Epigenetic downregulation of MUC17 by H. pylori infection facilitates NF-κB-mediated expression of CEACAM1-3S in human gastric cancer

Abstract

Background and aims Helicobacter pylori invades the mucosal barrier and infects the mucins of gastric epithelial cells. However, whether gastric carcinogenesis caused by H. pylori infection involves the membrane-bound mucins is unclear. This study explored the role of mucin 17 (MUC17) in gastric cancer (GC) associated with H. pylori infection. Methods The expression of MUC17 and carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) was examined in human GC cells and tissues with H. pylori infection. Gain-and loss-of-function assays were performed to assess the role of MUC17 in regulating CEACAM1 in H. pylori-infected GC cells. Results MUC17 was downregulated in H. pylori-infected GC cells and tissues in association with poor survival of GC patients. Downregulation of MUC17 was attributable to MUC17 promoter methylation mediated by DNA methyltransferase 1 (DNMT1) H. pylori-enhanced GC cell proliferation and colony formation associated with MUC17 downregulation. Gain-and loss-of-function assays showed that MUC17 inhibited the H. pylori-enhanced GC cell growth by preventing the translocation of H. pylori CagA into GC cells. Moreover, MUC17 downregulated the expression of CEACAM1 variant 3S (CEACAM1-3S) in GC cells and tissues with H. pylori infection. Additionally, MUC17 downregulated CEACAM1 promoter activity via attenuation of NF-κB activation in GC cells. Conclusions MUC17 was epigenetically downregulated in GC with H. pylori infection. MUC17 inhibited H. pylori CagA translocation via attenuation of NF-κB-mediated expression of CEACAM1-3S in GC cells. Thus, MUC17 may serve as a valuable prognostic biomarker for H. pylori-associated GC.

Systematic profiling of alternative splicing in Helicobacter pylori-negative gastric cancer and their clinical significance

“…And this result was consistent with the conclusion of another study, which illustrated that HP − GC patients are in stage IV more and have worse overall survival (OS) compared to HP+ GC patients [6]. Although the prognostic biomarkers of HP+ GC have been widely studied previously [7][8][9], the related research is few in HP − GC. Therefore, it is necessary for us to explore the prognostic factors of HP − GC patients.…”

Differential MUC22 expression by epigenetic alterations in human lung squamous cell carcinoma and adenocarcinoma

“…. DNA extraction, bisulfite modification and MSP-PCR were performed as previously described (19,21). Genomic DNA was extracted from tissues using the QIAamp DNA mini Kit (Qiagen) followed by quantitative analysis using NanoDrop 1000 spectrophotometer (Thermo Fisher Scientific, Inc.).…”

“…MSP-qPCR was performed by using primer pairs specifically for either methylated or unmethylated sequences of the MUC22 (Table SII). The relative level of methylation and unmethylation of MUC22 promoter region was normalized to β-actin using the 2 -ΔΔCq method (19,22). MSP products were analyzed using a 2% agarose gel electrophoresis.…”

“…Horseradish peroxidase-conjugated anti-mouse (1:2,500 dilution) or anti-rabbit (1:2,500 dilution) secondary antibodies were purchased from Bioworld Technology, Inc. Immunoreactive bands were visualized by using the Amersham ECL Western Blotting Detection Kit (Cytiva) according to the manufacturer's instructions. β-actin served as a loading control (19,23).…”

“…Cell lines were split to low density (30% confluence) and grown in 90% RPMI-1640 medium (Gibco; Thermo Fisher Scientific, Inc.) with 10% fetal bovine serum (FBS; Gibco; Thermo Fisher Scientific, Inc.). Before collection, cells were also treated with 5-aza-2'-deoxycytidine (5-Aza) (5 µM; Sigma-Aldrich; Merck KGaA) for 96 h with the growth medium being changed every 24 h, or TSA (5 µM, Sigma-Aldrich; Merck KGaA) for 24 h as previously described (19).…”