LncRNA-SNX17 Promotes HTR-8/SVneo Proliferation and Invasion Through miR-517a/IGF-1 in the Placenta of Diabetic Macrosomia.

Gestational diabetes mellitus (GDM) has become a worldwide problem in recent years. Macrosomia, a primary consequence of GDM, has short-term and life-long consequences in the offspring of mothers with GDM. Our previous study showed that miR-517a was dysregulated in placenta and plasma of fetal growth restriction through inhibiting invasion of trophoblast and might be closely related with the regulation of birth weight by the placenta. To further investigate the mechanism of miR-517a, we conducted genome-wide microarray profile of lncRNAs. lncRNA-SNX17 was found to be significantly upregulated in the placenta of diabetic macrosomia by qRT-PCR, and the expression of miR-517a and IGF-1 were measured by qRT-PCR and Western blot. Interestingly, significant inverse correlations of the miR-517a with both lncRNA-SNX17 and IGF-1 expression were revealed in the placenta of diabetic macrosomia. Bioinformatic prediction also revealed that both lncRNA-SNX17 and IGF-1 possessed binding sites for miR-517a, which were then confirmed by luciferase report assay. LncRNA-SNX17 overexpression reduced the expression of miR-517a and increased the IGF-1 expression in HTR-8/SVneo human trophoblast cell line and thus enhanced the proliferation of HTR-8/SVneo. The enhancement of HTR-8/SVneo proliferation by lncRNA-SXN17 could be nullified by co-transfection of miR-517a mimics. The data suggested that lncRNA-SNX17 might promote the trophoblast proliferation through miR-517a/IGF-1 pathway and might play a role in the placentation of diabetic macrosomia.

Differential expression of Hsa-miR-517a/b in placental tissue may contribute to the pathogenesis of preeclampsia

Objective: Preeclampsia (PE) is a pregnancy hypertensive disorder that affects both maternal and fetal health. Many studies have investigated possible mechanisms in the pathogenesis of PE although the role of the placenta is undeniable. Evaluation of placental-specific microRNAs may provide additional data about the pathogenic mechanism of PE. This study compared the expression levels of Hsa-miR-517a/b in placental tissues obtained from PE patients and healthy controls. Material and Methods: One hundred tissues were obtained from fetal and maternal sides of the placenta of PE patients and healthy controls. Expression analysis was performed using quantitative real-time polymerase chain reaction. Results: Hsa-miR-517a/b level was significantly decreased in PE compared to controls (expression ratio: 0.40; p=0.007). Down-regulation of Hsa-miR-517a/b was also detected in fetal-side placental samples when compared to maternal-side in PE (expression ratio: 0.33; p=0.04). Furthermore, decreased expression of Hsa-miR-517a/b was detected in fetal-side tissue from PE cases compared to fetal-side samples from healthy pregnancies (expression ratio: 0.36; p=0.03). In maternal-side placental samples the expression level did not differ between PE and healthy pregnancies (p=0.1). Conclusion: These results demonstrate a differential expression of Hsa-miR-517a/b within placentas in pregnancies affected by PE and between placentas from PE and healthy pregnancies. Further studies are required to investigate a possible role for Hsa-miR-517a/b in the pathogenesis of PE.

Unc-13 homolog D mediates an antiviral effect of the chromosome 19 microRNA cluster miR-517a.

The function of microRNAs (miRNAs) can be cell autonomous or communicated to other cell types and has been implicated in diverse biological processes. We previously demonstrated that miR-517a-3p (miR-517a), a highly expressed member of the chromosome 19 miRNA cluster (C19MC) that is transcribed almost exclusively in human trophoblasts, attenuates viral replication via induction of autophagy in non-trophoblastic recipient cells. However, the molecular mechanisms underlying these effects remain unknown. Here, we identified unc-13 homolog D (UNC13D) as a direct, autophagy-related gene target of miR-517a, leading to repression of UNC13D. In line with the antiviral activity of miR-517a, silencing UNC13D suppressed replication of vesicular stomatitis virus (VSV), whereas overexpression of UNC13D increased VSV levels, suggesting a role for UNC13D silencing in the antiviral activity of miR-517a. We also found that miR-517a activated NF-κB signaling in HEK-293XL cells expressing TLR8, but the effect was not specific to C19MC miRNA. Taken together, our results define mechanistic pathways that link C19MC miRNA with inhibition of viral replication.

miRNA target identification and prediction as a function of time in gene expression data.

The understanding of miRNA target interactions is still limited due to conflicting data and the fact that high-quality validation of targets is a time-consuming process. Faster methods like high-throughput screens and bioinformatics predictions are employed but suffer from several problems. One of these, namely the potential occurrence of downstream (i.e. secondary) effects in high-throughput screens has been only little discussed so far. However, such effects limit usage for both the identification of interactions and for the training of bioinformatics tools. In order to analyse this problem more closely, we performed time-dependent microarray screening experiments overexpressing human miR-517a-3p, and, together with published time-dependent datasets of human miR-17-5p, miR-135b and miR-124 overexpression, we analysed the dynamics of deregulated genes. We show that the number of deregulated targets increases over time, whereas seed sequence content and performance of several miRNA target prediction algorithms actually decrease over time. Bioinformatics recognition success of validated miR-17 targets was comparable to that of data gained only 12 h post-transfection. We therefore argue that the timing of microarray experiments is of critical importance for detecting direct targets with high confidence and for the usability of these data for the training of bioinformatics prediction tools.

miR-517a is up-regulated in glioma and promotes glioma tumorigenesis in vitro and in vivo.

miR-517a has been reported to act as an oncogenic miRNA in human hepatocellular carcinoma and lung cancer. However, the roles and underlying molecular mechanism of miR-517a in glioma remain unclear. In the present study, the expression of miR-517a in clinical glioma tissues and glioma cell lines was examined by quantitative real-time PCR (qRT-PCR). Transfected with knockdown or forced expression of miR-517a, the effects of miR-517a on cell proliferation, migration, and invasion were detected through in vitro and in vivo tumorigenesis assays. Here, we report that miR-517a expression was up-regulated in glioma tissues when compared with normal brain tissues, and up-regulation of miR-517a level is tightly correlated with the status of pathology classification of glioma. A functional assay found that overexpression of miR-517a in glioma cells markedly promoted or suppressed cell proliferation, colony formation, migration and invasion, respectively. Moreover, we revealed that the knockdown of miR-517a dramatically suppressed glioma cell growth, migration, and invasion in vitro and in vivo Furthermore, we found that knockdown of miR-517a significantly induced apoptosis. Therefore, miR-517a acts an oncogenic miRNA that promotes tumor progression in glioma, and thus may become a promising therapeutic candidate for glioma.

miR-517a promotes Warburg effect in HCC by directly targeting FBP1.

PURPOSE: Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies worldwide. Our aim is to explore the expression and biological function of miR-517a in HCC. MATERIALS AND METHODS: We performed qRT-PCR to detect the expression of miR-517a in clinical samples and cell lines. CKK-8 assay and colony formation assay were employed to detect the miR-517a regulated cell proliferation. Glucose uptake and lactate production were examined to determine the Warburg effect. We also performed ECAR assay using Seahorse system. Luciferase acitivy assay was used to examine the binding of FBP1 3'UTR by miR-517a. RESULTS: miR-517a was upregulated in HCC samples in both genomic and mRNA levels. Moreover, overexpression of miR-517a promoted cell proliferation and Warburg effect. Mechanically, miR-517a could directly target the 3'-UTR of FBP1. In addition, restoring the expression of FBP1 inhibited cell growth. CONCLUSION: We demonstrated that miR-517a acts as an oncogene to promote Warburg effect in HCC, favoring tumor growth, and miR-517a/FBP1 could be a novel target for HCC treatment.

miR-517a is an independent prognostic marker and contributes to cell migration and invasion in human colorectal cancer.

Colorectal cancer (CRC) is a highly invasive tumor that is frequently associated with distant metastasis, which is the primary cause of poor prognosis. However, the mechanisms of metastasis remain poorly understood. MicroRNAs (miRNAs/miRs) have been considered to be implicated in CRC progression. In particular, miR-517a is proposed as a novel tumor-associated miRNA and has a potential role in tumor metastasis. The expression of miR-517a in CRC specimens was detected by reverse transcription-quantitative polymerase chain reaction. Transwell assays were performed to determine the migration and invasion of CRC cells. The putative target genes of miR-517a were disclosed using publicly available databases and western blot analysis. The present study identified that the expression of miR-517a was significantly higher in CRC tissues as compared with adjacent non-tumor tissues. Clinical analysis indicated that increased expression of miR-517a was correlated with poor prognostic features and poor long-term survival of CRC patients. In vitro evidences demonstrated that downregulation of miR-517a inhibited cell migration and invasion in HCT-116 cells. By contrast, upregulation of miR-517a increased the number of migrated and invaded SW480 cells. Notably, miR-517a expression was inversely regulated by forkhead box J3 (FOXJ3) abundance in CRC cells. Furthermore, an inverse correlation between miR-517a and FOXJ3 expression was observed in CRC tissues. In conclusion, miR-517a appears to be an independent prognostic marker for predicting survival of CRC patients, and may promote cell migration and invasion by inhibiting FOXJ3.

MiR-517a-3p accelerates lung cancer cell proliferation and invasion through inhibiting FOXJ3 expression.

AIMS: Aberrant expression of microRNAs (miRNAs) results in alterations of various biological processes (e.g., cell cycle, cell differentiation, and apoptosis) and cell transformation. Altered miRNAs expression was associated with lung carcinogenesis and tumor progression. This study aimed to investigate the function and underlying molecular events of miR-517a-3p on regulation of lung cancer cell proliferation and invasion. MAIN METHODS: Transfected miR-517a-3p mimics or inhibitors into 95D and 95C cells respectively, the effects of miR-517a-3p on lung cancer cell proliferation, migration, and invasion were detected. Bioinformatics software forecasted potential target genes of miR-517a-3p and dual luciferase reporter gene system and western blot verified whether miR-517a-3p regulates FOXJ3 expression directly. KEY FINDINGS: MiR-517a-3p was differentially expressed in lung cancer 95D and 95C cell lines that have different metastatic potential. Manipulation of miR-517a-3p expression changed lung cancer cell proliferation, migration and invasion capacity. MiR-517a-3p directly regulated FOXJ3 expression by binding to FOXJ3 promoter. SIGNIFICANCE: This study demonstrated that miR-517a-3p promoted lung cancer cell proliferation and invasion by targeting of FOXJ3 expression.