Hsa_circ_0003356 suppresses gastric cancer progression via miR-556-5p/FKBP5 axis

BACKGROUND

CircRNAs are implicated in the tumorigenesis of various human cancers. This study aims to explore how circ_0003356 contributes to the development of gastric cancer (GC).

METHODS

Circ_0003356 expression was analyzed in GSE184882 dataset and validated in our cohort of GC patients and human GC cell lines. The correlations between circ_0003356 levels and prognostic parameters were analyzed. The contribution of circ_0003356 in GC cell malignant behaviors such as cell survival, apoptosis and invasion were investigated by circ_0003356 overexpression in GC cell lines. The downstream targets of circ_0003356 were predicted and verified in vitro and in vivo. The in vivo function of circ_0003356 was studied as well in a xenograft mouse model.

RESULTS

Circ_0003356 expressed at a low level in human GC tissues and cells, which was closely associated with poor outcome of GC patients. Circ_0003356 overexpression induced GC cell apoptosis while depressed the growing, migration and invasive abilities through miR-556-5p/FKBP5 axis. In vivo model showed retarded tumor growth when circ_0003356-overexpressed cells were inoculated.

CONCLUSION

Circ_0003356 is identified as a potential biomarker of the prognosis of human gastric cancer, and circ_0003356/miR-556-5p/FKBP5 axis could be a promising target in gastric cancer treatment.

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 down-regulation in GC cells.

CONCLUSION

Circ_0003356 impaired GC development through its interaction with the miR-668-3p/SOCS3 axis.