Upregulation of circ_0008812 and circ_0001583 predicts poor prognosis and promotes breast cancer proliferation

Exosomal circ_0001583 Drives Glioblastoma Cell Advancement Through the miR-647/CKAP2L Pathway

Our study aimed to explore the involvement of circ_0001583 in the progression of glioblastoma (GBM). The expression levels of CircRNA in GBM were examined using the GEO database, and quantification of circ_0001583 levels was performed through qRT-PCR in both GBM tissues and cell lines. Survival analysis was conducted using Kaplan-Meier plots. The effects of circ_0001583 knockdown on cell proliferation, invasion, and glycolysis were evaluated through functional assays and measurements of glycolytic activity. Bioinformatics and reporter assays revealed that miR-647 serves as a target for circ_0001583. Tumorigenesis following circ_0001583 knockdown was investigated in a nude mouse model utilizing U251 cells. Additionally, a co-culture system with normal human astrocytes (NHAs) and GBM-conditioned medium was employed to study circ_0001583 expression and its influence on cell proliferation. The presence of circ_0001583 in normal human astrocytes was assessed using PKH67 labeling and immunofluorescence techniques. Bioinformatics analyses revealed a notable increase in the expression of circ_0001583 in GBM, correlating with metastasis. The inhibition of circ_0001583 expression led to decreased viability, proliferation, and invasive potential of GBM cells. It was found that circ_0001583 targets miR-647, which is downregulated in GBM. Silencing circ_0001583 resulted in elevated levels of miR-647. CKAP2L, a target of miR-647, showed an overexpression in GBM cases. Additionally, a positive relationship was established between circ_0001583 and CKAP2L, contrasting with a negative association with miR-647. An increase in miR-647 expression led to a decrease in CKAP2L protein levels. Rescue assays further validated that circ_0001583 influences the functions of GBM cells through the miR-647/CKAP2L pathway. In vivo investigations demonstrated that the knockdown of circ_0001583 resulted in retarded tumor growth, enhanced levels of miR-647, and diminished expression of Ki-67, CKAP2L, HK2, and LDHA within tumors. Moreover, co-culture studies involving GBM-conditioned medium demonstrated an upregulation of circ_0001583 in NHAs, which promoted cell proliferation. Our data collectively suggest that exosomal circ_0001583 promotes glioblastoma progression via the miR-647/CKAP2L pathway.

CircRNAs: Pivotal modulators of TGF-β signalling in cancer pathogenesis

The intricate molecular landscape of cancer pathogenesis continues to captivate researchers worldwide, with Circular RNAs (circRNAs) emerging as pivotal players in the dynamic regulation of biological functions. The study investigates the elusive link between circRNAs and the Transforming Growth Factor-β (TGF-β) signalling pathway, exploring their collective influence on cancer progression and metastasis. Our comprehensive investigation begins by profiling circRNA expression patterns in diverse cancer types, revealing a repertoire of circRNAs intricately linked to the TGF-β pathway. Through integrated bioinformatics analyses and functional experiments, we elucidate the specific circRNA-mRNA interactions that modulate TGF-β signalling, unveiling the regulatory controls governing this crucial pathway. Furthermore, we provide compelling evidence of the impact of circRNA-mediated TGF-β modulation on key cellular processes, including epithelial-mesenchymal transition (EMT), migration, and cell proliferation. In addition to their mechanistic roles, circRNAs have shown promise as diagnostic and prognostic biomarkers, as well as potential molecular targets for cancer therapy. Their ability to modulate critical pathways, such as the TGF-β signalling axis, underscores their significance in cancer biology and clinical applications. The intricate interplay between circRNAs and TGF-β is dissected, uncovering novel regulatory circuits that contribute to the complexity of cancer biology. This review unravels a previously unexplored dimension of carcinogenesis, emphasizing the crucial role of circRNAs in shaping the TGF-β signalling landscape.

Identification of circRNA-miRNA-mRNA network in luminal breast cancers by integrated analysis of microarray datasets

Introduction: Circular RNAs (circRNAs) regulatory network is important in human cancer. We, therefore, mapped the regulatory networks driven by circRNA in luminal-subtype breast cancer. Methods: Breast cancer-related microarray datasets from GEO database were analyzed for the differentially expressed circRNAs, miRNAs, and mRNAs. The potential downstream RNAs were collected using Circular RNA Interactome or Targetscan database. Protein-protein interaction (PPI) analysis was performed for the filtered genes to identify hub genes. The functions were annotated by the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. CircRNA-miRNA-mRNA networks were mapped using Cytoscape software. Hsa_circ_0086735-miR-1296-5p-STAT1 axis was used for verification. The expression levels of hsa_circ_0086735, miR-1296-5p, and STAT1 mRNA were confirmed by qRT-PCR in luminal-subtype tissues and cell lines. The interactions among them were verified by Luciferase reporter assay and RNA pull-down assay. Cell proliferation and apoptosis were assayed. Overall and distant metastasis-free survival was analyzed. Results: A total of 70 genes were finally targeted and enriched in multi-process and multi-pathway. Networks containing 96 circRNA-miRNA-mRNA axes were constructed. Hsa_circ_0086735 and STAT1 mRNA was upregulated in luminal breast cancer, while miR-1296-5p was downregulated. Hsa_circ_0086735-miR-1296-5p-STAT1 axis promotes breast cancer progression and contributes to tamoxifen resistance. High hsa_circ_0086735 was associated with poor overall and distant metastasis-free survival. Discussion: This study identified the hsa_circ_0086735-miR-1296-5p-STAT1 as an important regulatory axis in luminal-subtype breast cancer, aiding to determine potential therapeutic targets.