CircFAM64A enhances cellular processes in triple-negative breast cancer by targeting the miR-149-5p/CDT1 axis

The therapeutic potential of circular RNA in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is among the most aggressive subtypes of the disease that does not express estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. Circular RNAs (circRNAs) are a type of non-coding RNA with a circular shape formed by non-standard splicing or reverse splicing. Numerous circRNAs exhibit abnormal expression in various malignancies, showing their critical role in the emergence and growth of tumors. Recent studies have shown evidence supporting the idea that certain circRNAs regulate the proliferation and metastasis of TNBC. In addition, circRNAs alter metabolism and the immune microenvironment to promote or inhibit the development of TNBC. Notably, circRNAs may affect the efficacy of clinical drug therapy, serve as therapeutic targets, and be used as molecular biomarkers in the future. Herein, we will first summarize the biogenesis and function of circRNAs. Then, we will explain current research on circRNAs related to TNBC and their potential to serve as therapeutic targets or biomarkers for future drug development, providing a new direction and idea for TNBC therapy.

Circular RNAs in Breast Cancer: An Update

Breast cancer (BC), characterized by high heterogeneity, is the most commonly reported malignancy among females across the globe. Every year, many BC patients die owing to delayed diagnosis and treatment. Increasing researches have indicated that aberrantly expressed circular RNAs (circRNAs) are implicated in the tumorigenesis and progression of various tumors, including BC. Hence, this article provides a summary of the biogenesis and functions of circRNAs, as well as an examination of how circRNAs regulate the progression of BC. Moreover, circRNAs have aroused incremental attention as potential diagnostic and prognostic biomarkers for BC. Exosomes enriched with circRNAs can be secreted into the tumor microenvironment to mediate intercellular communication, affecting the progression of BC. Detecting the expression levels of exosomal circRNAs may provide reference for BC diagnosis and prognosis prediction. Illuminating insights into the earlier diagnosis and better treatment regimens of BC will be potentially available following elucidation of deeper regulatory mechanisms of circRNAs in this malignancy.

Circular forms of dedicator of cytokinesis 1 promotes breast cancer progression by derepressing never in mitosis related kinase 2 via sponging miR-128-3p

The conjecture of breast cancer is uncertain because of its explosive growth and the complicated molecular mechanisms. Circular RNAs (circRNAs) are regulatory RNA sequences present in the genome and their regulatory mechanism involves the sponging of microRNAs (miRNAs). In this study, we explored the regulation between circular forms of dedicator of cytokinesis 1 (circDOCK1) (hsa_circ_0007142) and miR-128-3p, and its implication on the pathogenesis of breast cancer modulated by never in mitosis (NIMA) related kinase 2 (NEK2). We revealed an increase in circDOCK1 and NEK2 expression, and a decrease in miR-128-3p expression in breast cancer tissues and cell lines. Bioinformatics analysis and experimental validation indicated a positive correlation between circDOCK1 and NEK2 expression but a negative correlation was recorded between miR-128-3p and circDOCK1 or NEK2, respectively. Furthermore, inhibition of circDOCK1 expression was followed by an increase in miR-128-3p and a decrease in NEK2 levels in vitro and in vivo. The luciferase assay concluded that miR-128-3p was a direct target of circDOCK1 while NEK2 was the direct target of miR-128-3p. Furthermore, circDOCK1 inhibition hindered breast cancer development by repressing NEK2 and thus promoting the increased expression of miR-128-3p both in vitro and in vivo. We therefore conclude that circDOCK1 promotes breast cancer progression by targeting miR-128-3p-mediated downregulation of NEK2 and that the circDOCK1/hsa-miR-128-3p/NEK2 axis may be a novel therapeutic target for breast cancer treatment.

Hsa_circ_0008500 inhibits apoptosis of adipose-derived stem cells under high glucose through hsa-miR-1273h-5p/ELK1 axis

Preliminary researches have confirmed that the number of apoptosis of adipose tissue-derived stem cells (ADSCs) in patients with diabetes is significantly increased, leading to a difficult healing wound. Increasing researches revealed that circular RNAs (circRNAs) can control apoptosis. However, it is still unclear whether and how circRNAs are critical for regulating ADSCs apoptosis. In this study, we utilized in vitro model in which ADSCs were cultivated with normal glucose (NG) (5.5 mM) or high glucose (HG) (25 mM) medium, respectively, and found that more apoptotic ADSCs were observed in HG medium comparing to ADSCs in NG medium. Furthermore, we found that hsa_circ_0008500 attenuated HG-mediated ADSCs apoptosis. In addition, Hsa_circ_0008500 could directly interact with hsa-miR-1273h-5p, acting as a miRNA sponge, which subsequently suppressed Ets-like protein-1(ELK1) expression, the downstream target of hsa-miR-1273h-5p. Thus, these results indicated that targeting the hsa_circ_0008500/hsa-miR-1273h-5p/ELK1 signaling pathway in ADSCs may be a potential target for repairing diabetic wounds.

Crocin suppresses breast cancer cell proliferation by down-regulating tumor promoter miR-122-5p and up-regulating tumor suppressors FOXP2 and SPRY2

Crocin has been reported to have antitumor activity in several tumors including breast cancer. Nevertheless, the mechanism of action of crocin on breast cancer remains unclear. The cytotoxicity of crocin was evaluated by CCK-8 assay. Cell proliferation was assessed using EdU incorporation assay and western blot analysis. Breast cancer-related genes were extracted from GEPIA. miR-122-5p targets were predicted using Targetscan, starbase, and miRDB softwares. Luciferase reporter assay was employed to confirm whether miR-122-5p targeted sprouty2 (SPRY2) and forkhead box P2 (FOXP2). Results showed that crocin exhibited cytotoxicity and suppressed the proliferation in breast cancer cells. miR-122-5p was upregulated in breast cancer tissues and cells. Crocin suppressed miR-122-5p to block the proliferation of breast cancer cells. Seven targets of miR-122-5p were identified in breast cancer. SPRY2 and FOXP2 were selected for further experiments due to their involvement in breast cancer. miR-122-5p targeted SPRY2 and FOXP2 to inhibit their expression. miR-122-5p knockdown restrained breast cancer cell proliferation by targeting SPRY2 and FOXP2. Additionally, crocin increased SPRY2 and FOXP2 expression by inhibiting miR-122-5p expression. Together, our results suggested that crocin inhibited proliferation of breast cancer cells through decreasing miR-122-5p expression and the subsequent increase of SPRY2 and FOXP2 expression.

Tumor-Suppressive and Oncogenic Roles of microRNA-149-5p in Human Cancers

Malignant tumors are always a critical threat to human health, with complex pathogenesis, numerous causative factors, and poor prognosis. The features of cancers, such as gene mutations, epigenetic alterations, and the activation and inhibition of signaling pathways in the organism, play important roles in tumorigenesis and prognosis. MicroRNA (miRNA) enables the control of various molecular mechanisms and plays a variety of roles in human cancers, such as radiation sensitivity and tumor immunity, through the regulation of target genes. MiR-149-5p participates in the process and is closely related to lipogenesis, the migration of vascular endothelial cells, and the expression of stem-cell-related proteins. In recent years, its role in cancer has dramatically increased. In this review, we summarize the regular physiological roles of miRNAs, specifically miR-149-5p, in the organism and discuss the tumor-suppressive or oncogenic roles of miR-149-5p in different human cancers with respect to signaling pathways involved in regulation. Possible clinical applications of miR-149-5p in future targeted therapies and prognosis improvement in oncology are suggested.

Circular RNAs as novel biomarkers in triple-negative breast cancer: a systematic review

More effective prognostic and diagnostic tools are urgently required for early detecting and treating triple-negative breast cancer, which is the most acute type of breast cancer because of its lower survival rate, aggressiveness, and non-response to various common treatments. So, it remains the most harmful malignancy for women worldwide. Recently, circular RNAs, as a group of non-coding RNAs, with covalently closed loop and high stability have been discovered, which can modulate gene expression through competing with endogenous microRNA sponges. This finding provided further insight into novel approaches for controlling genes affected in many disorders and malignancies. This review concentrates on the dysregulated expression of circRNAs like their diagnostic and prognostic values in TNBC. This review aims to focus on the abnormal expression of circRNAs and their diagnostic and prognostic values in TNBC. We used PubMed, Embase, and Web of Science databases and ClinicalTrials.gov to systematically search for all relevant clinical studies. This review is based on articles published in databases up to April 2022 with the following keywords: "Circular RNA", "CircRNA", "Triple-Negative Breast Cancer" and "TNBC". We conducted a review of published CircRNA profiled-research articles to identify candidate CircRNA biomarkers for TNBC. The review is registered on JBI at https://jbi.global/systematic-review-register . Accumulating evidence has shown that several circRNAs are downregulated and some are upregulated in TNBC. The results of these studies confirm that circRNAs might be potential biomarkers with the diagnostic, prognostic, and therapeutic target value for TNBC. We also consider the connection between circRNAs and TNBC cell proliferation, apoptosis, metastasis, and chemotherapy resistance and sensitivity.

Bioinformatics Method Was Used to Analyze the Highly Expressed Gene FAM83A of Breast Cancer in Young Women

Objectives

Preliminary analysis of breast cancer related to unknown functional gene FAM83A through bioinformatics knowledge to inform further experimental studies. Select high expression genes for breast cancer and use bioinformatics methods to predict the biological function of FAM83A.

Methods

Genes with significant differences in expression between breast tumors and normal breast tissue libraries were selected from CGAP's SAGE Digital Gene Expression Displayer (DGED) database. An unknown functional gene, FAM83A, which is highly expressed in breast cancer, was screened. We performed an analysis of the gene structure, subcellular localization, physicochemical properties of the encoding products, functional sites, protein structure, and functional domains.

Results

Through SAGE DGED, a total of 185 genes with expression differences were found. The structure and function of FAM83A have ideal predictions, and it is generally determined that this gene encodes a nuclear protein with a nucleoprotein. The active site of PLDc and the functional domain of DUF1669 can be involved in signal transduction and gene expression regulation in tumorigenesis and metastasis. Digital gene representation of the Tumor Genome Project Data Library was used to select differentially expressed genes in breast cancer tissue and breast benign tumor tissue.

Conclusion

Studies show that FAM83A is a potential research target associated with tumorigenesis and metastasis. Initial tests confirmed the expression of this gene. Lay a solid foundation for further research learning. FAM83A is a highly expressed gene in breast cancer and can serve as a target for studying molecular mechanisms in breast cancer.