Stephanie Tuminello

Lkb1 inactivation drives lung cancer lineage switching governed by Polycomb Repressive Complex 2

Adenosquamous lung tumours, which are extremely poor prognosis, may result from cellular plasticity. Here, we demonstrate lineage switching of KRAS+ lung adenocarcinomas (ADC) to squamous cell carcinoma (SCC) through deletion of Lkb1 (Stk11) in autochthonous and transplant models. Chromatin analysis reveals loss of H3K27me3 and gain of H3K27ac and H3K4me3 at squamous lineage genes, including Sox2, ΔNp63 and Ngfr. SCC lesions have higher levels of the H3K27 methyltransferase EZH2 than the ADC lesions, but there is a clear lack of the essential Polycomb Repressive Complex 2 (PRC2) subunit EED in the SCC lesions. The pattern of high EZH2, but low H3K27me3 mark, is also prevalent in human lung SCC and SCC regions within ADSCC tumours. Using FACS-isolated populations, we demonstrate that bronchioalveolar stem cells and club cells are the likely cells-of-origin for SCC transitioned tumours. These findings shed light on the epigenetics and cellular origins of lineage-specific lung tumours.

Preliminary Assessment of Hurricane Harvey Exposures and Mental Health Impact

Hurricane Harvey made landfall in Houston, Texas on 25 August 2017, the psychological and physical effects of which are still unknown. We assessed hurricane exposure and the immediate mental health needs of the population to define public health priorities for a larger epidemiological study. Convenience sampling was used to recruit participants (n = 41) from the greater Houston area aged ≥18 years. Participants completed a questionnaire about demographics, hurricane exposures, and physical/mental health. Post-Traumatic Stress Disorder (PTSD) was measured with the Post-Traumatic Stress Disorder Checklist-S (PCL-S; a score ≥30 indicated probable PTSD symptoms). The Patient Health Questionnaire-4 (PHQ-4) was used to assess symptoms of depression and generalized anxiety disorder. The average PTSD score was 32.9 (SD = 17.1); a total of 46% of participants met the threshold for probable PTSD. Increased overall hurricane exposure (adjusted odds ratio (ORadj) 1.42; 95% confidence interval (CI): 1.06–2.05) and property-related exposure (ORadj 1.53; 95% CI: 1.07–2.18) were both statistically significantly associated with increased odds of probable PTSD symptoms. A perception of chemical/toxin exposure due to Hurricane Harvey was reported by 44% of participants. A higher number of personal or property exposures were associated with greater mental health symptoms three weeks post-hurricane. This work has implications for the ongoing response to Hurricane Harvey and for assessing the immediate needs of the population.

Regulatory architecture of the LβT2 gonadotrope cell underlying the response to gonadotropin-releasing hormone

The LβT2 mouse pituitary cell line has many characteristics of a mature gonadotrope and is a widely used model system for studying the developmental processes and the response to gonadotropin-releasing hormone (GnRH). The global epigenetic landscape, which contributes to cell-specific gene regulatory mechanisms, and the single-cell transcriptome response variation of LβT2 cells have not been previously investigated. Here, we integrate the transcriptome and genome-wide chromatin accessibility state of LβT2 cells during GnRH stimulation. In addition, we examine cell-to-cell variability in the transcriptional response to GnRH using Gel bead-in-Emulsion Drop-seq technology. Analysis of a bulk RNA-seq data set obtained 45 min after exposure to either GnRH or vehicle identified 112 transcripts that were regulated >4-fold by GnRH (FDR < 0.05). The top regulated transcripts constitute, as determined by Bayesian massive public data integration analysis, a human pituitary-relevant coordinated gene program. Chromatin accessibility [assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq)] data sets generated from GnRH-treated LβT2 cells identified more than 58,000 open chromatin regions, some containing notches consistent with bound transcription factor footprints. The study of the most prominent open regions showed that 75% were in transcriptionally active promoters or introns, supporting their involvement in active transcription. Lhb, Cga, and Egr1 showed significantly open chromatin over their promoters. While Fshb was closed over its promoter, several discrete significantly open regions were found at −40 to −90 kb, which may represent novel upstream enhancers. Chromatin accessibility determined by ATAC-seq was associated with high levels of gene expression determined by RNA-seq. We obtained high-quality single-cell Gel bead-in-Emulsion Drop-seq transcriptome data, with an average of >4,000 expressed genes/cell, from 1,992 vehicle- and 1,889 GnRH-treated cells. While the individual cell expression patterns showed high cell-to-cell variation, representing both biological and measurement variation, the average expression patterns correlated well with bulk RNA-seq data. Computational assignment of each cell to its precise cell cycle phase showed that the response to GnRH was unaffected by cell cycle. To our knowledge, this study represents the first genome-wide epigenetic and single-cell transcriptomic characterization of this important gonadotrope model. The data have been deposited publicly and should provide a resource for hypothesis generation and further study.

Mental health challenges and experiences in displaced populations following Hurricane Sandy and Hurricane Harvey: the need for more comprehensive interventions in temporary shelters

Hurricane exposure can have a profound impact on mental health, leading to increased symptoms of stress, anxiety, depression and post-traumatic stress disorder that are still present years after the storm. Those displaced following a hurricane are particularly vulnerable to adverse mental health outcomes, especially if displaced to temporary shelters. The current work highlights the experiences and mental health challenges of displaced populations following Hurricane Sandy and Hurricane Harvey, as well as describing barriers to conducting research in the immediate aftermath of Hurricane Harvey and the need for more comprehensive interventions in these vulnerable populations.

Opioid Use After Open Resection or Video-Assisted Thoracoscopic Surgery for Early-Stage Lung Cancer

Discussion | The observation of common and durable response to targeted therapy and immunotherapy has raised questions about whether traditional randomized trials are necessary to support drug approval.6 The ability to study a drug’s ORR, especially in clearly defined target populations, makes the singlearm study design appealing as a pathway to approval. The ability to identify target populations has been aided by increasing understanding of the molecular basis of cancer, which has allowed anatomically defined cancers to be subdivided into smaller, molecularly defined subtypes more likely to respond to targeted therapies. Our data confirm that ORR is a common end point in single-arm studies supporting accelerated approval of anticancer therapies. However, a small proportion of single-arm studies met the threshold for substantial clinical benefit defined by ESMO-MCBS, version 1.1. These results are unsurprising because, to meet substantial benefit thresholds using the ESMO-MCBS, a single-arm trial must show substantial efficacy as well as improvement in quality of life or have data from confirmatory postmarketing study. The low proportion of single-arm trials that meet the threshold for substantial benefit may reflect a lack of supporting data or unrealistic thresholds in the ESMO framework. In conclusion, approximately one-third of trials supporting FDA drug approval meet the threshold for substantial clinical benefit as measured by ESMO-MCBS. Compared with RCTs, approvals supported by single-arm studies are less likely to show substantial benefit using ESMO-MCBS. It is likely that this reflects the high thresholds for substantial benefit used to calibrate the ESMO-MCBS for single-arm trials.