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Contains fulltext : 291567.pdf (Publisher’s version ) (Open Access) The aryl hydrocarbon receptor (AHR) is a sensor of low-molecular-weight molecule signals that originate from environmental exposures, the microbiome, and host metabolism. Building upon initial studies examining anthropogenic chemical exposures, the list of AHR ligands of microbial, diet, and host metabolism origin continues to grow and has provided important clues as to the function of this enigmatic receptor. The AHR has now been shown to be directly involved in numerous biochemical pathways that influence host homeostasis, chronic disease development, and responses to toxic insults. As this field of study has continued to grow, it has become apparent that the AHR is an important novel target for cancer, metabolic diseases, skin conditions, and autoimmune disease. This meeting attempted to cover the scope of basic and applied research being performed to address possible applications of our basic knowledge of this receptor on therapeutic outcomes.

For decades, the aryl hydrocarbon receptor (AHR) was studied for its role in environmental chemical toxicity i.e., as a quirk of nature and a mediator of unintended consequences of human pollution. During that period, it was not certain that the AHR had a “normal” physiological function. However, the ongoing accumulation of data from an ever-expanding variety of studies on cancer, cancer immunity, autoimmunity, organ development, and other areas bears witness to a staggering array of AHR-controlled normal and pathological activities. The objective of this review is to discuss how the AHR has gone from a likely contributor to genotoxic environmental carcinogen-induced cancer to a master regulator of malignant cell progression and cancer aggression. Particular focus is placed on the association between AHR activity and poor cancer outcomes, feedback loops that control chronic AHR activity in cancer, and the role of chronically active AHR in driving cancer cell invasion, migration, cancer stem cell characteristics, and survival.

Significance Immune checkpoint inhibitors have emerged as critical therapeutics for several cancer types, including head and neck squamous cell carcinoma. However, enthusiasm remains constrained by the fact that only a minority of patients benefit. Therefore, there is a need to identify new immunotherapy targets. Here, we provide evidence supporting our hypothesis that the aryl hydrocarbon receptor (AhR) influences multiple immune checkpoints in a model of oral squamous cell carcinoma (OSCC). Remarkably, transplant of AhR-deleted OSCC cells generates completely protective tumor immunity characterized by a decrease in multiple immune checkpoints (PD-L1, CD39, CTLA4, PD1, and Lag3) on malignant and/or immune cells. These results have important implications for understanding the biology of cancer immunosuppression and for targeting the AhR for cancer immunotherapy., Immune checkpoint inhibitors represent some of the most important cancer treatments developed in the last 20 y. However, existing immunotherapy approaches benefit only a minority of patients. Here, we provide evidence that the aryl hydrocarbon receptor (AhR) is a central player in the regulation of multiple immune checkpoints in oral squamous cell carcinoma (OSCC). Orthotopic transplant of mouse OSCC cells from which the AhR has been deleted (MOC1AhR-KO) results, within 1 wk, in the growth of small tumors that are then completely rejected within 2 wk, concomitant with an increase in activated T cells in tumor-draining lymph nodes (tdLNs) and T cell signaling within the tumor. By 2 wk, AhR+ control cells (MOC1Cas9), but not MOC1AhR-KO cells up-regulate exhaustion pathways in the tumor-infiltrating T cells and expression of checkpoint molecules on CD4+ T cells (PD-1, CTLA4, Lag3, and CD39) and macrophages, dendritic cells, and Ly6G+ myeloid cells (PD-L1 and CD39) in tdLNs. Notably, MOC1AhR-KO cell transplant renders mice 100% immune to later challenge with wild-type tumors. Analysis of altered signaling pathways within MOC1AhR-KO cells shows that the AhR controls baseline and IFNγ-induced Ido and PD-L1 expression, the latter of which occurs through direct transcriptional control. These observations 1) confirm the importance of malignant cell AhR in suppression of tumor immunity, 2) demonstrate the involvement of the AhR in IFNγ control of PD-L1 and IDO expression in the cancer context, and 3) suggest that the AhR is a viable target for modulation of multiple immune checkpoints.

Objective:To understand how routine bedside clinical neurologic assessments are performed in U.S. PICUs.Design:Electronic survey.Setting:Academic PICUs throughout the United States.Subjects:Faculty representatives from PICUs throughout the United States.Interventions:None.Measurements and Main Resul

OBJECTIVES To evaluate if the use of apneic oxygenation during tracheal intubation in children is feasible and would decrease the occurrence of oxygen desaturation. DESIGN Prospective pre/post observational study. SETTING A large single-center noncardiac PICU in North America. PATIENTS All patients less than 18 years old who underwent primary tracheal intubation from August 1, 2014, to September 30, 2018. INTERVENTIONS Implementation of apneic oxygenation for all primary tracheal intubation as quality improvement. MEASUREMENTS AND MAIN RESULTS Total of 1,373 tracheal intubations (661 preimplementation and 712 postimplementation) took place during study period. Within 2 months, apneic oxygenation use reached to predefined adherence threshold (> 80% of primary tracheal intubations) after implementation and sustained at greater than 70% level throughout the postimplementation. Between the preimplementation and postimplementation, no significant differences were observed in patient demographics, difficult airway features, or providers. Respiratory and procedural indications were more common during preintervention. Video laryngoscopy devices were used more often during the postimplementation (pre 5% vs post 75%; p < 0.001). Moderate oxygen desaturation less than 80% were observed in fewer tracheal intubations after apneic oxygenation implementation (pre 15.4% vs post 11.8%; p = 0.049); severe oxygen desaturation less than 70% was also observed in fewer tracheal intubations after implementation (pre 10.4% vs post 7.2%; p = 0.032). Hemodynamic tracheal intubation associated events (i.e., cardiac arrests, hypotension, dysrhythmia) were unchanged (pre 3.2% vs post 2.0%; p = 0.155). Multivariable analyses showed apneic oxygenation implementation was significantly associated with a decrease in moderate desaturation less than 80% (adjusted odds ratio, 0.55; 95% CI, 0.34-0.88) and with severe desaturation less than 70% (adjusted odds ratio, 0.54; 95% CI, 0.31-0.96) while adjusting for tracheal intubation indications and device. CONCLUSIONS Implementation of apneic oxygenation in PICU was feasible, and was associated with significant reduction in moderate and severe oxygen desaturation. Use of apneic oxygenation should be considered when intubating critically ill children.