circEVI5 acts as a miR-4793-3p sponge to suppress the proliferation of gastric cancer

AbstractCircular RNAs (circRNAs) are a novel class of endogenous noncoding RNAs (ncRNAs) with a covalently closed loop structure. Accumulating evidence shows that circRNAs play vital roles in the growth, metastasis, treatment and prognosis of various cancers. However, the detailed functions and underlying mechanisms of circEVI5 (hsa_circ_0013162) in gastric cancer (GC) remain undocumented. In this study, the expression levels and prognostic value of circEVI5 were validated in GC tissue samples by using qRT-PCR. circEVI5 was significantly downregulated in GC tissues and cells, and low circEVI5 expression was correlated with poor prognosis. Next, in vitro CCK-8 assay, EdU incorporation assay, PI staining cell cycle assay, and in vivo xenograft mouse models were conducted to assess the functions of circEVI5. Gain of function experiments indicated that circEVI5 could inhibit GC cell proliferation and retard the cell cycle. Moreover, bioinformatics prediction showed that circEVI5 binds to miR-4793-3p, while FOXO1 may be a target of miR-4793-3p. Pull-down assays, RNA immunoprecipitation (RIP) assays, luciferase assays, and western blot were used to confirm the interactions between circEVI5, miR-4793-3p, and FOXO1. Functional assays demonstrated that circEVI5 suppressed the proliferation of GC by sponging miR-4793-3p and increasing FOXO1 expression levels. In conclusion, our study demonstrated that circEVI5 can bind miR-4793-3p as a ceRNA to eliminate the negative regulation of FOXO1, therefore suppressing GC proliferation.

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KCNQ1OT1 accelerates gastric cancer progression via miR-4319/DRAM2 axis

International Journal of Immunopathology and Pharmacology ◽

10.1177/2058738420954598 ◽

2020 ◽

Vol 34 ◽

pp. 205873842095459

Author(s):

Jijun Wang ◽

Fan Wu ◽

Yaoyao Li ◽

Lei Pang ◽

Xiaohong Wang ◽

...

Keyword(s):

Gastric Cancer ◽

Cell Growth ◽

Cancer Progression ◽

Promising Target ◽

Tumor Tissues ◽

Rna Immunoprecipitation ◽

Opposite Strand ◽

Underlying Mechanisms

Introduction: This work was to explore the connection of KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) and microRNA-4319 (miR-4319), and to investigate the associated underlying mechanisms in gastric cancer (GC) progression. Methods: Quantitative real-time PCR was performed to measure KCNQ1OT1, miR-4319 and DNA-damage regulated autophagy modulator 2 (DRAM2) expression levels in GC cells. Moreover, expression level of KCNQ1OT1 and DRAM2 in GC tissues was analyzed at ENCORI website ( http://starbase.sysu.edu.cn/index.php ). Cell proliferation, colony formation assay and flow cytometry assays were performed to analyze effects of KCNQ1OT1, miR-4319 and DRAM2 on cell growth and death. Dual-luciferase activity reporter assay and RNA immunoprecipitation assay was conducted to verify the interactions of KCNQ1OT1 or DRAM2 and miR-4319. Results and Conclusion: We found KCNQ1OT1 level was increased in tumor tissues and cells. Force the expression of KCNQ1OT1 promotes, while knockdown KCNQ1OT1 inhibits GC cell growth. Further studies indicated miR-4319 functioned as a bridge between KCNQ1OT1 and DRAM2. Finally, we showed KCNQ1OT1/miR-4319/DRAM2 axis regulates GC cell growth in vitro and in vivo. lncRNA KCNQ1OT1 promotes GC progression by sponging miR-4319 to upregulate DRAM2, indicating KCNQ1OT1 might be a promising target for GC treatment.

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circCUL2 regulates gastric cancer malignant transformation and cisplatin resistance by modulating autophagy activation via miR-142-3p/ROCK2

Molecular Cancer ◽

10.1186/s12943-020-01270-x ◽

2020 ◽

Vol 19 (1) ◽

Author(s):

Lei Peng ◽

Huaiming Sang ◽

Shuchun Wei ◽

Yuanyuan Li ◽

Duochen Jin ◽

...

Keyword(s):

Gastric Cancer ◽

Malignant Transformation ◽

Cell Lines ◽

Circular Rnas ◽

Transmission Electron ◽

Rna Immunoprecipitation ◽

Cisplatin Sensitivity ◽

Cellular Apoptosis

Abstract Background Circular RNAs (circRNAs) are a class of noncoding RNAs (ncRNAs) and can modulate gene expression by binding to miRNAs; further, circRNAs have been shown to participate in several pathological processes. However, the expression and biological function of circCUL2 in gastric cancer (GC) remains largely unknown. Methods circRNA microarrays and quantitative real-time PCR (qRT-PCR) were used to identify differentially expressed circRNAs in GC tissues and cell lines. circCUL2 knockdown and overexpression were performed to indicate the functional role of circCUL2 in vitro and in vivo. The expression and regulation of circCUL2, miR-142-3p and ROCK2 were evaluated using fluorescence in situ hybridization (FISH), dual-luciferase assays, RNA pull-down assays, RNA immunoprecipitation (RIP) and rescue experiments. Furthermore, the regulation of cisplatin sensitivity and autophagy by circCUL2/miR-142-3p/ROCK2 was demonstrated by cellular apoptosis assays, western blot, immunofluorescence and transmission electron microscopy analyses. Results The level of circCUL2, which is stable and cytoplasmically localized, was significantly reduced in GC tissues and cells. Overexpressed circCUL2 inhibited malignant transformation in vitro and tumorigenicity in vivo. In the AGS and SGC-7901 cell lines, circCUL2 sponged miR-142-3p to regulate ROCK2, thus modulating tumor progression. Furthermore, in the AGS/DDP and SGC-7901/DDP cell lines, circCUL2 regulated cisplatin sensitivity through miR-142-3p/ROCK2-mediated autophagy activation. Conclusion circCUL2 may function as a tumor suppressor and regulator of cisplatin sensitivity through miR-142-3p/ROCK2-mediated autophagy activation, which could be a key mechanism and therapeutic target for GC.

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MiR-375 reduces the stemness of gastric cancer cells through triggering ferroptosis

Stem Cell Research & Therapy ◽

10.1186/s13287-021-02394-7 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Haiwei Ni ◽

Hai Qin ◽

Cheng Sun ◽

Yichen Liu ◽

Guojing Ruan ◽

...

Keyword(s):

Gastric Cancer ◽

Ectopic Expression ◽

Luciferase Reporter ◽

Gastric Cancer Cells ◽

Stress Markers ◽

In Vivo Experiments ◽

Rna Immunoprecipitation ◽

Underlying Mechanisms

Abstract Background Gastric cancer stem cells (CSCs) are the main causes of metastasis and drug resistance. We previously indicated that miR-375 can inhibit Helicobacter pylori-induced gastric carcinogenesis; here, we aim to explore the effects and mechanisms of miR-375 on gastric cancer (GC) cell stemness. Methods Lentivirus infection was used to construct GC cells with ectopic expression of miR-375. In vitro and in vivo experiments, including analysis of tumor spheroid formation, CD44+ sub-population with stemness, stemness marker expression, and tumor-initiating ability, were performed to evaluate the effects of miR-375 on the stemness of GC cells. Furthermore, microarray and bioinformatics analysis were performed to search the potential targets of miR-375 in GC cells. Luciferase reporter, RNA immunoprecipitation, and RNA-FISH assays were carried out to verify the targeting of miR-375. Subsequently, combined with tissue microarray analysis, erastin-resistant GC cells, transmission electron microscopy, a series of agonists and oxidative stress markers, the underlying mechanisms contributing to miR-375-mediated effects were explored. Results MiR-375 reduced the stemness of GC cells in vitro and in vivo. Mechanistically, SLC7A11 was identified as a direct target of miR-375 and miR-375 attenuated the stemness of GC cells mainly through triggering SLC7A11-dependent ferroptosis. Conclusion MiR-375 can trigger the ferroptosis through targeting SLC7A11, which is essential for miR-375-mediated inhibition on GC cell stemness. These results suggest that the miR-375/SLC7A11 regulatory axis could serve as a potential target to provoke the ferroptosis and thus attenuate the stemness of GC cells.

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CircFAM13B promotes the proliferation of hepatocellular carcinoma by sponging miR-212, upregulating E2F5 expression and activating the P53 pathway

Cancer Cell International ◽

10.1186/s12935-021-02120-6 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Ying Xie ◽

Xiaofeng Hang ◽

Wensheng Xu ◽

Jing Gu ◽

Yuanjing Zhang ◽

...

Keyword(s):

Gene Expression ◽

Hepatocellular Carcinoma ◽

Gene Expression Omnibus ◽

Differentially Expressed ◽

In Vivo Studies ◽

Circular Rnas ◽

Novel Target ◽

Underlying Mechanisms

Abstract Background Most of the biological functions of circular RNAs (circRNAs) and the potential underlying mechanisms in hepatocellular carcinoma (HCC) have not yet been discovered. Methods In this study, using circRNA expression data from HCC tumor tissues and adjacent tissues from the Gene Expression Omnibus database, we identified out differentially expressed circRNAs and verified them by qRT-PCT. Functional experiments were performed to evaluate the effects of circFAM13B in HCC in vitro and in vivo. Results We found that circFAM13B was the most significantly differentially expressed circRNA in HCC tissue. Subsequently, in vitro and in vivo studies also demonstrated that circFAM13B promoted the proliferation of HCC. Further studies revealed that circFAM13B, a sponge of miR-212, is involved in the regulation of E2F5 gene expression by competitively binding to miR-212, inhibits the activation of the P53 signalling pathway, and promotes the proliferation of HCC cells. Conclusions Our findings revealed the mechanism underlying the regulatory role played by circFAM13B, miR-212 and E2F5 in HCC. This study provides a new theoretical basis and novel target for the clinical prevention and treatment of HCC.

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Novel Identified Circular Transcript of RCAN2, circ-RCAN2, Shows Deviated Expression Pattern in Pig Reperfused Infarcted Myocardium and Hypoxic Porcine Cardiac Progenitor Cells In Vitro

International Journal of Molecular Sciences ◽

10.3390/ijms22031390 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1390

Author(s):

Julia Mester-Tonczar ◽

Patrick Einzinger ◽

Johannes Winkler ◽

Nina Kastner ◽

Andreas Spannbauer ◽

...

Keyword(s):

Myocardial Infarction ◽

Progenitor Cells ◽

Regulatory Networks ◽

Circular Rnas ◽

Cardiac Progenitor Cells ◽

Tissue Samples ◽

Healthy Myocardium ◽

Acute Mi

Circular RNAs (circRNAs) are crucial in gene regulatory networks and disease development, yet circRNA expression in myocardial infarction (MI) is poorly understood. Here, we harvested myocardium samples from domestic pigs 3 days after closed-chest reperfused MI or sham surgery. Cardiac circRNAs were identified by RNA-sequencing of rRNA-depleted RNA from infarcted and healthy myocardium tissue samples. Bioinformatics analysis was performed using the CIRIfull and KNIFE algorithms, and circRNAs identified with both algorithms were subjected to differential expression (DE) analysis and validation by qPCR. Circ-RCAN2 and circ-C12orf29 expressions were significantly downregulated in infarcted tissue compared to healthy pig heart. Sanger sequencing was performed to identify the backsplice junctions of circular transcripts. Finally, we compared the expressions of circ-C12orf29 and circ-RCAN2 between porcine cardiac progenitor cells (pCPCs) that were incubated in a hypoxia chamber for different time periods versus normoxic pCPCs. Circ-C12orf29 did not show significant DE in vitro, whereas circ-RCAN2 exhibited significant ischemia-time-dependent upregulation in hypoxic pCPCs. Overall, our results revealed novel cardiac circRNAs with DE patterns in pCPCs, and in infarcted and healthy myocardium. Circ-RCAN2 exhibited differential regulation by myocardial infarction in vivo and by hypoxia in vitro. These results will improve our understanding of circRNA regulation during acute MI.

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Anti-glioma Efficacy and Mechanism of Action of Tripolinolate A from Tripolium pannonicum

Planta Medica ◽

10.1055/s-0044-101038 ◽

2018 ◽

Vol 84 (11) ◽

pp. 786-794

Author(s):

Weiyun Chai ◽

Lu Chen ◽

Xiao-Yuan Lian ◽

Zhizhen Zhang

Keyword(s):

Cell Cycle ◽

Transcription Factors ◽

Glioma Cells ◽

Inhibitory Effect ◽

Cell Cycle Regulators ◽

Expression Levels ◽

Multiple Tumor ◽

Glioma Growth

AbstractTripolinolate A as a new bioactive phenolic ester was previously isolated from a halophyte of Tripolium pannonicum. However, the in vitro and in vivo anti-glioma effects and mechanism of tripolinolate A have not been investigated. This study has demonstrated that (1) tripolinolate A inhibited the proliferation of different glioma cells with IC50 values of 7.97 to 14.02 µM and had a significant inhibitory effect on the glioma growth in U87MG xenograft nude mice, (2) tripolinolate A induced apoptosis in glioma cells by downregulating the expressions of antiapoptotic proteins and arrested glioma cell cycle at the G2/M phase by reducing the expression levels of cell cycle regulators, and (3) tripolinolate A also remarkably reduced the expression levels of several glioma metabolic enzymes and transcription factors. All data together suggested that tripolinolate A had significant in vitro and in vivo anti-glioma effects and the regulation of multiple tumor-related regulators and transcription factors might be responsible for the activities of tripolinolate A against glioma.

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Circular RNA CDR1as Inhibits the Metastasis of Gastric Cancer through Targeting miR-876-5p/GNG7 Axis

Gastroenterology Research and Practice ◽

10.1155/2021/5583029 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Jiajia Jiang ◽

Rong Li ◽

Junyi Wang ◽

Jie Hou ◽

Hui Qian ◽

...

Keyword(s):

Gastric Cancer ◽

Epithelial Mesenchymal Transition ◽

Circular Rna ◽

Luciferase Reporter ◽

Migration And Invasion ◽

Luciferase Reporter Gene ◽

Mesenchymal Transition ◽

Underlying Mechanisms

Circular RNA CDR1as has been demonstrated to participate in various cancer progressions as miRNA sponges. The exact underlying mechanisms of CDR1as on gastric cancer (GC) metastasis remain unknown. Here, we found that CDR1as knockdown facilitated GC cell migration and invasion while its overexpression inhibited the migration and invasion abilities of GC cells in vitro and in vivo. Moreover, epithelial-mesenchymal transition- (EMT-) associated proteins and MMP2 and MMP9 were downregulated by CDR1as. Bioinformatics analysis combined with dual-luciferase reporter gene assays, western blot, RT-qPCR analysis, and functional rescue experiments demonstrated that CDR1as served as a miR-876-5p sponge and upregulated the target gene GNG7 expression to suppress GC metastasis. In summary, our findings indicate that CDR1as suppresses GC metastasis through the CDR1as/miR-876-5p/GNG7 axis.

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Menadione reduces CDC25B expression and promotes tumor shrinkage in gastric cancer

Therapeutic Advances in Gastroenterology ◽

10.1177/1756284819895435 ◽

2020 ◽

Vol 13 ◽

pp. 175628481989543

Author(s):

Amanda Braga Bona ◽

Danielle Queiroz Calcagno ◽

Helem Ferreira Ribeiro ◽

José Augusto Pereira Carneiro Muniz ◽

Giovanny Rebouças Pinto ◽

...

Keyword(s):

Gastric Cancer ◽

Cell Cycle ◽

Cell Cycle Arrest ◽

Cell Lines ◽

Specific Inhibitor ◽

Gastric Carcinogenesis ◽

In Vivo Experiments ◽

Cycle Arrest

Background: Gastric cancer is one of the most incident types of cancer worldwide and presents high mortality rates and poor prognosis. MYC oncogene overexpression is a key event in gastric carcinogenesis and it is known that its protein positively regulates CDC25B expression which, in turn, plays an essential role in the cell division cycle progression. Menadione is a synthetic form of vitamin K that acts as a specific inhibitor of the CDC25 family of phosphatases. Methods: To better understand the menadione mechanism of action in gastric cancer, we evaluated its molecular and cellular effects in cell lines and in Sapajus apella, nonhuman primates from the new world which had gastric carcinogenesis induced by N-Methyl-N-nitrosourea. We tested CDC25B expression by western blot and RT-qPCR. In-vitro assays include proliferation, migration, invasion and flow cytometry to analyze cell cycle arrest. In in-vivo experiments, in addition to the expression analyses, we followed the preneoplastic lesions and the tumor progression by ultrasonography, endoscopy, biopsies, histopathology and immunohistochemistry. Results: Our tests demonstrated menadione reducing CDC25B expression in vivo and in vitro. It was able to reduce migration, invasion and proliferation rates, and induce cell cycle arrest in gastric cancer cell lines. Moreover, our in-vivo experiments demonstrated menadione inhibiting tumor development and progression. Conclusions: We suggest this compound may be an important ally of chemotherapeutics in the treatment of gastric cancer. In addition, CDC25B has proven to be an effective target for investigation and development of new therapeutic strategies for this malignancy.

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Epigenetic silencing of CDKN1A and CDKN2B by SNHG1 promotes the cell cycle, migration and epithelial-mesenchymal transition progression of hepatocellular carcinoma

Cell Death and Disease ◽

10.1038/s41419-020-03031-6 ◽

2020 ◽

Vol 11 (10) ◽

Author(s):

Bei Li ◽

Ang Li ◽

Zhen You ◽

Jingchang Xu ◽

Sha Zhu

Keyword(s):

Hepatocellular Carcinoma ◽

Cell Cycle ◽

Epithelial Mesenchymal Transition ◽

Critical Role ◽

Luciferase Assay ◽

Bioinformatics Analyses ◽

Mesenchymal Transition ◽

Rna Immunoprecipitation

Abstract Enhanced SNHG1 (small nucleolar RNA host gene 1) expression has been found to play a critical role in the initiation and progression of hepatocellular carcinoma (HCC) with its detailed mechanism largely unknown. In this study, we show that SNHG1 promotes the HCC progression through epigenetically silencing CDKN1A and CDKN2B in the nucleus, and competing with CDK4 mRNA for binding miR-140-5p in the cytoplasm. Using bioinformatics analyses, we found hepatocarcinogenesis is particularly associated with dysregulated expression of SNHG1 and activation of the cell cycle pathway. SNHG1 was upregulated in HCC tissues and cells, and its knockdown significantly inhibited HCC cell cycle, growth, metastasis, and epithelial–mesenchymal transition (EMT) both in vitro and in vivo. Chromatin immunoprecipitation and RNA immunoprecipitation assays demonstrate that SNHG1 inhibit the transcription of CDKN1A and CDKN2B through enhancing EZH2 mediated-H3K27me3 in the promoter of CDKN1A and CDKN2B, thus resulting in the de-repression of the cell cycle. Dual-luciferase assay and RNA pulldown revealed that SNHG1 promotes the expression of CDK4 by competitively binding to miR-140-5p. In conclusion, we propose that SNHG1 formed a regulatory network to confer an oncogenic function in HCC and SNHG1 may serve as a potential target for HCC diagnosis and treatment.

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CDK4/6 inhibitors: a novel strategy for tumor radiosensitization

Journal of Experimental & Clinical Cancer Research ◽

10.1186/s13046-020-01693-w ◽

2020 ◽

Vol 39 (1) ◽

Author(s):

Yilan Yang ◽

Jurui Luo ◽

Xingxing Chen ◽

Zhaozhi Yang ◽

Xin Mei ◽

...

Keyword(s):

Cell Cycle ◽

Clinical Studies ◽

Cell Cycle Progression ◽

Combined Therapy ◽

Small Sample ◽

Combination Strategies ◽

Novel Strategy ◽

Underlying Mechanisms

Abstract Recently, the focus of enhancing tumor radiosensitivity has shifted from chemotherapeutics to targeted therapies. Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors are a novel class of selective cell cycle therapeutics that target the cyclin D-CDK4/6 complex and induce G1 phase arrest. These agents have demonstrated favorable effects when used as monotherapy or combined with endocrine therapy and targeted inhibitors, stimulating further explorations of other combination strategies. Multiple preclinical studies have indicated that CDK4/6 inhibitors exhibit a synergistic effect with radiotherapy both in vitro and in vivo. The principal mechanisms of radiosensitization effects include inhibition of DNA damage repair, enhancement of apoptosis, and blockade of cell cycle progression, which provide the rationale for clinical use. CDK4/6 inhibitors also induce cellular senescence and promote anti-tumor immunity, which might represent potential mechanisms for radiosensitization. Several small sample clinical studies have preliminarily indicated that the combination of CDK4/6 inhibitors and radiotherapy exhibited well-tolerated toxicity and promising efficacy. However, most clinical trials in combined therapy remain in the recruitment stage. Further work is required to seek optimal radiotherapy-drug combinations. In this review, we describe the effects and underlying mechanisms of CDK4/6 inhibitors as a radiosensitizer and discuss previous clinical studies to evaluate the prospects and challenges of this combination.

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