Genome-Wide Analysis of the Expression of Circular RNA Full-Length Transcripts and Construction of the circRNA-miRNA-mRNA Network in Cervical Cancer

Current advances in circular RNA detection and investigation methods: Are we running in circles?

Circular RNAs (circRNAs), characterized by their closed-loop structure, have emerged as significant transcriptomic regulators, with roles spanning from microRNA sponging to modulation of gene expression and potential peptide coding. The discovery and functional analysis of circRNAs have been propelled by advancements in both experimental and bioinformatics tools, yet the field grapples with challenges related to their detection, isoform diversity, and accurate quantification. This review navigates through the evolution of circRNA research methodologies, from early detection techniques to current state-of-the-art approaches that offer comprehensive insights into circRNA biology. We examine the limitations of existing methods, particularly the difficulty in differentiating circRNA isoforms and distinguishing circRNAs from their linear counterparts. A critical evaluation of various bioinformatics tools and novel experimental strategies is presented, emphasizing the need for integrated approaches to enhance our understanding and interpretation of circRNA functions. Our insights underscore the dynamic and rapidly advancing nature of circRNA research, highlighting the ongoing development of analytical frameworks designed to address the complexity of circRNAs and facilitate the assessment of their clinical utility. As such, this comprehensive overview aims to catalyze further advancements in circRNA study, fostering a deeper understanding of their roles in cellular processes and potential implications in disease. This article is categorized under: RNA Methods > RNA Nanotechnology RNA Methods > RNA Analyses in Cells RNA Methods > RNA Analyses In Vitro and In Silico.

Pan-cancer analysis reveals correlation between RAB3B expression and tumor heterogeneity, immune microenvironment, and prognosis in multiple cancers

RAB3B is essential for the transportation and secretion within cells. Its increased expression is linked to the development and progression of various malignancies. However, understanding of RAB3B's involvement in carcinogenesis is mostly limited to specific cancer subtypes. Hence, exploring RAB3B's regulatory roles and molecular mechanisms through comprehensive cancer datasets might offer innovative approaches for managing clinical cancer. To examine the potential involvement of RAB3B in the development of cancer, we analyzed data from various sources including The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression Project (GTEx), cBioPortal, HPA, UALCAN, and tissue microarray (TAM). Using bioinformatics techniques, we examined the correlation between RAB3B expression and prognosis, tumor heterogeneity, methylation modifications, and immune microenvironment across different cancer types. Our findings indicate that elevated RAB3B expression can independently predict prognosis in many tumors and has moderate accuracy for diagnosing most cancers. In most cancer types, we identified RAB3B mutations that showed a significant correlation with tumor mutational burden (TMB), mutant-allele tumor heterogeneity (MATH), and microsatellite instability (MSI). Abnormal DNA methylation patterns were also observed in most cancers compared to normal tissues. Additionally, we found significant correlations between RAB3B expression, immune cell infiltration, and immune scores across various cancers. Through pan-cancer analysis, we observed significant differences in RAB3B expression levels between tumors and normal tissues, making it a potential primary factor for cancer diagnosis and prognosis. The IHC results revealed that the expression of RAB3B in six types of tumors was consistent with the results of the pan-cancer analysis of the database. Furthermore, RAB3B showed potential associations with tumor heterogeneity and immunity. Thus, RAB3B can be utilized as an auxiliary diagnostic marker for early tumor detection and a prognostic biomarker for various tumor types.

CircIFFO1 suppresses tumor growth and metastasis of cutaneous squamous cell carcinoma by targeting the miR-424-5p/NFIB axis

Cutaneous squamous cell carcinoma (CSCC) is a severe malignancy derived from the skin. Circular RNAs (circRNAs) play an important role in the pathological process of many malignant tumors. Moreover, circIFFO1 is reported to be down-regulated in CSCC tissues compared with non-lesional skin tissues. This study aimed to explore the specific role and potential mechanism of circIFFO1 in CSCC progression. Cell proliferation ability was analyzed by 3-(4, 5-dimethylthiazol-2-y1)-2,5-diphenyl tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU) incorporation, and colony-formation assays. Cell cycle progression and apoptosis were detected by flow cytometry. Cell migration and invasion were examined by transwell assays. The interaction between microRNA-424-5p (miR-424-5p) and circIFFO1 or nuclear factor I/B (NFIB) was validated by dual-luciferase reporter, RNA pull-down, and RNA immunoprecipitation (RIP) assays. Xenograft tumor assay and immunohistochemistry (IHC) assay were employed to analyze the tumorigenesis in vivo. CircIFFO1 level was down-regulated in CSCC tissues and cell lines. CircIFFO1 overexpression suppressed the proliferation, migration, invasion, and promoted apoptosis of CSCC cells. CircIFFO1 acted as a molecular sponge for miR-424-5p. The anti-tumor effects mediated by circIFFO1 overexpression in CSCC cells could be reversed by miR-424-5p overexpression. miR-424-5p interacted with the 3' untranslated region (3'UTR) of Nuclear Factor I/B (NFIB). miR-424-5p knockdown suppressed the malignant behaviors of CSCC cells, and NFIB knockdown counteracted the anti-tumor effects of miR-424-5p absence in CSCC cells. Additionally, circIFFO1 overexpression restrained xenograft tumor growth in vivo. CircIFFO1 suppressed the malignant behaviors of CSCC by mediating the miR-424-5p/NFIB axis, which provided new insights into the pathogenesis of CSCC.

Genome-wide perturbations of A-to-I RNA editing dysregulated circular RNAs promoting the development of cervical cancer

Cervical cancer, the second most common female malignant tumor, seriously threatens women's health and lives. Despite the availability of the HPV vaccine, effective treatment options for cervical cancer are still lacking. New research perspectives now clarify that RNA editing dysregulation and changes in circRNA expression are jointly involved in disease pathogenesis, so molecular changes associated with circRNA and RNA editing may provide clues for the development of new therapeutic strategies for cervical cancer. In this study, we designed a series of pipelines to identify and analyze dysregulated RNA editing events in circRNAs. Our findings indicate a decrease in A-to-I RNA editing levels in cervical cancer compared to normal tissues, and editing may influence the back-splicing process of circRNAs through structural modifications of Alu elements. Moreover, our research reveals that RNA editing could modulate circRNA biogenesis by influencing RNA binding protein (RBP) binding on a transcriptome-wide scale, as well as influence the expression and coding potential of circRNAs. Importantly, we identified three RNA editing sites that could serve as potential biomarkers. In summary, our study presents a comprehensive landscape of RNA editing perturbations in circRNAs, providing new insights into the complex relationship between RNA editing and circRNA dysregulation in cervical cancer.

circ_0000337 Promotes the Progression of Cervical Cancer by miR-155-5p/RAB3B Axis

Current study aims to investigate the biological function of circular RNA (circRNA, circ_0000337) in cervical cancer (CC). Bioinformatic analyses were used to predict targets for circ_0000337 and miR-155-5p, and analyze the gene expression differences between cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) tissues and normal tissues. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were applied to assess mRNA and protein expressions of circ_0000337, microRNA-155-5p (miR-155-5p) and member RAS oncogene family (RAB3B), respectively. Following the establishment of gain/loss-of-function models, CCK-8 was performed to evaluate cell proliferation. Bioinformatics analysis, dual-luciferase reporter assay and RNA immunoprecipitation (RIP) were used to identify the interaction in circ_0000337, miR-155-5p, and RAB3B. Circ_0000337 and RAB3B were upregulated, while miR-155-5p was downregulated in CC tissues and cell lines. circ_0000337 overexpression promoted cell proliferation, circ_0000337 knock down inhibited cell proliferation by sponging miR-155-5p. RAB3B was a target of miR-155-5p which was positively regulated by circ_0000337. In the collected CC tissues, there was a negative correlation between miR-155-5p and circ_0000337 or RAB3B, and a positive correlation between circ_0000337 and RAB3B. miR-155-5p was positively, while RAB3B was negatively correlated with OS in patients with CC, and they were negatively correlated. In conclusion, circ_0000337 upregulates RAB3B by sponging miR-155-5p to promote CC cell proliferation.

The critical role of circular RNAs in drug resistance in gastrointestinal cancers

Nowadays, drug resistance (DR) in gastrointestinal (GI) cancers, as the main reason for cancer-related mortality worldwide, has become a serious problem in the management of patients. Several mechanisms have been proposed for resistance to anticancer drugs, including altered transport and metabolism of drugs, mutation of drug targets, altered DNA repair system, inhibited apoptosis and autophagy, cancer stem cells, tumor heterogeneity, and epithelial-mesenchymal transition. Compelling evidence has revealed that genetic and epigenetic factors are strongly linked to DR. Non-coding RNA (ncRNA) interferences are the most crucial epigenetic alterations explored so far, and among these ncRNAs, circular RNAs (circRNAs) are the most emerging members known to have unique properties. Due to the absence of 5' and 3' ends in these novel RNAs, the two ends are covalently bonded together and are generated from pre-mRNA in a process known as back-splicing, which makes them more stable than other RNAs. As far as the unique structure and function of circRNAs is concerned, they are implicated in proliferation, migration, invasion, angiogenesis, metastasis, and DR. A clear understanding of the molecular mechanisms responsible for circRNAs-mediated DR in the GI cancers will open a new window to the management of GI cancers. Hence, in the present review, we will describe briefly the biogenesis, multiple features, and different biological functions of circRNAs. Then, we will summarize current mechanisms of DR, and finally, discuss molecular mechanisms through which circRNAs regulate DR development in esophageal cancer, pancreatic cancer, gastric cancer, colorectal cancer, and hepatocellular carcinoma.

Comprehensive profile and contrastive analysis of circular RNA expression in cervical squamous carcinoma and adenocarcinoma

Background

Numerous studies have shown circular RNA (circRNA) dysregulation is associated with the pathogenesis of cervical cancer,particularly in individual carcinoma variants. The aim of this study is to investigate and contrastively analyze the expression pattern of circRNAs in cervical squamous carcinoma and adenocarcinoma mediated by human papillomavirus type 16 (HPV-16).

Methods

The expression of circRNAs in cervical squamous carcinoma (SCC), adenocarcinoma (ADC) and adenosquamous carcinoma (ASC) tissues, together with the adjacent normal tissues (ANT), was profiled by high-throughput RNA sequencing (RNA-seq). Bioinformatics analysis and quantitative real time polymerase chain reaction (qRT-PCR) validation of the sequencing data were performed. A network of circRNA-miRNA (microRNA)-mRNA was then constructed according to predicted targets and function of candidate circRNAs.

Results

A total of 11,685 annotated circRNAs were identified in six cervical samples. There were 42 up-regulated and 98 down-regulated circRNAs. 215 circRNAs were up-regulated in SCC but down-regulated circRNAs in ADC, while 50 circRNAs displayed the opposite trend. Function enrichment analysis based on different expressions of circRNAs found that the most enriched pathway in all the three pathologic variants of cervical cancer was the "ubiquitin mediated proteolysis" pathway. Eight key candidate circRNAs derived from this pathway were further validated, and we noticed that several target miRNAs of candidate circRNAs could target the source genes. Based on this we constructed a related competing endogenous RNA (ceRNA) network.

Conclusion

Through a comprehensive interpretation of differentially expressed circRNAs in different pathologic variants of cervical cancer, this study provides new insights into the process of tumor differentiation mediated by HPV. Our results may help to complement the molecular typing and stem cell theory of cervical cancer.

A Novel PiRNA Enhances CA19-9 Sensitivity for Pancreatic Cancer Identification by Liquid Biopsy

Pancreatic cancer is one of the deadliest tumours worldwide, and its poor prognosis is due to an inability to detect the disease at the early stages, thereby creating an urgent need to develop non-invasive biomarkers. P-element-induced wimpy testis (PIWI) proteins work together with piwi-interacting RNAs (piRNAs) to perform epigenetic regulation and as such hold great potential as biomarkers for pancreatic cancer. PIWIL2 and PIWIL4 are associated with better prognosis, while PIWIL1 and PIWIL3 involvement appears to be associated with carcinogenesis. We aimed to discover PIWIL3- and PIWIL4-modulated piRNAs and determine their potential mechanisms in pancreatic cancer and the clinical implications. PIWIL3 or PIWIL4 was downregulated in pancreatic cancer-derived cell lines or in a non-tumour cell line. Differentially expressed piRNAs were analysed by next generation sequencing of small RNA. Nine fresh-frozen samples from solid human pancreases (three healthy pancreases, three intraductal papillary mucinous neoplasms, and three early-stage pancreatic cancers) were included in the sequencing analysis. Two piRNAs associated with PIWIL3 (piR-168112 and piR-162725) were identified in the neoplastic cells; in untransformed samples, we identified one piRNA associated with PIWIL4 (pir-366845). After validation in pancreatic cancer-derived cell lines and one untransformed pancreatic cell line, these piRNAs were evaluated in plasma samples from healthy donors (n = 27) or patients with pancreatic cancer (n = 45). Interestingly, piR-162725 expression identified pancreatic cancer patients versus healthy donors in liquid biopsies. Moreover, the potential of the serum carbohydrate antigen 19-9 (CA19-9) biomarker to identify pancreatic cancer patients was greatly enhanced when combined with piR-162725 detection. The enhanced diagnostic potential for the early detection of pancreatic cancer in liquid biopsies of these new small non-coding RNAs will likely improve the prognosis and management of this deadly cancer.

A Novel circRNA hsa_circRNA_002178 as a Diagnostic Marker in Hepatocellular Carcinoma Enhances Cell Proliferation, Invasion, and Tumor Growth by Stabilizing SRSF1 Expression

Background. Previous research studies have shown that the elevation of circular RNA (circRNA), hsa_circRNA_002178, was associated with the poor prognosis of breast cancer and colorectal cancer, while its molecular mechanisms underlying the effects on hepatocellular carcinoma (HCC) are still elusive. Methods. The microarray dataset GSE97332 was obtained from the Gene Expression Omnibus (GEO) database and calculated by using the GEO2R tool to identify differentially expressed circRNAs. Differentially expressed hsa_circRNA_002178, in 7 HCC tissue samples and paracancerous tissues, as well as in HCC cell lines and normal hepatocytes, was checked by RT-qPCR. Cell proliferation, invasion, migration, and epithelial-to-mesenchymal transition (EMT)-related proteins were tested in hsa_circRNA_002178-overexpressed or hsa_circRNA_002178-knocked down HCC cells. Subsequently, we identified whether hsa_circRNA_002178 binds to serine- and arginine-rich splicing factor 1 (SRSF1) and then analyzed their function in regulating HCC cell behavior. The effect on HCC cell xenograft tumor growth was observed by the knockdown of hsa_circRNA_002178 in vivo. Results. GEO2R-based analysis displayed that hsa_circRNA_002178 was upregulated in HCC tissues. Overexpression or knockdown of hsa_circRNA_002178 encouraged or impeded HCC cell proliferation, migration, invasion, and EMT program. Mechanically, hsa_circRNA_002178 bound to SRSF1 3′-untranslated region (UTR) and stabilized its expression. SRSF1 weakening eliminated the effects of pcDNA-hsa_circRNA_002178 on cell malignant behavior. Finally, the knockdown of hsa_circRNA_002178 was confirmed to prevent xenograft tumor growth. Conclusions. hsa_circRNA_002178 overexpression encouraged the stability of SRSF1 mRNA expression, and it may serve as an upstream factor of SRSF1 for the diagnosis of HCC.

circ_0052184 Promotes Colorectal Cancer Progression via Targeting miR-604/HOXA9 Axis

Background

The mortality rate of colorectal cancer (CRC) ranks second. circRNAs are abnormal expression in some diseases, and their dysregulation is associated with cancer progression. Recent studies have shown that the malignant progression of colorectal cancer is inseparable from the abnormal expression of circRNAs.

Methods

First, the circ_0052184 expression in clinical tissue and cell samples was analyzed by qRT-PCR. Then, we constructed circ_0052184-silenced CRC cells and detected by qRT-PCR. Furthermore, the proliferation ability of cells was detected by colony formation assay. Cell migration ability was tested by wound healing assay and transwell assay. Cell invasion ability was detected by transwell assay.

Results

Expression of circ_0052184 was significantly increased in colorectal cancer cell lines and tissues. Silencing circ_0052184 affected the proliferation, migration, and invasion of colorectal cancer cells. miR-604 was targeted by circ_0052184. The downstream target of miR-604 was HOXA9, and silencing circ_0052184 inhibited HOXA9 expression. The existence of the circ_0052184/miR-604/HOXA9 regulatory network in colorectal cancer was validated. circ_0052184 promoted the occurrence and development of colorectal cancer by targeting the miR-604/HOXA9 axis.

Conclusions

Our study revealed that the molecular mechanism of circ_0052184 regulated the miR-604/HOXA9 axis, which might promote the malignant progression of colorectal cancer cells.

Circular RNAs as emerging players in cervical cancer tumorigenesis; A review to roles and biomarker potentials

Cervical cancer is the most lethal gynecological cancer among women worldwide. Most of the patients are diagnosed at the advanced stages due to late diagnosis and lack of accessible and valuable approaches for early detection of the disease. Circular RNAs (circRNAs) are a distinguishable class of non-coding RNAs with characteristic loop structures. Although their function has not been completely elucidated; however, recent evidence has suggested regulatory functions for circRNAs on gene expression controlling various biological functions like cell growth and apoptosis, development, embryogenesis, and pathogenesis of human diseases particularly cancers. Studies show the role of dysregulated circRNAs in biological processes including cell proliferation, migration, invasion, apoptosis, angiogenesis, and chemoresistance contributing to affect tumorigenesis in ovarian cancer cells, animal, and clinical studies. These effects can be defined as consistent with several tumorigenesis characteristics, which are defined as "hallmarks of cancer". Additionally, dysregulated circRNAs exhibit prognostic, and diagnostic potentials both in the prediction of prognosis in ovarian cancer patients, and also their discrimination from healthy individuals. Furthermore, targeting circRNAs has shown positive results in the suppression of malignant features of cancer cells, and also in overcoming chemoresistance. In this review, I have gathered the majority of studies evaluating the role of circRNAs in the development, and progression of cervical cancer, and also have discussed prognostic, diagnostic, and therapeutic potentials of circRNAs for clinical applications in cervical cancer patients.

Encoding gene RAB3B exists in linear chromosomal and circular extrachromosomal DNA and contributes to cisplatin resistance of hypopharyngeal squamous cell carcinoma via inducing autophagy

Cisplatin (DDP) resistance is an important factor that decreases the effect of chemotherapy, thus leading to local recurrence and lymph node metastasis of hypopharyngeal squamous cell carcinoma (HSCC). We aimed to explore the role and mechanism of extrachromosomal circular DNA (eccDNA) in the DDP resistance of HSCC. In our research, the HSCC cell line FaDu and the DDP-resistant cell line FaDu/DDP were used as subjects. eccDNA sequencing and whole transcriptome sequencing were conducted, followed by a combined analysis of the two sequencing profiles. Outward PCR, inward PCR and Sanger sequencing were used to verify sequences of the eccDNAs. Bioinformatics analysis based on TCGA/GEO was performed in addition to plasmid transfection, RNA interference, qRT-PCR and Western blot experiments to verify the expression level of RAB3B amplified from eccDNA. mRFP-GFP-LC3 adenoviral particle transfection and transmission electron microscopy were used to detect autophagic flux. Finally, we evaluated the role of RAB3B in FaDu/DDP cells and patient-derived organoids. Our results showed that we purified and sequenced more than 10 thousand eccDNAs from the two cell lines, and the size of the eccDNAs was distributed from 0.01 kb to 1000 kb. The combined analysis between eccDNA and transcript sequencing indicated that there were some highly expressed genes that were completely or partially transcribed from related sequences of eccDNAs and not from genome linear DNA. We further screened and verified the encoding gene RAB3B using full-length sequences that might be amplified from eccDNA [chr1^{circle 46219-52682 kb}]. Finally, we confirmed that RAB3B could promote DDP resistance in HSCC by inducing autophagy. The eccDNA might play significant roles in DDP resistance in HSCC by amplifying related functional genes. Further study is needed to explore the novel mechanisms of eccDNA in the drug resistance of HSCC.

MicroRNA-98-5p modulates cervical cancer progression via controlling PI3K/AKT pathway

To probe into the potential mechanism of microRNA (miR)-98-5p inhibiting the biological progress of cervical cancer (CC) cells via regulating PI3K/Akt pathway. Reverse transcription quantitative polymerase chain reaction was applied to detect miR-98-5p expression in CC tissues and cell lines; Cell counting kit-8 and Edu analysis were performed for checking cell proliferation, flow cytometry for cell apoptosis, transwell for cell invasion and migration, Western blot for proliferation-related proteins Ki67 and Proliferating cell nuclear antigen expression, apoptosis-related proteins Bcl-2 and Bax expression, epithelial-mesenchymal transition (EMT)-related proteins Snail, matrix metalloproteinase-3, E-cadherin and N-cadherin expression, as well as PI3K/Akt pathway-related proteins PTEN, PI3K as well as Akt expression levels, and the nude mouse tumor xenograft experiment was applied to verify in vivo. The result clarified, miR-98-5p was reduced in CC. Overexpression miR-98-5p could inhibit CC cell proliferation, invasion, migration and EMT, whereas promoted its apoptosis, but silencing miR-98-5p was opposite. Overexpression miR-98-5p could depress the activation of PI3K/Akt pathway in CC in vivo and in vitro. MiR-98-5p targeted CBX5. In short, miR-98-5p is able to be used as a potential target for treating CC in future research.

Identification of a novel circ_0018289/miR-183-5p/TMED5 regulatory network in cervical cancer development

Background

Circular RNAs (circRNAs) are increasingly implicated in regulating human carcinogenesis. Previous work showed the oncogenic activity of circ_0018289 in cervical cancer. However, the molecular basis underlying the modulation of circ_0018289 in cervical carcinogenesis is still not fully understood.

Methods

The levels of circ_0018289, microRNA (miR)-183-5p, and transmembrane p24 trafficking protein 5 (TMED5) were measured by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot assay. Ribonuclease (RNase) R and subcellular localization assays were used to characterize circ_0018289. Cell proliferation was detected by the Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2′-deoxyuridine (Edu) assays. Cell apoptosis and tube formation were assessed by flow cytometry and tube formation assays, respectively. A dual-luciferase reporter assay was performed to confirm the direct relationship between miR-183-5p and circ_0018289 or TMED5. The role of circ_0018289 in tumor growth was gauged by mouse xenograft experiments.

Results

Circ_0018289 was overexpressed in cervical cancer tissues and cells. Circ_0018289 silencing impeded cell proliferation, enhanced cell apoptosis, and suppressed angiogenesis in vitro, as well as diminished tumor growth in vivo. Mechanistically, circ_0018289 targeted and regulated miR-183-5p by binding to miR-183-5p, and circ_0018289 regulated cervical cancer development and angiogenesis partially through miR-183-5p. Moreover, TMED5 was directly targeted and inhibited by miR-183-5p through the perfect complementary sites in TMED5 3′UTR, and TMED5 knockdown phenocopied miR-183-5p overexpression in suppressing cervical cancer development and angiogenesis. Furthermore, circ_0018289 induced TMED5 expression by competitively binding to shared miR-183-5p.

Conclusion

Our observations identified the circ_0018289/miR-183-5p/TMED5 regulatory network as a novel molecular basis underlying the modulation of cervical carcinogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02350-y.

Circular RNA hsa_circ_0000511 Improves Epithelial Mesenchymal Transition of Cervical Cancer by Regulating hsa-mir-296-5p/HMGA1

As the second largest gynecological cancer, cervical cancer has been widely reported in recent years in which circular RNA is involved in the disease process. We earlier found that the expression of hsa_circ_0000511 in cervical cancer cells increased significantly, but its role in the process of cervical cancer is not clear. The purpose of this study is to explore its possible mechanisms in cervical cancer. Quantitative reverse transcription polymerase chain reaction (qRT-PCR), cell counting kit-8 assay, Transwell test, cell transfection, RNA pull-down assay and dual-luciferase reporter assay, and Western blot analysis were used to detect the expression and distribution of hsa_circ_0000511 in SiHa and HeLa cells, the ability of invasion and proliferation, and the modulated relationships between hsa_circ_0000511 and hsa-mir-296-5p, hsa-mir-296-5p, and HMGA1. hsa_circ_0000511 had the highest expression in SiHa and HeLa cells, and the expression in the cytoplasm was significantly higher than that in the nucleus, and its expression was not affected by RNase R. When hsa_circ_0000511 was silenced, its expression in SiHa and HeLa cells was significantly decreased; the proliferation, invasion, and migration abilities of the two kinds of cells were significantly enhanced; and the protein expression of E-cadherin was significantly upregulated, while the protein expression of N-cadherin was significantly downregulated. The expression of hsa-mir-296-5p was lower in SiHa and HeLa cells; however, its expression was increased when hsa_circ_0000511 was inhibited and decreased when hsa_circ_0000511 was overexpressed, so did the ability of proliferation, invasion, and migration and the protein expression of E-cadherin. Interestingly, the protein expression of HMGA1 also changed in these two cells when hsa-mir-296-5p was inhibited or overexpressed. Our results indicate that the upregulated hsa_circ_0000511 can inhibit the proliferation, invasion, and migration of SiHa and HeLa cells by regulating hsa-mir-296-5p/HMGA1, suggesting that the hsa_circ_0000511/hsa-mir-296-5p/HMGA1 pathway may be a potential target for the treatment of cervical cancer.