Circ_0061140 knockdown inhibits tumorigenesis and improves PTX sensitivity by regulating miR-136/CBX2 axis in ovarian cancer

Abstract Background Ovarian cancer is an aggressive tumor in women with high mortality. Paclitaxel (PTX) can be used for the chemotherapy of ovarian cancer. Here, the roles of circular_0061140 (circ_0061140) in PTX sensitivity and malignant progression of ovarian cancer are unveiled. Methods The expressions of circ_0061140, microRNA-136 (miR-136) and chromobox 2 (CBX2) mRNA were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Protein expression was determined by western blot. The half maximal inhibitory concentration (IC50) of PTX was determined by 3-(4,5-Dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell proliferation was investigated by cell counting kit-8 (CCK-8) and colony formation assays. Cell apoptosis was demonstrated by flow cytometry analysis. Cell migration and invasion were evaluated by transwell assay. The binding relationship between miR-136 and circ_0061140 or CBX2 was predicted by interactome or starbase online database, and identified by dual-luciferase reporter assay. The effects of circ_0061140 on tumor formation and PTX sensitivity in vivo were disclosed by tumor formation assay. Results Circ_0061140 and CBX2 expressions were upregulated, while miR-136 expression was downregulated in PTX-resistant tissues and cells compared with control groups. Circ_0061140 knockdown repressed cell proliferation, migration and invasion, and promoted cell apoptosis and PTX sensitivity; however, these effects were restrained by miR-136 RNAi. Additionally, circ_0061140 was a sponge of miR-136, and miR-136 bound to CBX2. Furthermore, circ_0061140 knockdown inhibited tumor formation and improved PTX sensitivity in vivo. Conclusions Circ_0061140 silencing repressed the progression and PTX resistance of ovarian cancer by downregulating CBX2 expression via sponging miR-136, which provided novel insight into studying the therapy of ovarian cancer with PTX.

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Doxorubicin inhibits osteosarcoma progression by regulating circ_0000006/miR-646/ BDNF axis

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-021-02782-y ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Abulimiti Amuti ◽

Dehu Liu ◽

Ayiguli Maimaiti ◽

Yao Yu ◽

Yalikun Yasen ◽

...

Keyword(s):

Cell Proliferation ◽

Protein Expression ◽

Tumor Growth ◽

Cell Apoptosis ◽

Tumor Formation ◽

Cell Counting ◽

Luciferase Reporter ◽

Migration And Invasion ◽

Control Groups

Abstract Background Osteosarcoma (OS) is the most common aggressive bone tumor in children and teenagers. Doxorubicin (DOX) is a chemotherapeutic drug for OS. This study aims to reveal the effects and underneath mechanism of DOX treatment in OS progression. Methods The expression of circular_0000006 (circ_0000006), microRNA-646 (miR-646) and brain-derived neurotrophic factor (BDNF) was detected by quantitative real-time polymerase chain reaction (qRT-PCR). BDNF protein expression was determined by western blot. Cell proliferation was illustrated by cell counting kit-8 (CCK-8) and cell colony formation assays. Cell migration and invasion were revealed by transwell migration and wound-healing assays and transwell invasion assay, respectively. Cell apoptosis was demonstrated by flow cytometry analysis. The binding relationship of miR-646 and circ_0000006 or BDNF was predicted by circRNA interactome and targetscan online database, respectively, and verified by dual-luciferase reporter assay. The effects of circ_0000006 knockdown on tumor growth in vivo were manifested by in vivo tumor formation assay. Results Circ_0000006 expression and the mRNA and protein levels of BDNF were dramatically upregulated, and miR-646 expression was effectively downregulated in OS tissues or cells compared with control groups. Circ_0000006 expression and BDNF protein expression were lower, and miR-646 expression was higher in DOX treatment groups than in control groups in OS cells. Circ_0000006 knockdown repressed cell proliferation, migration and invasion, whereas promoted cell apoptosis under DOX treatment in OS cells; however, these effects were attenuated by miR-646 inhibitor. Additionally, circ_0000006 sponged miR-646 to bind to BDNF. Circ_0000006 silencing suppressed tumor growth in vivo. Conclusion Circ_0000006 knockdown promoted DOX-mediated effects on OS development by miR-646/BDNF pathway, which provided a theoretical basis in treating OS with DOX.

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Sevoflurane inhibits malignant progression of colorectal cancer via hsa_circ_0000231-mediated miR-622

Journal of Biological Research-Thessaloniki ◽

10.1186/s40709-021-00145-6 ◽

2021 ◽

Vol 28 (1) ◽

Author(s):

Jingpeng Wang ◽

Shuyuan Li ◽

Gaofeng Zhang ◽

Huihua Han

Keyword(s):

Colorectal Cancer ◽

Cell Proliferation ◽

Cell Apoptosis ◽

Volatile Anesthetic ◽

Tumor Formation ◽

Luciferase Reporter ◽

Migration And Invasion ◽

Circular Rnas

Abstract Background Sevoflurane (Sev), a commonly used volatile anesthetic, has been reported to inhibit the process of colorectal cancer (CRC). Circular RNAs (circRNAs) are revealed to participate in the pathogenesis of CRC. This study aims to reveal the mechanism of hsa_circ_0000231 in Sev-mediated CRC progression. Methods The expression of hsa_circ_0000231 and microRNA-622 (miR-622) was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Protein level was determined by western blot analysis. Cell proliferation was investigated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), cell colony formation and DNA content quantitation assays. Cell apoptosis was detected by Annexin V-fluorescein isothiocyanate and propidium iodide double staining and caspase 3 activity assays. Cell migration and invasion were investigated by wound-healing and transwell invasion assays, respectively. The putative relationship between hsa_circ_0000231 and miR-622 was predicted by circular RNA Interactome online database, and identified by dual-luciferase reporter and RNA immunoprecipitation assays. The impacts of hsa_circ_0000231 on Sev-mediated tumor formation in vivo were presented by in vivo assay. Results Hsa_circ_0000231 expression was upregulated, while miR-622 was downregulated in CRC tissues and cells compared with control groups. Sev treatment decreased hsa_circ_0000231 expression, but increased miR-622 expression in CRC cells. Sev treatment suppressed cell proliferation, migration and invasion, and induced cell apoptosis. Hsa_circ_0000231 overexpression restored Sev-mediated CRC progression in vitro. Additionally, hsa_circ_0000231 acted as a sponge of miR-622, and miR-622 inhibitors reversed the impacts of hsa_circ_0000231 silencing on CRC process. Furthermore, Sev treatment inhibited tumor growth by regulating hsa_circ_0000231 in vivo. Conclusion Hsa_circ_0000231 attenuated Sev-aroused repression impacts on CRC development by sponging miR-622. This findings may provide an appropriate anesthetic protocol for CRC sufferers undergoing surgery.

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Circ-RNF121 regulates tumor progression and glucose metabolism by miR-1224-5p/FOXM1 axis in colorectal cancer

Cancer Cell International ◽

10.1186/s12935-021-02290-3 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Zhipeng Jiang ◽

Hao Hu ◽

Wenli Hu ◽

Zehui Hou ◽

Wei Liu ◽

...

Keyword(s):

Colorectal Cancer ◽

Cell Proliferation ◽

Cell Apoptosis ◽

Ring Finger ◽

Circular Rna ◽

Tumor Formation ◽

Luciferase Reporter ◽

Migration And Invasion ◽

Forkhead Box M1

Abstract Aim Previous studies have reported that circular RNA (circRNA) is associated with the pathogenesis of CRC. This study was designed to reveal the mechanism of circ-ring finger protein 121 (circ-RNF121) in colorectal cancer (CRC). Materials and methods The levels of circ-RNF121, microRNA-1224-5p (miR-1224-5p) and forkhead box M1 (FOXM1) were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Protein level was detected by western blot. Cell proliferation was analyzed by 3-(4,5-Dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and cell colony formation assays. Flow cytometry analysis was performed to investigate cell apoptosis. Cell migration and invasion were investigated by transwell and wound-healing assays. Cell glycolysis was detected using glucose, lactate and ADP/ATP ratio assay kits. The binding relationship between miR-1224-5p and circ-RNF121 or FOXM1 was predicted by starBase online database, and identified by dual-luciferase reporter assay. The impacts of circ-RNF121 silencing on tumor formation in vivo were disclosed by in vivo tumor formation assay. Key findings Circ-RNF121 and FOXM1 expression were dramatically upregulated, while miR-1224-5p expression was downregulated in CRC tissues or cells compared with control groups. Circ-RNF121 silencing repressed cell proliferation, migration, invasion and glycolysis but induced cell apoptosis in CRC, which were attenuated by miR-1224-5p inhibitor. Additionally, circ-RNF121 acted as a sponge of miR-1224-5p and miR-1224-5p bound to FOXM1. Circ-RNF121 silencing inhibited tumor growth in vivo. Furthermore, circ-RNF121 was secreted through being packaged into exosomes. Significance The finding provided a novel insight into studying circRNA-mediated CRC therapy.

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Circ_0082182 promotes oncogenesis and metastasis of colorectal cancer in vitro and in vivo by sponging miR-411 and miR-1205 to activate the Wnt/β-catenin pathway

World Journal of Surgical Oncology ◽

10.1186/s12957-021-02164-y ◽

2021 ◽

Vol 19 (1) ◽

Cited By ~ 1

Author(s):

Ruijie Liu ◽

Ping Deng ◽

Yonglian Zhang ◽

Yonglan Wang ◽

Cuiping Peng

Keyword(s):

Cell Cycle ◽

Cell Proliferation ◽

Cell Apoptosis ◽

Xenograft Model ◽

Cell Counting ◽

Luciferase Reporter ◽

Migration And Invasion ◽

Circular Rnas ◽

Mesenchymal Transition

Abstract Background Circular RNAs (circRNAs) are a class of endogenous single-strand RNA transcripts with crucial regulation in human cancers. The objective of this study is to investigate the role of circ_0082182 in CRC and its specific functional mechanism. Methods The quantitative real-time polymerase chain reaction (qRT-PCR) was performed to measure the levels of circ_0082182, microRNA-411 (miR-411) and microRNA-1205 (miR-1205). Cell proliferation was detected by Cell counting Kit-8 (CCK-8) and colony formation assays. Flow cytometry was used for determining cell cycle and cell apoptosis. Cell apoptosis was also assessed by caspase3 and caspase9 activities. Cell migration and invasion were examined using scratch assay and transwell assay. The interaction between circ_0082182 and miRNA was validated by the dual-luciferase reporter and biotinylated RNA pull-down assays. Wnt/β-catenin pathway and epithelial-mesenchymal transition (EMT)-associated proteins were quantified by Western blot. Xenograft model was established for the research of circ_0082182 in vivo. Results Circ_0082182 was upregulated in CRC and could predict the poor prognosis of CRC patients. Functionally, circ_0082182 promoted CRC cell proliferation, cell cycle progression, and metastasis while inhibited apoptosis. Subsequently, circ_0082182 was shown to act as the sponges of miR-411 and miR-1205. MiR-411 and miR-1205 were identified as tumor inhibitors in CRC. Furthermore, circ_0082182 promoted the CRC progression via sponging miR-411 and miR-1205. Moreover, circ_0082182 facilitated the Wnt/β-catenin pathway and EMT process by targeting miR-411 and miR-1205. In vivo, circ_0082182 accelerated the CRC tumorigenesis and EMT process by activating the Wnt/β-catenin pathway by downregulating the expression of miR-411 or miR-1205. Conclusion This study showed that circ_0082182 functioned as an oncogene in the developing process of CRC by sponging miR-411 or miR-1205 to activate the Wnt/β-catenin pathway. Circ_0082182 might be a molecular target in the diagnosis and treatment of CRC.

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miR-23b-3p Inhibits the Oncogenicity of Colon Adenocarcinoma by Directly Targeting NFE2L3

Journal of Oncology ◽

10.1155/2021/8493225 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Guohong Huang ◽

Yimei Yang ◽

Mengxin Lv ◽

Tian Huang ◽

Xiaoyan Zhan ◽

...

Keyword(s):

Cell Proliferation ◽

Cell Lines ◽

Cell Apoptosis ◽

Regulatory Mechanism ◽

Malignant Tumors ◽

Cell Counting ◽

Luciferase Reporter ◽

Migration And Invasion

Background and Aims. MicroR-23b-3p (miR-23b-3p) has been found to be abnormally expressed in a variety of malignant tumors and to play a role in tumor inhibition or promotion. However, the regulatory mechanism of miR-23b-3p in COAD remains unclear. The purpose of this study was to investigate the clinical significance of miR-23b-3p expression in COAD cells and to explore its role and regulatory mechanism in the growth of COAD. Materials and Methods. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure miR-23b-3p expression in COAD tissues and cell lines. After transfecting miR-23b-3p mimics into two human COAD cell lines (SW620 and LoVo), the cell counting kit-8 (CCK-8), colony formation, and 5-ethynyl-2′-deoxyuridine (EdU) assays were used to detect cell proliferation, the Transwell assay was used to measure cell migration and invasion capacity, and flow cytometry was used to evaluate cell apoptosis in vitro. In addition, a luciferase reporter assay was used to determine whether miR-23b-3p targets NFE2L3. The downstream regulatory mechanisms of miR-23b-3p action in COAD cells were also investigated. For in vivo tumorigenesis assay, COAD cells stably overexpressing miR-23b-3p were injected subcutaneously into the flank of nude mice to obtain tumors. Results. Significantly decreased expression of miR-23b-3p was detected in COAD tissues and cell lines. Exogenous miR-23b-3p expression inhibited cell proliferation, migration, and invasion and promoted cell apoptosis of COAD cells in vitro. Nuclear factor erythroid 2 like 3 (NFE2L3) was identified as a direct target gene of miR-23b-3p. In addition, reintroduction of NFE2L3 partially abolished the anticancer effects of miR-23b-3p on COAD cells. Furthermore, miR-23b-3p overexpression hindered the growth of COAD cells in vivo. Conclusion. miR-23b-3p inhibited the oncogenicity of COAD cells in vitro and in vivo by directly targeting NFE2L3, suggesting the importance of the miR-23b-3p/NFE2L3 pathway in the development of COAD.

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Circular RNA Circ_0013958 Functions as a Tumor Promoter in Ovarian Cancer by Regulating miR-637/PLXNB2 Axis

Frontiers in Genetics ◽

10.3389/fgene.2021.644451 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yanfei Liang ◽

Kaiyi Meng ◽

Rui Qiu

Keyword(s):

Ovarian Cancer ◽

Cell Proliferation ◽

Circular Rna ◽

Tumor Promoter ◽

Cell Counting ◽

Luciferase Reporter ◽

Migration And Invasion ◽

Circular Rnas ◽

Western Blot Assay

Background: Circular RNAs (circRNAs) have emerged as important regulators in diverse human malignancies, including ovarian cancer (OC). This study was performed to explore the function and regulatory mechanism underlying circ_0013958 in OC progression.Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot assay was applied to examine the expression of circ_0013958, microRNA-637 (miR-637), and Plexin B2 (PLXNB2). The target relationship between miR-637 and circ_0013958 or PLXNB2 was verified by dual-luciferase reporter assay or RNA immunoprecipitation (RIP) assay. Cell Counting Kit-8 (CCK-8) and colony formation assays were employed to detect cell viability and clonogenicity ability, respectively. Cell migration and invasion were analyzed by Transwell assay. Cell apoptosis was monitored by flow cytometry. The role of circ_0013958 in vivo was determined by xenograft tumor assay.Results: Circ_0013958 and PLXNB2 were upregulated, while miR-637 was downregulated in OC tissues and cells. Circ_0013958 acted as a sponge for miR-637 to regulate the expression of PLXNB2 in OC cells. The repression effects of circ_0013958 knockdown on cell proliferation, migration, invasion, and apoptosis in OC cells were partly attenuated by the miR-637 inhibitor. And miR-637 targeted PLXNB2 to suppress OC cell proliferation, migration, and invasion. Moreover, circ_0013958 silencing blocked OC tumor growth in vivo.Conclusion: Circ_0013958 knockdown impeded OC development through modulating the miR-637/PLXNB2 axis, highlighting a therapeutic target for OC.

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Circ_0055625 knockdown inhibits tumorigenesis and improves radiosensitivity by regulating miR-338-3p/MSI1 axis in colon cancer

World Journal of Surgical Oncology ◽

10.1186/s12957-021-02234-1 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Chao Gao ◽

Yi Zhang ◽

Yanming Tian ◽

Chun Han ◽

Lan Wang ◽

...

Keyword(s):

Colon Cancer ◽

Cell Proliferation ◽

Colony Formation ◽

Radiation Treatment ◽

Tumor Formation ◽

Cell Counting ◽

Luciferase Reporter ◽

Migration And Invasion ◽

Survival Fraction

Abstract Background Radiotherapy is a main therapeutic method for cancers, including colon cancer. In the current study, we aim to explore the effects of circular RNA (circRNA) circ_0055625 in the progression and radiosensitivity of colon cancer and the underlying mechanism. Methods The expression of circ_0055625 and musashi homolog 1 (MSI1) mRNA was detected by quantitative real-time polymerase chain reaction (qRT-PCR). MSI1 protein expression was determined by Western blot. Cell proliferation was assessed by cell counting kit-8 (CCK-8) and colony formation assays. Cell survival fraction, apoptosis, and invasion were investigated by colony formation assay, flow cytometry analysis, and transwell invasion assay, respectively. Cell migration was detected by wound-healing and transwell migration assays. The binding relationship between microRNA-338-3p (miR-338-3p) and circ_0055625 or MSI1 was predicted by online databases and identified by Dual-Luciferase Reporter Assay. The effects of circ_0055625 silencing on the tumor formation and radiosensitivity of colon cancer in vivo were explored by in vivo tumor formation assay. Results Circ_0055625 and MSI1 were upregulated in colon cancer tissues and cells relative to control groups. Radiation treatment apparently increased the expression of circ_0055625 and MSI1 in colon cancer cells. Circ_0055625 knockdown or MSI1 silencing repressed cell proliferation, migration, and invasion and promoted cell apoptosis and radiosensitivity in colon cancer. Also, circ_0055625 silencing-mediated effects were attenuated by MSI1 overexpression. Additionally, circ_0055625 silencing reduced MSI1 expression, which could be attenuated by miR-338-3p inhibitor. Mechanically, circ_0055625 acted as a sponge for miR-338-3p to regulate MSI1. Furthermore, circ_0055625 knockdown hindered tumor growth and improved radiosensitivity in vivo. Conclusion Circ_0055625 repression inhibited the progression and radioresistance of colon cancer by downregulating MSI1 through sponging miR-338-3p. This result might provide a theoretical basis for improving the therapy of colon cancer with radiation.

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lncRNA TUG1-Mediated Mir-142-3p Downregulation Contributes to Metastasis and the Epithelial-to-Mesenchymal Transition of Hepatocellular Carcinoma by Targeting ZEB1

Cellular Physiology and Biochemistry ◽

10.1159/000492517 ◽

2018 ◽

Vol 48 (5) ◽

pp. 1928-1941 ◽

Cited By ~ 27

Author(s):

Chuan He ◽

Zhigang Liu ◽

Li Jin ◽

Fang Zhang ◽

Xinhao Peng ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Cell Proliferation ◽

Cell Migration ◽

Noncoding Rna ◽

Epithelial Mesenchymal Transition ◽

Tumor Formation ◽

Luciferase Reporter ◽

Migration And Invasion ◽

Mesenchymal Transition

Background/Aims: MicroRNA-142-3p (miR-142-3p) is dysregulated in many malignancies and may function as a tumor suppressor or oncogene in tumorigenesis and tumor development. However, few studies have investigated the clinical significance and biological function of miR-142-3p in hepatocellular carcinoma (HCC). Methods: The expression levels of taurine upregulated gene 1 (TUG1), miR-142-3p, and zinc finger E-box-binding homeobox 1 (ZEB1) were evaluated in HCC tissues and cell lines by quantitative real-time PCR. MTT and colony formation assays were used to detect cell proliferation ability, transwell assays were used to assess cell migration and invasion, and luciferase reporter assays were used to examine the interaction between the long noncoding RNA TUG1 and miR-142-3p. Tumor formation was evaluated through in vivo experiments. Results: miR-142-3p was significantly downregulated in HCC tissues, but TUG1 was upregulated in HCC tissues. Knockdown of TUG1 and upregulation of miR-142-3p inhibited cell proliferation, cell migration, cell invasion, and the epithelial-mesenchymal transition (EMT). miR-142-3p was found to be a prognostic factor of HCC, and the mechanism by which TUG1 upregulated ZEB1 was via direct binding to miR-142-3p. In vivo assays showed that TUG1 knockdown suppressed cell proliferation and the EMT in nude mice. Conclusion: The results of this study suggest that the TUG1/miR-142-3p/ ZEB1 axis contributes to the formation of malignant behaviors in HCC.

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Circ_0015756 promotes the progression of ovarian cancer by regulating miR-942-5p/CUL4B pathway

Cancer Cell International ◽

10.1186/s12935-020-01666-1 ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Zhenhua Du ◽

Lei Wang ◽

Yu Xia

Keyword(s):

Ovarian Cancer ◽

Tumor Growth ◽

Western Blot ◽

Gynecologic Cancer ◽

Cell Counting ◽

Luciferase Reporter ◽

Migration And Invasion ◽

Circular Rnas ◽

Western Blot Assay

Abstract Background Ovarian cancer (OC) is the gynecologic cancer with the highest mortality. Circular RNAs (circRNAs) play a vital role in the development and progression of cancer. This study aimed to explore the potential role of circ_0015756 in OC and its molecular mechanism. Methods The levels of circ_0015756, microRNA-942-5p (miR-942-5p) and Cullin 4B (CUL4B) were determined by quantitative real-time PCR (qRT-PCR) or Western blot assay. Cell proliferation, apoptosis, migration and invasion were assessed by Cell Counting Kit-8 (CCK-8), colony formation assay, flow cytometry and transwell assay. The levels of proliferation-related and metastasis-related proteins were measured by Western blot assay. The relationship between miR-942-5p and circ_0015756 or CUL4B was verified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay. Xenograft assay was used to analyze tumor growth in vivo. Results Circ_0015756 and CUL4B levels were increased, while miR-942-5p level was decreased in OC tissues and cells. Depletion of circ_0015756 suppressed proliferation, migration and invasion and promoted apoptosis in OC cells. Down-regulation of circ_0015756 hindered OC cell progression via modulating miR-942-5p. Also, up-regulation of miR-942-5p impeded OC cell development by targeting CUL4B. Mechanistically, circ_0015756 up-regulated CUL4B via sponging miR-942-5p. Moreover, circ_0015756 silencing inhibited tumor growth in vivo. Conclusion Knockdown of circ_0015756 suppressed OC progression via regulating miR-942-5p/CUL4B axis, suggesting that circ_0015756 might be a potential therapeutic target for ovarian cancer.

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CircFOXM1 promotes the proliferation, migration, invasion, and glutaminolysis of glioblastoma by regulating the miR-577/E2F5 axis

Bosnian Journal of Basic Medical Sciences ◽

10.17305/bjbms.2021.6028 ◽

2021 ◽

Author(s):

Xuhui Fan ◽

Meng Liu ◽

Li Fei ◽

Zhihui Huang ◽

Yufeng Yan

Keyword(s):

Cell Proliferation ◽

Xenograft Model ◽

Circular Rna ◽

Suppressive Effect ◽

Cell Counting ◽

Luciferase Reporter ◽

Migration And Invasion ◽

In Vivo Experiments

Circular RNA (circRNA) is a key regulator of tumor progression. However, the role of circFOXM1 in glioblastoma (GBM) progression is unclear. The aim of this study was to investigate the role of circFOXM1 in GBM progression. The expression levels of circFOXM1, miR-577 and E2F transcription factor 5 (E2F5) were examined by real-time quantitative PCR. Cell counting kit 8 assay, EdU staining and transwell assay were used to detect cell proliferation, migration, and invasion. The levels of glutamine, glutamate and α-ketoglutarate were determined to evaluate the glutaminolysis ability of cells. Protein expression was tested by western blot analysis. Dual-luciferase reporter assay, RNA pull-down assay and RNA immunoprecipitation assay were employed to verify the interaction between miR-577 and circFOXM1 or E2F5. Mice xenograft model for GBM was constructed to perform in vivo experiments. Our results showed that circFOXM1 was highly expressed in GBM tumor tissues and cells. Silencing of circFOXM1 inhibited GBM cell proliferation, migration, invasion, glutaminolysis, as well as tumor growth. MiR-577 could be sponged by circFOXM1, and its inhibitor could reverse the suppressive effect of circFOXM1 downregulation on GBM progression. E2F5 was a target of miR-577, and the effect of its knockdown on GBM progression was consistent with that of circFOXM1 silencing. CircFOXM1 positively regulated E2F5 expression, while miR-577 negatively regulated E2F5 expression. In conclusion, our data confirmed that circFOXM1 could serve as a sponge of miR-577 to enhance the progression of GBM by targeting E2F5, which revealed that circFOXM1 might be a biomarker for GBM treatment.

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