CircPDE7B/miR-661 axis accelerates the progression of human keloid fibroblasts by upregulating fibroblast growth factor 2 (FGF2).

Circular RNAs (circRNAs) are implicated in keloidogenesis and development. We aimed to investigate the role of a new identified phosphodiesterase 7B-derived circRNA (hsa_circ_0002198; henceforth named as PDE7B) in human keloid fibroblasts (HKFs) and to further confirm its mechanism via competing endogenous RNA (ceRNA) network. Transcriptional and translational levels of circPDE7B, microRNA (miR)-661, fibroblast growth factor 2 (FGF2), cleaved caspase3, B-cell lymphoma (bcl)-2, and bcl-2-associated X protein (bax) were detected by real-time quantitative PCR and western blotting. Relationship among circPDE7B, miR-661, and FGF2 was confirmed by bioinformatics algorithm, dual-luciferase reporter assay, RNA immunoprecipitation, RNA pull-down assay, and Spearman's rank correlation analysis. Cell progression was measured by cell counting kit-8 assay, 5-ethynyl-2-deoxyuridine assay, transwell assays, and flow cytometry. Expression of circPDE7B was upregulated in human keloid tissues and HKFs, accompanied with miR-661 downregulation and FGF2 upregulation. High circPDE7B accelerated proliferation, migration, and invasion, and inhibited apoptosis. These effects were paralleled with increased bcl-2 and decreased cleaved caspase3 and bax. Moreover, low circPDE7B played opposite effects to high circPDE7B. Restoring miR-661 could suppress HKFs progression, while blocking miR-661 could facilitate that. Notably, miR-661 was directly sponged by circPDE7B and then directly governed FGF2 gene expression. Deleting miR-661 and re-expressing FGF2 both abrogated the suppression of circPDE7B knockdown in HKFs progression. In conclusion, circPDE7B might contribute to HKFs progression via functioning as ceRNA for miR-661, suggesting a novel circPDE7B/miR-661/FGF2 pathway underlying keloid formation and treatment.

Production and Stabilization of Specific Upregulated Long Noncoding RNA HOXD-AS2 in Glioblastomas Are Mediated by TFE3 and miR-661, Respectively.

Differential expression of long noncoding RNAs (lncRNA) plays a key role in the development of gliomas. Because gliomas are the most common primary central nervous system tumor and glioblastomas have poor prognosis, it is urgent to develop new diagnostic methods. We have previously reported that lncRNA HOXD-AS2, which is specifically up-regulated in gliomas, can activate cell cycle and promote the development of gliomas. It is expected to be a new marker for molecular diagnosis of gliomas, but little is known about HOXD-AS2. Here, we demonstrate that TFE3 and miR-661 maintain the high expression level of HOXD-AS2 by regulating its production and degradation. We found that TFE3 acted as a transcription factor binding to the HOXD-AS2 promoter region and raised H3K27ac to activate HOXD-AS2. As the cytoplasmic-located lncRNA, HOXD-AS2 could be degraded by miR-661. This process was inhibited in gliomas due to the low expression of miR-661. Our study explains why HOXD-AS2 was specifically up-regulated in gliomas, helps to understand the molecular characteristics of gliomas, and provids insights for the search for specific markers in gliomas.

MiR-770-5p, miR-661 and miR-571 expression level in serum and tissue samples of foot ulcer caused by diabetes mellitus type II in Iranian population.

BACKGROUND: Microvascular complications related to diabetes mellitus type II such as foot ulcers are the reason of many mortalities among T2DM patients. The role of microRNAs (miRNAs, miRs) as potent regulators of gene expression is studied in different diseases such as diabetes mellitus and primary studies revealed their importance as early detecting biomarkers. Therefore, in this study it is tried to evaluate the expression level of some miRNAs (miR-770-5p, miR-661 and miR-571) in serum and tissue samples of T2DM related foot ulcer among Iranian patients. METHODS: 30 samples of blood and 30 muscle tissue were collected from T2DM patients suffering foot ulcer (T2DM + FU), 30 blood samples collected from T2DM patients without foot ulcer (T2DM-FU). 30 tissue samples collected from patients with trauma and 30 blood samples were selected as healthy controls. RESULTS: The three studied miRNAs were statistically significant in all groups in comparison to control blood group. Also, comparison between other groups showed a significant increase of all studied miRNAs especially in the blood and tissues of T2DM + FU patients. The only significant correlation detected between the FBS level and miR-571 expression pattern in blood samples of T2DM + FU group. Finally, the results showed that miR-571, -661, and -770 has a statistically significant discriminative character for differentiating T2DM + FU patients from T2DM-FU both in tissue and blood samples. CONCLUSION: Although more studies are essential for certifying these findings, our results showed that miR-770-5p, miR-661 and miR-571 are correlated with the microvascular complications related with T2DM such as foot ulcer.

circPIP5K1A serves as a competitive endogenous RNA contributing to ovarian cancer progression via regulation of miR-661/IGFBP5 signaling.

Increasing evidence demonstrates the crucial regulatory functions of circular RNAs in different cancer types. The major aim of the current study was to establish functions of circPIP5K1A during ovarian cancer. Our results showed an increased expression of circPIP5K1A in both ovarian cancers and cell lines, which was associated with poor prognosis. In functional analyses, downregulation of circPIP5K1A suppressed ovarian cancer cell migration, proliferation, and invasion in vitro. The miR-661 was indicated as a target of circPIP5K1A and insulin-like growth factor-binding protein 5 (IGFBP5) as a target of miR-661. circPIP5K1A silencing triggered downregulation of IGFBP5 through inducing an increase in miR-66 levels, as determined by the luciferase reporter assay. Data from cell counting kit-8, colony formation, wound healing, and Transwell assays showed that overexpression of IGFBP5 effectively reversed the circPIP5K1A depletion effects. The results collectively indicated that circPIP5K1A contributed to ovarian cancer progression via targeting the miR-661/IGFBP5 axis, supporting its utility as a candidate target for therapy of the disease.

Circ_RUSC2 upregulates the expression of miR-661 target gene SYK and regulates the function of vascular smooth muscle cells.

Many studies have identified circRNA as a prospective direction in the field of cardiovascular research. Detection of circRNA expression in different vascular smooth muscle cell (VSMC) phenotypes revealed that circ_RUSC2 is upregulated in proliferative VSMCs. Sequence analysis of circ_RUSC2 showed that there are multiple binding sites of miR-661 on circ_RUSC2, and that SYK is an important target gene of miR-661. MiR-661 expression is downregulated in proliferative VSMCs, whereas the expression of SYK is upregulated. Circ_RUSC2 and miR-661 do not affect each other's expression levels, but circ_RUSC2 can promote the expression of SYK and inhibit the expression of SM22-alpha, whereas miR-661 has the opposite effect. At the same time, VSMC proliferation and migration can be promoted by SYK or circ_RUSC2, but the linear sequence of circ_RUSC2 can not. MiR-661 and circ_RUSC2 siRNAs inhibit VSMC proliferation and migration, and promote cell apoptosis. When an miR-661 mimic or SYK siRNAs were co-transfected with circ_RUSC2 overexpression vector, VSMC proliferation, apoptosis, and migration were not significantly altered. Accordingly, circ_RUSC2 can promote the expression of SYK, a target gene of miR-661, and regulate VSMC proliferation, apoptosis, phenotypic modulation, and migration. These findings will supply a theoretical basis for studying circRNA function in VSMCs, and new ideas for the diagnosis and treatment of cardiovascular diseases.

Gastric Adenocarcinoma Predictive Long Intergenic Non-Coding RNA Promotes Tumor Occurrence and Progression in Non-Small Cell Lung Cancer via Regulation of the miR-661/eEF2K Signaling Pathway.

BACKGROUND/AIMS: Long non-coding RNAs (lncRNAs) play vital roles in carcinogenesis as oncogenes or tumor suppressor genes. This study explored the biological function of lncRNA gastric adenocarcinoma predictive long intergenic non-coding RNA (GAPLINC) in human non-small cell lung cancer (NSCLC). METHODS: GAPLINC expression in NSCLC specimens and cell lines was detected by qRT-PCR and Western blot. The effect of GAPLINC on cell proliferation was investigated using CCK8-assay, colony formation assay, and xenograft model. The effects of GAPLINC on apoptosis and cell cycle were determined using flow cytometry. The mechanism of GAPLINC involved in NSCLC was explored using Western blot, luciferase reporter assay, and RNA fluorescence in situ hybridization. RESULTS: We found that GAPLINC expression was up-regulated in NSCLC tissues and cell lines. Overexpression of GAPLINC was associated with poor prognosis in patients with NSCLC. Silencing of GAPLINC significantly inhibited cell proliferation, promoted apoptosis, and induced cell cycle arrest in the G0/G1 phase. Results from xenograft transplantation showed that GAPLINC silencing inhibited the tumor growth in vivo. Interestingly, GAPLINC silencing decreased the expression of eukaryotic elongation factor-2 kinase (eEF2K) protein both in vivo and in vitro. Bioinformatic analysis and luciferase reporter confirmed that miR-661 targeted GAPLINC and eEF2K 3'-UTR and was negatively correlated with the expression of GAPLINC and eEF2K. CONCLUSION: Our findings indicate that GAPLINC promotes NSCLC tumorigenesis by regulating miR-661/eEF2K cascade and provide new insights for the pathogenesis underlying NSCLC and potential targets for therapeutic strategy.

MiR-661 promotes tumor invasion and metastasis by directly inhibiting RB1 in non small cell lung cancer.

BACKGROUND: Aberrant microRNA expression has been implicated in metastasis of cancers. MiR-661 accelerates proliferation and invasion of breast cancer and ovarian cancer, while impedes that of glioma. Its role in non small cell lung cancer (NSCLC) and underlying mechanism are worthy elucidation. METHODS: Expression of miR-661 was measured with real-time PCR in both NSCLC tissues and cell lines. The effects of miR-661 on migration, invasion and metastasis capacity of NSCLC were evaluated using wound healing, transwell assay and animal models. Dual reporter luciferase assay and complementary experiments were performed to validate RB1 as a direct target of miR-661 for participation in the progression of NSCLC. RESULTS: MiR-661 was upregulated in NSCLC tissues as compared to paired adjacent tissues and associated with shorter overall survival. Furthermore, miR-661 promoted proliferation, migration and metastasis of NSCLC. Then, we identified RB1 as a direct target of miR-661 through which miR-661 affected EMT process and metastasis of NSCLC. RB1 interacted with E2F1 and both could mediate EMT process in NSCLC. CONCLUSION: MiR-661 promotes metastasis of NSCLC through RB/E2F1 signaling and EMT events, thus may serves as a negative prognostic factor and possible target for treatment of NSCLC patient.

MiR-661 inhibits glioma cell proliferation, migration and invasion by targeting hTERT.

In this study, we analyzed the functional role of miR-661 in glioma cell proliferation, migration and invasion. We found that overexpression of miR-661 obviously suppressed the proliferation, migration and invasion of glioma cells. MiRNA target prediction algorithms implied that hTERT is a candidate target gene for miR-661. A fluorescent reporter assay confirmed that miR-661 could lead to hTERT gene silencing by recognizing and specifically binding to the predicted site of the hTERT mRNA 3' untranslated region (3'UTR) specifically. Furthermore, hTERT knockdown significantly decreased the growth and viability of glioma cells. These results indicate that miR-661 can inhibit glioma cell proliferation, migration and invasion by targeting hTERT.

Circular RNA CircSATB2 facilitates osteosarcoma progression through regulating the miR-661/FUS-mediated mRNA of ZNFX1.

Circular RNAs (circRNAs) are a class of non-coding RNAs which take part in the regulation of the initiation and development of different types of cancer. Numerous studies have demonstrated that circRNAs are involved in the progression of osteosarcoma (OS) as well. Thus, we put our emphasis on the exploration of crucial circRNAs in the process of OS initiation and progression. Using RNA sequencing, we found that circSATB2 was highly expressed in OS tissues compared with adjacent normal tissues. Then, we confirmed the high expression of circSATB2 in OS cell lines and OS tissues and its high expression was related to poor prognosis of OS patients. Functional experiments exhibited that circSATB2 promoted OS proliferation and migration in vitro, primary OS model and OS lung metastasis model showed that circSATB2 aggravated OS progression in vivo. Mechanistically, circSATB2 was found to promote OS progression through sponging miR-661 and FUS regulating the mRNA of ZNFX1. Therefore, circSATB2 could act as a prognostic marker and a therapeutic target for osteosarcoma in the future.

Circ_0091822 aggravates ox-LDL-induced endothelial cell injury through targeting the miR-661/RAB22A axis.

BACKGROUND: Endothelial dysfunction is considered to be an important factor in the pathogenesis of atherosclerosis. Circular RNAs (circRNAs) have been confirmed to participate in the development of atherosclerosis. Nevertheless, the role and mechanism of circ_0091822 in atherosclerosis have not been studied yet. METHODS: The expression of circ_0091822, miR-661 and RAB22A were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). The levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were estimated by enzyme-linked immunosorbent assay (ELISA). Cell viability was analyzed by Cell Counting Kit-8 (CCK-8) assay, cell proliferation was evaluated by EdU assay, and cell apoptosis was gauged by flow cytometry. Western blot was performed to assess the protein levels of Bax, Cleaved-caspase-3 and RAB22A. The interaction among miR-661 and circ_0091822 or RAB22A was verified by dual-luciferase reporter assayRESULTS:Ox-LDL enhanced the expression of circ_0091822 in HUVECs. It also constrained proliferation, promotes apoptosis and inflammation in HUVECs, and down-regulation of circ_0091822 attenuated these effects. Mechanically, circ_0091822 could serve as a sponge of miR-661, miR-661 interference rescued circ_0091822 inhibition-mediated effect on the biological functions in ox-LDL-induced HUVECs. Additionally, RAB22A was a target of miR-661, and its overexpression could partially overturn the negative regulation of miR-661 on ox-LDL-treated HUVECs injury. Importantly, circ_0091822 sponged miR-661 to positively regulate RAB22A expression. CONCLUSION: Circ_0091822 contributed to cell injury by targeting miR-661/RAB22A axis in ox-LDL-stimulated HUVECs.

Impact of circ-0000221 in the Pathogenesis of Hepatocellular via Modulation of miR-661-PTPN11 mRNA Axis.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death in Egypt. A deep understanding of the molecular events occurring in HCC can facilitate the development of novel diagnostic and/or therapeutic approaches. In the present study, we describe a novel axis of hsa-circ-0000221-miR-661-PTPN11 mRNA proposed by in silico and in vitro analysis and its role in HCC pathogenesis. We observe a reduction in the expression levels of hsa-circ-0000221 and PTPN11 mRNA in HCC patients' sera tested compared with control subjects. The reduction occurs with a concomitant increase in the expression of miR-661. Furthermore, the introduction of exogenous hsa-circ-0000221 into Hep-G2 or SNU449 cell lines results in detectable decrease in cellular viability and an increase in apoptotic manifestations that is associated with G1 accumulation and CCDN1 overexpression. Altogether, these findings indicate the tumor-suppressive role of hsa-circ-0000221 in HCC, which acts through miR-661 inhibition, along with a subsequent PTPN11 mRNA increase, where PTPN11 is known to inhibit cell proliferation in many forms of cancer. Our study encourages further investigation of the role of circRNAs in cancer and their potential use as molecular biomarkers.

Circ_0016347 modulates proliferation, migration, invasion, cell cycle, and apoptosis of osteosarcoma cells via the miR-661/IL6R axis.

BACKGROUND: Osteosarcoma is a common primary bone tumour in children and adolescents. Circular RNAs (circRNAs) exert vital functions in human diseases, including osteosarcoma. Therefore, we explored the role of circ_0016347 in osteosarcoma. METHODS: The real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression levels of circ_0016347, microRNA-661 (miR-661), and Interleukin-6 receptor (IL6R) in osteosarcoma tissues and cells. The proliferation of osteosarcoma cells was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazol-3-ium bromide (MTT) and EdU experiments. The migration and invasion were determined by transwell assay. The cell cycle distribution and apoptosis were assessed by flow cytometry assay. The association relationships among circ_0016347, miR-661, and IL6R were analyzed by dual-luciferase reporter assays. The western blot assay was employed to assay the protein expression. A xenograft experiment was established to clarify the functional role of circ_0016347 inhibition in vivo. RESULTS: Circ_0016347 was obviously overexpressed in osteosarcoma tissues and cells compared with control groups. The suppression of circ_0016347 impeded proliferation, migration, invasion, and cell cycle and induced apoptosis in osteosarcoma cells, which was overturned by knockdown of miR-661. Consistently, circ_0016347 knockdown repressed tumour growth in vivo. Moreover, miR-661 directly targeted and inhibited IL6R, and the upregulation of IL6R reversed miR-661-induced effects on osteosarcoma cells. Furthermore, circ_0016347 could regulate IL6R expression through miR-661. Inhibition of circ_0016347 also inactivated the Janus kinase 2 (JAK2)/Transcription 3 (STAT3) signalling pathway in osteosarcoma cells by IL6R. CONCLUSION: Circ_0016347 functioned as an oncogene in osteosarcoma at least in part by the miR-661/IL6R axis and JAK2/STAT3 signalling pathway.

Hsa_circ_0103232 promotes melanoma cells proliferation and invasion via targeting miR-661/RAB3D.

Little is known about the role of hsa_circ_0103232 in melanoma. This study researched the role of hsa_circ_0103232 in melanoma progression. Hsa_circ_0103232 expression in clinical tissues of melanoma patients and melanoma cells was detected by qRT-PCR. Hsa_circ_0103232 localization in melanoma cells was visualized by fluorescence in situ hybridization. Hsa_circ_0103232 effect on melanoma cells viability, proliferation, migration, and invasion was explored by cell counting kit-8 (CCK-8) assay, Edu experiment, wound healing assay, and Transwell experiment. RNA pull-down assay and dual-luciferase reporter gene assay were performed to verify the binding of hsa_circ_0103232 with miR-661, and the binding of miR-661 and RAB3D. Xenograft tumor models were constructed. Western blot and immunohistochemistry were used for protein expression detection. Hsa_circ_0103232 expression was increased in melanoma patients, indicating lower overall survival. Hsa_circ_0103232 was mainly expressed in the cytoplasm of melanoma cells. Silencing hsa_circ_0103232 suppressed melanoma cell viability, proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) (P < 0.01). Hsa_circ_0103232 functioned as a sponge of miR-661 to increase RAB3D expression. miR-661 overexpression partially reversed hsa_circ_0103232 promoting effect on melanoma cells viability, proliferation, migration, invasion, and EMT (P < 0.01). In melanoma patients, hsa_circ_0103232 expression was negatively correlated with miR-661 and positively correlated with RAB3D. Silencing hsa_circ_0103232 suppressed melanoma cell growth in vivo and Ki67 and RAB3D expression in xenograft tumors (P < 0.01). Hsa_circ_0103232 is a tumor promoter in melanoma to enhance malignant phenotype and growth in vivo via sponging miR-661/RAB3D. Hsa_circ_0103232 may be a novel target for melanoma treatment.

LINC01426 aggravates the malignant progression of glioma through miR-661/Mdm2 axis.

BACKGROUND: Long intergenic non-protein coding RNA 1426 (LINC01426) is up-regulated in glioma and functions as a tumor promoter. However, the role of LINC01426 in glioma required further exploration. Therefore, this article mainly studied the role and possible mechanism of LINC01426 in glioma. METHODS: The area under the receiver operating characteristic curve was used to determine the diagnostic value of LINC01426. The effect of LINC01426 on tumor growth was analyzed by tumorigenesis assay and immunohistochemical analysis. Bioinformatics analysis, dual-luciferase assay, RNA pull-down, Pearson test, and real-time quantitative PCR (RT-qPCR) were applied to verify the relationship between target genes. The expressions and effects of LINC01426, miR-661 and MDM2 proto-oncogene (Mdm2) in glioma were examined by bioinformatics analysis combined with molecular and functional experiments (RT-qRCR, 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide, clone formation, BrdU, flow cytometry). The expressions of proliferation and apoptosis-related proteins were determined by Western blot. RESULTS: LINC01426, which was high-expressed in glioma and was related to poor prognosis, could be used as a diagnostic marker for glioma. SiLINC01426 inhibited the malignant phenotype of glioma cells in vitro and attenuated tumor growth and PCNA expression in vivo, while the effects of LINC01426 were the opposite. LINC01426 targeted and inversely correlated with miR-661, which was low-expressed in glioma. MiR-661 inhibitor evidently overturned the effect of siLINC01426 on biological functions, proliferation, and apoptosis-related proteins of glioma cells. Mdm2 bound to miR-661. Moreover, siMdm2 reversed the effects of miR-661 inhibitor on the biological characteristics and Mdm2/p53/p21 expression of glioma cells. CONCLUSION: LINC01426 aggravated the malignant progression of glioma through miR-661/Mdm2 axis.

LncRNA C9orf139 can regulate the progression of esophageal squamous carcinoma by mediating the miR-661/HDAC11 axis.

Increasing evidence has indicated that long non-coding RNAs (LncRNAs) play multiple functions in the development of cancer and function as indicators of diagnosis and prognosis. This aim of this study was to investigate the roles LncRNA C9orF139 had in the progression of esophageal squamous carcinoma (ESCC). We found C9orf139 was highly expressed in ESCC and knock down the expression of C9orf139 significantly suppressed cell proliferation, promoted apoptosis, and inhibited migration and invasion. C9orf139 was able to negatively regulate miR-661 expression. At the same time, HDAC11 expression was negatively regulated by miR-661. The C9orf139/miR-661/HDAC11 axis was further involved in regulating the expression of the NF-κB signaling pathway. The association between the C9orf139 knockdown and the reduced tumor growth and size was observed during in vivo study. C9orf139 is highly expressed in ESCC, and is thus qualified to be used as a potential diagnostic and prognostic marker for ESCC. Its promotion of ESCC progression is achieved by mediating the miR-661/HDAC11 axis.

Hsa_Circ_0001947/MiR-661/DOK7 Axis Restrains Non-Small Cell Lung Cancer Development.

Hsa_circ_0001947 is associated with multiple cancers, but its function in non-small cell lung cancer (NSCLC) is ambiguous and needs further research. The targeting relationship among circ_0001947, miR-661, and downstream of tyrosine kinase 7 (DOK7) was predicted by database and further verified by dual-luciferase reporter assay, while their expressions in cancer tissues and cells were detected by quantitative real-time polymerase chain reaction (qRT-PCR). After transfection, cell biological behaviors and expressions of miRNAs, miR-661 and DOK7 were determined by cell function experiments and qRT-PCR, respectively. Circ_0001947 was low-expressed in NSCLC tissues and cells. Circ_0001947 knockdown intensified cell viability and proliferation, induced cell cycle arrest at S phase, suppressed apoptosis and evidently enhanced miR-510, miR-587, miR-661 and miR-942 levels, while circ_0001947 overexpression did the opposite. MiR-661 was a target gene of circ_0001947 that participated in the regulation of circ_0001947 on cell biological behaviors. Furthermore, DOK7, the target gene of miR-661, partly participated in the regulation of miR-661 on cell viability. Hsa_circ_0001947 acts as a sponge of miR-661 to repress NSCLC development by elevating the expression of DOK7.

Lcn2-derived Circular RNA (hsa_circ_0088732) Inhibits Cell Apoptosis and Promotes EMT in Glioma via the miR-661/RAB3D Axis.

Background: Glioma is the most common malignant tumor of the central nervous system, and often displays invasive growth. Recently, circular RNA (circRNA), which is a novel non-coding type of RNA, has been shown to play a vital role in glioma tumorigenesis. However, the functions and mechanism of lipocalin-2 (Lcn2)-derived circular RNA (hsa_circ_0088732) in glioma progression remain unclear. Methods: We evaluated hsa_circ_0088732 expression by fluorescence in situ hybridization (FISH), Sanger sequencing, and PCR assays. Cell apoptosis was evaluated by flow cytometry and Hoechst 33258 staining. Transwell migration and invasion assays were performed to measure cell metastasis and viability. In addition, the target miRNA of hsa_circ_0088732 and the target gene of miR-661 were predicted by a bioinformatics analysis, and the interactions were verified by dual-luciferase reporter assays. RAB3D expression was analyzed by an immunochemistry assay, and E-cadherin, N-cadherin, and vimentin protein expression were examined by western blot assays. A mouse xenograft model was developed and used to analyze the effects of hsa_circ_0088732 on glioma growth in vivo. Results: We verified that hsa_circ_0088732 is circular and highly expressed in glioma tissues. Knockdown of hsa_circ_0088732 induced glioma cell apoptosis and inhibited glioma cell migration, invasion, and epithelial-mesenchymal transition (EMT). We found that hsa_circ_0088732 negatively regulated miR-661 by targeting miR-661, and RAB3D was a target gene of miR-661. In addition, inhibition of miR-661 promoted glioma cell metastasis and suppressed cell apoptosis. Knockdown of RAB3D induced cell apoptosis and suppressed cell metastasis. Moreover, hsa_circ_0088732 accelerated glioma progression through its effects on the miR-661/RAB3D axis. Finally, results from a mouse xenograft model confirmed that knockdown of hsa_circ_0088732 induced miR-661 expression, resulting in suppression of RAB3D expression and inhibition of tumor growth in vivo. Conclusion: We demonstrated that hsa_circ_0088732 facilitated glioma progression by sponging miR-661 to increase RAB3D expression. This study provides a theoretical basis for understanding the development and occurrence of glioma, as well as for the development of targeted drugs.

Investigating miRNA-661 and ATG4-B mRNA expression as potential biomarkers for hepatocellular carcinoma.

AIM: We aimed to examine the statistical association between serum expression of miRNA 661 (miR-661) and ATG-4B mRNA and hepatocellular carcinoma (HCC) based on in silico data analysis followed by clinical validation. PATIENTS & METHODS: Quantitative reverse-transcriptase real-time PCR was used to examine the expression of miR-661 and ATG-4B mRNA in the sera of HCC patients versus control. RESULTS: The expression of miR-661 and ATG-4B mRNA was positive in 97.14 and 77.14%, respectively, in HCC patients. The survival analysis showed that ATG-4B mRNA was an independent prognostic factor. CONCLUSION: Our data are the first report of its kind regarding the considerable clinical significance of miR-661 and ATG-4B mRNA in HCC patients.

Human Blastocyst Secreted microRNA Regulate Endometrial Epithelial Cell Adhesion.

Successful embryo implantation requires synchronous development and communication between the blastocyst and the endometrium, however the mechanisms of communication in humans are virtually unknown. Recent studies have revealed that microRNAs (miRs) are present in bodily fluids and secreted by cells in culture. We have identified that human blastocysts differentially secrete miRs in a pattern associated with their implantation outcome. miR-661 was the most highly expressed miR in blastocyst culture media (BCM) from blastocysts that failed to implant (non-implanted) compared to blastocysts that implanted (implanted). Our results indicate a possible role for Argonaute 1 in the transport of miR-661 in non-implanted BCM and taken up by primary human endometrial epithelial cells (HEECs). miR-661 uptake by HEEC reduced trophoblast cell line spheroid attachment to HEEC via PVRL1. Our results suggest that human blastocysts alter the endometrial epithelial adhesion, the initiating event of implantation, via the secretion of miR, abnormalities in which result in implantation failure.