The circular RNA hsa_circ_0001394 promotes hepatocellular carcinoma progression by targeting the miR-527/UBE2A axis

CircWDR37 promotes hepatocellular carcinoma tumorigenesis by mediating the miR-646/TRAF4 regulatory pathway

BACKGROUND

CircRNA has emerged as a significant player in human malignancies, including hepatocellular carcinoma (HCC). Hsa_circ_0004277 (circWDR37) is abnormally up-regulated in HCC. But, its function and underlying mechanism in HCC progression are largely unknown.

METHODS

qRT-PCR and western blot assays were used to measure the expression of circWDR37, miR-646, and TRAF4. Cell malignant phenotypes were assessed via CCK-8, EdU, colony formation, flow cytometry, transwell, and tube formation experiments. The intermolecular interaction between miR-646 and circWDR37 or TRAF4 was confirmed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assay. The in vivo effect of circWDR37 on xenograft tumor growth was also investigated in mice.

RESULTS

Increased CircWDR37 and TRAF4 and decreased miR-646 were found in HCC tissues and cells. Scilencing circWDR37 impeded cell proliferation, migration, invasion, and tube formation, while accelerated apoptosis. CircWDR37 directly bind to miR-646 to suppress miR-646 expression and up-regulate TRAF4 expression. MiR-646 inhibitor partially abated the cell phenotype changes caused by circWDR37 knockdown. Moreover, miR-646 exerted an inhibitory effect on cell malignant phenotypes, which were attenuated due to the increase of TRAF4. Additionally, circWDR37 knockdown blocked HCC tumor growth in vivo.

CONCLUSION

CircWDR37 exerted an oncogenic effect in HCC by sponging miR-646 to up-regulate TRAF4 expression. Our finding elucidates a novel 'circWDR37-miR-646-TRAF4' regulatory axis in HCC and provides a promising target for HCC treatment.

Comprehensive analysis of circRNA expression profiles in postmenopausal women differing in bone mineral density

Postmenopausal osteoporosis (PMOP) seriously endangers the bone health of older women. Although there are currently indicators to diagnose PMOP, early diagnostic biomarkers are lacking. Circular ribonucleic acid (circRNA) has a stable structure, regulates gene expression, participates in the pathological process of disease, and has the potential to become a biomarker. The purpose of this study was to investigate circRNAs that could be used to predict patients with early PMOP. Ribonucleic acid (RNA) sequencing was performed on peripheral blood leukocytes from 15 female patients to identify differential circRNAs between different groups. Using bioinformatics analysis, enrichment analysis was performed to discover relevant functions and pathways. CircRNA-micro ribonucleic acid (miRNA) interaction analysis and messenger ribonucleic acid (mRNA) prediction and network construction help us to understand the relationship between circRNA, miRNA, and mRNA. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the gene expression of candidate circRNAs. We screened out 2 co-expressed differential circRNAs, namely hsa_circ_0060849 and hsa_circ_0001394. By analyzing the regulatory network, a total of 54 miRNAs and 57 osteoporosis-related mRNAs were identified, which, as potential downstream target genes of hsa_circ_0060849 and hsa_circ_0001394, may play a key role in the occurrence and development of PMOP. The occurrence and development of PMOP is regulated by circRNAs, and hsa_circ_0060849 and hsa_circ_0001394 can be used as new diagnostic markers and therapeutic targets for early PMOP.

Signatures of tumor-associated macrophages correlate with treatment response in ovarian cancer patients

Ovarian cancer (OC) ranks as the second leading cause of death among gynecological cancers. Numerous studies have indicated a correlation between the tumor microenvironment (TME) and the clinical response to treatment in OC patients. Tumor-associated macrophages (TAMs), a crucial component of the TME, exert influence on invasion, metastasis, and recurrence in OC patients. To delve deeper into the role of TAMs in OC, this study conducted an extensive analysis of single-cell data from OC patients. The aim is to develop a new risk score (RS) to characterize the response to treatment in OC patients to inform clinical treatment. We first identified TAM-associated genes (TAMGs) in OC patients and examined the protein and mRNA expression levels of TAMGs by Western blot and PCR experiments. Additionally, a scoring system for TAMGs was constructed, successfully categorizing patients into high and low RS subgroups. Remarkably, significant disparities were observed in immune cell infiltration and immunotherapy response between the high and low RS subgroups. The findings revealed that patients in the high RS group had a poorer prognosis but displayed greater sensitivity to immunotherapy. Another important finding was that patients in the high RS subgroup had a higher IC50 for chemotherapeutic agents. Furthermore, further experimental investigations led to the discovery that THEMIS2 could serve as a potential target in OC patients and is associated with EMT (epithelial-mesenchymal transition). Overall, the TAMGs-based scoring system holds promise for screening patients who would benefit from therapy and provides valuable information for the clinical treatment of OC.

Suppressing circIDE/miR-19b-3p/RBMS1 axis exhibits promoting-tumour activity through upregulating GPX4 to diminish ferroptosis in hepatocellular carcinoma

Ferroptosis is a newly characterized form of iron-dependent non-apoptotic cell death, which is closely associated with cancer progression. However, the functions and mechanisms in regulation of escaping from ferroptosis during hepatocellular carcinoma (HCC) progression remain unknown. In this study, we reported that the RNA binding motif single stranded interacting protein 1 (RBMS1) participated in HCC development，and functioned as a regulator of ferroptosis. Clinically, the downregulation of RBMS1 occurred in HCC tissues, and low RBMS1 expression was associated with worse HCC patients survival. Mechanistically, RBMS1 overexpression inhibited HCC cell growth by attenuating the expression of glutathione peroxidase 4 (GPX4)and further facilitated ferroptosis in vitro and in vivo. More importantly, a novel circIDE (hsa_circ_0000251) was identified to elevate RBMS1 expression via sponging miR-19b-3p in HCC cells. Collectively, our findings established circIDE/miR-19b-3p/RBMS1 axis as a regulator of ferroptosis, which could be a promising therapeutic target and prognostic factor.

Hepatocellular Carcinoma: Up-regulated Circular RNAs Which Mediate Efficacy in Preclinical In Vivo Models

Hepatocellular carcinoma (HCC) ranges as number two with respect to the incidence of tumors and is associated with a dismal prognosis. The therapeutic efficacy of approved multi-tyrosine kinase inhibitors and checkpoint inhibitors is modest. Therefore, the identification of new therapeutic targets and entities is of paramount importance. We searched the literature for up-regulated circular RNAs (circRNAs) which mediate efficacy in preclinical in vivo models of HCC. Our search resulted in 14 circRNAs which up-regulate plasma membrane transmembrane receptors, while 5 circRNAs induced secreted proteins. Two circRNAs facilitated replication of Hepatitis B or C viruses. Three circRNAs up-regulated high mobility group proteins. Six circRNAs regulated components of the ubiquitin system. Seven circRNAs induced GTPases of the family of ras-associated binding proteins (RABs). Three circRNAs induced redox-related proteins, eight of them up-regulated metabolic enzymes and nine circRNAs induced signaling-related proteins. The identified circRNAs up-regulate the corresponding targets by sponging microRNAs. Identified circRNAs and their targets have to be validated by standard criteria of preclinical drug development. Identified targets can potentially be inhibited by small molecules or antibody-based moieties and circRNAs can be inhibited by small-interfering RNAs (siRNAs) or short hairpin RNAs (shRNAs) for therapeutic purposes.

Nucleus-localized circSLC39A5 suppresses hepatocellular carcinoma development by binding to STAT1 to regulate TDG transcription

Accumulating evidence indicates that circular RNAs (circRNAs) are inextricably linked to cancer development. However, the function and mechanism of nucleus-localized circRNAs in hepatocellular carcinoma (HCC) still require investigation. Here, qRT-PCR and receiver-operating characteristic curve were used to detect the expression and diagnostic potential of circSLC39A5 for HCC. The biological function of circSLC39A5 in HCC was investigated in vitro and in vivo. Nucleoplasmic separation assay, fluorescence in situ hybridization, RNA pulldown, RNA immunoprecipitation, the HDOCK Server, the NucleicNet Webserver, crosslinking-immunoprecipitation, MG132 treatment, and chromatin immunoprecipitation were utilized to explore the potential molecular mechanism of circSLC39A5 in HCC. The results showed that circSLC39A5 was downregulated in both HCC tissues and plasma and was associated with satellite nodules and lymph node metastasis/vascular invasion. CircSLC39A5 was stably expressed in plasma samples under different storage conditions, showing good diagnostic potential for HCC (AUC = 0.915). CircSLC39A5 inhibited proliferation, migration, and invasion, facilitated the apoptosis of HCC cells, and was associated with low expression of Ki67 and CD34. Remarkably, circSLC39A5 is mainly localized in the nucleus and binds to the transcription factor signal transducer and activator of transcription 1 (STAT1), affecting its stabilization and expression. STAT1 binds to the promoter of thymine DNA glycosylase (TDG). Overexpression of circSLC39A5 elevates TDG expression and reverses the increase of proliferating cell nuclear antigen (PCNA) expression and the overactive cell proliferation caused by TDG silencing. Our findings uncovered a novel plasma circRNA, circSLC39A5, which may be a potential circulating diagnostic marker for HCC, and the mechanism by which nucleus-localized circSLC39A5 exerts a transcriptional regulatory role in HCC by affecting STAT1/TDG/PCNA provides new insights into the mechanism of circRNAs.

Upregulation of hsa_circ_0002003 promotes hepatocellular carcinoma progression

BACKGROUND

Circular RNAs (circRNAs), which are involved in various human malignancies, have emerged as promising biomarkers. The present study aimed to investigate unique expression profiles of circRNAs in hepatocellular carcinoma (HCC) and identify novel biomarkers associated with HCC development and progression.

METHODS

CircRNA expression profiles of HCC tissues were jointly analyzed to identify differentially expressed circRNAs. Overexpression plasmid and siRNA targeting candidate circRNAs were used in functional assays in vitro. CircRNA-miRNA interactions were predicted using miRNAs expressed in the miRNA-seq dataset GSE76903. To further screen downstream genes targeted by the miRNAs, survival analysis and qRT-PCR were conducted to evaluate their prognostic role in HCC and construct a ceRNA regulatory network.

RESULTS

Three significantly upregulated circRNAs, hsa_circ_0002003, hsa_circ_0002454, and hsa_circ_0001394, and one significantly downregulated circRNA, hsa_circ_0003239, were identified and validated by qRT-PCR. Our in vitro data indicated that upregulation of hsa_circ_0002003 accelerated cell growth and metastasis. Mechanistically, DTYMK, DAP3, and STMN1, which were targeted by hsa-miR-1343-3p, were significantly downregulated in HCC cells when hsa_circ_0002003 was silenced and were significantly correlated with poor prognosis in patients with HCC.

CONCLUSION

Hsa_circ_0002003 may play critical roles in HCC pathogenesis and serve as a potential prognostic biomarker for HCC. Targeting the hsa_circ_0002003/hsa-miR-1343-3p/STMN1 regulatory axis could be an effective therapeutic strategy in patients with HCC.

HtrA2 Independently Predicts Poor Prognosis and Correlates with Immune Cell Infiltration in Hepatocellular Carcinoma

High-temperature requirement protein A2 (HtrA2), a mitochondrial protein, is related to apoptosis regulation. However, the role of HtrA2 in hepatocellular carcinoma (HCC) remains unclear. In the present study, we explored the prognostic value and expression pattern of HtrA2 in HCC and confirmed its independent value for predicting outcomes via Cox analyses. LinkedOmics and GEPIA2 were used to construct the coexpression and functional networks of HtrA2. Additionally, the data obtained from TCGA was analyzed to investigate the relationship between the infiltration of immune cells and HtrA2 mRNA expression. Finally, the expression pattern of HtrA2 in HCC was confirmed by wet-lab experiments. The results showed high HtrA2 expression (P < 0.001) presented in tumor tissues in TCGA-HCC. Moreover, high HtrA2 expression was confirmed to be associated with poor HCC patient survival (P < 0.05). HtrA2 has also been recognized as an essential risk factor for overall survival (P=0.01, HR = 1.654, 95% CI 1.128-2.425), disease-specific survival (P=0.004, HR = 2.204, 95% CI 1.294-3.753), and progression-free interval (P=0.007, HR = 1.637, 95% CI 1.145-2.341) of HCC. HCC patients with low HtrA2 methylation had worse overall survival than patients with high methylation (P=0.0019). Functional network analysis suggests that HtrA2 regulates mitochondrial homeostasis through pathways involving multiple microRNAs and transcription factors in HCC. In addition, HtrA2 expression correlated with infiltrating levels of multiple immune cell populations. At last, increased expression of HtrA2 in HCC was confirmed using wet-lab experiments. Our study provides evidence that the upregulation of HtrA2 in HCC is an independent predictor of prognosis. Our results provide the foundation for further study on the roles of HtrA2 in HCC tumorigenesis.