Nitric oxide could promote development of Barrett's esophagus by S-nitrosylation-induced inhibition of Rho-ROCK signaling in esophageal fibroblasts

Long-term exposure to air pollution and esophageal cancer incidence: A large-scale prospective cohort study

BACKGROUND

Epidemiological evidence regarding the association between long-term air pollution exposures and esophageal cancer is limited and controversial. This study aims to investigate this association further and assess its impact on different histological subtypes of esophageal cancer.

METHODS

Data from the UK Biobank cohort, which included 444,932 participants, was utilized for this study. High-resolution 1 × 1 km data from the UK's Department for Environment, Food and Rural Affairs was used to estimate annual concentrations of air pollutants based on participants' residential addresses. The Time-Dependent Cox proportional hazard model was employed to estimate the hazard ratios (HRs) and 95 % confidence intervals (CIs) for the incidence of esophageal cancer associated with air pollutant exposure.

RESULT

Over a follow-up duration of 4,777,149 person-years, 1008 new esophageal cancer cases were observed. No association between PM2.5 and PM10 exposure and esophageal cancer was found. However, long-term exposure to NO2, NOx, SO2 and benzene demonstrated a linear relationship with the risk of esophageal cancer incidence. The HRs were 1.278 (95 % CI: 1.104-1.480) per 10 μg/m3 for NO2, 1.129 (95 % CI: 1.046-1.218) per 10 μg/m3 for NOx, 1.109 (95 % CI: 1.041-1.182) per 1 μg/m3 for SO2 and 1.086 (95 % CI: 1.010-1.167) per 0.1 μg/m3 for benzene, respectively. No statistically significant heterogeneity was detected between the histological subtypes of squamous cell carcinoma and adenocarcinoma. Elderly individuals were more vulnerable to nitrogen oxides, while smokers or former smokers were more susceptible to the effects of sulfur dioxide.

CONCLUSION

Long-term exposure to air pollutants may significantly increase the risk of esophageal cancer. Effective and targeted control of ambient air pollutant concentrations could potentially reduce the disease burden of esophageal cancer.

Metabolic reprogramming and immunological changes in the microenvironment of esophageal cancer: future directions and prospects

Background

Esophageal cancer (EC) is the seventh-most prevalent cancer worldwide and is a significant contributor to cancer-related mortality. Metabolic reprogramming in tumors frequently coincides with aberrant immune function alterations, and extensive research has demonstrated that perturbations in energy metabolism within the tumor microenvironment influence the occurrence and progression of esophageal cancer. Current treatment modalities for esophageal cancer primarily include encompass chemotherapy and a limited array of targeted therapies, which are hampered by toxicity and drug resistance issues. Immunotherapy, particularly immune checkpoint inhibitors (ICIs) targeting the PD-1/PD-L1 pathway, has exhibited promising results; however, a substantial proportion of patients remain unresponsive. The optimization of these immunotherapies requires further investigation. Mounting evidence underscores the importance of modulating metabolic traits within the tumor microenvironment (TME) to augment anti-tumor immunotherapy.

Methods

We selected relevant studies on the metabolism of the esophageal cancer tumor microenvironment and immune cells based on our searches of MEDLINE and PubMed, focusing on screening experimental articles and reviews related to glucose metabolism, amino acid metabolism, and lipid metabolism, as well their interactions with tumor cells and immune cells, published within the last five years. We analyzed and discussed these studies, while also expressing our own insights and opinions.

Results

A total of 137 articles were included in the review: 21 articles focused on the tumor microenvironment of esophageal cancer, 33 delved into research related to glucose metabolism and tumor immunology, 30 introduced amino acid metabolism and immune responses, and 17 focused on the relationship between lipid metabolism in the tumor microenvironment and both tumor cells and immune cells.

Conclusion

This article delves into metabolic reprogramming and immune alterations within the TME of EC, systematically synthesizes the metabolic characteristics of the TME, dissects the interactions between tumor and immune cells, and consolidates and harnesses pertinent immunotherapy targets, with the goal of enhancing anti-tumor immunotherapy for esophageal cancer and thereby offering insights into the development of novel therapeutic strategies.

Redox regulation, protein S-nitrosylation, and synapse loss in Alzheimer's and related dementias

Redox-mediated posttranslational modification, as exemplified by protein S-nitrosylation, modulates protein activity and function in both health and disease. Here, we review recent findings that show how normal aging, infection/inflammation, trauma, environmental toxins, and diseases associated with protein aggregation can each trigger excessive nitrosative stress, resulting in aberrant protein S-nitrosylation and hence dysfunctional protein networks. These redox reactions contribute to the etiology of multiple neurodegenerative disorders as well as systemic diseases. In the CNS, aberrant S-nitrosylation reactions of single proteins or, in many cases, interconnected networks of proteins lead to dysfunctional pathways affecting endoplasmic reticulum (ER) stress, inflammatory signaling, autophagy/mitophagy, the ubiquitin-proteasome system, transcriptional and enzymatic machinery, and mitochondrial metabolism. Aberrant protein S-nitrosylation and transnitrosylation (transfer of nitric oxide [NO]-related species from one protein to another) trigger protein aggregation, neuronal bioenergetic compromise, and microglial phagocytosis, all of which contribute to the synapse loss that underlies cognitive decline in Alzheimer's disease and related dementias.

The role of the fibroblast in Barrett's esophagus and esophageal adenocarcinoma

PURPOSE OF REVIEW

Barrett's esophagus (BE) is the number one risk factor for developing esophageal adenocarcinoma (EAC), a deadly cancer with limited treatment options that has been increasing in incidence in the US. In this report, we discuss current studies on the role of mesenchyme and cancer-associated fibroblasts (CAFs) in BE and EAC, and we highlight translational prospects of targeting these cells.

RECENT FINDINGS

New insights through studies using single-cell RNA sequencing (sc-RNA seq) have revealed an important emerging role of the mesenchyme in developmental signaling and cancer initiation. BE and EAC share similar stromal gene expression, as functional classifications of nonepithelial cells in BE show a remarkable similarity to EAC CAFs. Several recent sc-RNA seq studies and novel organoid fibroblast co-culture systems have characterized the subgroups of fibroblasts in BE and EAC, and have shown that these cells can directly influence the epithelium to induce BE development and cancer progression. Targeting the CAFs in EAC with may be a promising novel therapeutic strategy.

SUMMARY

The fibroblasts in the surrounding mesenchyme may have a direct role in influencing altered epithelial plasticity during BE development and progression to EAC.

Cancer-Associated Fibroblasts in Esophageal Cancer

Cancer-associated fibroblasts (CAFs), a heterogenous population, can promote cancer cell proliferation, migration, invasion, immunosuppression, and therapeutic resistance in solid tumors. These effects are mediated through secretion of cytokines and growth factors, remodeling of the extracellular matrix, and providing metabolic support for cancer cells. The presence of CAFs in esophageal carcinoma are associated with reduced overall survival and increased resistance to chemotherapy and radiotherapy; thus, identifying therapeutic vulnerabilities of CAFs is a necessity. In esophageal cancer, the mechanisms for CAF recruitment, CAF-mediated promotion of tumorigenesis, metastatic dissemination, and therapeutic resistance have yet to be fully evaluated. Here, we provide an overview of the current understanding of CAFs in esophageal cancer, namely in esophageal squamous cell carcinoma and esophageal adenocarcinoma, as well as in the preneoplastic conditions that predispose to these cancers. Interestingly, there is a discrepancy in our knowledge of CAF biology between esophageal cancer subtypes, with very few studies in esophageal adenocarcinoma, and its precursor lesion Barrett's esophagus, compared with esophageal squamous cell carcinoma. We propose that although great strides have been made, certain questions remain to which answers hopefully will emerge to have an impact on biomarker diagnostics and translational therapeutics.

Tumour microenvironment influences response to treatment in oesophageal adenocarcinoma

The poor treatment response of oesophageal adenocarcinoma (OAC) leads to low survival rates. Its increasing incidence makes finding more effective treatment a priority. Recent treatment improvements can be attributed to the inclusion of the tumour microenvironment (TME) and immune infiltrates in treatment decisions. OAC TME is largely immunosuppressed and reflects treatment resistance as patients with inflamed TME have better outcomes. Priming the tumour with the appropriate neoadjuvant chemoradiotherapy treatment could lead to higher immune infiltrations and higher expression of immune checkpoints, such as PD-1/PDL-1, CTLA4 or emerging new targets: LAG-3, TIM-3, TIGIT or ICOS. Multiple trials support the addition of immune checkpoint inhibitors to the current standard of care. However, results vary, supporting the need for better response biomarkers based on TME composition. This review explores what is known about OAC TME, the clinical significance of the various cell populations infiltrating it and the emerging therapeutical combination with a focus on immune checkpoints inhibitors.