Circular RNA YAP1 inhibits the proliferation and invasion of gastric cancer cells by regulating the miR-367-5p/p27 Kip1 axis

Circular RNA CircMTO1 Inhibits Proliferation of Glioblastoma Cells via miR-92/WWOX Signaling Pathway

Background

Circular RNA circMTO1 has been reported to inhibit the progression of many types of cancers. However, the role of circMTO1 in the progression of glioblastoma remains unclear. The purpose of our study was to explore the potential involvement of circMTO1 in glioblastoma.

Material/Methods

The expression of circMTO1 in human glioblastoma tissues was determined via quantitative real-time polymerase chain reaction (qRT-PCR). The effect of circMTO1 on proliferation of human glioblastoma cell line U251 was assessed through the Cell Counting Kit-8 (CCK-8) and colony formation assay. The regulatory interaction between circMTO1 and miR-92 was explored by bioinformatics prediction and luciferase reporter assay.

Results

We showed that circMTO1 was markedly downregulated in glioblastoma tissues compared with adjacent normal tissues. Lower circMTO1 level was significantly associated with shorter overall survival among patients with glioblastoma. In addition, circMTO1 inhibited proliferation of cell U251 cells. Mechanistically, circMTO1 upregulates the expression of WWOX in U251 cells, and WWOX mediates circMTO1-induced inhibition of proliferation of U251 cells. In addition, miR-92 downregulates the expression of WWOX by the targeting its mRNA 3′ UTR. More importantly, circMTO1 directly interact with miR-92, and subsequently serves as a miRNA sponge to upregulate WWOX expression.

Conclusions

Our results demonstrate that circMTO1 inhibits the proliferation of glioblastoma cells via the miR-92/WWOX signaling pathway.

MicroRNA-142-3p suppresses endometriosis by regulating KLF9-mediated autophagy in vitro and in vivo

The detailed pathogenesis of endometriosis remains largely unclear despite decades of research. Recent studies have demonstrated that miRNAs plays an important role in endometriosis. The expression of miR-142-3p was decreased in ectopic endometrial tissues, while KLF9 and VEGFA expression levels were increased. Overexpression of miR-142-3p or knockdown of KLF9 significantly suppressed CRL-7566 cell proliferation and metastasis, induced cell apoptosis, and decreased both cell autophagy and vascularization. Additionally, KLF9 was confirmed to be a direct target of miR-142-3p and to directly bind to the promoter of the VEGFA gene, regulating its expression. Finally, intraperitoneal injection of miR-142-3p lentivirus significantly attenuated ectopic endometriotic lesions in vivo.miR-142-3p directly targeted KLF9, regulated VEGFA expression, and was protective against the growth of ectopic endometriotic lesions. Therefore, the miR-142-3p/KLF9/VEGFA signalling pathway may be a potential target in endometriosis treatment.

Circular RNA circHIAT1 inhibits cell growth in hepatocellular carcinoma by regulating miR-3171/PTEN axis

Circular RNAs (circRNAs), a novel subgroup of non-coding RNAs (ncRNAs), have been reported in human cancers due to their significant regulatory roles. CircRNA Hippocampus Abundant Transcript 1 (circHIAT1) has been studied in clear cell renal cell carcinoma. However, whether it can regulate the tumorigenesis of hepatocellular carcinoma (HCC) remains unclear. The expression level of circHIAT1 in HCC samples and cell lines was measured by qRT-PCR analysis. CircHIAT1 was expressed at a significantly low level in cancerous samples. Based on Kaplan-Meier survival analysis, we determined a positive correlation between the downregulation of circHIAT1 and the poor overall survival of HCC patients. Using subcellular fractionation and RNA FISH assay, we identified the predominant cytoplasmic localization of circHIAT1. Both in vitro and in vivo experiments demonstrated the suppressive effect of circHIAT1 on the HCC cell growth. Mechanistically, circHIAT1 acted as the miR-3171 sponge to upregulate PTEN in HCC. Finally, rescue assays demonstrated the role of circHIAT1/miR-3171/PTEN pathway in regulating HCC cell growth. Taken together, this study revealed the novel mechanism of circHIAT1 in HCC.

Non-coding RNAs in regulating gastric cancer metastasis

Gastric cancer is one of the leading causes of cancer-related deaths worldwide, and mortality remains high, especially in East Asia. At present, the main method to diagnose gastric cancer is pathological biopsy. At the time of diagnosis, most patients have been diagnosed with advanced cancer and metastasis. The treatment of gastric cancer patients is mainly radical surgical resection and chemoradiotherapy, while patients with metastatic tumor have great challenges to radical surgery and are prone to drug resistance. Metastasis is an important factor affecting tumor development. In addition, evidence accumulated in the literature indicates that non-coding RNA plays a key role in tumor metastasis. This article reviews the role of ncRNAs in gastric cancer metastasis and discusses the regulatory mechanism in the development and treatment of gastric cancer.

Role of circular RNAs in gastric cancer: Recent advances and prospects

Circular RNA (circRNA) is a newly discovered non-coding RNA with special structure, which is widely expressed in eukaryotic organisms and mainly located in the cytoplasm. circRNAs participate in gene regulation by working as miRNA sponges that block the inhibitory effect of miRNA on its target genes. In addition, circRNAs can bind to RNA binding proteins to regulate gene expression. Based on characteristics of stability, expression specificity and participation in gene regulation, circRNAs are expected to be biomarkers for early diagnosis of cancer or potential targets for cancer therapy. With the help of bioinformatics analysis, circRNA microarray analysis and high-throughput sequencing technology, more circRNAs were discovered to participate in the progression of gastric cancer (GC) over the past three years. This article gives an overview of these recent research focusing on the roles of circRNAs in GC and highlights the advances.

A novel circular RNA hsa_circ_0008035 contributes to gastric cancer tumorigenesis through targeting the miR-375/YBX1 axis

Circular RNAs (circRNAs) play an important regulatory role in a variety of human cancers, including gastric cancer. The mechanisms for the circRNAs in gastric cancers are not fully understood. This study aims to uncover the mechanism by which circRNAs regulate gastric cancer tumorigenesis. Among the microarray data, we screened dysregulated circRNAs and identified an up-regulated circRNA, hsa_circ_0008035. Functionally, the hsa_circ_0008035 silencing by the siRNA transfection inhibited the proliferation and invasion of gastric cancer cells. Mechanically, hsa_circ_0008035 acted as a sponge for the miR-375 and absorbed its expression, and miR-375 was found to target YBX1 3'-UTR, constructing a hsa_circ_0008035/miR-375/YBX1 axis. Taken together, these findings are evidence that circRNA hsa_circ_0008035 promotes gastric cancer cell proliferation and invasion by regulating miR-375/YBX1.

CircDLST promotes the tumorigenesis and metastasis of gastric cancer by sponging miR-502-5p and activating the NRAS/MEK1/ERK1/2 signaling

Background

Accumulating evidence shows that, the dysregulation of circular RNAs (circRNAs) is associated with the progression of multiple malignancies. But, the underlying mechanisms by which has_circ_0032627 (circDLST) contributed to gastric cancer (GC) remain undocumented.

Methods

The expression and cellular localization of circDLST and its association with clinicopathological characteristics and prognosis in patients with GC was analysed by using fluorescence in situ hybridization. Gain- and loss-of-function experiments as well as a subcutaneous xenograft tumor model and a liver metastasis model from orthotopic implantation of GC tissues were conducted to assess the role of circDLST in GC cells. CircDLST specific binding with miR-502-5p was confirmed by dual luciferase gene report, RNA immunoprecipitation (RIP) assays and RIP-miRNA expression profiling. qRT-PCR and Western blot analysis was used to detect the effects of circDLST on miR-502-5p-mediated NRAS/MEK1/ERK1/2 signaling in GC cells.

Results

The expression levels of circDLST were dramatically elevated in GC tissues as compared with the adjacent normal tissues, and acted as an independent prognostic factor of poor survival in patients with GC. Knockdown of circDLST inhibited the cell viability, colony formation, DNA synthesis, cell invasion and liver metastasis in vitro and in vivo, whereas overexpression of circDLST had the opposite effects. Furthermore, circDLST was co-localized with miR-502-5p in the cytoplasm of GC cells, and acted as a sponge of miR-502-3p in GC cells, which abrogated the tumor promoting effects of circDLST by inactivating the NRAS/MEK1/ERK1/2 signaling in GC cells.

Conclusion

CircDLST promotes the tumorigenesis and metastasis of GC cells by sponging miR-502-5p to activate the NRAS/MEK1/ERK1/2 signaling.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-1015-1) contains supplementary material, which is available to authorized users.

Circular RNA circTADA2A promotes osteosarcoma progression and metastasis by sponging miR-203a-3p and regulating CREB3 expression

BACKGROUND

As a subclass of noncoding RNAs, circular RNAs (circRNAs) have been demonstrated to play a critical role in regulating gene expression in eukaryotes. Recent studies have revealed the pivotal functions of circRNAs in cancer progression. However, little is known about the role of circTADA2A, also named hsa_circ_0043278, in osteosarcoma (OS).

METHODS

CircTADA2A was selected from a previously reported circRNA microarray comparing OS cell lines and normal bone cells. QRT-PCR was used to detect the expression of circTADA2A in OS tissue and cell lines. Luciferase reporter, RNA immunoprecipitation (RIP), RNA pull-down and fluorescence in situ hybridization (FISH) assays were performed to confirm the binding of circTADA2A with miR-203a-3p. OS cells were stably transfected with lentiviruses, and Transwell migration, Matrigel invasion, colony formation, proliferation, apoptosis, Western blotting, and in vivo tumorigenesis and metastasis assays were employed to evaluate the roles of circTADA2A, miR-203a-3p and CREB3.

RESULTS

Our findings demonstrated that circTADA2A was highly expressed in both OS tissue and cell lines, and circTADA2A inhibition attenuated the migration, invasion and proliferation of OS cells in vitro as well as tumorigenesis and metastasis in vivo. A mechanistic study revealed that circTADA2A could readily sponge miR-203a-3p to upregulate the expression of CREB3, which was identified as a driver gene in OS. Furthermore, miR-203a-3p inhibition or CREB3 overexpression could reverse the circTADA2A silencing-induced impairment of malignant tumor behavior.

CONCLUSIONS

CircTADA2A functions as a tumor promoter in OS to increase malignant tumor behavior through the miR-203a-3p/CREB3 axis, which could be a novel target for OS therapy.