CircZFR promotes colorectal cancer progression via stabilizing BCLAF1 and regulating the miR-3127-5p/RTKN2 axis.

Aberrant expression of circular RNAs (circRNAs) is frequently linked to colorectal cancer (CRC). Here, we identified circZFR as a promising biomarker for CRC diagnosis and prognosis. CircZFR was upregulated in CRC tissues and serum exosomes and its level was linked to cancer incidence, advanced-stages, and metastasis. In both in vitro and in vivo settings, circZFR promoted the growth and spread while suppressing apoptosis of CRC. Exosomes with circZFR overexpression promoted the proliferation and migration of cocultured CRC cells. Mechanistically, epithelial splicing regulatory protein 1 (ESRP1) in CRC cells may enhance the production of circZFR. BCL2-associated transcription factor 1 (BCLAF1) bound to circZFR, which prevented its ubiquitinated degradation. Additionally, circZFR sponged miR-3127-5p to boost rhotekin 2 (RTKN2) expression. Our TCP1-CD-QDs nanocarrier was able to carry and deliver circZFR siRNA (si-circZFR) to the vasculature of CRC tissues and cells, which inhibited the growth of tumors in patient-derived xenograft (PDX) models. Taken together, our results show that circZFR is an oncogenic circRNA, which promotes the development and spread of CRC in a BCLAF1 and miR-3127-5p-dependent manner. CircZFR is a possible serum biopsy marker for the diagnosis and a desirable target for further treatment of CRC.

Circulating RNA ZFR promotes hepatocellular carcinoma cell proliferation and epithelial-mesenchymal transition process through miR-624-3p/WEE1 axis.

BACKGROUND: Hepatocellular carcinoma (HCC), the most common type of primary liver cancer, is the fourth leading cause of cancer-related deaths worldwide. Previous evidence shows that the expression of circulating RNA ZFR (circZFR) is upregulated in HCC tissues. However, the molecular mechanism of circZFR in HCC is unclear. METHODS: Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was employed to detect the expression of circZFR, microRNA-624-3p (miR-624-3p) and WEE1 in HCC tissues and cells. RNase R assay and actinomycin D treatment assay were used to analyze the characteristics of circZFR. For functional analysis, the capacities of colony formation, cell proliferation, cell apoptosis, migration and invasion were assessed by colony formation assay, 5-ethynyl-2'-deoxyuridine (EdU) assay, flow cytometry assay and transwell assay. Western blot was used to examine the protein levels of WEE1 and epithelial-mesenchymal transition (EMT)-related proteins. The interactions between miR-624-3p and circZFR or WEE1 were validated by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Xenograft models were established to determine the role of circZFR in vivo. RESULTS: circZFR and WEE1 were upregulated, while miR-624-3p expression was reduced in HCC tissues and cells. circZFR could sponge miR-624-3p, and WEE1 was a downstream gene of miR-624-3p. Knockdown of circZFR significantly reduced the malignant behaviors of HCC and that co-transfection with miR-624-3p inhibitor restored this change. Overexpression of WEE1 abolished the inhibitory effect of miR-624-3p mimic on HCC cells. Mechanistically, circZFR acted as a competitive endogenous RNA (ceRNA) to regulate WEE1 expression by targeting miR-624-3p. Furthermore, in vivo studies have illustrated that circZFR knockdown inhibited tumor growth. CONCLUSIONS: circZFR knockdown reduced HCC cell proliferation, migration and invasion and promoted apoptosis by regulating the miR-624-3p/WEE1 axis, suggesting that the circZFR/miR-624-3p/WEE1 axis might be a potential target for HCC treatment.

CircZFR promotes pancreatic cancer progression through a novel circRNA-miRNA-mRNA pathway and stabilizing epithelial-mesenchymal transition protein.

Pancreatic cancer (PC) ranks third in incidence and seventh in mortality among cancers worldwide. CircZFR has been implicated in various human cancers. Yet, how they affect PC progression is understudied. Herein, we demonstrated that circZFR was upregulated in PC tissues and cells, a feature that was correlated with the poor performance of patients with PC. Functional analyses elucidated that circZFR facilitated cell proliferation and enhanced tumorigenicity of PC. Moreover, we found that circZFR facilitated cell metastasis by differentially regulating the levels of proteins related to epithelial-mesenchymal transition (EMT). Mechanistic investigations revealed that circZFR sponged miR-375, thereby upregulating the downstream target gene, GREMLIN2 (GREM2). Additionally, circZFR knockdown resulted in attenuation of the JNK pathway, an effect that was reversed by GREM2 overexpression. Collectively, our findings implicate circZFR as a positive regulator of PC progression through the miR-375/GREM2/JNK axis.

Circular RNA ZFR promotes cell cycle arrest and apoptosis of colorectal cancer cells via the miR-147a/CACUL1 axis.

Background: Colorectal cancer (CC) is one of the most prevalent malignancies worldwide. Nonetheless, its pathogenicity and molecular mechanisms have not been completely elucidated yet. The potential clinical value of circular RNAs (circRNAs) in tumor diagnosis, treatment, and prognosis has received considerable attention. Methods: Here, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) examined the levels of circular ZFR (circZFR) in CC cells. The expression of circZFR was knocked down in CC cells and cell viability was detected using Cell Counting Kit-8 (CCK-8) and colony formation assays. Cell cycle progression was assessed by flow cytometry and the expression levels of cyclin-associated proteins were detected by western blot analysis. The transferase dUTP nick end labeling (TUNEL) assay was used to detect apoptosis and western blot analysis was used to evaluate the expression levels of apoptosis-associated proteins. Subsequently, the interactions between circZFR and microRNA (miR)-147a and between miR-147a and CDK2 associated cullin domain 1 (CACUL1) were predicted by the Encyclopedia of RNA Interactomes database and verified by luciferase reporter assays. Finally, plasmid transfection, CCK-8, and flow cytometry assays were used to explore the associated mechanism of action. Results: CircZFR was highly expressed in CC cell lines. Interference with its expression inhibited proliferation and induced G1/S cell cycle arrest and apoptosis in CC cells. The expression levels of miR-147a and CACUL1 were decreased and increased, respectively, in CC cells. These data demonstrated that circZFR could target miR-147a and CACUL1 to regulate the cell cycle and apoptosis of CC cells and, ultimately, promote the progression of CC. Conclusions: Knockdown of the expression of circZFR upregulated miR-147a expression and reduced CACUL1 expression levels, thereby inhibiting the proliferation of CC cells and inducing cell cycle arrest and apoptosis.

Prognostic and clinicopathologic significance of circZFR in multiple human cancers.

BACKGROUND: Abnormally expressed in diverse cancers, circZFR has been correlated with clinical outcomes of cancer patients. Aim of this meta-analysis was to elucidate the prognostic role of circZFR in multiple human malignancies. METHODS: Literature retrieval was conducted by systematically searching on Pubmed, Web of Science, and the Cochrane Library up to December 2nd, 2021. Hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were pooled to evaluate the association between circZFR expression and overall survival (OS). The reliability of the pooled results was assessed through sensitivity analysis and the publication bias was measured by Begg's and Egger's test. RESULTS: A total of seventeen studies comprising 1098 Chinese patients were enrolled in this meta-analysis. Results demonstrated that high circZFR expression was correlated with an unfavorable OS (HR = 2.14, 95% CI 1.74, 2.64). High circZFR expression predicted larger tumor size (OR = 2.79, 95% CI 1.52, 5.12), advanced clinical stage (OR = 3.38, 95% CI 1.49, 7.65), tendentiousness of lymph node metastasis (LNM) (OR = 3.08, 95% CI 2.01, 4.71), and malignant grade (OR = 3.18, 95% CI 1.09, 9.30), but not related to age, gender, and distant metastasis (DM). CONCLUSIONS: High circZFR expression was associated with unfavorable OS and clinicopathologic parameters including tumor size, clinical stage, LNM, and histology grade, implicating a promising prognostic factor in cancers.

Circ_ZFR affects FABP7 expression to regulate breast cancer progression by acting as a sponge for miR-223-3p.

BACKGROUND: Breast cancer (BC) is a common malignancy in women. Circular RNAs (circRNAs) have been reported to play a key role in the development of BC; however, the effect of circular RNA zinc finger RNA binding protein (circ_ZFR) in BC is unknown. METHODS: Abundances of circ_ZFR, fatty acid binding protein 7 (FABP7), and microRNA-223-3p (miR-223-3p) were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The circular structure of circ_ZFR was validated by RNase R treatment. Cell proliferation, migration, invasion, and apoptosis were assessed by colony formation, cell counting kit-8, Transwell, flow cytometry assays, respectively. All protein levels were determined by Western blot. Dual-luciferase reporter assay was used to confirm the relationship between miR-223-3p and circ_ZFR or FABP7. A xenograft model was established to understand the effect of circ_ZFR on BC cell growth in vivo. RESULTS: The expression levels of circ_ZFR and FABP7 were higher in BC tissues and cell lines, whereas miR-223-3p expression was lower. Knockdown of circ_ZFR or FABP7 in BC cells reduced proliferation, migration, invasion, and epithelial mesenchymal transition (EMT), and induced apoptosis in vitro, whereas the opposite effects were observed in circ_ZFR-overexpressed cells. Furthermore, circ_ZFR might act as a sponge for miR-223-3p to regulate FABP7 expression, thereby promoting the progression of BC cells in vitro and in vivo. CONCLUSION: Circ_ZFR might act as a miRNA sponge for miR-223-3p to regulate FABP7, thereby promoting proliferation, migration, invasion, and EMT of BC cells, and inhibiting cell apoptosis.

Cancer-associated fibroblast exosomes promote chemoresistance to cisplatin in hepatocellular carcinoma through circZFR targeting signal transducers and activators of transcription (STAT3)/ nuclear factor -kappa B (NF-κB) pathway.

Chemoresistance in hepatocellular carcinoma (HCC) has been found to be influenced by exosomal transport of circRNAs. However, the role of circZFR in HCC chemoresistance still remains unclear. In the present study, circZFR was highly expressed in cisplatin (DDP)-resistant HCC cell lines and could regulate DDP resistance of the HCC cells. Also, circZFR was highly expressed in cancer-associated fibroblast (CAFs) and the exosome of CAFs. In addition, supplementation of CAFs in culture medium could promote DDP resistance of HCC cells. In vivo tumor xenograft experiments showed that knockdown of circZFR inhibited tumor growth and weakened DDP resistance, while CAFs-derived exosomes incubation increased the expression of circZFR, inhibited the STAT3/NF-κB pathway, promoted tumor growth, and enhanced DDP resistance. In general, CAFs-derived exosomes deliver circZFR to HCC cells, inhibit the STAT3/NF-κB pathway, and promote HCC development and chemoresistance. The results provided a new sight for the prevention and treatment of chemoresistance in HCC.

circZFR regulates thyroid cancer progression by the miR-16/MAPK1 axis.

Previous studies have identified the dysregulation of various circRNAs in many types of human cancers including thyroid cancer (TC). Circular RNA ZFR (circZFR) serves as an oncogenic circRNA in TC. However, the detailed molecular mechanism of circZFR in TC progression remains to be further explored. CircZFR and miR-16 expressions in TC cells were analyzed through qRT-PCR. Cell viability, invasion, and apoptosis were detected using CCK-8, transwell invasion assay, and flow cytometry analysis, respectively. The relationship between circZFR and miR-16 was explored using luciferase reporter assay, RNA pull-down assay, and qRT-PCR. The relationship between miR-16 and mitogen-activated protein kinase 1 (MAPK1) was explored using luciferase reporter assay and western blot analysis. Results showed that circZFR was upregulated and miR-16 was downregulated in TC cells. CircZFR knockdown inhibited the viability and invasion and induced apoptosis in TC cells. CircZFR inhibited miR-16 expression by sponging miR-16 and miR-16 repressed MAPK1 expression by targeting MAPK1. Moreover, circZFR positively regulated MAPK1 expression in TC cells by serving as a ceRNA of miR-16. Mechanistically, circZFR knockdown-induced inhibition of cell viability and invasion and promotion of apoptosis were overturned after miR-16 downregulation and promotion of MAPK1. Collectively, circZFR knockdown retarded TC progression by sponging miR-16 and modulating MAPK1 expression.

Circular RNA circZFR Promotes Hepatocellular Carcinoma Progression by Regulating miR-375/HMGA2 Axis.

BACKGROUND: Mounting evidence indicates that circular RNAs (circRNAs) have vital roles in human diseases, especially in cancers. AIMS: The aim of this study was to explore the biological functions and underlying mechanism of circRNA zinc finger RNA binding (circZFR) in hepatocellular carcinoma (HCC). METHODS: The expression levels of circZFR, microRNA-375 (miR-375) and high mobility group A2 (HMGA2) were detected by qRT-PCR or western blot assay. Glycolytic metabolism was examined via the measurement of extracellular acidification rate, oxygen consumption rate, glucose uptake, lactate production, and ATP level. MTT assay and flow cytometry were used to assess cell proliferation and cell apoptosis, respectively. The interaction between miR-375 and circZFR or HMGA2 was verified by dual-luciferase reporter and RNA Immunoprecipitation (RIP) assays. The mice xenograft model was established to investigate the role of circZFR in vivo. RESULTS: CircZFR and HMGA2 were upregulated while miR-375 was downregulated in HCC tissues and cells. CircZFR silence inhibited HCC progression by inhibiting cell proliferation, glycolysis and tumor growth and promoting apoptosis. MiR-375 was a direct target of circZFR and its knockdown reversed the inhibitory effect of circZFR silence on the progression of HCC cells. Moreover, HMGA2 was a downstream target of miR-375, and miR-375 suppressed proliferation and glycolysis and induced apoptosis by targeting HMGA2 in HCC cells. Besides, circZFR acted as a molecular sponge of miR-375 to regulate HMGA2 expression. CONCLUSION: Knockdown of circZFR suppressed the progression of HCC by upregulating miR-375 and downregulating HMGA2, providing new insight into the pathogenesis of HCC.

Circ_ZFR contributes to the paclitaxel resistance and progression of non-small cell lung cancer by upregulating KPNA4 through sponging miR-195-5p.

BACKGROUND: A growing body of evidence has demonstrated the vital roles of circular RNAs (circRNAs) in cancer progression and drug resistance. We intended to explore the roles and mechanisms of circ_ZFR in the paclitaxel (PTX) resistance and progression of non-small cell lung cancer (NSCLC). METHODS: Two NSCLC cell lines A549 and H460 were used in this study. Quantitative real-time polymerase chain reaction (qRT-PCR) assay was conducted to measure the levels of circ_ZFR, ZFR, miR-195-5p and karyopherin subunit alpha 4 (KPNA4) mRNA. RNase R assay was used to analyze the characteristic of circ_ZFR. MTT assay was carried out to assess PTX resistance and cell proliferation. Flow cytometry analysis was utilized to analyze cell cycle and apoptosis. Transwell assay was used to examine cell migration and invasion. Western blot assay was conducted to measure the protein levels of Ki67, Twist1, E-cadherin and KPNA4. Dual-luciferase reporter assay was adopted to verify the combination between miR-195-5p and circ_ZFR or KPNA4. Murine xenograft model assay was used to investigate the effect of circ_ZFR on PTX resistance of NSCLC in vivo. RESULTS: Circ_ZFR level was enhanced in PTX-resistant NSCLC tissues and cells. Knockdown of circ_ZFR suppressed PTX resistance, cell cycle process, proliferation, migration and invasion and induced apoptosis in PTX-resistant NSCLC cells. For mechanism analysis, circ_ZFR knockdown markedly downregulated the expression of KPNA4 by sponging miR-195-5p, thereby promoting PTX sensitivity and suppressing cell progression in PTX-resistant NSCLC cells. In addition, circ_ZFR silencing enhanced PTX sensitivity of NSCLC in vivo. CONCLUSION: Circ_ZFR knockdown played a positive role in overcoming PTX resistance of NSCLC via regulating miR-195-5p/KPNA4 axis, which might provide a possible circRNA-targeted therapy for NSCLC.

CircZFR functions as a sponge of miR-578 to promote breast cancer progression by regulating HIF1A expression.

BACKGROUND: Breast cancer (BC) is the most common malignancy among women. Emerging studies have demonstrated that circular RNA (circRNA) zinc finger RNA binding protein (circZFR) serves as a crucial regulator in many human cancers. However, the role and mechanism of circZFR in BC tumorigenesis remain unclear. METHODS: The levels of circZFR, miR-578 and hypoxia-inducible factor 1α (HIF1A) were detected by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Cell viability, colony formation, apoptosis, migration and invasion capacities in vitro were determined by using the Cell Counting Kit-8 (CCK-8), standard colony formation, flow cytometry and transwell assays, respectively. Glucose uptake, lactate product and adenosine triphosphate (ATP) levels of cells in vitro were measured using the commercial human assay kits. Targeted relationships among circZFR, miR-578 and HIF1A in BC cell lines were verified by dual-luciferase reporter and RNA pulldown assays. Animal studies were performed to assess the effect of circZFR on tumor growth in vivo. RESULTS: Our data indicated that circZFR was overexpressed in BC tissues and cells, and the increased circZFR level predicted poor prognosis of BC patients. CircZFR silencing or miR-578 overexpression repressed BC cell viability, colony formation, migration, invasion, and glycolysis and enhanced cell apoptosis in vitro. CircZFR silencing also hampered tumor growth in vivo. Mechanistically, circZFR acted as a sponge of miR-578, and circZFR silencing hindered BC cell malignant behaviors by miR-578. HIF1A was a functional target of miR-578 in regulating BC cell viability, colony formation, migration, invasion, glycolysis and apoptosis in vitro. Furthermore, circZFR modulated HIF1A expression through sponging miR-578. CONCLUSION: Our findings first identified that the silencing of circZFR suppressed BC malignant progression in vitro via the regulation of the miR-578/HIF1A axis, providing evidence for the crucial involvement of circZFR in BC pathogenesis.

Circ-ZFR Promotes Progression of Bladder Cancer by Upregulating WNT5A Via Sponging miR-545 and miR-1270.

BACKGROUND: Bladder cancer is one of the most common cancers all over the world. CircZFR is a circular RNA and has been implicated in tumor generation and invasion. However, the exact role of circZFR in the development of bladder cancer (BCa) remains unknown. This study aimed to investigate the function of circZFR in BCa, and further to probe into the association between circ-ZFR, miR-545/miR-1270 and WNT5A. METHODS: The expression of circZFR in BCa was quantified by qRT-PCR and was positively correlated with the prognosis of BCa patients. Next, the stable knockdown of circZFR BCa cell lines was established and the resulting capacities of proliferation, migration and invasion were measured. The association of circZFR with miR-1270/miR-545 was predicted by circinteractome prediction, and was confirmed by luciferase assay as well as RNA pull down assay. Furthermore, miRNA inhibitors, WNT5A overexpression and Pearson correlation analysis were used to examine the relationship between circZFR, miR-1270/miR-545 and WNT5A. RESULTS: The expression of CircZFR was up-regulated both in BCa tissues and in BCa cell lines, and was positively correlated with patient survival rates. Blocking of circZFR's expression by RNA inhibitors suppressed the proliferation, migration and invasion of BCa cells both in vitro and in vivo. On the other hand, overexpression of target miRNA supported that circZFR directly interact with miR-545 and miR-1270. Moreover, we demonstrated that circZFR promotes the progression of BCa by upregulating WNT5A's expression via sponging miR-545 and miR-1270. CONCLUSIONS: CircZFR promotes the proliferation, migration and invasion of BCa cells by upregulating WNT5A signaling pathway via sponging miR-545 and miR-1270. These results provide new insights into the molecular mechanism of circZFR in BCa progression, and more important, a novel target for BCa clinical treatment.

Circular RNA circZFR promotes tumorigenic capacity of lung cancer via CCND1.

BACKGROUND: To explore the role of circular RNA (circRNA) circZFR in tumorigenic capacity of lung cancer (LC). METHODS: Thirty primary LC tissues were used to detect circRNAs expression. CircZFR was silenced in two LC cell lines using lentivirus-mediated short hairpins RNAs. Quantitative real time PCR (qRT-PCR), northern blot and in situ hybridization (ISH) assay were used to measure the expression of circRNA. RESULTS: CircRNA circZFR was highly expressed in LC tumors. CircZFR deficiency significantly abrogated clone formation. CircZFR depletion substantially decreased tumor growth compared to WT control cells. CircZFR overexpression was dramatically increased cell growth in LC cell lines. Consequently, circZFR overexpression substantially promoted tumor propagation. Consistently, circZFR deficiency significantly reduced the expression of CCND1 and major cell cycle genes in LC cell lines. In contrast, circZFR depletion did not alter the expression of ZFR. Consequently, circZFR deficiency dramatically decreased H3K4me3 levels on the CCND1 promoter at -1,100 to -900 bp segment of CCND1 promoter. CONCLUSIONS: CircZFR was related with LC growth in vitro and in vivo and tumorigenic capacity of LC. The possible mechanism was to regulating expression of CCND1, indicating the circZFR/CCND1 signaling might be a promising therapeutic target for LC treatment.

CircZFR serves as a prognostic marker to promote bladder cancer progression by regulating miR-377/ZEB2 signaling.

Circular RNAs (circRNAs) have been identified as crucial regulators of gene expression in human cancer biology. CircZFR is a novel identified circRNA and its effect in bladder cancer remains unclearly. In the present study, we aimed to investigate the role of circZFR in the progression of bladder cancer. First, we demonstrated that the expression of circZFR was higher in bladder cancer tissues and cells compared with adjacent non-tumor tissues and normal bladder epithelial cells. And higher circZFR levels were positively correlated with bladder cancer patients' pathological T stage, grade, lymphatic metastasis, recurrence, progression-free survival (PFS) and overall survival (OS). Functionally, knockdown of circZFR could significantly prohibit cell growth, migration and invasion, arrest cell cycle as well as promote apoptosis of bladder cancer cells in vitro study. Mechanistically, we observed that circZFR could directly bind to miR-377 as sponge to promote ZEB2 expression in bladder cancer cells. In addition, rescue assays demonstrated that restoration of ZEB2 significantly impaired the suppressive effects of circZFR silencing on bladder cancer cells growth, migration and invasion. Taken together, our results illuminated that circZFR could be a prognostic biomarker in bladder cancer and exerted oncogenic roles through regulating miR-377/ZEB2 axis in bladder cancer, which indicated that circZFR could be a potential therapeutic target for bladder cancer patients treatment.

Silencing circZFR inhibits the proliferation, migration and invasion of human renal carcinoma cells by regulating miR-206.

BACKGROUND: Renal cell carcinoma (RCC) is the most prevalent kind of kidney cancer. At present, the most efficient treatment mean is surgery. 40% patients with clear cell RCC (ccRCC) relapse after surgery. Identifying novel therapeutic markers and spots for early detection and treatment of RCC is necessary. METHODS: qRT-PCR was utilized to quantify circZFR and miR-206 expression in CAKI-1 and ACHN cells. Cell viability was detected by CCK-8 assay. Colony formation capacity was measured by colony formation assay. Transwell assay was utilized to investigate migration and invasion capacity. Expression of migration and apoptosis-associated proteins was quantified by Western blot. RESULTS: As a result, circZFR was highly expressed in RCC tissues and cells. Si-circZFR suppressed cell growth, migration and invasion of experimental cells. In addition, knockdown of circZFR upregulated miR-206 expression. Moreover, the antigrowth, antimigrating and anti-invasive effects of si-circZFR were attenuated when downregulating miR-206. Furthermore, Met is the target gene of miR-206 in experimental cells. The suppression on these signaling pathways was acted by targeting miR-206/Met axis. CONCLUSION: The results demonstrated si-circZFR inhibited cell growth, migration and invasion in experimental cells by up-regulating of miR-206. Furthermore, si-circZFR suppressed Wnt/ß-catenin and PI3K/AKT pathways via targeting miR-206/Met axis.

Circular RNA ZFR accelerates non-small cell lung cancer progression by acting as a miR-101-3p sponge to enhance CUL4B expression.

BACKGROUND: Non-small-cell lung carcinoma (NSCLC) is the most common type of lung cancer. Circular RNA ZFR (circZFR) is an identified circular RNA (circRNA) that is correlated with cancer progression. However, the role of circZFR in NSCLC remains unknown. In the present study, we aimed to investigate the function of circZFR in NSCLC and the underlying mechanism. METHODS: The expression patterns of circZFR were determined using qRT-PCR in NSCLC samples and cell lines. The subcellular distribution of circZFR in NSCLC cells was analyzed by fluorescence in situ hybridization (FISH). Cell proliferation was examined utilizing the CCK-8 assay. Cell migration and invasion were evaluated using the Transwell assay. We used the bioinformatics software TargetScan and miRanda to predict circRNA-miRNA and miRNA-mRNA interactions. RESULTS: Our results showed that circZFR expressions were significantly upregulated in NSCLC tissues and cell lines. Knockdown of circZFR significantly inhibited the cell proliferation, migration and invasion of NSCLC cells in vitro. Furthermore, we demonstrated that circZFR acted as a sponge to absorb microRNA-101-3p (miR-101-3p) and promoted cullin 4B (CUL4B) expression. CONCLUSIONS: Collectively, our results demonstrated that circZFR exhibited a carcinogenic role by sponging miR-101-3p and regulating CUL4B expression in NSCLC. These findings provided evidence for understanding the role of circZFR in NSCLC tumourigenesis.

circZFR promotes cell proliferation and migration by regulating miR-511/AKT1 axis in hepatocellular carcinoma.

BACKGROUND: Emerging data suggest the crucial regulatory roles of circular RNAs (circRNAs) in hepatocellular carcinoma (HCC). However, the pathophysiology role of circZFR in HCC remains largely unknown. AIMS: This study aims to disclose the functions of circZFR in HCC progression and its potential molecular mechanism. METHODS: circZFR and miR-511 were identified by qRT-PCR. Colony formation assay, wound-healing assay, transwell assay, and flow cytometry assay were performed to determine the cell proliferation, migration, invasion and apoptosis. Western blotting and immunohistochemistry (IHC) were utilized to evaluate the expression level of AKT1, GSK3ß, ß-catenin and cascades of proliferation-related proteins both in vitro and in vivo. Dual luciferase reporter assay was conducted to evaluate the interactions among circZFR, miR-511 and AKT1. RESULTS: The expression of circZFR was enhanced and the expression of miR-511 was down-regulated in HCC tissues and cells. Functionally, circZFR silencing or miR-511 overexpression suppressed cell proliferation, migration and invasion, and induced apoptosis of HCC cells. Mechanistically, circZFR acted as a miR-511 sponge to up-regulate its target gene AKT1, which activated cascades of proliferation-related proteins (c-Myc, cyclin D1, Survivin and Bcl-2). Furthermore, depletion of circZFR inhibited tumorigenesis and decreased the expression level of AKT1 in xenograft models. CONCLUSION: circZFR promotes HCC progression by directly down-regulating miR-511 to activate AKT1 signaling, suggesting that circZFR is a potential target in HCC treatment. Targeting circZFR may provide therapeutic benefits for HCC.

CircZFR promotes hepatocellular carcinoma progression through regulating miR-3619-5p/CTNNB1 axis and activating Wnt/ß-catenin pathway.

Circular RNAs (circRNAs) have been discovered to exert essential roles in human cancers, including hepatocellular carcinoma. Although circZFR has been reported to facilitate the growth of papillary thyroid cancer, the role of circZFR in hepatocellular carcinoma (HCC) are largely unknown. In this study, bioinformatics analysis showed that circZFR was closely related with hepatocellular carcinoma. We then detect the expression of circZFR in HCC tissues using qRT-PCR. Furthermore, Kaplan-Meier method and log rank test revealed that high expression of circZFR was associated with the poor prognosis of patients with HCC. Subsequently, loss-of-function assay indicated that circZFR knockdown significantly suppressed cell proliferation and epithelial-mesenchymal transition (EMT) in HCC. In addition, microarray analysis was utilized to identify the differentially expressed mRNAs in response to circZFR knockdown. Moreover, Gene Ontology (GO) analysis further showed that circZFR might regulate Wnt/ß-catenin signaling pathway. The results were further confirmed by luciferase reporter assay and western blot assays. Then bioinformatics tools predicted that cicrZFR enhanced the CTNNB1 expression via sponging miR-3619-5p. In summary, our findings indicated that circZFR may exert carcinogenic role in HCC through regulating miR-3619-5p/CTNNB1 axis and activating Wnt/ß-catenin pathway. These findings may provide a novel perspective for the treatment of hepatocellular carcinoma.

Circular RNA circZFR contributes to papillary thyroid cancer cell proliferation and invasion by sponging miR-1261 and facilitating C8orf4 expression.

In recent years, more and more circular RNAs (circRNAs) have been identified in multiple tissues and cells. Increasing evidences show circRNAs play important roles in human cancers. However, the role of circRNAs in papillary thyroid carcinoma (PTC) remains largely unknown. In this study, we identified a new circRNA circZFR that was significantly upregulated in PTC tissues compared to adjacent normal tissues. Furthermore, circZFR expression level was negatively correlated with clinical severity. We found that circZFR knockdown dramatically inhibited the proliferation, migration and invasion of PTC cells in vitro. Mechanistically, we found circZFR could promote C8orf4 expression via serving as a competing endogenous RNA (ceRNA) of miR-1261 in PTC cells. Rescue assays indicated that restoration of C8orf4 significantly attenuated the inhibitory effects of circZFR knockdown on PTC cell proliferation, migration and invasion. In summary, our findings demonstrated that circRNA circZFR exerted oncogenic roles via regulating miR-1261/C8orf4 axis in PTC, which suggested circZFR might be a potential therapeutic target.

Circular RNA-ZFR Inhibited Cell Proliferation and Promoted Apoptosis in Gastric Cancer by Sponging miR-130a/miR-107 and Modulating PTEN.

PURPOSE: This study aimed to probe into the associations among circular RNA ZFR (circ-ZFR), miR-130a/miR-107, and PTEN, and to investigate the regulatory mechanism of circ-ZFR‒miR-130a/miR-107‒PTEN axis in gastric cancer (GC). MATERIALS AND METHODS: GSE89143 microarray data used in the study were acquired from publicly available Gene Expression Omnibus database to identify differentially expressed circular RNAs inGC tissues. The expressions of circ-ZFR, miR-130a, miR-107, and PTEN were examined by real-time reverse transcription polymerase chain reaction, while PTEN protein expression was measured by western blot. The variation of GC cell proliferation and apoptosis was confirmed by cell counting kit-8 assay and flow cytometry analysis. The targeted relationships among circZFR, miR-130a/miR-107, and PTEN were predicted via bioinformatics analysis and demonstrated by dual-luciferase reporter assay and RNA immunoprecipitation assay. The impact of ZFR on gastric tumor was further verified in xenograft mice model experiment. RESULTS: Circ-ZFR and PTEN were low-expressed whereas miR-107 and miR-130a were highexpressed in GC tissues and cells. There existed targeted relationships and interactions between miR-130a/miR-107 and ZFR/PTEN. Circ-ZFR inhibited GC cell propagation, cell cycle and promoted apoptosis by sponging miR-107/miR-130a, while miR-107/miR-130a promoted GC cell propagation and impeded apoptosis through targeting PTEN. Circ-ZFR inhibited cell proliferation and facilitated apoptosis in GC by sponging miR-130a/miR-107 and modulating PTEN. Circ-ZFR curbed GC tumor growth and affected p53 protein expression in vivo. CONCLUSION: Circ-ZFR restrained GC cell proliferation, induced cell cycle arrest and promoted apoptosis by sponging miR-130a/miR-107 and regulating PTEN.