Gastrokine 1 mRNA in human sera is not informative biomarker for gastric cancer

Gastric Signet Ring Cell Carcinoma: A Comparative Analysis of Clinicopathologic Features

Signet ring cell carcinoma (SRC) is a distinct histological subtype of gastric carcinoma. Our aim is to investigate differential characteristics between gastric SRC and other non SRC carcinomas (nSRC). It was a retrospective study including 183 patients diagnosed with gastric carcinoma over a period of 5 years at our pathology department. We performed statistical comparison of clinicopathological features between patients with SRC and those with nSRC. 127 patients (69.4%) had nSRC, 56 had SRC (30.6%), the mean age was 56.67 ± 14.03 years. Patients with SRC were younger than those with nSRC (mean age of 49.66 versus 59.76, P = 0.030). Patients with SRC tend to have more diffuse tumors in the stomach (P = 0.005), with flat macroscopic appearance (P = 0.001). Patients with SRC present more often with pT3 tumors (P < 0.001), lymph node metastasis (P = 0.024) and perineural invasion (P = 0.003). There were no significant differences between SRC and nSRC in gender, vascular invasion or distant metastasis (P > 0.05). The median survival time was 42.82 ± 1.70 months. Patients with nSRC live longer than those with SRC, but the difference was not significant (P = 0.28). SRC is a histological subtype of gastric carcinoma with distinctive clinicopathologic features. The clinical management of patients should take into account these particular features.

Gastrokine-1, an anti-amyloidogenic protein secreted by the stomach, regulates diet-induced obesity

Obesity and its sequelae have a major impact on human health. The stomach contributes to obesity in ways that extend beyond its role in digestion, including through effects on the microbiome. Gastrokine-1 (GKN1) is an anti-amyloidogenic protein abundantly and specifically secreted into the stomach lumen. We examined whether GKN1 plays a role in the development of obesity and regulation of the gut microbiome. Gkn1-/- mice were resistant to diet-induced obesity and hepatic steatosis (high fat diet (HFD) fat mass (g) = 10.4 ± 3.0 (WT) versus 2.9 ± 2.3 (Gkn1-/-) p < 0.005; HFD liver mass (g) = 1.3 ± 0.11 (WT) versus 1.1 ± 0.07 (Gkn1-/-) p < 0.05). Gkn1-/- mice also exhibited increased expression of the lipid-regulating hormone ANGPTL4 in the small bowel. The microbiome of Gkn1-/- mice exhibited reduced populations of microbes implicated in obesity, namely Firmicutes of the class Erysipelotrichia. Altered metabolism consistent with use of fat as an energy source was evident in Gkn1-/- mice during the sleep period. GKN1 may contribute to the effects of the stomach on the microbiome and obesity. Inhibition of GKN1 may be a means to prevent obesity.

Regulation of GKN1 expression in gastric carcinogenesis: A problem to resolve (Review)

Gastrokine 1 (GKN1) is a protein expressed on the surface mucosa cells of the gastric antrum and fundus, which contributes to maintaining gastric homeostasis, inhibits inflammation and is a tumor suppressor. The expression of GKN1 decreases in mucosa that are either inflamed or infected by Helicobacter pylori, and is absent in gastric cancer. The measurement of circulating GKN1 concentration, the protein itself, or the mRNA in gastric tissue may be of use for the early diagnosis of cancer. The mechanisms that modulate the deregulation or silencing of GKN1 expression have not been completely described. The modification of histones, methylation of the GKN1 promoter, or proteasomal degradation of the protein have been detected in some patients; however, these mechanisms do not completely explain the absence of GKN1 or the reduction in GKN1 levels. Only NKX6.3 transcription factor has been shown to be a positive modulator of GKN1 transcription, although others also have an affinity with sequences in the promoter of this gene. While microRNAs (miRNAs) are able to directly or indirectly regulate the expression of genes at the post‑transcriptional level, the involvement of miRNAs in the regulation of GKN1 has not been reported. The present review analyzes the information reported on the determination of GKN1 expression and the regulation of its expression at the transcriptional, post‑transcriptional and post‑translational levels; it proposes an integrated model that incorporates the regulation of GKN1 expression via transcription factors and miRNAs in H. pylori infection.

The role and diagnostic potential of gastrokine 1 in gastric cancer

Introduction

Gene for gastrokine 1 (GKN1) was identified as one of the most significant in gastric cancer and indicated as a potential therapeutic target.

Aim

The aim was a review of literature reports concerning the role and diagnostic potential of GKN1 in gastric cancer.

Materials and methods

PubMED database was searched for sources using the following keywords: gastrokine 1/GKN1/AMP-18 and gastric cancer, Helicobacter pylori, aspirin, nonsteroidal anti-inflammatory drugs. Preference was given to the sources which were published within the past 10 years.

Conclusion

GKN1 is a stomach-specific protein, and its role consists of maintaining mucosal integrity as well as the replenishment of the surface lumen epithelial cells layer. The evaluation of GKN1 expression seems to be a useful indicator of the presence of neoplastic or inflammatory lesions in the gastric mucosa. GKN1 expression is decreased in gastric tumor tissues and derived cell lines and its upregulation in cell lines of gastric cancer induces cells apoptosis. The mechanism by which GKN1 is inactivated in gastric cancer cells is still not fully understood. The future diagnostic capabilities of gastric cancer concern the assessment of serum GKN1 concentration by means of ELISA method. Serum GKN1 concentration is not related to patients’ sex. Moreover, the measurement of GKN1 concentration is possible only after the incubation of samples at 70°C for 10 minutes. Nevertheless, the aspect of quantitative serum GKN1 evaluation is new in the context of available literature and requires further studies.

Gastrokine 1 protein is a potential theragnostic target for gastric cancer

BACKGROUND

Gastrokine 1 (GKN1) plays important roles in maintaining mucosal homeostasis, and in regulating cell proliferation and differentiation. Here, we determined whether GKN1 is a potential theragnostic marker for gastric cancer.

METHODS

We identified GKN1 binding proteins using the protein microarray assay and investigated whether GKN1 is one of the exosomal cargo proteins by western blot, immunoprecipitation, and immunofluorescent assays. Cell proliferation and apoptosis were analyzed by MTT, BrdU incorporation, flow cytometry, and western blot assays. We further validated the functional relevance of exosomal GKN1 in MKN1-injected xenograft mice. The possibility of serum GKN1 as a diagnostic marker for gastric cancer was determined by ELISA assay.

RESULTS

In protein microarray assay, GKN1 binding to 27 exosomal proteins was clearly observed. GKN1 was expressed in exosomes derived from HFE-145 gastric epithelial cells by western blot and immunofluorescent assays, but not in exosomes from AGS and MKN1 gastric cancer cells. Exosomes carrying GKN1 inhibited cell proliferation and induced apoptosis in both AGS and MKN1 cells, and exosomes carrying GKN1-treated nude mice-bearing MKN1 xenograft tumors exhibited significantly reduced tumor volume and tumor weight. Silencing of clathrin markedly down-regulated the internalization of exosomal GKN1. Interestingly, serum GKN1 concentrations in patients with gastric cancer were significantly lower than those in healthy individuals and patients with colorectal and hepatocellular carcinomas.

CONCLUSIONS

The GKN1 is secreted and internalized in the gastric epithelium by exosome-driven transfer, which inhibits gastric tumorigenesis and supports the clinical application of GKN1 protein in gastric cancer diagnosis and treatment.

Diagnostic and prognostic value of serum interleukin‑16 in patients with gastric cancer

Gastric cancer (GC) is one of the major leading causes of cancer‑associated mortality worldwide. Serum biomarkers have a vital role in diagnosis and prognosis of GC, and interleukin (IL)‑16 may serve as a useful biomarker with prognostic value for human cancers. The current study aimed to evaluate the expression level of serum IL‑16 in patients with GC, and evaluate the diagnostic and prognostic value of IL‑16. ELISA was performed determine the serum IL‑16 levels in patients with GC and healthy controls. Receiver operator curve analysis was performed to evaluate the diagnostic and prognostic potential value of serum IL‑16 in GC diagnosis. Migration and invasion assays were performed using cells with IL‑16 small interfering RNA (siRNA) knockdown. The results demonstrated that serum IL‑16 levels were significantly higher in GC samples than in healthy controls, and increased serum IL‑16 levels were significantly associated with tumor recurrence and poor prognosis. Knockdown of IL‑16 significantly suppressed the migration and invasion of GC cells. In conclusion, the current results indicate that serum IL‑16 levels may have diagnostic and prognostic value for patient with GC.