Volatile organic compounds and mortality from ischemic heart disease: A case-cohort study.

Background: Volatile organic compounds (VOCs) are major components of air pollution and tobacco smoke, two known risk factors for cardiovascular diseases. VOCs are ubiquitous in the environment and originate from a wide range of sources, including the burning of biomass, fossil fuels, and consumer products. Direct evidence for associations between specific VOCs and ischemic heart disease (IHD) mortality in the general population is scarce. Methods: In a case-cohort study (stratified by age groups, sex, residence, and tobacco smoking), nested within the population-based Golestan cohort study (n = 50,045, 40-75 years, 58% women, enrollment: 2004-2008) in northeastern Iran, we measured urinary concentrations of 20 smoking-related VOC biomarkers using ultra high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. We calculated hazard ratio (HR) and 95% confidence interval (CI) for their associations with IHD mortality during follow-up to 2018, using Cox regression models adjusted for age, ethnicity, education, marital status, body mass index, physical activity, wealth, and urinary cotinine. Results: There were 575 non-cases from random subcohort and 601 participants who died from IHD, mean (standard deviation) age, 58.2 (9.3) years, with a median of 8.4 years follow-up. Significant associations [3rd vs. 1st tertile, HR (95% CI), P for trend] were observed between biomarkers of acrylamide [1.68(1.05,2.69), 0.025], acrylonitrile [2.06(1.14,3.72), 0.058], acrolein [1.98(1.30,3.01), 0.003 and 2.44(1.43,4.18), 0.002], styrene/ethylbenzene [1.83(1.19,2.84), 0.007 and 1.44(1.01,2.07), 0.046], dimethylformamide/methylisocyanate [2.15(1.33,3.50), 0.001], and 1,3butadiene [2.35(1.52,3.63),<0.001] and IHD mortality. These associations were independent of tobacco smoking, and they were only present in the non-smoking subgroup. Conclusion: Our findings provide direct evidence for associations between exposure to several VOCs with widespread household and commercial use and IHD mortality many years after these exposures. These results highlight the importance of VOC exposure in the general population as a risk factor for cardiovascular diseases and underline the importance of bio-monitoring non-tobacco VOC exposure.

Effectiveness and predictors of weight loss response to phentermine plus lifestyle modifications among youth in a paediatric weight management clinical setting.

BACKGROUND: Anti-obesity medications (AOMs) are promising lifestyle modification (LSM) adjuncts for obesity treatment, and phentermine is commonly prescribed in paediatric weight management clinics. Determining 'real-world' AOM effectiveness and characteristics predicting response is important. OBJECTIVES: We sought to describe phentermine plus LSM effectiveness and identify baseline characteristics predicting response. METHODS: This was a retrospective cohort study among youth seen in a US academic-based weight management clinic from 2012 to 2020. Baseline characteristics (e.g., body mass index (BMI), liver transaminases, eating-related behaviours) and outcomes (%BMI of 95th percentile (%BMIp95), BMI, %BMI change, weight) were determined through electronic health records and intake surveys. RESULTS: Among 91 youth prescribed phentermine plus LSM over 8 years (mean %BMIp95 150%), %BMIp95 was statistically significantly reduced at 1.5, 3, 6 and 12 months (peak reduction 10.9 percentage points at 6 months; p < 0.001). Considering multiple comparisons, the presence of baseline elevated alanine aminotransferase was associated with statistically significant smaller 1.5-month %BMIp95 reductions (p = 0.001) and higher food responsiveness with smaller 3- (p = 0.001) and 6-month (p < 0.001) reductions. CONCLUSIONS: Phentermine plus LSM reduced %BMIp95 among youth in a weight management clinic, and baseline characteristics may help determine those more or less likely to respond. Prospective studies are needed to further characterize effectiveness and confirm response predictors.

Financial Incentives and Treatment Outcomes in Adolescents With Severe Obesity: A Randomized Clinical Trial.

Importance: Adolescent severe obesity is usually not effectively treated with traditional lifestyle modification therapy. Meal replacement therapy (MRT) shows short-term efficacy for body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) reduction in adolescents, and financial incentives (FIs) may be an appropriate adjunct intervention to enhance long-term efficacy. Objective: To evaluate the effect of MRT plus FIs vs MRT alone on BMI, body fat, and cardiometabolic risk factors in adolescents with severe obesity. Design, Setting, and Participants: This was a randomized clinical trial of MRT plus FIs vs MRT alone at a large academic health center in the Midwest conducted from 2018 to 2022. Participants were adolescents (ages 13-17 y) with severe obesity (≥120% of the 95th BMI percentile based on sex and age or ≥35 BMI, whichever was lower) who were unaware of the FI component of the trial until they were randomized to MRT plus FIs or until the end of the trial. Study staff members collecting clinical measures were blinded to treatment condition. Data were analyzed from March 2022 to February 2024. Interventions: MRT included provision of preportioned, calorie-controlled meals (~1200 kcals/d). In the MRT plus FI group, incentives were provided based on reduction in body weight from baseline. Main Outcomes and Measures: The primary end point was mean BMI percentage change from randomization to 52 weeks. Secondary end points included total body fat and cardiometabolic risk factors: blood pressure, triglyceride to high-density lipoprotein ratio, heart rate variability, and arterial stiffness. Cost-effectiveness was additionally evaluated. Safety was assessed through monthly adverse event monitoring and frequent assessment of unhealthy weight-control behaviors. Results: Among 126 adolescents with severe obesity (73 female [57.9%]; mean [SD] age, 15.3 [1.2] years), 63 participants received MRT plus FIs and 63 participants received only MRT. At 52 weeks, the mean BMI reduction was greater by -5.9 percentage points (95% CI, -9.9 to -1.9 percentage points; P = .004) in the MRT plus FI compared with the MRT group. The MRT plus FI group had a greater reduction in mean total body fat mass by -4.8 kg (95% CI, -9.1 to -0.6 kg; P = .03) and was cost-effective (incremental cost-effectiveness ratio, $39 178 per quality-adjusted life year) compared with MRT alone. There were no significant differences in cardiometabolic risk factors or unhealthy weight-control behaviors between groups. Conclusions and Relevance: In this study, adding FIs to MRT resulted in greater reductions in BMI and total body fat in adolescents with severe obesity without increased unhealthy weight-control behaviors. FIs were cost-effective and possibly promoted adherence to health behaviors. Trial Registration: ClinicalTrials.gov Identifier: NCT03137433.

Clinical effectiveness and predictors of response to topiramate plus lifestyle modification in youth with obesity seen in a weight management clinical setting.

Introduction: Obesity affects approximately 20% of U.S. youth. Anti-obesity medications (AOMs) are promising lifestyle modification adjuncts for obesity treatment, and topiramate is commonly prescribed in pediatric weight management clinics. It is important to determine "real-world" effectiveness of AOMs and, given shifts towards personalized approaches, characteristics potentially predicting better or worse response. We therefore sought to describe clinical effectiveness from topiramate plus lifestyle modification, and to determine if baseline phenotypic characteristics are associated with better or worse response. Methods: We performed a retrospective cohort study (2012-2020) among youth (<18 years old) followed in a U.S. academic-based weight management clinic. Baseline characteristics (i.e., body mass index (BMI), liver function tests, eating-related behaviors) and outcomes (%BMI of 95th percentile (%BMIp95), BMI, percent %BMI change, weight) were determined through review of electronic health records and clinic intake survey data. Results: Among 282 youth prescribed topiramate plus lifestyle modifications (mean baseline age 12.7 years, %BMIp95 144%), %BMIp95 and percent BMI change were statistically significantly reduced at each time point (1.5-, 3-, 6-, and 12-month %BMIp95 reductions: -2.2, -3.9, -6.6, and -9.3 percentage points, respectively; percent BMI reduction: -1.2%, -1.9%, -3.2%, and -3.4%, respectively; all p<0.01). Considering multiple comparisons, no baseline characteristics statistically significantly predicted response at any time point. Conclusions: We found that topiramate plus lifestyle modification reduced %BMIp95 and BMI among youth in a weight management clinical setting, and that no baseline characteristics evaluated were associated with response. These results should be considered preliminary given the observational nature of this study, and prospective studies are needed to further characterize clinical effectiveness and identify and confirm potential predictors of response.

Trabectedin Enhances Oncolytic Virotherapy by Reducing Barriers to Virus Spread and Cytotoxic Immunity in Preclinical Pediatric Bone Sarcoma.

We previously reported that the DNA alkylator and transcriptional-blocking chemotherapeutic agent trabectedin enhances oncolytic herpes simplex viroimmunotherapy in human sarcoma xenograft models, though the mechanism remained to be elucidated. Here we report trabectedin disrupts the intrinsic cellular anti-viral response which increases viral transcript spread throughout the human tumor cells. We also extended our synergy findings to syngeneic murine sarcoma models, which are poorly susceptible to virus infection. In the absence of robust virus replication, we found trabectedin enhanced viroimmunotherapy efficacy by reducing immunosuppressive macrophages and stimulating granzyme expression in infiltrating T and NK cells to cause immune-mediated tumor regressions. Thus, trabectedin enhances both the direct virus-mediated killing of tumor cells and the viral-induced activation of cytotoxic effector lymphocytes to cause tumor regressions across models. Our data provide a strong rationale for clinical translation as both mechanisms should be simultaneously active in human patients.

Evaluating appetite/satiety hormones and eating behaviours as predictors of weight loss maintenance with GLP-1RA therapy in adolescents with severe obesity.

INTRODUCTION: Whilst glucagon-like peptide-1 receptor agonists (GLP1-RAs) are effective for treating adolescent obesity, weight loss maintenance (WLM; preventing weight regain) remains a challenge. Our goal was to investigate appetite/satiety hormones and eating behaviours that may predict WLM with exenatide (a GLP1-RA) versus placebo in adolescents with severe obesity. METHODS: Adolescents who had ≥5% body mass index (BMI) reduction with meal replacement therapy were randomized to 52 weeks of once-weekly exenatide extended release or placebo. In this secondary analysis, eating behaviours and appetite/satiety regulation hormones post-meal replacement therapy (pre-randomization to exenatide or placebo) were evaluated as possible predictors of WLM. Percent change in BMI from randomization to 52 weeks served as the primary measure of WLM. RESULTS: The analysis included 66 adolescents (mean age 16.0 years; 47% female). Lower leptin response to meal testing was associated with greater WLM in terms of BMI percent change in those receiving exenatide compared to placebo (p = 0.007) after adjusting for sex, age and BMI. There were no other significant predictors of WLM. CONCLUSIONS: Prior to exenatide, lower leptin response to meals was associated with improved WLM with exenatide compared to placebo. The mostly null findings of this study suggest that GLP1-RA treatment may produce similar WLM for adolescents with obesity regardless of age, BMI, sex and eating behaviours.

Appetitive and psychological phenotypes of pediatric patients with obesity.

BACKGROUND: Obesity is a heterogeneous disease with variable treatment response. Identification of the unique constellation of contributors to obesity may allow for targeted interventions and improved outcomes. OBJECTIVE: Identify empirically derived phenotypes of pediatric patients with obesity based on appetitive and psychological correlates of obesity. METHODS: This cross-sectional study included patients aged 5-12 years who were treated in a weight management clinic and completed standard intake questionnaires including Child Eating Behavior Questionnaire (CEBQ), Vanderbilt ADHD Scale and Pediatric Symptom Checklist. Phenotypes were elicited using latent profile analysis of 12 indicators: eight CEBQ subscales, inattention, hyperactivity/impulsivity, internalizing and externalizing symptoms. RESULTS: Parents/guardians of 384 patients (mean age 9.8 years, mean BMI 30.3 kg/m2 ) completed the intake questionnaires. A 4-phenotype model best fits the data. Hedonic Impulsive phenotype (42.5%) exhibited high food enjoyment and hyperactivity/impulsivity. Inattentive Impulsive phenotype (27.4%) exhibited overall low food approach and high food avoid behaviours, and highest inattention. Hedonic Emotional phenotype (20.8%) scored the highest on food enjoyment, internalizing and externalizing symptoms. Picky Eating phenotype (9.3%) scored the lowest on food approach, inattention, hyperactivity/impulsivity, internalizing and externalizing symptoms. CONCLUSION: Appetitive traits and psychological symptoms appear to cluster in distinct patterns, giving rise to four unique phenotypic profiles, which, if replicated, may help inform the development of tailored treatment plans.

SMART use of medications for the treatment of adolescent severe obesity: A sequential multiple assignment randomized trial protocol.

BACKGROUND: Severe obesity is a complex, chronic disease affecting nearly 9% of adolescents in the U.S. Although the current mainstay of treatment is lifestyle therapy, pediatric clinical practice guidelines recommend the addition of adjunct anti-obesity medication (AOM), such as phentermine and topiramate. However, guidance regarding when adjunct AOM should be started and how AOM should be used is unclear. Furthermore, an inherent limitation of current treatment guidelines is their "one-size-fits-all" approach, which does not account for the heterogeneous nature of obesity and high degree of patient variability in response to all interventions. METHODS: This paper describes the study design and methods of a sequential multiple assignment randomized trial (SMART), "SMART Use of Medications for the Treatment of Adolescent Severe Obesity." The trial will examine 1) when to start AOM (specifically phentermine) in adolescents who are not responding to lifestyle therapy and 2) how to modify AOM when there is a sub-optimal response to the initial pharmacological intervention (specifically, for phentermine non-responders, is it better to add topiramate to phentermine or switch to topiramate monotherapy). Critically, participant characteristics that may differentially affect response to treatment will be assessed and evaluated as potential moderators of intervention efficacy. CONCLUSION: Data from this study will be used to inform the development of an adaptive intervention for the treatment of adolescent severe obesity that includes empirically-derived decision rules regarding when and how to use AOM. Future research will test this adaptive intervention against standard "one-size-fits-all" treatments.

Aberrant activation of wound healing programs within the metastatic niche facilitates lung colonization by osteosarcoma cells.

Purpose: Lung metastasis is responsible for nearly all deaths caused by osteosarcoma, the most common pediatric bone tumor. How malignant bone cells coerce the lung microenvironment to support metastatic growth is unclear. This study delineates how osteosarcoma cells educate the lung microenvironment during metastatic progression. Experimental design: Using single-cell transcriptomics (scRNA-seq), we characterized genome- and tissue-wide molecular changes induced within lung tissues by disseminated osteosarcoma cells in both immunocompetent murine models of metastasis and patient samples. We confirmed transcriptomic findings at the protein level and determined spatial relationships with multi-parameter immunofluorescence. We evaluated the ability of nintedanib to impair metastatic colonization and prevent osteosarcoma-induced education of the lung microenvironment in both immunocompetent murine osteosarcoma and immunodeficient human xenograft models. Results: Osteosarcoma cells induced acute alveolar epithelial injury upon lung dissemination. scRNA-seq demonstrated that the surrounding lung stroma adopts a chronic, non-resolving wound-healing phenotype similar to that seen in other models of lung injury. Accordingly, metastasis-associated lung demonstrated marked fibrosis, likely due to the accumulation of pathogenic, pro-fibrotic, partially-differentiated epithelial intermediates. Inhibition of fibrotic pathways with nintedanib prevented metastatic progression in multiple murine and human xenograft models. Conclusions: Our work demonstrates that osteosarcoma cells co-opt fibrosis to promote metastatic outgrowth. When harmonized with data from adult epithelial cancers, our results support a generalized model wherein aberrant mesenchymal-epithelial interactions are critical for promoting lung metastasis. Adult epithelial carcinomas induce fibrotic pathways in normal lung fibroblasts, whereas osteosarcoma, a pediatric mesenchymal tumor, exhibits fibrotic reprogramming in response to the aberrant wound-healing behaviors of an otherwise normal lung epithelium, which are induced by tumor cell interactions. Statement of translational relevance: Therapies that block metastasis have the potential to save the majority of lives lost due to solid tumors. Disseminated tumor cells must educate the foreign, inhospitable microenvironments they encounter within secondary organs to facilitate metastatic colonization. Our study elucidated that disseminated osteosarcoma cells survive within the lung by co-opting and amplifying the lung's endogenous wound healing response program. More broadly, our results support a model wherein mesenchymal-epithelial cooperation is a key driver of lung metastasis. Osteosarcoma, a pediatric mesenchymal tumor, undergoes lung epithelial induced fibrotic activation while also transforming normal lung epithelial cells towards a fibrosis promoting phenotype. Conversely, adult epithelial carcinomas activate fibrotic signaling in normal lung mesenchymal fibroblasts. Our data implicates fibrosis and abnormal wound healing as key drivers of lung metastasis across multiple tumor types that can be targeted therapeutically to disrupt metastasis progression.

Host-derived growth factors drive ERK phosphorylation and MCL1 expression to promote osteosarcoma cell survival during metastatic lung colonization.

PURPOSE: For patients with osteosarcoma, disease-related mortality most often results from lung metastasis-a phenomenon shared with many solid tumors. While established metastatic lesions behave aggressively, very few of the tumor cells that reach the lung will survive. By identifying mechanisms that facilitate survival of disseminated tumor cells, we can develop therapeutic strategies that prevent and treat metastasis. METHODS: We analyzed single cell RNA-sequencing (scRNAseq) data from murine metastasis-bearing lungs to interrogate changes in both host and tumor cells during colonization. We used these data to elucidate pathways that become activated in cells that survive dissemination and identify candidate host-derived signals that drive activation. We validated these findings through live cell reporter systems, immunocytochemistry, and fluorescent immunohistochemistry. We then validated the functional relevance of key candidates using pharmacologic inhibition in models of metastatic osteosarcoma. RESULTS: Expression patterns suggest that the MAPK pathway is significantly elevated in early and established metastases. MAPK activity correlates with expression of anti-apoptotic genes, especially MCL1. Niche cells produce growth factors that increase ERK phosphorylation and MCL1 expression in tumor cells. Both early and established metastases are vulnerable to MCL1 inhibition, but not MEK inhibition in vivo. Combining MCL1 inhibition with chemotherapy both prevented colonization and eliminated established metastases in murine models of osteosarcoma. CONCLUSION: Niche-derived growth factors drive MAPK activity and MCL1 expression in osteosarcoma, promoting metastatic colonization. Although later metastases produce less MCL1, they remain dependent on it. MCL1 is a promising target for clinical trials in both human and canine patients.

Trends and Associations of Past-30-Day Cigar Smoking in the U.S. by Age, Race/Ethnicity, and Sex, NSDUH 2002-2020.

Cigar smoking remains a public health issue in the United States (U.S.), with a heterogeneous prevalence based on sociodemographic characteristics. Nationally representative data suggest changes in cigar smoking over time, with some evidence for sociodemographic differences. Using data from the 2002-2019 National Survey on Drug Use and Health (NSDUH), the prevalence of past-30-day cigar smoking was examined overall and stratified by sociodemographic characteristics; joinpoint regression examined the trends. Logistic regression analyses identified the correlates of cigar smoking using 2020 NSDUH data. From 2002 to 2004, the prevalence of cigar smoking remained stable (5.33-5.73%), but declined from 2004 to 2019 (5.73-4.29%). Cigar smoking declined in some periods between 2002-2019 among the non-Hispanic White, Hispanic, ages 12-17, ages 18-20, ages 21-25, age ≥ 35, and male subgroups, but remained unchanged among the non-Hispanic Other, ages 26-34, and female subgroups. Cigar smoking increased among non-Hispanic Black persons overall from 2002 to 2019 (6.67-8.02%). Past-30-day cigarette smoking and drug or alcohol use disorder was associated with an increased likelihood of cigar use, while female sex was associated with a decreased likelihood of cigar use, across all age groups. Though a decline in the prevalence of past-30-day cigar smoking is seen in the general population, the same is not evident among all sociodemographic subgroups. Our findings have the potential to inform tobacco cessation efforts within clinical practice, as well as regulatory efforts to reduce cigar use.

Oncolytic virus-driven immune remodeling revealed in mouse medulloblastomas at single cell resolution.

Oncolytic viruses, modified for tumor-restricted infection, are a promising cancer immunotherapeutic, yet much remains to be understood about factors driving their activity and outcome in the tumor microenvironment. Here, we report that oncolytic herpes simplex virus C134, previously found to exert T cell-dependent efficacy in mouse models of glioblastoma, exerts T cell-independent efficacy in mouse models of medulloblastoma, indicating this oncolytic virus uses different mechanisms in different tumors. We investigated C134's behavior in mouse medulloblastomas, using single cell RNA sequencing to map C134-induced gene expression changes across cell types, timepoints, and medulloblastoma subgroup models at whole-transcriptome resolution. Our work details substantial oncolytic virus-induced transcriptional remodeling of medulloblastoma-infiltrating immune cells, 10 subpopulations of monocytes and macrophages collectively demonstrating M1-like responses to C134, and suggests C134 be investigated as a potential new therapy for medulloblastoma.

Evaluating potential predictors of weight loss response to liraglutide in adolescents with obesity: A post hoc analysis of the randomized, placebo-controlled SCALE Teens trial.

BACKGROUND: As childhood obesity prevalence increases, determining which patients respond to anti-obesity medications would strengthen personalized approaches to obesity treatment. In the SCALE Teens trial among pubertal adolescents with obesity (NCT02918279), liraglutide 3.0 mg (or maximum tolerated dose) significantly reduced body mass index (BMI) standard deviation score on average versus placebo. That said, liraglutide effects on BMI reduction varied greatly among adolescents, similar to adults. OBJECTIVES: To identify post hoc characteristics predictive of achieving ≥5% and ≥10% BMI reductions at 56 weeks with liraglutide versus placebo in adolescents from the SCALE Teens trial. METHODS: Logistic regression analysis was performed in 251 adolescents treated with liraglutide (n = 125) or placebo (n = 126) for 56 weeks. Baseline characteristics (selected a priori) included sex, race, ethnicity, age, Tanner (pubertal) stage, glycemic status (hyperglycemia [type 2 diabetes/prediabetes] vs. normoglycemia), obesity category (Class II/III vs. I), severity of depression symptoms (Patient Health Questionnaire-9), and weight variability (weight fluctuations over time). The effects of early responder status (≥4% BMI reduction at week 16) on week 56 response were assessed using descriptive statistics. RESULTS: Baseline characteristics did not affect achievement of ≥5% and ≥10% BMI reductions at week 56 in adolescents treated with liraglutide. Further, there was no association between weight variability and BMI reduction. Early liraglutide responders appeared to have greater BMI and body weight reductions at week 56 compared with early non-responders. CONCLUSIONS: This secondary analysis suggests that adolescents with obesity may experience significant BMI reductions after 56 weeks of liraglutide treatment, regardless of their sex, race, ethnicity, age, pubertal stage, glycemic status, obesity category, severity of depression symptoms, or weight variability. Early response may predict greater week 56 response.

Structurally Complex Osteosarcoma Genomes Exhibit Limited Heterogeneity within Individual Tumors and across Evolutionary Time.

Osteosarcoma is an aggressive malignancy characterized by high genomic complexity. Identification of few recurrent mutations in protein coding genes suggests that somatic copy-number aberrations (SCNA) are the genetic drivers of disease. Models around genomic instability conflict-it is unclear whether osteosarcomas result from pervasive ongoing clonal evolution with continuous optimization of the fitness landscape or an early catastrophic event followed by stable maintenance of an abnormal genome. We address this question by investigating SCNAs in >12,000 tumor cells obtained from human osteosarcomas using single-cell DNA sequencing, with a degree of precision and accuracy not possible when inferring single-cell states using bulk sequencing. Using the CHISEL algorithm, we inferred allele- and haplotype-specific SCNAs from this whole-genome single-cell DNA sequencing data. Surprisingly, despite extensive structural complexity, these tumors exhibit a high degree of cell-cell homogeneity with little subclonal diversification. Longitudinal analysis of patient samples obtained at distant therapeutic timepoints (diagnosis, relapse) demonstrated remarkable conservation of SCNA profiles over tumor evolution. Phylogenetic analysis suggests that the majority of SCNAs were acquired early in the oncogenic process, with relatively few structure-altering events arising in response to therapy or during adaptation to growth in metastatic tissues. These data further support the emerging hypothesis that early catastrophic events, rather than sustained genomic instability, give rise to structural complexity, which is then preserved over long periods of tumor developmental time. Significance: Chromosomally complex tumors are often described as genomically unstable. However, determining whether complexity arises from remote time-limited events that give rise to structural alterations or a progressive accumulation of structural events in persistently unstable tumors has implications for diagnosis, biomarker assessment, mechanisms of treatment resistance, and represents a conceptual advance in our understanding of intratumoral heterogeneity and tumor evolution.

National longitudinal tobacco product discontinuation rates among US youth from the PATH Study: 2013-2019 (waves 1-5).

OBJECTIVE: Determine longitudinal tobacco product discontinuation rates among youth (ages 12-17 years) in the USA between 2013 and 2019. METHODS: The Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study, was used to determine annual/biennial rates of tobacco product discontinuation behaviours among youth across 2013-2019: (1) discontinuing product use (transition from past 30-day use to no past 30-day use), (2) attempting to quit product use and (3) discontinuing product use among those who attempted to quit. Discontinuing use was evaluated separately for cigarettes, electronic nicotine delivery systems (ENDS), cigars, hookah, smokeless tobacco and any tobacco. Attempting to quit and discontinuing use among those who attempted were each evaluated for cigarettes and ENDS. Generalised estimating equations were used to evaluate linear and non-linear trends in rates across the study period. RESULTS: Between 2013 and 2019, biennial rates of discontinuing tobacco product use among youth increased for cigarettes from 29% to 40%, increased for smokeless tobacco from 39% to 60%, and decreased for ENDS from 53% to 27%. By 2018/2019, rates of discontinuing use among attempters were 30% for those who used ENDS and 30% for those who smoked cigarettes. CONCLUSIONS: Findings show decreasing rates of discontinuing ENDS use among youth in the USA alongside the changing ENDS marketplace and increasing rates of discontinuing cigarette smoking and smokeless tobacco use. Findings will serve as benchmarks against which future tobacco product discontinuation rates can be compared with evaluating impacts of subsequent tobacco regulatory policies, ENDS product development and public education campaigns.

Osteosarcoma tumors maintain intra-tumoral transcriptional heterogeneity during bone and lung colonization.

BACKGROUND: Tumors are complex tissues containing collections of phenotypically diverse malignant and nonmalignant cells. We know little of the mechanisms that govern heterogeneity of tumor cells nor of the role heterogeneity plays in overcoming stresses, such as adaptation to different microenvironments. Osteosarcoma is an ideal model for studying these mechanisms-it exhibits widespread inter- and intra-tumoral heterogeneity, predictable patterns of metastasis, and a lack of clear targetable driver mutations. Understanding the processes that facilitate adaptation to primary and metastatic microenvironments could inform the development of therapeutic targeting strategies. RESULTS: We investigated single-cell RNA-sequencing profiles of 47,977 cells obtained from cell line and patient-derived xenograft models as cells adapted to growth within primary bone and metastatic lung environments. Tumor cells maintained phenotypic heterogeneity as they responded to the selective pressures imposed during bone and lung colonization. Heterogenous subsets of cells defined by distinct transcriptional profiles were maintained within bone- and lung-colonizing tumors, despite high-level selection. One prominent heterogenous feature involving glucose metabolism was clearly validated using immunofluorescence staining. Finally, using concurrent lineage tracing and single-cell transcriptomics, we found that lung colonization enriches for multiple clones with distinct transcriptional profiles that are preserved across cellular generations. CONCLUSIONS: Response to environmental stressors occurs through complex and dynamic phenotypic adaptations. Heterogeneity is maintained, even in conditions that enforce clonal selection. These findings likely reflect the influences of developmental processes promoting diversification of tumor cell subpopulations, which are retained, even in the face of selective pressures.

Single-cell RNA sequencing reveals immunosuppressive myeloid cell diversity during malignant progression in a murine model of glioma.

Recent studies have shown the importance of the dynamic tumor microenvironment (TME) in high-grade gliomas (HGGs). In particular, myeloid cells are known to mediate immunosuppression in glioma; however, it is still unclear if myeloid cells play a role in low-grade glioma (LGG) malignant progression. Here, we investigate the cellular heterogeneity of the TME using single-cell RNA sequencing in a murine glioma model that recapitulates the malignant progression of LGG to HGG. LGGs show increased infiltrating CD4+ and CD8+ T cells and natural killer (NK) cells in the TME, whereas HGGs abrogate this infiltration. Our study identifies distinct macrophage clusters in the TME that show an immune-activated phenotype in LGG but then evolve to an immunosuppressive state in HGG. We identify CD74 and macrophage migration inhibition factor (MIF) as potential targets for these distinct macrophage populations. Targeting these intra-tumoral macrophages in the LGG stage may attenuate their immunosuppressive properties and impair malignant progression.

Opinions from the experts: Experiences of adolescents with severe obesity participating in meal replacement therapy.

BACKGROUND: Meal replacement therapy (MRT) is a structured treatment that is effective for short-term weight reduction in adolescents with severe obesity. However, like other interventions, MRT response is variable. OBJECTIVE: The goal of the current study was to characterize the experience of adolescents with severe obesity participating in MRT. METHODS: Seventeen adolescents with severe obesity participated in semi-structured, individual interviews about their experience participating in MRT. The authors used a biopsychosocial model as the theoretical framework and data was analysed using Interpretive Phenomenological Analysis. A biopsychosocial model views an individual's health as a blend of biological characteristics, behavioural factors, and social conditions. RESULTS: Results showed that adolescents with severe obesity described three biopsychosocial factors that were central to their experience with MRT: (1) scheduling and planning, (2) social support and pressure, and (3) intrapersonal factors. Specifically, adolescents with severe obesity identified that planning ahead, social support, and intrapersonal changes (e.g. self-confidence) can promote engagement in MRT. On the other hand, unplanned schedule changes, social pressures, and different intrapersonal factors (e.g., taste preference) can make engagement challenging. CONCLUSIONS: Adolescents provided information on factors that supported or hindered their engagement in MRT, and themes were consistent with prior literature on health behaviour change. Overall, adolescents would recommend MRT to other teenagers who carry extra weight. Future research can use the rich information provided by adolescents with severe obesity to enhance and individualize treatment options.

National longitudinal tobacco product cessation rates among US adults from the PATH Study: 2013-2019 (waves 1-5).

OBJECTIVE: To report on longitudinal tobacco product cessation rates, by product type, among adults (ages 18+ years) in the USA between 2013 and 2019. METHODS: The Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study was used to report on annual and biennial rates of the following three cessation behaviours across 2013-2019: (1) discontinuing tobacco product use (ie, transition from past 30-day use to no past 30-day use), (2) attempting to quit tobacco product use and (3) quitting tobacco product use among those who attempted to quit. Each cessation behaviour was evaluated separately for cigarettes, electronic nicotine delivery systems (ENDS), cigars, hookah and smokeless tobacco. Generalised estimating equations were used to evaluate linear and nonlinear trends in cessation rates across the study period. RESULTS: Between 2013 and 2019, rates of discontinuing cigarette smoking among adults in the USA statistically increased from 16% to 18%, though these were consistently lower than rates of discontinuing use of other tobacco products. Similarly, quit attempt rates and rates of quitting among attempters increased for cigarette smokers. However, rates of discontinuing ENDS use sharply declined across the study period, from 62% to 44%. CONCLUSIONS: Findings show that tobacco product cessation rates have been changing in recent years in the USA alongside the changing tobacco product marketplace and regulatory environment, though rates of discontinuing cigarette smoking remain relatively low. Findings can serve as a benchmark against which future cessation rates can be compared with evaluate the impacts of future tobacco regulatory policies.

Lurbinectedin Inhibits the EWS-WT1 Transcription Factor in Desmoplastic Small Round Cell Tumor.

Desmoplastic small round cell tumor (DSRCT) is a rare pediatric sarcoma with poor overall survival. This tumor is absolutely dependent on the continued expression and activity of its defining molecular lesion, the EWS-WT1 transcription factor. Unfortunately, the therapeutic targeting of transcription factors is challenging, and there is a critical need to identify compounds that inhibit EWS-WT1. Here we show that the compound lurbinectedin inhibits EWS-WT1 by redistributing the protein within the nucleus to the nucleolus. This nucleolar redistribution interferes with the activity of EWS-WT1 to reverse the expression of over 70% of the transcriptome. In addition, the compound blocks the expression of the EWS-WT1 fusion protein to inhibit cell proliferation at the lowest GI50 ever reported for this compound in any cell type. The effects occur at concentrations that are easily achievable in the clinic and translate to the in vivo setting to cause tumor regressions in multiple mice in a xenograft and PDX model of DSRCT. Importantly, this mechanism of nucleolar redistribution is also seen with wild-type EWSR1 and the related fusion protein EWS-FLI1. This provides evidence for a "class effect" for the more than 18 tumors driven by EWSR1 fusion proteins. More importantly, the data establish lurbinectedin as a promising clinical candidate for DSRCT.