Retracted: LncRNA SNHG16 Promotes Proliferation,Migration,and Invasion of Glioma Cells Through Regulating the miR-490 / PCBP2 Axis

Abstract

Cancer Biotherapy and Radiopharmaceuticals

officially retracts the paper entitled, “LncRNA SNHG16 Promotes Proliferation, Migration, and Invasion of Glioma Cells Through Regulating the miR-490/PCBP2 Axis,” by Fangen Kong, Yang Yan, Jinfeng Deng, Yaoli Zhu, Yingqin Li, Huiqing Li, and Yiping Wang (Cancer Biother Radiopharm. E-pub ahead of print 23 Jul 2020; doi: 10.1089/cbr.2019.3535) at the authors' request:

“We apologized that we have found a serious problem in our paper. In fact, the Western blot experiment in our study was commissioned a third-party company for testing. In present, some peers have found that the company has forged experimental reports. After contacting the company, they were unable to provide the original images. We have checked and confirmed that the authenticity of the data provided by the company is problematic. In view of the problems in this paper, all the authors have discussed and agreed to withdraw the paper.”

[sic]

The journal publisher requested the name of the “third-party company,” to which the authors replied:

“We apologize for our mistakes. Our so-called “the third party company”, after further investigation, is actually not a company but an individual person. Due to the personal reasons, the previous experimental data were lost and the original raw data could not be provided. So we can not guarantee the authenticity of those data provided by that person. Some members are considering to repeat the experiment again, but we have no way to raise enough fund to repeat it. Hence after serious discussion, we decided to withdraw the manuscript.

Again we apologize sincerely for your inconvenience.”

[sic]

Submissions from a third party are a violation of the journal's standard protocols and is considered an infraction against the rigorous standards of scientific publishing.

The Editor and Publisher of Cancer Biotherapy and Radiopharmaceuticals are committed to preserving the scientific literature and the community it serves and does not tolerate any violations of scientific misconduct. Therefore, the publisher officially retracts the article.

Introduction

Glioma is a common primary intracranial malignant tumor, and the disease usually progresses quickly and is prone to relapse.¹ The rapidity and invasive nature of the disease have been challenging researchers and hindering progress toward effective treatment.² Currently, the main treatment methods for glioma are surgery combined with chemoradiotherapy, while the prognosis of patients is still not ideal.^3,4 Therefore, it is urgent to understand the factors affecting the progress of glioma so as to develop specific and effective treatment methods of glioma.

The occurrence of glioma is a complex process, including the regulation of long noncoding RNAs (lncRNAs) and microRNAs (miRNAs).^5,6 LncRNAs are a noncoding protein with a length of more than 200 bp.⁷ Studies have shown that lncRNAs can regulate gene expression through transcriptional, post-transcriptional, and epigenetic levels.^8,9 As the study progressed, the researchers have discovered that lncRNAs have a variety of action modes and functions in cells, the most important being as the competitive endogenous RNAs (ceRNAs), which inhibit the expression of miRNA target genes by complementary binding with miRNAs.¹⁰ In glioma, various lncRNAs, including OPA-interacting protein 5 antisense transcript 1 (OIP5-AS1), HOX transcript antisense intergenic RNA (HOTAIR), and lymphocytic leukemia 1 (DLEU1), were involved in tumor proliferation, metastasis, and prognosis,^11
–13 so it was of great value in the diagnosis and treatment of glioma.

Small nucleolar RNA host gene 16 (SNHG16), a member of the SNHG family, was highly expressed in many cancers.^14
–16 Previous study had reported that downregulation of SNHG16 suppressed the viability and increased the apoptosis of glioma cells, so SNHG16 might exert oncogenic function in glioma.^17
–19 Therefore, exploring the mechanism of SNHG16 is helpful to provide more references for the therapy of glioma.

In this research, the authors found that SNHG16 was highly expressed in glioma tissues and cells. Further mechanism studies had confirmed that SNHG16 could regulate poly(C)-binding protein 2 (PCBP2) expression through sponging microRNA-490 (miR-490), thereby promoting the glioma cell progression. These studies might provide a new perspective on the treatment of glioma.

Materials and Methods

Tissues sample collection and cells culture

Glioma tissues and adjacent normal tissues were collected from 31 glioma patients in the Department of Neurosurgery, The Fifth Affiliated Hospital of Sun Yat-Sen University. All patients received no anticancer treatment and signed informed consent forms. The Ethics Committee of Department of Neurosurgery, The Fifth Affiliated Hospital of Sun Yat-Sen University, approved the study protocol.

Glioma cell line (T98G) was bought from American Type Culture Collection (ATCC, Manassas, VA), and glioma cell line (U251) and normal human astrocytes (NHA) were obtained from BeNa Culture Collection (Beijing, China). All cells were cultured in Dulbecco's modified Eagle's medium (DMEM; Solarbio, Beijing, China) containing 10% fetal bovine serum (FBS; Sijiqing, Hangzhou, China) at 37°C and in a 5% CO₂ incubator.

Cells transfection

Small interfering RNA against SNHG16 (si-SNHG16) or overexpression vector (SNHG16) and their negative control (si-NC or vector), si-PCBP2, and its negative control (si-NC), PCBP2 overexpression vector (PCBP2), were bought from Genechem (Shanghai, China). The miR-490 mimic (miR-490), inhibitor (anti-miR-490), and their relative negative controls (miR-NC and anti-NC) were purchased from Ribobio (Guangzhou, China). All plasmids and vectors were transfected into U251 and T98G cells using Lipofectamine 3000 (Invitrogen, Carlsbad, CA).

Quantitative real-time polymerase chain reaction

Total RNA was extracted using TRIzol^® reagent (Invitrogen). Total RNA was reverse transcribed into first-strand cDNA using the PrimeScript™ RT Reagent kit (Takara, Dalian, China). Quantitative real-time polymerase chain reaction (qRT-PCR) was subsequently performed using an ABI 7900 real-time PCR system (ABI, Philadelphia, CA) and SYBR Green (Takara). Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and U6 were used as internal controls. The forward and reverse sequences were as follows: SNHG16: F, 5′-CAGAATGCCATGGTTTCCCC-3′ and R, 5′-TGGCAAGAGACTTCCTGAGG-3′; PCBP2: F, 5′-ATACGAGAGAGTACAGGGGC-3′ and R, 5′-GACCACCTGCAAAGATGACC-3′; GAPDH: F, 5′-TCAGTGGTGGACCTGACCTG-3′ and R, 5′-TGCTGTAGCCAAATTCGTTG-3′; MiR-490: F, 5′-CATGCAGCATGGAGTCCTCCAGGTTG-3′ and R, 5′-CAACCTGGAGGACTCCATGCTGAGCT-3′; and U6: F, 5′-CTCGCTTCGGCAGCACATA-3′ and R, 5′-AACGATTCACGAATTTGCGT-3′.

Cell viability detection

3-(4, 5-dimethyl-2 thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay was used to analyze the proliferation capacity of U251 and T98G cells. After transfection for 24 h, the cells were added with MTT solution per well, and then DMSO was added to dissolve. The absorbance at 490 nm was detected using a microplate reader (Bio-Rad, Hercules, CA).

Transwell assay

Transwell assay was conducted using 24-well chambers with an 8-μm polycarbonate membrane filter (Corning, Inc., Corning, NY), which were precoated with Matrigel (BD Biosciences, San Jose, CA) to detect cell invasion. U251 and T98G cells were inoculated into the upper chamber containing serum-free DMEM, while the lower chamber has DMEM containing 10% FBS. After 48 h, cells of the lower chamber were fixed with 4% methanol and stained with 0.05% crystal violet before being counted under a microscope (Shoif, Shanghai, China).

Western blot analysis

Total protein was extracted from glioma tissues and cells using RIPA buffer (Beyotime, Shanghai, China). BCA kit (Beyotime) was used to quantify total proteins to isolate the same amount of protein in sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) gel. Then, proteins in the SDS-PAGE gel were transferred onto PVDF membranes (Millipore, Billerica, MA). After blocking with 5% nonfat milk for 2 h, the membranes were cultured with the primary antibodies against PCBP2 (1:2000; Abcam, Cambridge, MA), proliferating cell nuclear antigen (PCNA, 1:2000; Abcam), Ki67 (1:5000; Abcam), matrix metalloproteinase 2 (MMP2, 1:1500; Abcam), MMP9 (1:1000; Abcam), E-cadherin (1:50; Abcam), N-cadherin (1:1000; Abcam), Vimentin (1:500; Abcam), or GAPDH (1:1000; Abcam) at 4°C overnight. Finally, the membranes were interacted with the secondary antibodies labeled with horseradish peroxidase (1:2000; Abcam) and visualized using ECL reagent (Beyotime).

Dual-luciferase reporter assay

SNHG16 and PCBP2 fragments containing miR-490 binding sites and mutant binding sites were inserted into the pmirGLO vector (Youbio, Changsha, China), yielding WT-SNHG16, MUT-SNGH16, WT-PCBP2-3′UTR, and MUT-PCBP2-3′UTR reporter plasmids, respectively. The above reporter plasmids were co-transfected with miR-490 mimic or miR-NC into U251 and T98G cells. The Firefly and Renilla luciferase signals were detected using the Dual-Luciferase Reporter Assay kit (Genomeditech, Shanghai, China).

Statistical analysis

All data were presented as the mean ± standard deviations. Two or multiple comparisons were performed by Student's t-test and one-way ANOVA. GraphPad Prism 5 software (GraphPad Software, La Jolla, CA) was used to calculate the statistical analyses. p < 0.05 was considered to be significant.

Results

SNHG16 was upregulated in glioma tissues and cells

First, the expression of SNHG16 in glioma was detected. As shown in Figure 1A, the relative SNHG16 expression was strikingly improved in glioma tissues compared with adjacent normal tissues. Furthermore, a notable increase of SNHG16 expression was observed in two glioma cell lines (U251 and T98G) compared with NHA cells (Fig. 1B). Therefore, the authors speculated that SNHG16 might involve in the regulation of glioma.

FIG. 1.

Upregulation of SNHG16 in glioma tissues and cells. (A) qRT-PCR analysis was used to measure SNHG16 expression in 31 pairs of glioma tissues and adjacent normal tissues. (B) The expression of SNHG16 in glioma cells (U251 and T98G) and NHA cells was evaluated by qRT-PCR. *p < 0.05. NHA, normal human astrocytes; qRT-PCR, quantitative real-time polymerase chain reaction; SNHG16, small nucleolar RNA host gene 16.

Knockdown of SNHG16 inhibited glioma cell proliferation, migration, and invasion

To investigate the role of SNHG16 in glioma, MTT and transwell assays were used to examine the effect of SNHG16 on glioma cell proliferation, migration, and invasion. As shown in Figure 2A and B, silencing of SNHG16 remarkably reduced the relative SNHG16 expression in U251 and T98G cells, indicating that the transfection efficiency of si-SNHG16 was good. MTT assay revealed that the ability of proliferation was significantly decreased in U251 and T98G cells transfected with si-SNHG16 compared with si-NC-transfected cells (Fig. 2C, D). Besides, SNHG16 silencing markedly reduced the number of migrated and invaded glioma cells (Fig. 2E–H). Meanwhile, the decreased protein levels of PCNA, Ki67, MMP2, and MMP9 also confirmed the conclusion that silenced SNHG16 hindered the proliferation, migration, and invasion of U251 and T98G cells (Supplementary Fig. S1A). In addition, SNHG16 knockdown increased the protein level of E-cadherin and decreased the N-cadherin and Vimentin protein levels, indicating that silencing of SNHG16 blocked the epithelial–mesenchymal transition (EMT) progress in U251 and T98G cells (Fig. 2I, J), which further verified that silenced-SNHG16 obviously suppressed the invasion and migration of glioma cells.

FIG. 2.

Silenced SNHG16 inhibited glioma cell progression. U251 and T98G cells were transfected with si-SNHG16 or si-NC. (A, B) The expression of SNHG16 in U251 and T98G cells was determined by qRT-PCR. (C, D) The proliferation of U251 and T98G cells was detected by MTT assay. (E–H) Transwell assay was performed to assess the migration and invasion of U251 and T98G cells. (I, J) The protein levels of E-cadherin, N-cadherin, and Vimentin in U251 and T98G cells were measured by WB analysis. *p < 0.05. MTT, 3-(4, 5-dimethyl-2 thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide; qRT-PCR, quantitative real-time polymerase chain reaction; SNHG16, small nucleolar RNA host gene 16; WB, Western blot.

MiR-490 was a target of SNHG16

To further study the molecular mechanism of SNHG16 on glioma progression, the authors predicted the potential target miRNAs of SNHG16 through the StarBase tool. As shown in Figure 3A, the potential complementary binding site between SNHG16 and miR-490 was presented. Then, dual-luciferase reporter assay results showed that miR-490 mimic could significantly repress the luciferase activity of WT-SNHG16, while there was no effect on MUT-SNHG16 in U251 and T98G cells (Fig. 3B, C), indicating the interaction between SNHG16 and miR-490. To further verify the relationship between miR-490 and SNHG16, they tested the expression of miR-490 in glioma and found that the expression of miR-490 was lower in glioma tissues and cells (Fig. 3D, F), and negatively correlated with SNHG16 expression (Fig. 3E). Subsequently, the SNHG16 overexpression vector and si-SNHG16 were used to detect the effect of SNGH16 on miR-490. qRT-PCR results found that the overexpression effect of the SNHG16 overexpression vector was good, and follow-up experiments could be carried out (Fig. 3G, H). The detection of miR-490 expression showed that the silencing of SNHG16 could remarkably enhance the miR-490 level, while overexpression of SNHG16 had opposite effect (Fig. 3I, J). These studies indicated that SNHG16 could absorb miR-490 in glioma cells.

FIG. 3.

SNHG16 could sponge miR-490. (A) The predicted target regions of SNHG16 containing miR-490 binding sites and mutant binding sites were shown. (B, C) Dual-luciferase reporter assay was used to evaluate the interaction between SNHG16 and miR-490 in U251 and T98G cells. (D) The expression of miR-490 in 31 pairs of glioma tissues and adjacent normal tissues was measured by qRT-PCR. (E) The correlation analysis between SNHG16 and miR-490 expression was determined by Pearson analysis. (F) MiR-490 expression in glioma cells and NHA cells was evaluated by qRT-PCR. (G, H) The transfection efficiency of SNHG16 overexpression vector was detected by qRT-PCR. (I, J) The expression of miR-490 in U251 and T98G cell-transfected si-SNHG16 or SNHG16 overexpression vector was tested by qRT-PCR. *p < 0.05. miR-490, microRNA-490; NHA, normal human astrocytes; qRT-PCR, quantitative real-time polymerase chain reaction; SNHG16, small nucleolar RNA host gene 16.

Overexpressed SNHG16 could reverse the suppression effect of miR-490 overexpression on glioma cell progression

Due to the low expression of miR-490 in glioma and its negative correlation with SNHG16, the authors investigated the role of miR-490 in glioma. qRT-PCR results showed that the miR-490 level was significantly upregulated in U251 and T98G cells by miR-490 mimic, suggesting the transfection of miR-490 mimic was successful (Fig. 4A, B). As shown in Figure 4C–H, MTT and transwell assays revealed that miR-490 overexpression markedly suppressed the viability and the number of migrated and invaded glioma cells, while overexpressed SNHG16 could restore this effect. Similarly, SNHG16 also inverted the inhibitory effect of miR-490 mimic on the protein levels of PCNA, Ki67, MMP2, and MMP9 (Supplementary Fig. S1B, C). Besides, SNHG16 could invert the suppression of miR-490 overexpression on E-cadherin protein level and the promotion of it on N-cadherin and Vimentin protein levels to accelerate the occurrence of EMT process (Fig. 4I, J), and further improved the migration and invasion of glioma cells.

FIG. 4.

Effects of miR-490 and SNHG16 overexpression on glioma cell progression. U251 and T98G cells were co-transfected with miR-490 mimic and SNGH16 overexpression vector or their negative control (miR-NC and vector). (A, B) The transfection efficiency of miR-490 mimic in U251 and T98G cells was detected by qRT-PCR. (C, D) The proliferation of U251 and T98G cells was evaluated by MTT assay. (E–H) Transwell assay was performed to assess the glioma cell migration and invasion. (I, J) E-cadherin, N-cadherin, and Vimentin protein levels were measured by WB analysis. *p < 0.05. miR-490, microRNA-490; MTT, 3-(4, 5-dimethyl-2 thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide; qRT-PCR, quantitative real-time polymerase chain reaction; SNHG16, small nucleolar RNA host gene 16; WB, Western blot.

MiR-490 targeted PCBP2 in glioma cells

To further identify the potential molecular mechanism of miR-490 on glioma, TargetScan online was used to predict the targets of miR-490. The authors found that PCBP2 3′UTR had binding sites with miR-490 (Fig. 5A), so they constructed WT-PCBP2-3′UTR and MUT-PCBP2-3′UTR for dual-luciferase reporter assay. The results indicated that the luciferase activity of WT-PCBP2-3′UTR rather than MUT-PCBP2-3′UTR was reduced by miR-490 mimic groups, suggesting that miR-490 could directly bind to PCBP2 (Fig. 5B, C). Moreover, a significant reversed correlation between miR-490 expression and PCBP2 expression had been identified (Fig. 5D). Besides, qRT-PCR results showed that PCBP2 was highly expressed in glioma tissues and cells (Fig. 5E, G), and the protein level was consistent with qRT-PCR results (Fig. 5F, H). The opposite expression trend of PCBP2 and miR-490 in glioma further confirmed the targeting relationship between them. Besides, the authors also evaluated the effect of miR-490 expression on PCBP2 expression. qRT-PCR showed that anti-miR-490 was effective in inhibiting miR-490 (Fig. 5I, J). The mRNA and protein detection results of PCBP2 showed that the abnormal expression of miR-490 blocked the level of PCBP2, while the inhibition of miR-490 promoted PCBP2 expression in U251 and T98G cells (Fig. 5K–N), which further proved the real inhibitory relationship between them.

FIG. 5.

PCBP2 was a target of miR-490. (A) The sequences of PCBP2 3′UTR containing miR-490 binding sites and mutant binding sites were described. (B, C) Dual-luciferase reporter assay was conducted to assess the interaction between miR-490 and PCBP2-3′UTR. (D) The correlation analysis between miR-490 and PCBP2 expression was determined by Pearson analysis. (E, F) The expression of PCBP2 in 31 pairs of glioma tissues and adjacent normal tissues was measured by qRT-PCR and WB analysis. (G, H) PCBP2 expression in glioma cells and NHA cells was detected by qRT-PCR and WB analysis. (I, J) The transfection efficiency of anti-miR-490 was explored by qRT-PCR. (K–N) The expression of PCBP2 in U251 and T98G cell-transfected miR-490 mimic or inhibitor was tested by qRT-PCR and WB analysis. *p < 0.05. miR-490, microRNA-490; NHA, normal human astrocytes; PCBP2, poly(C)-binding proteins 2; qRT-PCR, quantitative real-time polymerase chain reaction; WB, Western blot.

MiR-490 inhibitor recovered the suppression effect of PCBP2 silencing on glioma cell progression

To determine the role of PCBP2 in glioma cell progression, the authors co-transfected with si-PCBP2 and anti-miR-490 into U251 and T98G cells. The effectiveness of si-PCBP2 was confirmed by the detection of mRNA and protein levels of PCBP2 (Fig. 6A, B). MTT and transwell assays showed that knockdown of PCBP2 inhibited proliferation, migration, and invasion of U251 and T98G cells, while inhibition of miR-490 reversed the inhibitory effect of si-PCBP2 on glioma progression (Fig. 6C–H). Also, miR-490 inhibitor could invert the inhibition function of PCBP2 knockdown on the protein levels of PCNA, Ki67, MMP2, and MMP9 (Supplementary Fig. S1D, E). The detection of EMT-related proteins by Western blot analysis indicated that silenced PCBP2 suppressed the EMT process, while miR-490 inhibitor resumed the EMT process in U251 and T98G cells (Fig. 6I, J).

FIG. 6.

Effects of silenced-PCBP2 and miR-490 inhibitor on glioma cell progression. U251 and T98G cells were co-transfected with si-PCBP2 and anti-miR-490 or their negative control (si-NC and anti-NC). (A, B) The mRNA and protein levels of PCBP2 in U251 and T98G cells were detected by qRT-PCR and WB analysis to evaluate the transfection efficiency of si-PCBP2. MTT (C, D) and transwell assay (E–H) were employed to evaluate the proliferation, migration, and invasion rates of U251 and T98G cells. (I, J) WB analysis was performed to detect the protein levels of E-cadherin, N-cadherin, and Vimentin. *p < 0.05. miR-490, microRNA-490; MTT, 3-(4, 5-dimethyl-2 thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide; PCBP2, poly(C)-binding proteins 2; qRT-PCR, quantitative real-time polymerase chain reaction; WB, Western blot.

Overexpressed PCBP2 reversed the inhibition effect of miR-490 overexpression on glioma cell progression

At the same time, the authors also constructed the PCBP2 overexpression vector and explored the influence of PCBP2 overexpression on glioma progression regulated by miR-490 mimic. The elevated expression of PCBP2 confirmed the successful transfection of the PCBP2 overexpression vector in U251 and T98G cells (Supplementary Fig. S2A, B). Subsequently, miR-490 mimic and PCBP2 overexpression vector were co-transfected into U251 and T98G cells. Through detecting the viabilities and the number of migrated and invaded U251 and T98G cells, the authors observed that upregulation of PCBP2 could invert the inhibiting influence of miR-490 overexpression on the proliferation, migration, and invasion of glioma cells (Supplementary Fig. S2C–H). In addition, the decreasing effect of miR-490 overexpression on the protein levels of PCNA, Ki67, MMP2, and MMP9 also could be recovered by PCBP2 overexpression (Supplementary Fig. S1F, G). Furthermore, overexpressed PCBP2 also could reverse the suppression effect of miR-490 overexpression on the EMT process of glioma cells, as demonstrated by detecting the protein levels of E-cadherin, N-cadherin, and Vimentin in U251 and T98G cells (Supplementary Fig. S2I, J). All data confirmed that miR-490 regulated glioma progression through PCBP2.

SNHG16 promoted PCBP2 expression through miR-490

To confirm the regulatory network of SNHG16, the authors transfected miR-490 mimic and SNHG16 overexpression vector into U251 and T98G cells to measure the PCBP2 level. qRT-PCR results revealed that abnormal expression of miR-490 impeded PCBP2 level in U251 and T98G cells, while overexpression of SNHG16 increased the expression of PCBP2 (Fig. 7A, B). Protein results were consistent with the mRNA results (Fig. 7C, D). These confirmed that SNHG16 regulated the expression of PCBP2 by sponging miR-490.

FIG. 7.

Effects of SNHG16 and miR-490 expression on PCBP2 expression. U251 and T98G cells were transfected with miR-490 mimic and SNGH16 overexpression vector or their negative control (miR-NC and vector). (A, B) The expression of PCBP2 in U251 and T98G cells was detected by qRT-PCR. (C, D) The protein level of PCBP2 in U251 and T98G cells was evaluated by WB analysis. *p < 0.05. miR-490, microRNA-490; PCBP2, poly(C)-binding proteins 2; qRT-PCR, quantitative real-time polymerase chain reaction; SNHG16, small nucleolar RNA host gene 16; WB, Western blot.

Discussion

At present, the incidence and recurrence rate of glioma are high, and the therapeutic effect is not ideal.²⁰ The identification of useful biomarkers is of great significance to improve the prognosis of glioma patients. SNHG16, as a new lncRNA, has been found to be closely related to many cancers. Existing evidence had suggested that SNHG16 was improved in glioma, and silencing of it could decrease glioma tumorigenicity.^19,21 These previous findings were consistent with the results of this study. The authors discovered that SNHG16 expression was increased in glioma tissues and cells. Also, SNHG16 deletion suppressed glioma cell proliferation and metastasis. These results suggested that SNHG16 was involved in glioma tumor regulation as a procancer factor.

As a lncRNA, SNHG16 mainly acts as ceRNA to sponge miRNA and plays a regulatory role. For example, SNHG16 directly bonded with miR-195 to elevate the progression of hepatocellular carcinoma cells.²² Xu et al. demonstrated that SNHG16 could regulate miR-140-5p expression to accelerate the proliferation and colony formation of retinoblastoma cells.²³ In this study, the authors confirmed that miR-490 could directly interact with SNHG16 through bioinformatics prediction and dual-luciferase reporter assay validation. MiR-490 has been proved to participate in the occurrence of many cancers. For instance, Jia et al. demonstrated that miR-490 suppressed the presence and development of breast cancer.²⁴ Chen et al. uncovered that miR-490-3p blocked the tumorigenesis of ovarian epithelial carcinoma.²⁵ Besides, Li et al. verified that miR-490 regulated the metastasis of lung cancer cells.²⁶ Considering miR-490 expression in glioma was decreased and negatively correlated with SNHG16, they speculated that SNHG16 might promote the development of glioma by downregulating miR-490. After functional verification, they verified that the aberrant expression of miR-490 blocked the proliferation, migration, and invasion of glioma cells, while the SNHG16 overexpression could restore the suppression effect of miR-490 on glioma cells. These results confirmed the anticancer function of miR-490 in glioma cells.

PCBP2, a member of the PCBP family, has been reported to be involved in various tumorigenesis.^27
–29 In this research, PCBP2 was found to contain miR-490 binding sites by prediction, and its expression was regulated by miR-490. Previous studies had shown that PCBP2 deletion hindered glioma growth through the induction of apoptosis in glioma.²⁷ The overexpression of PCBP2 recovered the tumor-suppressive effect of miR-214.³⁰ Similarly, the authors found that PCBP2 was increased in glioma tissues and cells. MiR-490 inhibitor reversed the inhibition of glioma cell progression after PCBP2 knockdown. In addition, PCBP2 overexpression also could reverse the suppression effect of miR-490 overexpression on glioma cell progression. Therefore, they demonstrated that PCBP2 was a target gene of the SNHG16/miR-490 axis.

In summary, this study indicated that high expression of SNHG16 was related to glioma progression. SNHG16 regulated the expression of PCBP2 to accelerate the development of glioma cells through sponging miR-490. The discovery of the SNHG16/miR-490/PCBP2 axis provided a basis for the development of glioma and a strategy for the treatment of glioma.

Authors' Contributions

F.K., Y.Y., J.D., Y.Z., Y.L., H.L., and Y.W. contributed to the design of the study, data collection, statistical analysis, and data interpretation. F.K. and Y.W. contributed to data collection, article preparation, and the literature search. All authors read and approved the final article.

Footnotes

Disclosure Statement

No competing financial interests exist.

Funding Information

Supplementary Material

Supplementary Figure S1

Supplementary Figure S2

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