lncRNA Growth Arrest-specific Transcript 5 Research Articles

Upregulation of Long Noncoding RNA_GAS5 Suppresses Cell Proliferation and Metastasis in Laryngeal Cancer via Regulating PI3K/AKT/mTOR Signaling Pathway.

Background:Laryngeal cancer is one of the most common malignant tumors among head and neck cancers. Accumulating studies have indicated that long noncoding RNAs (lncRNAs) play an important role in laryngeal cancer occurrence and progression, however, the functional roles and relative regulatory mechanisms of lncRNA growth arrest-specific transcript 5 (GAS5) in laryngeal cancer progression remain unclear.Methods:The expression of lncRNA GAS5 in both laryngeal cancer tissues and cell lines was evaluated using quantitative reverse transcription-polymerase chain reaction (RT-qPCR) assay. The relationships between lncRNA GAS5 expression and clinical parameters were also analyzed. To determine the biological function of lncRNA GAS5, a lncRNA GAS5-specific plasmid was first transfected into laryngeal cancer cells using lentiviral technology. Cell counting kit-8 assay, flow cytometry, and Transwell assays were used to detect in vitro cell proliferation, apoptosis, cycle distribution, and metastasis abilities, respectively. Furthermore, in vivo cell growth experiments were also performed using nude mice. Additionally, western blotting was performed to identify the underlying regulatory mechanism.Results:In the current study, lncRNA GAS5 was downregulated in laryngeal cancer tissues and its low expression was closely associated with poor tumor differentiation, advanced TNM stage, lymph node metastasis, and shorter overall survival time. In addition, lncRNA GAS5 upregulation significantly inhibited laryngeal cancer cell proliferation both in vitro and in vivo. Moreover, in response to lncRNA GAS5 overexpression, more laryngeal cancer cells were arrested at the G2/M stage, accompanied by increased cell apoptosis rates and suppressed migration and invasion capacities. Mechanistically, our data showed that the overexpression of lncRNA GAS5 significantly regulated the PI3K/AKT/mTOR signaling pathway.Conclusion:LncRNA GAS5 might act as a suppressor gene during laryngeal cancer development, as it suppressed cell proliferation and metastasis by regulating the PI3K/AKT/mTOR signaling pathway; thus, lncRNA GAS5 is a promising therapeutic biomarker for the treatment of laryngeal cancer.

Downregulation of lncRNA GAS5 Alleviates Hippocampal Neuronal Damage in Mice with Depression-Like Behaviors Via Modulation of MicroRNA-26a/EGR1 Axis

BackgroundAccumulating evidences have demonstrated the roles of several long non-coding RNAs (lncRNAs) in depression. We aim to examine the capabilities of lncRNA growth arrest-specific transcript 5 (GAS5) on mice with depression-like behaviors and the mechanism of action. MethodsFifty-six healthy mice were selected for model establishment. Morris water maze test and trapeze test were performed for evaluating learning and memory ability. The binding relationship between lncRNA GAS5 and microRNA-26a (miR-26a) and the target relationship between miR-26a and EGR1 were verified by dual-luciferase reporter gene assay. The apoptosis of neurons in the hippocampal CA1 region of mice was detected by TUNEL staining. The expression of inflammatory factors, lncRNA GAS5, miR-26a, early growth response gene 1 (EGR1), phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway- and apoptosis-related factors in hippocampal tissues was tested by RT-qPCR and western blot analysis. ResultsmiR-26a expression was down-regulated while EGR1 and lncRNA GAS5 expression were up-regulated in hippocampal tissues of mice with depression-like behaviors. LncRNA GAS5 specifically bound to miR-26a and miR-26a targeted EGR1. Silencing of lncRNA GAS5 curtailed the release of inflammatory factors and the apoptosis of hippocampal neuron of mice with depression-like behaviors. EGR1 suppressed PI3K/AKT pathway activation to promote the release of inflammatory factors and the apoptosis of hippocampal neurons in mice with depression-like behaviors. ConclusionOur study provides evidence that silencing of lncRNA GAS5 could activate PI3K/AKT pathway to protect hippocampal neurons against damage in mice with depression-like behaviors by regulating the miR-26a/EGR1 axis.

LncRNA GAS5 sponges miR-362-5p to promote sensitivity of thyroid cancer cells to 131 I by upregulating SMG1.

This study aims to investigate the role of lncRNA growth arrest-specific transcript 5 (GAS5)/miR-362-5p/suppressor of morphogenesis in the genitalia 1 (SMG1) axis in 131 I-resistance in thyroid cancer (TC). GAS5, miR-362-5p, and SMG1 expression in TC tissues was assessed and the 131 I-resistant TC cells were established, which were treated with altered GAS5, miR-362-5p, and SMG1. The proliferation and apoptosis of 131 I-resistant TC cells were detected, and the expression of Akt/mTOR signaling pathway-related proteins was assessed. Binding relations between GAS5 and miR-362-5p, and miR-362-5p and SMG1 were confirmed. The role of GAS5 in 131 I-resistant TC cell growth in vivo was observed. GAS5 was downregulated and miR-362-5p was upregulated in TC tissues and 131 I-resistant cells. The 131 I-resistant TC cells had enhanced proliferation and repressed apoptosis, and the Akt/mTOR signaling pathway was activated. Overexpressed GAS5 strengthened 131 I sensitivity and suppressed TC cell growth, while upregulated miR-362-5p had an opposite effect. MiR-362-5p upregulation reversed the effect of GAS5, and SMG1 overexpression eliminated the impact of miR-362-5p upregulation on 131 I-resistant TC cells. GAS5 competitively binds to miR-362-5p and SMG1 is targeted by miR-362-5p. GAS5 sponges miR-362-5p to promote sensitivity of TC cells to 131 I by upregulating SMG1 and inactivating Akt/mTOR signaling pathway.

LncRNA GAS5 activates the AMPK pathway in peripheral blood mononuclear cells derived from rheumatoid arthritis patients.

Rheumatoid arthritis (RA) is an inflammatory disease, which seriously affects human joints. This study aimed to detect the changes in the expression of long non-coding RNA growth arrest-specific transcript 5 (GAS5) in peripheral blood mononuclear cells (PBMCs) derived from patients with RA and healthy controls (HC), as well as analyze the correlation between GAS5 and clinical indicators of RA. Also, the role and mechanism of GAS5 in regulating the AMP-activated protein kinase (AMPK) pathway in RA was further assessed. The PBMCs were isolated from the RA patients. Next, GAS5 expression was detected in RA PBMCs by quantitative real-time polymerase chain reaction, and its diagnostic value on RA was determined by receiver operating characteristic curves (ROC). The levels of interleukin (IL)-6 and IL-17 were detected via enzyme-linked immunosorbent assay. The expressions of total and phosphorylated AMPK as well as p38MAPK were determined with Western blot. GAS5 was down-regulated in RA PBMCs, and consequently serves as a potential diagnostic marker for RA (sensitivity, 90%; specificity, 80%; area under the curve, 0.89). Further, GAS5 negatively regulated erythrocyte sedimentation rate, C-reactive protein, Disease Activity Score of 28 joints and antibodies against cyclic citrullinated peptide, as well as the IL-6 and IL-17 levels of RA PBMCs. Similarly, GAS5 was observed to activate the AMPK pathway. GAS5 activated the AMPK pathway, while it negatively regulated the expression of cytokines IL-6 and IL-17.

<p>lncRNA GAS5 Is Upregulated in Osteoporosis and Downregulates miR-21 to Promote Apoptosis of Osteoclasts</p>

BackgroundIt has been reported that lncRNA growth arrest-specific transcript 5 (GAS5) interacts with miR-21, which plays critical roles in osteoporosis. The involvement of GAS5 in osteoporosis was investigated in this study.MethodsExpression levels of GAS5 and miR-21 in plasma of both osteoporosis patients and healthy controls were determined by RT-qPCR. Diagnostic values of GAS5 and miR-21 for osteoporosis were analyzed by ROC curve analysis. Overexpression experiments were used to assess the interactions between GAS5 and miR-21. The roles of GAS5 and miR-21 in the apoptosis of osteoclasts were investigated by cell apoptosis assay.ResultsThe present study aimed to investigate the roles of GAS5 in osteoporosis. The results showed that GAS5 was upregulated, while miR-21 was downregulated in plasma of osteoporosis patients. Expression levels of GAS5 and miR-21 were inversely correlated across plasma samples from osteoporosis patients but not the plasma samples from the controls. Altered expression of GAS5 and miR-21 distinguished osteoporosis patients from the controls. In osteoclasts, overexpression of GAS5 led to downregulation of miR-21, while overexpression of miR-21 did not affect the expression of GAS5. Overexpression of GAS5 led to promoted apoptosis of osteoclasts, while overexpression of miR-21 led to suppressed apoptosis of osteoclasts. In addition, overexpression of miR-21 attenuated the enhancing effects of overexpressing GAS5 on cell apoptosis.ConclusionGAS5 is upregulated in osteoporosis and may downregulate miR-21 to promote the apoptosis of osteoclasts.

Expression of the Long Noncoding RNA GAS5 Correlates with Liver Fibrosis in Patients with Nonalcoholic Fatty Liver Disease

Background: Advanced liver fibrosis is the most important prognostic factor in nonalcoholic fatty liver disease (NAFLD). The long noncoding RNA (lncRNA), growth arrest-specific transcript 5 (GAS5), is associated with the inhibition of liver fibrogenesis, and its levels are decreased in cirrhotic liver. Methods: We analyzed 51 patients with NAFLD, the diagnosis of which was confirmed by liver biopsy. Expression of GAS5 in both the liver and plasma of the patients was analyzed using a quantitative real-time polymerase chain reaction according to the fibrosis stage. Results: Plasma GAS5 expression was significantly higher in patients with advanced fibrosis than in those without. As the fibrosis progressed, GAS5 expression in plasma increased, with the exception of that in cirrhotic livers. Plasma levels of GAS5 were lower in patients with cirrhosis than in those with advanced fibrosis. Conclusion: Elevated circulating levels of the lncRNA GAS5 are associated with the progression of liver fibrosis prior to the development of cirrhosis.

LncRNA GAS5 attenuates fibroblast activation through inhibiting Smad3 signaling.

Transforming growth factor-β (TGF-β)-induced fibroblast activation is a key pathological event during tissue fibrosis. Long noncoding RNA (lncRNA) is a class of versatile gene regulators participating in various cellular and molecular processes. However, the function of lncRNA in fibroblast activation is still poorly understood. In this study, we identified growth arrest-specific transcript 5 (GAS5) as a novel regulator for TGF-β-induced fibroblast activation. GAS5 expression was downregulated in cultured fibroblasts by TGF-β and in resident fibroblasts from bleomycin-treated skin tissues. Overexpression of GAS5 suppressed TGF-β-induced fibroblast to myofibroblast differentiation. Mechanistically, GAS5 directly bound mothers against decapentaplegic homolog 3 (Smad3) and promoted Smad3 binding to Protein phosphatase 1A (PPM1A), a Smad3 dephosphatase, and thus accelerated Smad3 dephosphorylation in TGF-β-treated fibroblasts. In addition, GAS5 inhibited fibroblast proliferation. Importantly, local delivery of GAS5 via adenoviral vector suppressed bleomycin-induced skin fibrosis in mice. Collectively, our data revealed that GAS5 suppresses fibroblast activation and fibrogenesis through inhibiting TGF-β/Smad3 signaling, which provides a rationale for an lncRNA-based therapy to treat fibrotic diseases.

Long non-coding RNA GAS5 accelerates oxidative stress in melanoma cells by rescuing EZH2-mediated CDKN1C downregulation

BackgroundThe significance of long non-coding RNAs (lncRNAs) in mediating oxidative stress of cancers has been implicated recently. This study proposed a potential therapeutic target lncRNA growth arrest-specific transcript 5 (GAS5) for melanoma, due to its crucial role in oxidative stress and apoptosis of melanoma cells by regulating the enhancer of zeste homolog 2 (EZH2)-mediated CDKN1C expression.MethodsThe lncRNA GAS5 expression pattern was examined in melanoma tissues and cells. The correlation of lncRNA GAS5, EZH2, and CDKN1C with survival rate of melanoma patients was analyzed. In melanoma cell lines, lncRNA GAS5 expression was overexpressed or knocked down to clarify its effects on cell viability, apoptosis, and oxidative stress. The interaction between lncRNA GAS5 and EZH2 was examined by RIP and RNA pull-down assays followed by verification of the target relationship between EZH2 and CDKN1C.ResultsHigh expression of EZH2 and poor expression of lncRNA GAS5 and CDKN1C was observed in melanoma tissues and found to be correlated with the reduction in survival expectancy of melanoma patients. Overexpression of lncRNA GAS5 or CDKN1C or EZH2 knockdown could inhibit cell viability but enhance melanoma cell apoptosis and oxidative stress. Importantly, lncRNA GAS5 attenuated EZH2 expression by recruiting E2F4 to the EZH2 promoter region and knockdown of EZH2 upregulated CDKN1C expression by inhibiting the H3K27me3.ConclusionThe evidence provided by our study highlighted the involvement of lncRNA GAS5 in the translational suppression of EZH2 as well as the upregulation of CDKN1C, resulting in the promotion of melanoma cell apoptosis and oxidative stress.

Long non‑coding RNA GAS5 increases the radiosensitivity of A549 cells through interaction with the miR‑21/PTEN/Akt axis.

Radioresistance hinders the therapeutic outcomes of radiotherapy in non-small cell lung cancer (NSCLC). Although long non-coding RNAs (lncRNAs) have been demonstrated to participate in the regulation of multiple cell behaviors, whether they can modulate the radiosensitivity of NSCLC and the underlying molecular mechanisms have not been well investigated. In the present study, it was revealed that NSCLC NCI-H460 cells were more sensitive to ionizing radiation (IR) than A549 cells. Using the RNA-Seq method, four highly differentially expressed lncRNAs were identified, including the growth arrest-specific transcript 5 (GAS5), syntaxin binding protein 5 antisense RNA 1 (STXBP5-AS1), metastasis associated lung adenocarcinoma transcript 1 (MALAT1) and X-inactive specific transcript (XIST), which were predicted to play roles in the acquisition of radiosensitivity. Using real-time quantitative PCR (qPCR), it was demonstrated that lncRNA GAS5 was significantly upregulated in NCI-H460 cells but not in A549 cells during IR. Mechanistically, it was demonstrated that overexpression of lncRNA GAS5 decreased the level of microRNA-21 (miR-21). Overexpression of lncRNA GAS5 or suppression of miR-21 markedly increased the IR-induced cell apoptosis of A549 cells. It was also demonstrated that overexpression of lncRNA GAS5 increased PTEN expression and suppressed Akt phosphorylation through the modulation of miR-21. Notably, it was revealed that IR enhanced the interaction between lncRNA GAS5 and the miR-21/PTEN/Akt axis. In summary, the present findings revealed that lncRNA GAS5 has a radiosensitization effect on NSCLC, indicating the potential application of lncRNA GAS5 in NSCLC radiotherapy.

Danggui buxue tang inhibited mesangial cell proliferation and extracellular matrix accumulation through GAS5/NF-κB pathway

Diabetic nephropathy (DN) is the common complications of diabetes mellitus, but the efficacy of available treatments for the prevention of DN is still unsatisfactory. In the present study, we aimed to explore the effect of Danggui buxue tang (DGT) on the proliferation of high glucose (HG)-induced mesangial cells and accumulation of extracellular matrix in mesangial cells. We found DGT up-regulated the expression of growth arrest specific transcript 5 (GAS5) and IκB kinase (IKK) dose-dependently in mouse mesangial cells (SV40 MES-13). We found DGT regulated the expression IKK and the activity of nuclear transcription factor-κB (NF-κB) via GAS5, and proved that long non-coding RNA (lncRNA) GAS5 was positively related with IKK. And we proved GAS5 regulated the expression of IKK and the activity of NF-κB. In addition, DGT inhibited the viability of MES-13 cells and extracellular matrix-related proteins (laminin (LN), fibronectin (FN) and collagen IV (Col IV)) via GAS5. Moreover, we proved GAS5 regulated the viability of SV40 MES-13 cells and extracellular matrix-related proteins through NF-κB pathway. DGT inhibited the proliferation of mesangial cells and accumulation of extracellular matrix via GAS5/NF-κB, therefore, DGT could be an effective treatment for the prevention of DN.

LncRNA GAS5 regulates myocardial infarction by targeting the miR‐525‐5p/CALM2 axis

Long noncoding RNAs (lncRNAs) play critical roles in the pathogenesis of cardiovascular diseases, especially in myocardial infarction (MI). However, the underlying molecular mechanism of how lncRNA involves and affect MI still remains unclear. This study aimed to investigate the expression of lncRNA growth arrest-specific transcript 5 (GAS5) and its effects on myocardial cells' proliferation, cell cycle, and apoptosis. The possible mechanisms involved in GAS5, calmodulin 2 (CALM2), and microRNA (miR)-525-5p were also explored. The messenger RNA (mRNA) level of CALM2, GAS5, and miR-525-5p in postmyocardial infarction (MI) and normal cells were examined by quantitative real-time polymerase chain reaction (RT-qPCR). Western blot analysis assay was conducted to detect the protein levels of CALM2. The changes of cell cycle/apoptosis and cell viability of post-MI myocardial cells (PMMC) were determined by flow cytometry analysis and MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) assay after knockdown of GAS5 or CALM2, respectively. Dual luciferase reporter assay and RNA-binding protein immunoprecipitation (RIP) assay were performed to verify the targeting relationship between miR-525-5p and GAS5, CALM2 in myocardial. Hypoxic preconditioning was performed in normal cells, which constructed a simulated MI environment, and the effect of GAS5 on cardiomyocyte apoptosis was detected. Our data showed that the expression of GAS5 and CALM2 in PMMC was significantly upregulated, while the expression of miR-525-5p was downregulated. Overexpression of GAS5 and CALM2 profoundly promoted the apoptosis of myocardial cell. However, the proliferation of myocardial cell was inhibited by the upregulation of GAS5 and CALM2. Moreover, GAS5 was proved to be the target of miR-525-5p and GAS5 downregulated the expression of miR-525-5p and CALM2. In addition, lncRNA GAS5 promotes MI, while CALM2 induced MI can be reversed by miR-525-5p. These data suggested that lncRNA GAS5 promoted the development and progression of MI via targeting of the miR-525-5p/CALM2 axis and it has the potential to be explored as a therapeutic target for the treatment of MI in the future.

LncRNA GAS5 overexpression downregulates IL-18 and induces the apoptosis of fibroblast-like synoviocytes.

Long non-coding RNA (lncRNA) growth arrest specific transcript 5 (GAS5) negatively regulates interleukin-18 (IL-18) in ovarian cancer, while IL-18 contributes to the development of rheumatoid arthritis (RA). Therefore, GAS5 may also participate in RA. GAS5 and IL-18 in plasma of RA patients (n = 60) and healthy controls (n = 60) were measured by RT-qPCR and ELISA, respectively. Linear regression was performed to analyze the correlations between plasma levels of IL-18 and GAS5 in both RA patients and healthy controls. In the present study, we found that plasma GAS5 was downregulated, while IL-18 was upregulated in RA patients than in healthy controls. A significant and inverse correlation between GAS5 and IL-18 was found in RA patients but not in healthy controls. IL-18 treatment did not significantly alter the expression of GAS5 in fibroblast-like synoviocytes, while GAS5 overexpression led to the inhibited expression of IL-18. GAS5 overexpression also resulted in the promoted apoptosis of fibroblast-like synoviocytes. Therefore, GAS5 overexpression may improve RA by downregulating IL-18 and inducing the apoptosis of fibroblast-like synoviocytes. Key points • The present study mainly showed that overexpression of GAS5 may assist the treatment of RA. • The mechanism of GAS5 for the treatment of RA involves the downregulating inflammatory IL-18 and mediating the apoptosis of fibroblast-like synoviocytes. • GAS5 and IL-8 were correlated in RA patients but not in healthy controls.

LncRNA GAS5 acts as a ceRNA for miR-21 in suppressing PDGF-bb-induced proliferation and migration in vascular smooth muscle cells.

Aberrant proliferation and migration of vascular smooth muscle cells (VSMCs) contribute significantly to the development of many human cardiovascular diseases, including hypertension. The present study aimed to evaluate the in vitro functional roles of long noncoding RNA growth arrest-specific transcript 5 (GAS5) in VSMCs and explored the underlying molecular mechanisms. We found that GAS5 was significantly downregulated in PDGF-bb-treated VSMCs, and overexpression of GAS5 remarkably attenuated PDGF-bb-induced VSMC proliferation and migration. In addition, miR-21 was observed to potentially bind to GAS5, and we also identified that PDCD4 might be a direct target of miR-21 in VSMCs. Cotransfection of miR-21 mimics remarkably reduced the PDCD4 protein expression in GAS5 overexpressing VSMCs. Further, rescue experiments showed that enforced expression of miR-21 attenuated the inhibitory effects of GAS5 on VSMC proliferation and migration. Collectively, our results demonstrated that GAS5 inhibits PDGF-bb-induced VSMC proliferation and migration, partly through acting as a competing endogenous RNA of miR-21, and provided new evidence that GAS5 may serve as a potential therapeutic target for hypertension.

Tumor-derived exosomal lncRNA GAS5 as a biomarker for early-stage non-small-cell lung cancer diagnosis.

Diagnosis and treatment at an early stage may improve survival of non-small-cell lung cancer (NSCLC). Previous studies have found that long noncoding RNA growth arrest-specific transcript 5 (GAS5) is essential to cancer progression. However, the expression and diagnostic value of GAS5 in exosomes (Exo-GAS5) remain unclear. One hundred and four participants were enrolled, including subjects with NSCLC (n = 64) and healthy subjects ( n = 40). The total Exosome Isolation Kit was applied to isolate exosomes from serum. Total RNA was extracted and the AS5 expression was analyzed using quantitative reverse transcription polymerase chain reaction. Receiver operating characteristic (ROC) curve analysis was applied to evaluate the diagnostic value of Exo-GAS5 in NSCLC. Our data indicated that the Exo-GAS5 was downregulated in patients with NSCLC compared with healthy controls ( p < 0.001). Furthermore, patients with NSCLC with larger tumor size ( p = 0.025) and advanced TNM (T: extent of the primary tumor; N: lymph node involvement; M: metastatic disease) classification ( p = 0.047) showed lower Exo-GAS5 expression. ROC curve analysis using Exo-GAS5 combined with carcinoembryonic antigen showed an area under curve (AUC) of 0.929. Exo-GAS5 could be used to distinguish patients with Stage I NSCLC with an AUC of 0.822. In conclusion, Exo-GAS5 may function as an ideal noninvasive serum-based marker for identifying patients with early NSCLC.

LncRNA GAS5 restrains CCl4-induced hepatic fibrosis by targeting miR-23a through the PTEN/PI3K/Akt signaling pathway.

Hepatic fibrosis is chronic liver damage with many causes that has a relatively high death rate. The current study showed that long noncoding RNA (lncRNA) growth arrest-specific transcript 5 (GAS5), microRNA-23a (miR-23a), and phosphatase and tensin homolog (PTEN) play important roles in the pathological process of hepatic fibrosis but have a relatively unclear regulatory mechanism. This study aimed to investigate the roles of lncRNA GAS5, miR-23a, and PTEN in the pathological process of hepatic fibrosis and hepatic stellate cell (HSC) activation. We used carbon tetrachloride (CCl4) intraperitoneal injections to establish a rat hepatic fibrosis model and exogenous transforming growth factor-β1 to establish an HSC activation model. Quantitative RT-PCR, Western blot, dual-luciferase reporter system, and RNA pull-down assays were used to investigate which microRNAs and lncRNAs participate in the process of hepatic fibrosis and HSC activation. miR-23a expression increased significantly in hepatic fibrosis tissues and activated HSCs. miR-23a interaction with and degradation of PTEN further influenced the downstream signaling pathway phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin/Snail (PI3K/Akt/mTOR/Snail), causing E-cadherin expression levels to decrease and α-smooth muscle actin and collagen I expression levels to increase. lncRNA GAS5 can be used as a sponge platform for miR-23a to decrease miR-23a expression levels competitively. We revealed the role of the lncRNA GAS5/miR-23a/PTEN/PI3K/Akt/mTOR/Snail signaling pathway in hepatic fibrosis, providing molecular targets for the treatment of hepatic fibrosis. NEW & NOTEWORTHY This is the first study revealing that microRNA-23a (miR-23a) promotes hepatic fibrosis through the phosphatase and tensin homolog/phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin/Snail signaling pathway, and long noncoding RNA (lncRNA) growth arrest-specific transcript 5 (GAS5) can act as a sponge platform for miR-23a. Therefore, lncRNA GAS5/miR-23a may bring molecular targets for hepatic fibrosis therapy.

Long noncoding RNA GAS5 promotes apoptosis in primary nucleus pulposus cells derived from the human intervertebral disc via Bcl‑2 downregulation and caspase‑3 upregulation

Nucleus pulposus cell (NPC) apoptosis serves an important role in intervertebral disc degeneration (IDD); however, the roles of long noncoding RNAs (lncRNAs) in this process remain unknown. The present study aimed to determine the effects of the lncRNA growth arrest-specific transcript 5 (GAS5) on the apoptosis of primary human NPCs derived from the intervertebral disc, and to investigate the underlying mechanisms. TargetScan was used to predict the lncRNAs targeted by microRNA-155 (miR-155). Then, NPCs were subjected to lentivirus-mediated transduction of miR-155 or GAS5. A human lncRNA and mRNA array was used to screen differentially expressed lncRNAs following miR-155 overexpression. GAS5 and miR-155 expression levels were determined by reverse transcription-quantitative polymerase chain reaction. After GAS5 overexpression, apoptosis was assessed by flow cytometry via Annexin V/propidium iodide staining. Western blotting was employed to determine the expression of apoptosis-associated proteins, including caspase-3 and B cell lymphoma 2 (Bcl-2). TargetScan indicated GAS5 had one binding site for miR-155. Following exogenous transfection of miR-155 mimics, GAS5 expression levels in NPCs were significantly decreased (P<0.05). Interestingly, miR-155 overexpression in NPCs resulted in 721 differentially expressed lncRNAs compared with the negative control group (P<0.05), including 492 and 229 upregulated and downregulated lncRNAs respectively. In addition, 18 transcripts of GAS5 exhibited a downregulated expression profile. GAS5 overexpression in NPCs resulted in enhanced caspase-3 decreased Bcl-2 expression levels; the apoptosis of NPCs was significantly increased (P<0.05). The results of the present study revealed that overexpression of lncRNA GAS5 may promotes NPC apoptosis via Bcl-2 downregulation and caspase-3 upregulation, which may be associated with miR-155. The results of the present study suggest that lncRNA GAS5-silenced NPCs, or lentivirus-mediated lncRNA GAS5 knockdown may be precise and effective therapeutic strategies in the treatment of IDD.

LncRNA GAS5 suppresses proliferation, migration, invasion, and epithelial-mesenchymal transition in oral squamous cell carcinoma by regulating the miR-21/PTEN axis

Growth-arrest-specific transcript 5 (GAS5) functions as a tumor suppressor in a variety of cancers. GAS5 has been reported to be down-regulated in oral squamous cell carcinoma (OSCC). The aim of this study was to investigate the mechanisms of how GAS5 acts as a tumor suppressor in OSCC. qRT-PCR, cell viability, wound-healing, and transwell assays showed that knockdown of GAS5 increased miR-21 expression and promoted proliferation, migration, invasion, and epithelial-mesenchymal transition of OSCC cells. In contrast, overexpression of GAS5 showed the opposite effects. Furthermore, miR-21 overexpression reversed the effect of GAS5. Western blot showed that knockdown of GAS5 suppressed PTEN, while phosphorylation of Akt was promoted. PCNA, cyclinD1, and Ki-67 were up-regulated, indicating enhanced proliferation. E-cadherin was down-regulated, while N-cadherin, vimentin, and snail1 were increased, indicating augmented epithelial-mesenchymal transition. Overexpression of GAS5 regulated these proteins inversely. Overexpression of miR-21 reversed the effect of GAS5 on these proteins. Taken together, GAS5 suppresses proliferation, migration, invasion, and epithelial-mesenchymal transition in OSCC through the miR-21/PTEN axis and might be a novel therapeutic target for OSCC.

Role of signaling pathway of long non-coding RNA growth arrest-specific transcript 5/microRNA-200c-3p/angiotensin converting enzyme 2 in the apoptosis of human lung epithelial cell A549 in acute respiratory distress syndrome

Objective: To investigate whether long non-coding RNA (lncRNA) growth arrest-specific transcript 5 (GAS5)/microRNA-200c-3p/angiotensin converting enzyme 2(ACE2) involved in the regulation of the apoptosis of human lung epithelial cell A549 in acute respiratory distress syndrome (ARDS). Methods: ARDS rat models were established and were divided into control, ARDS, ARDS+ pcDNA and ARDS+ pcDNA-GAS5 groups. Six hours after the establishment of ARDS rat model, arterial blood and lung tissues of the rats from the four groups were collected. The changes of partial pressure of oxygen (PO(2)) and partial pressure of CO(2) (PCO(2)) were analyzed and the expression of GAS5 in lung tissue was observed in these groups. Then, A549 cells were divided into control, lipopolysaccharide (LPS), LPS+ pcDNA, LPS+ pcDNA-GAS5, LPS+ pcDNA-GAS5+ pre-NC, LPS+ pcDNA-GAS5+ miR-200c-3p mimic groups. Quantitative real-time PCR (qRT-PCR) was conducted to measure lncRNA GAS5, ACE2 and miR-200c-3p levels. RNA immunoprecipitation and RNA pull-down assay were used to detect the combination between GAS5 and miR-200c-3p. Western blotting was used to detect the protein level of ACE2. Flow cytometry was used to observe the apoptosis of A549 cells in those groups. The data between groups were compared by t test. Results: In ARDS rat model, PO(2) value was significantly increased in ARDS+ pcDNA-GAS5 group than that in ARDS+ pcDNA group[(81.5±3.3) vs (57.5±5.1) mmHg, t=4.850, P<0.05], and PCO(2) value was significantly decreased in ARDS+ pcDNA-GAS5 group than that in ARDS+ pcDNA group[(50.6±1.9) vs (64.0±1.9) mmHg, t=5.940, P<0.05]. LncRNA GAS5 level in A549 cells of LPS group decreased significantly than that in control group (0.43±0.01 vs 1.01±0.01, t=0.242, P<0.05). Compared with LPS+ pcDNA group, ACE2 expression increased significantly in LPS+ pcDNA-GAS5 group (0.85±0.04 vs 0.34±0.02, t=1.800, P<0.05). Compared with LPS+ pcDNA-GAS5+ pre-NC group, ACE2 expression decreased significantly in LPS+ pcDNA-GAS5+ miR-200c-3p mimic group (0.62±0.01 vs 0.84±0.02, t=9.440, P<0.05). Compared with control group, the percentage of A549 cell apoptosis promoted significantly in LPS group (25.90±0.61 vs 7.90±0.22, t=0.257, P<0.05). Compared with LPS+ pcDNA group, the percentage of A549 cell apoptosis suppressed significantly in LPS+ pcDNA-GAS5 group (10.50±0.37 vs 26.37±0.45, t=1.760, P<0.05). Compared with LPS+ pcDNA-GAS5+ pre-NC group, the percentage of A549 apoptosis promoted significantly in LPS+ pcDNA-GAS5+ miR-200c-3p mimic group (19.07±0.56 vs 10.87±0.26, t=0.643, P<0.05). Conclusion: In ARDS, down-regulation of lncRNA GAS5 decreases ACE2 expression through increasing miR-200c-3p to promote the apoptosis of A549 cells, thus to promote the progression of ARDS.

LncRNA GAS5 inhibits colorectal cancer cell proliferation via the miR‑182‑5p/FOXO3a axis.

Long non‑coding RNAs(lncRNAs) are mainly involved in diverse biological processes in human malignancies. The expression profile and underlying mechanism of the lncRNA growth arrest specific transcript5(GAS5) in colorectal cancer(CRC) are poorly understood. Here, we investigated the role of GAS5 in human CRC tissues. lncRNA GAS5 was specifically downregulated in CRC tissues and cell lines. Reduced GAS5 levels were significantly associated with advanced clinical stage and lymph node metastasis in CRC. GAS5 overexpression suppressed CRC cell proliferation and promoted cellular apoptosis. A dual‑luciferase reporter assay showed that GAS5 could negatively regulate the expression of microRNA(miR)‑182‑5p. Upregulated miR‑182‑5p abrogated the effect of GAS5 overexpression on CRC cell proliferation and apoptosis. Furthermore, GAS5 positively regulated the expression of FOXO3a in CRC cells. Taken together, these findings suggest that overexpression of the lncRNA GAS5 inhibits cell proliferation and promotes apoptosis by inhibiting miR‑182‑5p expression, and thus could be a therapeutic target in CRC.

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.