Circ_0003356 suppresses gastric cancer growth through targeting the miR-668-3p/SOCS3 axis

BACKGROUND Circular RNAs(circRNAs)have attracted extensive attention as therapeutic targets in gastric cancer(GC).Circ_0003356 is known to be downregulated in GC tissues,but its cellular function and mechanisms remain undefined.AIM To investigate the role of circ_0003356 in GC at the molecular and cellular level.METHODS Circ_0003356,miR-668-3p,and SOCS3 expression were assessed via quantitative real time-polymerase chain reaction(qRT-PCR).Wound healing,EdU,CCK-8,flow cytometry and transwell assays were used to analyze the migration,proliferation,viability,apoptosis and invasion of GC cells.The subcellular localization of circ_0003356 was monitored using fluorescence in situ hybridization.The interaction of circ_0003356 with miR-668-3p was confirmed using RIP-qRT-PCR,RNA pull-down,and dual luciferase reporter assays.We observed protein levels of genes via western blot.We injected AGS cells into the upper back of mice and performed immunohistochemistry staining for examining E-cadherin,N-cadherin,Ki67,and SOCS3 expressions.TUNEL staining was performed for the assessment of apoptosis in mouse tumor tissues.RESULTS Circ_0003356 and SOCS3 expression was downregulated in GC cells,whilst miR-668-3p was upregulated.Exogenous circ_0003356 expression and miR-668-3p silencing suppressed the migration,viability,proliferation,epithelial to mesenchy-mal transition(EMT)and invasion of GC cells and enhanced apoptosis.Circ_0003356 overexpression impaired tumor growth in xenograft mice.Targeting of miR-668-3p by circ_0003356 was confirmed through binding assays and SOCS3 was identified as a downstream target of miR-668-3p.The impacts of circ_0003356 on cell proliferation,apoptosis,migration,invasion and EMT were reversed by miR-668-3p up-regulation or SOCS3 downregulation in GC cells.CONCLUSION Circ_0003356 impaired GC development through its interaction with the miR-668-3p/SOCS3 axis.

Dihydromyricetin-mediated inhibition of the Notch1 pathway induces apoptosis in QGY7701 and Hep G2 hepatoma cells

AIM To investigate whether Dihydromyricetin(DHM) inhibits cell proliferation and promotes apoptosis by downregulating Notch1 expression.METHODS The correlation between Notch1 and Hes1(a Notch1 target molecule) expression in hepatoma samples was confirmed by q RT-PCR. In addition, MTT assays, flow cytometry and TUNEL analysis showed that DHM possessed strong anti-tumor properties, evidenced not only by reduced cell proliferation but also by enhanced apoptosis in QGY7701 and Hep G2 hepatocellular carcinoma(HCC) cells. The expressions of Notch1, Hes1, Bcl-2 and Bax were determined by Western blot.RESULTS Among the tested samples(n = 64), the expression levels of Notch1(75% of patients) and Hes1(79.7% of patients) m RNA in tumor tissues were higher than in the normal liver tissues. There was a negative correlation between the expression of Notch1 and the degree of differentiation and positively correlated with the Alpha Fetal Protein concentration. The viability of HCC cells treated with DHM was significantly inhibited in a dose and time-dependent manner. Apoptosis was induced in Hep G2 and QGY7701 cell lines following 24 h of DHM treatment. After treatment with DHM, the protein expression of Notch1 was downregulated, the apoptosis-related protein Bax was upregulated and Bcl2 was downregulated. Notch1 si RNA further enhanced the anti-tumor properties of DHM. CONCLUSION Notch1 is involved in the development of HCC and DHM inhibits cell proliferation and promotes apoptosis by down-regulating the expression of Notch1.