MicroRNA‐301b‐3p contributes to tumour growth of human hepatocellular carcinoma by repressing vestigial like family member 4

MicroRNAs (miRNAs) are key regulators in the tumour growth and metastasis of human hepatocellular carcinoma (HCC). Increasing evidence suggests that miR‐301b‐3p functions as a driver in various types of human cancer. However, the expression pattern of miR‐301b‐3p and its functional role as well as underlying molecular mechanism in HCC remain poorly known. Our study found that miR‐301b‐3p expression was significantly up‐regulated in HCC tissues compared to adjacent non‐tumour tissues. Clinical association analysis revealed that the high level of miR‐301b‐3p closely correlated with large tumour size and advanced tumour‐node‐metastasis stages. Importantly, the high miR‐301b‐3p level predicted a prominent poorer overall survival of HCC patients. Knockdown of miR‐301b‐3p suppressed cell proliferation, led to cell cycle arrest at G2/M phase and induced apoptosis of Huh7 and Hep3B cells. Furthermore, miR‐301b‐3p knockdown suppressed tumour growth of HCC in mice. Mechanistically, miR‐301b‐3p directly bond to 3′UTR of vestigial like family member 4 (VGLL4) and negatively regulated its expression. The expression of VGLL4 mRNA was down‐regulated and inversely correlated with miR‐301b‐3p level in HCC tissues. Notably, VGLL4 knockdown markedly repressed cell proliferation, resulted in G2/M phase arrest and promoted apoptosis of HCC cells. Accordingly, VGLL4 silencing rescued miR‐301b‐3p knockdown attenuated HCC cell proliferation, cell cycle progression and apoptosis resistance. Collectively, our results suggest that miR‐301b‐3p is highly expressed in HCC. miR‐301b‐3p facilitates cell proliferation, promotes cell cycle progression and inhibits apoptosis of HCC cells by repressing VGLL4.     

Circular RNA hsa_circRNA_002178 silencing retards breast cancer progression via microRNA‐328‐3p‐mediated inhibition of COL1A1

Circular RNAs (circRNAs) are a group of non‐coding RNAs implicated in the pathogenesis of cancer progression, which exert their functions via regulation of microRNAs (miRNAs) and genes. The present study uses gain‐ and loss‐of‐function approaches to evaluate the functions of hsa_circRNA_002178 in angiogenesis along with energy metabolism and underlying downstream signals. The expression pattern of hsa_circRNA_002178 in clinical breast cancer tissues and its association with prognosis were characterized at first. Next, the energy metabolism and angiogenesis as well as cell viability were evaluated when the expression of hsa_circRNA_002178 in breast cancer cells was knocked down by siRNA. The interaction between hsa_circRNA_002178 and its downstream miR‐328‐3p was identified, followed by the analysis of their functions in regulation of breast cancer cellular behaviours. The target gene of miR‐328‐3p was predicted and verified, followed by identifying its role in the breast cancer progression. Higher expression of hsa_circRNA_002178 shared an association with worse prognosis in breast cancer. The inhibition of hsa_circRNA_002178 resulted in reductions in cell viability, energy metabolism and tube formation ability. Hsa_circRNA_002178 could competitively bind to miR‐328‐3p and down‐regulated its expression. Restoration of miR‐328‐3p eliminated the tumour‐promoting effects of hsa_circRNA_002178. COL1A1, as a target of miR‐328‐3p, could be up‐regulated by overexpression of hsa_circRNA_002178. In vivo experiments further confirmed the inhibition of tumour growth and inflammation by silencing hsa_circRNA_002178 or up‐regulating miR‐328‐3p. Taken together, hsa_circRNA_002178 is highlighted as a promising target for breast cancer due to the anti‐tumour effects achieved by silencing hsa_circRNA_002178.     

IGF2‐derived miR‐483‐3p associated with Hirschsprung's disease by targeting FHL1

HSCR (Hirschsprung's disease) is a serious congenital defect, and the aetiology of it remains unclear. Many studies have highlighted the significant roles of intronic miRNAs and their host genes in various disease, few was mentioned in HSCR although. In this study, miR‐483‐3p along with its host gene IGF2 (Insulin‐like growth factor 2) was found down‐regulated in 60 HSCR aganglionic colon tissues compared with 60 normal controls. FHL1 (Four and a half LIM domains 1) was determined as a target gene of miR‐483‐3p via dual‐luciferase reporter assay, and its expression was at a higher level in HSCR tissues. Here, we study cell migration and proliferation in human 293T and SH‐SY5Y cell lines by performing Transwell and CCK8 assays. In conclusion, the knockdown of miR‐483‐3p and IGF2 both suppressed cell migration and proliferation, while the loss of FHL1 leads to opposite outcome. Furthermore, miR‐483‐3p mimics could rescue the negative effects on cell proliferation and migration caused by silencing IGF2, while the FHL1 siRNA may inverse the function of miR‐483‐3p inhibitor. This study revealed that miR‐483‐3p derived from IGF2 was associated with Hirschsprung's disease by targeting FHL1 and may provide a new pathway to understand the aetiology of HSCR.     

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.     

Long non‐coding RNA SNHG16 promotes proliferation and inhibits apoptosis of diffuse large B‐cell lymphoma cells by targeting miR‐497‐5p/PIM1 axis

The aberrant expression and dysfunction of long non‐coding RNAs (lncRNAs) have been identified as critical factors governing the initiation and progression of different human cancers, including diffuse large B‐cell lymphoma (DLBCL). LncRNA small nucleolar RNA host gene 16 (SNHG16) has been recognized as a tumour‐promoting factor in various types of cancer. However, the biological role of SNHG16 and its underlying mechanism are still unknown in DLBCL. Here we disclosed that SNHG16 was overexpressed in DLBCL tissues and the derived cell lines. SNHG16 knockdown significantly suppressed cell proliferation and cell cycle progression, and it induced apoptosis of DLBCL cells in vitro. Furthermore, silencing of SNHG16 markedly repressed in vivo growth of OCI‐LY7 cells. Mechanistically, SNHG16 directly interacted with miR‐497‐5p by acting as a competing endogenous RNA (ceRNA) and inversely regulated the abundance of miR‐497‐5p in DLBCL cells. Moreover, the proto‐oncogene proviral integration site for Moloney murine leukaemia virus 1 (PIM1) was identified as a novel direct target of miR‐497‐5p. SNHG16 overexpression rescued miR‐497‐5p‐induced down‐regulation of PIM1 in DLBCL cells. Importantly, restoration of PIM1 expression reversed SNHG16 knockdown‐induced inhibition of proliferation, G0/G1 phase arrest and apoptosis of OCI‐LY7 cells. Our study suggests that the SNHG16/miR‐497‐5p/PIM1 axis may provide promising therapeutic targets for DLBCL progression.     

Epigenetic silenced miR‐125a‐5p could be self‐activated through targeting Suv39H1 in gastric cancer

Emerging evidence suggests that microRNAs (miRNAs) serve an important role in tumorigenesis and development. Although the low expression of miR‐125a‐5p in gastric cancer has been reported, the underlying mechanism remains unknown. In the current study, the low expression of miR‐125a‐5p in gastric cancer was verified in paired cancer tissues and adjacent non‐tumour tissues. Furthermore, the GC islands in the miR‐125a‐5p region were hypermethylated in the tumour tissues. And the hypermethylation was negatively correlated with the miR‐125a‐5p expression. Target gene screening showed that the histone methyltransferase Suv39H1 was one of the potential target genes. In vitro studies showed that miR‐125a‐5p could directly suppress the Suv39H1 expression and decrease the H3K9me3 levels. On the other hand, the Suv39H1 could induce demethylation of miR‐125a‐5p, resulting in re‐activation of miR‐125a‐5p. What is more, overexpessing miR‐125a‐5p could also self‐activate the silenced miR‐125a‐5p in gastric cancer cells, which suppressed cell migration, invasion and proliferation in vitro and inhibited cancer progression in vivo. Thus, we uncovered here that the epigenetic silenced miR‐125a‐5p could be self‐activated through targeting Suv39H1 in gastric cancer, suggesting that miR‐125a‐5p might be not only the potential prognostic value as a tumour biomarker but also potential therapeutic targets in gastric cancer.     

miR‐515‐5p controls cancer cell migration through MARK4 regulation

Here, we show that miR‐515‐5p inhibits cancer cell migration and metastasis. RNA‐seq analyses of both oestrogen receptor receptor‐positive and receptor‐negative breast cancer cells overexpressing miR‐515‐5p reveal down‐regulation of NRAS, FZD4, CDC42BPA, PIK3C2B and MARK4 mRNAs. We demonstrate that miR‐515‐5p inhibits MARK4 directly 3′ UTR interaction and that MARK4 knock‐down mimics the effect of miR‐515‐5p on breast and lung cancer cell migration. MARK4 overexpression rescues the inhibitory effects of miR‐515‐5p, suggesting miR‐515‐5p mediates this process through MARK4 down‐regulation. Furthermore, miR‐515‐5p expression is reduced in metastases compared to primary tumours derived from both in vivo xenografts and samples from patients with breast cancer. Conversely, miR‐515‐5p overexpression prevents tumour cell dissemination in a mouse metastatic model. Moreover, high miR‐515‐5p and low MARK4 expression correlate with increased breast and lung cancer patients' survival, respectively. Taken together, these data demonstrate the importance of miR‐515‐5p/MARK4 regulation in cell migration and metastasis across two common cancers.     

miR‐516a‐3p inhibits breast cancer cell growth and EMT by blocking the Pygo2/Wnt signalling pathway

miR‐516a‐3p has been reported to play a suppressive role in several types of human tumours. However, the expression level, biological function and fundamental mechanisms of miR‐516a‐3p in breast cancer remain unclear. In the present study, we found that miR‐516a‐3p expression was down‐regulated and Pygopus2 (Pygo2) expression was up‐regulated in human breast cancer tissues and cells. Through analysing the clinicopathological characteristics, we demonstrated that low miR‐516a‐3p expression or positive Pygo2 expression was a predictor of poor prognosis for patients with breast cancer. The results of a dual luciferase reporter assay and Western blot analysis indicated that Pygo2 was a target gene of miR‐516a‐3p. Moreover, overexpression of miR‐516a‐3p inhibited cell growth, migration and invasion as well as epithelial‐mesenchymal transition (EMT) of breast cancer cells, whereas reduced miR‐516a‐3p expression promoted breast cancer cell growth, migration, invasion and EMT. Furthermore, we showed that miR‐516a‐3p suppressed cell proliferation, metastasis and EMT of breast cancer cells by inhibiting Pygo2 expression. We confirmed that miR‐516a‐3p exerted an anti‐tumour effect by inhibiting the activation of the Wnt/β‐catenin pathway. Finally, xenograft tumour models were used to show that miR‐516a‐3p inhibited breast cancer cell growth and EMT via suppressing the Pygo2/Wnt signalling pathway. Taken together, these results show that miR‐516a‐3p inhibits breast cancer cell growth, metastasis and EMT by blocking the Pygo2/ Wnt/β‐catenin pathway.     

miR‐193b availability is antagonized by LncRNA‐SNHG7 for FAIM2‐induced tumour progression in non‐small cell lung cancer

Objectives

Long non‐coding RNAs have identified to involve into the tumour cell proliferation, apoptosis and metastasis. We previously found that up‐regulated LncRNA‐SNHG7 (SNHG7) positively correlated to the Fas apoptosis inhibitory molecule 2 (FAIM2) in lung cancer cells with unclear mechanism.

Methods

Non‐small cell lung cancer (NSCLC) and relative normal tissues (n = 25) were collected. The SNHG7 expression and function in NSCLC was determined. The SNHG7‐miR 193b‐FAIM2 network was analysed in vitro and vivo.

Results

We reported that oncogene SNHG7 predicted a poor clinical outcome and functioned as competitive endogenous RNA (ceRNA) antagonized microRNA‐193b (miR‐193b) to up‐regulate the FAIM2 level in NSCLC. Bioinformatic analysis predicted that SNHG7 harboured miR‐193b‐binding sites, and we found decreased miR‐193b levels in NSCLC tissues when compared to relative normal tissues. Luciferase assays indicated that overexpression of miR‐193b inhibited the Ruc expression of plasmid with miR‐193b‐binding sites of SNHG7 in a dose‐dependent manner. Ectopically expressed SNHG7 also as a molecular sponge sequestered endogenous miR‐193b. Besides, FAIM2 was found to be directly targeted by miR‐193b. The restoration of miR‐193b levels in NSCLC cell lines A549 and H125 suppressed the expression of FAIM2 and related tumour proliferation, metastasis and induced apoptosis. However, forced expression of SNHG7 could down‐regulate miR‐193b to elevate the FAIM2 level of tumour cells, leading to impaired miR‐193b/FAIM2‐induced tumour progression. Knockdown of SNHG7 in vivo significantly delayed the tumour growth with decreased tumour volume, which accompanied with enhanced miR‐193b expression and reduced FAIM2 levels.

Conclusion

The results indicated that miR‐193b is indispensible for the ceRNA role of SNHG7 in FAIM2‐supported tumourigenesis of lung cancer.     

Loss‐of‐function of miR‐142 by hypermethylation promotes TGF‐β‐mediated tumour growth and metastasis in hepatocellular carcinoma

Objectives

Hypermethylation‐induced epigenetic silencing of tumour suppressor genes (TSGs) are frequent events during carcinogenesis. MicroRNA‐142 (miR‐142) is found to be dysregulated in cancer patients to participate into tumour growth, metastasis and angiogenesis. However, the tumour suppressive role of miR‐142 and the status of methylation are not fully understood in hepatocellular carcinoma (HCC).

Methods

Hepatocellular carcinoma tissues and corresponding non‐neoplastic tissues were collected. The expression and function of miR‐142 and TGF‐β in two HCC cell lines were determined. The miRNA‐mRNA network of miR‐142 was analysed in HCC cell lines.

Results

We found that the miR‐142 expression was reduced in tumour tissues and two HCC cell lines HepG2 and SMMC7721, which correlated to higher TNM stage, metastasis and differentiation. Moreover, miR‐142 was identified to directly target and inhibit transforming growth factor β (TGF‐β), leading to decreased cell vitality, proliferation, EMT and the ability of pro‐angiogenesis in TGF‐β‐dependent manner. Interestingly, the status of methylation of miR‐142 was analysed and the results found the hypermethylated miR‐142 in tumour patients and cell lines. The treatment of methylation inhibitor 5‐Aza could restore the expression of miR‐142 to suppress the TGF‐β expression, which impaired TGF‐β‐induced tumour growth.

Conclusion

These findings implicated that miR‐142 was a tumour suppressor gene in HCC and often hyermethylated to increase TGF‐β‐induced development of hepatocellular carcinoma.

     

Up‐regulation of ZFAS1 indicates dismal prognosis for cholangiocarcinoma and promotes proliferation and metastasis by modulating USF1 via miR‐296‐5p

LncRNAs has been demonstrated to modulate neoplastic development by modulating downstream miRNAs and functional genes. In this study, we aimed to detect the interaction among lncRNA ZFAS1 miR‐296‐5p and USF1. We explored the proliferation, migration and invasion of cholangiocarcinoma. The differentially expressed ZFAS1 was discovered in both tissues and cell lines by qRT‐PCR. The targeting relationship between miR‐296‐5p and ZFAS1 or USF1 was validated by dual‐luciferase assay. The impact of ZFAS1 on CCA cell proliferation was observed by CCK‐8 assay. The protein expression of USF1 was determined by Western blot. The effects of ZFAS1, miR‐296‐5p and USF1 on tumour growth were further confirmed using xenograft model. LncRNA ZFAS1 expression was relatively up‐regulated in tumour tissues and cells while miR‐296‐5p was significantly down‐regulated. Knockdown of ZFAS1 significantly suppressed tumour proliferation, migration, invasion and USF1 expression. Overexpressed miR‐296‐5p suppressed cell proliferation and metastasis. Knockdown of USF1 inhibited cell proliferation and metastasis and xenograft tumour growth. In conclusion, ZFAS1 might promote cholangiocarcinoma proliferation and metastasis by modulating USF1 via miR‐296‐5p.     

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

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

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.     

MicroRNA‐551b‐3p inhibits tumour growth of human cholangiocarcinoma by targeting Cyclin D1

MicroRNAs (miRNAs) are powerful regulators in the tumorigenesis of cholangiocarcinoma (CCA). Previous studies report that miR‐551b‐3p acts as an oncogenic factor in ovarian cancer, but plays a tumour suppressive role in gastric cancer. However, the expression pattern and potential function of miR‐551b‐3p were still unclear in CCA. Therefore, this study aimed to explore the expression of miR‐551b‐3p and its role as well as molecular mechanism in CCA. Analysis of TCGA dataset suggested that miR‐551b‐3p was under‐expressed in CCA tissues compared to normal bile duct tissues. Furthermore, our data confirmed the decreased levels of miR‐551b‐3p in CCA samples and cell lines. Interestingly, TCGA data suggested that low miR‐551b‐3p level indicated reduced overall survival of CCA patients. Gain‐ and loss‐of‐function experiments found that miR‐551b‐3p inhibited the proliferation, G1‐S phase transition and induced apoptosis of CCA cells. In vivo experiments revealed that ectopic expression of miR‐551b‐3p inhibited tumour growth of CCA in mice. Further investigation demonstrated that miR‐551b‐3p directly bond to the 3′‐UTR of Cyclin D1 (CCND1) mRNA and negatively regulated the abundance of CCND1 in CCA cells. An inverse correlation between miR‐551b‐3p expression and the level of CCND1 mRNA was detected in CCA tissues from TCGA dataset. Notably, CCND1 knockdown showed similar effects to miR‐551b‐3p overexpression in HuCCT‐1 cells. CCND1 restoration rescued miR‐551b‐3p‐induced inhibition of proliferation, G1 phase arrest and apoptosis in HuCCT‐1 cells. In summary, miR‐551b‐3p inhibits the expression of CCND1 to suppress CCA cell proliferation and induce apoptosis, which may provide a theoretical basis for improving CCA treatment.