Circ_CLIP2 promotes glioma progression through targeting the miR-195-5p/HMGB3 axis.

BACKGROUND: Circular RNA (circRNA) has been demonstrated to play key roles in regulating glioma progression. Understanding the regulatory mechanism of circRNA in glioma is vital to reveal the pathogenesis of glioma and develop novel therapeutic strategies. Therefore, our study focuses on the role and underlying mechanism of Circ_CLIP2 in glioma. METHODS: The expression of Circ_CLIP2, miR-195-5p and HMGB3 in glioma cells and tissues were analyzed using qRT-PCR. Cell proliferation was determined with colony formation and MTT assays. Cell cycle and apoptosis were examined by flow cytometry. Western blot was conducted for analyzing HMGB3, PCNA, Bax, Bcl-2, cleaved-caspase 3, Wnt-1 and ß-catenin. Dual-luciferase reporter assay was measured to investigate the interaction among Circ_CLIP2, miR-195-5p and HMGB3. RESULTS: The expression of Circ_CLIP2 and HMGB3 were increased while miR-195-5p was down-regulated in glioma cells and patients. Silencing of Circ_CLIP2 inhibited cell proliferation, enhanced cell apoptosis and inhibited the Wnt/ß-catenin signaling pathway. Circ_CLIP2 suppressed miR-195-5p expression by directly sponging miR-195-5p. MiR-195-5p inhibited HMGB3 expression via directly targeting HMGB3. Knockdown of miR-195-5p facilitated cell proliferation, inhibited cell apoptosis and activated Wnt/ß-catenin signaling, which were reversed by silencing of HMGB3. CONCLUSION: Knockdown of Circ_CLIP2 suppresses glioma progression by targeting miR-195-5p/HMGB3 thus inhibiting Wnt/ß-catenin signaling. This study may provide potential therapeutic targets against glioma.

[Retracted] MicroRNA-375 inhibits glioma cell proliferation and migration by downregulating RWDD3 in vitro.

The authors of the above article drew to our attention that, in the above paper, they had identified three instances of data overlapping between data panels, suggesting that data purportedly showing results obtained under different experimental conditions had been derived from the same original source. Comparing among the data panels, two pairs of panels in Fig. 4B were shown to be overlapping, and a further pair of panels showed overlapping data in Fig. 6B. The authors were presented with an opportunity to correct their figures in a Corrigendum, although it has subsequently come to light that the replacement figures themselves featured problems with overlapping data. Given the errors that have been identified in the compilation of the figures in this article, the Editor of Oncology Reports has decided that this article should be retracted from the publication owing to a lack of overall confidence in the presented data. The authors all agree to the retraction of this article, and the Editor and the authors apologize for any inconvenience that might result from this retraction. [the original article was published in Oncology Reports 39: 1825-1834, 2018; DOI: 10.3892/or.2018.6261].

[Corrigendum] MicroRNA-375 inhibits glioma cell proliferation and migration by downregulating RWDD3 in vitro.

The authors of the above article drew to our attention that they had identified three instances of data overlapping between data panels, suggesting that data purportedly showing results obtained under different experimental conditions had been derived from the same original source. Comparing between the two figures, two pairs of panels in Fig. 4B (the Mimics control and blank experiments for the U87 and U251 cell lines) were shown to be overlapping, and a further pair of panels showed overlapping data in Fig. 6B (the data panels for the miR­375 mi + .pCDNA/RWDD3 and miR­375 mi + .pCDNA experiments for the U87 cell line). The authors were able to re­examine the original data files and retrieve the correct data panels. The errors in these figures arose through inadvertently assembling Figs. 4 and 6 incorrectly. The revised versions of Figs. 4 and 6, featuring the corrected data panels for the Mimics control and blank experiments for the U87 and U251 cell lines in Fig. 4B, and the correct data for the U87 cell line in Fig. 6B, are shown opposite and on the next page, respectively. Note that the corrections to the data shown in these Figures do not affect the overall conclusions reported in the paper. The authors are grateful to the Editor of Oncology Reports for allowing them the opportunity to publish this Corrigendum, and apologize to the readership for any inconvenience caused. [the original article was published in Oncology Reports 39: 1825-1834, 2018; DOI: 10.3892/or.2018.6261].

MicroRNA-375 inhibits glioma cell proliferation and migration by downregulating RWDD3 in vitro.

Derived from brain glial cells, gliomas are currently the most common primary tumours in the central nervous system and are characterised by a high recurrence rate and poor prognosis. RWDD3 (RWD domain-containing sumoylation enhancer, also termed RSUME), which can be induced by cellular stress, such as CoCl2, heat shock and hypoxia, may play a crucial role in tumour angiogenesis, growth and metastasis. MicroRNAs (miRNAs) have been demonstrated to act as negative regulators of post-transcriptional gene expression and are involved in tumour growth and metastasis. In the present study, we explored the role of RWDD3 in glioma cell proliferation and invasion by the knockdown of RWDD3 with lentiviral shRNA and demonstrated that miRNA hsa-miR-375, regulates RWDD3 and has an important role in glioma progression. We found that expression of RWDD3 in high-grade gliomas was significantly higher than that noted in normal brain tissues and lower-grade gliomas in vivo. Knockdown of RWDD3 effectively led to cell cycle arrest, decreased proliferation and invasion, and increased apoptosis in human glioma cell lines. Furthermore, miR-375 was downregulated in human gliomas and overexpression of miR-375 caused downregulation of RWDD3 in glioma cells as well as inhibited their motility. Thus, these findings suggest that RWDD3 and miR-375 may function as therapeutic biomarkers for glioma patients.

Lentivirus­mediated knockdown of chondroitin polymerizing factor inhibits glioma cell growth in vitro.

Glioma is the most common primary tumor in the central nervous system, characterized by rapid progression, aggressive behavior, frequent recurrence and poor prognosis. In the present study we demonstrated that chondroitin polymerizing factor (CHPF) is highly expressed in human glioma tissues and 4 glioma cell lines. To explore the role of CHPF in glioma, a lentiviral vector expressing CHPF shRNA was constructed and transfected into the glioma U251 cells, which stably downregulated the expression levels of the CHPF gene in U251 cells in vitro. U251 cell proliferation inhibition rates were determined by MTT assay. The effect of survivin shRNA on U251 cell cycle distribution and cell apoptosis was determined by flow cytometry. Compared to the shRNA­Ctrl group of cells, the shRNA-CHPF group of cells exhibited decreased proliferation and a significant increase in the proportion of cells in the G0/G1 phase. In addition, we found that knockdown of the expression of CHPF increased apoptosis in glioma U251 cells. Therefore, our results confirmed that CHPF promotes growth and inhibits apoptosis in glioma U251 cells. Thus, by in vivo and in vitro data, the present study suggests that CHPF could be a new potential therapeutic target for glioma.

SNORD47, a box C/D snoRNA, suppresses tumorigenesis in glioblastoma.

SNORD47 is a member of the C/D box small nucleolar RNAs, which have been implicated in cancer development. We intended to investigate the therapeutic potential of SNORD47 in glioma. We found that the expression of SNORD47 was downregulated in glioma tissues samples and inversely associated with advanced tumor stage (WHO grade IV). Kaplan-Meier survival analysis revealed that glioma patients with high SNORD47 expression had longer overall survival than those with low SNORD47 expression. SNORD47 suppressed the proliferation of glioma cells and induced G2 phase arrest. In addition, upregulation of SNORD47 suppressed invasion and epithelial-mesenchymal transition in glioma cells, and combination treatment with lenti-SNORD47 could augment the anti-tumor effect of temozolomide. These results showed that SNORD47 acted as a tumor suppressor in glioma, and provided the potential anti-tumor function in glioma treatment.

Over-expression of LRIG1 suppresses biological function of pituitary adenoma via attenuation of PI3K/AKT and Ras/Raf/ERK pathways in vivo and in vitro.

Pituitary adenomas (PAs) are well known as a common intracranial benign tumor, and a portion of PAs are refractory to current therapeutic methods. ErbB receptors family signaling pathway regulates the expression of PAs activation associated gene. Inhibition of epidermal growth factor receptor (EGFR) can inhibit proliferation of PAs. Leucine-rich repeats and immunoglobulin-like domains protein 1 ( LRIG1), a negative mediated gene of ErbB receptors family, plays a role in many tumors. However, there are seldom researches about the functional role of LRIG1 in PAs. The aim of this study is to explore the potential effect of LRIG1 and its regulating mechanism in PAs. First, we investigated the role of LRIG1 in cell migration, invasion of PAs with transfected LRIG1 or control. Then, we explored its impact on cell proliferation and apoptosis of PAs in vivo. To study the regulating mechanism of LRIG1, we examined the expression of molecular factor of PI3K/AKT and Ras/Raf/ERK pathway using Western blotting in vitro and RT-PCR in vitro and in vivo. It was found that LRIG1 over-expression inhibited cell migration, invasion and proliferation, and promoted apoptosis of PAs in vivo and in vitro. Furthermore, LRIG1 suppressed the expression of signaling of PI3K/AKT and Ras/Raf/ERK pathways in PAs. LRIG1, as a negative mediated gene of tumor, can inhibit biological function of PAs via inhibiting PI3K/AKT and Ras/Raf/ERK pathways, and it might be a new target for gene therapy of PAs.