Spasmolytic polypeptide-expressing metaplasia (SPEM) in the gastric oxyntic mucosa does not arise from Lgr5-expressing cells.

OBJECTIVE: Metaplastic lineages in the oxyntic mucosa of the stomach are critical preneoplastic precursors of gastric cancer. Recent studies have demonstrated that spasmolytic polypeptide-expressing metaplasia (SPEM) in the mouse oxyntic mucosa arises from transdifferentiation of mature gastric chief cells. Other investigations of intestinal progenitor cells have shown that cells demonstrating transcriptional activity for leucine-rich repeat containing G-protein-coupled receptor 5 (Lgr5) in the intestine, colon and gastric antrum function as adult stem cells. We have now investigated whether cells demonstrating Lgr5 transcriptional activity in the oxyntic mucosa of mice might be responsible for development of metaplasia. DESIGN: Lgr5-EGFP-IRES-Cre(ERT2/+);Rosa26R mice were used to examine the distribution of Lgr5 transcriptionally active cells in the normal oxyntic mucosa as well as after treatment with DMP-777 or L-635 to induce acute SPEM. Lineage mapping was performed to determine if Lgr5-expressing cells gave rise to SPEM. RESULTS: Cells expressing transcriptional activity for Lgr5 in the oxyntic mucosa were present as scattered rare cells only along the lesser curvature of the stomach. These cells also stained for markers of chief cells (intrinsic factor and pepsinogen) but never showed any staining for proliferative markers (Ki-67). In Lgr5-EGFP-IRES-Cre(ERT2/+);Rosa26R mice induced with tamoxifen, treatment with either DMP-777 or L-635 to induce acute oxyntic atrophy caused induction of SPEM, but no lineage mapping into SPEM from Lgr5-expressing cells was observed. CONCLUSION: The results indicate that, while chief cells with Lgr5 transcriptional activity are present along the lesser curvature of the gastric oxyntic mucosa, they are not responsible for production of metaplasia.

Mature chief cells are cryptic progenitors for metaplasia in the stomach.

BACKGROUND & AIMS: Gastric cancer evolves in the setting of a pathologic mucosal milieu characterized by both loss of acid-secreting parietal cells and mucous cell metaplasias. Indeed, mucous cell metaplasia is considered the critical preneoplastic lesion for gastric cancer. Previous investigations have shown that infection of mice with Helicobacter felis or induction of acute parietal cell loss with the drug DMP-777 leads to the emergence of a type of metaplasia designated spasmolytic polypeptide-expressing metaplasia (SPEM). We have hypothesized that SPEM arises from proliferating cells in gland bases, either from a cryptic progenitor cell or by transdifferentiation of mature chief cells. METHODS: Taking advantage of the chief cell-restricted expression of Mist1-Cre-ER(T2), we used lineage mapping to examine whether SPEM lineages were derived from chief cells in 3 independent models of induction by DMP-777 treatment, L-635 treatment, or H felis infection. RESULTS: Treatment of mice with L-635 for 3 days led to rapid parietal cell loss, induction of a prominent inflammatory infiltrate, and emergence of SPEM. In all 3 models, SPEM developed, at least in part, from transdifferentiation of chief cells. We further found that acute parietal cell loss in the setting of inflammation (L-635 treatment) led to more rapid induction and expansion of SPEM derived from transdifferentiation of chief cells. CONCLUSIONS: These studies provide direct evidence by lineage tracing that SPEM evolves from differentiated chief cells. Thus, mature gastric chief cells have the ability to act as cryptic progenitors and reacquire proliferative capacity within the context of mucosal injury and inflammation.

Human epididymis protein 4 is up-regulated in gastric and pancreatic adenocarcinomas.

Upper gastrointestinal neoplasia in the esophagus, stomach, and pancreas is associated with the formation of preneoplastic metaplasias. We have previously reported the up-regulation of human epididymis protein 4 (HE4) in all metaplasias in the stomach of humans and mice. We have now sought to evaluate the expression of HE4 in metaplasias/preneoplastic precursors and cancers of the human stomach, pancreas, and esophagus. Tissue microarrays for gastric cancers, pancreatic cancers, and esophageal adenocarcinoma were stained with antibodies against HE4. Immunostaining was quantified by digital imaging, and the results were evaluated to assess the expression in metaplasias, the expression in cancer pathological subtypes, and the effects of expression on survival in patients with cancer. In patients with gastric cancer from Korea, HE4 was detected in 74% of intestinal and 90% of diffuse cancers, whereas in a gastric cancer cohort from Johns Hopkins, HE4 was detected in 74% of intestinal-type and 92% of diffuse cancers. Nevertheless, in both cohorts, there was no impact of HE4 expression on overall survival. In the esophagus, we observed the expression of HE4 in scattered endocrine cells within Barrett esophagus samples, but Barrett columnar metaplasias and HE4 were detected in only 2% of esophageal adenocarcinomas. Finally, in the pancreas, HE4 expression was not observed in pancreatic intraepithelial neoplasia lesions, but 46.8% of pancreatic adenocarcinomas expressed HE4. Still, we did not observe any influence of HE4 expression on survival. The results suggest that HE4 is up-regulated during gastric and pancreatic carcinogenesis.