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.     

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_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 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     

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_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.     

Downregulation of hsa_circ_0001681 suppresses epithelial-mesenchymal transition in thyroid carcinoma via targeting to miR-942-5p/TWIST1 signaling pathway

Thyroid carcinoma (TC) seriously threatens the health and safety of patients, and the treatment target of it still is poor. RT-qPCR and Western blot were carried out to detect the expression of genes and proteins, respectively. Cell proliferation was confirmed using colony formation assay. Transwell assay were performed to measure the cell migration and invasion. Besides, luciferase reporter assay was accomplished to ensure the target relationship between miR-942-5p and TWIST1 mRNA as well as hsa_circ_0001681. Here, we proved that hsa_circ_0001681 was increased in TC, and located majorly in the cytoplasm of TC cells. However,  miR-942-5p was decreased in TC, and was negatively correlated with hsa_circ_0001681 expression. Knockdown of hsa_circ_0001681 significantly repressed the proliferation, migration, invasion and EMT of TC cells. We also found that the process of hsa_circ_0001681 silencing limited EMT, which was obstructed by TWIST1 increasing. Moreover, hsa_circ_0001681 acted as a miRNA sponge and completed with TWIST1 mRNA for binding to miR-942-5p, thus downregulation of hsa_circ_0001681 repressed EMT and subsequent malignant phenotype of TC cells through targeting miR-942-5p/TWIST1 signaling pathway. Finally, the studies in vivo showed that decreasing of hsa_circ_0001681 effectively inhibited the growth of tumor via repressing EMT by regulating miR-942-5p/TWIST1 signaling pathway. Overall, silencing of hsa_circ_0001681 significantly suppressed TC progression through inhibiting EMT via acting as a miR-942-5p sponge to facilitate the expression of TWIST1. Our data provided a reliable evidence for hsa_circ_0001681 is a potential treatment target in TC.

     

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.     

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.     

CircTP53 promotes colorectal cancer by acting as a miR-876-3p sponge to increase cyclin-dependent kinase-like 3 expression

According to ceRNA theory, circular RNAs could regulate certain protein expression through targeting corresponding microRNAs to affect the progression of multiple diseases, including colorectal cancer. CircTP53 (hsa_circ_0107702), highly expressed in thyroid cancer tissues, could promote the proliferation of thyroid cancer. However, the function of circTP53 in colorectal cancer is still unclear. In our study, we found circTP53 was significantly up-regulated in colorectal cancer tissues from patients and in colorectal cell lines. Next, using colorectal cell lines, we confirmed that circTP53 promoted the proliferation, migration and invasion, and reduced the apoptotic rate. Furthermore, through bioinformatics analysis and experimental confirmation, we found circTP53 functioned as the sponge of miR-876-3p, and miR-876-3p reversed the phenotype of circTP53 on the facilitation of colorectal cancer. Additionally, we found circTP53 promoted the progression of colorectal cancer by elevating the expression of CDKL3. At last, we suggested that circTP53 knockdown could inhibit colorectal cancer progression in vivo. In conclusion, circTP53 was highly expressed in colorectal cancer tissues, and promoted colorectal cancer progression via modulating miR-876-3p/CDKL3 axis.     

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.     

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.     

Downregulation of circDYNC1H1 exhibits inhibitor effect on cell proliferation and migration in hepatocellular carcinoma through miR-140-5p

Circular RNAs have been found to be aberrantly expressed in tumors and their significance in tumorigenesis has been focused on. The role of circDYNC1H1 in hepatocellular carcinoma (HCC) pathogenesis and its relationship with miR-140-5p were explored. The expression of circDYNC1H1, miR-140-5p, and SULT2B1 in HCC tissues and cells was measured, and Pearson's analysis was used to analyze their expression correlation. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Transwell assays were performed to determine cell proliferation and migration. Binding between circDYNC1H1 and miR-140-5p was evaluated with RNA pull-down assay. A luciferase reporter assay was conducted to assess the interaction between circDYNC1H1 and miR-140-5p and between miR-140-5p and SULT2B1. circDYNC1H1 was highly expressed in HCC tissues (n = 20), and it was negatively associated with the expression of miR-140-5p but positively correlated with SULT2B1 messenger RNA expression. circDYNC1H1 was upregulated in cell lines of HCC. Interference of circDYNC1H1 suppressed cell proliferation and migration of HCC. circDYNC1H1 acted as a sponge of miR-140-5p. miR-140-5p controlled SULT2B1 expression by targeting its 3′-untranslated region. circDYNC1H1 enhanced SULT2B1 expression via sponging miR-140-5p. Downregulation of circDYNC1H1 disturbed cell proliferation and migration of HCC through miR-140-5p/SULT2B1 pathway. Silencing of circDYNC1H1 delayed tumor growth in HCC mouse model. Acting like a sponge of miR-140-5p, silenced circDYNC1H1 downregulated SULT2B1 to restrain HCC cell proliferation and migration, which is adverse to HCC growth and progression.     

Autophagy-associated circular RNA hsa_circ_0007813 modulates human bladder cancer progression via hsa-miR-361-3p/IGF2R regulation

Circular RNAs (circRNAs) drive several cellular processes including proliferation, survival, and differentiation. Here, we identified a circRNA hsa_circ_0007813, whose expression was upregulated in bladder cancer. High hsa_circ_0007813 expression was associated with larger tumor size, higher primary tumor T stage, and higher pathologic grade. Survival analysis showed that patients with high hsa_circ_0007813 expression levels had a poorer prognosis. Based on these findings from clinical tissue samples and cell lines, we assumed that hsa_circ_0007813 functioned a vital role in bladder cancer progression. Next, functional experiments revealed that knockdown of hsa_circ_0007813 inhibited proliferation, migration, and invasiveness of bladder cancer cells both in vitro and in vivo. Through extensive bioinformatic prediction and RNA pull-down assays, we identified hsa-miR-361-3p as a competing endogenous RNA of hsa_circ_0007813. Further bioinformatic studies narrowed targets to 35 possible downstream genes. We then found that knockdown of hsa_circ_0007813 led to altered cell autophagy, bringing our attention to IGF2R, one of the possible downstream genes. IGF2R was also known as cation-independent mannose-6-phosphate receptor (CI-M6PR), was discovered to participate in both autophagy and tumor biology. Regarding autophagy has a dominant role in the survival of tumor cells overcoming cellular stress and correlates with tumor progression, investigations were made to prove that hsa_circ_0007813 could regulate IGF2R expression via hsa-miR-361-3p sponging. The potential of hsa_circ_0007813 in regulating IGF2R expression explained its influence on cell behavior and clinical outcomes. Collectively, our data could offer new insight into the biology of circRNA in bladder cancer.Subject terms: Cancer metabolism, Bladder cancer, Macroautophagy, Cell growth, Cell invasion     

Linc-ROR regulates apoptosis in esophageal squamous cell carcinoma via modulation of p53 ubiquitination by targeting miR-204-5p/MDM2

The long intergenic noncoding RNA, regulator of reprogramming (linc-ROR) has been reported to participate in tumorigenesis, while its functions and fundamental mechanisms in esophageal squamous cell carcinoma (ESCC) remain unclear. In this study, gain-of-function assays showed that linc-ROR upregulation enhanced cell viability, promoted cell proliferation, and inhibited apoptosis. Mechanistically, the regulatory network of linc-ROR/miR-204-5p/MDM2 was established with bioinformatics analysis and online databases, then validated via dual-luciferase reporter assays, RNA immunoprecipitation assays in ESCC cells. Linc-ROR positively regulates the expression of MDM2 as a molecular sponge of miR-204-5p. Moreover, results of western blot and coimmunoprecipitation indicated that linc-ROR overexpression enhanced the ubiquitination level of p53, and its downstream apoptosis-related genes have showed higher bcl-2 expression, lower bax, and cleaved caspase-3 expressions, while miR-204-5p could counteract with this effect. Finally, small interfering RNAs tailored to linc-ROR were established to further evaluate its effects on ESCC comprehensively. In summary, this study revealed that linc-ROR modulated cell apoptosis and regulated p53 ubiquitination via targeting miR-204-5p/MDM2 axis, which provides a novel therapeutic insight into treatments for ESCC.