Forced expression of microRNA-221-3p exerts protective effects against manganese-induced cytotoxicity in human lung epithelial cells

Manganese (Mn)-induced pulmonary toxicity and the underlying molecular mechanisms remain largely enigmatic. Further, in recent years, microRNAs (miRNAs) have emerged as regulators of several pollutants-mediated toxicity. In this context, our study aimed at elucidating whether miRNAs are involved in manganese (II) chloride (MnCl2) (Mn2+)-induced cytotoxicity in lung epithelial cells. Growth inhibition of Mn2+ towards normal human bronchial epithelial (BEAS-2B) and adenocarcinomic human alveolar basal epithelial (A549) cells was analyzed by MTT assay following 24 or 48 h treatment. Reactive oxygen species (ROS) generation, mitochondrial membrane potential (ΔΨm), cell cycle arrest, and apoptosis were evaluated by flow cytometry. RT-qPCR and Western blot were performed to analyze the expression of cyclins, anti-oxidant genes, and miRNAs. We used small RNA sequencing to investigate Mn2+-induced changes in miRNA expression patterns. In both cell lines, Mn2+ treatment inhibited growth in a dose-dependent manner. Further, compared with vehicle-treated cells, Mn2+ (250 μM) treatment induced ROS generation, cell cycle arrest, apoptosis, and decreased ΔΨm as well as altered the expression of cyclins and anti-oxidant genes. Sequencing data revealed that totally 296 miRNAs were differentially expressed in Mn2+-treated cells. Among them, miR-221-3p was one of the topmost down-regulated miRNAs in Mn2+-treated cells. We further confirmed this association in A549 cells. In addition, transient transfection was performed to study gain-of-function experiments. Forced expression of miR-221-3p significantly improved cell viability and reduced Mn2+-induced cell cycle arrest and apoptosis in BEAS-2B cells. In conclusion, miR-221-3p may be the most likely target that accounts for the cytotoxicity of Mn2+-exposed lung epithelial cells.

Exosome-Derived MicroRNA-221-3p Desensitizes Breast Cancer Cells to Adriamycin by Regulating PIK3r1-Mediated Glycose Metabolism

Background: Cancer-derived exosomes facilitate chemoresistance by transferring RNAs, yet their role in exosomal microRNA-221-3p (miR-221-3p) regulation of Adriamycin resistance in breast cancer (BC) remains unclear. Methods: Adriamycin-resistant BC cells were developed from MCF-7 and MDA-MB-231 cells by incremental Adriamycin exposure. The miR-221-3p levels were quantified by quantitative reverse transcription-polymerase chain reaction. Subsequently, exosomes were isolated and incubated with BC cells, and exosome-mediated Adriamycin sensitivity was evaluated using Cell Counting Kit-8, colony formation, and flow cytometry assays. Sensitive cells were cocultured with miR-221-3p inhibitor-treated cells to assess Adriamycin resistance. Moreover, the interaction between miR-221-3p and phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) was validated using a dual luciferase reporter gene assay. Mimics and inhibitors were used to determine the effects of miR-221-3p on Adriamycin resistance. Results: Elevated levels of miR-221-3p expression were observed in Adriamycin-resistant BC cells and exosomes. Sensitive cells were cocultured with exosomes from resistant cells, resulting in increased half-maximal inhibitory concentration value and proliferation, and reduced Adriamycin-induced apoptosis. However, the effects of coculturing sensitive cells with Adriamycin-resistant cells were significantly weakened by miR-221-3p inhibitor transfection in Adriamycin-resistant cells. PIK3R1 was found to be a target of miR-221-3p, and miR-221-3p mimics enhanced Adriamycin resistance in sensitive cells. miR-221-3p inhibitors increased the expression of PIK3R1, p-AKT, c-Myc, HK2, and PKM2, decreased FOXO3 expression, and weakened the Adriamycin resistance in resistant cells. Conclusions: miR-221-3p can be transferred between BC cells through exosomes. High levels of miR-221-3p were found to target PIK3R1 and promoted Adriamycin resistance in BC cells. [Figure: see text].

GAS5, a long noncoding RNA, contributes to annulus fibroblast osteogenic differentiation and apoptosis in intervertebral disk degeneration via the miR-221-3p/SOX11 axis

miR-221-3p has been reported to attenuate the osteogenic differentiation of annulus fibrosus cells (AFs), which has been implicated in intervertebral disk degeneration (IVDD) development. This study aimed to elucidate miR-221-3p's role in osteogenic differentiation and apoptosis of AFs in an IVDD model. After successfully establishing an IVDD rat model by annulus fibrosus needle puncture, AFs were isolated. Bioinformatics, dual-luciferase reporter, and AGO2-RNA immunoprecipitation (RIP) assays predicted and confirmed the potential miR-221-3p lncRNA and gene target. Functional analyses were performed after AF transfection to explore the roles of the identified lncRNA and gene. Western blotting, Alkaline phosphatase (ALP), and Alizarin red and TUNEL staining were performed to investigate AF apoptosis and osteogenic differentiation with different transfections. Compared with AFs isolated from sham rats, IVDD-isolated Afs exhibited stronger osteogenic potential and higher apoptosis rates accompanied by miR-221-3p downregulation. The growth arrest-specific transcript 5 (GAS5) was identified as miR-221-3p's target lncRNA, which was highly expressed in IVDD. GAS5 overexpression facilitated AF apoptosis and osteogenic differentiation, whereas silencing GAS5 had the opposite effect. SRY box-related11 (SOX11) was identified as a downstream miR-221-3p target gene in IVDD. GASS silencing-induced suppression of AF apoptosis and osteogenic differentiation could be reversed by SOX11 overexpression. Our findings uncovered a lncRNA GAS5/miR-221-3p/SOX11 axis in Afs under IVDD, which may help implement novel IVDD therapeutic strategies.

Clinical significance and immune characteristics analysis of miR-221-3p and its key target genes related to epithelial-mesenchymal transition in breast cancer

BACKGROUND

MicroRNA-221-3p (miR-221-3p) facilitates the advancement of breast cancer (BC) through the induction of epithelial-mesenchymal transition (EMT). Our research aimed to utilize bioinformatics to discover possible EMT-related target genes (ETGs) of miR-221-3p and examine their roles in breast cancer.

METHODS

We employed bioinformatics techniques to identify ten key ETGs of miR-221-3p. Subsequently, we conducted an extensive analysis of both miR-221-3p and the ten ETGs, including clinical significance and immune characteristics.

RESULTS

The expression of miR-221-3p was notably higher in Basal-like BC compared to other subtypes and adjacent normal tissue. Our pathway analysis suggested that miR-221-3p might regulate EMT through the MAPK signaling pathway by targeting its ETGs. Among the ETGs, seven core genes (EGFR, IGF1, KDR, FGF2, KIT, FGFR1, and FGF1) exhibited downregulation in BC. Conversely, ERBB2, SDC1, and MMP14 showed upregulation in BC and displayed potential diagnostic value. The analysis of prognostication indicated that increased levels of SDC1 and MMP14 were correlated with an unfavorable prognosis, whereas elevated expression of KIT was associated with a more favorable prognosis. The infiltration of various immune cells and the expression of immune checkpoint genes (ICGs) exhibited positive correlations with most ETGs and miR-221-3p. SDC1 exhibited a greater tumor mutational burden (TMB) score, while ERBB2, KDR, FGF2, KIT, FGFR1, and FGF1 showed lower TMB scores. Furthermore, decreased ERBB2 and KDR expression levels were correlated with elevated microsatellite instability (MSI) scores. Elevated expression of ETGs was linked to decreased mRNA stemness indices (mRNAsi), whereas miR-221-3p displayed the opposite pattern. Most ETGs and miR-221-3p expression exhibited a negative correlation with IC50 values for drugs. Among the ETGs, amplification was the most significant genetic alteration, except for IGF1.

CONCLUSION

In conclusion, miR-221-3p acts as a unique indicator for Basal-like BC. The examination revealed ten essential ETGs of miR-221-3p, some of which show potential as diagnostic and prognostic markers. The in-depth examination of these ten ETGs and miR-221-3p indicates their participation in the development of BC, emphasizing their promise as innovative targets for therapy in BC patients.

Correlation of mir-221-3p differential expression with clinical characteristics of gastric cancer patients

BACKGROUND

Gastric cancer (GC) is one of the most common digestive malignancies. Although miR-221-3p was defined as a novel biomarker in many types of cancer, the relationship between its expression differences and the clinicopathological characteristics and prognosis of GC patients was yet to be fully understood.

METHODS AND RESULTS

TCGA database was utilized to predict the potential biological function of miR-221-3p in GC. QRT-PCR and RNA FISH were performed to detect the expression levels of miR-221-3p in GC. The miR-221-3p expression levels in GC tissues and cells were significantly higher than those in paracancerous tissues (p < 0.001) and normal gastric mucosal cells (p < 0.05). Higher expression levels of miR-221-3p were associated with tumor diameter ≥ 4 cm (χ2 = 5.519, p = 0.019), cTNM stage (III + IV) (χ2 = 28.013, p = 0.000), lymph node metastasis (χ2 = 23.272, p = 0.000) and distant metastasis (χ2 = 7.930, p = 0.005). Kaplan-Meier survival analysis showed a better prognosis for GC patients with miR-221-3p low expression(HR = 4.520, 95% CI: 1.844-11.075).

CONCLUSIONS

miR-221-3p is highly expressed in GC tissues, which plays an important role in tumorigenesis, invasion and metastasis. miR-221-3p may become an important biomarker and potential molecular therapeutic target for patients with GC.

Relevance and mechanism of STAT3/miR-221-3p/Fascin-1 axis in EGFR TKI resistance of triple-negative breast cancer

The epidermal growth factor receptor 1 (EGFR) plays a crucial role in the progression of various malignant tumors and is considered a potential target for treating triple-negative breast cancer (TNBC). However, the effectiveness of representative tyrosine kinase inhibitors (TKIs) used in EGFR-targeted therapy is limited in TNBC patients. In our study, we observed that the TNBC cell lines MDA-MB-231 and MDA-MB-468 exhibited resistance to Gefitinib. Treatment with Gefitinib caused an upregulation of Fascin-1 (FSCN1) protein expression and a downregulation of miR-221-3p in these cell lines. However, sensitivity to Gefitinib was significantly improved in both cell lines with either inhibition of FSCN1 expression or overexpression of miR-221-3p. Our luciferase reporter assay confirmed that FSCN1 is a target of miR-221-3p. Moreover, Gefitinib treatment resulted in an upregulation of phosphorylated signal transducer and activator of transcription 3 (p-STAT3) in MDA-MB-231 cells. Using Stattic, a small-molecule inhibitor of STAT3, we observed a significant enhancement in the inhibitory effect of Gefitinib on the growth, migration, and invasion of MDA-MB-231 cells. Additionally, Stattic treatment upregulated miR-221-3p expression and downregulated FSCN1 mRNA and protein expression. A strong positive correlation was noted between the expression of STAT3 and FSCN1 in breast cancer tissues. Furthermore, patients with high expression levels of both STAT3 and FSCN1 had a worse prognosis. Our findings suggest that elevated FSCN1 expression is linked to primary resistance to EGFR TKIs in TNBC. Moreover, we propose that STAT3 regulates the expression of miR-221-3p/FSCN1 and therefore modulates resistance to EGFR TKI therapy in TNBC. Combining EGFR TKI therapy with inhibition of FSCN1 or STAT3 may offer a promising new therapeutic option for TNBC.

MiR-221-3p/222-3p Cluster Expression in Human Adipose Tissue Is Related to Obesity and Type 2 Diabetes

The progression of obesity and type 2 diabetes (T2D) is intricately linked with adipose tissue (AT) angiogenesis. Despite an established network of microRNAs (miRNAs) regulating AT function, the specific role of angiogenic miRNAs remains less understood. The miR-221/222 cluster has recently emerged as being associated with antiangiogenic activity. However, no studies have explored its role in human AT amidst the concurrent development of obesity and T2D. Therefore, this study aims to investigate the association between the miR-221-3p/222-3p cluster in human AT and its regulatory network with obesity and T2D. MiR-221-3p/222-3p and their target gene (TG) expression levels were quantified through qPCR in visceral (VAT) and subcutaneous (SAT) AT from patients (n = 33) categorized based on BMI as normoweight (NW) and obese (OB) and by glycemic status as normoglycemic (NG) and type 2 diabetic (T2D) subjects. In silico analyses of miR-221-3p/222-3p and their TGs were conducted to identify pertinent signaling pathways. The results of a multivariate analysis, considering the simultaneous expression of miR-221-3p and miR-222-3p as dependent variables, revealed statistically significant distinctions when accounting for variables such as tissue depot, obesity, sex, and T2D as independent factors. Furthermore, both miRNAs and their TGs exhibited differential expression patterns based on obesity severity, glycemic status, sex, and type of AT depot. Our in silico analysis indicated that miR-221-3p/222-3p cluster TGs predominantly participate in angiogenesis, WNT signaling, and apoptosis pathways. In conclusion, these findings underscore a promising avenue for future research, emphasizing the miR-221-3p/222-3p cluster and its associated regulatory networks as potential targets for addressing obesity and related metabolic disorders.

miR-221-3p targets Ang-2 to inhibit the transformation of HCMECs to tip cells

Postembryonic angiogenesis is mainly induced by various proangiogenic factors derived from the original vascular network. Previous studies have shown that the role of Ang-2 in angiogenesis is controversial. Tip cells play a vanguard role in angiogenesis and exhibit a transdifferentiated phenotype under the action of angiogenic factors. However, whether Ang-2 promotes the transformation of endothelial cells to tip cells remains unknown. Our study found that miR-221-3p was highly expressed in HCMECs cultured for 4 h under hypoxic conditions (1% O2 ). Moreover, miR-221-3p overexpression inhibited HCMECs proliferation and tube formation, which may play an important role in hypoxia-induced angiogenesis. By target gene prediction, we further demonstrated that Ang-2 was a downstream target of miR-221-3p and miR-221-3p overexpression inhibited Ang-2 expression in HCMECs under hypoxic conditions. Subsequently, qRT-PCR and western blotting methods were performed to analyse the role of miR-221-3p and Ang-2 on the regulation of tip cell marker genes. MiR-221-3p overexpression inhibited CD34, IGF1R, IGF-2 and VEGFR2 proteins expression while Ang-2 overexpression induced CD34, IGF1R, IGF-2 and VEGFR2 expression in HCMECs under hypoxic conditions. In addition, we further confirmed that Ang-2 played a dominant role in miR-221-3p inhibitors promoting the transformation of HCMECs to tip cells by using Ang-2 shRNA to interfere with miR-221-3p inhibitor-treated HCMECs under hypoxic conditions. Finally, we found that miR-221-3p expression was significantly elevated in both serum and myocardial tissue of AMI rats. Hence, our data showed that miR-221-3p may inhibit angiogenesis after acute myocardial infarction by targeting Ang-2 to inhibit the transformation of HCMECs to tip cells.

Mammary Epithelial Cell-Derived Exosomal miR-221-3p Regulates Macrophage Polarization by Targeting Igf2bp2 during Mastitis

Mastitis affects the milk quality and yield and is the most expensive disease in dairy cows. Elucidation of the pathogenesis of mastitis is of great importance for disease control. As a medium of intercellular communication, exosomes play key roles in various inflammatory diseases by regulating macrophage polarization. However, the molecular factors in exosomes that mediate the intercellular communication between mammary epithelial cells and macrophages during mastitis remain to be further explored. In this study, we isolated and identified mammary epithelial cell-derived exosomes from a lipopolysaccharide (LPS)/lipoteichoic acid (LTA)-induced mastitis cell model, and we demonstrated that exosomes from LPS/LTA-stimulated mammary epithelial cells promote M1-type macrophage polarization in vivo and in vitro. Based on the results of high-throughput sequencing, we constructed a differential miRNA (microRNA) expression profile of exosomes and demonstrated that miR-221-3p was highly expressed. Furthermore, in vivo and in vitro experiments, combined with coculture experiments and fluorescence tracing, showed that high miR-221-3p expression promoted M1-type macrophage polarization, demonstrating the transcellular role of miR-221-3p. Mechanistically, dual luciferase reporter gene assays and rescue assays showed that miR-221-3p regulated macrophage polarization by targeting Igf2bp2. The results of this study will deepen our understanding of the pathogenesis of mastitis, and the molecular regulatory axis that was established in this study is expected to be a target for mastitis treatment.

Hypoxic papillary thyroid carcinoma cells-secreted exosomes deliver miR-221-3p to normoxic tumor cells to elicit a pro-tumoral effect by regulating the ZFAND5

Papillary thyroid cancer (PTC) has seen a worldwide expansion in incidence in the past three decades. Tumor-derived exosomes have been associated with the metastasis of cancer cells and are present within the local hypoxic tumor microenvironment, where they mediate intercellular communication by transferring molecules including microRNAs (miRNAs) between cells. Although miRNAs have been shown to serve as non-invasive biomarkers for cancer diagnosis, the role of hypoxia-induced tumor-derived exosomes in PTC progression remains unclear. Herein, we investigated the differentially expressed miRNA expression profiles from GEO datasets (GSE191117 and GSE151180) by using the DESeq package in R and identified a novel role for miR-221-3p as an oncogene in PTC development. In vivo and in vitro loss and gain assays were used to clarify the mechanism of hypoxic PTC cells derived exosomal-miR-221-3p in PTC. miR-221-3p was upregulated in human PTC plasma exosomes, tissues and cell lines. We found that hypoxic PTC cells derived exosomal-miR-221-3p promoted normoxic PTC cells proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) in vitro, while inhibition of miR-221-3p limited PTC tumor growth in our PTC xenograft model in nude mice. We finally identified ZFAND5, to be a miR-221-3p target. Mechanistically, hypoxic PTC cell lines-derived exosomes carrying miR-221-3p promoted PTC tumorigenesis by regulating ZFAND5. Our findings further the understanding of the underlying mechanisms associated with PTC progression and identify exosomal-miR-221-3p as a potential biomarker for the diagnosis and prognosis of PTC patients. Our study also suggests that miR-221-3p inhibitors could be a potential treatment strategy for PTC.

Exosomes from tannic acid-stimulated macrophages accelerate wound healing through miR-221-3p mediated fibroblasts migration by targeting CDKN1b

Tannic acid (TA) and its extraction were traditionally used for treatment of traumatic bleeding in China, and in the previous study we have demonstrated that TA could accelerate cutaneous wound healing in rats. We attempted to decipher the mechanism of TA in promoting wound healing. In this study, we found that TA could enhance the growth of macrophages and inhibit the release of inflammatory cytokines (IL-1β, IL-6, TNF-α, IL-8 and IL-10) through inhibition of NF-κB/JNK pathway. TA activated Erk1/2 pathway, leading to increased expressions of growth factors, bFGF and HGF. Scratch study revealed that TA did not directly regulate the migration function of fibroblasts, but could indirectly enhance fibroblasts migration by the supernatant of TA-treated macrophages. Transwell study further proved that TA stimulates macrophages to secrete exosomes enriched in miR-221-3p by activating the p53 signaling pathway, and the exosomes entered into the fibroblast cytoplasm and bound to 3'UTR of target gene CDKN1b which induced decreased expression level of CDKN1b, leading to promoting fibroblast migration. This study provided new insights into how TA accelerates wound healing in the inflammatory and proliferative phases of wound healing.

TP63 Functions as a Tumor Suppressor Regulated by GAS5/miR-221-3p Signaling Axis in Human Non-Small Cell Lung Cancer Cells

Background

Tumor protein p63 (TP63) has been proven to play a role as a tumor suppressor in some human cancers, including non-small cell lung cancer (NSCLC). This study aimed to investigate the mechanism of TP63 and analyze the underlying pathway dysregulating TP63 in NSCLC.

Methods

RT-qPCR and Western blotting assays were used to determine gene expression in NSCLC cells. The luciferase reporter assay was performed to explore the transcriptional regulation. Flow cytometry was used to analyze the cell cycle and cell apoptosis. Transwell and CCK-8 assays were performed to test cell invasion and cell proliferation, respectively.

Results

GAS5 interacted with miR-221-3p, and its expression was significantly reduced in NSCLC. GAS5, as a molecular sponge, upregulated the mRNA and protein levels of TP63 by inhibiting miR-221-3p in NSCLC cells. The upregulation of GAS5 inhibited cell proliferation, apoptosis, and invasion, which was partially reversed by the knockdown of TP63. Interestingly, we found that GAS5-induced TP63 upregulation promoted tumor chemotherapeutic sensitivity to cisplatin therapy in vivo and in vitro.

Conclusion

Our results revealed the mechanism by which GAS5 interacts with miR-221-3p to regulate TP63, and targeting GAS5/miR-221-3p/TP63 may be a potential therapeutic strategy for NSCLC cells.

Long non-coding RNA X-inactive specific transcript suppresses the progression of hepatocellular carcinoma through microRNA-221-3p-targeted regulation of O6-methylguanine-DNA methyltransferase

MicroRNA-221-3p (miR-221-3p) is an important regulator involved in the progression and prognosis of various cancers. In this study, we aimed to investigate the diagnostic and prognostic value of miR-221-3p expression along with long non-coding RNA X–inactive specific transcript (XIST), which was identified as its upstream regulator in hepatocellular carcinoma (HCC) by bioinformatics analysis, and further validated by RNA immunoprecipitation (RIP) and dual-luciferase reporter assays. Their expression was measured in tumor tissues and corresponding non-tumor tissues by quantitative real-time PCR (qRT-PCR), which revealed that XIST was weakly expressed in HCC cells and tumors, while miR-221-3p was overexpressed. Complete knockdown of XIST enhanced HCC cell proliferation and migration and inhibited apoptosis, as observed by MTT, transwell, and flow cytometry experiments, respectively. Animal studies validated that XIST knockdown induces tumor growth in vivo. In contrast, upregulation of XIST in HCC cells suppressed their proliferation and migration, stimulated apoptosis, and retarded the growth rate of tumors in vivo. These effects were partially reversed by upregulating miR-221-3p expression. Furthermore, we demonstrated that O⁶-methylguanine-DNA methyltransferase (MGMT) is a downstream target of miR-221-3p. It was weakly expressed in HCC cells and tumors and showed a negative correlation with miR-221-3p. Forced MGMT expression repressed proliferation and migration and enhanced apoptosis in HCC cells. Nevertheless, these anti-tumor effects induced by MGMT overexpression could be abolished by miR-221-3p upregulation. Collectively, our findings reveal that XIST blocks the development of HCC through miR-221-3p-targeted regulation of MGMT. This reveals a new mechanism involved in the development of HCC.

MiR-221-3p targets HIPK2 to promote diabetic wound healing

Diabetic foot ulcer is a severe complication of diabetes and is prone to being a chronic non-healing wound. We previously demonstrated that endothelial progenitor cell-derived exosomes, which contain miR-221-3p, alleviate diabetic ulcers. Here, to explore the mechanisms underlying this wound healing, we investigated the potential angiogenic effects of miR-221-3p in vitro using cultured human umbilical vein endothelial cells (HUVECs) and in vivo using a streptozotocin-induced mouse model of diabetes. We found that miR-221-3p promoted HUVEC viability, migration, and capillary-like tube formation. HUVECs cultured in high glucose showed up-regulated expression of homeodomain-interacting protein kinase 2 (HIPK2), a predicted target of miR-221-3p that may decrease angiogenesis. Knockdown of HIPK2 enhanced high glucose-suppressed HUVEC viability, migration, and tube formation, counteracting the effects of high glucose. Using a dual luciferase reporter assay, we found that HIPK2 was indeed a direct target of miR-221-3p. Subcutaneous injection of miR-221-3p agomir into diabetic mice promoted wound healing and suppressed HIPK2 expression in wound margin tissue. These findings indicate that HIPK2, as a direct target of miR-221-3p, contributes to the regulatory role of miR-221-3p in diabetic wound healing and may be a novel therapeutic target for diabetic foot ulcer.

Circ_0003159 upregulates LIFR expression through competitively binding to miR-221-3p/miR-222-3p to block gastric cancer development

Gastric cancer (GC) remains a major cause of cancer-related deaths. Increasing studies suggest that cancer development is accompanied by the deregulation of circular RNAs. We investigated the function of circ_0003159 in GC. The expression levels of circ_0003159, miR-221-3p/miR-222-3p and leukemia inhibitory factor receptor (LIFR) mRNA were measured by real-time quantitative polymerase chain reaction. Cell colony formation ability was assessed by colony formation assay, and cell viability was assessed by cell counting kit-8 assay. Cell apoptosis was assessed by flow cytometry assay and caspase3 activity. Cell migration and invasion were assessed by transwell assay. Glycolysis energy metabolism was assessed by 5'-triphosphate production, glucose uptake and lactate production. The protein levels of related marker proteins and LIFR were detected by western blot. The relationship between circ_0003159 and miR-221-3p/miR-222-3p, or LIFR and miR-221-3p/miR-222-3p was obtained from bioinformatics tools and verified by dual-luciferase reporter assay. A cancer tumorogenicity xenograft experiment in nude mice was conducted to determine the role of circ_0003159 in tumor growth by AGS cells. Our results showed that circ_0003159 expression was decreased in GC tissues and cells. Circ_0003159 overexpression sequestered GC cell viability, migration, invasion and glycolysis and induced cell apoptosis. MiR-221-3p and miR-222-3p were targets of circ_0003159, and the inhibition of miR-221-3p and miR-222-3p also blocked GC cell viability, migration, invasion and glycolysis and promoted cell apoptosis. LIFR was a common target of miR-221-3p and miR-222-3p. Interestingly, LIFR knockdown reversed the effects of circ_0003159 overexpression on GC cell behaviors. Circ_0003159 increased the expression level of LIFR by targeting miR-221-3p and miR-222-3p. The tumorigenicity assay showed that circ_0003159 overexpression inhibited tumor growth in vivo. In conclusion, circ_0003159 inhibited GC development in vitro and in vivo by enriching the level of LIFR via direct binding to miR-221-3p/miR-222-3p.

miR-221-3p regulates hepatocellular carcinoma cell proliferation, migration and invasion via targeting LIFR

INTRODUCTION AND OBJECTIVES

Hepatocellular carcinoma (HCC) is one of the most common and fatal cancers in the world. This study aims to investigate the mechanism by which miR-221-3p regulates HCC cell proliferation, migration and invasion, so as to provide a new idea for targeted therapy towards HCC.

MATERIALS AND METHODS

Expression quantification data including mature miRNA and mRNA were accessed from TCGA-LIHC dataset, and matched clinical information was obtained as well, which helped identify the miRNA of interest. Thereafter, effect of the miRNA on HCC cell biological functions was assessed with a series of in vitro experiments, such as qRT-PCR, MTT, wound healing assay and Transwell. To gain more insight into the mechanism of the miRNA in HCC, bioinformatics method was conducted to predict downstream target gene. The potential targeting relationship between the miRNA and the predicted mRNA was validated by dual-luciferase reporter assay. Western blot was performed to test protein expression.

RESULTS

MiR-221-3p identified by differential expression analysis was found to be significantly elevated in HCC tissue. Overexpressing miR-221-3p noticeably enhanced HCC cell proliferative, migratory and invasive abilities. Leukemia inhibitory factor receptor (LIFR), confirmed as a downstream target of miR-221-3p in HCC by dual-luciferase reporter assay, was poorly expressed in HCC tissue and cells. Additionally, the expression of LIFR was decreased following the targeted binding between miR-221-3p and LIFR 3'-UTR, while increasing the expression of LIFR attenuated the promoting effect of miR-221-3p on HCC cells.

CONCLUSION

MiR-221-3p is an oncogene in HCC cells, and it exerts its role in HCC cell viability and motility via targeting LIFR.

Long non-coding RNA myocardial infarction-associated transcript promotes 1-Methyl-4-phenylpyridinium ion-induced neuronal inflammation and oxidative stress in Parkinson's disease through regulating microRNA-221-3p/ transforming growth factor /nuclear factor E2-related factor 2 axis

This study attempted to evaluate the role of long non-coding RNA myocardial infarction-associated transcript (LncRNA MIAT) in Parkinson’s disease (PD). The mouse model was established through intraperitoneal injection with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and in vitro model was induced by administrating cell with 1-Methyl-4-phenylpyridinium ion (MPP⁺). Rotarod test was conducted to evaluate the motor coordination of PD mice. In order to investigate the roles of LncRNA MIAT in neuronal inflammation and oxidative stress, MIAT shRNA (shMIAT) was transfected into MPP⁺-treated cells, and cell viability, cell apoptosis and oxidative stress response were evaluated. To evaluate the interactions between LncRNA MIAT and microRNA-221-3p (miR-221-3p)/TGF-β1/Nrf2, miR-221-3p mimic, miR-221-3p inhibitor, NC-inhibitor and transforming growth factor-β1 shRNA (shTGF-β1) were subsequently transfected into MPP+-treated cells. Dual-luciferase reporter gene assays were performed to determine the interaction of miR-221-3p with MIAT or TGFB receptor 1 (TGFBR1). The expressions of LncRNA MIAT, miR-221-3p, TGFBR1, transforming growth factor (TGF-β1) and nuclear factor E2-related factor 2 (Nrf2) were measured by quantitative reverse-transcription polymerase chain reaction (RT-qPCR) and immunoblotting. As a result, LncRNA MIAT was abundantly expressed in PD mice and cells, while downregulation of LncRNA MIAT promoted the survival of neurons, inhibited apoptosis and oxidative stress in neurons. LncRNA MIAT bound to miR-221-3p, and there was a negative correlation between miR-221-3p and LncRNA MIAT expression. In addition, miR-221-3p targeted TGFBR1 and suppressed TGF-β1 expression but increased Nrf2 expression. LncRNA MIAT promoted MPP⁺-induced neuronal injury in PD via regulating TGF-β1/Nrf2 axis through binding with miR-221-3p.

miRNA-221-3p derived from M2-polarized tumor-associated macrophage exosomes aggravates the growth and metastasis of osteosarcoma through SOCS3/JAK2/STAT3 axis

Background: Enhanced infiltration of M2-polarized tumor-associated macrophages (TAMs) is linked to osteosarcoma (OS) metastasis and growth. Here, we aim to explore a novel miR-221-3p shuttled by M2-TAM exosomes in the growth and metastasis of OS cells.

Methods: THP-1 monocytes-derived M2-TAMs were induced by PMA/interleukin (IL)-4/IL-13 and then co-cultured with OS 143B and Saos2 cells. Overexpression or downregulation models of miR-221-3p were conducted to probe the impacts of exosome-derived M2-TAMs in OS cells. OS cell proliferative ability, colony formation, invasion, migration and apoptotic level were measured by the cell counting kit-8 (CCK-8) assay, colony formation, Transwell assay, and flow cytometry. Moreover, the SOCS3/JAK2/STAT3 axis in OS cells was testified by western blot, and a dual-luciferase reporter assay was conducted to confirm the link between miR-221-3p and SOCS3.

Results: OS cells enhanced M2 polarization of TAMs, which significantly promoted OS cells’ viability, colony formation, migration, invasion, and reduced apoptosis. Moreover, the exosomes enriched by miR-221-3p from M2-polarized TAMs (M2-TAMs) also aggravated the malignant behaviors of OS cells. However, down-regulation of miR-221-3p brought about contrary results. Further, in-vivo tests uncovered that overexpressing miR-221-3p enhanced OS cells’ growth. Mechanistically, SOCS3 was a downstream target of miR-221-3p, and up-regulation of miR-221-3p choked SOCS3 and activated JAK2/STAT3. However, the pharmacological intervention of the JAK2/STAT3 pathway obviously inhibited the malignant behaviors of OS cells, which were significantly reversed by miR-221-3p up-regulation.

Conclusion: The exosomal miR-221-3p derived from M2-TAMs aggravates OS progression via modulating the SOCS3/JAK2/STAT3 axis.

Identification of miRNA signatures and their therapeutic potentials in prostate cancer

BACKGROUND

Herein, we identified miRNA signatures that were able to differentiate malignant prostate cancer from benign prostate hyperplasia and revealed the therapeutic potential of these miRNAs against prostate cancer development.

METHODS AND RESULTS

MicroRNA expressions were determined by qPCR. MTT was used for cell viability analysis and immunohistochemistry was performed for Bax/Bcl-2 staining. ELISA was used to measure MMP2/9 levels. Wound healing assay was used for the evaluation of cell migration. Notably, expression levels of miR-125b-5p, miR-145-5p and miR-221-3p were significantly reduced in prostate cancer patients as compared to BPH patients. Moreover, ectopic expression of miR-125b-5p, miR-145-5p and miR-221-3p resulted in significant inhibition of cell proliferation and altered cell morphology. Also, expression level of Bax protein was increased while Bcl-2 level was reduced in cells treated with miR-125b-5p, miR-145-5p and miR-221-3p mimics. Enhanced expression of miR-125b-5p, miR-145-5p and miR-221-3p was also significantly altered the expression of caspase 3 and 8 levels. In addition, MMP9 levels were significantly reduced in cells ectopically expressing miR-221-3p. All miRNA mimics significantly interfered with the migration of prostate cancer cells.

CONCLUSIONS

Consequently, our findings point to an important role of these three miRNAs in prostate cancer and indicate that miR-125b-5p, miR-145-5p and miR-221-3p are potential therapeutic targets against prostate cancer.

LncRNA NEAT1_1 suppresses tumor-like biologic behaviors of fibroblast-like synoviocytes by targeting the miR-221-3p/uPAR axis in rheumatoid arthritis

Fibroblast-like synoviocytes (FLSs) are the predominant effector cells in the pathological progression of rheumatoid arthritis (RA). Therefore, elucidating the underlying molecular mechanism of the biologic behaviors in RA-FLSs will be helpful in developing the potent targets for the treatment of RA. We have previously documented that the tumor-like biologic behaviors of RA-FLSs are exacerbated by urokinase-type plasminogen activator receptor (uPAR), a specifically up-regulated receptor in RA-FLSs. Here, we investigate the further mechanism of uPAR and clarify its function in RA-FLSs. We demonstrate that miR-221-3p positively correlates to uPAR and regulates uPAR level in RA-FLSs. Simultaneously, one long noncoding RNA, nuclear paraspeckle assembly transcript 1_1 (NEAT1_1) is identified, which can predictively target miR-221-3p at three sites, indicating a strong possibility of being a competing endogenous RNA in RA-FLSs. Interestingly, NEAT1_1 and miR-221-3p can colocate in the nucleus and cytoplasm in RA-FLSs. Importantly, NEAT1_1 can act as a rheostat for the miR-221-3p/uPAR axis and the downstream JAK signaling. In line with the biologic function, NEAT1_1 negatively regulates the tumor-like characters, and cytokine secretions of RA-FLSs. Collectively, our data provide new insight into the mechanisms of NEAT1_1 in modulating RA-FLSs tumor-like behaviors. The targeting of NEAT1_1 and miR-221-3p/uPAR axis may have a promising therapeutic role in patients with RA.

MicroRNAs Targeting HIF-2α, VEGFR1 and/or VEGFR2 as Potential Predictive Biomarkers for VEGFR Tyrosine Kinase and HIF-2α Inhibitors in Metastatic Clear-Cell Renal Cell Carcinoma

Metastatic clear-cell renal cell carcinoma (m-ccRCC) is characterized by increased hypoxia-induced factor (HIF)-2α and vascular endothelial growth factor receptor (VEGFR)-dependent angiogenesis through loss of function of the von Hippel-Lindau protein. VEGFR tyrosine kinase inhibitors (VEGFR-TKIs) are a cornerstone of m-ccRCC treatment, and new treatments targeting HIF-2α are currently under investigation. However, predictive biomarkers for these treatments are lacking. In this retrospective cohort study including 109 patients treated with VEGFR-targeted therapies as first-line treatment, we aimed to study the possible predictive function of microRNAs (miRNAs) targeting HIF-2α, VEGFR1 and VEGFR2. We selected miRNAs inversely correlated with HIF-2α, VEGFR1 and/or VEGFR2 expression and with predicted target sites in the respective genes and subsequently studied their impact on therapeutic outcomes. We identified four miRNAs (miR-34c-5p, miR-221-3p, miR-222-3p and miR-3529-3p) inversely correlated with VEGFR1 and/or VEGFR2 expression and associated with tumor shrinkage and progression-free survival (PFS) upon treatment with VEGFR-TKIs, highlighting the potential predictive value of these miRNAs. Moreover, we identified three miRNAs (miR-185-5p, miR-223-3p and miR-3529-3p) inversely correlated with HIF-2α expression and associated with tumor shrinkage and PFS upon treatment with VEGFR-TKIs. These three miRNAs can have a predictive value not only upon treatment with VEGFR-TKIs but possibly also upon treatment with the upcoming HIF-2α inhibitor belzutifan.

Long Noncoding RNA GAS5 Targeting miR-221-3p/Cyclin-Dependent Kinase Inhibitor 2B Axis Regulates Follicular Thyroid Carcinoma Cell Cycle and Proliferation

INTRODUCTION

Follicular thyroid carcinoma (FTC) is more aggressive than the most common papillary thyroid carcinoma (PTC). However, the current research on FTC is less than PTC. Here, we investigated the effects of long noncoding RNA (lncRNA) GAS5 and miR-221-3p in FTC.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to detect GAS5 and miR-221-3p expression in the FTC tissues and cells. Cell proliferation was assessed by CCK8 and EdU assays. Flow cytometry was performed to determine the cell cycle. The dual-luciferase reporter assay was employed to validate the binding relationship of GAS5/miR-221-3p and miR-221-3p/cyclin-dependent kinase inhibitor 2B (CDKN2B). Western blot was conducted to measure the protein level of CDKN2B.

RESULTS

Our results displayed that GAS5 was downregulated, while miR-221-3p was upregulated in FTC tissues and cells. What's more, overexpression of GAS5 or miR-221-3p inhibition induced G0/G1 phase arrest and inhibited cell proliferation of FTC cells. GAS5 acted as a sponge of miR-221-3p, and CDKN2B was a target gene of miR-221-3p. Additionally, GAS5 inhibited cell cycle and proliferation of FTC cells via reducing miR-221-3p expression to enhance CDKN2B expression.

CONCLUSION

GAS5 induced G0/G1 phase arrest and inhibited cell proliferation via targeting miR-221-3p/CDKN2B axis in FTC. Thus, GAS5 may be a potential therapeutic target for the treatment of FTC.

MiR-221-3p and miR-92a-3p enhances smoking-induced inflammation in COPD

Background

Smoking is likely to facilitate airway inflammation and finally contributes to chronic obstructive pulmonary disease (COPD). This investigation was intended to elucidate miRNAs that were involved in smoking‐induced COPD.

Methods

Altogether 155 COPD patients and 77 healthy volunteers were recruited, and their serum levels of miR‐221‐3p and miR‐92a‐3p were determined. Besides, human bronchial epithelial cells (16HBECs) were purchased, and they were treated by varying concentrations of cigarette smoke extract (CSE). The 16HBECs were, additionally, transfected by miR‐221‐3p mimic, miR‐92a‐3p mimic, miR‐221‐3p inhibitor or miR‐92a‐3p inhibitor, and cytokines released by them, including TNF‐α, IL‐8, IL‐1β, and TGF‐β1, were monitored using enzyme linked immunosorbent assay (ELISA) kits.

Results

Chronic obstructive pulmonary disease patients possessed higher serum levels of miR‐221‐3p and miR‐92a‐3p than healthy volunteers (p < 0.05), and both miR‐221‐3p and miR‐92a‐3p were effective biomarkers in diagnosing stable COPD from acute exacerbation COPD. Moreover, viability of 16HBECs was undermined by CSE treatment (p < 0.05), and exposure to CSE facilitated 16HBECs’ release of TNF‐α, IL‐8, IL‐1β, and TGF‐β1 (p < 0.05). Furthermore, miR‐221‐3p/miR‐92a‐3p expression in 16HBECs was significantly suppressed after transfection of miR‐221‐3p/miR‐92a‐3p inhibitor (p < 0.05), which abated CSE‐triggered increase in cytokine production and decline in viability of 16HBECs (p < 0.05).

Conclusion

MiR‐221‐3p and miR‐92a‐3p were involved in CSE‐induced hyperinflammation of COPD, suggesting that they were favorable alternatives in diagnosing COPD patients with smoking history.

LncRNA GAS5 modulates the progression of non-small cell lung cancer through repressing miR-221-3p and up-regulating IRF2

BACKGROUND

Long non-coding RNA growth arrest specific 5 (GAS5) is a regulator in non-small cell lung cancer (NSCLC) progression. Nonetheless, the mechanism by which GAS5 exerts its biological function in NSCLC cells remains unclear.

METHODS

GAS5, miR-221-3p relative expression levels in NSCLC tissues and cells were examined by qPCR. After gain-of-function and loss-of-function models were established, the viability of H1299 and A549 cells were examined by CCK-8 and EdU assays. Cell migration and invasion were examined by the Transwell experiment. The binding sequence of GAS5 for miR-221-3p was confirmed by the dual-luciferase reporter gene experiment. The regulatory function of GAS5 and miR-221-3p on IRF2 was investigated by Western blot.

RESULTS

GAS5 expression was down-modulated in NSCLC tissues and cell lines. GAS5 overexpression restrained the proliferation, migration and invasion of NSCLC cells, while miR-221-3p, which was targeted and negatively modulated by GAS5, worked oppositely. Restoration of miR-221-3p markedly reversed the effects of GAS5 on NSCLC cells. Additionally, GAS5 increased IRF2 expression in NSCLC cells by repressing miR-221-3p.

CONCLUSIONS

GAS5 blocks the progression of NSCLC partly via increasing IRF2 expression level via repressing miR-221-3p.

Bioinformatics analysis of the expression and role of microRNA-221-3p in head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide, associated with a high rate of morbidity and mortality. However, the target genes of miR-221-3p and the underlying mechanism involved in HNSCC are still not clear. Therefore, in the current study, we studied the role of miR-221-3p in the HNSCC.

METHODS

Tissues collected from 48 control and 21 HNSCC patients were processed to check the differential expression of miR-221-3p by RT-qPCR. Overexpression of microRNA-221-3p (miR-221-3p) is significantly correlated to the onset and progression of HNSCC. We also conducted the meta-analysis of the cancer literature from the cancer genome atlas (TCGA) and the Gene Expression Omnibus (GEO) database to estimate the expression of miR-221-3p in HNSCC. The miR-221-3p target genes in the HNSCC were predicted with the miRWalk and TCGA databases, and functionally annotated via the Gene Ontology. Finally, Spearman's analysis was used to determine the role of the related target genes in important pathways involved in the development of HNSCC.

RESULTS

We observed a significantly higher expression of miR-221-3p in HNSCC compared to the normal with a summary receiver operating characteristic (sROC) of 0.86(95% Cl: 0.83,0.89). The KEGG and GO comprehensive analysis predicted that miR-221-3p might be involved in the development of HNSCC through the following metabolic pathways, viz. Drug metabolism - cytochrome P450 UGT1A7 and MAOB may be important genes for the role of miR-221-3p.

CONCLUSION

Based on bioinformatics analysis, our results indicate that miR-221-3p may be used as a non-invasive and hypersensitive biomarker in the diagnosis. Thus, it can be concluded that miR-221-3p may be an extremely important gene locus involved in the process of the deterioration and eventual tumorigenesis of HNSCC. Hopefully, additional work will validate its usefulness as a target for future clinical research.

miR-221-3p regulates apoptosis of ovarian granulosa cells via targeting FOXO1 in older women with diminished ovarian reserve (DOR)

In our earlier study, we showed that the expression of microRNA‐221‐3p (miR‐221‐3p) was significantly lower in women of advanced age with diminished ovarian reserve (DOR) compared with young women with normal ovarian reserve (NOR). Therefore, in this study, we aimed to explore how miR‐221‐3p regulates apoptosis of granulosa cells and the pathogenesis of DOR. Bioinformatics prediction and dual‐luciferase reporter assay were conducted to identify the target gene of miR‐221‐3p. miR‐221‐3p expression was manipulated by transfecting KGN cells with miR‐221‐3p mimics, inhibitor, and negative control. Following transfection, apoptosis of granulosa cells was determined by flow cytometry, and the expression of the target gene was measured by quantitative real‐time polymerase chain reaction (qRT‐PCR) and western blot analysis (WB). In addition, the expression of the target gene in granulosa cells of DOR patients and NOR patients was measured. miR‐221‐3p were found to directly bind the 3ʹ untranslated region of Forkhead box O1 (FOXO1). Transfection with miR‐221‐3p mimics significantly decreased the apoptosis rate of KGN cells compared with transfection with miR‐221‐3p inhibitors. The expression level of miR‐221‐3p was negatively correlated with the messenger RNA and protein levels of the FOXO1 gene. Besides, FOXO1 expression was upregulated in DOR patients. In conclusion, these results provide evidence that downregulation of miR‐221‐3p expression promotes apoptosis of granulosa cells by upregulating FOXO1 expression, thus serving an important role in DOR pathogenesis.

miR-221-3p promotes hepatocellular carcinogenesis by downregulating O6-methylguanine-DNA methyltransferase

This study aimed to investigate the influence of miR-221-3p and O⁶-methylguanine-DNA methyltransferase (MGMT) interaction in human hepatocellular carcinoma (HCC), thereby revealing a novel molecular mechanism of hepatic carcinogenesis involving miR-221-3p and MGMT.

Fluorescence qPCR and immunoblot assays were performed to determine the expression of RNA and protein in HCC tissues and cell lines. We also employed the firefly and Renilla luciferase assay to verify the target relationship between miR-221-3p and MGMT mRNA. Assessments including the MTT assay, wound-healing assay, transwell assay, colony foci formation experiment, and flow cytometric experiment were carried out to determine the viability, migration, invasion, proliferation, cell cycle progression, and apoptosis of SMMC-7721 and BEL-7404 cell lines with the modulated expression of miR-221-3p and MGMT. Compared to healthy tissues and cell line HL7702, miR-221-3p was significantly upregulated but MGMT was significantly downregulated in carcinomas and cancerous cell lines. Forced miR-221-3p overexpression was found to enhance the proliferation, migration, invasion, and clonogenicity of cell lines, but it suppressed cell apoptosis. Findings also revealed that forced miR-221-3p overexpression had little effect on cell cycle progression. After MGMT was confirmed to be atarget gene of miR-221-3p, it was found that the forced upregulation of miR-221-3p downregulated MGMT mRNA and protein levels significantly. MiR-221-3p was identified as an HCC promoting factor, and it specifically inhibited the expression of the MGMT. Besides, the upregulation of miR-221-3p had apositive influence on HCC pathogenesis by inhibiting MGMT expression.

Study on the ameliorating effect of miR-221-3p on the nerve cells injury induced by sevoflurane

PURPOSE

Sevoflurane is a widely used anesthetics, however, it has been reported that sevoflurane has neurotoxic effects. Studies have shown that miR-221-3p can ameliorate neuron damage. This study was to investigate whether miR-221-3p could reduce the neurotoxic effect of sevoflurane on nerve cells.

MATERIALS AND METHODS

The rat hippocampal neuron cells were treated with sevoflurane or cultured normally. And we constructed neuron cells that overexpressed or low expression of miR-221-3p in the presence or absence of sevoflurane. The cells were transfected with CDKN1B or siCDKN1B, and co-transfected with miR-221-3p mimic and CDKN1B or miR-221-3p inhibitor and siCDKN1B. Cell viability and apoptosis were detected by CCK-8 and flow cytometer. Target gene of miR-221-3p were predicted by TargetScan and luciferase reporter assay. The expressions of related genes were detected by western blotting and quantitative real-time polymerase chain reaction.

RESULTS

Sevoflurane decreased miR-221-3p level and increased CDKN1B level, inhibited cell viability and promoted apoptosis. Overexpress of miR-221-3p decreased CDKN1B level, up-regulated cell viability and inhibited apoptosis, and reversed the effects of sevoflurane on cell viability and apoptosis, while the effects low expression of miR-221-3p was contrary. CDKN1B was the target gene of miR-221-3p, which inhibited cell viability and promoted apoptosis, and reversed the effects of miR-221-3p mimic, whereas siCDKN1B did the opposite effects.

CONCLUSIONS

Sevoflurane can cause nerve cell injury, and miR-221-3p may promote cell activity and inhibit apoptosis by inhibiting CDKN1B expression, thereby ameliorating cell injury induced by sevoflurane.

miR-221-3p and miR-222-3p downregulation promoted osteogenic differentiation of bone marrow mesenchyme stem cells through IGF-1/ERK pathway under high glucose condition

OBJECTIVE

This study aims to investigate the roles of miR-221-3p and miR-222-3p in the regulation of osteogenic differentiation of bone marrow mesenchyme stem cells (BMSCs) under high glucose condition.

MATERIALS AND METHODS

The expreesions of miR-221-3p, miR-222-3p and insulin-like growth factor 1 (IGF-1) were detected by qRT-PCR. The protein levels of osteoblast-related proteins (Osterix, Runx-2 and Osteopontin) were detected by western blot. Whether miR-221-3p and miR-222-3p can target IGF-1 was assessed by dual luciferase reporter gene assay.

RESULTS

miR-221-3p and miR-222-3p were up-regulated in the mandibles of diabetic rats and BMSCs cultured in high glucose condition. Silencing miR-221-3p or/ and miR-222-3p increased ALP activity and up-regulated osteoblast-related protein levels, and the simultaneous silence the two miRNAs showed stronger effects on ALP activity and osteoblast-related protein levels. Next, we confirmed that miR-221-3p and miR-222-3p both targeted IGF-1 and cooperatively regulated its expression. Besides, miR-221-3p and miR-222-3p regulated ERK activation through IGF-1. Silencing miR-221-3p and miR-222-3p promoted osteogenic differentiation of BMSCs through IGF-1 under high glucose condition.

CONCLUSION

miR-221-3p and miR-222-3p inhibited osteogenic differentiation of BMSCs via IGF-1/ERK pathway under high glucose condition.

LncRNA TUG1 reverses LPS-induced cell apoptosis and inflammation of macrophage via targeting MiR-221-3p/SPRED2 axis

This study aimed to identify the role of lncRNA TUG1 with miR-221-3p on mice with lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS). Animal model was established, and lung tissue histopathologic status and permeability were detected by hematoxylin-eosin (HE) or Evans blue dye assay respectively. Levels of inflammation cytokines, lncRNA TUG1, miR-221-3p, sprouty related EVH1 domain-containing 2 (SPRED2), and phosphorylated (p)-ERK1/2 were determined by ELISA, qRT-PCR or Western blot. Pulmonary impairment and apoptosis were examined by flow cytometry. We observed that LPS up-regulated levels of tumor necrosis factor-α (TNF-α), Interleukin-1β (1L-1β), and ERK1/2 phosphorylation, and reduced SPRED2 levels, which were rescued by overexpressed lncRNA TUG1. StarBase and dual-luciferase reporter assay verified that miR-221-3p was targeted by lncRNA TUG1. MiR-221-3p could reverse the effect of lncRNA TUG1 on cell apoptosis, levels of TNF-α, IL-1β, SPRED2, and p-ERK1/2. Therefore, overexpressed lncRNA TUG1 attenuated LPS-induced pulmonary impairment in ARDS mice via regulating miR-221-3p/SPRED2 axis.

Duck Tembusu Virus Utilizes miR-221-3p Expression to Facilitate Viral Replication via Targeting of Suppressor of Cytokine Signaling 5

Duck Tembusu virus (DTMUV), a member of Flaviviridae family, causes acute egg-drop syndrome in ducks. MicroRNAs (miRNAs) have been found to be involved in various biological processes, including tumor genesis, viral infection, and immune response. However, the functional effect of miRNAs on DTMUV replication remains largely unclear. This study aimed to elucidate the role of host microRNA-221-3p (miR-221-3p) in regulating DTMUV replication. Here, we indicated that the expression of miR-221-3p was significantly upregulated in duck embryo fibroblasts (DEFs) during DTMUV infection. Transfection of miR-221-3p mimic significantly reduced interferon (IFN) β production, whereas transfection of miR-221-3p inhibitor conversely significantly increased the expression of IFN-β in DTMUV-infected DEF. Moreover, we found that viral RNA copies, viral E protein expression level, and virus titer, which represent the replication and proliferation of virus, were all enhanced when transfecting the miR-221-3p mimic into DEF; reverse results were also observed by transfecting the miR-221-3p inhibitor. We also found that the expression of suppressor of cytokine signaling 5 (SOCS5) was downregulated in DEF infected with DTMUV. Besides, we further proved that SOCS5 is a target of miR-221-3p and that miR-221-3p could negatively modulate SOCS5 expression at both mRNA and protein levels. Finally, our results showed that overexpression of SOCS5 inhibited DTMUV replication and knockdown of SOCS5 enhanced DTMUV replication. Thus, our findings reveal a novel host evasion mechanism adopted by DTMUV via miR-221-3p, which may hew out novel strategies for designing miRNA-based vaccines and therapies.

miR-221-3p Delivered by BMMSC-Derived Microvesicles Promotes the Development of Acute Myelocytic Leukemia

Objective: The study aims to investigate the effects of miR-221-3p in bone marrow mesenchymal stem cell (BMMSC)-derived microvesicles (MVs) on cell cycle, proliferation and invasion of acute myelocytic leukemia (AML).

Methods: Bioinformatics was used to predict differentially expressed miRNAs (DEmiRNAs) in AML. The morphology of BMMSC-derived MVs was observed under an electron microscope, and the positional relation of MVs and OCI-AML2 cells was observed by a fluorescence microscope. MTT, Transwell, and flow cytometry assays were used to analyze the effects of MVs on OCI-AML2 cells. The targeted relationship between miR-221-3p and CDKN1C was detected by dual luciferase assay.

Results: It was verified that miR-221-3p promoted the proliferation, invasion and migration of OCI-AML2 cells, and induced the cell cycle arrest in G1/S phase as well as inhibited cell apoptosis. Further studies showed that MVs promoted the proliferation, migration and invasion of AML, and induced the cell cycle arrest in G1/S phase through miR-221-3p. It was confirmed that miR-221-3p can directly target CDKN1C to regulate cell cycle, proliferation and invasion of AML.

Conclusion: miR-221-3p in BMMSC-derived MVs regulated AML cell cycle, cell proliferation and invasion through targeting CDKN1C. miR-221-3p and CDKN1C were considered to be potential targets and biomarkers for the treatment of AML in clinic.

The lncRNA-GAS5/miR-221-3p/DKK2 Axis Modulates ABCB1-Mediated Adriamycin Resistance of Breast Cancer via the Wnt/β-Catenin Signaling Pathway

Drug resistance, including adriamycin (ADR)-based therapeutic resistance, is a crucial cause of chemotherapy failure in breast cancer treatment. Acquired chemoresistance has been identified to be closely associated with the overexpression of P-glycoprotein (P-gp/ABCB1). Long non-coding RNA (lncRNA) growth arrest-specific 5 (GAS5) can be involved in carcinogenesis; however, its roles in ABCB1-mediated ADR resistance are poorly understood. In this study, we identified a panel of differentially expressed lncRNAs, mRNAs, and microRNAs (miRNAs) in MCF-7 and MCF-7/ADR cell lines through RNA sequencing (RNA-seq) technologies. GAS5 level was downregulated whereas ABCB1 level was upregulated in the resistant breast cancer tissues and cells. Overexpression of GAS5 significantly enhanced the ADR sensitivity and apoptosis, and it inhibited the efflux function and expression of ABCB1 in vitro, while knockdown of GAS5 had the opposite effects. Further mechanism-related investigations indicated that GAS5 acted as an endogenous “sponge” by competing for miR-221-3p binding to regulate its target dickkopf 2 (DKK2), and then it inhibited the activation of the Wnt/β-catenin pathway. Functionally, GAS5 enhanced the anti-tumor effect of ADR in vivo. Collectively, our findings reveal that GAS5 exerted regulatory function in ADR resistance possibly through the miR-221-3p/DKK2 axis, providing a novel approach to develop promising therapeutic strategy for overcoming chemoresistance in breast cancer patients.

miR-221-3p and miR-15b-5p promote cell proliferation and invasion by targeting Axin2 in liver cancer

Globally, liver cancer has the third highest mortality rate among all types of cancer due to the invasive and metastatic capacities of liver tumor cells. MicroRNA (miR) is a class of non-coding RNAs that participate in the development of liver cancer. The aim of the present study was to explore the molecular mechanisms by which miR-221-3p and miR-15b-5p promote the proliferation and invasion of liver cancer cells through targeting axis formation inhibitor 2 (Axin2) and to identify suitable targets for the treatment of liver cancer. The expression levels of miR-221-3p and miR-15b-5p were determined in liver cancer tissues and cells by quantitative PCR, and the association between miR-221-3p, miR-15b-5p and Axin2 expression in liver cancer cells was analyzed using cell transfection. The results demonstrated that miR-221-3p and miR-15b-5p levels were upregulated in liver cancer tissues and cell lines, and results from predictive bioinformatic analysis and identification revealed that Axin2 was the common target gene of miR-221-3p and miR-15b-5p. miR-221-3p and miR-15b-5p may be used as prognostic indicators for liver cancer. The miR-221-3p/miR-15b-5p-Axin2 axis may serve as a therapeutic target in patients with liver cancer.

Serum miR-221-3p as a new potential biomarker for depressed mood in perioperative patients

MicroRNAs (miRNAs) modulate various genes associated with brain disorders and circulating miRNAs may therefore serve as biomarkers for these neurological diseases. We previously found that the miRNA miR-221-3p was highly expressed in cerebrospinal fluid and the serum of major depressive disorder (MDD) patients. Here, we examined whether miR-221-3p could be used as a biomarker for depressed mood in perioperative patients. We first examined the relative expression of serum miR-221-3p by real-time quantitative PCR in perioperative patients with different degrees of depressive mood assessed by the Patient Health Questionnaire-9 (PHQ-9) diagnostic form. We found that miR-221-3p expression in the mild depressive mood group (PHQ-9 scores 5-9) was 2.21 fold that of the normal group (PHQ-9 scores 0-4) and the moderate＆severe depressive mood group (PHQ-9 scores ≥ 10) showed miR-221-3p expression levels 3.66 fold that of the normal group. Then the absolute quantification of serum miR-221-3p was obtained using an miRNA standard curve. We found that the amount of serum miR-221-3p was positively correlated with depressed mood; when serum miR-221-3p > 1.7 × 10⁷ copies/μg RNA, all indicated PHQ-9 scores were higher than 6. Subsequently, we found that miR-221-3p could indirectly increase the expression of IFN-α (Interferon alpha) in astrocytes by targeting IRF2 (Interferon Regulatory Factor 2) and that miR-221-3p participated in the anti-neuroinflammatory signaling cascades induced by ketamine and paroxetine via the IRF2/IFN-α pathway. Our results indicate that elevated serum miR-221-3p can be used as a biomarker for depressed mood in perioperative patients and that IFN-α-induced NF-κB activation in astrocytes mediated by miR-221-3p targeting of IRF2 may be one of the potential mechanisms.

Potential of C1QTNF1-AS1 regulation in human hepatocellular carcinoma

The aim of our study is to explore the regulation of C1QTNF1-AS1 on its target miR-221-3p/SOCS3 in human hepatocellular carcinoma (HCC). To explore the underlying molecular regulation of non-coding RNA for HCC, differentially expressed patterns of lncRNAs and genes were examined by RNA-seq. GO and KEGG pathway analysis were done based on the function of mRNAs that mediated by differentially expressed lncRNAs. RT-qPCR and western blot were conducted to detect the mRNA and protein level expression of C1QTNF1-AS1, miR-221-3p, SOCS3 and key proteins in JAK/STAT signaling pathway in HCC tissues and cells. The target miRNA of differentially expressed C1QTNF1-AS1 and SOCS3 was miR-221-3p predicted by bioinformatics analysis. C1QTNF1-AS1 and SOCS3 was downregulated and miR-221-3p was upregulated in HCC tissues and cells. In HepG2 and Huh-7 cells, the overexpression of C1QTNF1-AS1 or SOCS3, and silencing of miR-221-3p inhibited proliferation, migration, invasion and JAK/STAT signaling pathway, while promoted cell apoptosis. The results of dual-luciferase assay indicated that C1QTNF1-AS1 regulated miR-221-3p and miR-221-3p targeted SOCS3 by directly binding. And the growth of HCC in vivo was impeded when C1QTNF1-AS1 was upregulated. Overexpression of C1QTNF1-AS1 could downregulate miR-221-3p thereby inhibited the proliferation, migration and invasion of HCC cells.

C1QTNF1-AS1 regulates the occurrence and development of hepatocellular carcinoma by regulating miR-221-3p/SOCS3

BACKGROUND

The aim of our study was to explore how C1QTNF1-AS1 regulated miR-221-3p/SOCS3 axis in human hepatocellular carcinoma (HCC).

METHODS

Differentially expressed lncRNAs and genes were examined via RNA-seq. GO analysis and KEGG pathway enrichment analysis were carried out based on the function of dys-regulated mRNAs. RT-qPCR was employed to detect the relative mRNA expression level of C1QTNF1-AS1, miR-221-3p, SOCS3 and key genes in the JAK/STAT signaling pathway in HCC tissues and cells, and western blot analysis was conducted to detect the relative protein expression levels of SOCS3 and key proteins in the JAK/STAT signaling pathway in HCC tissues and cells. MTT assay, transwell assay and flow cytometry were utilized to assess HCC cell proliferation, invasion, migration and apoptosis. Dual luciferase reporter gene assay was used to verify the targeted relationship between C1QTNF1-AS1 and miR-221-3p, as well as between miR-221-3p and SOCS3. A tumorigenicity assay in nude mice was conducted to investigate the effects of C1QTNF1-AS1 on HCC tumor growth in vivo.

RESULTS

C1QTNF1-AS1 and SOCS3 were down-regulated, while miR-221-3p was up-regulated in HCC tissues and cells. In HepG2 and Huh7 cells, overexpression of C1QTNF1-AS1 or SOCS3, as well as silence of miR-221-3p inhibited HCC cell proliferation, migration, and invasion and promoted HCC cell apoptosis. The results of the dual luciferase reporter gene assay indicated that miR-221-3p could directly target both C1QTNF1-AS1 and SOCS3. In addition, up-regulation of C1QTNF1-AS1 suppressed HCC tumor growth in vivo.

CONCLUSION

Overexpression of C1QTNF1-AS1 down-regulated miR-221-3p and subsequently up-regulated SOCS3, thereby inhibiting HCC cell proliferation, migration and invasion and promoting apoptosis through the JAK/STAT signaling pathway.

Cancer-derived exosomal miR-221-3p promotes angiogenesis by targeting THBS2 in cervical squamous cell carcinoma

AIMS

Recently, cancer-derived exosomes were shown to have pro-metastasis function in cancer, but the mechanism remains unclear. Angiogenesis is essential for tumor progression and is a great promising therapeutic target for advanced cervical cancer. Here, we investigated the role of cervical cancer cell-secreted exosomal miR-221-3p in tumor angiogenesis.

METHODS AND RESULTS

miR-221-3p was found to be closely correlated with microvascular density in cervical squamous cell carcinoma (CSCC) by evaluating the microvascular density with immunohistochemistry and miR-221-3p expression with in situ hybridization in clinical specimens. Using the groups of CSCC cell lines (SiHa and C33A) with miR-221-3p overexpression and silencing, the CSCC exosomes were characterized by electron microscopy, western blotting, and fluorescence microscopy. The enrichment of miR-221-3p in CSCC exosomes and its transfer into human umbilical vein endothelial cells (HUVECs) were confirmed by qRT-PCR. CSCC exosomal miR-221-3p promoted angiogenesis in vitro in Matrigel tube formation assay, spheroid sprouting assay, migration assay, and wound healing assay. Then, exosome intratumoral injection indicated that CSCC exosomal miR-221-3p promoted tumor growth in vivo. Thrombospondin-2 (THBS2) was bioinformatically predicted to be a direct target of miR-221-3p, and this was verified by using the in vitro and in vivo experiments described above. Additionally, overexpression of THBS2 in HUVECs rescued the angiogenic function of miR-221-3p.

CONCLUSIONS

Our results suggest that CSCC exosomes transport miR-221-3p from cancer cells to vessel endothelial cells and promote angiogenesis by downregulating THBS2. Therefore, CSCC-derived exosomal miR-221-3p could be a possible novel diagnostic biomarker and therapeutic target for CSCC progression.

Downregulation of EIF5A2 by miR-221-3p inhibits cell proliferation, promotes cell cycle arrest and apoptosis in medulloblastoma cells

Recently, miR-221-3p expression has been reported to be down-regulated in medulloblastoma (MB), but its functional effects remains unclear. In this study, quantitative real-time PCR (qRT-PCR) revealed significantly decreased miR-221-3p in MB cell lines. Transfection of miR-221-3p mimics reduced, or inhibitor increased cell proliferation in MB cells using MTT assay. Flow cytometry analysis indicated miR-221-3p overexpression promoted, while knockdown alleviated G0/G1 arrest and apoptosis. Luciferase reporter assay confirmed miR-221-3p directly targets the EIF5A2 gene. Moreover, restoration of EIF5A2 in the miR-221-3p-overexpressing DAOY cells significantly alleviated the suppressive effects of miR-221-3p on cell proliferation, cell cycle and apoptosis. Furthermore, miR-221-3p overexpression decreased CDK4, Cyclin D1 and Bcl-2 and increased Bad expression, which was reversed by EIF5A2 overexpression. These results uncovered the tumor suppressive role of miR-221-3p in MB cell proliferation at least in part via targeting EIF5A2, suggesting that miR-221-3p might be a potential candidate target for diagnosis and therapeutics of MB.

MiR-221-3p is down-regulated in preeclampsia and affects trophoblast growth, invasion and migration partly via targeting thrombospondin 2

Preeclampsia (PE) is a common obstetrical disorder characterized by hypertension and proteinuria. The aberrant expression of miR-221-3p in placental tissues has been implicated in the pathogenesis of PE. This study examined the role of miR-221-3p in trophoblast growth, invasion and migration, and explored the underlying mechanisms. Our results showed that miR-221-3p was down-regulated in placental tissues from PE patients compared to heathy controls as measured by quantitative real-time PCR assay. CCK-8 assay, Transwell invasion assay and wound healing assay showed that miR-221-3p overexpression promoted trophoblast (HTR-8/SVneo cells) growth, invasion and migration, and knockdown of miR-221-3p exerted the opposite effects. Flow cytometry experiments further demonstrated that miR-221-3p overexpression inhibited apoptosis, increased cell population at S phase, and decreased cell population at G₀/G₁ phase of HTR-8/SVneo cells; while miR-221-3p knockdown exerted the opposite effects. Bioinformatics prediction and luciferase reporter assay showed that miR-221-3p targeted the 3' untranslated region of thrombospondin 2 (THBS2), and qRT-PCR and western blot assays revealed that miR-221-3p negatively regulated the expression of THBS2 in HTR-8/SVneo cells. Furthermore, overexpression of THBS2 attenuated the in vitro effects of miR-221-3p overexpression on cell growth, invasion and migration of HTR-8/SVneo cells. The clinical sample analysis showed that the mRNA expression levels of THBS2 was significantly increased in placental tissues from PE patients and was negatively correlated with expression levels of miR-221-3p. In summary, our results demonstrated that miR-221-3p was down-regulated in PE, and the in vitro functional assays revealed that miR-221-3p promoted trophoblast growth, invasion and migration partly via targeting THBS2.

miR-221-3p inhibits oxidized low-density lipoprotein induced oxidative stress and apoptosis via targeting a disintegrin and metalloprotease-22

Oxidized low-density lipoprotein (ox-LDL)-induced oxidative stress and apoptosis are considered as a critical contributor to atherosclerosis. MicroRNAs (miRNAs) have been reported versatile functions in all biological processes via directly suppressing target messenger RNA at a posttranscriptional level. Although miRNA-221 has been implied to be involved in the regulation of atherosclerosis, the underlying mechanism remains unclear. Here, we showed that ox-LDL treatment remarkably suppressed the expression of miR-221-3p in a concentration-dependent and time-dependent manner. Transfection of miR-221-3p mimic significantly reduced the foam cell formation and expression of lipid biomarkers, while transfection of the miR-221-3p inhibitor showed completely opposite effects. Moreover, miR-221-3p was also found to inhibit the process of cell apoptosis in macrophages. A disintegrin and metalloprotease-22 (ADAM22) is predicted as a direct target of miR-221-3p, and silencing AMAM22 resulted in a reduced foam cell formation and cell apoptosis. Furthermore, silencing AMAM22 restored the stimulatory effect of the miR-221-3p inhibitor in ox-LDL-induced foam cell formation and apoptosis. These findings suggest that miR-221-3p inhibits ox-LDL and apoptosis via directly targeting ADAM22.

miR-221-3p Inhibits Schwann Cell Myelination

Following peripheral nerve injury, Schwann Cells (SCs) undergo dedifferentiation, proliferation, migration, and remyelination. Recent works demonstrated the importance of the short non-coding RNA (miRNAs) in SC dedifferentiation and remyelination after nerve injury. Previously, we found some miRNAs like miR-9, miR-221, miR-222 and miR-182 could regulate the proliferation and migration of SCs. Therefore, it is imperative to ask whether these miRNAs could regulate the myelination of SCs. Here we demonstrated that miR-221-3p could inhibit the myelination of SCs when co-cultured with dorsal root ganglion cells in vitro. In addition, NGF1-A binding protein 1 (Nab1) which was essential for SCs myelination could be downregulated by miR-221-3p. Suppressing the expression of Nab1 could reverse the promotion of miR-221-3p antagomir on SC myelination. The effects of miR-221-3p on SC myelination might be used to improve peripheral nerve regeneration, thus offering a new approach to peripheral nerve repair.

Downregulation of miR-221-3p and upregulation of its target gene PARP1 are prognostic biomarkers for triple negative breast cancer patients and associated with poor prognosis

The purpose of this study was to identify microRNAs (miRNAs) closely associated with the prognosis of triple-negative breast cancer (TNBC) and their possible targets. This study recruited 125 early-stage TNBC patients, including 40 cases in the experimental group (20 cases with poor prognoses vs. 20 cases with good prognoses) and 85 cases in the validation group (27 cases with poor prognoses vs. 58 cases with good prognoses). In the experimental group, miRNA microarray showed 34 differentially expressed miRNAs in patients with different prognoses. We selected 5 miRNAs for validation. The differential expression of miR-221-3p was further verified in the experimental and validation groups using real-time polymerase chain reaction (PCR). High miR-221-3p expression was associated with better 5-year disease-free survival (DFS) (HR = 0.480; 95% CI, 0.263-0.879; p = 0.017) of TNBC patients. High expression of its target gene PARP1 predicted poorer 5-year DFS (HR = 2.236, 95% CI, 1.209-4.136, p = 0.010). MiR-221-3p down-regulated PARP1 by targeting its 3'-untranslated region. In conclusion, low miR-221-3p expression may contribute to the poor outcome of TNBC patients through regulating PARP1. MiR-221-3p likely plays a role as a PARP1 inhibitor by directly regulating PARP1 expression, thereby affecting the prognoses of TNBC patients.

MicroRNA-221-3p is up-regulated and serves as a potential biomarker in pancreatic cancer

It has been demonstrated that circulating MicroRNAs (miRNAs) could be potential biomarkers for cancer diagnosis and prognosis. For pancreatic cancer (PCa), little is known about miR-221-3p biological function or its prognostic value. In the current study, we profiled miR-221-3p expression in PCa cell lines. Compared with normal pancreases ductal epithelial cells, miR-221-3p is up-regulated in all PCa cell lines analysed. In SW1990 cells, overexpression of miR-221-3p increased cell proliferation and inhibited apoptosis, while inhibition of miR-221-3p decreased cell growth rate and promoted apoptosis. Compared with adjacent non-tumour tissues, miR-221-3p was up-regulated in all 21 PCa tissues. Expression level of miR-221-3p was investigated in plasma and statistical analyses showed that circulating miR-221-3p expression level was correlated with distant metastasis and TNM stages. The receiver-operating characteristic (ROC) curves and the area under the ROC curve (AUC) suggested that the diagnostic efficacy for distant metastasis of miR-221-3p is better than CA19-9 (AUC: 0.689 vs. 0.587). To summary, we found miR-221-3p could promote cell proliferation and inhibit apoptosis in PCa cells and circulating miR-221-3p could serve as a biomarker for PCa.

MiRNA-221-3p desensitizes pancreatic cancer cells to 5-fluorouracil by targeting RB1

Pancreatic cancer is a highly lethal disease due to its rapid dissemination and resistance to conventional chemotherapy. MicroRNAs (miRNAs) are emerging as novel regulators of chemoresistance, which modulate the expression of drug resistance-related genes. MiRNA-221 has been reported to be associated with chemoresistance in various types of cancer. But the detailed molecular mechanism about miR-221-3p regulating 5-fluorouracil (5-FU) resistance in human pancreatic cancer remains to be clarified. In this study, we investigated the association between miR-221-3p expression and 5-FU sensitivity. Studies on pancreatic cancer cell lines suggested an increased 5-FU resistance with miR-221-3p over-expression. In addition, the results indicated that miR-221-3p down-regulated RB1 expression by directly binding to its 3'-UTR and therefore caused increased several aspects of pancreatic cancer pathogenesis, including proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT). Collectively, our findings revealed the important role of miR-221-3p in promoting 5-FU resistance of pancreatic cancer cells and provided a potential therapeutic target for pancreatic cancer.

MicroRNA-19b/221/222 induces endothelial cell dysfunction via suppression of PGC-1α in the progression of atherosclerosis

BACKGROUND

Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is a master regulator of cellular energy metabolism that is associated with many cardiovascular diseases, including atherosclerosis. However, the role and underling regulatory mechanisms of PGC-1α in the pathogenesis of atherosclerosis are not completely understood. Here, we identified the microRNAs that post-transcriptionally regulate PGC-1α production and their roles in the pathogenesis of atherosclerosis.

METHODS AND RESULTS

A significant down-regulation of PGC-1α protein was observed in human atherosclerotic vessel samples. Using microarray and bioinformatics analyses, PGC-1α was identified as a common target gene of miR-19b-3p, miR-221-3p and miR-222-3p, which are mainly located in the intima of atherosclerotic vessels. In vitro induction of miR-19b-3p, miR-221-3p and miR-222-3p by the inflammatory cytokines TNFα and IFNγ may affect PGC-1α protein production and consequently result in mitochondrial dysfunction in Human Aortic Endothelial Cells (HAECs). The overexpression of miR-19b-3p, miR-221-3p and miR-222-3p in HAECs caused intracellular ROS accumulation, which led to cellular apoptosis.

CONCLUSION

Taken together, these results demonstrate that PGC-1α plays a protective role against the vascular complications of atherosclerosis. Moreover, the posttranscriptional regulation of PGC-1α by miR-19b/221/222 was unveiled, which provides a novel mechanism in which a panel of microRNAs can modulate endothelial cell apoptosis via the regulation mitochondrial function.

Prognostic value of miR-221-3p, miR-342-3p and miR-491-5p expression in colon cancer

Increasing evidence has demonstrated that microRNAs (miRNAs) are involved in colon cancer initiation and progression, and may serve as diagnostic and prognostic biomarkers for colon cancer. Here, we investigated the levels of miR-9-1, miR-203-3p, miR-221-3p, miR-342-3p, miR-491-5p and miR-503-5p in 90 pairs of colon cancer and adjacent normal tissues, and explored the relationship between their expression and clinical outcome of colon cancer. Five miRNAs (miR-203-3p, miR-221-3p, miR-342-3p, miR-491-5p and miR-503-5p) were dysregulated in colon cancer tissue (P < 0.05). The levels of miR-503-5p in larger tumors (≥ 6 cm) were higher than those in smaller ones (< 6 cm) (P = 0.031), while the levels of miR-203-3p and miR-491-5p in patients aged 70 years and older were higher than those in patients aged younger than 70 years (P = 0.019 and 0.049, respectively). The high levels of miR-221-3p (HR = 2.416, 95% CI 1.314-4.445, P = 0.005), miR-342-3p (HR = 1.807, 95% CI 1.003-3.253, P = 0.049) and miR-491-5p (HR = 1.868, 95% CI 1.032-3.384, P = 0.039) were significantly associated with worse survival time. Moreover, combination analysis of miR-221-3p, miR-342-3p and miR-491-5p expression revealed that patients with 3 highly expressed miRNAs had lower survival rates compared with those with zero-to-two highly expressed miRNAs (HR = 2.100, 95% CI 1.157-3.813, P = 0.015), especially those with TNM stages I and II (HR = 4.204,95% CI 1.762-10.030, P = 0.001). Our results suggest that the three-miRNA signature may help doctors better predict prognosis and guide treatment decisions for colon cancer.