MiR-519d-3p Suppresses Invasion and Migration of Trophoblast Cells via Targeting MMP-2

Our study was approved by the Medical Ethics Committee of Tang Du Hospital, Fourth Military Medical University and complied strictly with national ethical guidelines. Preeclampsia (PE) is a specific clinical disorder characterized by gestational hypertension and proteinuria and is a leading cause of maternal and perinatal mortality worldwide. The miR-519d-3p is upregulated in the maternal plasma of patients with PE which indicates a possible association between this microRNA and the pathogenesis of PE. No studies to date have addressed the effect of miR-519d-3p on the invasion and migration of trophoblast cells. In our study, we found that miR-519d-3p expression was elevated in placental samples from patients with PE. In vitro, overexpression of miR-519d-3p significantly inhibited trophoblast cell migration and invasion, whereas transfection of a miR-519d-3p inhibitor enhanced trophoblast cell migration and invasion. Luciferase assays confirmed that matrix metalloproteinase-2 (MMP-2) is a direct target of miR-519d-3p. Quantitative real-time PCR and western blot assays showed that overexpression of miR-519d-3p downregulated MMP-2 mRNA and protein expression. Knockdown of MMP-2 using a siRNA attenuated the increased trophoblast migration and invasion promoted by the miR-519d-3p inhibitor. In placentas from patients with PE or normal pregnancies, a negative correlation between the expression of MMP-2 and miR-519d-3p was observed using the Pearson correlation and linear regression analysis. Our present findings suggest that upregulation of miR-519d-3p may contribute to the development of PE by inhibiting trophoblast cell migration and invasion via targeting MMP-2; miR-519d-3p may represent a potential predictive and therapeutic target for PE.     

Extracellular vesicle-derived microRNA-18b ameliorates preeclampsia by enhancing trophoblast proliferation and migration via Notch2/TIM3/mTORC1 axis

Preeclampsia (PE), a common disorder of pregnancy, is characterized by insufficient trophoblast migration and inadequate vascular remodelling, such that promotion of trophoblast proliferation might ameliorate PE. In the current study, we sought to study the underlying mechanism of extracellular vesicle (EV)-derived microRNA-18 (miR-18b) in PE. Human umbilical cord mesenchymal stem cells (HUCMSCs) isolated from placental tissues were verified through osteogenic, adipogenic and chondrogenic differentiation assays. Bioinformatics analyses and dual-luciferase reporter gene assay were adopted to confirm the targeting relationship between miR-18b and Notch2. The functional roles of EV-derived miR-18b and Notch2 in trophoblasts were determined using loss- and gain-of-function experiments, and trophoblast proliferation and migration were assayed using CCK-8 and Transwell tests. In vivo experiments were conducted to determine the effect of EV-derived miR-18b, Notch2 and TIM3/mTORC1 in a rat model of PE, with monitoring of blood pressure and urine proteinuria. TUNEL staining was conducted to observe the cell apoptosis of placental tissues of PE rats. We found down-regulated miR-18b expression, and elevated Notch2, TIM3 and mTORC1 levels in the placental tissues of PE patients compared with normal placenta. miR-18b was delivered to trophoblasts and targeted Notch2 and negatively its expression, whereas Notch2 positively mediated the expression of TIM3/mTORC1. EV-derived miR-18b or Notch2 down-regulation enhanced trophoblast proliferation and migration in vitro and decreased blood pressure and 24 hours urinary protein in PE rats by deactivating the TIM3/mTORC1 axis in vivo. In summary, EV-derived miR-18b promoted trophoblast proliferation and migration via down-regulation of Notch2-dependent TIM3/mTORC1.     

Featured Article: microRNA-125a in pulmonary hypertension: Regulator of a proliferative phenotype of endothelial cells

Vascular remodeling due to excessive proliferation of endothelial and smooth muscle cells is a hallmark feature of pulmonary hypertension. microRNAs (miRNAs) are a class of small, non-coding RNA fragments that have recently been associated with remodeling of pulmonary arteries, in particular by silencing the bone morphogenetic protein receptor type II (BMPR2). Here we identified a novel pathway involving the concerted action of miR-125a, BMPR2 and cyclin-dependent kinase inhibitors (CDKN) that controls a proliferative phenotype of endothelial cells. An in silico approach predicted miR-125a to target BMPR2. Functional inhibition of miR-125a resulted in increased proliferation of these cells, an effect that was found accompanied by upregulation of BMPR2 and reduced expression of the tumor suppressors CDKN1A (p21) and CDKN2A (p16). These data were confirmed in experimental pulmonary hypertension in vivo. Levels of miR-125a were elevated in lung tissue of hypoxic animals that develop pulmonary hypertension. In contrast, circulating levels of miR-125a were found to be lower in mice with pulmonary hypertension as compared to control mice. Similar findings were observed in a small cohort of patients with precapillary pulmonary hypertension. These translational data emphasize the pathogenetic role of miR-125a in pulmonary vascular remodeling.     

The lncRNA MEG3 downregulation leads to osteoarthritis progression via miR-16/SMAD7 axis

Background

Osteoarthritis (OA) is a chronic joint disease and there is no a definitive cure at present. Long non-coding RNAs (lncRNAs) have been confirmed to play important roles in the development of OA. However, the underlying mechanism of lncRNA maternally expressed gene 3 (MEG3) in OA has not been well elucidated.

Methods

The rat OA model and interleukin-1β (IL-1β)-induced rat chondrocytes were constructed. The expression pattern of lncRNA MEG3 and miR-16 was detected by RT-qPCR assay in cartilage tissues of rat OA model. The effect of MEG3 and miR-16 on IL-1β-induced chondrocytes was evaluated on the basis of cell viability and apoptosis. Then, the interaction among MEG3, miR-16 SMAD7 was explored by dual-luciferase reporter assay and RIP assay.

Results

It is found that lncRNA MEG3 was down-regulated and miR-16 was up-regulated in rat OA cartilage tissues. MEG3 knockdown promoted proliferation and inhibited apoptosis, while miR-16 knockdown suppressed proliferation and promoted apoptosis in IL-1β-induced rat chondrocytes. Moreover, MEG3 was involved in miR-16 pathway and MEG3 suppressed miR-16 expression. Additionally, SMAD7 was a target gene of miR-16 and miR-16 suppressed SMAD7 expression in IL-1β-induced chondrocytes. Moreover, the expression of SMAD7 induced by MEG3 or si-MEG3 was markedly reversed by the introduction of miR-16 or anti-miR-16. Furthermore, MEG3 exerted its anti-proliferation and pro-apoptosis by regulating miR-16 and SMAD7.

Conclusion

MEG3 was down-regulated and miR-16 was up-regulated in cartilage tissues of rat OA model. MEG3 knockdown might lead to the progression of OA through miR-16/SMAD7 axis.

     

Retracted: Long noncoding RNA MEG3 is a tumor suppressor in choriocarcinoma by upregulation of microRNA-211

Tumor suppressor long noncoding RNA maternally expressed gene 3 (lncRNA MEG3) exists in various cancers. Nonetheless, the functions of lncRNA MEG3 in choriocarcinoma (CC) are still not well studied. We explored the effects of lncRNA MEG3 on human CC JEG-3 and BeWo cells. lncRNA MEG3 was overexpressed, and the effects of lncRNA MEG3 on cell viability, proliferation, apoptosis, migration, and invasion were assessed by the cell counting kit-8 assay, western blot analysis, flow cytometry (plus western blot analysis), and transwell assay (plus western blot analysis), respectively. Then, the expression level of miR-211 was detected by real-time quantitative polymerase chain reaction. After that, the effects of dysregulated microRNA-211 (miR-211) with overexpressing lncRNA MEG3 on JEG-3 cells and BeWo cells were testified. Western blot analysis was used to study the involvements of the signaling pathways in the lncRNA MEG3-associated modulation. We found that lncRNA MEG3 upregulation reduced cell viability, inhibited proliferation, migration and invasion, and promoted apoptosis. Expression of miR-211 was upregulated after lncRNA MEG3 overexpression. Effects of lncRNA MEG3 overexpression were augmented by miR-211 overexpression, while they were declined by miR-211 silencing. Phosphorylated levels of PI3K, AKT, and AMP-activated protein kinase (AMPK) were decreased by lncRNA MEG3 overexpression via regulation of miR-211. To sum up, lncRNA MEG3 could repress proliferation, migration and invasion, and promote apoptosis of JEG-3 and BeWo cells through upregulating miR-211. The PI3K/AKT and AMPK pathways were inhibited by lncRNA MEG3 overexpression via regulation of miR-211.     

A potential regulatory network among WDR86-AS1, miR-10b-3p,and LITAF is possibly involved in preeclampsia pathogenesis

Preeclampsia (PE), a pregnancy-specific disorder, is a leading cause of perinatal maternal and fetal mortality and morbidity. Impaired migration and invasion of trophoblastic cells and an imbalanced systemic maternal inflammatory response have been proposed as possible causes of pathogenesis of PE. Comparative analysis of PE-affected placentas and healthy placentas has uncovered differentially expressed long noncoding RNAs, microRNAs, and mRNAs. This study was conducted to investigate the effect of a regulatory network among these RNAs on PE pathogenesis. Long noncoding RNA WDR86-AS1, microRNA miR-10b-3p, and mRNA of protein LITAF were identified by screening of genes in existing databases with aberrant expression in PE-affected placentas and potential mutual interactions as revealed by TargetScan, miRanda, and PicTar analyses. This study identified their expression in PE-affected and healthy placentas by RT-PCR. An in vitro experiment was performed on human trophoblast HTR-8/SVneo cells cultured under normoxic or hypoxic conditions. MiR-10b-3p targets were identified in luciferase reporter assays and RNA pull-down assays. The mouse model of PE was set up using a soluble form of FLT-1 for in vivo testing. Lower levels of miR-10b-3p but higher expression of WDR86-AS1 and LITAF were observed in PE-affected placentas and trophoblast cells under hypoxia. WDR86-AS1 and LITAF mRNA were confirmed as targets of miR-10b-3p. WDR86-AS1 downregulated miR-10b-3p but promoted LITAF expression. Microarray analyses revealed that LITAF controlled the inflammatory responses and migration and proliferation of HTR-8/SVneo cells under hypoxia. Indeed, knockdown of WDR86-AS1 and LITAF or overexpression of miR-10b-3p attenuated the hypoxia-induced inhibition of cellular viability, migration, and invasion. Moreover, miR-10b-3p overexpression attenuated the pathological symptoms caused by soluble FLT-1 in vivo. In summary, the WDR86-AS1/miR-10b-3p/LITAF network is probably involved in PE pathogenesis.     

Aberrant expression of imprinted lncRNA MEG8 causes trophoblast dysfunction and abortion

Long noncoding RNAs (lncRNAs) are a group of noncoding RNAs whose nucleotides are longer than 200 bp. Previous studies have shown that they play an important regulatory role in many developmental processes and biological pathways. However, the contributions of lncRNAs to placental development are largely unknown. Here, our study aimed to investigate the lncRNA expression signatures in placental development by performing a microarray lncRNA screen. Placental samples were obtained from pregnant C57BL/6 female mice at three key developmental time points (embryonic day E7.5, E13.5, and E19.5). Microarrays were used to analyze the differential expression of lncRNAs during placental development. In addition to the genomic imprinting region and the dynamic DNA methylation status during placental development, we screened imprinted lncRNAs whose expression was controlled by DNA methylation during placental development. We found that the imprinted lncRNA Rian may play an important role during placental development. Its homologous sequence lncRNA MEG8 (RIAN) was abnormally highly expressed in human spontaneous abortion villi. Upregulation of MEG8 expression in trophoblast cell lines decreased cell proliferation and invasion, whereas downregulation of MEG8 expression had the opposite effect. Furthermore, DNA methylation results showed that the methylation of the MEG8 promoter region was increased in spontaneous abortion villi. There was dynamic spatiotemporal expression of imprinted lncRNAs during placental development. The imprinted lncRNA MEG8 is involved in the regulation of early trophoblast cell function. Promoter methylation abnormalities can cause trophoblastic cell defects, which may be one of the factors that occurs in early unexplained spontaneous abortion.     

miR-125b-1-3p inhibits trophoblast cell invasion by targeting sphingosine-1-phosphate receptor 1 in preeclampsia

Preeclampsia (PE) is the leading cause of maternal and perinatal mortality and morbidity. Understanding the molecular mechanisms underlying placentation facilitates the development of better intervention of this disease. MicroRNAs are strongly implicated in the pathogenesis of this syndrome. In current study, we found that miR-125b-1-3p was elevated in placentas derived from preeclampsia patients. Transfection of miR-125b-1-3p mimics significantly inhibited the invasiveness of human trophoblast cells, whereas miR-125b-1-3p inhibitor enhanced trophoblast cell invasion. Luciferase assays identified that S1PR1 was a novel direct target of miR-125b-1-3p in the placenta. Overexpression of S1PR1 could reverse the inhibitory effect of miR-125b-1-3p on the invasion of trophoblast cells. These findings suggested that abnormal expression of miR-125b-1-3p might contribute to the pathogenesis of preeclampsia.     

Subchronic nandrolone administration reduces cardiac oxidative markers during restraint stress by modulating protein expression patterns

lncRNAs are an emerging class of regulators involved in multiple biological processes. MEG3, an lncRNA, acts as a tumor suppressor, has been reported to be linked with osteogenic differentiation of MSCs. However, limited knowledge is available concerning the roles of MEG3 in the multilineage differentiation of hASCs. The current study demonstrated that MEG3 was downregulated during adipogenesis and upregulated during osteogenesis of hASCs. Further functional analysis showed that knockdown of MEG3 promoted adipogenic differentiation, whereas inhibited osteogenic differentiation of hASCs. Mechanically, MEG3 may execute its role via regulating miR-140-5p. Moreover, miR-140-5p was upregulated during adipogenesis and downregulated during osteogenesis in hASCs, which was negatively correlated with MEG3. In conclusion, MEG3 participated in the balance of adipogenic and osteogenic differentiation of hASCs, and the mechanism may be through regulating miR-140-5p.     

Circular RNA circ_0032962 promotes trophoblast cell progression as ceRNA to target PBX3 via sponging miR-326 in preeclampsia

Preeclampsia (PE) is the leading cause of maternal deaths in primipara. It is mainly characterized by defect migration and invasion of trophoblast cells. Circular RNAs (circRNAs) have been widely reported to be associated with PE progression. This study is designed to explore the role and mechanism of circ_0032962 on trophoblast cell behavior. Circ_0032962, microRNA-326 (miR-326), and Pre-B-cell leukemia homeobox 3 (PBX3) levels were measured by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation ability, migration, and invasion were measured by Cell Counting Kit-8 (CCK-8), 5-ethynyl-2′-deoxyuridine (EdU), Colony formation, wound healing, and transwell assays. Protein levels of E-cadherin, Vimentin, N-cadherin, and PBX3 were examined by western blot assay. The binding relationship between miR-326 and circ_0032962 or PBX3 was predicted by circular RNA Interactome or Starbase and then verified by a dual-luciferase reporter assay. Circ_0032962 and PBX3 levels were declined in placenta tissues from preeclampsia patients, and miR-326 was elevated. Apart from that, circ_0032962 knockdown could suppress cell proliferation ability, migration, invasion, and epithelial-mesenchymal transition (EMT) in trophoblast cells. Mechanically, circ_0032962 could affect PBX3 expression through sponging miR-326. Circ_0032962 could contribute to trophoblast cell growth ability and metastasis partly by regulating the miR-326/PBX3 axis, providing a novel insight into the pathogenesis and treatment of PE.     

Upregulated long noncoding RNA Linc00261 in pre-eclampsia and its effect on trophoblast invasion and migration via regulating miR-558/TIMP4 signaling pathway

Pre-eclampsia (PE) is a leading cause of maternal and perinatal morbidity and mortality but the exact underlying mechanisms of PE pathogenesis remain elusive. Accumulated data suggested that the long noncoding RNAs (lncRNAs) play important roles in the pathogenesis of PE. The present study identified the changes of lncRNA Linc00261 in PE and its effects on trophoblasts invasion and migration. Our results showed that the expression of Linc00261 was upregulated in placental tissues of PE women compared with those of healthy pregnant women. Overexpression of Linc00261 suppressed cell invasion and migration, induced cell apoptosis, and caused cell-cycle arrest at G₀/G₁ phase of HTR-8/SVneo cells; while knockdown of Linc00261 had the opposite effects on the HTR-8/SVneo cells. Mechanistic studies showed Linc00261 functioned as a competing endogenous RNA for miR-558 in HTR-8/SVneo cells, and miR-558 was negatively regulated by Linc00261. The expression level of miR-558 in the PE group was significantly lower than the control group, and the expression level of Linc00261 was negatively correlated with the expression level of miR-558 in the placental tissues of women with PE. Furthermore, miR-558 was found to negatively regulate the expression of TIMP metallopeptidase inhibitor 4 (TIMP4) via targeting the 3′ untranslated region in the HTR-8/SVneo cells. Overexpression of miR-558 increased HTR-8/SVneo cell invasion and migration, which was attenuated by TIMP4 overexpression. More importantly, both overexpression of miR-558 and knockdown of TIMP4 partially reversed the suppressive effects of Linc00261 overexpression on cell invasion and migration of HTR-8/SVneo cells. Collectively, our results for the first time showed the upregulation of Linc00261 in the placental tissues of severe PE patients. The mechanistic results indicated that Linc00261 exerted the suppressive effects on the trophoblast invasion and migration via targeting miR-558/TIMP4 axis, which may involve in the pathogenesis of PE.     

Down-regulation of lncRNA MEG3 promotes hypoxia-induced human pulmonary artery smooth muscle cell proliferation and migration via repressing PTEN by sponging miR-21

Hypoxia-induced pulmonary hypertension is a life-threatening disease arising from a progressive increase in pulmonary vascular resistance, irreversible pulmonary vascular remodeling and resulting in right ventricular failure. Recent studies suggested that pulmonary artery smooth muscle cell proliferation and migration played an important role in the pathogenesis of hypoxia-induced pulmonary hypertension. However, the mechanisms of hypoxia-induced pulmonary hypertension are complicated and largely unclear. In this study, we discovered that lncRNA MEG3 was down-regulated in human pulmonary artery smooth muscle cell in hypoxia, and inhibition of MEG3 promoted the cell proliferation and cell migration in both normal and hypoxia condition. Further study demonstrated that MEG3 exerted its function via regulation of miR-21 expression in both normal and hypoxia condition. In addition, we displayed the modulation of PTEN by miR-21 and their role in hypoxia. Ultimately, our study illustrated that MEG3 exerts its role via miR-21/PTEN axis in human pulmonary artery smooth muscle cell under both normal and hypoxia conditions.     

IGF2BP2 enhances LincRNA01116 stability via m6A: A potential biomarker and therapeutic target for patients with pre-eclampsia

Pre-eclampsia (PE) is a serious complication in pregnant women characterized by failure of placental remodeling and is one of the primary causes of changes in the placental structure and function. The aberrant expression of long noncoding RNA is associated with the occurrence and progression of PE. This study found that linc01116 expression was significantly downregulated in PE patients and was related to poor uterine spiral artery remodeling. Knockdown of linc01116 remarkably decreased the angiogenesis of trophoblast cells in vitro and in vivo. Mechanistically, IGF2BP2 regulated linc01116 RNA stability via m⁶A methylation. Bioinformatics and other experiments further revealed that linc01116 upregulates AAMP expression by adsorbing miR-210-3p in trophoblast cells. In conclusion, this study revealed the critical role of linc01116 in regulating trophoblast angiogenesis. Furthermore, the study provides new clues for detecting placental pathology in PE.     

Preeclampsia Is Associated with Alterations in the p53-Pathway in Villous Trophoblast

Background

Preeclampsia (PE) is characterized by exaggerated apoptosis of the villous trophoblast of placental villi. Since p53 is a critical regulator of apoptosis we hypothesized that excessive apoptosis in PE is mediated by abnormal expression of proteins participating in the p53 pathway and that modulation of the p53 pathway alters trophoblast apoptosis in vitro.

Methods

Fresh placental villous tissue was collected from normal pregnancies and pregnancies complicated by PE; Western blotting and real-time PCR were performed on tissue lysate for protein and mRNA expression of p53 and downstream effector proteins, p21, Bax and caspases 3 and 8. To further assess the ability of p53 to modulate apoptosis within trophoblast, BeWo cells and placental villous tissue were exposed to the p53-activator, Nutlin-3, alone or in combination with the p53-inhibitor, Pifithrin-α (PFT- α). Equally, Mdm2 was knocked-down with siRNA.

Results

Protein expression of p53, p21 and Bax was significantly increased in pregnancies complicated by PE. Conversely, Mdm2 protein levels were significantly depleted in PE; immunohistochemistry showed these changes to be confined to trophoblast. Reduction in the negative feedback of p53 by Mdm2, using siRNA and Nutlin-3, caused an imbalance between p53 and Mdm2 that triggered apoptosis in term villous explants. In the case of Nutlin, this was attenuated by Pifithrin-α.

Conclusions

These data illustrate the potential for an imbalance in p53 and Mdm2 expression to promote excessive apoptosis in villous trophoblast. The upstream regulation of p53 and Mdm2, with regard to exaggerated apoptosis and autophagy in PE, merits further investigation.     

MiR-141–3p promotes hypoxia-induced autophagy in human placental trophoblast cells

Preeclampsia (PE) is a pregnancy-specific disorder and a significant contributor to maternal, fetal and neonatal morbidity and mortality worldwide. Its pathogenesis is generally accepted as insufficient trophoblast invasion of the maternal endometrium and inadequate remodeling of the maternal spiral arteries. These impairments lead to elevated levels of hypoxia and oxidative stress. Autophagy has become a highly researched field in obstetrics, and this process may be essential for preimplantation development beyond the four- and eight-cell stages, and for blastocyst survival, extra-villous trophoblast functions, invasion and vascular remodeling. Several studies have shown that autophagy activation, shown by an increase in autophagy vacuoles or microtubule-associated protein 1 A/1B-light chain 3 (LC3) dots, was more common in PE than in normal pregnancy. Thus, changes in autophagic status are seen in preeclamptic placentas. MicroRNA-141–3p (miR-141–3p), a multifunctional miRNA, is involved in a variety of physiological and pathological processes, including PE and autophagy. However, the influence of miR-141–3p on autophagy regulation in trophoblast cells has yet to be described. Therefore, the objective of our study was to investigate the role of miR-141–3p in autophagy induced by hypoxia in human placental trophoblast cells. Our results found that hypoxia induced autophagy in trophoblast cells and dramatically elevated the expression of miR-141–3p. Overexpression of miR-141–3p improved autophagic activity, whereas low expression of miR-141–3p inhibited autophagic activity. Therefore, our data demonstrated that miR-141–3p promoted hypoxia-induced autophagy in placental trophoblast cells, which may be related to the development of preeclampsia.     

Hypoxia-inducible microRNA-218 inhibits trophoblast invasion by targeting LASP1: Implications for preeclampsia development

Preeclampsia (PE) is a major contributor to maternal morbidity and mortality. However, the molecular mechanisms underlying PE progression are not well characterized. Here, we investigated the role of miR-218 in PE development. The expression of miR-218 and its host genes SLIT2 and SLIT3 was up-regulated in preeclamptic placentae compared to normal placentae. miR-218 expression was induced by hypoxia and decreased after knockdown of HIF-1α in an extravillous trophoblast cell line (HTR-8/SVneo). Chromatin immunoprecipitation assays showed direct binding of HIF-1α to the promoters of SLIT2 and SLIT3. Bioinformatics analysis identified LASP1 as a direct target of miR-218. Overexpression of miR-218 repressed the expression of LASP1 at both the mRNA and protein level. Meanwhile, miR-218 repressed the activity of a luciferase reporter containing the 3′-untranslated region of the LASP1 gene. Furthermore, expression of LASP1 rescued the inhibitory effect of miR-218 on HTR-8/SVneo cell invasion. Together, these results indicated that miR-218 contributes to PE by targeting LASP1 to inhibit trophoblast invasion.     

LncRNA MEG3 inhibits the progression of prostate cancer by modulating miR‐9‐5p/QKI‐5 axis

This study was designed to detecting the influences of lncRNA MEG3 in prostate cancer. Aberrant lncRNAs expression profiles of prostate cancer were screened by microarray analysis. The qRT‐PCR and Western blot were employed to investigating the expression levels of lncRNA MEG3, miR‐9‐5p and QKI‐5. The luciferase reporter assay was utilized to testifying the interactions relationship among these molecules. Applying CCK‐8 assay, wound healing assay, transwell assay and flow cytometry in turn, the cell proliferation, migration and invasion abilities as well as apoptosis were measured respectively. LncRNA MEG3 was a down‐regulated lncRNA in prostate cancer tissues and cells and could inhibit the expression of miR‐9‐5p, whereas miR‐9‐5p down‐regulated QKI‐5 expression. Overexpressed MEG3 and QKI‐5 could decrease the abilities of proliferation, migration and invasion in prostate cancer cells effectively and increased the apoptosis rate. On the contrary, miR‐9‐5p mimics presented an opposite tendency in prostate cancer cells. Furthermore, MEG3 inhibited tumour growth and up‐regulated expression of QKI‐5 in vivo. LncRNA MEG3 was a down‐regulated lncRNA in prostate cancer and impacted the abilities of cell proliferation, migration and invasion, and cell apoptosis rate, this regulation relied on regulating miR‐9‐5p and its targeting gene QKI‐5.