Circ_0000043 promotes the proliferation, migration, invasiveness, and epithelial-mesenchymal transition in breast cancer cells via the miR-136-Smad3 axis

Circular RNA-mediated miRNA sponge & RNA binding protein in biological modulation of breast cancer

Circular RNAs (circRNAs) and small non-coding RNAs of the head-to-junction circle in the construct play critical roles in gene regulation and are significantly associated with breast cancer (BC). Numerous circRNAs are potential cancer biomarkers that may be used for diagnosis and prognosis. Widespread expression of circRNAs is regarded as a feature of gene expression in highly diverged eukaryotes. Recent studies show that circRNAs have two main biological modulation models: sponging and RNA-binding. This review explained the biogenesis of circRNAs and assessed emerging findings on their sponge function and role as RNA-binding proteins (RBPs) to better understand how their interaction alters cellular function in BC. We focused on how sponges significantly affect the phenotype and progression of BC. We described how circRNAs exercise the translation functions in ribosomes. Furthermore, we reviewed recent studies on RBPs, and post-protein modifications influencing BC and provided a perspective on future research directions for treating BC.

Circ_0001982 aggravates breast cancer development through the circ_0001982-miR-144-3p-GSE1 axis

This study was designed to explore the role of circ_0001982 in breast cancer (BC) development. Quantitative real-time polymerase chain reaction and western blot analysis assays were used to determine circ_0001982, miR-144-3p, and gse1 coiled-coil protein (GSE1) expression. Functional assays were performed to evaluate cell proliferation, apoptosis, migration, and invasion. The glycolysis was analyzed with commercial kits. Dual-luciferase reporter assay and RNA immunoprecipitation assays were conducted to analyze the relationships among circ_0001982, miR-144-3p, and GSE1. A murine xenograft model assay was performed to determine circ_0001982-induced effects on BC cell tumor properties in vivo. Circ_0001982 expression was upregulated, but miR-144-3p was reduced in BC tissues and cells in comparison with normal breast tissues and normal human mammary epithelial cells. Circ_0001982 knockdown or miR-144-3p overexpression inhibited BC cell proliferation, glycolysis, migration and invasion, and promoted apoptosis. Circ_0001982 sponged miR-144-3p and negatively regulated miR-144-3p expression in BC cells. In addition, GSE1 was identified as a target mRNA of miR-144-3p. Ectopic GSE1 expression relieved circ_0001982 depletion-induced effects on BC cell tumor properties. Furthermore, circ_0001982 absence suppressed BC cell tumor properties in vivo. Circ_0001982 contributed to the BC cell tumor properties by regulating the miR-144-3p-GSE1 axis.

The Regulation Network and Clinical Significance of Circular RNAs in Breast Cancer

Breast cancer is one of the most common malignant tumors in women worldwide. Circular RNA (circRNA) is a class of structurally stable non-coding RNA with a covalently closed circular structure. In recent years, with the development of high-throughput RNA sequencing, many circRNAs have been discovered and have proven to be clinically significant in the development and progression of breast cancer. Importantly, several regulators of circRNA biogenesis have been discovered. Here, we systematically summarize recent progress regarding the network of regulation governing the biogenesis, degradation, and distribution of circRNAs, and we comprehensively analyze the functions, mechanisms, and clinical significance of circRNA in breast cancer.

Regulation of cell signaling pathways by circular RNAs and microRNAs in different cancers: Spotlight on Wnt/β-catenin, JAK/STAT, TGF/SMAD, SHH/GLI, NOTCH and Hippo pathways

Groundbreaking discoveries in molecular oncology have leveraged our understanding altogether to a new level. Mapping of plethora of cell signaling pathways has enabled researchers to drill down deep into the intermeshed regulatory networks which crosstalk to promote carcinogenesis and metastasis. More importantly, discovery of non-coding RNAs has added new layers of complexity to already complicated nature of cell signaling pathways. The discovery of circular RNAs (circRNAs) has opened the door to an ever-widening understanding of cellular processes that are controlled or influenced by circRNAs. In this review, we have summarized most recent advancements in our understanding related to interplay between circular RNAs and microRNAs for the regulation of NOTCH, Wnt/β-catenin, Hippo, SHH/GLI, JAK/STAT and TGF/SMAD pathways in different cancers.

Integrated study of miR-215 promoting breast cancer cell apoptosis by targeting RAD54B

Background

MicroRNAs (miRNAs) are widely distributed in cells and participate in the regulation of the pathophysiological process of many diseases. As an important part of non‐coding RNA, miRNAs regulate a variety of molecules and signal pathways in tumour cells. However, the evidence for regulatory mechanisms of specific miRNAs in tumour cells is still lacking.

Methods

In this study, we used transcriptomics analysis and integrated a variety of public databases to screen miRNAs that have key regulatory effects on breast cancer (BC). In addition, we used in vitro and in vivo studies and combined clinical samples to verify its regulatory mechanism.

Results

We found that among the specific miRNAs, miR‐215‐5p is a key regulator in BC. Compared with normal adjacent tissues, miR‐215‐5p has a lower expression level in BC tissues. Patients with high expression levels of miR‐215‐5p have a longer survival time. miR‐215‐5p can specifically target the 3′UTR region of RAD54B mRNA and down‐regulate the expression of RAD54B, thereby inhibiting the proliferation of BC cells and promoting the apoptosis of BC cells.

Conclusions

Finally, we found that miR‐215‐5p can be used as an important biomarker for BC. We have clarified its function and revealed its mechanism of targeting RAD54B mRNA for the first time. This may provide important clues to reveal the deeper molecular regulation mechanism of BC.