63%) had a 23-C3 fracture. Results: The average patient age was 51.8 years ± 20.6. Patients were followed for an average of 12.2±6.3 months. The dorsal bridge plate was removed at an average of 11.1±2.4 weeks. The average post-operative radial inclination was 18.9±2.4°, radial height 12.4 mm ± 2.6 mm, and volar tilt 7.1±1.9°. There were no cases of deep or superficial infection. After dorsal bridge plate removal, patients demonstrated an average wrist extension of 55.3±9.5°, flexion 54.4±12.8°, radial deviation 15.7±3.2°, 25.2±3.9 degrees of ulnar deviation. Conclusion: Distal radius fractures in the setting of severely osteoporotic bone, salvage procedures, articular comminution, volar rim fractures, and revision surgery present uniquely difficult surgical challenges. Volar locked plating with adjunctive dorsal bridge plating can be used with good short- and long-term results.

ChatGPT-4 accuracy for patient education in laryngopharyngeal reflux.

INTRODUCTION: Chatbot Generative Pre-trained Transformer (ChatGPT) is an artificial intelligence-powered language model chatbot able to help otolaryngologists in practice and research. The ability of ChatGPT in generating patient-centered information related to laryngopharyngeal reflux disease (LPRD) was evaluated. METHODS: Twenty-five questions dedicated to definition, clinical presentation, diagnosis, and treatment of LPRD were developed from the Dubai definition and management of LPRD consensus and recent reviews. Questions about the four aforementioned categories were entered into ChatGPT-4. Four board-certified laryngologists evaluated the accuracy of ChatGPT-4 with a 5-point Likert scale. Interrater reliability was evaluated. RESULTS: The mean scores (SD) of ChatGPT-4 answers for definition, clinical presentation, additional examination, and treatments were 4.13 (0.52), 4.50 (0.72), 3.75 (0.61), and 4.18 (0.47), respectively. Experts reported high interrater reliability for sub-scores (ICC = 0.973). The lowest performances of ChatGPT-4 were on answers about the most prevalent LPR signs, the most reliable objective tool for the diagnosis (hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring (HEMII-pH)), and the criteria for the diagnosis of LPR using HEMII-pH. CONCLUSION: ChatGPT-4 may provide adequate information on the definition of LPR, differences compared to GERD (gastroesophageal reflux disease), and clinical presentation. Information provided upon extra-laryngeal manifestations and HEMII-pH may need further optimization. Regarding the recent trends identifying increasing patient use of internet sources for self-education, the findings of the present study may help draw attention to ChatGPT-4's accuracy on the topic of LPR.

Comparative genomics incorporating translocation renal cell carcinoma mouse model reveals molecular mechanisms of tumorigenesis.

Translocation renal cell carcinoma (tRCC) most commonly involves an ASPSCR1-TFE3 fusion, but molecular mechanisms remain elusive and animal models are lacking. Here, we show that human ASPSCR1-TFE3 driven by Pax8-Cre (a credentialed clear cell RCC driver) disrupted nephrogenesis and glomerular development, causing neonatal death, while the clear cell RCC failed driver, Sglt2-Cre, induced aggressive tRCC (as well as alveolar soft part sarcoma) with complete penetrance and short latency. However, in both contexts, ASPSCR1-TFE3 led to characteristic morphological cellular changes, loss of epithelial markers, and an epithelial-mesenchymal transition. Electron microscopy of tRCC tumors showed lysosome expansion, and functional studies revealed simultaneous activation of autophagy and mTORC1 pathways. Comparative genomic analyses encompassing an institutional human tRCC cohort (including a hitherto unreported SFPQ-TFEB fusion) and a variety of tumorgraft models (ASPSCR1-TFE3, PRCC-TFE3, SFPQ-TFE3, RBM10-TFE3, and MALAT1-TFEB) disclosed significant convergence in canonical pathways (cell cycle, lysosome, and mTORC1) and less established pathways such as Myc, E2F, and inflammation (IL-6/JAK/STAT3, interferon-γ, TLR signaling, systemic lupus, etc.). Therapeutic trials (adjusted for human drug exposures) showed antitumor activity of cabozantinib. Overall, this study provides insight into MiT/TFE-driven tumorigenesis, including the cell of origin, and characterizes diverse mouse models available for research.

Predicting Acute Median Neuropathy in Perilunate Injuries.

Purpose: Perilunate fracture dislocation (PLFD) injuries are associated with the development of acute carpal tunnel syndrome (CTS). The purpose of our study was to identify the factors that increase the likelihood of developing CTS in patients with PLFD. Additionally, we attempted to classify patients who did not initially undergo carpal tunnel release (CTR) at the time of injury but eventually underwent CTR within the follow-up period. Methods: Patients presenting to a level-1 trauma center with isolated PLFDs (Mayfield III-IV) were retrospectively identified by using CPT and ICD-10 codes. Polytraumatized patients, those with a history of previous wrist trauma, or those with previous carpal tunnel symptoms or surgery were excluded. Outcomes of interest included the development of acute CTS, pre- and post-reduction changes in CTS symptoms, and associated hand and wrist fractures. Chi-square tests, Kruskal-Wallis tests, and multivariate logistic regression were used to examine the predictors of developing CTS after a PLFD. Results: In total, 43 patients were included in the final cohort, with a mean age of 44 years, of which 77% were men. The most common fracture of the carpus included scaphoid fractures (9/43, 21%). The average time from presentation to reduction was 636 minutes. Acute CTS symptoms before reduction were present in 26% of the patients and increased post-reduction to 28%. No difference exists between the time to sedation and the presence of acute carpal tunnel symptoms (P >.05). During initial surgical intervention, 79% underwent CTR (27/34). Of the seven patients who did not initially undergo a CTR, 57% (4/7) required a CTR within the follow-up period. Conclusion: Reduction of PLFDs did not significantly improve the number of patients with acute CTS. More than 50% of the patients who did not undergo a CTR at the initial surgery required a CTR within the follow-up period. Type of study/level of evidence: Prognostic III.

Cell-type-specific CAG repeat expansions and toxicity of mutant Huntingtin in human striatum and cerebellum.

Brain region-specific degeneration and somatic expansions of the mutant Huntingtin (mHTT) CAG tract are key features of Huntington's disease (HD). However, the relationships among CAG expansions, death of specific cell types and molecular events associated with these processes are not established. Here, we used fluorescence-activated nuclear sorting (FANS) and deep molecular profiling to gain insight into the properties of cell types of the human striatum and cerebellum in HD and control donors. CAG expansions arise at mHTT in striatal medium spiny neurons (MSNs), cholinergic interneurons and cerebellar Purkinje neurons, and at mutant ATXN3 in MSNs from SCA3 donors. CAG expansions in MSNs are associated with higher levels of MSH2 and MSH3 (forming MutSß), which can inhibit nucleolytic excision of CAG slip-outs by FAN1. Our data support a model in which CAG expansions are necessary but may not be sufficient for cell death and identify transcriptional changes associated with somatic CAG expansions and striatal toxicity.

Histologic Evaluation of Silk-Hyaluronic Acid After Human Vocal Fold Injection.

OBJECTIVES: This case report aims to histologically examine human vocal fold tissue 9 months after silk-hyaluronic acid (silk-HA) injection. INTRODUCTION: Silk-HA is an engineered injectable implant made from natural protein biomaterial, silk, crosslinked with hyaluronic acid to provide long-lasting, dynamic office-based vocal fold injection augmentation to restore glottic competency. METHODS: We report the case of an adult female with left vocal fold immobility and bilateral atrophy that was treated with silk-HA injections with biopsy taken 9 months after injection for histological examination. CONCLUSION: Silk-HA injection in human true vocal fold demonstrates slow degradation of particles and intended cellular infiltration 9 months after injection.

A Novel Education System to Createcustomized Primary Palliative Care Curricula for Training Programs.

Clinicians need palliative care (PC) skills to provide good patient care. Primary PC (PPC) is the PC knowledge and skills provided by non-PC specialists and are distinct from specialist PC (SPC), the complex interventions provided by specialty trained clinicians. There is no consensus as to the specific PPC knowledge and skills that should be taught or the methods that should be used. We describe an educational system that incorporates a suite of tools that PC educators can easily adapt to the PC educational requests of training programs to evaluate the PPC educational needs of training programs and then to create customized educational programs that regularly adjusts to the input of trainees and faculty. We hope others can use this program to decrease the burden on the PC educators and provide a tailored PPC education program for training programs within their institutions.

Telehealth serious illness care program for older adults with hematologic malignancies: a single-arm pilot study.

ABSTRACT: Older patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) feel shocked and bewildered when diagnosed. Serious illness conversations (SICs) may increase disease understanding and preparations for the future. However, SICs often happen late, in part because of clinician-perceived patient discomfort. Telehealth may promote patient comfort by allowing SICs to take place at home. This study assesses the feasibility and usability of a telehealth-delivered Serious Illness Care Program (SICP) for older adults with AML and MDS. We conducted a single-arm pilot study including 20 older adults with AML and MDS. Feasibility was measured using retention rate, with >80% considered feasible. Usability was measured using telehealth usability questionnaire (TUQ; range, 1-7): >5 considered usable. We collected other outcomes including acceptability and disease understanding and conducted post-visit qualitative interviews to elicit feedback. Hypothesis testing was performed at α = 0.10 owing to the pilot nature and small sample size. Retention rate was 95% (19/20); mean TUQ scores were 5.9 (standard deviation [SD], 0.9) and 5.9 (SD, 1.1) for patients and caregivers, respectively. We found the SICP to be acceptable. The majority of patients found the SICP to be very or extremely worthwhile (88.2%; 15/17), and reported it increased closeness with their clinician (75.0%; 12/16). After their visit, patient estimates of curability, and overall life expectancy aligned more closely with those of their clinicians. In qualitative interviews, most patients said that they would recommend this program to others (89.5%, 17/19). This study demonstrated that delivery of the telehealth SICP to older patients with AML and MDS is feasible, usable, and acceptable. This trial is registered at www.clinicaltrials.gov as #NCT04745676.

Wrist Extensor Tenosynovitis After COVID-19 Vaccination.

We present the case of a 54-year-old right-handed woman with no medical history of rheumatic disease or trauma to the upper extremities who developed painful nodules along her left upper extremity and torso immediately after receiving the mRNA-1273 SARS-CoV-2 vaccine booster for COVID-19 in her left upper extremity. Most of the nodules subsided within several days, but several persisted over the dorsum of the left wrist with physical examination and imaging findings consistent with second and fourth extensor compartment tenosynovitis. She ultimately underwent excision of the left wrist extensor tenosynovitis, followed by a repeat excision for recurrence of symptoms.

Is it Always Laryngopharyngeal Reflux? How Voice Disorders Can Manifest as LPR

Introduction: Laryngopharyngeal reflux (LPR) manifests with a constellation of common throat symptoms and inconclusive signs on laryngoscopic exam. It is a diagnosis, often made clinically, that can lead to prescriptions of proton pump inhibitors that are unnecessary and potentially harmful. Glottic insufficiency (GI) and the accompanying hyperfunctional laryngeal behaviors can also present with similar, common throat complaints that may or may not include a qualitative change to the voice. Methods: This is a reflection article. It is written to summarize, explain, and support with evidence the opinion of the author on the topic of how symptoms of voice disorders can easily be mistaken for symptoms of LPR. The offered reflection is based on his experience, research and the available literature. Reflection: This article intends to explore the similarities between GI and LPR, how to ultimately differentiate them and how to approach treatment with a broader differential diagnosis. Conclusion: LPR and GI can present with identical, vague throat, and voice symptoms. Empiric medication trials, behavioral interventions and objective laryngovideostroboscopy, impedance-based reflux, and esophageal motility testing may all be needed, sometimes in a trial and error fashion, to correctly diagnose and treat a patient's symptoms.

Introducción: El reflujo laríngeo-faríngeo (LPR, por sus siglas en inglés) se manifiesta con una serie de síntomas comunes en la garganta y signos no concluyentes en el examen larinoscópico. Es un diagnóstico que a menudo se realiza clínicamente y que puede llevar a la prescripción de inhibidores de la bomba de protones que son innecesarios y potencialmente perjudiciales. La insuficiencia glótica (IG) y los comportamientos laríngeos hiperfuncionales que la acompañan también pueden presentar síntomas de garganta comunes similares, que pueden o no incluir un cambio cualitativo en la voz. Métodos: Este es un artículo de reflexión. Está escrito para resumir, explicar y respaldar con evidencia la opinión del autor sobre cómo los síntomas de los trastornos de la voz pueden confundirse fácilmente con los síntomas del LPR. La reflexión ofrecida se basa en su experiencia, investigación y la literatura disponible. Reflexión: Este artículo tiene la intención de explorar las similitudes entre la IG y el LPR, cómo diferenciarlos finalmente y cómo abordar el tratamiento con un diagnóstico diferencial más amplio. Conclusión: El LPR y la IG pueden presentar síntomas idénticos y vagos en la garganta y la voz. Puede ser necesario realizar ensayos de medicación empírica, intervenciones conductuales y pruebas objetivas de laringovideostroboscopia, reflujo basado en impedancia y motilidad esofágica, a veces de manera experimental, para diagnosticar y tratar correctamente los síntomas de un paciente.

Diagnosis of Ulnar Neuropathy at the Elbow Using Ultrasound - A Comparison to Electrophysiologic Studies.

PURPOSE: Given the relatively high false negative rate of electrodiagnostic studies (EDX) in patients with clinically diagnosed ulnar neuropathy at the elbow (UNE), we sought to determine whether an alternative objective test could more effectively detect UNE. Additionally, we proposed to determine the relationship between the cross-sectional area (CSA) of the ulnar nerve on ultrasound (US), EDX, and clinical symptoms. METHODS: This was a retrospective study of patients presenting with symptomatic UNE. The performance characteristics of EDX versus ultrasound were calculated using the clinical diagnosis of UNE as the reference standard. Standard EDX studies and US of the ulnar nerve were analyzed. Maximal CSA of the ulnar nerve and EDX severity were analyzed for patients with each combination of US-positive/negative and EDX-positive/negative findings. RESULTS: Analysis was performed on 89 patients and 115 nerves with signs and symptoms of cubital tunnel syndrome. In total, 56 (49%) nerves were diagnosed as mild UNE, 32 (28%) nerves were diagnosed as moderate UNE, 17 (15%) nerves were diagnosed as severe UNE, and 10 (8%) nerves were negative for UNE by EDX. Maximal-maximal CSA was highly correlated with disease severity as determined by nerve conduction studies/electromyography. Compared with EDX+/US+, patients with EDX-/US+ showed higher rates of ulnar sensory loss and elbow tenderness with similar rates of positive Tinel and intrinsic muscle atrophy. In this sample of patients with clinically diagnosed UNE, 91.3% of the patients demonstrated positive EDX studies, whereas 94.8% had a positive US. CONCLUSIONS: Ultrasound is an alternative to EDX that could be incorporated clinically in the diagnosis and management of UNE. Ultrasound was able to consistently detect clinically positive cubital tunnel syndrome demonstrating its utility as a confirmatory or supplemental test to the clinical assessment if one is required. Ultrasound additionally may be able to better identify patients with early stages of UNE with negative EDX findings. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.

ATRX guards against aberrant differentiation in mesenchymal progenitor cells.

Alterations in the tumor suppressor ATRX are recurrently observed in several cancer types including sarcomas, which are mesenchymal neoplasms. ATRX has multiple epigenetic functions including heterochromatin formation and maintenance and regulation of transcription through modulation of chromatin accessibility. Here, we show in murine mesenchymal progenitor cells (MPCs) that Atrx deficiency aberrantly activated mesenchymal differentiation programs. This includes adipogenic pathways where ATRX loss induced expression of adipogenic transcription factors (Pparγ and Cebpα) and enhanced adipogenic differentiation in response to differentiation stimuli. These changes are linked to loss of heterochromatin near mesenchymal lineage genes together with increased chromatin accessibility and gains of active chromatin marks at putative enhancer elements and promoters. Finally, we observed depletion of H3K9me3 at transposable elements, which are derepressed including near mesenchymal genes where they could serve as regulatory elements. Our results demonstrate that ATRX functions to buffer against differentiation in mesenchymal progenitor cells, which has implications for understanding ATRX loss of function in sarcomas.

Tumor monocyte content predicts immunochemotherapy outcomes in esophageal adenocarcinoma.

For inoperable esophageal adenocarcinoma (EAC), identifying patients likely to benefit from recently approved immunochemotherapy (ICI+CTX) treatments remains a key challenge. We address this using a uniquely designed window-of-opportunity trial (LUD2015-005), in which 35 inoperable EAC patients received first-line immune checkpoint inhibitors for four weeks (ICI-4W), followed by ICI+CTX. Comprehensive biomarker profiling, including generation of a 65,000-cell single-cell RNA-sequencing atlas of esophageal cancer, as well as multi-timepoint transcriptomic profiling of EAC during ICI-4W, reveals a novel T cell inflammation signature (INCITE) whose upregulation correlates with ICI-induced tumor shrinkage. Deconvolution of pre-treatment gastro-esophageal cancer transcriptomes using our single-cell atlas identifies high tumor monocyte content (TMC) as an unexpected ICI+CTX-specific predictor of greater overall survival (OS) in LUD2015-005 patients and of ICI response in prevalent gastric cancer subtypes from independent cohorts. Tumor mutational burden is an additional independent and additive predictor of LUD2015-005 OS. TMC can improve patient selection for emerging ICI+CTX therapies in gastro-esophageal cancer.

Genetically engineering endothelial niche in human kidney organoids enables multilineage maturation, vascularization and de novo cell types.

Vascularization plays a critical role in organ maturation and cell type development. Drug discovery, organ mimicry, and ultimately transplantation in a clinical setting thereby hinges on achieving robust vascularization of in vitro engineered organs. Here, focusing on human kidney organoids, we overcome this hurdle by combining an inducible ETS translocation variant 2 (ETV2) human induced pluripotent stem cell (iPSC) line, which directs endothelial fate, with a non-transgenic iPSC line in suspension organoid culture. The resulting human kidney organoids show extensive vascularization by endothelial cells with an identity most closely related to endogenous kidney endothelia. Vascularized organoids also show increased maturation of nephron structures including more mature podocytes with improved marker expression, foot process interdigitation, an associated fenestrated endothelium, and the presence of renin+ cells. The creation of an engineered vascular niche capable of improving kidney organoid maturation and cell type complexity is a significant step forward in the path to clinical translation. Furthermore, this approach is orthogonal to native tissue differentiation paths, hence readily adaptable to other organoid systems and thus has the potential for a broad impact on basic and translational organoid studies.