Circ0120816 acts as an oncogene of esophageal squamous cell carcinoma by inhibiting miR-1305 and releasing TXNRD1

Circular RNAs in Cell Cycle Regulation of Cancers

Cancer has been one of the most problematic health issues globally. Typically, all cancers share a common characteristic or cancer hallmark, such as sustaining cell proliferation, evading growth suppressors, and enabling replicative immortality. Indeed, cell cycle regulation in cancer is often found to be dysregulated, leading to an increase in aggressiveness. These dysregulations are partly due to the aberrant cellular signaling pathway. In recent years, circular RNAs (circRNAs) have been widely studied and classified as one of the regulators in various cancers. Numerous studies have reported that circRNAs antagonize or promote cancer progression through the modulation of cell cycle regulators or their associated signaling pathways, directly or indirectly. Mostly, circRNAs are known to act as microRNA (miRNA) sponges. However, they also hold additional mechanisms for regulating cellular activity, including protein binding, RNA-binding protein (RBP) recruitment, and protein translation. This review will discuss the current knowledge of how circRNAs regulate cell cycle-related proteins through the abovementioned mechanisms in different cancers.

CircSFMBT2 Plays an Oncogenic Role in Lung Adenocarcinoma Depending on the miR-1305/SALL4 Axis

Circular RNAs (circRNAs) exhibit significant functions in diverse malignant tumors, including lung adenocarcinoma (LUAD). In this study, we aimed to elucidate the role of circRNA scm like with four mbt domains 2 (circSFMBT2) in LUAD. Quantitative real-time polymerase chain reaction (qRT-PCR), western blot assay or immunohistochemistry (IHC) assay was performed for quantification of circSFMBT2, microRNA-1305 (miR-1305), spalt like transcription factor 4 (SALL4), proliferating Cell Nuclear Antigen (PCNA) or Ki-67. 5-ethynyl-2'-deoxyuridine (EdU) assay, transwell assay and flow cytometry analysis were applied to analyze cell proliferation, metastasis and apoptosis, respectively. Mouse xenograft model was established to explore the function of circSFMBT2. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were used to estimate the relationship between miR-1305 and circSFMBT2 or SALL4. CircSFMBT2 was upregulated in LUAD and related to advanced TNM stage and poor prognosis. CircSFMBT2 knockdown suppressed cell proliferation, metastasis, glycolysis and induced apoptosis in LUAD cells in vitro as well as tumor formation in vivo. CircSFMBT2 directly targeted miR-1305, and miR-1305 inhibition reversed circSFMBT2 knockdown-mediated inhibitory effects on LUAD malignant behaviors. SALL4 was the target gene of miR-1305. MiR-1305 overexpression repressed the malignant phenotypes of LUAD cells, while SALL4 enhancement abated the effects. CircSFMBT2 aggravated the progression of LUAD by the miR-1305/SALL4 axis, which might provide a diagnostic and prognostic marker for LUAD.

Role of ferroptosis in esophageal cancer and corresponding immunotherapy

Esophageal cancer (EC) is one of the most common digestive system malignancies in the world. The combined modality treatment of EC is usually surgery and radiation therapy, however, its clinical efficacy for advanced patients is relatively limited. Ferroptosis, a new type of iron-dependent programmed cell death, is different from apoptosis, necrosis and autophagy. In recent years, many studies have further enlightened that ferroptosis plays an essential role in the occurrence, development and metastasis of tumors. Targeting ferroptosis stimulates a new direction for further exploration of oncologic treatment regimens. Furthermore, ferroptosis has a critical role in the immune microenvironment of tumors. This paper reviews the mechanism of ferroptosis and the ferroptosis research progress in the treatment of EC. We further elaborate the interaction between ferroptosis and immunotherapy, and the related mechanisms of ferroptosis participation in the immunotherapy of EC, so as to provide new directions and ideas for the treatment of EC.

TXNRD1 knockdown inhibits the proliferation of endothelial cells subjected to oscillatory shear stress via activation of the endothelial nitric oxide synthase/apoptosis pathway

Atherosclerosis is the main cause of cardiovascular disease, and fluid shear stress is a key factor regulating its occurrence and development. Oscillatory shear stress (Oss) is an important pro-atherosclerosis factor. Oss mainly occurs in areas that are susceptible to atherosclerosis, but the exact mechanism of atherosclerosis induction remains unclear. Therefore, starting from the atheroprone phenotype that Oss stimulates abnormal vascular endothelial cell proliferation, this study aimed to reveal the underlying mechanism of Oss-induced atherosclerosis formation and to identify new targets for the prevention and treatment of atherosclerosis. In this study, the gene encoding thioredoxin reductase 1 (TXNRD1), which is closely related to atherosclerosis development and cell proliferation, was screened by analyzing the transcriptome sequencing data of static and Oss-treated human aortic endothelial cells (HAECs). Moreover, this study successfully verified that TXNRD1 mRNA and protein were significantly upregulated in Oss-treated HAECs. Oss significantly promoted the proliferation, migration, and tube formation of HAECs, whereas TXNRD1 knockdown impaired the proliferation, migration, and tube formation of Oss-treated HAECs, and this process was mainly achieved via activation of the apoptosis pathway. To further clarify whether Oss-sensitive TXNRD1 affects the apoptosis rate and proliferative ability of HAECs by regulating the endothelial nitric oxide synthase (eNOS) pathway, we used NG-nitro-L-arginine methyl ester (L-NAME) to inhibit eNOS activity and nitric oxide (NO) production. L-NAME significantly reversed the promoting effect of TXNRD1 knockdown on Oss-treated HAEC apoptosis, and it also abolished the inhibitory effect of TXNRD1 knockdown on the proliferation and S + G2 phase cell mass of Oss-treated HAECs. In conclusion, this study showed that TXNRD1 knockdown inhibited the proliferation of HAECs exposed to Oss by activating the eNOS/apoptosis pathway, revealing that TXNRD1 is involved in the dysregulation of Oss-induced endothelial cell proliferation. These findings provide new directions and insights into the prevention and treatment of atherosclerosis.

Circ_0058063 regulates the development of esophageal cancer through miR-377-3p/HOXA1 axis

Esophageal cancer is one of the deadliest cancers. Circular RNA (CircRNA) can be used as a tumor marker. Therefore, this provides an important idea for our research. Real-time quantitative PCR (RT-qPCR) was used to analyze the expression of circ_0058063, miR-377-3p and homeobox protein Hox-A1 (HOXA1), western blot was used to analyze the protein levels of HOXA1 and cyclinD1, B cell leukemia/lymphoma 2 associated X (Bax). Cell Counting Kit-8 (CCK-8) assay, colony formation assay and wound healing assay were used to analyze cell proliferation and migration; apoptosis was analyzed by flow cytometry. Dual-luciferase reporter assays were performed to analyze the luciferase activities. Transwell assay was used to analyze the cell invasion. A glycolysis metabolism assay was used to analyze cell glycolysis ability. Xenograft models were used to validate the effect of circ_0009035 in the growth of esophageal cancer in vivo . Circ_0009035 and HOXA1 were upregulated, while miR-377 was downregulated in esophageal cancer.. Circ_0058063 targeted miR-377-3p, and HOX4 was a target of miR-377-3p. Knockdown of circ_0058063 inhibited migration, invasion and proliferation and promoted apoptosis of esophageal cancer cells. MiR-377-3p inhibition or HOXA1 overexpression could restore the effect of si-circ_0058063 on esophageal cancer cells. Knockdown of circ_0058063 repressed the growth of esophageal cancer tumors in vivo. Our study found that circ_0058063 could regulate the expression of HOXA1 by targeting miR-377-3p, thereby affecting the progress of esophageal cancer.

Ferroptosis and cuproptosis prognostic signature for prediction of prognosis, immunotherapy and drug sensitivity in hepatocellular carcinoma: development and validation based on TCGA and ICGC databases

Background

Hepatocellular carcinoma (HCC) is a common malignancy. Ferroptosis and cuproptosis promote HCC spread and proliferation. While fewer studies have combined ferroptosis and cuproptosis to construct prognostic signature of HCC. This work attempts to establish a novel scoring system for predicting HCC prognosis, immunotherapy, and medication sensitivity based on ferroptosis-related genes (FRGs) and cuproptosis-related genes (CRGs).

Methods

FerrDb and previous literature were used to identify FRGs. CRGs came from original research. The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) databases included the HCC transcriptional profile and clinical information [survival time, survival status, age, gender, Tumor Node Metastasis (TNM) stage, etc.]. Correlation, Cox, and least absolute shrinkage and selection operator (LASSO) regression analyses were used to narrow down prognostic genes and develop an HCC risk model. Using "caret", R separated TCGA-HCC samples into a training risk set and an internal test risk set. As external validation, we used ICGC samples. We employed Kaplan-Meier analysis and receiver operating characteristic (ROC) curve to evaluate the model's clinical efficacy. CIBERSORT and TIMER measured immunocytic infiltration in high- and low-risk populations.

Results

TXNRD1 [hazard ratio (HR) =1.477, P<0.001], FTL (HR =1.373, P=0.001), GPX4 (HR =1.650, P=0.004), PRDX1 (HR =1.576, P=0.002), VDAC2 (HR =1.728, P=0.008), OTUB1 (HR =1.826, P=0.002), NRAS (HR =1.596, P=0.005), SLC38A1 (HR =1.290, P=0.002), and SLC1A5 (HR =1.306, P<0.001) were distinguished to build predictive model. In both the model cohort (P<0.001) and the validation cohort (P<0.05), low-risk patients had superior overall survival (OS). The areas under the curve (AUCs) of the ROC curves in the training cohort (1-, 3-, and 5-year AUCs: 0.751, 0.727, and 0.743), internal validation cohort (1-, 3-, and 5-year AUCs: 0.826, 0.624, and 0.589), and ICGC cohort (1-, 3-, and 5-year AUCs: 0.699, 0.702, and 0.568) were calculated. Infiltration of immune cells and immunological checkpoints were also connected with our signature. Treatments with BI.2536, Epothilone.B, Gemcitabine, Mitomycin.C, Obatoclax. Mesylate, and Sunitinib may profit high-risk patients.

Conclusions

We analyzed FRGs and CRGs profiles in HCC and established a unique risk model for treatment and prognosis. Our data highlight FRGs and CRGs in clinical practice and suggest ferroptosis and cuproptosis may be therapeutic targets for HCC patients. To validate the model's clinical efficacy, more HCC cases and prospective clinical assessments are needed.

Knockdown of circ_0004585 enhances the chemosensitivity of colorectal cancer cells to 5-fluorouracil via the miR-874-3p/CCND1 axis

BACKGROUND

Colorectal cancer (CRC) is a serious threat to human health and is drug-resistant. Circular RNA _0004585 (circ_0004585) has been shown to be expressed in CRC, but whether it plays a role in CRC with chemoresistance remains unknown. Therefore, this study aimed to investigate the potential role of circ_0004585 in CRC with 5-fluorouracil (5-FU) resistance.

METHODS

The expression of related genes was detected by quantitative real-time polymerase chain reaction (qRT-PCR), and the protein expressions of cleaved caspase-3, cleaved caspase-9, and cyclin D1 (CCND1) were detected by western blot. Cell functions were identified using CCK-8, colony formation, flow cytometry, tube formation and transwell assays. The putative relationships between miR-874-3p and circ_0004585 or CCND1 were validated by dual-luciferase reporter assays. Animal experiments were conducted to verify the effect of circ_0004585 on 5-FU resistance in vivo.

RESULTS

Circ_0004585 was highly expressed in CRC tissues and cells, particularly in 5-FU-resistant CRC tissues and cells. Circ_0004585 knockdown enhanced 5-FU sensitivity to further inhibit CRC cell viability, colony formation, cell migration and invasion, and accelerate cell apoptosis. MiR-874-3p was the target of circ_0004585, and miR-874-3p depletion partially recovered the malignant behaviors of 5-FU-resistant CRC cells that were blocked by silencing of circ_0004585. In addition, CCND1 was the target of miR-874-3p, and overexpression of CCND1 was able to restore the malignant effects of 5-FU-resistant CRC cells that were repressed by miR-874-3p enrichment. Animal experiments confirmed that circ_0004585 knockdown inhibited the growth of CRC tumors and enhanced 5-FU sensitivity in vivo.

CONCLUSION

Circ_0004585 promotes the development of CRC and increases 5-FU resistance in CRC through the miR-874-3p/CCND1 axis. These results suggest that circ_0004585 may be a therapeutic target for 5-FU-ressitant CRC.

Circ_0061395 functions as an oncogenic gene in hepatocellular carcinoma by acting as a miR-1182 sponge

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in liver cancer, with a high rate of metastasis and recurrence. Circular RNA_0061395 (circ_0061395) has been shown to be involved in the advance of HCC. However, the interaction between circ_0061395 and microRNA (miRNA) in HCC has not been studied. Quantitative real-time polymerase-chain reaction (qRT-PCR) was used to detect the expression of related genes in liver cancer tissues and cells. The stability of circ_0061395 was verified by RNase R digestion. Through detection of cell malignant behavior and apoptosis, the capping experiment was carried out to verify the regulatory relationship between miR-1182 and circ_0061395 or SPARC/osteonectin, CWCV and Kazal-like domains proteoglycan 1 (SPOCK1). The expression of related proteins was detected by western blot. The interaction of miR-1182 with circ_0061395 or SPOCK1 has been notarized by Dual-luciferase reporter analysis and RNA immunoprecipitation (RIP) assay. Xenotransplantation experiments using BALB/C nude mice were used to confirm the function of circ_0061395 in vivo. Circ_0061395 and SPOCK1 were significantly expressed in liver cancer tissues and cells. Silencing circ_0061395 reduced the proliferation, migration, invasion, tube formation and tumor spheroid formation rate of Huh-7 and SNU-387 cells. MiR-1182 was a target of circ_0061395. Silencing circ_0061395 inhibited the malignant behavior of HCC cells by releasing miR-1182. In addition, SPOCK1 was the target of miR-1182. Overexpression of SPOCK1 partially restored the inhibitory effect of miR-1182 on cell proliferation. Animal experiments confirmed the anti-tumor effect of silence circ_0061395. Circ_0061395 induced the changes of the expression of SPOCK1 by regulating miR-1182, thereby mediating the process of HCC, and at least partially promoting the development of HCC cells, providing a novel targeted therapy for HCC.

Circular RNA circ_0007841 participates in progression of nonsmall cell lung cancer via miR-199a-5p/SphK2 axis

CircRNAs have been found to be participated in the development of numerous cancers. Nevertheless, the role of circRNAs in the progression of nonsmall cell lung cancer (NSCLC) has not been fully made clear. The purpose of our study was to study and understand the mechanism of circ_0007841 regulating the progression of NSCLC. NSCLC tissue samples and adjacent normal tissue samples used were obtained from 53 NSCLC patients. The expressions of circ_0007841, miR-199a-5p and SphK2 in all samples were detected by the real-time quantitative PCR. Then luciferase reporter gene assay and RNA immunoprecipitation (RIP) assay were used to analyze the relevance between circ_0007841, miR-199a-5p and SphK2. Cell Counting Kit-8, colony-forming, thymidine analog 5-ethynyl-2'-deoxyuridine assays, and transwell assay detect the effects of these three biomolecules on NSCLC carcinogenesis by western blot. We evaluate the effect of circ_0007841 on the growth of NSCLC by establishing the xenograft mice model. Experimental studies have shown that the higher expression of circ_0007841 in NSCLC tissues, and circ_0007841 strengthen cell viability, cell proliferation and cell adhesion. In addition, miR-199a-5p exerts an inhibitory effect in NSCLC cells by inhibiting SphK2. And Sphk2 regulates cell proliferation and adhesion. In addition, in-vivo silencing of circ_0007841 was found to inhibit the growth of NSCLC tumors. This research demonstrated that circ_0007841 had a positive influence in improving NSCLC development by targeting miR-199a-5p and upregulating oncogene SphK2.

circRNA: A New Biomarker and Therapeutic Target for Esophageal Cancer

Circular RNAs (circRNAs) comprise a large class of endogenous non-coding RNA with covalently closed loops and have independent functions as linear transcripts transcribed from identical genes. circRNAs are generated by a “back-splicing” process regulated by regulatory elements in cis and associating proteins in trans. Many studies have shown that circRNAs play important roles in multiple processes, including splicing, transcription, chromatin modification, miRNA sponges, and protein decoys. circRNAs are highly stable because of their closed ring structure, which prevents them from degradation by exonucleases, and are more abundant in terminally differentiated cells, such as brains. Recently, it was demonstrated that numerous circRNAs are differentially expressed in cancer cells, and their dysfunction is involved in tumorigenesis and metastasis. However, the crucial functions of these circRNAs and the dysregulation of circRNAs in cancer are still unknown. In this review, we summarize the recent reports on the biogenesis and biology of circRNAs and then catalog the advances in using circRNAs as biomarkers and therapeutic targets for cancer therapy, particularly esophageal cancer.

Current advances and future perspectives on the functional roles and clinical implications of circular RNAs in esophageal squamous cell carcinoma: more influential than expected

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive gastrointestinal cancers with high incidence and mortality. Therefore, it is necessary to identify novel sensitive and specific biomarkers for ESCC detection and treatment. Circular RNAs (circRNAs) are a type of noncoding RNAs featured by their covalently closed circular structure. This special structure makes circRNAs more stable in mammalian cells, coupled with their great abundance and tissue specificity, suggesting circRNAs may present enormous potential to be explored as valuable prognostic and diagnostic biomarkers for tumor. Mounting studies verified the critical roles of circRNAs in regulating ESCC cells malignant behaviors. Here, we summarized the current progresses in a handful of aberrantly expressed circRNAs, and elucidated their biological function and clinical significance in ESCC, and introduced a series of databases for circRNA research. With the improved advancement in high-throughput sequencing and bioinformatics technique, new frontiers of circRNAs will pave the path for the development of precision treatment in ESCC.

Exosomal circRNA FNDC3B promotes the progression of esophageal squamous cell carcinoma by sponging miR-490-5p and regulating thioredoxin reductase 1 expression

Exosomal circular RNAs (circRNAs) have been reported to play critical roles in esophageal squamous cell carcinoma (ESCC). We aimed to investigate the function of exosomal circRNA FNDC3B (circFNDC3B). The RNA levels and protein levels were examined using RT-qPCR and western blot (WB) assays. Colony formation and EdU assays were used to assess cell proliferative ability. Cell migratory and invasive abilities were detected by wound healing and transwell assays. Cell apoptosis was measured by flow cytometry. Glycolysis was measured using commercial kits. Transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) were applied to examine the morphology and size of exosomes. Dual-luciferase reporter, RIP and RNA pull-down assays assessed the interaction of miR-490-5p with circFNDC3B or thioredoxin reductase 1 (TXNRD1). Xenograft tumor model determined the role of exosomal circFNDC3B in vivo. We observed that circFNDC3B was upregulated in ESCC samples and cells, as well as ESCC-derived exosomes. CircFNDC3B could be delivered via exosomes in tumor cells, and the colony formation, proliferation, migration, invasion, glycolysis, and in vivo growth ability of recipient cells were weakened after co-incubation with exosomal circFNDC3B-knockdown donor cells. CircFNDC3B was a miR-490-5p sponge, and miR-490-5p inhibition reversed the role of exosomal circFNDC3B-downregulating in ESCC cells. TXNRD1 was a miR-490-5p target, and TXNRD1 elevation weakened the anti-cancer function of miR-490-5p upregulation in ESCC cells. CircFNDC3B mediated TXNRD1 expression by interacting with miR-490-5p. In conclusion, exosomal circFNDC3B drove ESCC progression via regulating the miR-490-5p/TXNRD1 axis.AbbreviationsEC: esophageal cancer; ESCC: esophageal squamous cell carcinoma; circRNA: circular RNA; WB: western blot; TEM: transmission electron microscopy; NTA: nanoparticle tracking analysis; TXNRD1: thioredoxin reductase 1; IHC: immunohistochemistry; RT-qPCR: reverse transcription-polymerase quantitative chain reaction; GLUT1: glucose transport protein type 1; LDHA: lactate dehydrogenase A.

Circular RNAs With Efficacy in Preclinical In Vitro and In Vivo Models of Esophageal Squamous Cell Carcinoma

Esophageal cancer is associated with a dismal prognosis. The armamentarium of approved drugs is focused on chemotherapy with modest therapeutic benefit. Recently, checkpoint inhibitory monoclonal antibody Pembrolizumab was approved. In order to identify new targets and modalities for the treatment of esophagus squamous cell carcinoma (ESCC) we searched the literature for circRNAs involved in the pathogenesis of ESCC. We identified two down-regulated and 17 up-regulated circRNAs as well as a synthetic circRNA with efficacy in preclinical in vivo systems. Down-regulated circRNAs sponge microRNAs directed against tumor suppressor genes. Up-regulated circRNAs sponge microRNAs directed against mRNAs, which encode proteins with pro-tumoral functions. We discuss issues such as reconstitution of down-regulated circRNAs and inhibition of up-regulated circRNAs with short interfering RNA (siRNA)- related entities. Also, we address druggability issues of the identified targets.

Resveratrol Contrasts IL-6 Pro-Growth Effects and Promotes Autophagy-Mediated Cancer Cell Dormancy in 3D Ovarian Cancer: Role of miR-1305 and of Its Target ARH-I

Tumor dormancy is the extended period during which patients are asymptomatic before recurrence, and it represents a difficult phenomenon to target pharmacologically. The relapse of tumors, for instance arising from the interruption of dormant metastases, is frequently observed in ovarian cancer patients and determines poor survival. Inflammatory cytokines present in the tumor microenvironment likely contribute to such events. Cancer cell dormancy and autophagy are interconnected at the molecular level through ARH-I (DIRAS3) and BECLIN-1, two tumor suppressors often dysregulated in ovarian cancers. IL-6 disrupts autophagy in ovarian cancer cells via miRNAs downregulation of ARH-I, an effect contrasted by the nutraceutical protein restriction mimetic resveratrol (RV). By using three ovarian cancer cell lines with different genetic background in 2D and 3D models, the latter mimicking the growth of peritoneal metastases, we show that RV keeps the cancer cells in a dormant-like quiescent state contrasting the IL-6 growth-promoting activity. Mechanistically, this effect is mediated by BECLIN-1-dependent autophagy and relies on the availability of ARH-I. We also show that ARH-I (DIRAS3) is a bona fide target of miR-1305, a novel oncomiRNA upregulated by IL-6 and downregulated by RV. Clinically relevant, bioinformatic analysis of a transcriptomic database showed that the high expression of DIRAS3 and MAP1LC3B mRNAs together with that of CDKN1A, directing a cellular dormant phenotype, predicts better overall survival in ovarian cancer patients, and this correlates with MIR1305 downregulation. The possibility of maintaining a permanent cell dormancy in ovarian cancer by the chronic administration of RV should be considered as a therapeutic option to prevent the "awakening" of cancer cells in response to a permissive microenvironment, thus limiting the risk of tumor relapse and metastasis.

Regulation of ferroptosis by noncoding RNAs: a novel promise treatment in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a highly prevalent tumor that requires extensive research. Ferroptosis is a unique cell death modality driven by iron-dependent phospholipid peroxidation manifested as an accumulation of lipid-reactive oxygen species. With further understanding of noncoding RNAs (ncRNAs), numerous studies have demonstrated an important regulatory role of ncRNAs in ESCC through ferroptosis, including microRNAs, long ncRNAs, and circular RNAs. These ncRNAs influence the expression of the target gene to regulate ESCC progression by involving the ferroptosis signaling pathway. However, the specific regulatory mechanism of ncRNAs on ferroptosis in ESCC remains largely unknown. This review summarized the current knowledge on the relation between ferroptosis regulators, such as glutathione synthesis/metabolism, Keap1/Nfr2, and p53, by ncRNAs and ESCC. This review also proposed the possible therapeutic approaches for ncRNAs targeting ferroptosis in ESCC. This is the latest and most effective summary of recent research achievements of ncRNAs on ferroptosis in ESCC. These ncRNAs based on ferroptosis merit further investigation in preclinical research of ESCC.

Hsa_circ_0072008 regulates cell proliferation, migration, and invasion in cervical squamous cell carcinoma via miR-1305/helicase, lymphoid specific (HELLS) axis

Cervical squamous cell carcinoma (CESC) is one of the most common cancers in women. Recent studies have proved that circular RNAs (circRNAs) could regulate the progress of CESC, but the mechanism is still indistinct. In this work, we explored the roles of circ_0072008 in CESC. The expression levels of circ_0072008, microRNA-1305 (miR-1305) and mRNA of HELLS (helicase, lymphoid specific) were detected by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) in CESC tissues. Meanwhile, the level of HELLS was quantified by western blot analysis. Besides, the cell functions were examined by colony formation assay, 5-Ethynyl-2’-deoxyuridine (EdU) assay, wound healing assay, flow cytometry assay and western blot. Furthermore, the interaction between miR-1305 and circ_0072008 or HELLS was detected by dual-luciferase reporter assay. The function of circ_0072008 in CESC has also been further verified in vivo by xenograft model experiments. The levels of circ_0072008 and HELLS were upregulated, and the miR-1305 level was decreased in CESC tissues in contrast to that in normal tissues. For functional analysis, silencing circ_0072008 inhibited cell proliferation and cell migration, whereas enhanced cell apoptosis in CESC cells. In mechanism, circ_0072008 acted as a miR-1305 sponge to regulate the level of HELLS. Moreover, miR-1305 was confirmed to repress the progression of CESC cells by suppressing HELLS. Meanwhile, knockdown of circ_0072008 inhibited CESC cells growth in vivo. In conclusion, circ_0072008 facilitated CESC cell proliferation, migration, and invasion through increasing HELLS expression by regulating miR-1305, which also offered an underlying targeted therapy for CESC treatment.

Circ_0078710 promotes the development of liver cancer by upregulating TXNDC5 via miR-431-5p

INTRODUCTION AND OBJECTIVES

Liver cancer, with high recurrence and metastasis rate, is a common malignant tumor. Circular RNA_0078710 (circ_0078710) has been shown to be take part in the advance of hepatocellular carcinoma. However, the interaction between circ_0091579 and microRNA-431-5p (miR-431-5p) in liver cancer has not been studied.

MATERIALS AND METHODS

The expressions of circ_0078710, miR-431-5p and Thioredoxin domain-containing 5 (TXNDC5) in liver cancer tissues and cells were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The effect of cric_0078710 in liver cancer cells was assessed by Cell Counting Kit-8 (CCK-8) assay, Transwell, flow cytometry and Dual-luciferase reporter assay. Glycolysis metabolism was examined by lactate production, glucose uptake and ATP level. The protein levels of ki-67, bax and TXNEC5 were tested by western blot. The role of circ_0078710 in vivo was determined by animal study.

RESULTS

Circ_0078710 and TXNDC5 were notably expressed in liver cancer tissues and cells. Circ_0078710 knockdown diminished proliferation, migration, invasion and glycolytic metabolism of huh7 and Hep3B cells, and accelerated cell apoptosis. MiR-431-5p is the target of circ_0078710, and silence circ_0078710 can inhibit the malignant behavior and glycolysis of hepatocellular carcinoma (HCC) cells by releasing miR-431-5p. In addition, TXNDC5 was a target of miR-431-5p, and overexpression of TXNDC5 restored cell proliferation and glycolysis inhibition due to miR-431-5p. Animal experiments made clear the anti-tumor effect of circ_0078710 knockdown.

CONCLUSION

Circ_0078710 promotes the progression of liver cancer by regulating TXNDC5 expression by targeting miR-431-5p. These results demonstrate that circ_0078710 could be a remedy target for liver cancer.

Circular RNA circ_0008934 promotes hepatocellular carcinoma growth and metastasis through modulating miR-1305/TMTC3 axis

Circular RNAs (circRNAs) play important roles in the progression of hepatocellular carcinoma (HCC). However, the exact function of circ_0008934 in HCC is unknown. Our study aimed to investigate the expression characteristics of circ_0008934 in HCC and its effects on the proliferation and metastasis of HCC, and to explore the potential mechanism. In this study, circ_0008934 expression was found to be significantly upregulated in HCC tissues and cell lines by qRT-PCR. High level of circ_0008934 is closely associated with higher serum AFP (P < 0.001), larger tumor diameter (P = 0.012), microvascular invasion (P = 0.008) and poorer prognosis (P = 0.007) of HCC patients. Functionally, knockdown of circ_0008934 inhibited HCC cell proliferation, invasion and migration in vitro and vivo. Mechanically, circ_0008934 was a sponge of miR-1305 to facilitate the TMTC3 expression, and the TMTC3 expression in HCC tissues was negatively associated with the survival of HCC patients. Furthermore, rescued assays revealed that the circ_0008934 facilitated HCC proliferation, invasion and migration by regulating miR-1305/ TMTC3 signaling pathways. Overall, these results demonstrate that downregulation of circ_0008934 repress HCC growth and metastasis by upregulating miR-1305 to inhibit TMTC3, suggesting circ_0008934/ miR-1305/ TMTC3 regulatory axis may be a possible novel therapeutic target for HCC.

The expression of circ_0090049 in hepatocellular carcinoma and the molecular regulation mechanism of other biological functions

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in liver cancer. Circular RNA_0090049 (circ_0090049) has been shown to be involved in the advance of HCC. However, the interaction between circ_0090049 and microRNA (miRNA) in HCC has not been studied. Quantitative real-time PCR was used to detect the expression of related genes. Through detection of cell proliferation, migration, invasion, and rate of tumor sphere formation, the capping experiment was carried out to verify the regulatory relationship between miRNA and circ_0090049 or circ_0090049 and ubiquitin-conjugating enzyme E2 T (UBE2T). The expression of related proteins was detected by Western blotting. The interaction of miRNA with circ_0090049 or UBE2T was notarized by Dual-luciferase reporter assay. Xenotransplantation experiments confirmed the function of circ_0090049 in vivo. Circ_0090049 and UBE2T were upregulated in liver cancer. Silencing circ_0090049 reduced the proliferation, migration, invasion, and tumor spheroid formation rate of Huh7 and HCCLM3 cells. MiR-605-5p and miR-548c-3p were identified as targets of circ_0090049, and UBE2T was the target of miR-605-5p and miR-548c-3p. Anti-miR-605-5p, anti-miR-548c-3p or UBE2T overexpression restored the inhibitory effect of circ_0090049 knockdown on HCC cells. Animal experiments confirmed the antitumor effect of silence circ_0090049. Circ_0090049 regulates the expression of UBE2T by regulating miR-605-5p or miR-548c-3p, thereby promoting the development of HCC cells.