CircRNA circPDSS1 promotes the gastric cancer progression by sponging miR-186-5p and modulating NEK2.

The aim of this study is to investigate the regulatory mechanism of circPDSS1/miR-186-5p/NEK2 axis on the viability and proliferation in gastric cancer (GC) cell line. Differentially expressed circRNAs, miRNAs, and mRNAs in GC tissues and paracarcinoma tissues were analyzed using gene chips GSE83521, GSE89143, and GSE93415. Then, the expression of circPDSS1, miR-186-5p, and NEK2 was analyzed via quantitative real-time polymerase chain reaction (qRT-PCR). Survival analysis was adopted to explore the association between the circPDSS1 expression and the prognosis of GC. The effect of circPDSS1 on GC cell cycle and apoptosis was verified with the flow cytometry. Targeting relationships among circPDSS1, miR-186-5p, and NEK2 were predicted via bioinformatics analysis and demonstrated by the dual-luciferase reporter assay. Our results showed that circPDSS1 and NEK2 were high-expressed whereas miR-186-5p was low-expressed in GC tissues and cells. CircPDSS1 promoted GC cell cycle and inhibited apoptosis by sponging miR-186-5p, while miR-186-5p inhibited cell cycle and promoted apoptosis by targeting NEK2. Thus, circPDSS1 acts as a tumor promoter by regulating miR-186-5p and NEK2, which could be a potential biomarker and therapeutic target for the management of GC.

Ouyang Y ，Li Y ，Huang Y ，Li X ，Zhu Y ，Long Y ，Wang Y ，Guo X ，Gong K ... -  《-》

Depletion of circPDSS1 inhibits ITGA11 production to confer cisplatin sensitivity through miR-515-5p in gastric cancer.

Wang Y ，Tang S ，Li L ，Sun C ，Liu Y ，Zhao Y ... -  《-》

Circ_0000267 promotes gastric cancer progression via sponging MiR-503-5p and regulating HMGA2 expression.

Circular RNAs (circRNAs) are a class of newly discovered RNAs that attach great importance to modulate gene expression and biological function. Nonetheless, in gastric cancer (GC), the expression and function of circRNA are much less explored. In this study, circ_0000267 expression in GC was investigated and the function and mechanism of circ_0000267 was probed. Quantitative real-time PCR (qRT-PCR) was employed to detect circ_0000267, miR-503-5p, and HMGA2 expression. Immunohistochemistry and western blot were adopted to detect HMGA2 and epithelial-mesenchymal transition (EMT)-related proteins (E-cadherin and N-cadherin) expression in GC tissues and cells, respectively. GC cell lines with circ_0000267 overexpressed and knocked down were constructed, and CCK-8 assay, BrdU assay, scratch healing assay, and transwell assay were employed to assess the effect of circ_0000267 on the proliferation and metastasis of GC cells. Besides, dual-luciferase reporter gene assay was adopted to verify the targeting relationship between circ_0000267 and miR-503-5p. Circ_0000267 showed a significant upregulation in GC tissues and cell lines, and its high expression level was extremely linked to the increased tumor diameter and local lymph node metastasis. Circ_0000267 overexpression accelerated GC cell proliferation, metastasis, and EMT processes, while knocking down circ_0000267 led to the opposite effect. From the perspective of mechanism, circ_0000267 promoted the progression of GC through adsorbing miR-503-5p and upregulating HMGA2 expression. Circ_0000267 is an oncogenic circRNA that affects the progression of GC, which participates in promotion of GC proliferation, migration, invasion, and EMT via modulating the miR-503-5p/HMGA2 axis.

Cai X ，Nie J ，Chen L ，Yu F ... -  《Molecular Genetics & Genomic Medicine》

Identification and Expression of Several Circular RNAs and Knockdown of hsa_circ_0005556 Exerts Oncogenic Functions by miR-767-5p in Gastric Cancer.

Geng H ，Li K ，Pan Q ，Tao S ，Li C ，Zhao H ，Zhao X ... -  《MEDICAL SCIENCE MONITOR》

circ-CEP85L suppresses the proliferation and invasion of gastric cancer by regulating NFKBIA expression via miR-942-5p.

The expression pattern and role of circular RNAs (circRNAs) in the pathogenesis of gastric cancer (GC) and their underlying mechanisms remain unresolved. In this study, we identified differentially expressed circRNAs by a circRNA microarray and verified the results by quantitative reverse transcription-polymerase chain reaction using 117 clinical samples. Cell Counting Kit-8, wound healing, Transwell, and tumorsphere formation assays were conducted to assess the effects of circ-CEP85L on cell proliferation and invasion in vitro. Mouse intraperitoneal injection models were used to assess the functions of circ-CEP85L in vivo. Luciferase reporter assays, fluorescence in situ hybridization, and rescue experiments were performed to elucidate the underlying mechanism of circ-CEP85L. We found that circ-CEP85L, which has not been studied in GC, was significantly downregulated in GC tissues and that decreased circ-CEP85L expression correlated significantly with a worse prognosis. The knockdown of circ-CEP85L promoted the proliferation and invasion of GC cells, which was reversed by overexpression of circ-CEP85L. Furthermore, inhibition of circ-CEP85L promoted tumor growth in vivo. Mechanistically, circ-CEP85L was confirmed to be a direct target of miR-942-5p. In addition, rescue experiments indicated that circ-CEP85L is able to inhibit the proliferation and invasion of GC cells by sponging miR-942-5p. Finally, western blot assays verified that the downregulation of miR-942-5p efficiently reversed the inhibition of NFKBIA induced by circ-CEP85L overexpression. Therefore, we conclude that circ-CEP85L promotes NFKBIA expression by acting as a sponge of miR-942-5p; thus, inhibiting GC proliferation and invasion. circ-CEP85L is a potential target in the treatment of GC.

Lu J ，Wang YH ，Huang XY ，Xie JW ，Wang JB ，Lin JX ，Chen QY ，Cao LL ，Huang CM ，Zheng CH ，Li P ... -  《-》