Distribution of LGR5+ Cells and Associated Implications during the Early Stage of Gastric Tumorigenesis

Abstract

Lgr5 was identified as a promising gastrointestinal tract stem cell marker in mice. Lineage tracing indicates that Lgr5 + cells may not only be the cells responsible for the origin of tumors; they may also be the so-called cancer stem cells. In the present study, we investigated the presence of Lgr5 + cells and their biological significance in normal human gastric mucosa and gastric tumors. RNAscope, a newly developed RNA in situ hybridization technique, specifically labeled Lgr5 + cells at the basal glands of the gastric antrum. Notably, the number of Lgr5 + cells was remarkably increased in intestinal metaplasia. In total, 76% of gastric adenomas and 43% of early gastric carcinomas were positive for LGR5. Lgr5 + cells were found more frequently in low-grade tumors with active Wnt signaling and an intestinal gland type, suggesting that LGR5 is likely involved in the very early stages of Wnt-driven tumorigenesis in the stomach. Interestingly, similar to stem cells in normal tissues, Lgr5 + cells were often restricted to the base of the tumor glands, and such Lgr5 + restriction was associated with high levels of intestinal stem cell markers such as EPHB2, OLFM4, and ASCL2. Thus, our findings show that Lgr5 + cells are present at the base of the antral glands in the human stomach and that this cell population significantly expands in intestinal metaplasias. Furthermore, Lgr5 + cells are seen in a large number of gastric tumors ; their frequent basal arrangements and coexpression of ISC markers support the idea that Lgr5 + cells act as stem cells during the early stage of intestinal-type gastric tumorigenesis.

Prognostic significance of leucine-rich-repeat-containing G-protein-coupled receptor 5, an intestinal stem cell marker, in gastric carcinomas

“…In addition, we previously demonstrated overexpression of LGR5 in gastric adenomas compared with normal gastric mucosa [25]. Unexpectedly, however, we found that the mean level of LGR5 in GCs was significantly lower than that in matched noncancerous gastric tissues.…”

“…Using monoclonal antibodies against human LGR5 developed in the laboratory, Kemper et al [13] provided evidence that LGR5 is also a marker for human colorectal cancers. However, the possibility of its use as a stem cell marker in GCs has not been investigated yet even though LGR5 expression has been demonstrated through GC progression; normal gastric epithelium, precancerous lesion, adenoma, and carcinoma [17,25]. Because of the lack of commercially available antibodies that can recognize the extracellular domain and isolate Kaplan-Meier analysis demonstrated that LGR5 positivity has no prognostic influence in gastric cancer patients (n = 603, P = 0.560).…”

“…ISH for LGR5 was performed with an RNAscope FFPE assay kit (Advanced Cell Diagnostics, Hayward, CA, USA) as described previously [25]. In brief, 4-lm FFPE tissue sections were pretreated with heat and protease digestion followed by hybridization with LGR5 probe.…”

“…However, for GCs, only a limited number of studies have investigated LGR5 expression and its relevance in predicting clinical outcomes [17,23,24]. Previously, we specifically identified LGR5-expressing cells in normal gastric mucosa and intestinal metaplastic lesions as well as gastric adenomas by RNA in situ hybridization (ISH) [25]. In this study, we investigated the expression of LGR5 messenger RNA (mRNA) in a large number of GC patients and analyzed its significance in the prognosis of GC patients.…”

TMBIM6 (transmembrane BAX inhibitor motif containing 6) enhances autophagy and reduces renal dysfunction in a cyclosporine A-induced nephrotoxicity model

“…72 Briefly, 4-mm-thick paraffin-embedded tissue sections were deparaffinized and pretreated with heat and proteases, then hybridized with a target probe for the Tmbim6 gene. Next, an HRP-based signal amplification system was hybridized to the target probe before color development with 3, 3 0 -diaminobenzidine tetrahydrochloride (Advanced Cell Diagnostics, 310033).…”