Novel insights into exosomal circular RNAs: Redefining intercellular communication in cancer biology

Emerging Horizons in the Diagnosis of Pancreatic Cancer: The Role of Circulating microRNAs as Early Detection Biomarkers for Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer with a poor prognosis, primarily due to a late diagnosis. Recent studies have focused on identifying non-invasive biomarkers for early detection, with microRNAs (miRNAs) emerging as promising candidates. This systematic review aims to evaluate the potential of circulating miRNAs as biomarkers for the early detection of PDAC, analyzing their diagnostic accuracy, specificity, and sensitivity. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a comprehensive search across PubMed, Embase, and the Cochrane Library was conducted. Studies published from January 2013 to October 2023 focusing on miRNA biomarkers for early PDAC detection were included. Data synthesis was performed through a narrative approach due to the heterogeneity of the studies. Nine studies met the inclusion criteria. Key findings include the elevated levels of specific miRNAs, such as miR-18a, miR-106a, and miR-25, in early-stage PDAC patients compared to controls. The integration of miRNA profiles with traditional biomarkers like CA19-9 showed improved diagnostic performance. However, challenges in the standardization of miRNA evaluation methodologies were noted. Circulating miRNAs demonstrate significant potential as non-invasive biomarkers for early PDAC detection. Despite promising results, further research and standardization are necessary for clinical application.

Exosome-mediated transfer of circRNA563 promoting hepatocellular carcinoma by targeting the microRNA148a-3p/metal-regulatory transcription factor-1 pathway

BACKGROUND

Mesenchymal stem cells (MSCs) exert anti-oncogenic effects via exosomes containing non-coding RNA (ncRNA), which play important roles in tumor biology. Our preliminary study identified the interaction of the ncRNA hsa_circ_0000563 (circ563) and the circ563-associated miR-148a-3p in exosomes, as miR-148a-3p and its target metal-regulatory transcription factor-1 (MTF-1) are implicated in hepatocellular carcinoma (HCC) progression.

AIM

To identify the clinical significance, functional implications, and mechanisms of circ563 in HCC.

METHODS

The expression levels of miR-148a-3p and MTF-1 in exosomes derived from MSC and HCC cells were compared, and their effects on HCC cells were assessed. Using a dual-luciferase reporter assay, miR-148a-3p was identified as an associated microRNA of circ563, whose role in HCC regulation was assessed in vitro and in vivo.

RESULTS

The silencing of circ563 blocked the HCC cell proliferation and invasion and induced apoptosis. Co-culturing of HCC cells with MSC-derived exosomes following circ563 overexpression promoted cell proliferation and metastasis and elicited changes in miR-148a-3p and MTF-1 expression. The tumor-promoting effects of circ563 were partially suppressed by miR-148a-3p overexpression or MTF-1 depletion. Xenograft experiments performed in nude mice confirmed that circ563-enriched exosomes facilitated tumor growth by upregulating the expression of MTF-1. In HCC tissues, circ563 expression was negatively correlated with miR-148a-3p expression but positively correlated with MTF-1 levels.

CONCLUSION

MSCs may exhibit anti-HCC activity through the exosomal circ563/miR-148a-3p/MTF-1 pathway, while exosomes can transmit circ563 to promote oncogenic behavior by competitively binding to miR-148a-3p to activate MTF-1.

Molecular Biomarkers and Recent Liquid Biopsy Testing Progress: A Review of the Application of Biosensors for the Diagnosis of Gliomas

Gliomas are the most common primary central nervous system tumors, with a high mortality rate. Early and accurate diagnosis of gliomas is critical for successful treatment. Biosensors are significant in the detection of molecular biomarkers because they are simple to use, portable, and capable of real-time analysis. This review discusses several important molecular biomarkers as well as various biosensors designed for glioma diagnosis, such as electrochemical biosensors and optical biosensors. We present our perspectives on the existing challenges and hope that this review can promote the improvement of biosensors.

Exosomal circRNAs in cancer: Implications for therapy resistance and biomarkers

Despite the advances in cancer treatment in recent years, the development of resistance to cancer therapy remains the biggest hurdle towards curative cancer treatments. Therefore, investigating the molecular mechanisms underlying cancer therapy resistance is of paramount clinical importance. Circular RNAs (circRNAs), novel members of the noncoding RNA family, are endogenous biomolecules in eukaryotes characterized by a covalently closed loop structure with multiple biological functions. Significantly, circRNAs are abundant and stable in exosomes and can be packaged, secreted and transferred to targeted tumour cells, thereby modulating diverse hallmarks of cancer behaviours, such as proliferation, migration, and immune escape. Notably, a great number of exosomal circRNAs are abnormally expressed during cancer treatment and can mediate cancer therapy resistance through complex mechanisms; therefore, targeting exosomal circRNAs is a promising therapeutic method to reverse therapy resistance. This review aimed to elucidate the mechanisms underlying exosomal circRNAs controlling the resistance of cancer to common therapies, such as chemotherapy, targeted therapy, immunotherapy and radiotherapy, and we also discussed the therapeutic potential of exosomal circRNAs as clinical biomarkers and novel targets in cancer clinical management. We also discussed the prospects and challenges of targeting exosomal circRNAs as a novel therapeutic strategy for reversing cancer therapy resistance.

CircEGFR reduces the sensitivity of pirarubicin and regulates the malignant progression of triple-negative breast cancer via the miR-1299/EGFR axis

Circular RNAs (circRNAs) have been found to be involved in cancer progression and chemotherapy sensitivity. However, the biological function of circRNAs in triple-negative breast cancer (TNBC) and its effect on the sensitivity to pirarubicin (THP) chemotherapy are still unclear. CircEGFR (hsa_circ_0080220) was screened and verified by bioinformatics analysis, proving it was highly expressed in TNBC cell lines, patient tissues, and plasma exosomes, and was associated with poor prognosis of patients. The expression level of circEGFR in patient tissue has potential diagnostic value to distinguish TNBC tissue from normal breast tissue. In vitro studies confirmed that overexpression of circEGFR promoted the proliferation, migration, invasion, and EMT of TNBC cells and decreased the sensitivity of THP treatment while silencing circEGFR showed the opposite effect. The circEGFR/miR-1299/EGFR pathway was cascaded and verified. CircEGFR regulated malignant progression of TNBC by regulating EGFR via sponging miR-1299. THP can inhibit the malignant phenotype of MDA-MB-231 cells by downregulating the expression of circEGFR. In vivo studies confirmed that overexpression of circEGFR can promote tumor growth and EMT and reduce tumor sensitivity to THP treatment. Silencing circEGFR inhibited the malignant progression of the tumor. These results revealed circEGFR is a promising biomarker for TNBC diagnosis, therapeutic and prognosis.

CircSHOC2 Knockdown Alleviates High Glucose-Induced Vascular Endothelial Cell Pyroptosis via Targeting miR-145/FOXO1 Axis In Vitro Condition

Emerging evidence indicates that pyroptosis participates in the pathogenic process of vascular endothelial cells in cardiovascular system complications of diabetes. The roles of circular RNAs (circRNAs) in high glucose (HG)-induced vascular endothelial cells are still unclear. Here, our research investigated the function and mechanism of circRNA circSHOC2 in pyroptosis of vascular endothelial cells. Results indicated that circSHOC2 was up-regulated in HG-induced human umbilical vein endothelial cells (HUVECs). Functionally, cellular assays indicated that circSHOC2 silencing repressed HG-induced HUVECs pyroptosis. Moreover, circSHOC2 targeted miR-145 through miRNA sponge, and FOXO1 functioned as downstream target of miR-145. In conclusion, these findings suggested the potential roles of circSHOC2 on HG-induced vascular endothelial cells in vitro condition, providing new insights for cardiovascular system complications of diabetes.

Exosomes: A potential tool for immunotherapy of ovarian cancer

Ovarian cancer is a malignant tumor of the female reproductive system, with a very poor prognosis and high mortality rates. Chemotherapy and radiotherapy are the most common treatments for ovarian cancer, with unsatisfactory results. Exosomes are a subpopulation of extracellular vesicles, which have a diameter of approximately 30-100 nm and are secreted by many different types of cells in various body fluids. Exosomes are highly stable and are effective carriers of immunotherapeutic drugs. Recent studies have shown that exosomes are involved in various cellular responses in the tumor microenvironment, influencing the development and therapeutic efficacy of ovarian cancer, and exhibiting dual roles in inhibiting and promoting tumor development. Exosomes also contain a variety of genes related to ovarian cancer immunotherapy that could be potential biomarkers for ovarian cancer diagnosis and prognosis. Undoubtedly, exosomes have great therapeutic potential in the field of ovarian cancer immunotherapy. However, translation of this idea to the clinic has not occurred. Therefore, it is important to understand how exosomes could be used in ovarian cancer immunotherapy to regulate tumor progression. In this review, we summarize the biomarkers of exosomes in different body fluids related to immunotherapy in ovarian cancer and the potential mechanisms by which exosomes influence immunotherapeutic response. We also discuss the prospects for clinical application of exosome-based immunotherapy in ovarian cancer.

Unveiling the prominent roles of circular RNAs ubiquitin binding associated protein 2 in cancers

Circular RNAs (circRNAs), a novel type of covalently closed non-coding RNAs, are widely expressed in eukaryotes and viruses. Accumulating evidence has shown that circRNAs play key roles in the pathophysiological changes process of human diseases and can affect cancer development and progression through regulating target genes expression, linear RNA transcription and protein generation. Recent studies had found that circRNA-UBAP2 (ubiquitin binding associated protein 2) was aberrantly expressed in various human tumors and could affect tumor cells proliferation, migration, invasion, cell cycle, anti-apoptosis, radioresistance, chemoresistance and other malignant biological behavioral progress. Mechanistic studies further revealed that circUBAP2 could affect the occurrence and development of human tumors through multiple different molecular regulatory pathways in vivo and in vitro. In addition, the abnormal expression of circUBAP2 was significantly correlated with the clinicopathological characteristics of malignant tumors and had potential value as biomarkers for the diagnosis and prognosis evaluation of cancer patients, which deserved further study. This review had summarized and discussed the oncogenic roles and clinical performances of circUBAP2 in various human malignancies with a focus on biological functions and molecular mechanisms, which could help to elevate the understanding to the roles of circRNAs and continue subsequent studies on circUBAP2.

Potential value of differentially expressed circular RNAs derived from circulating exosomes in the pathogenesis of rat spinal cord injury

Spinal cord injury (SCI) remains one kind of devastating neurological damage, and specific molecular mechanisms involved need to be understood deeply. Currently, circular RNAs (circRNAs), as a newly discovered type of non-coding RNAs (ncRNAs), have been under active investigation. Through functional interactions with disease-associated microRNAs (miRNAs), exosome-derived circRNAs have been extensively implicated in various organ pathogenesis. Nevertheless, the functional involvement of circulating circRNAs in SCI onset, progression as well as repair remains poorly explored until now. Of note, there still lacks clinical and experimental evidence in this regard. To obtain some relevant knowledge in this field, this study was originally designed to have a general overview of differentially expressed circRNAs derived from circulating exosomes in SCI rats in comparison with the control rats. It turned out that 709 types of downregulated circRNAs and 346 kinds of upregulated circRNAs were preliminarily screened out. Functional enrichment analyses including kyoto encyclopedia of genes and genomes (KEGG) pathway and gene ontology (GO) were performed to evaluate the possible biological functions of upregulated as well as downregulated circRNAs involved in SCI. Furthermore, five types of upregulated circulating circRNAs including chr4:208359914–208362182+, chr15:20088296–20092102+, chr1:175098934– 175134845–, chr1:175099657– 175128203–, and chr1:175104454– 175134845–, and plus five kinds of downregulated circulating circRNAs including chr11:74154652– 74159524–, chr12:45412398– 45412635–, chr7:137630261– 137648924–, chr6:6280974–6281188+, and chr4:225251864–225254087+, were verified through reverse transcription-polymerase chain reaction (RT-PCR). At last, taking these differentially expressed circRNAs in the center, the circRNA-miRNA-mRNA gene interaction network was constructed to predict the possible functionalities of circRNAs in SCI through anticipating specific interactive miRNAs, giving new insights into how circRNAs contribute to this pathological process. Taken together, these findings suggest the possible involvement and functional significance of circRNAs in SCI.

Demystifying Extrachromosomal DNA Circles: Categories, Biogenesis, and Cancer Therapeutics

Since the advent of sequencing technologies in the 1990s, researchers have focused on the association between aberrations in chromosomal DNA and disease. However, not all forms of the DNA are linear and chromosomal. Extrachromosomal circular DNAs (eccDNAs) are double-stranded, closed-circled DNA constructs free from the chromosome that reside in the nuclei. Although widely overlooked, the eccDNAs have recently gained attention for their potential roles in physiological response, intratumoral heterogeneity and cancer therapeutics. In this review, we summarize the history, classifications, biogenesis, and highlight recent progresses on the emerging topic of eccDNAs and comment on their potential application as biomarkers in clinical settings.

CircRNAs: novel therapeutic targets in multiple myeloma

BACKGROUND

Circular RNA (circRNA) is a type of non-coding RNA that has recently attracted the attention of researchers. Multiple myeloma (MM) is a hematological malignancy with a dismal prognosis that indicates a pressing need for better treatment alternatives, particularly in terms of biological indicators. According to recent research findings, the presence of circRNA is also closely related to the incidence and progression of malignant hemopathy. There have been, however, only a few investigations of circRNA in MM.

MATERIAL AND METHODS

This review will be on the biological properties and functions of circRNA in MM and a discussion of the clinical utility of circRNA in the diagnosis, prognosis, and treatment of MM.

CONCLUSIONS

CircRNA is involved in gene transcription, translation, and epigenetic modification as well as the regulation of cancer cell proliferation, invasion, and metastasis, and hence, promotes or inhibits the occurrence and progression of MM. Therefore, circRNA holds promise as a potential future MM biomarker.