Knockdown of LINC01614 inhibits lung adenocarcinoma cell progression by up‐regulating miR‐217 and down‐regulating FOXP1

We tried to identify the function of LINC01614 in lung adenocarcinoma (LUAD) and reveal its underlying mechanisms. qRT‐PCR was applied to assess the expression of LINC016014 in LUAD tissues, noncancerous tissues and cells. Through colony formation assay, MTT assay and apoptosis analysis, we examined the variation of cell proliferation and apoptosis ability after silencing LINC01614. Moreover, the targeting interactions among LINC01614, miR‐217 and FOXP1 were validated via luciferase reporter assay, and then, we regulated the expression of miR‐217 and FOXP1 to ascertain their importance in cell proliferation and apoptosis. LINC01614 and FOXP1 were found to be up‐regulated in LUAD tumours and cells, whereas miR‐217 was down‐regulated. The experiment showed that target‐specific selectivity exists between LINC01614‐miR‐217 and miR‐217‐FOXP1 3′UTR. Furthermore, we disclosed that inhibition of LINC01614 could activate miR‐217, which subsequently restrained FOXP1. It was proved that LINC01614 promoted FOXP1 by inhibiting miR‐217, which ultimately stimulated the development of LUAD.     

MicroRNA‐130b targets PTEN to induce resistance to cisplatin in lung cancer cells by activating Wnt/β‐catenin pathway

More and more studies indicate the relevance of miRNAs in inducing certain drug resistance. Our study aimed to investigate whether microRNA‐130b‐3p (miR‐130b) mediates the chemoresistance as well as proliferation of lung cancer (LC) cells. MTS assay and apoptosis analysis were conducted to determine cell proliferation and apoptosis, respectively. Binding sites were identified using a luciferase reporter system, whereas mRNA and protein expression of target genes was determined by RT‐PCR and immunoblot, respectively. Mouse xenograft model was used to evaluate the role of miR‐130b in cisplatin resistance in vivo. The rising level of miR‐130b in cisplatin resistance LC cell lines (A549/CR and H446/CR ) versus its parental cell lines, indicated its crucial relevance for LC biology. We identified PTEN as miR‐130b's major target and inversely correlated with miR‐130b expression in LC. Moreover, excessive miR‐130b expression promoted drug resistance and proliferation, decreased apoptosis of A549 cells. Suppression of miR‐130b enhanced drug cytotoxicity and reduced proliferation of A549/CR cells both internally and externally. Particularly, miR‐130b mediated Wnt/β‐catenin signalling pathway activities, chemoresistance and proliferation in LC cell, which was partially blocked following knockdown of PTEN. These findings suggest that miR‐130b targets PTEN to mediate chemoresistance, proliferation, and apoptosis via Wnt/β‐catenin pathway. The rising level of miR‐130b in cisplatin resistance LC cell lines (A549/CR and H446/CR) versus its parental cell lines, indicated its crucial relevance for LC biology. Moreover, excessive miR‐130b expression promoted drug resistance and proliferation, decreased apoptosis of A549 cells. These findings suggest that miR‐130b targets PTEN to mediate chemoresistance, proliferation, and apoptosis via Wnt/β‐catenin pathway.     

microRNA‐145‐3p inhibits non‐small cell lung cancer cell migration and invasion by targeting PDK1 via the mTOR signaling pathway

The mammalian target of rapamycin (mTOR) pathway is dysregulated in more than 50% of all human malignancies and is a major target in cancer treatment. In this study, we explored the underlying mechanism involving microRNA‐145‐3p (miR‐145‐3p) in the development and progression of non‐small cell lung cancer (NSCLC) by targeting PDK1 via the mTOR signaling pathway. NSCLC tissues and adjacent normal tissues were obtained from 83 NSCLC patients. miR‐145‐3p, PDK1, and mTOR levels were determined by quantitative real‐time polymerase chain reaction (qRT‐PCR) and immunohistochemistry. Human NSCLC cell lines A549 and H1299 were transfected with miR‐145‐3p and siPDK1 to confirm the effect of miR‐145‐3p and PDK1 on NSCLC cells in vitro. Cell growth was evaluated by a CCK8 assay. Cell motility and chemotaxis analysis were determined by the scratch test and chemotaxis assay, respectively. The protein levels of PDK1 and mTOR were measured using the western blotting. Results showed lower level of miR‐145‐3p and higher levels of PDK1 and mTOR in NSCLC tissues compared to the adjacent normal tissues. In vitro results showed that cell growth, cell motility, and chemotaxis were all inhibited in cells transfected with miR‐145‐3p and those transfected with siPDK. Additionally, dual luciferase reporter gene assay helped confirmed that PDK1 is a target of miR‐145. Finally, levels of PDK1, mTOR, and phosphorylated‐mTOR were lower in cells transfected with miR‐145‐3p as well as those with siPDK1. These findings indicate that miR‐145‐3p may inhibit cell growth, motility, and chemotaxis in NSCLC by targeting PDK1 through suppressing the mTOR pathway.     

MicroRNA‐198 inhibition of HGF/c‐MET signaling pathway overcomes resistance to radiotherapy and induces apoptosis in human non–small‐cell lung cancer

Non–small‐cell lung cancer (NSCLC) is the most common cause of death from cancer worldwide. MicroRNAs (miRNAs) are a group of important regulators in NSCLC, including miR‐198. However, the underlying molecular mechanisms of miR‐198 involvement in intrinsic resistance to radiotherapy in NSCLC remain to be elucidated. In this study, to investigate the clinical significance of miR‐198 in NSCLC in relation to the response to radiotherapy, we determined the expression patterns of miR‐198 between responders and nonresponders after 2 months of radiotherapy and found that decreased expressions of miR‐198 were associated with radiotherapy resistance. In addition, we altered the endogenous miR‐198 using mimics or inhibitors to examine the effects of miR‐198 on 4‐Gy–irradiated A549 and SPCA‐1 cells in vitro. Upregulating miR‐198 was shown to inhibit cell proliferation, migration, and invasion and induce apoptosis. MiR‐198 inhibition produced a reciprocal result. PHA665752, a selective small‐molecule c‐Met inhibitor, potently inhibited hepatocyte growth factor (HGF)‐stimulated and constitutive c‐Met phosphorylation and rescued 4‐Gy–irradiated A549 and SPCA‐1 cells from miR‐198 inhibition. Most importantly, we established tumor xenografts of 4‐Gy–irradiated A549 and SPCA‐1 cells in nude mice and found that miR‐198 could suppress tumor formation. Hence, our data delineates the molecular pathway by which miR‐198 inhibits NSCLC cellular proliferation and induces apoptosis following radiotherapy, providing a novel target aimed at improving the radiotherapeutic response in NSCLC.     

MiR‐34b‐3p represses cell proliferation,cell cycle progression and cell apoptosis in non‐small‐cell lung cancer (NSCLC) by targeting CDK4

Lung cancer is the most common incident cancer, with a high mortality worldwide, and non‐small‐cell lung cancer (NSCLC) accounts for approximately 85% of cases. Numerous studies have shown that the aberrant expression of microRNAs (miRNAs) is associated with the development and progression of cancers. However, the clinical significance and biological roles of most miRNAs in NSCLC remain elusive. In this study, we identified a novel miRNA, miR‐34b‐3p, that suppressed NSCLC cell growth and investigated the underlying mechanism. miR‐34b‐3p was down‐regulated in both NSCLC tumour tissues and lung cancer cell lines (H1299 and A549). The overexpression of miR‐34b‐3p suppressed lung cancer cell (H1299 and A549) growth, including proliferation inhibition, cell cycle arrest and increased apoptosis. Furthermore, luciferase reporter assays confirmed that miR‐34b‐3p could bind to the cyclin‐dependent kinase 4 (CDK4) mRNA 3′‐untranslated region (3′‐UTR) to suppress the expression of CDK4 in NSCLC cells. H1299 and A549 cell proliferation inhibition is mediated by cell cycle arrest and apoptosis with CDK4 interference. Moreover, CDK4 overexpression effectively reversed miR‐34‐3p‐repressed NSCLC cell growth. In conclusion, our findings reveal that miR‐34b‐3p might function as a tumour suppressor in NSCLC by targeting CDK4 and that miR‐34b‐3p may, therefore, serve as a biomarker for the diagnosis and treatment of NSCLC.     

MiR‐376a suppresses the proliferation and invasion of non‐small‐cell lung cancer by targeting c‐Myc

It has been reported that miR‐376a is involved in the formation and progression of several types of cancer. However, the expression and function of miR‐376a is still unknown in non‐small cell lung carcinomas (NSCLC). In this study, the expression of miR‐376a in NSCLC tissues and cell lines were examined by real‐time PCR, the effects of miR‐376a on cell proliferation, apoptosis and invasion were evaluated in vitro. Luciferase reporter assay was performed to identify the targets of miR‐376a. The results showed that miR‐376a was significantly downregulated in NSCLC tissues and cell lines. Restoration of miR‐376a in NSCLC cell line A549 significantly inhibited cell proliferation, increased cell apoptosis and suppressed cell invasion, compared with control‐transfected A549 cells. Luciferase reporter assay showed that c‐Myc, an oncogene that regulating cell survival, angiogenesis and metastasis, was a direct target of miR‐376a. Over‐expression of miR‐376a decreased the mRNA and protein levels of c‐Myc in A549 cells. In addition, upregulation of c‐Myc inhibited miR‐376a‐induced inhibition of cell proliferation and invasion in A549 cells. Therefore, our results indicate a tumor suppressor role of miR‐376a in NSCLC by targeting c‐Myc. miR‐376a may be a promising therapeutic target for NSCLC.     

miR‐938 promotes cell proliferation by regulating RBM5 in lung adenocarcinoma cells

A growing body of research suggests that microRNAs (miRNAs) may play a key part in the progression of various cancers, including lung adenocarcinoma (LUAD). However, the expression and mechanism of miR‐938 (microRNA‐938) in LUAD have not been defined. Compared with adjacent tissues, the level of miR‐938 was up‐regulated in LUAD tissues. miR‐938 expression was significantly associated with tumor size. In vitro assays indicated that miR‐938 expression was also increased in the LUAD cell lines. Overexpression of miR‐938 promoted LUAD cell proliferation, whereas down‐regulation of miR‐938 had the opposite effect. We identified RNA‐binding protein 5 (RBM5) as a potential target gene of miR‐938 in LUAD. Expression of RBM5 was down‐regulated in LUAD tumor tissues and negatively correlated with expression of miR‐938. Up‐regulation of RBM5 reversed cell proliferation by inhibition of miR‐938 expression in LUAD cells. These results showed that miR‐938 may act as an oncogenic miRNA by targeting RBM5 in LUAD, indicating that miR‐938 could be used as a potential therapeutic target for LUAD patients.     

Up‐regulation of miR‐10b‐3p promotes the progression of hepatocellular carcinoma cells via targeting CMTM5

In this study, we investigated how miR‐10b‐3p regulated the proliferation, migration, invasion in hepatocellular carcinoma (HCC) at both in vitro and in vivo levels. CMTM5 was among the differentially expressed genes (data from TCGA). The expression of miR‐10b‐3p and CMTM5 was detected by qRT‐PCR and Western blot (WB). TargetScan was used to acquire the binding sites. Dual‐luciferase reporter gene assay was used to verify the direct target relationship between miR‐10b‐3p and CMTM5. WB analysis proved that miR‐10b‐3p suppressed CMTM5 expression. Furthermore, proliferation, invasion and migration of HCC cells were measured by MTT assay, colony formation assay, transwell assay and wound‐healing assay, respectively. Kaplan‐Meier plotter valued the overall survival of CMTM5. Finally, xenograft assay was also conducted to verify the effects of miR‐10b‐3p/CMTM5 axis in vivo. Up‐regulation of miR‐10b‐3p and down‐regulation of CMTM5 were detected in HCC tissues and cell lines. CMTM5 was verified as a target gene of miR‐10b‐3p. The overexpression of CMTM5 contributed to the suppression of the proliferative, migratory and invasive abilities of HCC cells. Moreover, the up‐regulation of miR‐10b‐3p and down‐regulation of CMTM5 were observed to be associated with worse overall survival. Lastly, we have confirmed the carcinogenesis‐related roles of miR‐10b‐3p and CMTM5 in vivo. We concluded that the up‐regulation of miR‐10b‐3p promoted the progression of HCC cells via targeting CMTM5.     

Baicalein inhibits cell growth and increases cisplatin sensitivity of A549 and H460 cells via miR‐424‐3p and targeting PTEN/PI3K/Akt pathway

Lung cancer is the leading cause of death in individuals with malignant disease. Non‐small‐cell lung cancer (NSCLC) is the most common type of lung cancer, and chemotherapy drugs such as cisplatin are the most widely used treatment for this disease. Baicalein is a purified flavonoid compound that has been reported to inhibit cancer cell growth and metastasis and increase sensitization to chemotherapeutic drugs via different pathways. Therefore, we assessed the effects of baicalein on the proliferation, apoptosis and cisplatin sensitivity in the NSCLC A549 and H460 cell lines and determined the pathways through which baicalein exerts its effects. Baicalein was slightly toxic to normal human bronchial NHBE cells but inhibited growth, induced apoptosis and increased cisplatin sensitivity in A549 and H460 cells. Baicalein down‐regulated miR‐424‐3p, up‐regulated PTEN expression and down‐regulated expression of PI3K and p‐Akt in A549 and H460 cells. Dual‐luciferase reporter assay demonstrated that PTEN is a target gene of miR‐424‐3p, and overexpression of miR‐424‐3p or silencing of PTEN partially attenuated the effects of baicalein on A549 and H460 cells. Taken together, we concluded that baicalein inhibits cell growth and increases cisplatin sensitivity to A549 and H460 cells via down‐regulation of miR‐424‐3p and targeting the PTEN/PI3K/Akt pathway.     

Circular RNA ciRS‐7 promotes tube formation in microvascular endothelial cells through downregulation of miR‐26a‐5p

Atherosclerosis is one of the most common and crucial heart diseases involving the heart and brain. At present, atherosclerosis and its major complications comprise the leading causes of death worldwide. Our purpose was to identify the role of ciRS‐7 in atherosclerosis. Tubulogenesis of HMEC‐1 cell was evaluated utilizing tube formation assay. Cell Counting Kit‐8 assay and flow cytometry were utilized to test viability and apoptosis. Migration assay was utilized to determine the migration capacity of experimental cells. Western blot was applied to examine apoptosis and tube formation‐associated protein expression. In addition, the above experiments were repeated when silencing ciRS‐7, overexpressing ciRS‐7, and upregulating miR‐26a‐5p. HMEC‐1 cells formed tube‐like structures over time. Silencing ciRS‐7 suppressed viability, migration, and tube formation but promoted apoptosis. Oppositely, overexpressing ciRS‐7 reversed the effect in HMEC‐1 cells. miR‐26a‐5p expression was elevated by silencing ciRS‐7 and reduced by overexpressing ciRS‐7. Moreover, overexpressing ciRS‐7 facilitated viability, migration, and tube formation via upregulating miR‐26a‐5p. Conclusively, overexpressing ciRS‐7 mobilized phosphoinositide 3‐kinase/protein kinase B (PI3K/AKT) pathway and suppressed c‐Jun N‐terminal kinase (JNK)/p38 pathway. ciRS‐7 exerted influence on apoptosis, viability, migration, and tube formation through mediating PI3K/AKT and JNK/p38 pathways by miR‐26a‐5p downregulation in HMEC‐1 cells.     

MicroRNA‐144‐3p suppressed TGF‐β1‐induced lung cancer cell invasion and adhesion by regulating the Src–Akt–Erk pathway

Lung cancer remains a leading cause to cancer‐related death worldwide. The anti‐cancer ability of microRNA‐144‐3p has been reported in many cancer types. This study focused on the mechanisms underlying miR‐144‐3p in inhibiting lung cancer. The expression levels of miR‐144‐3p and steroid receptor coactivator (Src) in different lung cancer cell lines and those in bronchial epithelial cells (16HBE) were compared. miR‐144‐3p mimic and siSrc were transfected into A549 cells. Under the conditions of transforming growth factor‐β1 (TGF‐β1). Small interfering transfection or TGF‐β1 treatment, cell invasive and adhesive abilities were analyzed by Transwell and cell adhesion assays. miR‐144‐3p inhibitor and siSrc were co‐transfected into A549 cells and the changes in cell invasion and adhesion were detected. The activation of Src–protein kinase B–extracellular‐regulated protein kinases (Src–Akt–Erk) pathway was determined using Western blot. The downregulated miR‐144‐3p and upregulated Src were generally detected in lung cancer cell lines and were the most significant genes in A549 cells. Both miR‐144‐3p overexpression and Src inhibition could obviously inhibit the invasion and adhesion abilities of A549 cells in the presence or absence of the effects of TGF‐β1. The inhibition of Src could block the promotive effects of miR‐144‐3p inhibitor and TGF‐β1 on cell invasion and adhesion. Furthermore, we found that miR‐144‐3p could negatively regulate the phosphorylation levels of Akt and Erk. Our data indicated the essential role of Src in the mechanisms underlying TGF‐β1‐induced cell invasion and adhesion of lung cancer, and that miR‐144‐3p could effectively suppress TGF‐β1‐induced aggressive lung cancer cells by regulating Src expression.     

Long noncoding RNA HOXA‐AS2 mediates microRNA‐106b‐5p to repress sepsis‐engendered acute kidney injury

HOXA cluster antisense RNA 2 (HOXA‐AS2) is a long noncoding RNA associated with the development of numerous cancers. But, whether HOXA‐AS2 exhibits a certain function in sepsis‐engendered acute kidney injury (AKI) remains uninvestigated. We strived to unveil the role of HOXA‐AS2 in sepsis‐engendered AKI. The expression of HOXA‐AS2 in sepsis patients, animal models and lipopolysaccharide (LPS)‐impaired HK‐2 cells was primarily assessed via a real‐time quantitative polymerase chain reaction. The effects of HOXA‐AS2 on cell survival of HK‐2 cells under LPS irritation were evaluated after overexpression of HOXA‐AS2. The correlation between HOXA‐AS2 and microRNA (miR)‐106b‐5p was forecasted via bioinformatics software and verified by using a luciferase report system. Subsequently, the functions of miR‐106b‐5p in LPS‐damaged HK‐2 cells were reassessed. Western blot was used for the determination of Wnt/β‐catenin and nuclear factor‐κB (NF‐κB) pathways. HOXA‐AS2 expression was decreased in sepsis patients, animal operation group and LPS‐irritated HK‐2 cells. Overexpressed HOXA‐AS2 mollified LPS‐triggered impairment in HK‐2 cells. In addition, a negative mediatory relation between HOXA‐AS2 and miR‐106b‐5p was predicated. Synchronously, overexpressed miR‐106b‐5p counteracted the protection of HOXA‐AS2 in LPS‐damaged HK‐2 cells. Ultimately, Wnt/β‐catenin and NF‐κB pathways were hindered by HOXA‐AS2 via targeting miR‐106b‐5p. HOXA‐AS2 exhibited protection in sepsis‐engendered AKI via targeting miR‐106b‐5p and hindering the Wnt/β‐catenin and NF‐κB pathways.     

Long noncoding RNA MALAT1 enhances the docetaxel resistance of prostate cancer cells via miR‐145‐5p‐mediated regulation of AKAP12

Our present work was aimed to study on the regulatory role of MALAT1/miR‐145‐5p/AKAP12 axis on docetaxel (DTX) sensitivity of prostate cancer (PCa) cells. The microarray data (GSE33455) to identify differentially expressed lncRNAs and mRNAs in DTX‐resistant PCa cell lines (DU‐145‐DTX and PC‐3‐DTX) was retrieved from the Gene Expression Omnibus (GEO) database. QRT‐PCR analysis was performed to measure MALAT1 expression in DTX‐sensitive and DTX‐resistant tissues/cells. The human DTX‐resistant cell lines DU145‐PTX and PC3‐DTX were established as in vitro cell models, and the expression of MALAT1, miR‐145‐5p and AKAP12 was manipulated in DTX‐sensitive and DTX‐resistant cells. Cell viability was examined using MTT assay and colony formation methods. Cell apoptosis was assessed by TUNEL staining. Cell migration and invasion was determined by scratch test (wound healing) and Transwell assay, respectively. Dual‐luciferase assay was applied to analyse the target relationship between lncRNA MALAT1 and miR‐145‐5p, as well as between miR‐145‐5p and AKAP12. Tumour xenograft study was undertaken to confirm the correlation of MALAT1/miR‐145‐5p/AKAP12 axis and DTX sensitivity of PCa cells in vivo. In this study, we firstly notified that the MALAT1 expression levels were up‐regulated in clinical DTX‐resistant PCa samples. Overexpressed MALAT1 promoted cell proliferation, migration and invasion but decreased cell apoptosis rate of PCa cells in spite of DTX treatment. We identified miR‐145‐5p as a target of MALAT1. MiR‐145‐5p overexpression in PC3‐DTX led to inhibited cell proliferation, migration and invasion as well as reduced chemoresistance to DTX, which was attenuated by MALAT1. Moreover, we determined that AKAP12 was a target of miR‐145‐5p, which significantly induced chemoresistance of PCa cells to DTX. Besides, it was proved that MALAT1 promoted tumour cell proliferation and enhanced DTX‐chemoresistance in vivo. There was an lncRNA MALAT1/miR‐145‐5p/AKAP12 axis involved in DTX resistance of PCa cells and provided a new thought for PCa therapy.     

miR‐34b‐5p inhibition attenuates lung inflammation and apoptosis in an LPS‐induced acute lung injury mouse model by targeting progranulin

Inflammation and apoptosis play important roles in the initiation and progression of acute lung injury (ALI). Our previous study has shown that progranulin (PGRN) exerts lung protective effects during LPS‐induced ALI. Here, we have investigated the potential roles of PGRN‐targeting microRNAs (miRNAs) in regulating inflammation and apoptosis in ALI and have highlighted the important role of PGRN. LPS‐induced lung injury and the protective roles of PGRN in ALI were first confirmed. The function of miR‐34b‐5p in ALI was determined by transfection of a miR‐34b‐5p mimic or inhibitor in intro and in vivo. The PGRN level gradually increased and subsequently significantly decreased, reaching its lowest value by 24 hr; PGRN was still elevated compared to the control. The change was accompanied by a release of inflammatory mediators and accumulation of inflammatory cells in the lungs. Using bioinformatics analysis and RT‐PCR, we demonstrated that, among 12 putative miRNAs, the kinetics of the miR‐34b‐5p levels were closely associated with PGRN expression in the lung homogenates. The gain‐ and loss‐of‐function analysis, dual‐luciferase reporter assays, and rescue experiments confirmed that PGRN was the functional target of miR‐34b‐5p. Intravenous injection of miR‐34b‐5p antagomir in vivo significantly inhibited miR‐34b‐5p up‐regulation, reduced inflammatory cytokine release, decreased alveolar epithelial cell apoptosis, attenuated lung inflammation, and improved survival by targeting PGRN during ALI. miR‐34b‐5p knockdown attenuates lung inflammation and apoptosis in an LPS‐induced ALI mouse model by targeting PGRN. This study shows that miR‐34b‐5p and PGRN may be potential targets for ALI treatments.     

MicroRNA‐876‐5p inhibits cell proliferation,migration and invasion by targeting c‐Met in osteosarcoma

Recently, aberrant expression of miR‐876‐5p has been reported to participate in the progression of several human cancers. However, the expression and function of miR‐876‐5p in osteosarcoma (OS) are still unknown. Here, we found that the expression of miR‐876‐5p was significantly down‐regulated in OS tissues compared to para‐cancerous tissues. Clinical association analysis indicated that underexpression of miR‐876‐5p was positively correlated with advanced clinical stage and poor differentiation. More importantly, OS patients with low miR‐876‐5p level had a significant shorter overall survival compared to miR‐876‐5p high‐expressing patients. In addition, gain‐ and loss‐of‐function experiments demonstrated that miR‐876‐5p restoration suppressed whereas miR‐876‐5p knockdown promoted cell proliferation, migration and invasion in both U2OS and MG63 cells. In vivo studies revealed that miR‐876‐5p overexpression inhibited tumour growth of OS in mice. Mechanistically, miR‐876‐5p reduced c‐Met abundance in OS cells and inversely correlated c‐Met expression in OS tissues. Herein, c‐Met was recognized as a direct target of miR‐876‐5p using luciferase reporter assay. Notably, c‐Met restoration rescued miR‐876‐5p attenuated the proliferation, migration and invasion of OS cells. In conclusion, these findings indicate that miR‐876‐5p may be used as a potential therapeutic target and promising biomarker for the diagnosis and prognosis of OS.     

Endoplasmic reticulum stress‐induced exosomal miR‐27a‐3p promotes immune escape in breast cancer via regulating PD‐L1 expression in macrophages

Immune escape of breast cancer cells contributes to breast cancer pathogenesis. Tumour microenvironment stresses that disrupt protein homeostasis can produce endoplasmic reticulum (ER) stress. The miRNA‐mediated translational repression of mRNAs has been extensively studied in regulating immune escape and ER stress in human cancers. In this study, we identified a novel microRNA (miR)‐27a‐3p and investigated its mechanistic role in promoting immune evasion. The binding affinity between miR‐27a‐3p and MAGI2 was predicted using bioinformatic analysis and verified by dual‐luciferase reporter assay. Ectopic expression and inhibition of miR‐27a‐3p in breast cancer cells were achieved by transduction with mimics and inhibitors. Besides, artificial modulation of MAGI2 and PTEN was done to explore their function in ER stress and immune escape of cancer cells. Of note, exosomes were derived from cancer cells and co‐cultured with macrophages for mechanistic studies. The experimental data suggested that ER stress biomarkers including GRP78, PERK, ATF6, IRE1α and PD‐L1 were overexpressed in breast cancer tissues relative to paracancerous tissues. Endoplasmic reticulum stress promoted exosome secretion and elevated exosomal miR‐27a‐3p expression. Elevation of miR‐27a‐3p and PD‐L1 levels in macrophages was observed in response to exosomes‐overexpressing miR‐27a‐3p in vivo and in vitro. miR‐27a‐3p could target and negatively regulate MAGI2, while MAGI2 down‐regulated PD‐L1 by up‐regulating PTEN to inactivate PI3K/AKT signalling pathway. Less CD4⁺, CD8⁺ T cells and IL‐2, and T cells apoptosis were observed in response to co‐culture of macrophages and CD3⁺ T cells. Conjointly, exosomal miR‐27a‐3p promotes immune evasion by up‐regulating PD‐L1 via MAGI2/PTEN/PI3K axis in breast cancer.     

MiR‐129‐5p inhibits glioma cell progression in vitro and in vivo by targeting TGIF2

This study purposed to explore the correlation between miR‐129‐5p and TGIF2 and their impacts on glioma cell progression. Differentially expressed miRNA was screened through microarray analysis. MiR‐129‐5p expression levels in glioma tissues and cells were measured by qRT‐PCR. CCK‐8 assay, flow cytometer, transwell assay and wound‐healing assay were employed to detect cell proliferation, apoptosis and cycle, invasiveness and migration, respectively. Dual‐luciferase reporting assay was performed to confirm the targeted relationship between miR‐129‐5p and TGIF2. The effects of TGIF2 expression on cell biological functions were also investigated using the indicated methods. Tumour xenograft was applied to explore the impact of miR‐129‐5p on tumorigenesis in vivo. MiR‐129‐5p expression was down‐regulated in both glioma tissues and glioma cells, while TGIF2 expression was aberrantly higher than normal level. Dual‐luciferase reporter assay validated the targeting relation between miR‐129‐5p and TGIF2. Overexpression of miR‐129‐5p or down‐regulation of TGIF2 inhibited the proliferation, invasion and migration capacity of glioma cells U87 and U251, and meanwhile blocked the cell cycle as well as induced cell apoptosis. MiR‐129‐5p overexpression repressed the tumour development in vivo. MiR‐129‐5p and TGIF2 had opposite biological functions in glioma cells. MiR‐129‐5p could inhibit glioma cell progression by targeting TGIF2, shining light for the development of target treatment for glioma.     

Muscle atrophy‐related myotube‐derived exosomal microRNA in neuronal dysfunction: Targeting both coding and long noncoding RNAs

In mammals, microRNAs can be actively secreted from cells to blood. miR‐29b‐3p has been shown to play a pivotal role in muscle atrophy, but its role in intercellular communication is largely unknown. Here, we showed that miR‐29b‐3p was upregulated in normal and premature aging mouse muscle and plasma. miR‐29b‐3p was also upregulated in the blood of aging individuals, and circulating levels of miR‐29b‐3p were negatively correlated with relative appendicular skeletal muscle. Consistently, miR‐29b‐3p was observed in exosomes isolated from long‐term differentiated atrophic C2C12 cells. When C2C12‐derived miR‐29b‐3p‐containing exosomes were uptaken by neuronal SH‐SY5Y cells, increased miR‐29b‐3p levels in recipient cells were observed. Moreover, miR‐29b‐3p overexpression led to downregulation of neuronal‐related genes and inhibition of neuronal differentiation. Interestingly, we identified HIF1α‐AS2 as a novel c‐FOS targeting lncRNA that is induced by miR‐29b‐3p through down‐modulation of c‐FOS and is required for miR‐29b‐3p‐mediated neuronal differentiation inhibition. Our results suggest that atrophy‐associated circulating miR‐29b‐3p may mediate distal communication between muscle cells and neurons.