Circular RNA ZFR promotes cell cycle arrest and apoptosis of colorectal cancer cells via the miR-147a/CACUL1 axis

Abstract

Background: Colorectal cancer (CC) is one of the most prevalent malignancies worldwide. Nonetheless, its pathogenicity and molecular mechanisms have not been completely elucidated yet. The potential clinical value of circular RNAs (circRNAs) in tumor diagnosis, treatment, and prognosis has received considerable attention. Methods: Here, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) examined the levels of circular ZFR (circZFR) in CC cells. The expression of circZFR was knocked down in CC cells and cell viability was detected using Cell Counting Kit-8 (CCK-8) and colony formation assays. Cell cycle progression was assessed by flow cytometry and the expression levels of cyclin-associated proteins were detected by western blot analysis. The transferase dUTP nick end labeling (TUNEL) assay was used to detect apoptosis and western blot analysis was used to evaluate the expression levels of apoptosis-associated proteins. Subsequently, the interactions between circZFR and microRNA (miR)-147a and between miR-147a and CDK2 associated cullin domain 1 (CACUL1) were predicted by the Encyclopedia of RNA Interactomes database and verified by luciferase reporter assays. Finally, plasmid transfection, CCK-8, and flow cytometry assays were used to explore the associated mechanism of action. Results: CircZFR was highly expressed in CC cell lines. Interference with its expression inhibited proliferation and induced G1/S cell cycle arrest and apoptosis in CC cells. The expression levels of miR-147a and CACUL1 were decreased and increased, respectively, in CC cells. These data demonstrated that circZFR could target miR-147a and CACUL1 to regulate the cell cycle and apoptosis of CC cells and, ultimately, promote the progression of CC. Conclusions: Knockdown of the expression of circZFR upregulated miR-147a expression and reduced CACUL1 expression levels, thereby inhibiting the proliferation of CC cells and inducing cell cycle arrest and apoptosis.

Biological landscape and nanostructural view in development and reversal of oxaliplatin resistance in colorectal cancer

“…The generation of circRNAs can be mediated by exon skipping and direct back-splicing that their structure is a closed loop and lacks polyadenylated tail [ [159] , [160] , [161] ]. Recent studies have demonstrated important function of circRNAs in CRC [ [162] , [163] , [164] ]. Circ-0079662 has been associated with development of OXA resistance in CRC due to sponging miR-324-5p to increase HOXA9 expression [ 165 ].…”

Circular RNAs in Cell Cycle Regulation of Cancers

“…Employing a similar approach, circZFR represses miR-147a to abrogate the inhibitory effect on CDK2-associated cullin domain 1 (CACUL1). Consequently, the increased expression of CDK2, CDK4, CDK6, and cyclin D1 is then conveyed by CACUL [ 103 ].…”

A Meta-Analysis of the Prognostic and Clinicopathological Significance of circZFR in Human Gastrointestinal Cancers

“…Circular RNA zinc finger RNA-binding protein (Circ-ZFR) is a transcription product of zinc finger RNA-binding protein (ZFR) gene mapped to chromosome 5p13.3. Studies of gastrointestinal (GIT) cancers have shown that it could be involved in the development and progression of various GIT cancers such as hepatocellular carcinoma (HCC) [14], gastric cancer (GC) [15], and colorectal cancer (CRC) [16] among others. While the majority of these studies have demonstrated its oncogenic property, their small sample sizes limit their clinical significance.…”