Circular RNAs: Their Role in the Pathogenesis and Orchestration of Breast Cancer

Abstract

As one of the most frequently occurring malignancies in women, breast cancer (BC) is still an enormous threat to women all over the world. The high mortality rates in BC patients are associated with BC recurrence, metastatic progression to distant organs, and therapeutic resistance. Circular RNAs (circRNAs), belonging to the non-coding RNAs (ncRNAs), are connected end to end to form covalently closed single-chain circular molecules. CircRNAs are widely found in different species and a variety of human cells, with the features of diversity, evolutionary conservation, stability, and specificity. CircRNAs are emerging important participators in multiple diseases, including cardiovascular disease, inflammation, and cancer. Recent studies have shown that circRNAs are involved in BC progress by regulating gene expression at the transcriptional or post-transcriptional level via binding to miRNAs then inhibiting their function, suggesting that circRNAs may be potential targets for early diagnosis, treatment, and prognosis of BC. Herein, in this article, we have reviewed and summarized the current studies about the biogenesis, features, and functions of circRNAs. More importantly, we emphatically elucidate the pivotal functions and mechanisms of circRNAs in BC growth, metastasis, diagnosis, and drug resistance. Deciphering the complex networks, especially the circRNA-miRNA target gene axis, will endow huge potentials in developing therapeutic strategies for combating BC.

Analysis and validation of m6A regulatory network: a novel circBACH2/has-miR-944/HNRNPC axis in breast cancer progression

“…CircRNAs are ubiquitous non-coding RNAs in eukaryotic cells, which are diverse, stable, and evolutionarily conserved. It is gradually recognized that circRNA is dysregulated in BC tissues and participated in the pathogenesis of BC by harboring miRNAs [ 27 ]. For instance, Yang et al successfully identified a total of 47 upregulated and 307 downregulated DE circRNAs to construct the competing endogenous RNA (ceRNA) network of BC [ 28 ].…”

Landscape of the epigenetic regulation in wound healing

“…CircRNAs belong to a large category of endogenous ncRNAs that are structurally connected end to end to form single-chain molecules with a covalently closed loop structure ( He et al, 2021b ). Functionally, circRNAs can regulate the level of transcriptional and post-transcriptional parental genes by acting as miRNA sponges ( Kristensen et al, 2019 ).…”

Current landscape of tumor-derived exosomal ncRNAs in glioma progression, detection, and drug resistance

“…Multiple lncRNAs have been investigated to be involved in the initiation and progression of glioma including CRNDE, H19, XIST, GAS, Malat1, HOTAIR, and SOX2OT [ 11 ]. CircRNAs are covalently closed single-chain circular molecules, which are endogenous molecules that exhibit diversity, evolutionary conservation, relative stability, and specificity [ 12 ]. CircRNAs usually function as tumor promoters or suppressors by acting as miRNA sponges to subsequently regulate transcription and splicing of their parental genes.…”