Hepatocellular carcinoma-derived exosomal miRNA-761 regulates the tumor microenvironment by targeting the SOCS2/JAK2/STAT3 pathway.

BACKGROUND: Exosomes and exosomal microRNAs have been implicated in tumor occurrence and metastasis. Our previous study showed that microRNA-761 (miR-761) is overexpressed in hepatocellular carcinoma (HCC) tissues and that its inhibition affects mitochondrial function and inhibits HCC metastasis. The mechanism by which exosomal miR-761 modulates the tumor microenvironment has not been elucidated. METHODS: Exosomal miR-761 was detected in six cell lines. Cell counting kit-8 (CCK-8) and transwell migration assays were performed to determine the function of exosomal miR-761 in HCC cells. The luciferase reporter assay was used to analyze miR-761 target genes in normal fibroblasts (NFs). The inhibitors AZD1480 and C188-9 were employed to determine the role of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway in the transformation of cancer-associated fibroblasts (CAFs). RESULTS: In this study, we characterized the mechanism by which miR-761 reprogrammed the tumor microenvironment. We found that HCC-derived exosomal miR-761 was taken up by NFs. Moreover, HCC exosomes affected the tumor microenvironment by activating NFs via suppressor of cytokine signaling 2 (SOCS2) and the JAK2/STAT3 signaling pathway. CONCLUSIONS: These results demonstrated that exosomal miR-761 modulated the tumor microenvironment via SOCS2/JAK2/STAT3 pathway-dependent activation of CAFs. Our findings may inspire new strategies for HCC prevention and therapy.

Downregulation of miR-761 ameliorates radiation-induced pulmonary fibrosis by regulating PGC-1α.

Background: Radiation-induced pulmonary fibrosis (RIPF) is a serious complication in patients treated with transthoracic irradiation. To date, there are no effective drugs for RIPF treatment. In this study, we attempted to explore the function of miR-761 in RIPF, further investigate its potential mechanism and evaluate its effectiveness in the treatment of RIPF. Methods: qRT-PCR analysis was used to detect miR-761 and peroxisome proliferator-activated receptor gamma (PPARg) coactivator-1 (PGC-1α) expression. Western Blot (WB) assay was applied to verify the regulation of PGC-1α by miR-761 and the expression of fibrosis-related proteins. Gel contraction assay was performed to demonstrate the level of fibroblast activation in vitro. A mouse RIPF model was used to validate the anti-fibrotic effect of Antagomir761. Bioinformatics analysis and dual-luciferase reporter assays were utilized to confirm the regulation relationship between miR-761 and PGC-1α. Results: The results showed that miR-761 was significantly elevated in irradiated mice lungs and fibroblasts. Overexpression of miR-761 in vitro promoted fibroblast activation. Whereas inhibition of miR-761 attenuated the degree of RIPF and inhibited fibroblast activation. Mechanistically, PGC-1α was a direct and functional target of miR-761, overexpression of PGC-1α inhibited irradiation-induced fibroblast activation, and knockdown of PGC-1α caused miR-761 inhibitor loses its anti-activation ability in irradiated cells. Conclusion: Our findings demonstrated that miR-761 regulated RIPF by targeting PGC-1α. Inhibition of miR-761 restored PGC-1α expression and attenuated RIPF damage, and miR-761 was a potential target for preventing the development of RIPF.

Long noncoding RNA ADIRF antisense RNA 1 upregulates insulin receptor substrate 1 to decrease the aggressiveness of osteosarcoma by sponging microRNA-761.

An increasing number of studies have supported the critical regulatory actions of long noncoding RNAs (lncRNAs) in osteosarcoma (OS). However, the detailed roles of adipogenesis regulatory factor-antisense RNA 1 (ADIRF-AS1) in OS have not been comprehensively described. Hence, we first detected ADIRF-AS1 expression in OS and evaluated its clinical significance. Functional experiments were then performed to determine the modulatory role of ADIRF-AS1 in OS progression. ADIRF-AS1 was found to be overexpressed in OS, and the overall survival of patients with OS who had high ADIRF-AS1 levels was shorter than that of those with low levels. ADIRF-AS1 knockdown led to restricted proliferation, migration, and invasiveness of OS cells and increased apoptosis. Additionally, ADIRF-AS1 downregulation impeded tumor growth in vivo. Mechanistically, ADIRF-AS1 acted as a competitive endogenous RNA for microRNA-761 (miR-761) that siphoned miR-761 away from its target, namely insulin receptor substrate 1 (IRS1), leading to IRS1 overexpression. Rescue experiments showed that low levels of miR-761 or restoration of IRS1 could neutralize the effects of ADIRF-AS1 ablation in OS cells. In summary, ADIRF-AS1 exacerbates the oncogenicity of the OS cells by targeting the miR-761/IRS1 axis. Our findings may aid in the advancement of lncRNA-directed therapeutics for OS.

Effect of long non-coding RNA nuclear-enriched abundant transcript on hypoxia-reoxygenation rat astrocyte injury by targeting microRNA-761 / 解剖学报

Objective To investigate the effect of long non-coding RNA (IncRNA) nuclear-enriched abundant transcript 1 (NEATl) on hypoxia-reoxygenation (H/R) glial astrocyte injury, and to explore whether the mechanism was related to the regulation of micro RNA (miR)-761. Methods Rat cortical astrocytes were cultured to construct a H/R injury model. Astrocytes were divided into control group, model group, model+ small interfering RNA negative control (si-NC) group, model+ si-NEATl group, model+ miR-NC group, model + miR-761 group, model + si-NEATl + anti-miR-NC group, model+si-NEATl+anti-miR-761 group. Expression of NEATl and miR-761 were detected by Real-time PCR. The experiment was repeated 3 times. The content of malonaldefryde (MDA), and the activity of superoxide dismutase (SOD) and catalase (CAT) were detected by kits. Dual luciferase reporter experiment and Real-time PCR were used to analyze the targeting relationship between NEATl and miR-761. The experiment was repeated 3 times. Results Compared with the control group, the cell apoptosis rate and MDA content of the model group increased significantly, SOD and CAT activities decreased significantly, NEATl expression increased significantly, and miR-761 expression decreased significantly (P< 0. 05). Compared with the model+si-NC group, the apoptosis rate and MDA content of the model+si-NEATl group reduced significantly, and SOD and CAT activities increased significantly (P < 0 . 0 5) . Compared with the model + miR-NC group, the apoptosis rate and MDA content of the model + miR-761 group reduced significantly, and SOD and CAT activities increased significantly (P < 0 . 0 5) . MiR-761 was the target gene of N E A T l, and NEATl negatively regulated miR-761 expression. Compared with the model+si-NEATl+anti-miR-NC group, the apoptosis rate and MDA content of the model+siNEAT1+anti-miR-761 group increased significantly, and SOD and CAT activities decreased significantly (P < 0 . 0 5) . Conclusion Interference with NEATl expression can protect astrocytes from H / R injury by up-regulating miR-761.

Hepatocellular carcinoma-derived exosomal miRNA-761 regulates the tumor microenvironment by targeting the SOCS2/JAK2/STAT3 pathway / 世界急诊医学杂志（英文）

@#BACKGROUND: Exosomes and exosomal microRNAs have been implicated in tumor occurrence and metastasis. Our previous study showed that microRNA-761 (miR-761) is overexpressed in hepatocellular carcinoma (HCC) tissues and that its inhibition affects mitochondrial function and inhibits HCC metastasis. The mechanism by which exosomal miR-761 modulates the tumor microenvironment has not been elucidated. METHODS: Exosomal miR-761 was detected in six cell lines. Cell counting kit-8 (CCK-8) and transwell migration assays were performed to determine the function of exosomal miR-761 in HCC cells. The luciferase reporter assay was used to analyze miR-761 target genes in normal fibroblasts (NFs). The inhibitors AZD1480 and C188-9 were employed to determine the role of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway in the transformation of cancer-associated fibroblasts (CAFs). RESULTS: In this study, we characterized the mechanism by which miR-761 reprogrammed the tumor microenvironment. We found that HCC-derived exosomal miR-761 was taken up by NFs. Moreover, HCC exosomes affected the tumor microenvironment by activating NFs via suppressor of cytokine signaling 2 (SOCS2) and the JAK2/STAT3 signaling pathway. CONCLUSIONS: These results demonstrated that exosomal miR-761 modulated the tumor microenvironment via SOCS2/JAK2/STAT3 pathway-dependent activation of CAFs. Our findings may inspire new strategies for HCC prevention and therapy.

Knockdown of lncRNA PVT1 inhibits the proliferation and accelerates the apoptosis of colorectal cancer cells via the miR­761/MAPK1 axis.

Colorectal cancer (CRC) is associated with high morbidity rates. Long non­coding RNAs (lncRNAs) participate in the development of CRC. However, the potential roles of lncRNA plasmacytoma variant translocation 1 (PVT1) in CRC remain unknown. Therefore, the aim of the present study was to investigate the potential roles of PVT1 in CRC. Reverse transcription­quantitative PCR and western blot analyses were conducted to determine the mRNA and protein expression levels. The cellular behaviors were detected using 5­Ethynyl­2'­deoxyuridine, Cell Counting Kit­8 and flow cytometry assays. The interaction between PVT1 and microRNA (miR)­761 or MAPK1 was confirmed using a dual­luciferase reporter assay. Moreover, the Pearson's method was applied for correlation analysis. The results demonstrated that the expression levels of PVT1 and MAPK1 were upregulated, while miR­761 was downregulated in CRC tissues. The expression of PVT1 was positively correlated with MAPK1 and negatively correlated with miR­761. In addition, PVT1 sponged miR­761 to upregulate MAPK1 expression. It was found that the knockdown of PVT1 expression inhibited the proliferation and promoted the apoptosis of CRC cells, which was more potent in cells transfected with miR­761. The regulatory role of small interfering RNA­PVT1 on the expression of apoptosis­related genes was reduced by MAPK1. Collectively, the present results suggested that knockdown of PVT1 may inhibit the progression of CRC by regulating the miR­761/MAPK1 axis, which may provide a promising biomarker for the treatment of CRC.

[Effect of lncRNA HOTAIR on the radiosensitivity of HCCLM3 cells].

Objective: To investigate the effect of down-regulating long non-coding RNA (lncRNA) and HOX transcript antisense RNA (HOTAIR) targeting miR-761 on the radiosensitivity of HCCLM3. Methods: The expression of HOTAIR in liver cancer cells HuH-7, SNU-449, HCCLM3 and normal liver cells L-02 were measured by real-time quantitative PCR. HCCLM3 cells were divided into control, Sh-NC (transfected shRNA negative control), Sh-HOTAIR (transfected HOTAIR shRNA), RAD+Sh-NC (transfected shRNA negative control and irradiated with 8Gy dose), and RAD+Sh-HOTAIR (HOTAIR shRNA was transfected and irradiated with 8Gy dose) group. Apoptosis was detected by flow cytometry, Bcl-2 Associated X Protein (Bx-2), cleaved cysteine-containing Cleaved cysteinyl aspartate specific proteinase 3 (C-Caspase-3) protein expression. Sh-NC, Sh-HOTAIR cells were irradiated with 0, 2, 4, 6, 8 Gy, and plate-clone experiments were used to determine radiosensitivity. Bioinformatics software predicted that miR-761 might be a target gene of HOTAIR, and the luciferase reporter system identified the targeting relationship. The miR-761 inhibitor, HOTAIR shRNA and inhibitor negative control, and HOTAIR shRNA were co-transfected into HCCLM3 cells, respectively. Cell apoptosis and Bax and C-cysteine-containing aspartate proteins were also measured using the above method, as well as the hydrolase-3 protein expression and cell survival fraction. Results: The expression levels of HOTAIR in liver cancer cells HuH-7, SNU-449, and HCCLM3 were higher than those in normal liver cells L-02 (1.85±0.12, 2.27±0.23, 2.68±0.15 vs 1.00±0.09, P<0.05). Compared with Sh-NC, the apoptosis rate of Sh-HOTAIR, RAD+Sh-NC cells and Bax, C-Caspase-3 protein levels are higher [Apoptotic rate: (13.47±1.32)%, (12.84±1.19)% vs (2.98±0.27)%; Bax protein: 0.74±0.08, 0.72±0.06 vs 0.42±0.06; C-Caspase-3 protein: 0.56±0.06, 0.54±0.08 vs 0.25±0.04, all P<0.05]. Compared with Sh-HOTAIR and RAD+Sh-NC, RAD+Sh-HOTAIR cell apoptosis rate and Bax, C-Caspase-3 protein levels are higher [apoptosis rate:(22.57±2.36)% vs (13.47±1.32)%, (12.84±1.19)%, Bax protein: 0.99±0.11 vs 0.74±0.08, 0.72±0.06, C-Caspase-3 protein: 1.03±0.12 vs 0.56±0.06, 0.54±0.08,all P<0.05]. Compared with Sh-NC, Sh-HOTAIR cells had lower survival scores and higher radiosensitivity (P<0.05). HOTAIR targets negative regulation of miR-761 expression. Compared with cells co-transfected with inhibitor negative control and HOTAIR shRNA, cells co-transfected with miR-761 inhibitor and HOTAIR shRNA had lower apoptosis rate after radiation treatment [(10.24±1.32)% vs (21.84±2.01))%], Bax (0.50±0.06 vs 1.01±0.10) and C-Caspase-3 protein (0.56±0.07 vs 1.05±0.14) had lower expression and higher cell survival scores (all P<0.05). Conclusion: Down-regulating lncRNA HOTAIR targets miR-761 to increase the radiosensitivity of HCCLM3.

MicroRNA-761 suppresses remodeling of nasal mucosa and epithelial-mesenchymal transition in mice with chronic rhinosinusitis through LCN2.

BACKGROUND: Chronic rhinosinusitis (CRS) is characterized by persistent symptomatic inflammation of the nasal passage and sinus mucosa. Various microRNAs (miRs) have been implicated in CRS. Hence, the current study was conducted to explore the effect of microRNA-761 (miR-761) on remodeling of nasal mucosa and epithelial-mesenchymal transition (EMT). METHODS: Bioinformatics analysis was initially performed to predict the differentially expressed genes (DEGs) associated with CRS. Gene targeting relationship between miR-761 and lipocalin 2 (LCN2) was analyzed by bioinformatics analysis and verified using dual-luciferase reporter gene assay. Histopathological analyses of the nasal mucosa tissues were conducted via hematoxylin-eosin (HE) and alcian blue (AB)-periodic acid Schiff (PAS) staining. ELISA was employed to determine the IL-8 and MMP-9 levels. To define downstream pathway of miR-761, levels of proteins related to LCN2/Twist1 signaling pathway were assessed. Additionally, the effects of miR-761 on EMT, proliferation, and apoptosis were determined. RESULTS: LCN2 was highly expressed in CRS. LCN2 was a target of miR-761. miR-761 overexpression or LCN2 silencing decreased IL-8 and MMP-9 levels and morphological changes in nasal epithelial tissue from CRS mice. Overexpressed miR-761 or silenced LCN2 decreased the expression of LCN2 and Twist1, indicating LCN2/Twist1 signaling pathway was inactivated. Moreover, miR-761 overexpression or LCN2 silencing reduced the expression of N-cadherin and vimentin, while increased that of E-cadherin, suggesting inhibition of EMT. Furthermore, miR-761 overexpression or LCN2 silencing promoted cell proliferation and inhibited cell apoptosis in CRS. CONCLUSION: Taken together, miR-761 suppressed the remodeling of nasal mucosa through inhibition of LCN2 and the LCN2/Twist1 signaling pathway.

MicroRNA-761 targets FGFR1 to suppress the malignancy of osteosarcoma by deactivating PI3K/Akt pathway.

PURPOSE: MicroRNA-761 (miR-761) has been reported to be deregulated in many types of human cancers and play important roles in cancer genesis and progression. However, the biological roles of miR-761 in osteosarcoma (OS) and the underlying mechanisms remain largely unknown. METHODS: The expression of miR-761 in OS tissues and cell lines was analyzed using RT-qPCR. A series of gain-of-function tests were performed, and status of malignancy was evaluated on basis of proliferation, migration, invasion, and apoptosis using different assays to determine the regulatory roles of miR-761 in OS cells in vivo and in vitro. Notably, the mechanisms underlying the action of miR-761 in the pathogenesis of OS were investigated using bioinformatic analysis, luciferase reporter assay, RT-qPCR and Western blotting. RESULTS: The results showed that miR-761 expression was decreased in OS tissues and cell lines and is closely correlated with clinical stage and distant metastasis in OS patients. Patients with OS having low miR-761 expression showed worse prognosis compared to OS patients with high miR-761 expression. Restoring the miR-761 expression level decreased OS cell proliferation, migration, and invasion in vitro; promoted cell apoptosis in vitro; and impaired tumor growth in vivo. In addition, fibroblast growth factor receptor 1 (FGFR1) was found as a direct target gene of miR-761 in OS cells. Furthermore, silencing FGFR1 expression stimulated the tumor-suppressing roles of miR-761 upregulation in OS cells, whereas the activity of miR-761 overexpression in OS cells was abolished by the restoration of FGFR1 expression. Moreover, restoration of miR-761 expression deactivated the PI3K/Akt pathway in vitro and in vivo. CONCLUSION: These results suggest that miR-761 plays anti-cancer roles in OS by directly targeting FGFR1 and deactivating the PI3K/Akt pathway. The newly identified miR-761/FGFR1/PI3K/Akt pathway partially illustrates the mechanism of OS pathogenesis and presents a novel candidate therapeutic target for antitumor therapy.

MicroRNA-761 inhibits the metastasis of gastric cancer by negatively regulating Ras and Rab interactor 1.

Gastric cancer (GC), the second most common malignant cancer worldwide, gives rise to a number of cancer-associated fatalities annually. Accumulating evidence has shown that microRNAs (miRs) may serve as oncogenes or tumor suppressors in GC development. The aim of this study was to discover the expression, function and mechanism of miR-761 in GC progression. First, the findings revealed that the expression level of miR-761 was significantly decreased in GC cell lines and tissues. The functional studies showed that miR-761 in GC cells inhibited tumor proliferation and metastasis. In the mechanistic study, through an online database search and luciferase assay, Ras and Rab interactor 1 (RIN1), which has been demonstrated as an oncogene in various types of cancer, including GC, was identified as a target of miR-761. Notably, miR-761 expression was demonstrated to be negatively correlated with RIN1 mRNA levels in GC tissues. Simultaneously, overexpression of RIN1 partially rescued the inhibitory effect of miR-761 mimic in the GC cells. The present study provided new insights into the role of miR-761 in the progression of GC, and implicated the potential application of miR-761 in GC cell therapy.

microRNA-761 regulates glycogen synthase kinase 3ß expression and promotes the proliferation and cell cycle of human gastric cancer cells.

It has been well documented that aberrant expression of microRNAs (miRs) serves important roles in cancer progression. The present study investigated the roles of miR-761 on gastric cancer (GC) cell proliferation. Reverse transcription polymerase chain reaction indicated that miR-761 was frequently upregulated in GC tissues and cells. Overexpression of miR-761 promoted the cell proliferation, cell colony formation and cell cycle of GC cells. Bioinformatics analysis revealed that miR-761 might target the 3'-untranslated region of glycogen synthase kinase 3ß, and was confirmed by luciferase reporter assay and western blot analysis. Taken together, the results of the present study revealed miR-761 as a tumor promoter in GC, and that it could be considered as a novel therapeutic target for patients with GC.

MicroRNA-761 regulates mitochondrial biogenesis in mouse skeletal muscle in response to exercise.

MicroRNAs (miRNAs) have been suggested to play critical roles in skeletal muscle in response to exercise. Previous study has shown that miR-761 was involved in a novel model regulating the mitochondrial network. However, its role in mitochondrial biogenesis remains poorly understood. Therefore, the current study was aimed to examine the effect of miR-761 on mitochondrial biogenesis in skeletal muscle. Real-time quantitative PCR analysis demonstrated that aberrantly expressed miR-761 is involved in exercise activity and miR-761 is decreased by exercise training compared with the sedentary control mice. miR-761 suppresses mitochondrial biogenesis of C2C12 myocytes by targeting the 3'-UTR of peroxisome proliferator-activated receptor gamma (PPARγ) coactivator-1 (PGC-1α). Overexpression of miR-761 was capable of inhibiting the protein expression levels of PGC-1α. Moreover, miR-761 overexpression suppressed the p38 MAPK signaling pathway and down-regulated the expression of phosphorylated MAPK-activated protein kinase-2 (P-MK2), a downstream kinase of p38 MAPK. The phosphorylation of activating transcription factors 2 (ATF2) that plays a functional role in linking the activation of the p38 MAPK pathway to enhanced transcription of the PGC-1α was also inhibited by the overexpression of miR-761. These findings revealed a novel regulation mechanism for miR-761 in skeletal myocytes, and contributed to a better understanding of the modulation of skeletal muscle in response to exercise.