Circ_0001982 accelerates the progression of colorectal cancer via sponging microRNA-144

Circ_0001982 Up-regulates the Expression of E2F1 by Adsorbing miR-1205 to Facilitate the Progression of Glioma

This study was aimed at probing into the regulatory effects of circular RNA (circRNA)_0001982 on glioma cell proliferation, migration, invasion, and cell cycle, and its underlying mechanism. CircRNA expression profile of glioma tissues/normal brain tissues was downloaded from the Gene Expression Omnibus (GEO) database and analyzed. Circ_0001982, microRNA (miRNA, miR)-1205, and E2F transcription factor 1 (E2F1) expressions in glioma tissues and cell lines were quantified using quantitative real-time polymerase chain reaction (qRT-PCR) and/or Western blot. Glioma cell proliferation, migration, invasion, and cell cycle were detected employing cell counting kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EdU), scratch-healing, Transwell, and flow cytometry assays, respectively. The targeting relationships between miR-1205 and circ_0001982, and miR-1205 and E2F1 3'UTR were verified using bioinformatics, dual-luciferase reporter experiments, and RNA immunoprecipitation (RIP) assay. Pearson's correlation analysis was applied to detect the correlations among circ_0001982, miR-1205, and E2F1 expression levels. Circ_0001982 expression level was increased in glioma tissues and correlated with larger tumor size. Circ_0001982 overexpression enhanced glioma cell proliferation, migration, and invasion, and accelerated cell cycle progression while knocking down circ_0001982 exerted opposite effects. Circ_0001982 directly targeted miR-1205, and miR-1205 directly targeted E2F1. Besides, circ_0001982 could up-regulate E2F1 expression via repressing miR-1205 expression. Circ_0001982 accelerates glioma progression by modulating the miR-1205/E2F1 axis.

Non-Coding RNAs in Colorectal Cancer: Their Functions and Mechanisms

Colorectal cancer (CRC) is a common malignancy with high mortality. However, the molecular mechanisms underlying CRC remain unclear. Controversies over the exact functions of non-coding RNAs (ncRNAs) in the progression of CRC have been prevailing for multiple years. Recently, accumulating evidence has demonstrated the regulatory roles of ncRNAs in various human cancers, including CRC. The intracellular signaling pathways by which ncRNAs act on tumor cells have been explored, and in CRC, various studies have identified numerous dysregulated ncRNAs that serve as oncogenes or tumor suppressors in the process of tumorigenesis through diverse mechanisms. In this review, we have summarized the functions and mechanisms of ncRNAs (mainly lncRNAs, miRNAs, and circRNAs) in the tumorigenesis of CRC. We also discuss the potential applications of ncRNAs as diagnostic and prognostic tools, as well as therapeutic targets in CRC. This review details strategies that trigger the recognition of CRC-related ncRNAs, as well as the methodologies and challenges of studying these molecules, and the forthcoming clinical applications of these findings.

Circ-RNF111 aggravates the malignancy of gastric cancer through miR-876-3p-dependent regulation of KLF12

Background

The aberrant expression of circular RNAs (circRNAs) plays vital roles in the advancement of human cancers, including gastric cancer (GC). In this study, the functions of circRNA ring finger protein 111 (circ-RNF111) in GC were investigated.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) assay was performed for the levels of circ-RNF111, microRNA-876-3p (miR-876-3p) and krueppel-like factor 12 (KLF12) mRNA. RNase R assay was conducted for the feature of circ-RNF111. Cell Counting Kit-8 (CCK-8) assay, colony formation assay, wound-healing assay, and transwell assay were applied for cell viability, colony formation, migration, and invasion, respectively. Flow cytometry analysis was used to analyze cell apoptosis and cell cycle process. The glycolysis level was examined using specific commercial kits. Western blot assay was carried out to measure the protein levels of hexokinase 2 (HK-2) and KLF12. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were employed to verify the combination between miR-876-3p and circ-RNF111 or KLF12. Murine xenograft model was constructed for the role of circ-RNF111 in vivo. Immunohistochemistry (IHC) was used for KLF12 level.

Results

Circ-RNF111 was higher expressed in GC tissues and cells than normal tissues and cells. Silencing of circ-RNF111 restrained cell viability, colony formation, migration, invasion, cell cycle process and glycolysis and induced apoptosis in GC cells in vitro. Circ-RNF111 positively regulated KLF12 expression via absorbing miR-876-3p. MiR-876-3p downregulation reversed the impacts of circ-RNF111 silencing on GC cell malignant phenotypes. MiR-876-3p overexpression repressed GC cell growth, metastasis and glycolysis, inhibited apoptosis and arrested cell cycle, while KLF12 elevation weakened the effects. Besides, circ-RNF111 knockdown inhibited tumor growth in vivo.

Conclusion

Circ-RNF111 knockdown relieved the development of GC by regulating miR-876-3p/KLF12 axis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02373-5.

Hsa_circ_0001982 promotes the progression of breast cancer through miR-1287-5p/MUC19 axis under hypoxia

Background

Breast cancer (BC) is the most commonly malignant tumor among women worldwide. Many studies have reported that circular RNAs (circRNAs) were participated in the regulation of multiple cancers development. However, the mechanism underlying hsa_circ_0001982 in breast cancer development is still unclear.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the levels of circ_0001982, microRNA-1287-5p (miR-1287-5p), and mucin 19 (MUC19) in BC tissues and cells under hypoxia. Moreover, glycolysis was evaluated by glucose consumption, lactic acid production, and hexokinase II (HK2) protein levels. The protein levels of cyclin D1, proliferating cell nuclear antigen (PCNA), and HK2 were determined by western blot assay. Cell proliferation, migration, and invasion were assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-h-tetrazolium bromide (MTT) and transwell assays, respectively. The relationship between miR-1287-5p and circ_0001982 or MUC19 was predicted using starbase v3.0 or Targetscan, and verified by dual-luciferase reporter assay and RNA binding protein immunoprecipitation (RIP) assay. The xenograft model in nude mice was established to examine the effect of circ_0001982 in vivo.

Results

The levels of circ_0001982 and MUC19 were upregulated, while miR-1287-5p was downregulated in BC tissues and cells under hypoxia. Knockdown of circ_0001982 hindered glycolysis, cell viability, migration, and invasion of BC cells under hypoxia. Mechanistic studies discovered that circ_0001982 could act as a sponge for miR-1287-5p to enhance MUC19 expression in BC cells. In addition, circ_0001982 silencing reduced xenograft tumor growth by regulating miR-1287-5p/MUC19 axis.

Conclusion

Circ_0001982 affected BC cells glycolysis, proliferation, migration, and invasion through miR-1287-5p/MUC19 axis under hypoxia.