MicroRNA‐148a‐3p suppresses epithelial‐to‐mesenchymal transition and stemness properties via Wnt1‐mediated Wnt/β‐catenin pathway in pancreatic cancer

Although miR‐148a‐3p has been reported to function as a tumour suppressor in various cancers, the molecular mechanism of miR‐148a‐3p in regulating epithelial‐to‐mesenchymal transition (EMT) and stemness properties of pancreatic cancer (PC) cells remains to be elucidated. In the present study, we demonstrated that miR‐148a‐3p expression was remarkably down‐regulated in PC tissues and cell lines. Moreover, low expression of miR‐148a‐3p was associated with poorer overall survival (OS) in patients with PC. In vitro, gain‐of‐function and loss‐of‐function experiments showed that miR‐148a‐3p suppressed EMT and stemness properties as well as the proliferation, migration and invasion of PC cells. A dual‐luciferase reporter assay demonstrated that Wnt1 was a direct target of miR‐148a‐3p, and its expression was inversely associated with miR‐148a‐3p in PC tissues. Furthermore, miR‐148a‐3p suppressed the Wnt/β‐catenin pathway via down‐regulation of Wnt1. The effects of ectopic miR‐148a‐3p were rescued by Wnt1 overexpression. These biological functions of miR‐148a‐3p in PC were also confirmed in a nude mouse xenograft model. Taken together, these findings suggest that miR‐148a‐3p suppresses PC cell proliferation, invasion, EMT and stemness properties via inhibiting Wnt1‐mediated Wnt/β‐catenin pathway and could be a potential prognostic biomarker as well as a therapeutic target in PC.     

Down‐regulated LINC00115 inhibits prostate cancer cell proliferation and invasion via targeting miR‐212‐5p/FZD5/Wnt/β‐catenin axis

Prostate cancer is the second most frequent malignancy in men worldwide, and its incidence is increasing. Therefore, it is urgently required to clarify the underlying mechanisms of prostate cancer. Although the long non‐coding RNA LINC00115 was identified as an oncogene in several cancers, the expression and function of LINC00115 in prostate cancer have not been explored. Our results showed that LINC00115 was significantly up‐regulated in prostate cancer tissues, which was significantly associated with a poor prognosis for prostate cancer patients. Functional studies showed that knockdown LINC00115 inhibited cell proliferation and invasion. In addition, LINC00115 served as a competing endogenous RNA (ceRNA) through sponging miR‐212‐5p to release Frizzled Family Receptor 5 (FZD5) expression. The expression of miR‐212‐5p was noticeably low in tumour tissues, and FZD5 expression level was down‐regulated with the knockdown of LINC00115. Knockdown LINC00115 inhibited the Wnt/β‑catenin signalling pathway by inhibiting the expression of FZD5. Rescue experiments further showed that LINC00115 inhibits prostate cancer cell proliferation and invasion via targeting miR‐212‐5p/ FZD5/ Wnt/β‐catenin axis. The present study provided clues that LINC00115 may be a promising novel therapeutic target for prostate cancer patients.     

Knockdown of circular RNA VANGL1 inhibits TGF‐β‐induced epithelial‐mesenchymal transition in melanoma cells by sponging miR‐150‐5p

Melanoma is one of the most aggressive and life‐threatening skin cancers, and in this research, we aimed to explore the functional role of circular RNA VANGL1 (circVANGL1) in melanoma progression. The expression levels of circVANGL1 were observed to be significantly increased in clinical melanoma tissues and cell lines. Moreover, circVANGL1 knockdown suppressed, while circVANGL1 overexpression promoted the proliferation, migration and invasion abilities of melanoma cells. Further investigations confirmed the direct binding relation between circVANGL1 and miR‐150‐5p in melanoma, and restoration of miR‐150‐5p blocked the effects of circVANGL1 overexpression in melanoma cells. We further found that circVANGL1 was up‐regulated by TGF‐β treatment, and the enhanced EMT of TGF‐β‐treated melanoma cells was blocked by circVANGL1 knockdown. In conclusion, these results indicated that circVANGL1 might serve as a promising therapeutic target for melanoma.     

MiR‐503 suppresses fibroblast activation and myofibroblast differentiation by targeting VEGFA and FGFR1 in silica‐induced pulmonary fibrosis

Inhalation and deposition of crystalline silica particles in the lung can cause pulmonary fibrosis, then leading to silicosis. Given the paucity of effective drugs for silicosis, new insights for understanding the mechanisms of silicosis, including lung fibroblast activation and myofibroblast differentiation, are essential to explore therapeutic strategies. Our previous research showed that the up‐regulation of miR‐503 alleviated silica‐induced pulmonary fibrosis in mice. In this study, we investigated whether miR‐503 can regulate the TGF‐β1‐induced effects in lung fibroblasts. Mimic‐based strategies aiming at up‐regulating miR‐503 were used to discuss the function of miR‐503 in vivo and in vitro. We found that the expression level of miR‐503 was decreased in fibroblasts stimulated by TGF‐β1, and the up‐regulation of miR‐503 reduced the release of fibrotic factors and inhibited the migration and invasion abilities of fibroblasts. Combined with the up‐regulation of miR‐503 in a mouse model of silica‐induced pulmonary fibrosis, we revealed that miR‐503 mitigated the TGF‐β1‐induced effects in fibroblasts by regulating VEGFA and FGFR1 and then affecting the MAPK/ERK signalling pathway. In conclusion, miR‐503 exerted protective roles in silica‐induced pulmonary fibrosis and may represent a novel and potent candidate for therapeutic strategies in silicosis.     

Polydatin inhibits ZEB1‐invoked epithelial‐mesenchymal transition in fructose‐induced liver fibrosis

High fructose intake is a risk factor for liver fibrosis. Polydatin is a main constituent of the rhizome of Polygonum cuspidatum, which has been used in traditional Chinese medicine to treat liver fibrosis. However, the underlying mechanisms of fructose‐driven liver fibrosis as well as the actions of polydatin are not fully understood. In this study, fructose was found to promote zinc finger E‐box binding homeobox 1 (ZEB1) nuclear translocation, decrease microRNA‐203 (miR‐203) expression, increase survivin, activate transforming growth factor β1 (TGF‐β1)/Smad signalling, down‐regulate E‐cadherin, and up‐regulate fibroblast specific protein 1 (FSP1), vimentin, N‐cadherin and collagen I (COL1A1) in rat livers and BRL‐3A cells, in parallel with fructose‐induced liver fibrosis. Furthermore, ZEB1 nuclear translocation‐mediated miR‐203 low‐expression was found to target survivin to activate TGF‐β1/Smad signalling, causing the EMT in fructose‐exposed BRL‐3A cells. Polydatin antagonized ZEB1 nuclear translocation to up‐regulate miR‐203, subsequently blocked survivin‐activated TGF‐β1/Smad signalling, which were consistent with its protection against fructose‐induced EMT and liver fibrosis. These results suggest that ZEB1 nuclear translocation may play an essential role in fructose‐induced EMT in liver fibrosis by targeting survivin to activate TGF‐β1/Smad signalling. The suppression of ZEB1 nuclear translocation by polydatin may be a novel strategy for attenuating the EMT in liver fibrosis associated with high fructose diet.     

A disintegrin and metalloproteinase 8 induced epithelial‐mesenchymal transition to promote the invasion of colon cancer cells via TGF‐β/Smad2/3 signalling pathway

A disintegrin and metalloproteinase 8 (ADAM8) protein is a multi‐domain transmembrane glycoprotein which involves in extracellular matrix remodelling, cell adhesion, invasion and migration. ADAM8 and epithelial‐mesenchymal transition (EMT) play an important role in tumour invasion has been well established. However, the interaction between ADAM8 and EMT has remained unclear. The data of colon cancer patients obtained from TCGA (The Cancer Genome Atlas) and GTEx (Genotype‐Tissue Expression Project) were analysed by the bioinformatics research method. The expression of ADAM8 in colon cancer cells was up‐regulated and down‐regulated by transfecting with the expression plasmid and small interfering RNA, respectively. Transwell invasion assay, immunohistochemistry, immunocytochemistry, Western blotting and qRT‐PCR were utilized to study the effect of ADAM8 on colon cancer cell''s EMT and its related mechanisms. Analysis of TCGA and GTEx data revealed that ADAM8 was linked to poor overall survival in colon cancer patients. Besides, ADAM8 was correlated with multiple EMT biomarkers (E‐cadherin, N‐cadherin, Vimentin, Snail2 and ZEB2). In vitro, we also proved that the up‐regulation of ADAM8 could promote EMT effect and enhance the invasive ability of colon cancer cells. On the contrary, the down‐regulation of ADAM8 in colon cancer cells attenuated these effects above. Further studies suggested that ADAM8 modulated EMT on colon cancer cells through TGF‐β/Smad2/3 signalling pathway. Our research suggested that ADAM8 could be a potential biomarker for the prognosis of colon cancer and induced EMT to promote the invasion of colon cancer cells via activating TGF‐β/Smad2/3 signalling pathway.     

circRNA 001306 enhances hepatocellular carcinoma growth by up‐regulating CDK16 expression via sponging miR‐584‐5p

Circular RNAs (circRNAs) have been demonstrated to play important roles in cancer progress. However, the roles in hepatocellular carcinoma (HCC) are still unclear. Here, we found has_circRNA_001306 (circ_1306) was up‐regulated in HCC tissues and cell lines. Knockdown the expression circ_1306 significantly suppressed HCC cell proliferation and induced the cell apoptosis in vitro and in vivo. Furthermore, we identified circ_1306 could up‐regulate the expression of CDK16 by sponging miR‐584‐5p. The expression of miR‐584‐5p was decreased, and the expression of CDK16 was increased in HCC tissues and cell lines. Meanwhile, either knockdown of miR‐584‐5p or overexpression of CDK16 could suppress the HCC cell proliferation. In vivo, overexpression of miR‐584‐5p or knockdown of circ_1306 could inhibit the expression of CDK16, and suppress tumour growth. Altogether, our findings suggested that circ_1306 could promoter HCC progress by miR‐584‐5p/CDK16 axis, which provided a novel marker for HCC diagnosis and treatment.     

Circ_0067835 sponges miR‐324‐5p to induce HMGA1 expression in endometrial carcinoma cells

Endometrial cancer is a common gynaecological malignant tumour among women across the world. Circular RNAs (circRNAs) are a novel kind of non‐coding RNAs, and they can play a crucial role in multiple cancers. Nevertheless, the mechanisms of circRNAs in regulating gene expression in endometrial cancer are still unclear. Here, our work sought to focus on the role that circ_0067835 exert in progression and development of endometrial cancer cells. We observed circ_0067835 was markedly elevated in endometrial cancer. Then, changes in endometrial cancer cell (RL95‐2 and HEC‐1B) function were determined after circ_0067835 knockdown. Loss‐of‐functional assays revealed that circ_0067835 down‐regulation significantly repressed RL95‐1 and HEC‐1B cell proliferation, migration and invasion. Bioinformatics analysis, luciferase reporter experiment and RNA pull‐down assay were employed to predict and validate circ_0067835 can bind to miR‐324‐5p. Increase in miR‐324‐5p remarkably depressed the proliferation, migration and invasion of endometrial cancer cells via inhibiting high mobility group A1 (HMGA1). HMGA1 is identified as a vital prognostic biomarker in endometrial cancer. Currently, we reported circ_0067835 was positively correlated with HMGA1 in endometrial cancer. We implied that circ_0067835 was capable of sponging miR‐324‐5p and inducing its downstream target HMGA1 in vitro and in vivo. In conclusion, circ_0067835 can compete with miR‐324‐5p, resulting in HMGA1 up‐regulation, and therefore induce the development of endometrial cancer.     

DEK‐targeting aptamer DTA‐64 attenuates bronchial EMT‐mediated airway remodelling by suppressing TGF‐β1/Smad,MAPK and PI3K signalling pathway in asthma

This study is to investigate the inhibitory effects and mechanisms of DEK‐targeting aptamer (DTA‐64) on epithelial mesenchymaltransition (EMT)‐mediated airway remodelling in mice and human bronchial epithelial cell line BEAS‐2B. In the ovalbumin (OVA)‐induced asthmatic mice, DTA‐64 significantly reduced the infiltration of eosinophils and neutrophils in lung tissue, attenuated the airway resistance and the proliferation of goblet cells. In addition, DTA‐64 reduced collagen deposition, transforming growth factor 1 (TGF‐β1) level in BALF and IgE levels in serum, balanced Th1/Th2/Th17 ratio, and decreased mesenchymal proteins (vimentin and α‐SMA), as well as weekend matrix metalloproteinases (MMP‐2 and MMP‐9) and NF‐κB p65 activity. In the in vitro experiments, we used TGF‐β1 to induce EMT in the human epithelial cell line BEAS‐2B. DEK overexpression (ovDEK) or silencing (shDEK) up‐regulated or down‐regulated TGF‐β1 expression, respectively, on the contrary, TGF‐β1 exposure had no effect on DEK expression. Furthermore, ovDEK and TGF‐β1 synergistically promoted EMT, whereas shDEK significantly reduced mesenchymal markers and increased epithelial markers, thus inhibiting EMT. Additionally, shDEK inhibited key proteins in TGF‐β1‐mediated signalling pathways, including Smad2/3, Smad4, p38 MAPK, ERK1/2, JNK and PI3K/AKT/mTOR. In conclusion, the effects of DTA‐64 against EMT of asthmatic mice and BEAS‐2B might partially be achieved through suppressing TGF‐β1/Smad, MAPK and PI3K signalling pathways. DTA‐64 may be a new therapeutic option for the management of airway remodelling in asthma patients.     

MicroRNA‐411‐3p inhibits bleomycin‐induced skin fibrosis by regulating transforming growth factor‐β/Smad ubiquitin regulatory factor‐2 signalling

Skin fibrosis, which is characterized by fibroblast proliferation and increased extracellular matrix, has no effective treatment. An increasing number of studies have shown that microRNAs (miRNAs/miRs) participate in the mechanism of skin fibrosis, such as in limited cutaneous systemic sclerosis and pathological scarring. The objective of the present study was to determine the role of miR‐411‐3p in bleomycin (BLM)‐induced skin fibrosis and skin fibroblast transformation. Using Western blot analysis and real‐time quantitative polymerase chain reaction assess the expression levels of miR‐411‐3p, collagen (COLI) and transforming growth factor (TGF)‐β/Smad ubiquitin regulatory factor (Smurf)‐2/Smad signalling factors both in vitro and in vivo with or without BLM. To explore the regulatory relationship between miR‐411‐3p and Smurf2, we used the luciferase reporter assay. Furthermore, miR‐411‐3p overexpression was identified in vitro and in vivo via transfection with Lipofectamine 2000 reagent and injection. Finally, we tested the dermal layer of the skin using haematoxylin and eosin and Van Gieson''s staining. We found that miR‐411‐3p expression was decreased in bleomycin (BLM)‐induced skin fibrosis and fibroblasts. However, BLM accelerated transforming growth factor (TGF)‐β signalling and collagen production. Overexpression of miR‐411‐3p inhibited the expression of collagen, F‐actin and the TGF‐β/Smad signalling pathway factors in BLM‐induced skin fibrosis and fibroblasts. In addition, miR‐411‐3p inhibited the target Smad ubiquitin regulatory factor (Smurf)‐2. Furthermore, Smurf2 was silenced, which attenuated the expression of collagen via suppression of the TGF‐β/Smad signalling pathway. We demonstrated that miR‐411‐3p exerts antifibrotic effects by inhibiting the TGF‐β/Smad signalling pathway via targeting of Smurf2 in skin fibrosis.     

Naa10p and IKKα interaction regulates EMT in oral squamous cell carcinoma via TGF‐β1/Smad pathway

Epithelial‐mesenchymal transition (EMT) has been contributed to increase migration and invasion of cancer cells. However, the correlate of Naa10p and IKKα with EMT in oral squamous cell carcinoma (OSCC) is not yet fully understood. In our present study, we found N‐α‐acetyltransferase 10 protein (Naa10p) and IκB kinase α (IKKα) were abnormally abundant in oral squamous cell carcinoma (OSCC). Bioinformatic results indicate that the expression of Naa10p and IKKα is correlated with TGF‐β1/Smad and EMT‐related molecules. The Transwell migration, invasion, qRT‐PCR and Western blot assay indicated that Naa10p repressed OSCC cell migration, invasion and EMT, whereas IKKα promoted TGF‐β1–mediated OSCC cell migration, invasion and EMT. Mechanistically, Naa10p inhibited IKKα activation of Smad3 through the interaction with IKKα directly in OSCC cells after TGF‐β1 stimulation. Notably, knockdown of Naa10p reversed the IKKα‐induced change in the migration, invasion and EMT‐related molecules in OSCC cells after TGF‐β1 stimulation. These findings suggest that Naa10p interacted with IKKα mediates EMT in OSCC cells through TGF‐β1/Smad, a novel pathway for preventing OSCC.     

CircHivep2 contributes to microglia activation and inflammation via miR‐181a‐5p/SOCS2 signalling in mice with kainic acid‐induced epileptic seizures

Epilepsy is a chronic brain disease characterized by recurrent seizures. Circular RNA (circRNA) is a novel family of endogenous non‐coding RNAs that have been proposed to regulate gene expression. However, there is a lack of data on the role of circRNA in epilepsy. In this study, the circRNA profiles were evaluated by microarray analysis. In total, 627 circRNAs were up‐regulated, whereas 892 were down‐regulated in the hippocampus in mice with kainic acid (KA)‐induced epileptic seizures compared with control. The expression of circHivep2 was significantly down‐regulated in hippocampus tissues of mice with KA‐induced epileptic seizures and BV‐2 microglia cells upon KA treatment. Bioinformatics analysis predicted that circHivep2 interacts with miR‐181a‐5p to regulate SOCS2 expression, which was validated using a dual‐luciferase reporter assay. Moreover, overexpression of circHivep2 significantly inhibited KA‐induced microglial activation and the expression of inflammatory factors in vitro, which was blocked by miR‐181a‐5p, whereas circHivep2 knockdown further induced microglia cell activation and the release of pro‐inflammatory proteins in BV‐2 microglia cells after KA treatment. The application of circHivep2+ exosomes derived from adipose‐derived stem cells (ADSCs) exerted significant beneficial effects on the behavioural seizure scores of mice with KA‐induced epilepsy compared to control exosomes. The circHivep2+ exosomes also inhibited microglial activation, the expression of inflammatory factors, and the miR‐181a‐5p/SOCS2 axis in vivo. Our results suggest that circHivep2 regulates microglia activation in the progression of epilepsy by interfering with miR‐181a‐5p to promote SOCS2 expression, indicating that circHivep2 may serve as a therapeutic tool to prevent the development of epilepsy.     

Down‐regulated HDAC3 elevates microRNA‐495‐3p to restrain epithelial‐mesenchymal transition and oncogenicity of melanoma cells via reducing TRAF5

MicroRNAs (miRNAs) are emerging biomarkers in biological processes and the role of miR‐495‐3p has been identified in melanoma, while the detailed molecular mechanisms remain to be further explored. We aim to explore the effect of histone deacetylase 3 (HDAC3) and miR‐495‐3p on epithelial‐mesenchymal transition (EMT) and oncogenicity of melanoma cells by regulating tumour necrosis factor receptor‐associated factor 5 (TRAF5). Levels of HDAC3, miR‐495‐3p and TRAF5 in melanoma tissues and pigmented nevus tissues were determined, and the predictive roles of HDAC3 and miR‐495‐3p in prognosis of melanoma patients were measured. The melanoma cells were screened and transfected with relative oligonucleotides and plasmids, and the expression of HDAC3, miR‐495‐3p and TRAF5, and phenotypes of melanoma cells were gauged by a series of assays. The relations between HDAC3 and miR‐495‐3p, and between miR‐495‐3p and TRAF5 were confirmed. HDAC3 and TRAF5 were increased while miR‐495‐3p was decreased in melanoma cells and tissues, and the low expression of miR‐495‐3p as well as high expression of HDAC3 indicated a poor prognosis of melanoma patients. Inhibited HDAC3 elevated miR‐495‐3p to suppress EMT and oncogenicity of melanoma cells by reducing TRAF5. HDAC3 particularly bound to miR‐495‐3p and TRAF5 was the target gene of miR‐495‐3p. Our results revealed that down‐regulated HDAC3 elevates miR‐495‐3p to suppress malignant phenotypes of melanoma cells by inhibiting TRAF5, thereby repressing EMT progression of melanoma cells. This study may provide novel targets for melanoma treatment.     

LncRNA ARAP1‐AS2 promotes high glucose‐induced human proximal tubular cell injury via persistent transactivation of the EGFR by interacting with ARAP1

The persistent transactivation of epidermal growth factor receptor (EGFR) causes subsequent activation of the TGF‐β/Smad3 pathway, which is closely associated with fibrosis and cell proliferation in diabetic nephropathy (DN), but the exact mechanism of persistent EGFR transactivation in DN remains unclear. ARAP1, a susceptibility gene for type 2 diabetes, can regulate the endocytosis and ubiquitination of membrane receptors, but the effect of ARAP1 and its natural antisense long non‐coding RNA (lncRNA), ARAP1‐AS2, on the ubiquitination of EGFR in DN is not clear. In this study, we verified that the expression of ARAP1 and ARAP1‐AS2 was significantly up‐regulated in high glucose‐induced human proximal tubular epithelial cells (HK‐2 cells). Moreover, we found that overexpression or knockdown of ARAP1‐AS2 could regulate fibrosis and HK‐2 cell proliferation through EGFR/TGF‐β/Smad3 signalling. RNA pulldown assays revealed that ARAP1‐AS2 directly interacts with ARAP1. Coimmunoprecipitation, dual‐immunofluorescence and ubiquitination assays showed that ARAP1 may maintain persistent EGFR activation by reducing EGFR ubiquitination through competing with Cbl for CIN85 binding. Taken together, our results suggest that the lncRNA ARAP1‐AS2 may promote high glucose‐induced proximal tubular cell injury via persistent EGFR/TGF‐β/Smad3 pathway activation by interacting with ARAP1.     

circ_SEPT9, a newly identified circular RNA,promotes oral squamous cell carcinoma progression through miR‐1225/PKN2 axis

Circular RNAs (circRNAs) represent a newly discovered class of endogenous non‐coding RNAs which are widely expressed and play important roles in disease progression. However, the function of circRNAs in oral squamous cell carcinoma (OSCC) still remains largely unknown. In this research, we found that circ_SEPT9 was highly expressed in OSCC cell lines and tumour tissues. Results showed that circ_SEPT9 promoted OSCC proliferation and tumour growth. And, circ_SEPT9 also enhanced the migration and invasion of OSCC cells. Mechanically, we found that circ_SEPT9 acted as a sponge for miR‐1225 to rescue PKN2 expression in OSCC cells. Inhibition of circ_SEPT9/miR‐1225/PKN2 pathway could effectively block the proliferation and metastasis of OSCC cells. Our study provides strong evidence that circ_SEPT9/miR‐1225/PKN2 axis is a promising target for OSCC treatment.     

HIF‐1α‐induced up‐regulation of microRNA‐126 contributes to the effectiveness of exercise training on myocardial angiogenesis in myocardial infarction rats

Exercise training (ET) is a non‐drug natural rehabilitation approach for myocardial infarction (MI). Among the numerous beneficial effects of ET, myocardial angiogenesis is indispensable. In the present study, we investigated the role and mechanism of HIF‐1α and miR‐126 in ET‐induced MI myocardial angiogenesis which may provide new insights for MI treatment. Rat model of post‐MI and human umbilical vein endothelial cells (HUVECs) were employed for our research. Histomorphology, immunohistochemistry, quantitative real‐time PCR, Western blotting and small‐interfering RNA (siRNA) transfection were applied to evaluate the morphological, functional and molecular mechanisms. In vivo results showed that 4‐week ET could significantly increase the expression of HIF‐1α and miR‐126 and reduce the expression of PIK3R2 and SPRED1, while 2ME2 (HIF‐1α inhibitor) partially attenuated the effect of ET treatment. In vitro results showed that HIF‐1α could trigger expression of miR‐126 in HUVECs in both normoxia and hypoxia, and miR‐126 may be involved in the tube formation of HUVECs under hypoxia through the PI3K/AKT/eNOS and MAPK signalling pathway. In conclusion, we revealed that HIF‐1α, whose expression experiences up‐regulation during ET, could function as an upstream regulator to miR‐126, resulting in angiogenesis promotion through the PI3K/AKT/eNOS and MAPK signalling pathway and subsequent improvement of the MI heart function.     

MTHFD2 promotes tumorigenesis and metastasis in lung adenocarcinoma by regulating AKT/GSK‐3β/β‐catenin signalling

Recent studies have demonstrated that one‐carbon metabolism plays a significant role in cancer development. Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2), a mitochondrial enzyme of one‐carbon metabolism, has been reported to be dysregulated in many cancers. However, the specific role and mechanism of MTHFD2 in lung adenocarcinoma (LUAD) still remains unclear. In this study, we evaluated the clinicopathological and prognostic values of MTHFD2 in LUAD patients. We conducted a series of functional experiments in vivo and in vitro to explore novel mechanism of MTHFD2 in LUAD. The results showed that MTHFD2 was significantly up‐regulated in LUAD tissues and predicted poor prognosis of LUAD patients. Knockdown of MTHFD2 dramatically inhibited cell proliferation and migration by blocking the cell cycle and inducing the epithelial‐mesenchymal transition (EMT). In addition, MTHFD2 knockdown suppressed LUAD growth and metastasis in cell‐derived xenografts. Mechanically, we found that MTHFD2 promoted LUAD cell growth and metastasis via AKT/GSK‐3β/β‐catenin signalling. Finally, we identified miR‐30a‐3p as a novel regulator of MTHFD2 in LUAD. Collectively, MTHFD2 plays an oncogenic role in LUAD progression and is a promising target for LUAD diagnosis and therapy.     

Circulating miR‐19a‐3p and miR‐19b‐3p characterize the human aging process and their isomiRs associate with healthy status at extreme ages

Blood circulating microRNAs (c‐miRs) are potential biomarkers to trace aging and longevity trajectories to identify molecular targets for anti‐aging therapies. Based on a cross‐sectional study, a discovery phase was performed on 12 donors divided into four groups: young, old, healthy, and unhealthy centenarians. The identification of healthy and unhealthy phenotype was based on cognitive performance and capabilities to perform daily activities. Small RNA sequencing identified 79 differentially expressed c‐miRs when comparing young, old, healthy centenarians, and unhealthy centenarians. Two miRs, that is, miR‐19a‐3p and miR‐19b‐3p, were found increased at old age but decreased at extreme age, as confirmed by RT‐qPCR in 49 donors of validation phase. The significant decrease of those miR levels in healthy compared to unhealthy centenarians appears to be due to the presence of isomiRs, not detectable with RT‐qPCR, but only with a high‐resolution technique such as deep sequencing. Bioinformatically, three main common targets of miR‐19a/b‐3p were identified, that is, SMAD4, PTEN, and BCL2L11, converging into the FoxO signaling pathway, known to have a significant role in aging mechanisms. For the first time, this study shows the age‐related increase of plasma miR‐19a/b‐3p in old subjects but a decrease in centenarians. This decrease is more pronounced in healthy centenarians and was confirmed by the modified pattern of isomiRs comparing healthy and unhealthy centenarians. Thus, our study paves the way for functional studies using c‐miRs and isomiRs as additional parameter to track the onset of aging and age‐related diseases using new potential biomarkers.     

Androgen receptor suppresses vasculogenic mimicry in hepatocellular carcinoma via circRNA7/miRNA7‐5p/VE‐cadherin/Notch4 signalling

Androgen receptor (AR) can suppress hepatocellular carcinoma (HCC) invasion and metastasis at an advanced stage. Vasculogenic mimicry (VM), a new vascularization pattern by which tumour tissues nourish themselves, is correlated with tumour progression and metastasis. Here, we investigated the effect of AR on the formation of VM and its mechanism in HCC. The results suggested that AR could down‐regulate circular RNA (circRNA) 7, up‐regulate micro RNA (miRNA) 7‐5p, and suppress the formation of VM in HCC Small hairpin circR7 (ShcircR7) could reverse the impact on VM and expression of VE‐cadherin and Notch4 increased by small interfering AR (shAR) in HCC, while inhibition of miR‐7‐5p blocked the formation of VM and expression of VE‐cadherin and Notch4 decreased by AR overexpression (oeAR) in HCC. Mechanism dissection demonstrated that AR could directly target the circR7 host gene promoter to suppress circR7, and miR‐7‐5p might directly target the VE‐cadherin and Notch4 3′UTR to suppress their expression in HCC. In addition, knockdown of Notch4 and/or VE‐cadherin revealed that shVE‐cadherin or shNotch4 alone could partially reverse the formation of HCC VM, while shVE‐cadherin and shNotch4 together could completely suppress the formation of HCC VM. Those results indicate that AR could suppress the formation of HCC VM by down‐regulating circRNA7/miRNA7‐5p/VE‐Cadherin/Notch4 signals in HCC, which will help in the design of novel therapies against HCC.