MicroRNA-1298-5p inhibits the tumorigenesis of breast cancer by targeting E2F1

Emerging roles of CircRNA-miRNA networks in cancer development and therapeutic response

The complex interplay of epigenetic factors is essential in regulating the hallmarks of cancer and orchestrating intricate molecular interactions during tumor progression. Circular RNAs (circRNAs), known for their covalently closed loop structures, are non-coding RNA molecules exceptionally resistant to enzymatic degradation, which enhances their stability and regulatory functions in cancer. Similarly, microRNAs (miRNAs) are endogenous non-coding RNAs with linear structures that regulate cellular biological processes akin to circRNAs. Both miRNAs and circRNAs exhibit aberrant expressions in various cancers. Notably, circRNAs can function as sponges for miRNAs, influencing their activity. The circRNA/miRNA interaction plays a pivotal role in the regulation of cancer progression, including in brain, gastrointestinal, gynecological, and urological cancers, influencing key processes such as proliferation, apoptosis, invasion, autophagy, epithelial-mesenchymal transition (EMT), and more. Additionally, this interaction impacts the response of tumor cells to radiotherapy and chemotherapy and contributes to immune evasion, a significant challenge in cancer therapy. Both circRNAs and miRNAs hold potential as biomarkers for cancer prognosis and diagnosis. In this review, we delve into the circRNA-miRNA circuit within human cancers, emphasizing their role in regulating cancer hallmarks and treatment responses. This discussion aims to provide insights for future research to better understand their functions and potentially guide targeted treatments for cancer patients using circRNA/miRNA-based strategies.

E2F1 Facilitates the Proliferation and Stemness of Gastric Cancer Cells by Activating CDC25B Transcription and Modulating the MAPK Pathway

Gastric cancer (GC) is a health problem that concerns people around the world. CDC25B is an essential cell cycle regulatory factor that is overexpressed in a variety of tumor cells. CDC25B plays a vital part in the progression and proliferation of malignant tumors. However, it is not yet clear that how CDC25B affects the stemness of GC cells. The study used bioinformatics to detect the expression of E2F1 and CDC25B in GC tissues and their correlation, as well as pathways enriched by CDC25B. We detected the expression of E2F1 and CDC25B in GC cell lines using quantitative reverse transcription polymerase chain reaction and tested the combination relationship between E2F1 and CDC25B using chromatin immunoprecipitation (ChIP) and dual-luciferase assays. We measured cell viability using CCK-8 assay, evaluated sphere-forming efficiency using sphere formation assay, and determined cell proliferation ability using colony formation assay. We also analyzed the expression of stemness markers and MAPK pathway-related proteins using western blot. In GC tissues and cells, CDC25B was upregulated. Silencing CDC25B could affect the MAPK pathway, thereby repressing the proliferation and stemness of GC cells. As predicted by bioinformatics, CDC25B had an upstream transcription factor, E2F1, which also had a high expression level in GC. Dual-luciferase and ChIP assays confirmed the combination relationship between the two. Rescue experiments uncovered that overexpression of CDC25B could reverse the impact induced by E2F1 knockdown on proliferation and stemness of cells. In conclusion, E2F1 could activate CDC25B transcription to regulate the MAPK pathway and enhance the proliferation and stemness of GC cells. We revealed a potential regulatory pathway of stemness of GC cells that was mediated by CDC25B, providing new ideas for improving and innovating GC treatment.

LncRNA OSER1-AS1 regulates the inflammation and apoptosis of rheumatoid arthritis fibroblast like synoviocytes via regulating miR-1298-5p/E2F1 axis

It has been reported that long noncoding RNAs (LncRNAs) take part in the progression and occurrence of rheumatoid arthritis (RA). The current work aimed to dig the effect of lncRNA OSER1-AS1 on RA and the associated mechanism. Quantitative real-time polymerase chain reaction (qRT-PCR) was made to decide that OSER1-AS1 was significantly lowly expressed in synovial tissue and serum of RA patients, which was consistent in RA-FLSs cell lines. The result of ROC curve indicated that OSER1-AS1 could be a diagnostic biomarker for RA patients. Cell Counting Kit-8 assay (CCK-8), EdU staining and flow cytometry were performed to explore the effect of OSER1-AS1 on RA-FLSs in vitro. Relative levels of interleukin-1 (IL-1), interleukin-6 (IL-6), matrix metalloproteinases-3 (MMP-3) were detected by ELISA and the result displayed that overexpression of OSER1-AS1 inhibited RA-induced inflammatory production of IL-1, IL-6 and MMP3. Bioinformatics analysis, luciferase reporter, RNA immunoprecipitation assays (RIP) and RNA pull-down assay were conducted to confirm the binding between microRNA-1298-5p (miR-1298-5p) and OSER1-AS1 or E2F transcription factor 1 (E2F1). Mechanistically, OSER1-AS1 serves as a competing endogenous (ceRNA) in RA-FLSs through the sponge of miR-1298-5p and increase in the expression of E2F1. Further restoration experiments revealed that miR-1298-5p mimics and E2F1 silencing could partially reverse the inhibiting effect of OSER1-AS1 overexpression on propagation and apoptosis in RA-FLSs. The results illustrated the biological mechanism of OSER1-AS1/miR-1298-59/E2F1 axis in RA progression. The outcomes indicated that OSER1-AS1 might be adopted as a hopeful diagnostic and therapeutic objective for RA.