Circ_0026579 alleviates LPS-induced WI-38 cells inflammation injury in infantile pneumonia

Circular RNA (circRNA) represents an important regulator in infantile pneumonia progression. To clarify the role of circ_0026579 in this disease, LPS was used to treat WI-38 cells to mimic inflammation injury. The levels of inflammatory factors were determined by ELISA assay. Cell proliferation and apoptosis were measured by MTT assay, EdU staining and flow cytometry. The protein levels of cyclinD1, cleaved-caspase-3 and insulin-like growth factor 2 (IGF2) were examined using Western blot analysis. Cell oxidative stress was assessed by detecting MDA level and SOD activity. The expression of circ_0026579, miR-24-3p and IGF2 were analyzed using quantitative real-time PCR, and the interaction between miR-24-3p and circ_0026579 or IGF2 was confirmed by dual-luciferase reporter assay and RIP assay. LPS induced inflammation in WI-38 cells. Circ_0026579 expression was promoted in LPS-induced WI-38 cells, and its knockdown alleviated LPS-induced WI-38 cells inflammation. MiR-24-3p was sponged by circ_0026579, and its expression was reduced by LPS. MiR-24-3p inhibitor reversed the regulation of circ_0026579 knockdown on LPS-induced WI-38 cells inflammation. IGF2 was targeted by miR-24-3p, and its expression could be enhanced by LPS. MiR-24-3p relieved the inflammation of WI-38 cells which could be abolished by IGF2 overexpression. Circ_0026579 positively regulated IGF2 expression through sponging miR-24-3p. Circ_0026579 knockdown alleviated LPS-induced WI-38 cells inflammation by miR-24-3p/IGF2 axis, suggesting that circ_0026579 might contribute to infantile pneumonia progression.     

Circ_0061012 contributes to IL-22-induced proliferation,migration and invasion in keratinocytes through miR-194-5p/GAB1 axis in psoriasis

Psoriasis is a chronic inflammation-associated skin disorder featured by excessive proliferation and abnormal differentiation of keratinocytes. Here, we intended to investigate the role of circular RNA 0061012 (circ_0061012) in psoriasis progression. The expression of circ_0061012, SLMO2-ATP5E readthrough (SLMO2-ATP5E) messenger RNA (mRNA), microRNA-194-5p (miR-194-5p) and GRB2 associated binding protein 1 (GAB1) mRNA was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation and metastasis were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and transwell assays. Western blot assay was used to measure the protein levels of Ki67, matrix metallopeptidase 9 (MMP9) and GAB1. Dual-luciferase reporter assay and RNA immune co-precipitation (RIP) assay were used to verify the interaction between miR-194-5p and circ_0061012 or GAB1. Circ_0061012 abundance was significantly enhanced in lesional skin samples from psoriasis patients than that in normal skin specimens from healthy volunteers. Interleukin-22 (IL-22) treatment increased the expression of circ_0061012 in a dose-dependent manner. Circ_0061012 silencing alleviated IL-22-induced promoting effects in the proliferation, migration and invasion of HaCaT cells. Circ_0061012 interacted with miR-194-5p, and miR-194-5p knockdown counteracted circ_0061012 silencing-mediated influences in IL-22-induced HaCaT cells. GAB1 was a target of miR-194-5p in HaCaT cells, and miR-194-5p hampered proliferation and metastasis which were induced by IL-22 partly through targeting GAB1. Circ_0061012 elevated the expression of GAB1 through sponging miR-194-5p in HaCaT cells. Circ_0061012 accelerated IL-22-induced proliferation and metastasis in HaCaT cells through enhancing GAB1 expression via sponging miR-194-5p in psoriasis.     

Circ_0004712 promotes endometriotic epithelial cell proliferation,migration and invasion by regulating miR-488-3p/ROCK1 axis in vitro

Recent evidence indicates that circular RNAs (circRNAs) play crucial regulatory roles in the pathogenesis and development of endometriosis. Circ_0004712 was found to be differentially expressed in endometriosis. However, the detailed function and mechanism of circ_0004712 in endometriosis are still unclear. Quantitative real-time polymerase chain reaction and Western blot were used for the detection of circ_0004712, miR-488-3p and ROCK1 (Rho Associated Coiled-Coil Containing Protein Kinase 1) levels. In vitro experiments in endometrial endothelial cells were performed by cell counting kit-8, EdU, transwell, wound healing assays, and flow cytometry, respectively. The molecular mechanism of circ_0004712 function was investigated using bioinformatics target predication, dual-luciferase reporter, and RNA immunoprecipitation (RIP) assays. The expression of circ_0004712 was higher in endometriotic endometrial tissues and epithelial cells. Knockdown of circ_0004712 suppressed cell proliferation, migration, invasion, EMT process and induced apoptosis in ectopic endometrial epithelial cells in vitro. Mechanistically, circ_0004712 acted as a ceRNA to sponge miR-488-3p, thus elevating the expression of ROCK1, which was confirmed to be a target of miR-488-3p. Rescue experiments suggested that miR-488-3p inhibition reversed the inhibitory effects of circ_0004712 silencing on cell growth and metastasis. Moreover, miR-488-3p restoration restrained the proliferation and metastasis in ectopic endometrial epithelial cells, which were attenuated by ROCK1 overexpression. Circ_0004712 knockdown suppressed the proliferation and metastasis of ectopic endometrial epithelial cells via miR-488-3p/ROCK1 axis in vitro, suggesting a new insight into the pathogenesis of endometriosis.     

Circ_0005615 promotes cervical cancer cell growth and metastasis by modulating the miR-138-5p/KDM2A axis

Cervical cancer (CC) is a highly fatal gynecological malignancy due to its high metastasis and recurrence rate. Circular RNA (circRNA) has been regarded as a regulator of CC. However, the underlying molecular mechanism of circ_0005615 in CC remains unclear. The levels of circ_0005615, miR-138-5p, and lysine demethylase 2A (KDM2A) were measured using qRT-PCR or western blot. Cell proliferation was assessed by Cell Counting Kit-8, 5-ethynyl-2′-deoxyuridine, and colony formation experiments. Cell invasion and migration were tested by transwell assay and wound healing assay. Flow cytometry and Caspase-Glo 3/7 Assay kit were used to analyze cell apoptosis. The expression of proliferation-related and apoptosis-related markers was detected by western blot. The binding relationships among circ_0005615, miR-138-5p, and KDM2A were verified by dual-luciferase reporter assay or RNA immunoprecipitation assay. Xenograft assay was applied to detect the effect of circ_0005615 in vivo. Circ_0005615 and KDM2A were upregulated, while miR-138-5p was downregulated in CC tissues and cells. Circ_0005615 knockdown retarded cell proliferation, migration, and invasion, while promoting apoptosis. Besides, circ_0005615 sponged miR-138-5p, and miR-138-5p could target KDM2A. miR-138-5p inhibitor reversed the regulation of circ_0005615 knockdown on CC cell growth and metastasis, and KDM2A overexpression also abolished the inhibitory effect of miR-138-5p on CC cell growth and metastasis. In addition, we also discovered that circ_0005615 silencing inhibited CC tumor growth in vivo. Circ_0005615 acted as a tumor promoter in CC by regulating the miR-138-5p/KDM2A pathway.     

Hsa_circ_0088212-mediated miR-520 h/APOA1 axis inhibits osteosarcoma progression

BackgroundIt has been known for decades that circRNAs are deregulated in cancer. Here, we characterized the role and underlying mechanism of circ_0088212 in osteosarcoma.MethodsThe expression levels of circ_0088212, miR-520 h, and APOA1 were determined by RT-qPCR. RNase R digestion was performed to verify the circular structure of circ_0088212. CCK8 and transwell invasion assays were conducted to examine the in vitro malignancy of osteosarcoma. Caspase-3 activity was also measured.An in vivo model of osteosarcoma was constructed to examine the in vivo effect of circ_0088212 on osteosarcoma. Luciferase reporter, RNA RIP, and RNA pull-down assays were performed to verify the interaction between miR-520 h and APOA1 or circ_0088212.ResultsCirc_0088212 and APOA1 were expressed at low levels in osteosarcoma tissues and cells, while miR-520 h was highly expressed. Overexpression of circ_0088212 was found to inhibit the in vitro and in vivo growth of osteosarcoma. Mechanistically, miR-520 h was the target of circ_0088212 and APOA1 was the target of miR-520 h. Circ_0088212 downregulated miR-520 h expression, while miR-520 h overexpression abolished the inhibitory effect of circ_0088212 on osteosarcoma cell proliferation and migration. Furthermore, miR-520 h overexpression led to reduced APOA1 expression, while APOA1 overexpression counteracted the oncogenic effect of miR-520 h in osteosarcoma cells.ConclusionOur findings demonstrated that circ_0088212 might exert a tumor-suppressive activity in osteosarcoma by sponging and sequestering miR-520 h away from APOA1. This suggests that the circ_0088212/miR-520 h/APOA1 axis may be a promising therapeutic target for osteosarcoma intervention.     

Hsa_circ_0088212-mediated miR-520 h/APOA1 axis inhibits osteosarcoma progression

BackgroundIt has been known for decades that circRNAs are deregulated in cancer. Here, we characterized the role and underlying mechanism of circ_0088212 in osteosarcoma.MethodsThe expression levels of circ_0088212, miR-520 h, and APOA1 were determined by RT-qPCR. RNase R digestion was performed to verify the circular structure of circ_0088212. CCK8 and transwell invasion assays were conducted to examine the in vitro malignancy of osteosarcoma. Caspase-3 activity was also measured.An in vivo model of osteosarcoma was constructed to examine the in vivo effect of circ_0088212 on osteosarcoma. Luciferase reporter, RNA RIP, and RNA pull-down assays were performed to verify the interaction between miR-520 h and APOA1 or circ_0088212.ResultsCirc_0088212 and APOA1 were expressed at low levels in osteosarcoma tissues and cells, while miR-520 h was highly expressed. Overexpression of circ_0088212 was found to inhibit the in vitro and in vivo growth of osteosarcoma. Mechanistically, miR-520 h was the target of circ_0088212 and APOA1 was the target of miR-520 h. Circ_0088212 downregulated miR-520 h expression, while miR-520 h overexpression abolished the inhibitory effect of circ_0088212 on osteosarcoma cell proliferation and migration. Furthermore, miR-520 h overexpression led to reduced APOA1 expression, while APOA1 overexpression counteracted the oncogenic effect of miR-520 h in osteosarcoma cells.ConclusionOur findings demonstrated that circ_0088212 might exert a tumor-suppressive activity in osteosarcoma by sponging and sequestering miR-520 h away from APOA1. This suggests that the circ_0088212/miR-520 h/APOA1 axis may be a promising therapeutic target for osteosarcoma intervention.     

Circ_0021573 acts as a competing endogenous RNA to promote the malignant phenotypes of human ovarian cancer cells

Circular RNAs (circRNAs) have been reported to be implicated in the tumorigenesis and progression of ovarian cancer. Here, the study was designed to explore the activity of human circ_0021573 in ovarian cancer pathogenesis and its regulation through the competing endogenous RNA (ceRNA) crosstalk. Circ_0021573, microRNA (miR)? 936, and cullin 4B (CUL4B) were quantified by qRT-PCR and western blot. Cell proliferation ability was detected by XTT, 5-Ethynyl-2′-Deoxyuridine (EdU), and colony formation assays. Cell apoptosis, migration, and invasion were assessed by flow cytometry, wound-healing, and transwell assays, respectively. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were used to evaluate the direct relationship between miR-936 and circ_0021573 or CUL4B 3′UTR. Xenograft studies were applied to assess the role of circ_0021573 in tumor growth. Our data showed that circ_0021573 expression is enhanced in human ovarian cancer. Inhibition of circ_0021573 impedes cell proliferation, migration, and invasion and promotes apoptosis in vitro, as well as diminishes tumor growth in vivo. Mechanistically, circ_0021573 contains a miR-936 binding site, and miR-936 is a relevant mediator of circ_0021573 regulation. MiR-936 direct targets and inhibits CUL4B. MiR-936-mediated suppression of CUL4B hinders cell proliferation, migration, and invasion and accelerates apoptosis in vitro.. These data suggested that circ_0021573 might promote the malignant phenotypes of ovarian cancer cells by functioning as a ceRNA for miR-936 to induce CUL4B, which provided a promising target for the prevention and inhibition of ovarian cancer.     

Circ_0004015 silencing represses cisplatin chemoresistance and tumor progression by reducing KLF8 in a miR-198-dependent manner in non-small cell lung cancer

Circular RNA (circRNA) plays vital roles in diverse cancer progression, including non-small cell lung cancer (NSCLC). Herein, the role of circ_0004015 in regulating the sensitivity of NSCLC to cisplatin (DDP) is revealed. The RNA expression of circ_0004015, microRNA-198 (miR-198) and kruppel like factor 8 (KLF8) was detected by quantitative real-time polymerase chain reaction. Protein expression was checked by western blot. The half maximal inhibitory concentration of DDP and cell proliferation were determined by cell counting kit-8 assay. Cell colony formation ability, migration, invasion and apoptosis were investigated by colony-forming assay, transwell assay and flow cytometry analysis, respectively. The effect of circ_0004015 knockdown on DDP sensitivity in vivo was demonstrated by mouse model assay. The interactions among circ_0004015, miR-198 and KLF8 were predicted by bioinformatics methods, and identified by mechanism assays. The expression of circ_0004015 and KLF8 was apparently upregulated, while miR-198 expression was downregulated in DDP-resistant NSCLC tissues and cells compared with control groups. Additionally, circ_0004015 silencing repressed DDP resistance, cell proliferation, migration and invasion, but induced cell apoptosis in DDP-resistant NSCLC cells. Circ_0004015 knockdown promoted the effect of DDP on tumor formation in vivo. Also, miR-198 inhibitors attenuated circ_0004015 depletion-mediated action though associating with circ_0004015. MiR-198 regulated DDP sensitivity and NSCLC progression by targeting KLF8. Furthermore, circ_0004015 modulated KLF8 expression through interaction with miR-198. Circ_0004015 conferred DDP resistance and promoted NSCLC progression by miR-198/KLF8 pathway, proving a potential target for studying DDP-mediated treatment of NSCLC.     

Hsa_circ_0088212-mediated miR-520 h/APOA1 axis inhibits osteosarcoma progression

BackgroundIt has been known for decades that circRNAs are deregulated in cancer. Here, we characterized the role and underlying mechanism of circ_0088212 in osteosarcoma.MethodsThe expression levels of circ_0088212, miR-520 h, and APOA1 were determined by RT-qPCR. RNase R digestion was performed to verify the circular structure of circ_0088212. CCK8 and transwell invasion assays were conducted to examine the in vitro malignancy of osteosarcoma. Caspase-3 activity was also measured.An in vivo model of osteosarcoma was constructed to examine the in vivo effect of circ_0088212 on osteosarcoma. Luciferase reporter, RNA RIP, and RNA pull-down assays were performed to verify the interaction between miR-520 h and APOA1 or circ_0088212.ResultsCirc_0088212 and APOA1 were expressed at low levels in osteosarcoma tissues and cells, while miR-520 h was highly expressed. Overexpression of circ_0088212 was found to inhibit the in vitro and in vivo growth of osteosarcoma. Mechanistically, miR-520 h was the target of circ_0088212 and APOA1 was the target of miR-520 h. Circ_0088212 downregulated miR-520 h expression, while miR-520 h overexpression abolished the inhibitory effect of circ_0088212 on osteosarcoma cell proliferation and migration. Furthermore, miR-520 h overexpression led to reduced APOA1 expression, while APOA1 overexpression counteracted the oncogenic effect of miR-520 h in osteosarcoma cells.ConclusionOur findings demonstrated that circ_0088212 might exert a tumor-suppressive activity in osteosarcoma by sponging and sequestering miR-520 h away from APOA1. This suggests that the circ_0088212/miR-520 h/APOA1 axis may be a promising therapeutic target for osteosarcoma intervention.     

Circ_0027599/PHDLA1 suppresses gastric cancer progression by sponging miR-101-3p.1

Background

Pleckstrin homology-like domain family A member 1 (PHLDA1) is a tumor suppressor gene in gastric cancer, but its role regulated by circular RNAs (circRNAs) is not known. CircRNAs are important regulators in cancer growth and progression, however, the molecular roles of circRNAs in gastric cancer are rarely known. The study was aimed to investigate the role of circRNAs in regulating PHLDA1 expression in gastric cancer.

Results

The circRNA expression profile in the gastric cancer tissues by circRNA microarray showed that hsa_circ_0027599 (circ_0027599) was significantly down-regulated in gastric cancer patients and cells when comparing with the controls. Circ_0027599 overexpression suppressed gastric cancer cell proliferation and metastasis. By using bioinformatics tools and luciferase reporter assays, circ_0027599 was verified as a sponge of miR-101-3p.1 (miR-101) and suppressed cancer cell survival and metastasis. It was also verified that PHLDA1 was regulated by circ_0027599 in gastric cancer cells.

Conclusions

The study uncovered that PHLDA1 was regulated by circ_0027599/miR-101, which suppressed gastric cancer survival and metastasis in gastric cancer.

     

Circ_0025039 acts an oncogenic role in the progression of non-small cell lung cancer through miR-636-dependent regulation of CORO1C

Non-small cell lung cancer remains the leading cause of cancer-related death worldwide. Circular RNA plays vital roles in NSCLC progression. This study is designed to reveal the role of circ_0025039 in NSCLC cell malignancy. The RNA expression of circ_0025039, microRNA-636 (miR-636), and coronin 1C was detected by quantitative real-time polymerase chain reaction. Protein expression was checked by Western blot analysis or immunohistochemistry assay. Cell proliferation, migration, invasion, tube formation ability, sphere formation capacity, and apoptosis were investigated by cell counting kit-8, 5-Ethynyl-29-deoxyuridine, transwell assay, tube formation assay, sphere formation assay, and flow cytometry analysis, respectively. Mouse model assay was conducted to reveal the effect of circ_0025039 silencing on tumor formation in vivo. The interaction between miR-636 and circ_0025039 or CORO1C was identified through dual-luciferase reporter and RNA pull-down assays. The expression of circ_0025039 and CORO1C was significantly increased, while miR-636 was decreased in NSCLC tissues and cells compared with controls. Circ_0025039 depletion repressed NSCLC cell proliferation, migration, invasion, tube-forming capacity, and sphere formation ability, but induced cell apoptosis. The neoplasm formation was repressed after circ_0025039 silencing. Additionally, circ_0025039 acted as a sponge for miR-636, which was found to target CORO1C. Importantly, the contribution of circ_0025039 to NSCLC progression was mediated by miR-636/CORO1C axis. Circ_0025039 silencing repressed NSCLC malignant progression by reducing CORO1C expression through miR-636, showing the possibility of circ_0025039 as a therapeutic target for NSCLC.

     

Circular RNA circ_0032962 promotes trophoblast cell progression as ceRNA to target PBX3 via sponging miR-326 in preeclampsia

Preeclampsia (PE) is the leading cause of maternal deaths in primipara. It is mainly characterized by defect migration and invasion of trophoblast cells. Circular RNAs (circRNAs) have been widely reported to be associated with PE progression. This study is designed to explore the role and mechanism of circ_0032962 on trophoblast cell behavior. Circ_0032962, microRNA-326 (miR-326), and Pre-B-cell leukemia homeobox 3 (PBX3) levels were measured by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation ability, migration, and invasion were measured by Cell Counting Kit-8 (CCK-8), 5-ethynyl-2′-deoxyuridine (EdU), Colony formation, wound healing, and transwell assays. Protein levels of E-cadherin, Vimentin, N-cadherin, and PBX3 were examined by western blot assay. The binding relationship between miR-326 and circ_0032962 or PBX3 was predicted by circular RNA Interactome or Starbase and then verified by a dual-luciferase reporter assay. Circ_0032962 and PBX3 levels were declined in placenta tissues from preeclampsia patients, and miR-326 was elevated. Apart from that, circ_0032962 knockdown could suppress cell proliferation ability, migration, invasion, and epithelial-mesenchymal transition (EMT) in trophoblast cells. Mechanically, circ_0032962 could affect PBX3 expression through sponging miR-326. Circ_0032962 could contribute to trophoblast cell growth ability and metastasis partly by regulating the miR-326/PBX3 axis, providing a novel insight into the pathogenesis and treatment of PE.     

Circ-CSPP1 knockdown suppresses hepatocellular carcinoma progression through miR-493-5p releasing-mediated HMGB1 downregulation

BackgroundHepatocellular carcinoma (HCC) accounts for over 80% of primary liver cancers and leads to a high death rate. Research on circular RNAs (circRNAs) suggests that circRNAs are promising biomarkers for cancer treatment. This study aimed to explore the function of a novel circRNA (circ-CSPP1) in HCC.MethodsCirc-CSPP1 was obtained from the microarray data downloaded from the Gene Expression Omnibus (GEO) database. The expression of circ-CSPP1, miR-493-5p and high mobility group box 1 (HMGB1) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation, colony formation ability, migration and invasion were monitored using cell counting kit-8 (CCK-8) assay, colony formation assay, wound healing assay and transwell assay, respectively. The protein levels of CyclinD1, Vimentin, matrix metallopeptidase 9 (MMP-9) and HMGB1 were detected by western blot. Xenograft models were established to investigate the function of circ-CSPP1 in vivo. The association between miR-493-5p and circ-CSPP1 or HMGB1 was predicted by the online tool starBase and ensured by dual-luciferase reporter assay.ResultsThe expression of circ-CSPP1 and HMGB1 was elevated, while the expression of miR-493-5p was declined in HCC tissues and cells. Circ-CSPP1 knockdown not only depleted HCC cell proliferation, formation, migration and invasion in vitro but also inhibited tumor growth in vivo. MiR-493-5p was a target of circ-CSPP1, and HMGB1 was a target of miR-493-5p. Rescue experiments presented that miR-493-5p deficiency reversed the effects of circ-CSPP1 knockdown, and HMGB1 overexpression reversed the effects of miR-493-5p restoration. Circ-CSPP1 sponged miR-493-5p to regulate HMGB1 expression.ConclusionKnockdown of circ-CSPP1 suppressed HCC development both in vitro and in vivo by upregulation of miR-493-5p and downregulation of HMGB1, hinting that circ-CSPP1 participated in HCC pathogenesis.     

Circ_0101692 knockdown retards the development of clear cell renal cell carcinoma through miR-384/FN1 pathway

PurposeCircular RNA_0101692 (circ_0101692) is overexpressed in clear cell renal cell carcinoma (ccRCC) by microarray analyses. However, its function and action mechanism in ccRCC tumorigenesis is still elusive.MethodsWestern blotting and qRT-PCR were executed to assess the circ_0101692, miR-384 and FN1 expression in ccRCC cells and tissues. Target relationships among them were determined via dual luciferase reporter and/or RNA immunoprecipitation assays. Cell proliferation was evaluated by CCK-8 assay. Caspase-3 activity assay was utilized to analyze cell apoptosis. To find out whether ccRCC cells might migrate, a transwell assay was performed. To assess the effects of circ_0101692 on tumor development in vivo, a mouse xenograft model was used.ResultsHigh expression of circ_0101692 and FN1, and decreased miR-384 were determined in ccRCC. Cell growth, migration and viability were decreased whereas cell apoptosis was stimulated when circ_0101692 was knockdown. miR-384 inhibitor transfection attenuated the inhibiting impacts of circ_0101692 silencing on ccRCC cell progression. FN1 deletion further inverted the cancer-promoting effect of miR-384 downregulation on cell viability and migration. In addition, circ_0101692 could sponge miR-384 to relieve the inhibition of miR-384 on FN1 in ccRCC.ConclusionsCirc_0101692 targeted miR-384/FN1 axis to facilitate cell proliferation, migration and repress apoptosis, thereby accelerating the development of ccRCC. This points out that circ_0101692/miR-384/FN1 axis might be a prospective target implemented for the future treatment of ccRCC.     

Circ_0015756 promotes ovarian cancer progression via the miR-145–5p/PSAT1 axis

Circular RNA (circRNA) have been shown to exert vital functions in the pathological progressions of ovarian cancer (OC). Herein, this study aimed to investigate the role and mechanisms of circ_0015756 in OC progression. Levels of circ_0015756, microRNA (miR)? 145–5p and phosphoserine aminotransferase 1 (PSAT1) were detected using quantitative real-time polymerase chain reaction, Western blot or immunohistochemistry assays. Cell proliferation, apoptosis, migration and invasion were determined using cell counting kit-8, 5-Ethynyl-2′-Deoxyuridine (Edu) incorporation, flow cytometry, transwell and Western blot assays. The binding interaction between miR-145–5p and circ_0015756 or PSAT1 was confirmed by bioinformatics prediction and dual-luciferase reporter assay. Tumor formation assay in nude mice was performed to determine the tumor growth in vivo. Circ_0015756 was highly expressed in OC tissues and cells. Knockdown of circ_0015756 suppressed cancer cell growth, migration and invasion in vitro, as well as impeded tumor growth in vivo. In a mechanical study, circ_0015756 directly bound to miR-145–5p, and inhibition of miR-145–5p reversed the effects of circ_0015756 knockdown on OC cells. Moreover, miR-145–5p directly targeted PSAT1, and miR-145–5p weakened OC cell growth, migration and invasion via targeting PSAT1. Importantly, further studies confirmed that circ_0015756 could indirectly regulate PSAT1 expression via sponging miR-145–5p. In all, circ_0015756 accelerated OC tumorigenesis through regulating miR-145–5p/PSAT1 axis, providing a new therapeutic target for OC.     

Circ_0005075 promotes hepatocellular carcinoma progression by suppression of microRNA-335

Accumulating evidence suggests that noncoding RNAs play a vital role in cancer biology. Circular RNAs (circRNAs), a newly defined class of endogenously widespread noncoding RNAs, have been intensively reported to influence cell function and development, and even cancer prognosis by sponging microRNAs in various types of cancer. Nevertheless, the circRNAs research in hepatocellular carcinoma (HCC) still remains far insufficient. Herein, we investigated the role of a newly defined circRNAs, circ_0005075, in HCC development. We found circ_0005075 was upregulated in HCC tissues. HCC progression was suppressed by downregulation of circ_0005075 in vitro and in vivo, and the suppression was partially reversed by inhibition of microRNA-335 (miR-335) expression. Further, we found the expression of mitogen-activated protein kinase 1 (MAPK1) was substantially regulated by circ_0005075 and miR-335. Mechanically, it was demonstrated that circ_0005075 could directly bind to miR-335 and miR-335 could bind to MAPK1. Our data provide evidence that circ_0005705 promotes the HCC progression by sponging miR-335 and further regulating MAPK1 expression.