Oncogenic Role of MicroRNA-30b-5p in Glioblastoma Through Targeting Proline-Rich Transmembrane Protein 2

The 'dispanins' and related proteins in physiology and neurological disease

The dispanins are a family of 15 transmembrane proteins that have diverse and often unclear physiological functions. Many dispanins, including synapse differentiation induced gene 1 (SynDIG1), proline-rich transmembrane protein 1 (PRRT1)/SynDIG4, and PRRT2, are expressed in the central nervous system (CNS), where they are involved in the development of synapses, regulation of neurotransmitter release, and interactions with ion channels, including AMPA receptors (AMPARs). Others, including transmembrane protein 233 (TMEM233) and trafficking regulator of GLUT4-1 (TRARG1), are expressed in the peripheral nervous system (PNS); however, the function of these dispanins is less clear. Recently, a family of neurotoxins isolated from the giant Australian stinging tree was shown to target TMEM233 to modulate the function of voltage-gated sodium (NaV) channels, suggesting that the dispanins are inherently druggable. Here, we review current knowledge about the structure and function of the dispanins, in particular TMEM233 and its two most closely related homologs PRRT2 and TRARG1, which may be drug targets involved in neurological disease.

Development of a 3-MicroRNA Signature and Nomogram for Predicting the Survival of Patients with Uveal Melanoma Based on TCGA and GEO Databases

Background. The aim of this study was to apply bioinformatic analysis to develop a robust miRNA signature and construct a nomogram model in uveal melanoma (UM) to improve prognosis prediction. Methods. miRNA and mRNA sequencing data for 80 UM patients were obtained from The Cancer Genome Atlas (TCGA) database. The patients were further randomly assigned to a training set (n = 40, used to identify key miRNAs) and a testing set (n = 40, used to internally verify the signature). Then, miRNAs data of GSE84976 and GSE68828 were downloaded from Gene Expression Omnibus (GEO) database for outside verification. Combining univariate analysis and LASSO methods for identifying a robust miRNA biomarker in training set and the signature was validated in testing set and outside dataset. A prognostic nomogram was constructed and combined with decision curve as well as reduction curve analyses to assess the application of clinical usefulness. Finally, we constructed a miRNA-mRNA regulator network in UM and conducted pathway enrichment analysis according to the mRNAs in the network. Results. In total, a 3-miRNA was identified and validated that can robustly predict UM patients’ survival. According to univariate and multivariate cox analyses, age at diagnosis, tumor node metastasis (TNM) classification, stage, and the 3-miRNA signature significantly correlated with the survival outcomes. These characteristics were used to establish nomogram. The nomogram worked well for predicting 1 and 3 years of overall survival time. The decision curve of nomogram revealed a good clinical usefulness of our nomogram. What’s more, a miRNA-mRNA network was constructed. Pathway enrichment showed that this network was largely involved in mRNA processing, the mRNA surveillance pathway, the spliceosome, and so on. Conclusions. We developed a 3-miRNA biomarker and constructed a prognostic nomogram, which may afford a quantitative tool for predicting the survival of UM. Our finding also provided some new potential targets for the treatment of UM.

Regulation of miR-30b in cancer development, apoptosis, and drug resistance

miR-30b, which is encoded by the gene located on chromosome 8q24.22, plays an important role in a variety of diseases. In most types of tumors, miR-30b significantly inhibits the proliferation, migration, and invasion of cancer cells through the regulation of target genes. Moreover, miR-30b can inhibit the PI3K/AKT signaling pathway through the regulation of EGFR, AKT, Derlin-1, GNA13, SIX1, and other target genes, thus inhibiting the EMT process of tumor cells and promoting apoptosis. In addition, miR-30 plays a significant role in alleviating drug resistance in tumor cells. Although the use of miR-30b as a clinical diagnostic indicator or anticancer drug is still facing great difficulties in the short term, with the deepening of research, the potential application of miR-30b is emerging.

Use of signals of positive and negative selection to distinguish cancer genes and passenger genes

A major goal of cancer genomics is to identify all genes that play critical roles in carcinogenesis. Most approaches focused on genes positively selected for mutations that drive carcinogenesis and neglected the role of negative selection. Some studies have actually concluded that negative selection has no role in cancer evolution. We have re-examined the role of negative selection in tumor evolution through the analysis of the patterns of somatic mutations affecting the coding sequences of human genes. Our analyses have confirmed that tumor suppressor genes are positively selected for inactivating mutations, oncogenes, however, were found to display signals of both negative selection for inactivating mutations and positive selection for activating mutations. Significantly, we have identified numerous human genes that show signs of strong negative selection during tumor evolution, suggesting that their functional integrity is essential for the growth and survival of tumor cells.

Roles and regulatory mechanisms of miR-30b in cancer, cardiovascular disease, and metabolic disorders (Review)

MicroRNAs (miRNAs) are non-coding RNAs 21-23 nucleotides in length that regulate gene expression, and thereby modulate signaling pathways and protein synthesis in both physiological and pathogenic processes. miR-30b inhibits cell proliferation, migration, invasion and epithelial-mesenchymal transformation in multiple types of cancer. In addition to its role in several types of neoplasias, miR-30b has been shown to exhibit essential roles in cardiovascular and metabolic diseases. In the present review, an overview of the biological functions of miR-30b and its role in the pathogenesis of neoplastic, cardiovascular and metabolic diseases is provided. miR-30b is a potential candidate for clinical development as a diagnostic and prognostic biomarker, therapeutic agent and drug target. However, further research is required to elucidate its role in health and disease and to harness its potential clinical utility.

lncRNA CTBP1-AS2 promotes proliferation and migration of glioma by modulating miR-370-3p-Wnt7a-mediated epithelial-mesenchymal transition

Glioma is one of the most common and aggressive malignant primary brain tumors, with a poor 5-year survival rate. The long noncoding RNA (lncRNA) CTBP1-AS2 has been shown to be correlated with the prognosis of cancer, but the role of CTBP1-AS2 in glioma and its concrete mechanism is fully unknown. The clinical data and tissues of glioma patients were analyzed. Cell viability and migration assays were performed. Western blotting and qRT-PCR were adopted for investigation of target protein expressions. Double luciferase assay was used to investigate the interaction between different elements. The lncRNA CTBP1-AS2 had increased expression profiles in tumor tissues, which is associated with poor prognosis. In detail, CTBP1-AS2 knockdown decreased proliferation and migration phenotypes in both U87-MG and LN229 cells. Moreover, CTBP1-AS2 knockdown suppressed the key epithelial-mesenchymal transition (EMT) markers by downregulating Wnt7a-mediated signaling. Furthermore, miR-370-3p functioned as a link that could be absorbed by CTBP1-AS2, thus regulating Wnt7a expression. Lastly, the CTBP1-AS2-miR-370-3p-Wnt7a axis modulated EMT in glioma cells in vitro and in vivo. This study provides new insights that a novel lncRNA, CTBP1-AS2, regulates EMT of glioma by modulating the miR-370-3p-Wnt7a axis.

Proline-rich transmembrane protein 2 (PRRT2) regulates the actin cytoskeleton during synaptogenesis

Mutations in proline-rich transmembrane protein 2 (PRRT2) have been recently identified as the leading cause of a clinically heterogeneous group of neurological disorders sharing a paroxysmal nature, including paroxysmal kinesigenic dyskinesia and benign familial infantile seizures. To date, studies aimed at understanding its physiological functions in neurons have mainly focused on its ability to regulate neurotransmitter release and neuronal excitability. Here, we show that PRRT2 expression in non-neuronal cell lines inhibits cell motility and focal adhesion turnover, increases cell aggregation propensity, and promotes the protrusion of filopodia, all processes impinging on the actin cytoskeleton. In primary hippocampal neurons, PRRT2 silencing affects the synaptic content of filamentous actin and perturbs actin dynamics. This is accompanied by defects in the density and maturation of dendritic spines. We identified cofilin, an actin-binding protein abundantly expressed at the synaptic level, as the ultimate effector of PRRT2. Indeed, PRRT2 silencing unbalances cofilin activity leading to the formation of cofilin-actin rods along neurites. The expression of a cofilin phospho-mimetic mutant (cof-S3E) is able to rescue PRRT2-dependent defects in synapse density, spine number and morphology, but not the alterations observed in neurotransmitter release. Our data support a novel function of PRRT2 in the regulation of the synaptic actin cytoskeleton and in the formation of synaptic contacts.

Exosomal release of microRNA-454 by breast cancer cells sustains biological properties of cancer stem cells via the PRRT2/Wnt axis in ovarian cancer

AIMS

Cancer-derived exosomes carrying tumor-derived molecules such as miRNAs and proteins related to various phenotypes have been detected in both the bloodstream and other biofluids of patients with different cancers. Thus, our main purpose here was to determine the role of the exosomal microRNA-454 (miR-454) derived by MDA-MB-231 in self-renewal of cancer stem cells (CSCs) in ovarian cancer (OC).

MATERIALS AND METHODS

Extraction of MDA-MB-231 cells-derived exosomes (231-derived exosomes) was conducted to treat CD44+/CD133+ SKOV3 and CoC1 cells to observe cell growth and stemness. Next, the differentially expressed miRNAs in SKOV3 cells after exosome treatment were filtered using microarray analysis. Subsequently, the cell viability was detected after reducing the exosomal miR-454 and the addition of a Wnt pathway inhibitor C59. Finally, the pro-tumorigenic function of exosomes on OC cells in vivo was investigated.

KEY FINDINGS

After co-culture with 231-derived exosomes, the stemness of CSCs were promoted. Subsequently, the reduction of exosomal miR-454 weakened the roles of exosomes on cell stemness. Proline-rich transmembrane protein 2 (PRRT2) was substantiated as a target gene of miR-454 in SKOV3 and CoC1 cells. C59 reversed the repressive role of exosomes in stemness of CSCs. When being evaluated in a mouse model, exosomal miR-454 led to an efficacious effect in suppressing the tumor weight and volume in vivo.

SIGNIFICANCE

Altogether, 231-derived exosomes carrying miR-454 disrupted the Wnt pathway by targeting PRRT2, thereby promoting CSC stemness in vitro and OC cell growth in vivo.

Recent advances of the regulation roles of MicroRNA in glioblastoma

Glioblastoma (GBM) is one of the most malignant neural tumors, and patients with GBM often die soon after the onset. The pathogenesis of GBM is very complicated, and there is no effective treatment for GBM. The current research results show that a variety of microRNA (miRNA) are involved in the regulation of GBM occurrence and development through specific signal pathways. Meanwhile, as a non-invasive biological indicator, there is an important clinical value of miRNA in the diagnosis and prognosis of GBM. The research of targeted miRNA treatment for GBM is still in the cell and animal model stage, although the basic research shows a good result, there is still a certain distance to the clinical application.

Identification and Analysis of Glioblastoma Biomarkers Based on Single Cell Sequencing

Glioblastoma (GBM) is one of the most common and aggressive primary adult brain tumors. Tumor heterogeneity poses a great challenge to the treatment of GBM, which is determined by both heterogeneous GBM cells and a complex tumor microenvironment. Single-cell RNA sequencing (scRNA-seq) enables the transcriptomes of great deal of individual cells to be assayed in an unbiased manner and has been applied in head and neck cancer, breast cancer, blood disease, and so on. In this study, based on the scRNA-seq results of infiltrating neoplastic cells in GBM, computational methods were applied to screen core biomarkers that can distinguish the discrepancy between GBM tumor and pericarcinomatous environment. The gene expression profiles of GBM from 2343 tumor cells and 1246 periphery cells were analyzed by maximum relevance minimum redundancy (mRMR). Upon further analysis of the feature lists yielded by the mRMR method, 31 important genes were extracted that may be essential biomarkers for GBM tumor cells. Besides, an optimal classification model using a support vector machine (SVM) algorithm as the classifier was also built. Our results provided insights of GBM mechanisms and may be useful for GBM diagnosis and therapy.

Down-regulation of miR-30b-5p protects cardiomyocytes against hypoxia-induced injury by targeting Aven

Background

Ischemia/hypoxia-induced cardiomyocyte apoptosis has been considered as a main cause of myocardial infarction. Here, we aimed to investigate the functional role of miR-30b-5p in hypoxic cardiomyocytes.

Methods

AC16 human cardiomyocytes were cultured under hypoxia to simulate myocardial infarction. A qRT-PCR assay was performed to determine miR-30b-5p expression in hypoxic cardiomyocytes. Cell survival, injury and apoptosis were assessed by MTT, lactate dehydrogenase (LDH) release, and flow cytometry assays, respectively. The target gene of miR-30b-5p in hypoxic cardiomyocytes was validated by luciferase reporter assay and Western blotting.

Results

MiR-30b-5p expression was found to be significantly upregulated in hypoxic AC16 cells. The in vitro experiments showed that downregulation of miR-30b-5p effectively alleviated hypoxia-induced cardiomyocyte injury. Furthermore, Aven is a potential target gene of miR-30b-5p and its downregulation could partially reverse the influence of miR-30b-5p knockdown on AC16 cells under hypoxia.

Conclusions

Inhibition of miR-30b-5p could protect cardiomyocytes against hypoxia-induced injury by targeting Aven.

A 3-miRNA signature predicts survival of patients with hypopharyngeal squamous cell carcinoma after post-operative radiotherapy

Since the prognosis of hypopharyngeal squamous cell carcinoma (HSCC) remains poor, identification of miRNA as a potential prognostic biomarker for HSCC may help improve personalized therapy. In the 2 cohorts with a total of 511 patients with HSCC (discovery: N = 372 and validation: N = 139) after post-operative radiotherapy, we used miRNA microarray and qRT-PCR to screen out the significant miRNAs which might predict survival. Associations of miRNAs and the signature score of these miRNAs with survival were performed by Kaplan-Meier survival analysis and multivariate Cox hazard model. Among 9 candidate, miRNAs, miR-200a-3p, miR-30b-5p, miR-3161, miR-3605-5p, miR-378b and miR-4451 were up-regulated, while miR-200c-3p, miR-429 and miR-4701 were down-regulated after validation. Moreover, the patients with high expression of miR-200a-3p, miR-30b-5p and miR-4451 had significantly worse overall survival (OS) and disease-specific survival (DSS) than did those with low expression (log-rank P < .05). Patients with a high-risk score had significant worse OS and DSS than those with low-risk score. Finally, after adjusting for other important prognostic confounders, patients with high expression of miR-200a-3p, miR-30b-5p and miR-4451 had significantly high risk of overall death and death owing to HSCC and patients with a high-risk score has approximately 2-fold increased risk in overall death and death owing to HSCC compared with those with a low-risk score. These findings indicated that the 3-miRNA-based signature may be a novel independent prognostic biomarker for patients given surgery and post-operative radiotherapy, supporting that these miRNAs may jointly predict survival of HSCC.

Positive feedback loop of lncRNA HOXC-AS2/miR-876-5p/ZEB1 to regulate EMT in glioma

Purpose

Growing evidence has valued the diagnostic and therapeutic ability of long non-coding RNAs (lncRNAs) in various human tumors including glioma. Here, we investigated the biological function and potential mechanism of a novel cancer-related lncRNA, HOXC-AS2, in glioma.

Materials and methods

The expression of lncHOXC-AS2 was detected using qRT-PCR in glioma cells and tissues. A series of in vitro studies were performed to analyze the biological function of lncHOXC-AS2. Dual-luciferase reporter, RIP was used to determine the relation between lncHOXC-AS2, miR-876-5p and ZEB1. CHIP assay was performed to investigate the transcriptional regulation of HOXC-AS2.

Results

We found HOXC-AS2 was upregulated in glioma cells and tissues. Depletion of HOXC-AS2 was associated with the inhibition of migration, invasion and EMT process in glioma cells. Mechanism, HOXC-AS2 can sponge miR-876-5p to affect ZEB1 expression. Meanwhile, ZEB1 can bind promoter region of HOXC-AS2 and regulate HOXC-AS2 at transcriptional level.

Conclusion

Our results conclude that HOXC-AS2/miR-876-5p/ZEB1 constitutes a positive feedback loop to regulate EMT in GBM, providing a potential therapeutic target for glioma.

Down-regulated microRNA-30b-3p inhibits proliferation, invasion and migration of glioma cells via inactivation of the AKT signaling pathway by up-regulating RECK

microRNAs (miRNAs) have been found to affect various cancers, and expression of numerous miRNAs is revealed in glioma. However, the role of microRNA-30b-3p (miR-30b-3p) in glioma remains elusive. Therefore, the present study aims to explore the specific mechanism by which miR-30b-3p influence the development of glioma in relation to the AKT signaling pathway. First, glioma cell lines were collected with miR-30b-3p and reversion-inducing cysteine-rich protein with kazal motifs (RECK) expression measured. The functional role of miR-30b-3p and RECK in glioma was determined via gain- and loss-of-function approaches. Subsequently, the expression of invasion- and migration-related factors (MMP-2 and MMP-9) and the AKT signaling pathway-related factors (AKT, p-AKT and PI3K-p85) was detected. Moreover, in vivo experiments were also conducted to investigate how miR-30b-3p influences in vivo tumorigenesis. The results showed that miR-30b-3p was up-regulated and RECK was down-regulated in glioma. RECK was a target gene of miR-30b-3p. Decreased miR-30b-3p and overexpressed RECK led to decreased expression of MMP-2, MMP-9 and p-AKT. Overexpressed RECK and LY294002 could decrease p-AKT and PI3K-p85 expression accompanied with unchanged expression of total protein of AKT. Additionally, proliferation, migration and invasion of glioma cells and tumor formation in nude mice were repressed owing to reduced expression of miR-30b-3p or elevated expression of RECK. In summary, miR-30b-3p inhibition suppresses metastasis of glioma cells by inactivating the AKT signaling pathway via RECK up-regulation, providing a new target for glioma treatment.

miR-25-3p promotes glioma cell proliferation and migration by targeting FBXW7 and DKK3

MicroRNAs (miRs) serve important roles in glioma. However, the underlying molecular mechanism of miR-25 in glioma progression remains largely unknown; therefore, it was investigated in the present study. RT-qPCR analysis revealed that miR-25 expression levels were markedly increased in human glioma tissue and glioma cell lines compared with normal brain tissues and normal human astrocytes, respectively. miR-25 upregulation exhibited an association with glioma progression, and the knockdown of miR-25 significantly inhibited glioma cell proliferation and migration. F-box and WD repeat domain containing 7 (FBXW7) and dickkopf WNT signaling pathway inhibitor 3 (DKK3) were identified as target genes of miR-25. FBXW7 and DKK3 expression levels were significantly downregulated in glioma tissue samples compared with normal brain tissue, and their expression levels were negatively regulated by miR-25 expression in glioma cells. Furthermore, inhibition of FBXW7 and DKK3 expression suppressed the miR-25-induced effects on glioma cell proliferation and migration. The findings of the present study suggest that miR-25 may promote glioma cell proliferation and migration by inhibiting the expression of FBXW7 and DKK3. Therefore, miR-25 may serve as a promising molecular target for the treatment of glioma.

Semaphorin 3A Contributes to Secondary Blood-Brain Barrier Damage After Traumatic Brain Injury

Semaphorin 3A (SEMA3A) is a member of the Semaphorins family, a class of membrane-associated protein that participates in the construction of nerve networks. SEMA3A has been reported to affect vascular permeability previously, but its influence in traumatic brain injury (TBI) is still unknown. To investigate the effects of SEMA3A, we used a mouse TBI model with a controlled cortical impact (CCI) device and a blood–brain barrier (BBB) injury model in vitro with oxygen-glucose deprivation (OGD). We tested post-TBI changes in SEMA3A, and its related receptors (Nrp-1 and plexin-A1) expression and distribution through western blotting and double-immunofluorescence staining, respectively. Neurological outcomes were evaluated by modified neurological severity scores (mNSSs) and beam-walking test. We examined BBB damage through Evans Blue dye extravasation, brain water content, and western blotting for VE-cadherin and p-VE-cadherin in vivo, and we examined the endothelial cell barrier through hopping probe ion conductance microscopy (HPICM), transwell leakage, and western blotting for VE-cadherin and p-VE-cadherin in vitro. Changes in miR-30b-5p were assessed by RT-PCR. Finally, the neuroprotective function of miR-30b-5p is measured by brain water content, mNSSs and beam-walking test. SEMA3A expression varied following TBI and peaked on the third day which expressed approximate fourfold increase compared with sham group, with the protein concentrated at the lesion boundary. SEMA3A contributed to neurological function deficits and secondary BBB damage in vivo. Our results demonstrated that SEMA3A level following OGD injury almost doubled than control group, and the negative effects of OGD injury can be improved by blocking SEMA3A expression. Furthermore, the expression of miR-30b-5p decreased approximate 40% at the third day and 60% at the seventh day post-CCI. OGD injury also exhibited an effect to approximately decrease 50% of miR-30b-5p expression. Additionally, the expression of SEMA3A post-TBI is regulated by miR-30b-5p, and miR-30b-5p could improve neurological outcomes post-TBI efficiently. Our results demonstrate that SEMA3A is a significant factor in secondary BBB damage after TBI and can be abolished by miR-30b-5p, which represents a potential therapeutic target.

Knockdown of lncRNA-UCA1 inhibits the proliferation and migration of melanoma cells through modulating the miR-28-5p/HOXB3 axis

Long non-coding RNA urothelial carcinoma-associated 1 (UCA1) functions as an oncogene in different human cancers, including melanoma. However, the molecular mechanism of UCA1 underlying melanoma progression still remains largely unknown. In the present study, reverse transcription quantitative polymerase chain reaction and western blot analyses were used to examine the mRNA and protein expression levels, respectively. Cell Counting Kit-8 and wound healing assays were conducted to study cell proliferation and migration, respectively. A luciferase reporter assay was used to confirm the targeting relationship. It was demonstrated that UCA1 expression was increased in melanoma tissues and cell lines. In addition, UCA1 expression was higher in melanoma tissues at stage III-IV than in tissues at stage I-II. Inhibition of UCA1 expression markedly reduced melanoma cell proliferation and migration. Further investigation revealed that UCA1 functioned in melanoma cells through directly binding with microRNA (miR)-28-5p. The expression of miR-28-5p was significantly reduced in melanoma tissues and had an inverse correlation with UCA1 expression. In addition, miR-28-5p expression was higher in melanoma tissues at advanced stages than in stage I-II tissues. Furthermore, homeobox (HOX)B3 was identified as a target gene of miR-28-5p in melanoma cells, and HOXB3 overexpression reversed the suppressive effects of UCA1 downregulation on melanoma cell proliferation and migration. Finally, HOXB3 was upregulated in melanoma tissues compared with its expression in adjacent tissues, and HOXB3 expression was increased in melanoma tissues at advanced stages. Taken together, the regulatory network of the UCA1/miR-28-5p/HOXB3 axis in melanoma was demonstrated for the first time in the present study, expanding the understanding of the molecular mechanism underlying melanoma progression. Future studies may further confirm the function of this signaling pathway in vivo.

Long non-coding RNA TUG1 promotes osteosarcoma cell proliferation and invasion through inhibition of microRNA-212-3p expression

Taurine upregulated gene 1 (TUG1), a long non-coding RNA (lncRNA), has recently been suggested to be associated with the development of osteosarcoma (OS), but the underlying molecular mechanism still remains largely unclear. In the present study, it was revealed that TUG1 was significantly upregulated whereas miR-212-3p was significantly downregulated in OS tissues and cell lines, when compared with adjacent non-tumor tissues and normal osteoblasts cell lines, respectively. An inverse association between the TUG1 and miR-212-3p expression was also observed in OS tissues. Furthermore, TUG1 directly interacted with miR-212-3p and negatively regulated the expression of miR-212-3p in OS cells. In vitro experiments further indicated that inhibition of TUG1 suppressed the proliferation and invasion of OS cells. Furthermore, knockdown of miR-212-3p eliminated the suppressive effects of TUG1 inhibition on the proliferation and invasion of OS cells. Taken together, these findings demonstrate that TUG1 promotes OS cell proliferation and invasion by inhibition of miR-212-3p expression, thus suggesting that TUG1 may become a potential therapeutic target for OS.

Long non-coding RNA GAS5 inhibits ovarian cancer cell proliferation via the control of microRNA-21 and SPRY2 expression

In recent decades, numerous long non-coding (lnc)RNAs, including growth arrest-specific transcript 5 (GAS5), have been demonstrated to exert promoting or suppressive effects in human cancers. Decreased expression of the lncRNA GAS5 was reported to promote cell proliferation, migration and invasion and indicate poor prognosis in ovarian cancer. However, the exact underlying molecular mechanism through which GAS5 is involved in ovarian cancer growth remains unknown. The present study aimed to investigate the regulatory mechanism of GAS5 in ovarian cancer cell proliferation. Quantitative polymerase chain reaction and western blot analysis were used to examine RNA and protein expression, respectively. An MTT assay was used to examine cell proliferation. A luciferase reporter gene assay was conducted to verify the targeting relationship. It was identified that the expression levels of GAS5 and Sprouty homolog 2 (SPRY2) were significantly downregulated, while the expression level of microRNA (miR)-21 was significantly upregulated in ovarian cancer tissues and cell lines compared with adjacent non-tumor tissues and normal ovarian epithelial cells, respectively. Downregulation of GAS5 was significantly associated with advanced clinical stage. Luciferase assay data indicated that miR-21 was a direct target of GAS5 and that SPRY2 was a target gene of miR-21 in ovarian cancer-derived A2780 cells. GAS5 overexpression significantly inhibited the proliferation of ovarian cancer cells, which was accompanied by the downregulation of miR-21 and the upregulation of SPRY2. The overexpression of miR-21 caused a significant decrease in A2780 cell proliferation, which was accompanied by reduced SPRY2 expression. Furthermore, miR-21 overexpression attenuated the suppressive effects of GAS5 on A2780 cell proliferation and rescued the promoting effects of GAS5 on SPRY2 expression. In addition, the knockdown of SPRY2 also rescued the suppressive effects of GAS5 on the proliferation of A2780 cells. In summary, our study demonstrates that GAS5 exerts a suppressive effect on the proliferation of ovarian cancer cells, at least in part via the inhibition of miR-21 expression and subsequent increased SPRY2 expression. These findings suggest that the GAS5/miR-21/SPRY2 signaling pathway may be a potential therapeutic target in ovarian cancer.

Knockdown of RWD domain containing 3 inhibits the malignant phenotypes of glioblastoma cells via inhibition of phosphoinositide 3-kinase/protein kinase B signaling

Glioblastoma is the most common and malignant primary brain tumor. RWD domain containing 3 (RWDD3) has been previously reported to serve a promoting role in pituitary tumors. However, the exact role of RWDD3 in glioblastoma remains unclear. Therefore, the present study aimed to investigate the expression levels of RWDD3 in human glioblastoma tissues and cell lines, as well as to examine the regulatory mechanism of RWDD3 underlying glioblastoma growth and metastasis. The results revealed that RWDD3 was significantly upregulated in glioblastoma tissues compared with normal brain tissues, while high expression of RWDD3 was associated with a shorter survival time of glioblastoma patients. The expression levels of RWDD3 were also higher in the glioblastoma cell lines compared with the normal human astrocyte cell line. Subsequent to knockdown of RWDD3, the proliferation of glioblastoma U87 and U251 cells was significantly decreased, possibly due to the cell cycle arrest at G1 phase, as well as the increased cell apoptosis. Furthermore, downregulation of RWDD3 also suppressed U87 and U251 cell invasion by inhibiting the expression levels of matrix metalloproteinase 2 (MMP2) and MMP9. Molecular mechanism investigation demonstrated that knockdown of RWDD3 significantly downregulated the activity of the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathway. Activation of PI3K/AKT signaling prevented the suppressive effects of RWDD3 downregulation on glioblastoma cell proliferation and migration, concurrent with increased protein levels of MMP2 and MMP9. In conclusion, the current study demonstrated for the first time that inhibition of RWDD3 expression inhibited glioblastoma progression, at least partly, via suppressing the PI3K/AKT signaling activity, and thus RWDD3 may be a novel potential therapeutic target for glioblastoma.