Hypoxanthine in the microenvironment can enable thiopurine resistance in acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy, with relapse being a major obstacle to successful treatment. Our understanding of the mechanisms driving chemotherapy resistance and ultimately relapse in leukemia remains incomplete. Herein, we investigate the impact of the tumor microenvironment on leukemia cell drug responses using human plasma-like media (HPLM), designed to mimic physiological conditions more accurately ex vivo. We demonstrate that while most chemotherapeutics maintain an efficacy in HPLM comparable to standard tissue culture media, the thiopurines 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG) exhibit significantly reduced potency and efficacy against both B- and T- leukemia cells in HPLM. By merging our understanding of thiopurines' mechanism of action with the metabolites supplemented in HPLM compared to standard media, we proposed and subsequently validated the hypothesis that hypoxanthine, a purine derivative, is responsible for conferring resistance to the thiopurines. Importantly, the concentration of hypoxanthine required for resistance is comparable to physiological levels found in vivo, supporting clinical relevance. Our findings demonstrate the utility of a more physiologic media in identifying and characterizing mechanisms by which the microenvironment can enable resistance. Understanding such interactions may inform strategies to overcome drug resistance and improve therapeutic outcomes in pediatric leukemia.

A trans-eyebrow zig-zag approach for frontal bone fractures✰.

Frontal bone fractures are amongst the most common facial fractures and surgical management, which has traditionally involved access via a coronal flap, can result in unsightly scarring, alopecia, paraesthesia, facial nerve weakness and temporal hollowing. Alternative approaches include use of endoscopically-assisted surgery, often through the eyebrow, which minimises the risk of unsightly scarring but may also sacrifice access in the process. In this technical note, we discuss a surgical technique for open reduction and internal fixation of fractures of the bone overlying the frontal sinus and supra-orbital rim, which the authors have not found in the literature, which involves the making of a "zig-zag" incision through the eyebrow in a trichophytic manner which reduces the risk of unsightly scarring whilst simultaneously allowing for sufficient surgical access to the fracture site.

Rapid or Immediate ART, HIV Stigma, Medical Mistrust, and Retention in Care: An Exploratory Mixed Methods Pilot Study.

Rapid or immediate antiretroviral therapy (iART) after HIV diagnosis improves linkage to care and time to viral suppression. However, iART may affect or be affected by HIV-related stigma and medical mistrust. In this mixed-methods pilot study, we examined the bi-directional role of HIV stigma, medical mistrust, and visit adherence (VA) in the context of iART in a diverse, newly diagnosed patient population. Participants were recruited from an HIV clinic in New York City and we utilized a convergent parallel design integrating quantitative data from demographic surveys, the HIV Stigma Survey (HIVSS), the Medical Mistrust Index (MMI) and electronic medical records, and qualitative data from in-depth interviews. Among the sample (N = 30), 26% (N = 8) initiated ART same-day or within 3 days, while the majority (N = 17) initiated between 4 and 30 days, and 17% (N = 5) initiated ART > 30 days. The median (range) age was 35, and most were English-speaking, Black or Hispanic men and identified as gay. Time to ART initiation was associated with time to linkage to care and time to viral suppression. Day 0-3 group's major theme was iART as stigma prevention, and they had the highest mean HIVSS, lowest MMI score, and a visit adherence of 0.86. Day 4-30 group's major theme was alleviation of internalized stigma, and they had the lowest mean HIVSS score, and highest visit adherence of 0.91. Day > 30 group's major theme was exacerbation of perceived or anticipated stigma, had the highest MMI score and a visit adherence of 0.85. iART implementation requires equitable strategies that address HIV-stigma and mistrust.

Availability and use of web-based interventions for patients with head and neck cancer: a scoping review.

PURPOSE: To identify and review the nature, scope and use of web-based interventions for patients with head and neck cancer (HNC). METHOD: A scoping review guided by the methodological framework described by the Joanna Briggs Institute was performed to review empirical studies and websites. Seven electronic databases (CINAHL, Medline, Scopus, Embase, Cochrane, PubMed and PsycInfo) were searched from 2010 to 2020, data extracted and synthesised using thematic analysis. The Google search engine was employed, identifying the first 100 websites, using the search term head and neck cancer. Websites meeting eligibility criteria were assessed using the QUEST analysis tool, and descriptively summarised. RESULTS: Thirteen empirical studies and 32 websites were included. As identified by empirical studies, web-based interventions were developed to provide (1) patient information on HNC and related treatments, (2) advice and support during treatment and (3) management strategies promoting adjustment to life with and beyond HNC. The reviewed websites provided minimal information to aid shared decision-making and facilitate preparedness for treatment, with few utilising patient narratives. Web-based interventions for HNC patients were mainly text based and focused on survivorship. CONCLUSIONS: There is a paucity of theory-based, co-designed web-based interventions using patient narratives. IMPLICATIONS FOR CANCER SURVIVORS: As patients increasingly look to the internet for advice and support, healthcare professionals are in a position to provide high-quality web-based interventions. There is an opportunity to rigorously develop a web-based intervention, containing narratives of peoples' lives before and after HNC treatment, aiding decision-making, preparedness for treatment and self-management.

CXCR4 antagonists disrupt leukaemia-meningeal cell adhesion and attenuate chemoresistance.

The effective prophylaxis and treatment of central nervous system (CNS) involvement in acute lymphoblastic leukaemia (ALL) remains a significant clinical challenge. Developing novel and more effective CNS-directed therapies has been hampered, in part, by our limited understanding of the leukaemia niche in the CNS relative to the bone marrow. Accordingly, defining the molecular and cellular components critical for the establishment and maintenance of the CNS leukaemia niche may lead to new therapeutic opportunities. In prior work we showed that direct intercellular interactions between leukaemia and meningeal cells enhance leukaemia chemoresistance in the CNS. Herein, we show that the CXCR4/CXCL12 chemokine axis contributes to leukaemia-meningeal cell adhesion. Importantly, clinically tested CXCR4 antagonists, which are likely to cross the blood-brain and blood-cerebral spinal fluid barriers and penetrate the CNS, effectively disrupted leukaemia-meningeal cell adhesion. Moreover, by disrupting these intercellular interactions, CXCR4 antagonists attenuated leukaemia chemoresistance in leukaemia-meningeal cell co-culture experiments and enhanced the efficacy of cytarabine in targeting leukaemia cells in the meninges in vivo. This work identifies the CXCR4/CXCL12 axis as an important regulator of intercellular interactions within the CNS leukaemia niche and supports further testing of the therapeutic efficacy of CXCR4 antagonists in overcoming CNS niche-mediated chemoresistance.

Inhibitor of DNA binding 2 (ID2) regulates the expression of developmental genes and tumorigenesis in ewing sarcoma.

Sarcomas are difficult to treat and the therapy, even when effective, is associated with long-term and life-threatening side effects. In addition, the treatment regimens for many sarcomas, including Ewing sarcoma, rhabdomyosarcoma, and osteosarcoma, are relatively unchanged over the past two decades, indicating a critical lack of progress. Although differentiation-based therapies are used for the treatment of some cancers, the application of this approach to sarcomas has proven challenging. Here, using a CRISPR-mediated gene knockout approach, we show that Inhibitor of DNA Binding 2 (ID2) is a critical regulator of developmental-related genes and tumor growth in vitro and in vivo in Ewing sarcoma tumors. We also identified that homoharringtonine, which is an inhibitor of protein translation and FDA-approved for the treatment of leukemia, decreases the level of the ID2 protein and significantly reduces tumor growth and prolongs mouse survival in an Ewing sarcoma xenograft model. Furthermore, in addition to targeting ID2, homoharringtonine also reduces the protein levels of ID1 and ID3, which are additional members of the ID family of proteins with well-described roles in tumorigenesis, in multiple types of cancer. Overall, these results provide insight into developmental regulation in Ewing sarcoma tumors and identify a novel, therapeutic approach to target the ID family of proteins using an FDA-approved drug.

Individualized Provider Feedback Increased HIV and HCV Screening and Identification in a New York City Emergency Department.

Efforts to end the HIV and hepatitis C virus (HCV) epidemics begin with ascertainment of a person's infection status through screening. Despite its importance as a site of testing, missed opportunities for screening in the Emergency Department (ED) are common. We describe the impact of implementing an individualized provider feedback intervention on HIV and HCV testing in a quaternary ED. We conducted an interrupted time series analysis to evaluate the impact of the intervention on weekly HIV and HCV screening in an observational cohort of patients seeking care in the ED. The intervention included a physician champion individualized feedback with peer comparisons to all providers in the ED and an existing HIV/HCV testing and response team. Data were abstracted from the electronic medical record (EMR) for 30 weeks before, during, and after implementing the intervention. We used Poisson regression analysis to estimate changes in the weekly counts and rates of HIV and HCV testing. The incidence rate ratios (IRRs) of HIV testing were 1.94 [95% confidence interval (CI) 1.85-2.04] and 1.38 (95% CI 1.31-1.45) times higher for the intervention and post-intervention period compared with the pre-intervention period. The IRRs of HCV testing was 6.96 (95% CI 6.40-7.58) and 4.70 (95% CI 4.31-5.13) for the intervention and post-intervention periods. There were no meaningful differences in demographic characteristics during the observation period. The intervention meaningfully increased HIV and HCV testing volume and positive case detection, including testing in high-risk groups like young adults and individuals without prior testing. Although diminished, the intervention effect sustained in the 30-week period following implementation.

Therapeutic Leukapheresis in Pediatric Leukemia: Utilization Trend and Early Outcomes in a US Nationwide Cohort.

Leukapheresis (LA) in pediatric leukemia is performed for leukostasis, a life-threatening emergency in the setting of extremely increased blast cell counts. The authors aimed to assess the epidemiology of pediatric leukemia who received LA. The authors reviewed US nationally representative admission records of patients less than 20 years of age in the Kids' Inpatient Database for the years 2000, 2003, 2006, 2009, 2012, and 2016. Incidence of new leukemia cases who underwent LA were calculated for the years 2009, 2012, and 2016. Cox and logistic regression analyses were performed to ascertain the risk factors for adverse outcomes. There were 526 admissions for pediatric patients with acute lymphoblastic leukemia (ALL) (n=328), acute myeloid leukemia (AML) (n=124), or chronic myeloid leukemia (CML) (n=74) who underwent LA over the study period. The incidence of leukemia cases that required LA was lower in 2016 than in 2009 or 2012 (1.4%, 2.2%, and 2.7%, respectively; P=0.001). In-hospital mortality was higher in AML than ALL (hzard ratio, 3.2; 95% confidence interval, 1.1-9.1). None with CML died during admission. This first population-based study of LA in pediatric leukemia showed a decreased utilization of LA over recent years. The higher inpatient mortality in AML, as compared with ALL or CML, warrant further investigations.

CD99 antibody disrupts T-cell acute lymphoblastic leukemia adhesion to meningeal cells and attenuates chemoresistance.

Central nervous system (CNS) relapse is a significant cause of treatment failure among patients with acute lymphoblastic leukemia. In prior work we found that the meninges, the thin layer of tissue that covers the brain and spinal cord, harbor leukemia cells in the CNS. Importantly, direct interactions between leukemia and meningeal cells enabled leukemia chemoresistance. Herein, we show that an antibody targeting CD99, a transmembrane protein expressed on meningeal cells and many leukemia cells, disrupts adhesion between leukemia and meningeal cells and restores sensitivity of the leukemia cells to chemotherapy. This work identifies a mechanism regulating critical intercellular interactions within the CNS leukemia niche and may lead to novel therapeutic approaches for overcoming niche-mediated chemoresistance.

Macrophages orchestrate the expansion of a proangiogenic perivascular niche during cancer progression.

Tumor-associated macrophages (TAMs) are a highly plastic stromal cell type that support cancer progression. Using single-cell RNA sequencing of TAMs from a spontaneous murine model of mammary adenocarcinoma (MMTV-PyMT), we characterize a subset of these cells expressing lymphatic vessel endothelial hyaluronic acid receptor 1 (Lyve-1) that spatially reside proximal to blood vasculature. We demonstrate that Lyve-1+ TAMs support tumor growth and identify a pivotal role for these cells in maintaining a population of perivascular mesenchymal cells that express α-smooth muscle actin and phenotypically resemble pericytes. Using photolabeling techniques, we show that mesenchymal cells maintain their prevalence in the growing tumor through proliferation and uncover a role for Lyve-1+ TAMs in orchestrating a selective platelet-derived growth factor­CC­dependent expansion of the perivascular mesenchymal population, creating a proangiogenic niche. This study highlights the inter-reliance of the immune and nonimmune stromal network that supports cancer progression and provides therapeutic opportunities for tackling the disease.

Attitudes and Perceived Barriers to Sexually Transmitted Infection Screening Among Graduate Medical Trainees.

ABSTRACT: Graduate medical training is an opportune time to improve provider delivery of sexually transmitted infection (STI) screening. A survey of trainees found that the majority feel STI screening is their job but identified barriers to successful screening. Training that intentionally address service-specific barriers will be valuable in ending the STI epidemic.

Synergistic T cell signaling by 41BB and CD28 is optimally achieved by membrane proximal positioning within parallel chimeric antigen receptors.

Second generation (2G) chimeric antigen receptors (CARs) contain a CD28 or 41BB co-stimulatory endodomain and elicit remarkable efficacy in hematological malignancies. Third generation (3G) CARs extend this linear blueprint by fusing both co-stimulatory units in series. However, clinical impact has been muted despite compelling evidence that co-signaling by CD28 and 41BB can powerfully amplify natural immune responses. We postulate that effective dual co-stimulation requires juxta-membrane positioning of endodomain components within separate synthetic receptors. Consequently, we designed parallel (p)CARs in which a 2G (CD28+CD3ζ) CAR is co-expressed with a 41BB-containing chimeric co-stimulatory receptor. We demonstrate that the pCAR platform optimally harnesses synergistic and tumor-dependent co-stimulation to resist T cell exhaustion and senescence, sustaining proliferation, cytokine release, cytokine signaling, and metabolic fitness upon repeated stimulation. When engineered using targeting moieties of diverse composition, affinity, and specificity, pCAR T cells consistently elicit superior anti-tumor activity compared with T cells that express traditional linear CARs.

Successful Rituximab Monotherapy in Advanced-stage, Epstein-Barr Virus-positive Diffuse Large B-Cell Lymphoma in an Adolescent With Systemic Juvenile Idiopathic Arthritis.

Epstein-Barr virus-positive diffuse large B-cell lymphoma (EBV+ DLBCL) in pediatrics most commonly occurs as an iatrogenic immunodeficiency-associated lymphoproliferative disease. We report an 18-year-old female individual with refractory systemic juvenile idiopathic arthritis, treated with multiple immunosuppressive agents, who was diagnosed with stage III, EBV+ DLBCL. The patient achieved sustained complete remission after 4 weekly doses of rituximab monotherapy and reduction of immunosuppression. This case suggests that a post-transplant lymphoproliferative disease-like treatment approach can be a safe and effective therapy in a nontransplant, yet severely immunosuppressed, patient with EBV+ DLBCL.

The translational repressor 4E-BP1 regulates RRM2 levels and functions as a tumor suppressor in Ewing sarcoma tumors.

Ribonucleotide reductase (RNR), which is a heterodimeric tetramer composed of RRM1 and RRM2 subunits, is the rate-limiting enzyme in the synthesis of deoxyribonucleoside triphosphates (dNTPs) and essential for both DNA replication and the repair of DNA damage. The activity of RNR is coordinated with the cell cycle and regulated by fluctuations in the level of the RRM2 subunit. Multiple cancer types, including Ewing sarcoma tumors, are sensitive to inhibitors of RNR or a reduction in the levels of either the RRM1 or RRM2 subunits of RNR. Here, we show that the expression of the RRM2 protein is dependent on active protein synthesis and that 4E-BP1, a repressor of cap-dependent protein translation, specifically regulates the level of the RRM2 protein. Furthermore, inhibition of mTORC1/2, but not mTORC1, activates 4E-BP1, inhibits protein synthesis, and reduces the level of the RRM2 protein in multiple sarcoma cell lines. This effect of mTORC1/2 inhibitors on protein synthesis and RRM2 levels was rescued in cell lines with the CRISPR/Cas9-mediated knockout of 4E-BP1. In addition, the inducible expression of a mutant 4E-BP1 protein that cannot be phosphorylated by mTOR blocked protein synthesis and inhibited the growth of Ewing sarcoma cells in vitro and in vivo in a xenograft. Overall, these results provide insight into the multifaceted regulation of RRM2 protein levels and identify a regulatory link between protein translation and DNA replication.

Body mass index associated with childhood and adolescent high-risk B-cell acute lymphoblastic leukemia risk: A Children's Oncology Group report.

BACKGROUND: Obesity is a risk factor for many adulthood cancers, but its role in childhood, adolescent, and young adult (AYA) cancer is unknown. Childhood and AYA acute lymphoblastic leukemia (ALL) incidence and obesity prevalence have shown concurrent increases. We sought to identify whether obesity may be a risk factor for childhood and AYA ALL. METHODS: Characteristics from individuals with ALL, aged 2-30 years, diagnosed 2004-2017 and treated on Children's Oncology Group (COG) protocols with available pre-treatment anthropometric data (N = 4726) were compared to National Health and Nutrition Examination Survey controls (COG AALL17D2). Body mass index (BMI) was defined using standard CDC definitions. Multivariate conditional logistic regression assessed associations between BMI and ALL with additional analyses stratified by sex and race/ethnicity. RESULTS: Among cases (72% high-risk (HR) B-ALL, 28% T-ALL), 5% had underweight, 58% normal weight, 17% overweight, and 20% obesity. Underweight (OR 2.11, 95% CI 1.56-2.85) and obesity (OR 1.32, 95% CI 1.15-1.53) were associated with B-ALL diagnosis. Specifically, obesity was associated with B-ALL among males (OR 1.57, 95% CI 1.30-1.91) and Hispanic children (OR 1.78, 95% CI 1.39-2.29). Obesity was also associated with central nervous system (CNS) involvement. CONCLUSION: Pre-treatment obesity is associated with HR B-ALL among males and Hispanics, as well as with CNS involvement, suggesting common physiology between obesity and leukemogenesis. An association between underweight and ALL was confirmed, likely due to cancer-associated wasting. These results have important public health implications for obesity prevention and treatment in children and adolescents to reduce cancer risk.

The meninges enhance leukaemia survival in cerebral spinal fluid.

Central nervous system (CNS) relapse is a common cause of treatment failure in patients with acute lymphoblastic leukaemia (ALL) despite current CNS-directed therapies that are also associated with significant short- and long-term toxicities. Herein, we showed that leukaemia cells exhibit decreased proliferation, elevated reactive oxygen species (ROS) and increased cell death in cerebral spinal fluid (CSF) both in vitro and in vivo. However, interactions between leukaemia and meningeal cells mitigated these adverse effects. This work expands our understanding of the pathophysiology of CNS leukaemia and suggests novel therapeutic approaches for more effectively targeting leukaemia cells in the CNS.

Disrupting the leukemia niche in the central nervous system attenuates leukemia chemoresistance.

Protection from acute lymphoblastic leukemia relapse in the central nervous system (CNS) is crucial to survival and quality of life for leukemia patients. Current CNS-directed therapies cause significant toxicities and are only partially effective. Moreover, the impact of the CNS microenvironment on leukemia biology is poorly understood. In this study we showed that leukemia cells associated with the meninges of xenotransplanted mice, or co-cultured with meningeal cells, exhibit enhanced chemoresistance due to effects on both apoptosis balance and quiescence. From a mechanistic standpoint, we found that leukemia chemoresistance is primarily mediated by direct leukemia-meningeal cell interactions and overcome by detaching the leukemia cells from the meninges. Next, we used a co-culture adhesion assay to identify drugs that disrupted leukemia-meningeal adhesion. In addition to identifying several drugs that inhibit canonical cell adhesion targets we found that Me6TREN (Tris[2-(dimethylamino)ethyl]amine), a novel hematopoietic stem cell-mobilizing compound, also disrupted leukemia-meningeal adhesion and enhanced the efficacy of cytarabine in treating CNS leukemia in xenotransplanted mice. This work demonstrates that the meninges exert a critical influence on leukemia chemoresistance, elucidates mechanisms of relapse beyond the well-described role of the blood-brain barrier, and identifies novel therapeutic approaches for overcoming chemoresistance.

Mixed epithelial and stromal tumor after pediatric kidney transplant.

MEST of the kidney are a benign group of tumors with very rare incidence of malignant transformation. First described in 1998, this tumor has never been reported in a transplanted organ before. We present a unique case of de novo MEST in a donor kidney 4 years after transplant into a pediatric patient. Although removal of the lesions is curative without risking malignant transformation, in this case, surgical removal was not attempted to prevent reduction in transplant longevity. In this unique report of MEST in a transplanted kidney, we describe the patient/transplant outcomes without MEST resection.