MicroRNA‐155‐3p promotes glioma progression and temozolomide resistance by targeting Six1

The prognosis of glioma is generally poor and is the cause of primary malignancy in the brain. The role of microRNAs has been implicated in tumour inhibition or activation. In several cancers, the Six1 signalling pathway has been found to be aberrant and also relates to the formation of tumours. We analysed the database for expression profiles and clinical specimens of various grades of glioma to assess microRNA‐155‐3p (miR‐155‐3p) expression. The role of miR‐155‐3p in glioblastoma, cell cycle, proliferation, apoptosis and resistance to temozolomide was assessed in vitro through flow cytometry and cell proliferation assays. Bioinformatics analyses, and assays using luciferase reporter, and immunoblotting revealed that miR‐155‐3p targets Six1 and that the relationship between glioma and healthy brain tissues was significantly inverse. In rescue experiments, overexpressed Six1 revoked the changes in cell cycle distribution, proliferation and resistance to temozolomide estimated by apoptosis induced by overexpressed miR‐155‐3p. MiR‐155‐3p inhibition reduced glioma cell growth and proliferation in the brain of a mouse model and increased the survival of mice with gliomas. Thus, miR‐155‐3p modulates Six1 expression and facilitates the progression of glioblastoma and resistance to temozolomide and may act as a novel diagnostic biomarker and a target for glioma treatment.     

TP73‐AS1 promotes breast cancer cell proliferation through miR‐200a‐mediated TFAM inhibition

P73 antisense RNA 1T (TP73‐AS1 or PDAM) is a long non‐coding RNA, which can regulate apoptosis through regulation of p53 signaling‐related anti‐apoptotic genes. An abnormal change of TP73‐AS1 expression was noticed in cancers. The effects of TP73‐AS1 in breast cancer (BC) growth and the underlying mechanism remain unclear so far. In the present study, the effect of TP73‐AS1 in BC cell lines and clinical tumor samples was detected so as to reveal its role and function. In the present study, TP73‐AS1 was specifically upregulated in BC tissues and BC cell lines and was correlated to a poorer prognosis in patients with BC. TP73‐AS1 knocking down suppressed human BC cell proliferation in vitro through regulation of TFAM. In our previous study, we demonstrated that miR‐200a inhibits BC cell proliferation through targeting TFAM; here we revealed that TP73‐AS1 could regulate miR‐200a through direct targeting. Moreover, TP73‐AS1 might compete with TFAM for miR‐200a binding thus to promote TFAM expression. Data from the present study revealed that TP73‐AS1 promoted BC cell proliferation through acting as a competing endogenous RNA (ceRNA) by sponging miR‐200a. In conclusion, we regarded TP73‐AS1 as an oncogenic lncRNA promoting BC cell proliferation and a potential target for human BC treatment.     

Down‐regulated lncRNA SLC25A5‐AS1 facilitates cell growth and inhibits apoptosis via miR‐19a‐3p/PTEN/PI3K/AKT signalling pathway in gastric cancer

Mounting evidence has illustrated the vital roles of long non‐coding RNAs (lncRNAs in gastric cancer (GC). Nevertheless, the majority of their roles and mechanisms in GC are still largely unknown. In this study, we investigate the roles of lncRNA SLC25A5‐AS1 on tumourigenesis and explore its potential mechanisms in GC. The results showed that the expressions of SLC25A5‐AS1 in GC were significantly lower than that of adjacent normal tissues, which were significantly associated with tumour size, TNM stage and lymph node metastasis. Moreover, SLC25A5‐AS1 could inhibit GC cell proliferation, induce G1/G1 cell cycle arrest and cell apoptosis in vitro, as well as GC growth in vivo. Dual‐luciferase reporter assay confirmed the direct interaction between SLC25A5‐AS1 and miR‐19a‐3p, rescue experiment showed that co‐transfection miR‐19a‐3p mimics and pcDNA‐SLC25A5‐AS1 could partially restore the ability of GC cell proliferation and the inhibition of cell apoptosis. The mechanism analyses further found that SLC25A5‐AS1 might act as a competing endogenous RNAs (ceRNA), which was involved in the derepression of PTEN expression, a target gene of miR‐19a‐3p, and regulate malignant phenotype via PI3K/AKT signalling pathway in GC. Taken together, this study indicated that SLC25A5‐AS1 was down‐regulated in GC and functioned as a suppressor in the progression of GC. Moreover, it could act as a ceRNA to regulate cellular behaviours via miR‐19a‐3p/PTEN/PI3K/AKT signalling pathway. Thus, SLC25A5‐AS1 might be served as a potential target for cancer therapeutics in GC.     

Long non‐coding RNA AFAP1‐AS1/miR‐320a/RBPJ axis regulates laryngeal carcinoma cell stemness and chemoresistance

AFAP1‐AS1 is a long non‐coding RNA that is associated with tumorigenesis and poor prognosis in a variety of cancers. We have been suggested that AFAP1‐AS1 increases tumorigenesis in laryngeal carcinoma specifically by enhancing stemness and chemoresistance. We assessed AFAP1‐AS1 expression in human laryngeal specimens, paired adjacent normal tissues and human HEp‐2 cells. Indeed, we found not only that AFAP1‐AS1 was up‐regulated in laryngeal carcinoma specimens and cells, but also that stemness‐associated genes were overexpressed. Silencing of AFAP1‐AS1 promoted HEp‐2 cell chemoresistance under cisplatin treatment. Expression of AFAP1‐AS1 was increased in drug‐resistant Hep‐2 cells. We then probed the mechanism of AFAP1‐AS1 activity and determined that miR‐320a was a potential molecular target of AFAP1‐AS1. Luciferase reporter and qRT‐PCR assays of AFAP1‐AS1 and miR‐320a levels in human specimens and cell cultures indicated that AFAP1‐AS1 negatively regulates miR‐320a. To discover the molecular mechanism of miR‐320a, we again used the DIANA Tools algorithm to predict its genetic target, RBPJ. After cloning the 3′‐untranslated regions (3′‐UTR) of RBPJ into a luciferase reporter, we determined that miR‐320a did in fact reduce RBPJ mRNA and protein levels. Ultimately, we determined that AFAP1‐AS1 increases RBPJ expression by negatively regulating miR‐320a and RBPJ overexpression rescues stemness and chemoresistance inhibited by AFAP1‐AS1 silencing. Taken together, these results suggest that AFAP1‐AS1 can serve as a prognostic biomarker in laryngeal carcinoma and that miR‐320a has the potential to improve standard therapeutic approaches to the disease, especially for cases in which cancer cell stemness and drug resistance present significant barriers to effective treatment.     

Down‐regulated lncRNA SBF2‐AS1 in M2 macrophage‐derived exosomes elevates miR‐122‐5p to restrict XIAP,thereby limiting pancreatic cancer development

Evidence has indicated that M2 macrophages promote the progression of cancers, but few focus on the ability of M2 macrophage‐derived exosomes in pancreatic cancer (PC). This study aims to explore how M2 macrophages affect malignant phenotypes of PC through regulating long non‐coding RNA SET‐binding factor 2 antisense RNA 1 (lncRNA SBF2‐AS1)/microRNA‐122‐5p (miR‐122‐5p)/X‐linked inhibitor of apoptosis protein (XIAP) axis. THP‐1 cells were transformed into M1 macrophages by lipopolysaccharide and interferon‐γ treatment, and into M2 macrophages after interleukin‐4 treatment. The PANC‐1 PC cell line with the largest lncRNA SBF2‐AS1 expression was selected, and M2 macrophage‐derived exosomes were isolated and identified. A number of assays were applied for the examination of lncRNA SBF2‐AS1 expression, PC cell biological functions and subcellular localization of lncRNA SBF2‐AS1. XIAP expression was detected, along with the interaction among lncRNA SBF2‐AS1, miR‐122‐5p and XIAP. M2 macrophage exosomal lncRNA SBF2‐AS1 expression's effects on the tumorigenic ability of PANC‐1 cells in nude mice were also investigated. M2 macrophage‐derived exosomes promoted progression of PC cells. Overexpressed lncRNA SBF2‐AS1 promoted progression of PC cells. LncRNA SBF2‐AS1 was found to act as a competing endogenous RNA to repress miR‐122‐5p and up‐regulate XIAP. Constrained lncRNA SBF2‐AS1 in M2 macrophage‐derived exosomes contributed to restraining tumorigenic ability of PC cells. Collectively, our study reveals that constrained lncRNA SBF2‐AS1 in M2 macrophage‐derived exosomes increases miR‐122‐5p expression to restrain XIAP expression, which further inhibits PC progression.     

LncRNA NR2F1‐AS1 regulates hepatocellular carcinoma oxaliplatin resistance by targeting ABCC1 via miR‐363

Emerging evidence has validated the vital role of long non‐coding RNA (lncRNA) in the chemoresistance of cancer treatment. In the present study, we investigate the function of lncRNA NR2F1‐AS1 on oxaliplatin (OXA) resistance of hepatocellular carcinoma (HCC) and discover the underlying molecular mechanism. Results revealed that lncRNA NR2F1‐AS1 was up‐regulated in oxaliplatin‐resistant HCC tissue and cells using microarray analysis and RT‐PCR. Meanwhile, ABCC1 protein was overexpressed in OXA‐resistant HCC cells (Huh7/OXA and HepG2/OXA). In vitro, NR2F1‐AS1 knockdown reduced the invasion, migration, drug‐resistant gene (MDR1, MRP5, LRP1) and IC50 value in Huh7/OXA and HepG2/OXA cells. In vivo, NR2F1‐AS1 knockdown decreased the tumour weight of HCC cells. Bioinformatics tools and luciferase reporter assay confirmed miR‐363 targeted the 3′‐UTR of NR2F1‐AS1 and ABCC1 mRNA, presenting that NR2F1‐AS1 promoted ABCC1 expression through endogenous sponging miR‐363. In summary, results conclude that NR2F1‐AS1 regulates HCC OXA resistance through targeting miR‐363‐ABCC1 pathway, providing a vital theoretic mechanism and therapeutic target for HCC chemoresistance.     

The HNF1A-AS1/miR-92a-3p axis affects the radiosensitivity of non-small cell lung cancer by competitively regulating the JNK pathway

Background

It has been widely reported that long non-coding RNAs (lncRNAs) could affect the varieties of tumor response to radiotherapy. LncRNA HNF1A-AS1 is transcribed from HNF1A gene cluster’s antisense strand. This work focused on the mechanism of how HNF1A-AS1 participated in the radiosensitivity of non-small cell lung cancer (NSCLC).

Methods

The mRNA or protein expression of HNF1A-AS1, miR-92a-3p MAP2K4, and JNK in NSCLC cells and tissues was detected by qRT-PCR or western blotting. RNA immunoprecipitation (RIP) detection and luciferase reporting system were used to evaluate the relationship between HNFA-AS1 and miR-92a-3p or between miR-92a-3p and MAP2K4. Flow cytometry assays, colony formation, and MTT were performed to analyze the function changes in A549 and Calu-1 cells. The rescue experiment was also conducted to explore the underlying mechanisms.

Results

HNF1A-AS1 was investigated in NSCLC cells and tissues and highly related to the advanced pathological stage. HNF1A-AS1 bound with miR-92a-3p, which was downregulated in NSCLC. It showed that miR-92a-3p was negatively related to HNF1A-AS1. Knockdown of HNF1A-AS1 impacted most cell biological behaviors in NSCLC cells, including restricting the proliferation and aggravating apoptosis. Furthermore, knockdown of HNF1A-AS1 dramatically enhanced radiotherapy sensitivity of NSCLC. Moreover, miR-92a-3p was found to target MAP2K4 and could reduce MAP2K4 expression. Inhibition of HNF1A-AS1 elevated radiotherapy sensitivity and retarded the progression of NSCLC cells, followed by decreasing expression levels of MAP2K4. Besides, MAP2K4 mimic rescued the si-HNF1A-AS1 effects on the biological behavior of NSCLC cells.

Conclusion

HNF1A-AS1 is highly expressed in NSCLC. MiR-92a-3p is the target gene of HNF1A-AS1 and involved in tumor progression by regulating the MAP2K4/JNK pathway. HNF1AS1/miR-92a-3p/MAP2K4 axis plays important roles in radiotherapy resistance of NSCLC.

Graphical abstract

     

MircoRNA‐1275 promotes proliferation,invasion and migration of glioma cells via SERPINE1

This study was designed to explore the relationship between miR‐1275 and SERPINE1 and its effects on glioma cell proliferation, migration, invasion and apoptosis. Differentially expressed miRNAs and mRNAs in glioma tissues were screened out by bioinformatic analysis. Dual‐luciferase reporter gene assay was used to validate the targeted relationship between miR‐1275 and SERPINE1. qRT‐PCR was used to detect the expression of miR‐1275 and SERPINE1 in glioma tissues. The expressions of SERPINE1 and p53 pathway‐related proteins in glioma cells were detected by western blot. Glioma cell proliferation, apoptosis, migration and invasion were respectively detected by CCK‐8 assay, flow cytometry, wound healing assay and transwell assay. Tumour xenograft model was developed to study the influence of miR‐1275 and SERPINE1 on glioma growth in vivo. The results of microarray analysis, qRT‐PCR and western blot showed that miR‐1275 was low‐expressed while SERPINE1 was high‐expressed in glioma. Dual‐luciferase assay showed that miR‐1275 could bind to SERPINE1. Overexpression of miR‐1275 could promote the p53 pathway‐related proteins’ expression. Highly expressed miR‐1275 could repress the migration, proliferation and invasion of glioma cells while highly expressed SERPINE1 had inverse effects. Tumour xenograft showed that up‐regulated miR‐1275 or down‐regulated SERPINE1 could repress glioma growth in vivo. Up‐regulation of miR‐1275 activated p53 signalling pathway via regulating SERPINE1 and therefore suppressed glioma cell proliferation, invasion and migration, whereas promoted cell apoptosis.     

LncRNA HOXA11‐AS regulates calcium oxalate crystal–induced renal inflammation via miR‐124‐3p/MCP‐1

Long noncoding RNA (lncRNA) has been suggested to play an important role in a variety of diseases over the past decade. In a previous study, we identified a novel lncRNA, termed HOXA11‐AS, which was significantly up‐regulated in calcium oxalate (CaOx) nephrolithiasis. However, the biological function of HOXA11‐AS in CaOx nephrolithiasis remains poorly defined. Here, we demonstrated that HOXA11‐AS was significantly up‐regulated in CaOx nephrolithiasis both in vivo and in vitro. Gain‐/loss‐of‐function studies revealed that HOXA11‐AS inhibited proliferation, promoted apoptosis and aggravated cellular damage in HK‐2 cells exposed to calcium oxalate monohydrate (COM). Further investigations showed that HOXA11‐AS regulated monocyte chemotactic protein 1 (MCP‐1) expression in HK‐2 cell model of CaOx nephrolithiasis. In addition, online bioinformatics analysis and dual‐luciferase reporter assay results showed that miR‐124‐3p directly bound to HOXA11‐AS and the 3'UTR of MCP‐1. Furthermore, rescue experiment results revealed that HOXA11‐AS functioned as a competing endogenous RNA to regulate MCP‐1 expression through sponging miR‐124‐3p and that overexpression of miR‐124‐3p restored the inhibitory effect of proliferation, promotion effects of apoptosis and cell damage induced by HOXA11‐AS overexpression. Taken together, HOXA11‐AS mediated CaOx crystal–induced renal inflammation via the miR‐124‐3p/MCP‐1 axis, and this outcome may provide a good potential therapeutic target for nephrolithiasis.     

Long non‐coding RNA F11‐AS1 inhibits HBV‐related hepatocellular carcinoma progression by regulating NR1I3 via binding to microRNA‐211‐5p

Long non‐coding RNAs (lncRNAs) could regulate growth and metastasis of hepatocellular carcinoma (HCC). In this study, we aimed to investigate the mechanism of lncRNA F11‐AS1 in hepatitis B virus (HBV)–related HCC. The relation of lncRNA F11‐AS1 expression in HBV‐related HCC tissues to prognosis was analysed in silico. Stably HBV‐expressing HepG2.2.15 cells were established to explore the regulation of lncRNA F11‐AS1 by HBx protein, as well as to study the effects of overexpressed lncRNA F11‐AS1 on proliferation, migration, invasion and apoptosis in vitro. Subsequently, the underlying interactions and roles of lncRNA F11‐AS1/miR‐211‐5p/NR1I3 axis in HBV‐related HCC were investigated. Additionally, the influence of lncRNA F11‐AS1 and miR‐211‐5p on tumour growth and metastasis capacity of HepG2.2.15 cells were studied on tumour‐bearing nude mice. Poor expression of lncRNA F11‐AS1 was correlated with poor prognosis in patients with HBV‐related HCC, and its down‐regulation was caused by the HBx protein. lncRNA F11‐AS1 was proved to up‐regulate the NR1I3 expression by binding to miR‐211‐5p. Overexpression of lncRNA F11‐AS1 reduced the proliferation, migration and invasion, yet induced apoptosis of HepG2.2.15 cells in vitro, which could be abolished by overexpression of miR‐211‐5p. Additionally, either lncRNA F11‐AS1 overexpression or miR‐211‐5p inhibition attenuated the tumour growth and metastasis capacity of HepG2.2.15 cells in vivo. Collectively, lncRNA F11‐AS1 acted as a modulator of miR‐211‐5p to positively regulate the expression of NR1I3, and the lncRNA F11‐AS1/miR‐211‐5p/NR1I3 axis participated in HBV‐related HCC progression via interference with the cellular physiology of HCC.     

The lncRNA HNF1A‐AS1 is a negative prognostic factor and promotes tumorigenesis in osteosarcoma

Recent studies have revealed that long noncoding RNA HNF1A‐antisense 1 (HNF1A‐AS1) plays an important role in the development of several human malignancy entities. However, the expression and function of HNF1A‐AS1 in the carcinogenesis and development of osteosarcoma remains unknown. In this study, we detected the HNF1A‐AS1 levels in human osteosarcoma tissues and cell lines by quantitative real‐time polymerase chain reaction (qRT‐PCR), and investigated its role in osteosarcoma by using in vitro assays. Our study showed that HNF1A‐AS1 expression was significantly up‐regulated in human osteosarcoma tissues and cell lines compared with their normal counterparts, and its expression level was positively correlated with the distance metastasis (P = 0.009) and tumour stage (P = 0.019). Moreover, Kaplan–Meier curves with the log‐rank test showed that higher expression of HNF1A‐AS1 conferred a significantly poorer survival and multivariate Cox proportional hazards analysis revealed that HNF1A‐AS1 was an independent risk factor of overall survival. In addition, the expression of HNF1A‐AS1 in serum is correlated with patients’ status and receiver operating characteristic (ROC) curve analysis demonstrated that HNF1A‐AS1 could distinguish patients with osteosarcoma from healthy individuals (the area under curve 0.849, P < 0.001). Furthermore, in vitro knockdown of HNF1A‐AS1 by siRNA significantly inhibited cell proliferation and G₁/S transition, and suppressed migration and invasion by reducing the epithelial‐mesenchymal transition (EMT) program in osteosarcoma cells. Taken together, our data suggested that HNF1A‐AS1 is a novel molecule involved in osteosarcoma progression, which may provide as a potential diagnostic, prognostic biomarker and therapeutic target.     

miR‐150‐5p suppresses the stem cell‐like characteristics of glioma cells by targeting the Wnt/β‐catenin signaling pathway

Glioma is the most common brain tumor malignancy with high mortality and poor prognosis. Emerging evidence suggests that cancer stem cells are the key culprit in the development of cancer. MicroRNAs have been reported to be dysregulated in many cancers, while the mechanism underlying miR‐150‐5p in glioma progression and proportion of stem cells is unclear. The expression levels of miR‐150‐5p and catenin beta 1 (CTNNB1, which encodes β‐catenin) were measured by quantitative real‐time polymerase chain reaction (qRT‐PCR) and western blot. The expression levels of downstream genes of the Wnt/β‐catenin pathway and stem cell markers were detected by qRT‐PCR. Tumorigenesis was investigated by cell viability, colony formation, and tumor growth in vitro and in vivo. The interaction between miR‐150‐5p and β‐catenin was explored via bioinformatics analysis and luciferase activity assay. We found that miR‐150‐5p was downregulated in glioma and its overexpression inhibited cell proliferation, colony formation, and tumor growth. Moreover, miR‐150‐5p directly suppressed CTNNB1 and negatively regulated the abundances of downstream genes of the Wnt/β‐catenin pathway and stem cell markers. Furthermore, miR‐150‐5p expression was decreased and β‐catenin level was enhanced in CD133+ glioma stem cells. Knockdown of miR‐150‐5p contributed to CD133? cells with stem cell‐like phenotype, whereas overexpression of miR‐150‐5p suppressed CD133+ glioma stem cell‐like characteristics. In conclusion, miR‐150‐5p inhibited the progression of glioma by controlling stem cell‐like characteristics via regulating the Wnt/β‐catenin pathway, providing a novel target for glioma treatment.     

LncRNA TNK2‐AS1 regulated ox‐LDL‐stimulated HASMC proliferation and migration via modulating VEGFA and FGF1 expression by sponging miR‐150‐5p

Long non‐coding RNAs (lncRNAs) have been indicated for the regulatory roles in cardiovascular diseases. This study determined the expression of lncRNA TNK2 antisense RNA 1 (TNK2‐AS1) in oxidized low‐density lipoprotein (ox‐LDL)‐stimulated human aortic smooth muscle cells (HASMCs) and examined the mechanistic role of TNK2‐AS1 in the proliferation and migration of HASMCs. Our results demonstrated that ox‐LDL promoted HASMC proliferation and migration, and the enhanced proliferation and migration in ox‐LDL‐treated HASMCs were accompanied by the up‐regulation of TNK2‐AS1. In vitro functional studies showed that TNK2‐AS1 knockdown suppressed cell proliferation and migration of ox‐LDL‐stimulated HASMCs, while TNK2‐AS1 overexpression enhanced HASMC proliferation and migration. Additionally, TNK2‐AS1 inversely regulated miR‐150‐5p expression via acting as a competing endogenous RNA (ceRNA), and the enhanced effects of TNK2‐AS1 overexpression on HASMC proliferation and migration were attenuated by miR‐150‐5p overexpression. Moreover, miR‐150‐5p could target the 3’ untranslated regions of vascular endothelial growth factor A (VEGFA) and fibroblast growth factor 1 (FGF1) to regulate FGF1 and VEGFA expression in HASMCs, and the inhibitory effects of miR‐150‐5p overexpression in ox‐LDL‐stimulated HASMCs were attenuated by enforced expression of VEGFA and FGF1. Enforced expression of VEGFA and FGF1 also partially restored the suppressed cell proliferation and migration induced by TNK2‐AS1 knockdown in ox‐LDL‐stimulated HASMCs, while the enhanced effects of TNK2‐AS1 overexpression on HASMC proliferation and migration were attenuated by the knockdown of VEGFA and FGF1. Collectively, our findings showed that TNK2‐AS1 exerted its action in ox‐LDL‐stimulated HASMCs via regulating VEGFA and FGF1 expression by acting as a ceRNA for miR‐150‐5p.     

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.     

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.     

LncRNA HOXA11‐AS promotes hepatocellular carcinoma progression by repressing miR‐214‐3p

Accumulating studies supported that lncRNAs played important roles in tumorigenesis. LncRNA HOXA11‐AS was a novel lncRNA that has been proved to involved in several tumours. However, the role of HOXA11‐AS in the development of hepatocellular carcinoma (HCC) remains to be explained. In our study, we showed that HOXA11‐AS expression was up‐regulated in the HCC tissues, and the higher expression of HOXA11‐AS was associated with the advanced stage in the HCC samples. In addition, we indicated that the expression of HOXA11‐AS was up‐regulated in HCC cell lines (Hep3B, SMMC‐7721, MHCC97‐H and BEL‐7402) compared with normal liver cell lines (HL‐7702). Overexpression of HOXA11‐AS promoted HCC proliferation and invasion and induced the epithelial‐mesenchymal transition (EMT) and knockdown of HOXA11‐AS suppressed the HCC cell proliferation and invasion. However, we showed that miR‐214‐3p expression was down‐regulated in the HCC tissues and cell lines. Ectopic expression of miR‐214‐3p suppressed HCC cell proliferation and invasion. Furthermore, we indicated that overexpression of HOXA11‐AS decreased the miR‐214‐3p expression and the expression of miR‐214‐3p was negatively related with the HOXA11‐AS expression in HCC samples. Ectopic expression of HOXA11‐AS increased HCC proliferation and invasion and induced EMT through inhibiting miR‐214‐3p expression. These data suggested that HOXA11‐AS/miR‐214‐3p axis was responsible for development of HCC.