Nonreceptor tyrosine phosphatase 14 promotes proliferation and migration through regulating phosphorylation of YAP of Hippo signaling pathway in gastric cancer cells.

BACKGROUND: The Hippo signaling pathway is associated with cell proliferation and organ size, and its transcriptional coactivator Yes-associated protein (YAP), emerges as a crucial oncoprotein in multiple cancers. It was increasingly recognized that nonreceptor tyrosine phosphatase 14 (PTPN14) was relevant to the cell membrane and cytoskeleton, and had a critical effect on cell adhesion, growth, and actin cytoskeleton organization. Furthermore, PTPN14 was also certified to operate the translocation and phosphorylation of YAP. The present experiment was aimed to explore the impact of PTPN14 on gastric cancer (GC) cell proliferation and migration through regulating the phosphorylation of YAP. METHODS: The pEGFP-N1-PTPN14 recombinant plasmid was stably transfected into three differentiation degrees GC cell lines, including MKN-28, SGC-7901, and BGC-823. Quantitative reverse transcription-polymerase chain reaction and Western blot assay were performed to analyze the messenger RNA (mRNA) and protein levels. The proliferative and migratory capacity of cells was appraised by Cell Counting Kit-8 assay and transwell chamber. RESULTS: Compared with the normal control and vector transfection group, the capacity of these three cell lines, which transfected with the pEGFP-N1-PTPN14 to proliferate and migrate in vitro was increased obviously (P < .05). There was no YAP mRNA detected in MKN-28 cell line. Meanwhile, after transfecting the pEGFP-N1-PTPN14 plasmid, the mRNA level of YAP in SGC-7901 was reduced (P < .05), and it was increased in BGC-823 (P < .05). The YAP protein level in SGC-7901 and BGC-823 has no apparent transformation by transfecting, but the protein level of phospho-Ser127 YAP and phospho-Ser397 YAP is upregulated (P < .05). CONCLUSION: PTPN14 could enhance the proliferative and migratory ability of GC cells by promoting the YAP phosphorylation in the Hippo signaling pathway. Taken together, PTPN14 might be involved in the occurrence and development of GC and become a molecular regulator to treat GC.

Serum Helicobacter pylori FliD antibody and the risk of gastric cancer.

FliD and CagA are important virulence factors of H. pylori. We aimed to evaluate the screening values of FliD and CagA for gastric cancer (GC). Serum samples were obtained from 232 cases and 266 controls in a case-control study. Unconditional multivariate logistic regression with odds ratios (ORs) and 95% confidence intervals (CIs) was used to analyze the relationships between FliD, CagA and GC. The sensitivities, specificities and receiver operating characteristic (ROC) curves were calculated. Finally, the combined screening values of FliD, FlaA, NapA and CagA were assessed based on discriminant analysis. In all subjects, the associations of FliD and CagA with GC were evident with ORs (95% CIs) of 7.6 (4.7-12.3) and 2.5 (1.6-3.8), respectively (*p<0.001). The areas under ROC curves (AUCs) for FliD and CagA were 0.800 and 0.653, respectively. The AUC for the combination of FliD, FlaA and NapA was 0.915, which represented an increase of 0.115 over that of FliD alone (*p<0.001). These findings indicate that the FliD antibody is associated with GC and could exhibit high validity as a biomarker in screening for GC patients. The combination of FliD, FlaA and NapA improved the screening validity.

Constitutive expression of PPARγ inhibits proliferation and migration of gastric cancer cells and down-regulates Wnt/ß-Catenin signaling pathway downstream target genes TERT and ENAH.

BACKGROUND: Peroxisome proliferator-activated receptor γ (PPARγ) is a member of the PPAR nuclear hormone receptor superfamily, which plays a crucial role in carcinogenesis. Wnt/ß-Catenin signaling pathway has been well certified to contribute to the progression of gastric malignancies. ß-Catenin mediates transcriptional regulation by forming a complex with LEF/TCF transcription factors, resulting in activation of downstream target genes such as TERT, ENAH. In this study, we aimed at detecting the effect of PPARγ on TERT, ENAH and explaining the further mechanisms of PPARγ on tumor suppression. METHODS: The pEGFP-N1-PPARγ recombinant plasmid has already been constructed by researchers in our laboratory. We stably transfected it into three gastric cancer (GC) cell lines (MKN-28, SGC-7901 and BGC-823). CCK-8 and transwell assay were employed to analyze the capability of cell proliferation and metastasis. The mRNA and protein levels were evaluated by real-time PCR and western blot analysis. RESULTS: After transfected with PPARγ overexpression plasmid, the ability of cell proliferation and migration declined significantly (p<0.05). The expression of PPARγ increased (p<0.05) and ß-Catenin was inhibited obviously (p<0.05) in the group of pEGFP-N1-PPARγ plasmid transfection. Meanwhile, the mRNA or protein levels of TERT and ENAH were suppressed (p<0.05) in pEGFP-N1-PPARγ plasmid transfection group compared with control groups. CONCLUSION: PPARγ might inhibit the proliferation and migration of GC cell lines through suppressing the expression of TERT and ENAH. PPARγ played an important role as a physiological regulator and might be a target for the treatment of GC.