Circ_0000190 suppresses gastric cancer progression potentially via inhibiting miR-1252/PAK3 pathway.

BACKGROUND: Gastric cancer is a serious malignant tumor associated with aberrant circular RNAs (circRNAs) expression. In this study, we aim to investigate the role and the underlying mechanism of circ_0000190, a circRNA in gastric cancer. METHODS: Circ_0000190 expression in vivo was examined in gastric cancer and adjacent normal tissues by RT-PCR. Circ_0000190 expression in gastric cancer cell lines was detected by FISH and RT-PCR. The role of the circRNA in gastric cancer cells was assessed by the analysis of cell viability, apoptosis, proliferation, cell cycle and migration. The potential effector of circ_0000190 was predicted by computational screen and validated by luciferase reporter assay. Furthermore, Mice model of human gastric cancer was established to observe the underlying mechanisms of circ_0000190. RESULTS: Circ_0000190 was down-regulated in gastric cancer tissues and cells, with a major location in cytoplasm. Circ_0000190 inhibited gastric cancer cell viability, proliferation and migration, and induced apoptosis and cell cycle arrest by regulating the expression of capase-3, p27 and cyclin D. In addition, the circRNA was validated as a sponge of miR-1252, which directly targeted PAK3. The effects of circ_0000190 on the cellular processes were blocked by miR-1252 mimics, which could be rescued after further overexpression of PAK3. CONCLUSIONS: Circ_0000190 suppresses gastric cancer progression potentially via inhibiting miR-1252/PAK3 pathway, employing circ_0000190 might be a promising therapeutic strategy for the treatment of gastric cancer.

BIX-01294 enhanced chemotherapy effect in gastric cancer by inducing GSDME-mediated pyroptosis.

Adjuvant chemotherapy in combination with surgery is expected to be a curative strategy for gastric cancer. However, drug resistance remains an obstacle in effective chemotherapy. Therefore, understanding the potential mechanisms of chemotherapy induced gastric cancer cell death is of great importance. We demonstrated that BIX-01294 (BIX) at low concentration could induce autophagic flux by converting LC3B-I to LC3B-II and directly activate autophagy associated cell death in gastric cancer cell lines at high concentration. BIX at low concentration could help obtain sensitivity of gastric cancer cells to chemotherapy with significantly reduced cell viability. Interestingly, BIX combined Cis (BIX + Cis) treated SGC-7901 cells display pyroptosis related cell death with large bubbles blown around the membrane, significantly decreased cell viability, elevated lactate dehydrogenase release and increased percentage of propidium iodide and Annexin-V double positive cells. Furthermore, the cleavage of gasdermin E (GSDME) and caspase-3 but not GSDMD was detected by immunoblotting and the knockout of GSDME switched pyroptosis into apoptosis in the BIX + Cis combined treated group. Furthermore, the deficiency of Beclin-1 to inhibit BIX induced autophagic flux completely blocked BIX + Cis combined treated induced cell pyroptosis related cell death. Additionally, BIX + Cis in vivo treatment could inhibit tumor growth, which could be reversed by the deficiency of Beclin-1 and be delayed by the deficiency of GSDME. In conclusion, our data was the first to reveal that BIX enhanced the anticancer chemotherapy effect by induced GSDME-mediated pyroptosis through the activation of autophagic flux in gastric cancer cells.

Expression of protease-activated receptor-2 in human gastric stromal tumor and its clinicopathological significance.

BACKGROUND/AIMS: To explore the expression of protein-activated receptor-2 (PAR-2) in human gastric stromal tumor and its clinicopathological significance. METHODOLOGY: The expression of PAR-2 was detected with immunohistochemisty, RT-PCR and Western blot in tumor tissue, peritumoral tissue and gastric normal tissue from 72 patients with gastric stromal tumor. RESULTS: PAR-2 expression was significantly higher in peritumoral tissue (p < 0.05) and tumor tissue (p < 0.01) than in gastric normal tissue, and significantly higher in tumor tissue than in peritumoral tissue (p < 0.01). With the increase in NIH grade, PAR-2 expression was elevated in tumor tissues. PAR-2 expression was strongly associated with mucosal invasion. CONCLUSIONS: PAR-2 expression is significantly higher in gastric stromal tumor tissue than in peritumoral tissue and gastric normal tissue. The high expression of PAR-2 may be associated with the invasion and metastasis of gastric stromal tumor.

Reactivation of microRNA-506 inhibits gastric carcinoma cell metastasis through ZEB2.

MicroRNAs (miRNAs) are frequently dysregulated in a variety of human cancers, including gastric carcinoma. To improve our understanding of the role of miRNAs in gastric carcinoma and potential identify novel biomarkers or therapeutic agents, we performed microarray analysis to identify differentially expressed miRNAs in gastric carcinoma, compared with paired non-cancerous gastric tissues. We identified significantly differentially expressed miRNAs in gastric carcinoma tissues, including miR-506. We validated the microarray results by quantitative reverse transcription polymerase chain reaction in 26 specimens and confirmed significant downregulation of miR-506 in gastric carcinoma. Bioinformatics analysis predicted ZEB2 (zinc finger E-box-binding homeobox 2) as a potential target of miR-506. MiR-506 levels and ZEB2 levels were inversely correlated in gastric carcinoma, and low miR-506 levels in gastric carcinoma were associated with poor prognosis. Overexpression of miR-506 in gastric carcinoma cells significantly inhibited cell migration and invasion, while depletion of miR-506 in gastric carcinoma cells significantly increased cell migration and invasion. Transplantation of miR-506-overexpressing gastric carcinoma cells developed significantly smaller tumor, compared to the control. Thus, our results suggest that miR-506 may function as a tumor suppressor and targets and inhibits ZEB2 in gastric carcinoma.

Expression of tissue factor pathway inhibitor-2 in gastric stromal tumor and its clinical significance.

The aim of this study was to explore the expression of tissue factor pathway inhibitor-2 (TFPI-2) in gastric stromal tissue and its clinical significance. TFPI-2 expression was detected by immunohistochemical analysis, RT-PCR and western blotting in tumor, peritumoral and gastric normal tissues from 72 patients with gastric stromal tumors. The level of TFPI-2 expression was observed to be significantly higher in gastric normal tissue than in peritumoral tissue, and was significantly higher in peritumoral tissue than in tumor tissue (P<0.01). As the NIH grade increased, the level of TFPI-2 expression decreased (P<0.01). A low expression level of TFPI-2 was closely associated with invasion and metastasis of gastric stromal tumors. In conclusion, the level of TFPI-2 expression was higher in gastric normal tissue than in gastric stromal tumors. Low expression levels of TFPI-2 may be associated with invasion and metastasis of gastric stromal tumors.