The immunophenotypic relationship between the submucosal gland unit, columnar metaplasia and squamous islands in the columnar-lined oesophagus

Cellular Origins and Lineage Plasticity in Cancer

All cancers arise from normal cells whose progeny acquire the cancer-initiating mutations and epigenetic modifications leading to frank tumorigenesis. The identity of those "cells-of-origin" has historically been a source of controversy across tumor types, as it has not been possible to witness the dynamic events giving rise to human tumors. Genetically engineered mouse models (GEMMs) of cancer provide an invaluable substitute, enabling researchers to interrogate the competence of various naive cellular compartments to initiate tumors in vivo. Researchers using these models have relied on lineage-specific promoters, knowledge of preneoplastic disease states in humans, and technical advances allowing more precise manipulations of the mouse germline. These approaches have given rise to the emerging view that multiple lineages within a given organ may generate tumors with similar histopathology. Here, we review some of the key studies leading to this conclusion in solid tumors and highlight the biological and clinical ramifications.

Single cell RNA-seq reveals profound transcriptional similarity between Barrett's oesophagus and oesophageal submucosal glands

Barrett's oesophagus is a precursor of oesophageal adenocarcinoma. In this common condition, squamous epithelium in the oesophagus is replaced by columnar epithelium in response to acid reflux. Barrett's oesophagus is highly heterogeneous and its relationships to normal tissues are unclear. Here we investigate the cellular complexity of Barrett's oesophagus and the upper gastrointestinal tract using RNA-sequencing of single cells from multiple biopsies from six patients with Barrett's oesophagus and two patients without oesophageal pathology. We find that cell populations in Barrett's oesophagus, marked by LEFTY1 and OLFM4, exhibit a profound transcriptional overlap with oesophageal submucosal gland cells, but not with gastric or duodenal cells. Additionally, SPINK4 and ITLN1 mark cells that precede morphologically identifiable goblet cells in colon and Barrett's oesophagus, potentially aiding the identification of metaplasia. Our findings reveal striking transcriptional relationships between normal tissue populations and cells in a premalignant condition, with implications for clinical practice.

Effects of estrogen on esophageal function through regulation of Ca2+-related proteins

BACKGROUND

The calcium ion is important for physiological functions in all tissues and organs and essential to many vital functions, including hormone secretion and muscle contraction. The intracellular concentration of calcium is regulated by calcium related proteins such as CaBP-9k, PMCA1, and NCX1. In this study, we investigated the relationship between calcium regulation and esophageal functions such as mucin secretion and smooth muscle contraction.

METHODS

To evaluate the influence of sex steroid hormones, immature rats were treated for 3 days with estradiol (E2), progesterone (P4), and their antagonists (ICI 182,780, and RU486). Esophageal function, transcription level, and localization of CaBP-9k, PMCA1, NCX1, ERα, and MUC2 were examined in the esophagus.

RESULTS

Transcriptional level of Cabp-9k and Muc2 was increased by E2, but not by P4. CaBP-9k, PMCA1, and MUC2 were mainly localized in the mucosal layer. Acidic mucosubstances in the esophagus were increased by E2 and recovered by ICI treatment. Unlike the expression of Cabp-9k, mRNA levels of Pmca1, Ncx1, and Erα were only decreased in response to E2, and recovered by ICI co-treatment group. The contraction of the esophagus and mRNA level of Mylk were reduced by E2. Overall, E2 upregulated mucus secretion, but downregulated muscle contraction in the esophagus through regulation of the expression of calcium related genes and the resultant intracellular calcium level.

CONCLUSIONS

The regulation of E2 in the function of esophagus may be applied to treat esophageal diseases such as reflux esophagitis, achalasia, and esophageal cancer.