Circular RNA circ_0034642 elevates BATF3 expression and promotes cell proliferation and invasion through miR-1205 in glioma

Growing evidence indicates that circular RNA (circRNA) plays an important role in the regulation of tumor biological behaviors. In this study, we aimed to explore the role of a novel circRNA, circ_0034642, in glioma. qRT-PCR was conducted to evaluate the levels of circ_0034642 in glioma tissues and cells. In addition, the clinical severity and prognostic role of circ_0034642 were illustrated. Functionally, loss and gain-of function assays were performed by CCK-8, colony-forming, flow cytometric and transwell experiments in glioma cells. Moreover, luciferase reporter assay was used to detect the mechanism of circ_0034642. Circ_0034642 was upregulated in glioma tissues and cell lines. Overexpressed circ_0034642 was correlated with adverse phenotypes in the patients with glioma. In addition, circ_0034642 could be regarded as a prognostic predictor for glioma patients. Moreover, circ_0034642 could promote cell proliferation, migratory and invasive capacities and inhibit cell apoptosis. For the mechanism investigation, circ_0034642 was proved to be a sponge of miR-1205, and miR-1205 could regulate BATF3 expression via targeting 3′UTR of BATF3. Rescue assays also illustrated that the oncogenic function of circ_0034642 is partly attributed to its modulation on miR-1205/BATF3 axis. Collectively, circ_0034642/miR-1205/BATF3 pathway may play an important role in glioma.     

Hsa_circ_0076931 suppresses malignant biological properties,down-regulates miR-6760-3p through direct binding,and up-regulates CCBE1 in glioma

The function of circular RNAs (circRNAs) in gliomas is as yet unknown. The present study explored role of hsa_circ_0076931 in glioma. circRNA expression profiles were identified via RNA-seq followed by qRT-PCR validation in three pairs of glioma and normal brain tissues (NBT). The function of hsa_circ_0076931 was investigated in vitro using cell lines as well as in vivo using a xenograft tumor. Hsa_circ_0076931 was up-regulated by overexpression and an mRNA profile compared with wild-type was identified by RNA-seq. The relationship between miR-6760-3p and hsa_circ_0076931 or CCBE1 was confirmed via luciferase reporter or AGO2-RIP assays. A total of 507 circRNAs were identified in glioma tissues that were differentially expressed compared with that in NBT, and the sequencing data were deposited in BioProject (ID: PRJNA746438). Hsa_circ_0007694 and hsa_circ_0008016 were memorably increased whereas hsa_circ_0076931 and hsa_circ_0076948 decreased in glioma compared with those in NBT. Additionally, hsa_circ_0076931 expression was negatively correlated with histological grade. Overexpression of hsa_circ_0076931 inhibited proliferation, migration, and invasion while promoting apoptosis of glioma cells. A total of 4383 and 537 aberrantly expressed genes were identified between the hsa_circ_0076931-overexpressed and control groups in H4 and U118-MG cells, respectively; the sequencing data were deposited in BioProject (ID: PRJNA746438). These differentially expressed genes were mainly enriched in cancer-related pathways. In addition, elevated hsa_circ_0076931 levels induced the expression of CCBE1 while suppressing miR-6760-3p expression. miR-6760-3p can bind to hsa_circ_0076931. The experimental evidence supports using hsa_circ_0076931 as a marker for glioma and to help prevent malignant progression. The mechanism might be relevant to miR-6760-3p and CCBE1.     

Circular RNA hsa_circ_0076248 promotes oncogenesis of glioma by sponging miR-181a to modulate SIRT1 expression

Glioma is one of the most common primary malignancies of the central nervous system, which has aggressive clinical behavior and a poorer prognosis. MicroRNAs (miRs) are a class of small noncoding RNAs that function as mediators of gene expression, which can be sponged by circRNA provided with a closed circular structure. Dysregulations of circular RNAs (circRNAs) and miRs have been implicated in the development and progression of glioma. In the current study, we investigated the role of circular RNA hsa_circ_0076248 in mediating the oncogenesis of glioma by sponging miR-181a to modulate silent information regulator 1 (SIRT1) expression in vitro and in vivo. The quantitative real-time polymerase chain reaction results showed that the expression of miR-181a was significantly decreased in glioma tissues and cell lines compared with normal brain tissues and normal gliocyte, respectively, and the expression of hsa_circ_0076248 and SIRT1 demonstrated the opposite. Bioinformatics analysis identified hsa_circ_0076248 could sponge miR-181a, and miR-181a could target the mRNA of SIRT1. Our results verified that downregulating hsa_circ_0076248 or upregulating miR-181a could depress the proliferation and invasion of glioma in vitro and in vivo. The experiment also showed that downregulating hsa_circ_0076248 or upregulating miR-181a could remarkably promote the temozolomide chemotherapy sensitivity. Furthermore, Western blot analysis testified that downregulating hsa_circ_0076248 or upregulating miR-181a could promote the expression of p53 and SIRT1. In summary, our study sheds light on the regulatory mechanism of hsa_circ_0076248 in glioma growth and invasion via sponging miR-181a, which downregulates the SIRT1 expression and also suggests that hsa_circ_0076248, miR-181a, and SIRT1 may serve as potential therapeutic targets for glioma.     

Circular RNA hsa_circ_101555 promotes hepatocellular carcinoma cell proliferation and migration by sponging miR-145-5p and regulating CDCA3 expression

Circular RNAs have been reported to play significant roles in regulating pathophysiological processes while also guiding clinical diagnosis and treatment of hepatocellular carcinoma (HCC). However, only a few circRNAs have been identified thus far. Herein, we investigated the role of a specific closed-loop structure of hsa_circ_101555 that was generated by back-splicing of the host gene casein kinase 1 gamma 1 (CSNK1G1) in the development and proliferation of HCC. We investigated the expression of Hsa_circ_101555 in HCC and normal tissues using bioinformatics. The expression level of hsa_circ_101555 was further detected by fluorescence in situ hybridization and qRT-PCR in ten HCC patients. Transwell, migration, WST-1 assays, and colony formation assays were used to evaluate the role of hsa_circ_101555 in HCC development and proliferation. The regulatory mechanisms of hsa_circ_101555 in miR-145-5p and CDCA3 were determined by dual luciferase reporter assay. A mouse xenograft model was also used to determine the effect of hsa_circ_101555 on HCC growth in vivo. hsa_circ_101555 showed greater stability than the linear RNA; while in vitro and in vivo results demonstrated that hsa_circ_101555 silencing significantly suppressed cell proliferation, migration, and invasion of HCC cells. Rescue experiments further demonstrated that suppression of miR-145-5p significantly attenuated the biological effects of hsa_circ_101555 knockdown in HCC cells. We also identified a putative oncogene CDCA3 as a potential miR-145-5p target. Thus, our results demonstrated that hsa_circ_101555 might function as a competing endogenous RNA of miR-145-5p to upregulate CDCA3 expression in HCC. These findings suggest that hsa_circ_101555 may be a potential therapeutic target for patients with HCC.Subject terms: Liver cancer, Long non-coding RNAs     

Retracted: Elevation of circular RNA circ-POSTN facilitates cell growth and invasion by sponging miR-1205 in glioma

Glioma is the most common type of primary intracranial tumor. Dysregulation of circular RNAs (circRNAs) plays a critical role in multiple solid tumors. However, the expression profiles of circRNAs and their functions in glioma have been rarely studied. The current work aims to investigate the clinical significance of a novel circRNA, circ-POSTN, in glioma and explore its biological functions and mechanisms in the progression of glioma. We found that circ-POSTN was highly expressed in glioma tissue samples and cells. High circ-POSTN expression was significantly linked to larger tumor size, higher World Health Organization grades, and shorter overall survival. Furthermore, silencing of circ-POSTN in glioma cells could decrease cell growth, migratory and invasive potential, and induce cell apoptosis in LN229 cells. On the contrary, ectopically expressed circ-POSTN induced the opposite effects in the U251 cell line. By bioinformatic prediction and luciferase reporter assay, we identified that miR-1205 could be sponged by circ-POSTN. Further rescue assays demonstrated that the oncogenic functions of circ-POSTN are partly attributed to its regulation of miR-1205 in glioma cells. Taken together, our data suggest that circ-POSTN plays an oncogenic role in glioma progression and may serve as a novel therapeutic target in this deadly disease.     

Hsa_circ_0001495 contributes to cervical cancer progression by targeting miR-526b-3p/TMBIM6/mTOR axis

Cervical cancer (CC) is a common gynecological malignant tumor, causing poor survival rate. Circular RNAs (circRNAs) are abundantly expressed in CC with their stable loop structure. However, the underlying mechanism and biological function of circRNAs remained unclear. Using quantitative real-time polymerase chain reaction (qRT-PCR) or western blot assay, we measured the expression of hsa_circ_0001495, miR-526b-3p, and transmembrane Bax inhibitor motif containing 6 (TMBIM6) in CC tissues and cells. The relationship between miR-526b-3p and hsa_circ_0001495 or TMBIM6 was investigated by bioinformatics analysis, dual-luciferase and RIP analysis. Enzyme linked immunosorbent assay (ELISA) was conducted to evaluate glucose consumption and lactate production. 5-ethynyl-2′-deoxyuridine (EDU) assay were used to test cell proliferation. Cell apoptosis was analyzed by using flow cytometry assay. Transwell and wound-healing assays were used to measure cell invasion and migration. The expression of proteins was examined by western blot. Xenograft assay was applied to detect the effect of hsa_circ_0001495 in vivo. Our finding showed that hsa_circ_0001495 and TMBIM6 expression were upregulated, while miR-526b-3p was downregulated in CC tissues and cell lines. Hsa_circ_0001495 knockdown or TMBIM6 knockdown suppressed cell proliferation, migration, glycolysis, while promoted cell apoptosis in vitro, and hsa_circ_0001495 silence curbed tumor growth in vivo. Beside, hsa_circ_0001495 exerted its function in CC by positively regulating TMBIM6. Furthermore, hsa_circ_0001495 acted as a sponge for miR-526b-3p to regulate TMBIM6 expression. Hsa_circ_0001495/miR-526b-3p/TMBIM6 axis also regulated the phosphorylation of mammalian target of rapamycin (mTOR) in CC cells. In summary, hsa_circ_0001495 regulated the progression of CC by regulating miR-526b-3p/TMBIM6/mTOR pathway.     

Circular RNA hsa_circ_0053277 promotes the development of colorectal cancer by upregulating matrix metallopeptidase 14 via miR-2467-3p sequestration

Colorectal cancer (CRC), a kind of human gastrointestinal cancer, has been reported to be one of the most common malignant tumors worldwide. Increasing evidence has indicated that circular RNAs exert significant effects on the development of multiple cancers. Nevertheless, whether hsa_circ_0053277 regulates the progression of CRC remains to be explored. In this study, our results showed that the expression of hsa_circ_0053277 was markedly upregulated in CRC tissues and cells. Knockdown of hsa_circ_0053277 inhibited cell proliferation, migration, and epithelial-mesenchymal transition (EMT) process in CRC. miR-2467-3p had a binding site for hsa_circ_0053277. Molecular mechanism assays confirmed that hsa_circ_0053277 could bind with miR-2467-3p. In addition, hsa_circ_0053277 accelerated cell proliferation rate by acting as a sponge for miR-2467-3p in CRC. Matrix metalloproteinase 14 (MMP14) expression was notably upregulated in CRC cells and MMP14 was a downstream target gene of miR-2467-3p. Besides, hsa_circ_0053277 positively regulated MMP14 expression while miR-2467-3p negatively regulated MMP14 expression. Rescue assays verified that MMP14 knockdown countervailed the function of miR-2467-3p inhibitor on cell proliferation, migration, and EMT process in CRC. To sum up, hsa_circ_0053277 facilitated the development of CRC by sponging miR-2467-3p to upregulate MMP14 expression.     

Circular RNA hsa_circ_0011385 contributes to cervical cancer progression through sequestering miR-149–5p and increasing PRDX6 expression

Cervical cancer (CC) is a common tumor in the female reproductive tract. Circular RNA hsa_circ_0011385 has been reported to be up-regulated in CC tissues. Nevertheless, the role and regulatory mechanism of hsa_circ_0011385 in CC are still being further verified. The levels of hsa_circ_0011385, microRNA (miR)? 149–5p, and peroxiredoxin 6 (PRDX6) mRNA in CC samples and cell lines were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Loss-of-function experiments were performed to survey the impacts of hsa_circ_0011385 inhibition on CC cell proliferation, colony formation, cycle progression, apoptosis, metastasis, invasion, and angiogenesis. Protein levels were detected by western blotting. The relationship between hsa_circ_0011385 or PRDX6 and miR-149–5p was verified by dual-luciferase reporter, RNA immunoprecipitation (RIP), and/or RNA pull-down assays. The tumorigenesis role of hsa_circ_0011385 in CC was confirmed by xenograft assay. We observed that hsa_circ_0011385 and PRDX6 were up-regulated while miR-149–5p was down-regulated in CC samples and cell lines. CC patients with high hsa_circ_0011385 expression possessed a shorter overall survival. Hsa_circ_0011385 knockdown reduced tumor growth in vivo and facilitated apoptosis, cell cycle arrest, impeded proliferation, metastasis, invasion, and angiogenesis of CC cells in vitro. Hsa_circ_0011385 could mediate PRDX6 expression through binding to miR-149–5p. MiR-149–5p silencing reversed hsa_circ_0011385 knockdown-mediated effects on CC cell angiogenesis and malignancy. PRDX6 overexpression overturned the inhibitory effects of miR-149–5p overexpression on angiogenesis and malignant behaviors of CC cells. In conclusion, hsa_circ_0011385 accelerated angiogenesis and malignant behaviors of CC cells by regulating the miR-149–5p/PRDX6 axis, manifesting that hsa_circ_0011385 might be a therapeutic target for CC.     

Circular RNA hsa_circ_0030018 acts as a sponge of miR-599 to aggravate esophageal carcinoma progression by regulating ENAH expression

Esophageal carcinoma (EC) bears one of the most rapid-growing incidences in cancers, which also has the highest mortality rate worldwide. Multiple studies have authenticated that circular RNAs (circRNAs) significantly work on the progression of cancers. circRNA hsa_circ_0030018 was also verified to exert functions on the development of glioma previously. Nevertheless, the biological function of hsa_circ_0030018 in EC has not been well elucidated yet. In the present study, the results displayed the expression of hsa_circ_0030018 was dramatically increased in EC cells. Inhibition of has_circ_0030018 suppressed cell proliferation, migration, and epithelial-mesenchymal transition (EMT) process in EC. Based on molecular mechanism assays, has_circ_0030018 served as a sponge of miR-599. Enabled homolog (ENAH), which exhibited high expression in EC cells, was confirmed to be a downstream target gene of miR-599. Additionally, has_circ_0030018 positively regulated ENAH expression while miR-599 negatively regulated ENAH expression. Finally, by employing rescue assays, ENAH deficiency partially counteracted the promoting function of miR-599 silence on cell proliferation, migration, and EMT process in EC cotransfected with sh- has_circ_0030018#1 cells. In conclusion, hsa_circ_0030018 acted as a sponge of miR-599 to aggravate EC progression by regulating ENAH expression. Therefore, hsa_circ_0030018 might serve as a promising biomarker and therapeutic target for EC.     

Hsa_circ_0069094 positively regulates the expression of oncogenic ZNF217 by competitively targeting miR-758–3p to promote the development of breast cancer

To investigate the functions and potential mechanisms of hsa_circ_0069094 in this cancer. The expression of hsa_circ_0069094, zinc finger protein 217 (ZNF217) and microRNA-758–3p (miR-758–3p) was detected by quantitative polymerase chain reaction (qPCR), and the protein level of ZNF217 was detected by western blot. Cell proliferation was assessed using cell counting kit-8 (CCK-8) assay and colony formation assay. Cell cycle progression and cell apoptosis were determined using flow cytometry assay. Cell invasion and cell migration were monitored using transwell assay and wound healing assay. The protein levels of apoptosis-related proteins were quantified by western blot. The putative relationship between miR-758–3p and hsa_circ_0069094 and ZNF217 was confirmed using dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Xenograft model was constructed in mice to explore the role of hsa_circ_0069094 on solid tumor growth.Hsa_circ_0069094 and ZNF217 were highly expressed, while miR-758–3p was poorly expressed in tissues and cells of breast cancer. Hsa_circ_0069094 knockdown or ZNF217 knockdown inhibited cell proliferation, invasion and migration and induced cell apoptosis and cell cycle arrest in breast cancer cells. The inhibitory effects of hsa_circ_0069094 knockdown on cell malignant behaviors were abolished by ZNF217 overexpression. Hsa_circ_0069094 competed with ZNF217 for the binding site of miR-758–3p, and hsa_circ_0069094 positively regulated ZNF217 expression by competitively binding to miR-758–3p. Hsa_circ_0069094 knockdown also blocked solid tumor growth in mice. Collectively, Hsa_circ_0069094 played oncogenic effects in breast cancer by activating the expression of ZNF217 via competitively binding to miR-758–3p, which might be a novel strategy for breast cancer suppression.     

Circular RNA circMAN2B2 facilitates glioma progression by regulating the miR-1205/S100A8 axis

The aim of this study was to research the mechanism of circMAN2B2 in the development of glioma. In our study, we found that circMAN2B2 has a higher expression in glioma tissues and cells, which was negatively related to the overall survival of glioma patients. The cell counting kit-8 assay, 5-ethynyl-2′-deoxyuridine labeling assay, transwell assay, and the nude mice assay indicated that knockdown of circMAN2B2 inhibited the cell proliferation, invasion, migration and decreased tumor size. In terms of mechanism, knockdown of circMAN2B2 increased the expression of miR-1205. Moreover, circMAN2B2 regulated S100A8 expression by inhibiting miR-1205. We also showed that knockdown of S100A8 inhibited cell proliferation, invasion, and migration. Increasing S100A8 expression rescued the effect of si-circMAN2B2. In conclusion, circMAN2B2 could improve cell proliferation, invasion, and migration of the glioma by inhibiting miR-1205 and promoting the expression of S100A8.     

hsa_circ_0003222 accelerates stemness and progression of non-small cell lung cancer by sponging miR-527

The relationship between circular RNA (circRNA) and cancer stem cells (CSCs) is uncertain. We have investigated the combined influence of CSCs, circRNA (hsa_circ_0003222), and immune checkpoint inhibitors in NSCLC progression and therapy resistance. We constructed lung CSCs (LCSCs; PC9 and A549). The effects of hsa_circ_0003222 in vitro were determined by cell counting, colony and sphere formation, and Transwell assays. A tumor xenograft model of metastasis and orthotopic model were built for in vivo analysis. We found that hsa_circ_0003222 was highly expressed in NSCLC tissues and LCSCs. Higher levels of hsa_circ_0003222 were associated with the stage, metastasis, and survival rate of patients with NSCLC. Reduced levels of hsa_circ_0003222 decreased tumor cell proliferation, migration, invasion, stemness-like properties, and chemoresistance. The silencing of hsa_circ_0003222 was found to downregulate PHF21B expression and its downstream, β-catenin by relieving the sponging effect of miR-527. Moreover, silencing hsa_circ_0003222 alleviated NSCLC resistance to anti-programmed cell death-ligand 1 (PD-L1)-based therapy in vivo. Our data demonstrate the significant role of hsa_circ_0003222 in NSCLC cell stemness-like properties. The manipulation of circRNAs in combination with anti-PD-L1 therapy may alleviate NSCLC stemness and progression.Subject terms: Cancer microenvironment, Cancer stem cells     

MicroRNA-383 inhibits anchorage-independent growth and induces cell cycle arrest of glioma cells by targeting CCND1

In recent years, microRNAs (miRNAs) have been proved to be closely related to the tumorigenesis and progression. An increasing number of researches have shown that microRNAs function as oncogenes or tumor suppressor genes in human malignant tumors. This study aims to explore the effects of microRNA-383 (miR-383) on malignant biological function of human gliomas. We detected the expression of miR-383 in glioma tissues and normal brain tissues by quantitative real-time PCR. Anchorage-independent growth assays, and flow cytometry were used to evaluate the functions of miR-383 that involves in cell growth and cell cycle. Western blotting assay was used to examine protein expression levels of Cyclin D1 (CCND1), a cell cycle-associated oncogene which has a predicted binding site of miR-383 within its 3′-untranslated region (3′-UTR), and luciferase activity assay was used to evaluate the 3′-UTR activity of CCND1. In this study, we found that miR-383 expression level was lower in gliomas than normal brain tissues. Overexpression of miR-383 in U251 and U87 cells showed a significant inhibitory effect on cell growth, which accompanied with cell cycle G0/G1 arrest as well as downregulation of CCND1 expression. Moreover, CCND1 was verified to be one of the direct targets of miR-383. In summary, this study suggested that miR-383 plays the role of tumor suppressor by targeting CCND1 in glioma cells, and may be useful for developing a new therapeutic strategy for gliomas.     

Hsa_circ_0136666 activates Treg-mediated immune escape of colorectal cancer via miR-497/PD-L1 pathway

PurposeIn the rankings of cancer mortality and incidence worldwide, colorectal cancer ranks fourth and the third, respectively. Circular RNA hsa_circ_0136666 (hsa_circ_0136666) is reported to participate in the growth of colorectal cancer. However, the mechanism by which hsa_circ_0136666 regulates the tumorigenesis of colorectal cancer needs to be further explored. In this study, we report here the role of hsa_circ_0136666 in the aberrant activation of Treg cells and immune evasion of tumor cells, providing a new strategy for the treatment of colorectal cancer.MethodsWestern blotting assay and qRT-PCR assay were used to determine protein and mRNA expression levels. Dual-luciferase reporter assay was used to evaluate the targeted regulatory relationship. RNA immunoprecipitation was used to detect RNA binding. Colony formation assay was utilized to measure the cell proliferation. Flow cytometry was used to assess cell apoptosis. Xenograft model was setup to evaluate tumor growth.ResultsThe results showed that hsa_circ_0136666 and PD-L1 was increased in colorectal cancer cells while miR-497 was decreased in colorectal cancer cells when compared with normal colon epithelial cell line. Hsa_circ_0136666 was demonstrated to directly target miR-497, which also regulated PD-L1 by binding to its 3′UTR. Further mechanistic studies identified that hsa_circ_0136666 controlled cell proliferation and apoptosis via targeting miR-497 and regulating PD-L1 expression. Of note, hsa_circ_0136666 stimulated Treg cells mediated by miR-497/PD-L1 axis and its downstream signal pathway in Treg cells. Finally, hsa_circ_0136666 was found to accelerate the tumor growth in vivo.ConclusionsOur findings demonstrated that hsa_circ_0136666 promoted the expression of PD-L1 by inhibiting miR-497 level in colorectal cancer, thus inducing the activation of Treg cells and leading to the immune escape of tumor, providing a novel mechanistic insight into the pathogenesis of colorectal cancer.     

Circular RNA hsa_circ_0110389 promotes gastric cancer progression through upregulating SORT1 via sponging miR-127-5p and miR-136-5p

Increasing studies have found that circular RNAs (circRNAs) are aberrantly expressed and play important roles in the occurrence and development of human cancers. However, the function of circRNAs on environmental carcinogen-induced gastric cancer (GC) progression remains poorly elucidated. In the present study, hsa_circ_0110389 was identified as a novel upregulated circRNA in malignant-transformed GC cells through RNA-seq, and subsequent quantitative real-time PCR verified that hsa_circ_0110389 was significantly increased in GC tissues and cells. High hsa_circ_0110389 expression associates with advanced stages of GC and predicts poor prognosis. Knockdown and overexpression assays demonstrated that hsa_circ_0110389 regulates proliferation, migration, and invasion of GC cells in vitro. In addition, hsa_circ_0110389 was identified to sponge both miR-127-5p and miR-136-5p and SORT1 was validated as a direct target of miR-127-5p and miR-136-5p through multiple mechanism assays; moreover, hsa_circ_0110389 sponged miR-127-5p/miR-136-5p to upregulate SORT1 expression and hsa_circ_0110389 promoted GC progression through the miR-127-5p/miR-136-5p–SORT1 pathway. Finally, hsa_circ_0110389 knockdown suppressed GC growth in vivo. Taken together, our findings firstly identify the role of hsa_circ_0110389 in GC progression, which is through miR-127-5p/miR-136-5p–SORT1 pathway, and our study provides novel insight for the identification of diagnostic/prognostic biomarkers and therapeutic targets for GC.Subject terms: Gastrointestinal cancer, Non-coding RNAs     

Hsa_circ_0003596 enhances the development of cell renal clear cell carcinoma through the miR-502-5p/IGF1/PI3K/AKT axis

Accumulating research findings have shown that circular RNAs (circRNAs) play an indispensable role in tumorigenesis and tumor progression. The current study aimed to explore the role and modulatory mechanism of hsa_circ_0003596 in clear cell renal cell carcinoma (ccRCC). Quantitative real-time polymerase chain reaction was adopted to detect the expression of hsa_circ_0003596 in ccRCC tissue and cell lines. 5-Ethynyl-2′-deoxyuridine, cell counting kit 8 and the colony formation assay were utilized to assess the proliferation potential of the ccRCC cells. Transwell along with wound healing assays were adopted to quantify infiltration coupled with the migration potential of the cells. The current research study found that the circRNA hsa_circ_0003596 was overexpressed in ccRCC tissue and cell lines. Further, result showed that hsa_circ_0003596 was associated with distant metastasis of renal cancer. Notably, the knockdown of hsa_circ_0003596 can lower the proliferation, infiltration and migration potential of ccRCC cells. The results of in vivo experiments found that the reduction of hsa_circ_0003596 significantly hampered the growth of tumors in mice. In addition, it was evident that hsa_circ_0003596 acts as a “molecular sponge” for miR-502-5p to upregulate the expression of the microRNA-502-5p (miR-502-5p) target insulin-like growth factor 1 (IGF1R). Furthermore, it was found that the phosphatidylinositol 3-kinase (PI3K)/AKT signaling was the downstream cascade of hsa_circ_0003596/miR-502-5p/IGF1R cascade, which is partly responsible for the cancer-promoting effect. Overall, the results of the present study showed that hsa_circ_0003596 facilitated the proliferation, infiltration and migration of ccRCC through the miR-502-5p/IGF1R/PI3K/AKT axis. Therefore, it was evident that hsa_circ_0003596 can serve as a possible biomarker and therapeutic target against ccRCC.     

FtMt promotes glioma tumorigenesis and angiogenesis via lncRNA SNHG1/miR-9-5p axis

ObjectiveThis study is to investigate the effects and the mechanisms of mitochondrial ferritin (FtMt) on the glioma tumorigenesis and angiogenesis.MethodsFtMt expression was detected in glioma tissues and cells as well as in nude mouse tissues. Cell proliferation and apoptosis rate were observed following transfection of LV-FtMt or sh-FtMt in glioma cell line. Moreover, glioma cells with FtMt over-expression/knockdown were co-cultured with human umbilical vein endothelial cells (HUVECs) to observe its function on HUVEC proliferation, angiogenic ability and the vascular endothelial growth factor (VEGF) content. Gain and loss of function of small nucleolar RNA host gene 1 (SNHG1) and miR-9-5p were performed in glioma cells and GBM nude mice to observe its effect on glioma cell proliferation and HUVEC angiogenic ability. Luciferase reporter gene and RIP assay were employed to inspect the interactions among SNHG1, FtMt and miR-9-5p. Additionally, a xenograft mouse model was applied to determine the role of FtMt in glioma.ResultsIn this work, FtMt was strongly expressed in glioma tissues and cells as well as in nude mouse tumor tissues. The employment of the loss-of and gain-of functions assays illustrated that FtMt enhanced glioma tumorigenesis and angiogenesis. Mechanistically, our findings showed that FtMt positively related to SNHG1 while negatively correlated with miR-9-5p, and both SNHG1 and FtMt can competitively bind with miR-9-5p. Besides, the inhibition effects of sh-FtMt on glioma were surveyed in vivo experiments.ConclusionEvidence in this study suggested that FtMt promotes glioma tumorigenesis and angiogenesis via SNHG1 mediated miR-9-5p expression, which may provide a theoretical basis for glioma treatment.     

Hsa_circ_0000119 promoted ovarian cancer development via enhancing the methylation of CDH13 by sponging miR-142-5p

Ovarian cancer is the leading cause of gynecological cancer-related death in women, and is difficult to treat. The aim of our study is to explore the role and action mechanism of hsa_circ_0000119 in ovarian cancer, thus to analyze whether the circular RNA is a potential target for the treatment of the disease. In this present study, our data shows that hsa_circ_0000119 and DNA methyltransferase 1 (DNMT1) was increased, while miR-142-5p was decreased in ovarian cancer. Overexpression of hsa_circ_0000119 promoted tumor growth, while silencing of hsa_circ_0000119 resulted in an opposite effects. Decreasing of hsa_circ_0000119 also notably inhibited the proliferation, migration, and invasion of the ovarian cancer cells. Moreover, the data proves that hsa_circ_0000119 negatively regulated miR-142-5p and cadherin 13 (CDH13) expression, but positively regulated DNMT1 expression. miR-142-5p could interact with hsa_circ_0000119 and DNMT1 3′-UTR. Silencing of DNMT1 could reverse the inhibition of hsa_circ_0000119 to miR-142-5p and CDH13 expression. Importantly, higher level of CDH13 promoter methylation existed in the ovarian tumors than that in matched normal tissues. DNA methyltransferase inhibitor could increase the expression of CDH13 in ovarian cancer cells. In addition, our results also prove that increasing of CDH13 or miR-142-5p effectively reversed the inhibition of hsa _circ_0000119 to the cell malignant phenotypes. Overall, our data demonstrate that hsa_circ_0000119 facilitated ovarian cancer development through increasing CDH13 expression via promoting DNMT1 expression by sponging miR-142-5p. Our data demonstrate the potential role of hsa_circ_0000119 in the treatment of ovarian cancer.     

Circular RNA hsa_circ_0004015 regulates the proliferation,invasion, and TKI drug resistance of non-small cell lung cancer by miR-1183/PDPK1 signaling pathway

Circular RNAs (circRNAs) were recently reported to be involved in the pathogenesis of Non-small cell lung cancer (NSCLC), however, the molecular mechanisms of circRNAs in cell proliferation, invasion and TKI drug resistance remain largely undetermined. Here, we identified hsa_circ_0004015 was upregulated in NSCLC tissues, and was associated with the poor overall survival rate of NSCLC patients. Knockdown of hsa_circ_0004015 significantly decreased cell viability, proliferation, and invasion, whereas overexpression exhibited opposed effects in vivo and in vitro. Furthermore, hsa_circ_0004015 could enhance the resistance of HCC827 to gefitinib. In mechanism, hsa_circ_0004015 acted as a sponge for miR-1183, and PDPK1 was revealed to be target gene of miR-1183. Subsequently, functional assays illustrated that the oncogenic effects of hsa_circ_0004015 was attributed to the regulation of miR-1183/PDPK1 axis. In conclusion, circ_0016760/miR-1183/PDPK1 signaling pathway might play vital roles in the tumorigenesis of NSCLC.