Immunoexpression of LGR4 and Β-Catenin in Gastric Cancer and Normal Gastric Mucosa

Rspo2-LGR4 exacerbates hepatocellular carcinoma progression via activation of Wnt/β-catenin signaling pathway

BACKGROUND

The leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4) plays an important role in stem cell differentiation, organ development and cancer. Whether LGR4 affects the progression of hepatocellular carcinoma (HCC) remains unknown. This study aimed to reveal the role of LGR4 in HCC.

METHODS

Clinical samples of HCC were collected to assess the expression of LGR4 and its correlation with patients' clinical characteristics. The expression level of LGR4 in HCC cells was altered by pharmacological and genetic methods, and the role of LGR4 in HCC progression was analyzed by in vivo and in vitro assays. HCC was induced by diethylnitrosamine (DEN) and carbon tetrachloride (CCl4) in wild-type and LGR4 deficient mice, the effect of LGR4 on HCC was examined by histopathological evaluation and biochemical assays.

RESULTS

LGR4 expression was up-regulated in HCC samples, and its expression level was positively correlated with tumor size, microvascular invasion (MVI), TNM stage and pathological differentiation grade of HCC patients. In the mouse HCC model induced by DEN+CCl4, knockdown of LGR4 effectively inhibited the progression of HCC. Silencing of LGR4 inhibited the proliferation, migration, invasion, stem cell-like properties and Warburg effect of HCC cells. These phenotypes were promoted by R-spondin2 (Rspo2), an endogenous ligand for LGR4. Rspo2 markedly increased the nuclear translocation of β-catenin, whereas IWR-1, an inhibitor of Wnt/β-catenin signaling, reversed its effect. Deficiency of LGR4 significantly reduced the nuclear translocation of β-catenin and the expression of its downstream target genes cyclinD1 and c-Myc.

CONCLUSIONS

LGR4 promotes HCC progression via Wnt/β-catenin signaling pathway.

Histopathological features of glandular atrophy of the lamina propria of the gastric mucosa during its occurrence and development

OBJECTIVE

To explore the histopathological features of glandular atrophy of the lamina propria of gastric mucosa during its occurrence and development.

METHOD

We performed detailed histological observation and immunohistochemical examination on the endoscopic biopsy and ESD endoscopic resection specimens of 896 patients with glandular atrophy of the lamina propria of gastric mucosa. The EnVision two-step method was used for immunohistochemical staining, and the slices were incubated with primary antibody CK7, CK20, villin, CDX2, MUC5AC, MUC6, p53 and ki-67. Hematoxylin staining was performed and observed under the microscope and statistically analyzed.

RESULTS

In the initial stage of glandular atrophy of the lamina propria, the proliferation area of the deep gastric pits, and the isthmus and neck of the gastric glands are characterized by roughly normal structure of the glandular structure, increased mesenchyme, and widened space between glands. Subsequently, the gland becomes smaller in volume and less in number, especially at the base, in the gastric glandular part of the gastric unit. The disease at this stage has higher incidence, and occurs more often in the elderly who account for 64.0% (573/896) of our study group. The disease in this stage may exhibit some lesions that are physiologic (age-related degeneration) while others are pathological. Therefore, this condition is called simple glandular atrophy of the lamina propria of the gastric mucosa. When the gastric mucosal epithelium is subjected to infection or repeated infections, chemical stimuli, immune factors, and genetic factors, it can lead to the proliferation and transformation of stem cells in the proliferation area of the deep gastric pits, and the isthmus and neck of the gastric glands, forming single ducts, multiple ducts, or a proliferation of patchy cells. Then, atypical hyperplasia (intraepithelial neoplasia) presents, finally leading to gastric adenocarcinoma.

CONCLUSION

Understanding the histopathological characteristics of glandular atrophy of the lamina propria of gastric mucosa is of great significance in controlling the occurrence and development of gastric cancer.

LGR4 promotes tumorigenesis by activating TGF-β1/Smad signaling pathway in multiple myeloma

Multiple myeloma (MM) is a common hematologic malignancy that remains incurable. Although accumulating evidence suggests that the leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4) plays a biological function in a variety of cancers, its biological function and molecular mechanisms in MM are unclear. In the present study, we found that LGR4 was significantly upregulated in MM tissues and cells. In vitro and in vivo experiments showed that knockdown of LGR4 significantly inhibited proliferation of MM cells, promoted apoptosis and arrested cell cycle in G1. Overexpression showed the opposite effect. Mechanistic studies revealed that LGR4 could interact with TGF-β1 and regulate TGF-β1 expression, thereby activating the TGF-β1/Smad signaling pathway and promoting MM progression. LGR4 may be a potential new target for MM diagnosis and treatment.

The occurrence, progression and development of four types of gastric mucosal atrophic lesions and their histopathological characteristics

OBJECTIVE

To investigate the occurrence and development of gastric mucosal atrophic lesions and their histopathological characteristics.

METHODS

Histopathological diagnosis and immunohistochemical staining using the EnVision two-step method were conducted on 1969 gastric mucosal atrophic lesions obtained from gastroscopic biopsy specimens. A total of 48-month three-stage endoscopic biopsy follow-ups were performed.

RESULTS

When the gastric mucosal epithelium was affected by infection, chemical irritation, or immune or genetic factors, the gastric mucosal epithelium glands atrophied, the mucosa became thinner, the number of glands decreased, the intestinal epithelium progressed to metaplasia and smooth muscle fibre became hyperplasia. Such changes may lead to the proliferation and dysplasia of epithelial cells of the gastric mucosa and neoplastic hyperplasia in nature; this is referred to as gastric mucosal atrophic lesions in this study. According to this definition, the present study divided gastric mucosal atrophy into four types: (1) glandular atrophy of the lamina propria; (2) compensatory proliferative atrophy; (3) intestinal metaplasia atrophy; and (4) smooth muscle proliferative atrophy. The incidence rates of the above were 40.1% (789/1969), 14.3% (281/1969), 27.8% (547/1969) and 17.9% (352/1969), respectively. One- to 4-year follow-ups found that the changes were not significant and that the percentages of patients with disease exacerbation were 85.7% (1688/1969) and 9.8% (192/1969). The percentages of patients who developed low-grade intraepithelial neoplasia and high-grade intraepithelial neoplasia were 2.8% (55/1969) and 1.1% (21/1969), respectively; 0.7% (13/1969) of patients developed intramucosal cancer.

CONCLUSION

Gastric mucosal atrophic lesions and histopathological staging are based on the morphological characteristics of gastric mucosal atrophy and the hypothesis of malignant transformation of cells during the occurrence and development of mucosal atrophy. Mastering pathological staging is beneficial to clinicians for enacting precise treatment and is important for reducing the incidence of gastric cancer.

Landscape of Druggable Molecular Pathways Downstream of Genomic CDH1/Cadherin-1 Alterations in Gastric Cancer

Loss of CDH1/Cadherin-1 is a common step towards the acquisition of an abnormal epithelial phenotype. In gastric cancer (GC), mutation and/or downregulation of CDH1/Cadherin-1 is recurrent in sporadic and hereditary diffuse GC type. To approach the molecular events downstream of CDH1/Cadherin-1 alterations and their relevance in gastric carcinogenesis, we queried public databases for genetic and DNA methylation data in search of molecular signatures with a still-uncertain role in the pathological mechanism of GC. In all GC subtypes, modulated genes correlating with CDH1/Cadherin-1 aberrations are associated with stem cell and epithelial-to-mesenchymal transition pathways. A higher level of genes upregulated in CDH1-mutated GC cases is associated with reduced overall survival. In the diffuse GC (DGC) subtype, genes downregulated in CDH1-mutated compared to cases with wild type CDH1/Cadherin-1 resulted in being strongly intertwined with the DREAM complex. The inverse correlation between hypermethylated CpGs and CDH1/Cadherin-1 transcription in diverse subtypes implies a common epigenetic program. We identified nonredundant protein-encoding isoforms of 22 genes among those differentially expressed in GC compared to normal stomach. These unique proteins represent potential agents involved in cell transformation and candidate therapeutic targets. Meanwhile, drug-induced and CDH1/Cadherin-1 mutation-related gene expression comparison predicts FIT, GR-127935 hydrochloride, amiodarone hydrochloride in GC and BRD-K55722623, BRD-K13169950, and AY 9944 in DGC as the most effective treatments, providing cues for the design of combined pharmacological treatments. By integrating genetic and epigenetic aspects with their expected functional outcome, we unveiled promising targets for combinatorial pharmacological treatments of GC.

How Does Helicobacter pylori Infection Cause Gastric Mucosal Atrophy

Objective

To investigate the occurrence and development of gastric mucosal atrophy due to Helicobacter pylori (Hp) infection and the accompanying histomorphological features.

Methods

Detailed histological observations and immunohistochemical examinations were conducted via 197 endoscopic biopsies and endoscopic submucosal dissection specimens of gastric mucosal atrophic lesions with gastric Hp infection. Detailed observation was made of columnar cells in the proliferative region of the deep gastric pit and the isthmus of the gastric gland, as well as the upper part of the glandular cervix.

Results

The infection of the gastric mucosa by Hp firstly led to the proliferative disorder of stem cells in the normal proliferative region of the gastric mucosa. This caused substantial propagation of cells in the proliferative region of the deep gastric pit and the isthmus of the gastric gland, as well as the upper part of the glandular cervix, as a means to replenish the damaged surface mucus cells. However, the propagation of stem cells in the proliferative region was insufficient for downward migration, and the normal physiological process of differentiation into fundic/pyloric gland cells was disrupted, resulting in glandular atrophy of the intrinsic layer of the gastric mucosa. Persistent Hp infection and disruption of stem cell proliferation in the proliferative region subsequently resulted in extensive segmental hyperplasia of the gastric mucosa and glandular atrophy of the lamina propria.

Conclusion

The occurrence, development, and histomorphological features of gastric mucosal atrophy due to gastric Hp infection provide a reliable pathological basis for precise treatment by clinicians and are of great significance for controlling the development of gastric cancer.

Emerging Roles for LGR4 in Organ Development, Energy Metabolism and Carcinogenesis

The leucine-rich repeats containing G protein-coupled receptor 4 (LGR4) belonging to G protein-coupled receptors (GPCRs) family, had various regulatory roles at multiple cellular types and numerous targeting sites, and aberrant LGR4 signaling played crucial roles in diseases and carcinogenesis. On the basis of these facts, LGR4 may become an appealing therapeutic target for the treatment of diseases and tumors. However, a comprehensive investigation of its functions and applications was still lacking. Hence, this paper provided an overview of the molecular characteristics and signaling mechanisms of LGR4, its involvement in multiple organ development and participation in the modulation of immunology related diseases, metabolic diseases, and oxidative stress damage along with cancer progression. Given that GPCRs accounted for almost a third of current clinical drug targets, the in-depth understanding of the sophisticated connections of LGR4 and its ligands would not only enrich their regulatory networks, but also shed new light on designing novel molecular targeted drugs and small molecule blockers for revolutionizing the treatment of various diseases and tumors.

Cancerous and non-neoplastic stem cells in the stomach similarly express CD44 and CD133

CD44 and CD133 have been considered as cancer stem cell (CSC) markers. Stem cell markers are rarely described in healthy stomach tissues. However, the clinicopathological and prognostic value of CD44 and CD133 in gastric cancer remains controversial. This study investigated the expression of CD44 and CD133 in gastric cancer and non-neoplastic gastric mucosa. We used samples of primary gastric adenocarcinomas (n = 69), metastatic lymph nodes (n = 30), intestinal metaplasia (n = 17), and histologically normal gastric tissues of surgical margins (n = 54). The expression of CD44 and CD133 were studied in samples by immunohistochemistry. Fisher's exact test and a logistic regression model were used in this study. CD44 expression was observed in 12% of samples with intestinal metaplasia, 20% with lymph node metastases, 22% with normal mucosa, to 30% of samples with primary tumors. Most of these positive tumors showed immunostaining in less than 4% of cancerous cells, mainly in the diffuse type. CD133 expression was observed in 7% (intestinal metaplasia) to 46% (normal mucosa). In the positive cases of cancer (24%), in most of them, less than 3% of cells were marked. CD44 and CD133 expression in the histologically normal gastric mucosa was restricted to the deeper regions of the gastric crypts at the level where stem cells and progenitor cells are usually found. CD44 and CD133 expression occurs in few gastric cancer cells, mainly in diffuse carcinomas, and are expressed in histologically normal gastric mucosae. None of the markers are specific for cancer and are also present in intestinal metaplasia and the normal mucosa.

Comprehensive analysis of ceRNA networks in HPV16- and HPV18-mediated cervical cancers reveals XIST as a pivotal competing endogenous RNA

Cervical cancer (CC) is one of the most common cancers in women worldwide, being closely related to high-risk human papillomavirus (HR-HPVs). After a particular HR-HPV infects a cervical cell, transcriptional changes in the host cell are expected, including the regulation of lncRNAs, miRNAs, and mRNAs. Such transcripts may work independently or integrated in complex molecular networks - as in competing endogenous RNA (ceRNA) networks. In our research, we gathered transcriptome data from samples of HPV16/HPV18 cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC), from The Cancer Genome Atlas (TCGA) project. Using GDCRNATools, we identified ceRNA networks that differentiate HPV16- from HPV18-mediated CESC. For HPV16-CESC, three lncRNA-mRNA co-expressed pairs were reported, all led by the X-inactive specific transcript (XIST): XIST | DLG5, XIST | LGR4, and XIST | ZNF81. The XIST | LGR4 and XIST | ZNF81 pairs shared 11 miRNAs, suggesting an increased impact on their final biological effect. XIST also stood out as an important lncRNA in HPV18-CESC, leading 35 of the 42 co-expressed pairs. Some mRNAs, such as ADAM9 and SLC38A2, emerged as important players in the ceRNA regulatory networks due to sharing a considerable amount of miRNAs with XIST. Furthermore, some XIST-associated axes, namely XIST | miR-23a-3p | LGR4 and XIST | miR-30b-5p or miR-30c-5p or miR-30e-5p I ADAM9, had a significant impact on the overall survival of HPV16- and HPV18-CESC patients, respectively. Together, these data suggest that XIST has an important role in HPV-mediated tumorigenesis, which may implicate different molecular signatures between HPV16 and HPV18-associated tumors.

LGR4 overexpression is associated with clinical parameters and poor prognosis of serous ovarian cancer

OBJECTIVE

LGR4 expression in serous ovarian cancer paraffin-embedded tissues and fresh tissues were investigated, and its expression associated with clinicopathological parameters and prognosis in serous ovarian cancer was explored.

METHODS

From Dec, 2009 to Jan, 2020, 122 paraffin-embedded serous ovarian cancer patients and 41 paired paratumor tissues who were both diagnosed and operated at the memorial hospital of Sun Yat-sen University and Integrated Hospital of Traditional Chinese Medicine, Southern Medical University were selected in this research, respectively, and all of these tissues were performed by immunohistochemistry (IHC) with a polyclonal antibody for LGR4. Meanwhile, from Aug, 2013 to Mar, 2019, 15 cases of serous ovarian cancer fresh tissues and 15 cases of paratumor fresh tissues who were operated at Integrated Hospital of Traditional Chinese Medicine, Southern Medical University were performed with Quantitative Real-time PCR to detect the mRNA expression of LGR4, respectively.

RESULTS

LGR4 expression was much higher both in paraffin-embedded and fresh cancer tissues than that in paratumor tissues, respectively, and its expression was associated with recurrence free survival and overall survival in serous ovarian cancer patients. Moreover, in a multivariate model LGR4 was an indeed independent predictor of poor survival in serous ovarian cancer patients.

CONCLUSION

LGR4 is upregulated in serous ovarian cancer, and LGR4 is an indeed useful independent prognostic predictor in serous ovarian cancer, and it may provide important clinical value of serous ovarian cancer.