miRNA-21 Inhibitor Research Articles

Gualou Guizhi decoction promotes therapeutic angiogenesis via the miR210/HIF/VEGF pathway in vivo and in vitro

Context Gualou Guizhi decoction (GLGZD) is an ancient Chinese classical prescription widely used to treat ischemic stroke. However, the molecular mechanisms of GLGZD promoting angiogenesis are unavailable. Objective This study investigates the angiogenesis effect of GLGZD as well as its mechanism. Materials and methods Ischemic stroke was established by middle cerebral artery occlusion/reperfusion (MCAO/R) in male Sprague-Dawley (SD) rats. The GLGZD groups received GLGZD (3.6, 7.2 and 14.4 g/kg) orally. Oxygen-glucose deprivation/reoxygenation (OGD/R) model was constructed in HUVECs receiving GLGZD medicated serum (MS). MRI, H&E staining, qRT-PCR, western blot and immunofluorescence methods were employed. miRNA210 inhibitor was employed to confirm the effects of GLGZD on promoting angiogenesis. Dual luciferase assay was used to verify the binding of miRNA210 with HIF mRNA. Results GLGZD treatment improved neurological function (by 27%), alleviated neuronal injury (by 76%), reduced infarct volume (by 74%) and increased microvessel density (by fourfold) in vivo. In vitro data had also shown that GLGZD caused proliferation of the cells (by 58%), their migration, and eventual formation of tubes (by threefold). Simultaneously, GLGZD enhanced the levels of angiogenesis-related molecules and activated the HIF/VEGF signalling pathway. Surprisingly, the beneficial effects of GLGZD on post-stroke angiogenesis and neurological recovery were weakened by miRNA210 inhibitor, and also abolished the mediation of proangiogenic factors. miRNA210 directly targeted HIF mRNA. Discussion and conclusions GLGZD enhances angiogenesis via activation of the miRNA210/HIF/VEGF signalling pathway, suggesting it can be a novel application as an effective angiogenic formula for stroke recovery.

Repair of degenerative nucleus pulposus by polyphenol nanosphere-encapsulated hydrogel gene delivery system

Intervertebral disc degeneration (IDD) progresses due to local inflammatory response, gradually unbalanced anabolic/catabolic activity, and progressive functional impairment within the nucleus pulposus. Antagomir-21, a cholesterol-modified miRNA-21 inhibitor, has potential extracellular matrix (ECM) regenerative ability, but its application for IDD is limited by inadequate local delivery systems. An injectable hydrogel gene delivery system encapsulating a modified tannic acid nanoparticles (TA NPs) vector was engineered for on-demand and sustained delivery of antagomir-21 into the nucleus pulposus. After nucleus pulposus cell uptake, antagomir-21 was released from TA NPs and regulated the ECM metabolic balance by inhibiting the MAPK/ERK signaling pathway. TA NPs scavenged intracellular ROS and reduced inflammation by downregulating TNF-α expression. In vivo, synergistic anti-inflammatory effects and ECM regeneration effectively promoted therapeutic efficacy against IDD. This hydrogel gene delivery system represents a creative, promising strategy for IDD repair.

Multifunctional DNA nanoprobe for tumor-targeted synergistic therapy by integrating chemodynamic therapy with gene silencing.

Due to the high complexity, diversity and heterogeneity of tumor occurrence and development, multi-mode synergistic therapy is more effective than single treatment modes to improve the antitumor efficacy. Also, multifunctional probes are crucial to realize synergistic therapy. Herein, a multifunctional DNA tetrahedron nanoprobe was ingeniously designed to simultaneously achieve chemodynamic therapy (CDT) and gene silencing for synergistic antitumor. The multifunctional DNA tetrahedron nanoprobe, DNA tetrahedron-silver nanocluster-antagomir-21 (D-sgc8-DTNS-AgNCs-Anta-21), integrated a CDT reagent (DNA-AgNCs) and miRNA-21 inhibitor (Anta-21) with a specific recognition probe (aptamer). After targeted entry in cancer cells, D-sgc8-DTNS-AgNCs-Anta-21 silenced endogenous miRNA-21 by Anta-21 and produced highly toxic ˙OH by reacting with H2O2, which induced apoptosis in the tumor cells. The targeted recognition of aptamers led to the concentration-dependent death of HeLa cells. On the contrary, the cell survival rate of normal cells was basically unaffected with an increase in the concentration of D-sgc8-DTNS-AgNCs-Anta-21. Therefore, the diverse functions, biocompatibility and programmability of DNA provide a useful and easy way to assemble multifunctional probes for synergistic therapy.

The pivotal role of miRNA-21 in myocardial metabolic flexibility in response to short- and long-term high glucose treatment: Evidence in human cardiomyocyte cell line

AimmiRNA-21 is a crucial regulator of developing cardiac diseases, but its role is still controversial, and therefore it is necessary to clarify, at cardiac level, its involvement in high glucose induced-acute and chronic cardiac damage. MethodsHuman ventricular cardiac myoblasts AC16, treated and not with miRNA-21 inhibitor, were exposed to high glucose for 2 and 7 days, and the expression of damage markers were investigated. Further, cardiac energetic metabolism was evaluated by measuring both the expression of glucose transporters and lipids regulators. ResultsShort-term high glucose treatment induced a significant increase in miRNA-21 expression (p < 0.05) that was associated with an increase in hydrogen ion flux and energy potential dissipation without any change in energy production or increase in genes expression involved in cellular damage. miRNA-21 reduction observed (p < 0.05) at 7 days of high glucose treatment, induced the activation of damage pathways and compromised mitochondrial function (p < 0.05). ConclusionIn human cardiomyocytes, the abundance of miRNA-21 takes part in first defense mechanism against cardiac insult and its cardioprotective effect depends on time of exposure to injury. Moreover, miRNA-21 regulates mitochondrial respiration and the ability of cells to select the most appropriate substrate for ATP production in given environment.

Sustained gene delivery from inflammation-responsive anti-inflammatory hydrogels promotes extracellular matrix metabolism balance in degenerative nucleus pulposus

The progression of intervertebral disc degeneration (IDD) is characterized by an initial chronic local inflammatory response and ultimately leads to unbalanced anabolic/catabolic activity within the nucleus pulposus (NP). Injectable inflammation-responsive hydrogels have great potential in treating IDD through on-demand local drug delivery. Here, we designed an injectable inflammation-responsive gelatin-based hydrogel for local and sustained delivery of the naturally extracted anti-inflammatory curcumin and a cholesterol-modified miRNA-21 inhibitor (Antagomir-21) to treat IDD. We successfully demonstrated the robust biocompatibility and ideal inflammation-responsive and on-demand drug release properties of hydrogels, as well as the great potential of IDD regeneration. This work proposes the novel inflammation-responsive hydrogel-based curcumin and miRNA delivery systems for the treatment of IDD. • The hydrogel exhibited sensitve inflammation-responsive property (low pH and high ROS). • The on-demand delivered curcumin played strong anti-inflammatory role. • Cholesterol-modified miRNA would sustained release owing to the host-guest interactions with CD. • Antagomir-21 persistently promoted ECM regeneration of NPCs by promoting autophagy activation. • The anti-inflammation and ECM regeneration behavior of hydrogel positively promoted IDD repair.

Design, synthesis, and evaluation of fluoroquinolone derivatives as microRNA-21 small-molecule inhibitors

MicroRNA-21 (miRNA-21) is highly expressed in various tumors. Small-molecule inhibition of miRNA-21 is considered to be an attractive novel cancer therapeutic strategy. In this study, fluoroquinolone derivatives A1–A43 were synthesized and used as miRNA-21 inhibitors. Compound A36 showed the most potent inhibitory activity and specificity for miRNA-21 in a dual-luciferase reporter assay in HeLa cells. Compound A36 significantly reduced the expression of mature miRNA-21 and increased the protein expression of miRNA-21 target genes, including programmed cell death protein 4 (PDCD4) and phosphatase and tensin homology deleted on chromosome ten (PTEN), at 10 μM in HeLa cells. The Cell Counting Kit-8 assay (CCK-8) was used to evaluate the antiproliferative activity of A36; the results showed that the IC50 value range of A36 against six tumor cell lines was between 1.76 and 13.0 μM. Meanwhile, A36 did not display cytotoxicity in BEAS-2B cells (lung epithelial cells from a healthy human donor). Furthermore, A36 significantly induced apoptosis, arrested cells at the G0/G1 phase, and inhibited cell-colony formation in HeLa cells. In addition, mRNA deep sequencing showed that treatment with A36 could generate 171 dysregulated mRNAs in HeLa cells, while the expression of miRNA-21 target gene dual-specificity phosphatase 5 (DUSP5) was significantly upregulated at both the mRNA and protein levels. Collectively, these findings demonstrated that A36 is a novel miRNA-21 inhibitor.

Endometrial Cancer Cells Promote M2-Like Macrophage Polarization by Delivering Exosomal miRNA-21 under Hypoxia Condition.

Increasing evidence has demonstrated that hypoxia was an aggressive feature in endometrial cancer (EC), which is significantly associated with the tumor grade, lymph node metastasis, and tumor resistance to chemotherapy. However, the relationship between hypoxia and the immune microenvironment in EC is not very clear. Exosomes are small membrane vesicles secreted from a variety of cell types which mediate cell-to-cell communication through transported biomolecules. Here, we investigated whether exosomes can play an immunomodulatory role in intercellular communication between EC cells and macrophages. EC KEL cells were cultured under hypoxia or normoxic condition to collect exosomes. After identification, the exosomes derived from hypoxic or normoxic KEL cells were cultured with the monocyte cell line THP-1 to study the immunoregulation function of KEL cells. The results showed that the total number of exosomes produced by hypoxic KEL cells was significantly higher than that in normoxic condition. In addition, hypoxia markedly stimulated the increase in miRNA-21 expression in the exosomes. After coculture, we found that exosomal miRNA-21 could be horizontally transferred into THP-1 cells. And then, the notably enhanced mRNA expression levels of IL-10 and CD206 in THP-1 cells were observed, suggestive of M2 polarization. To further study the effect of miRNA-21-containing exosomes, we transfected miRNA-21 mimics or inhibitor into THP-1 cells. The results showed that miRNA-21 mimics promoted IL-10 and CD206 mRNA expression levels, and the miRNA-21 inhibitor significantly prevented the alteration induced by intake of hypoxic KEL cell-derived exosomes. In summary, we found that endometrial cancer KEL cells in hypoxic condition promoted monocyte THP-1 cell transformation to M2-like polarization macrophages through delivering exosomal miRNA-21, which may be a potential mechanism of the formation of the immune microenvironment in EC progression.

Silencing of microRNA-210 inhibits the progression of liver cancer and hepatitis B virus-associated liver cancer via targeting EGR3

BackgroundThis study was aimed to investigate the regulatory role of microRNA-210 (miRNA-210) on the progression of liver cancer and Hepatitis B virus (HBV)-associated liver cancer.MethodsThe expression of miRNA-210 was detected in liver tissues of HBV-associated cirrhosis and liver cancer, and in HepG2 and HepG2.2.15 cells by qRT-PCR. MiRNA-210 was silenced in HepG2 and HepG2.2.15 cells by the transfection of miRNA-210 inhibitor. The cell viability and apoptosis was detected by MTT assay and Annexin V-fluorescein isothiocyanate/propidium iodide staining, respectively. The protein expression of EGR3 was detected by Western blot. The regulatory relationship between EGR3 and miRNA-210 was predicted by TargetScan and identified by Dual luciferase reporter gene assay.ResultsMiRNA-210 was overexpressed in the liver tissues of HBV-associated cirrhosis and liver cancer, and in HepG2 and HepG2.2.15 cells (P < 0.05). Silencing of miRNA-210 inhibited the viability and promoted the apoptosis of HepG2 and HepG2.2.15 cells (P < 0.05). EGR3 was a target of miRNA-210, which was down-regulated in the liver tissues of HBV-associated cirrhosis and liver cancer, and in HepG2 and HepG2.2.15 cells (P < 0.05). Silencing of miRNA-210 increased the mRNA and protein expression of EGR3 (P < 0.05). Silencing of EGR3 reversed the anti-tumor effect of miRNA-210 inhibitor on HepG2 and HepG2.2.15 cells (P < 0.05).ConclusionsSilencing of miRNA-210 inhibits the progression of liver cancer and HBV-associated liver cancer via up-regulating EGR3.

Engineering blood exosomes for tumor-targeting efficient gene/chemo combination therapy.

Rationale: Developing an effective nanoplatform to realize 'multi-in-one' is essential to broaden the therapeutic potential of combination therapy. Exosomes are ideal candidates since their intrinsic abilities of integrating multiple contents and functions. However, only limited efforts have been devoted to engineering exosomes to integrate the needed properties, also considering the safety and yield, for tumor-targeted and efficient gene/chemo combination therapy.Methods: Herein, by manipulating the exosome membrane, blood exosomes with high abundance and safety are engineered as a versatile combinatorial delivery system, where the doxorubicin (Dox) and cholesterol-modified miRNA21 inhibitor (miR-21i) are co-embedded into the lipid bilayer of exosomes, and the magnetic molecules and endosomolytic peptides L17E are bind to the exosome membrane through ligand-receptor coupling and electrostatic interactions, respectively.Results: It is proved that such engineering strategy not only preserves their intrinsic features, but also readily integrates multiple properties of tumor targeting, efficient transfection and gene/chemo combination therapy into blood exosomes. The lipid bilayer structure of exosomes allows them to co-load Dox and miR-21i with high-payloads. Moreover, profiting from the integration of magnetic molecules and L17E peptides, the engineered exosomes exhibit an enhanced tumor accumulation and an improved endosome escape ability, thereby specifically and efficiently delivering encapsulated cargos to tumor cells. As a result, a remarkable inhibition of tumor growth is observed in the tumor-bearing mice, and without noticeable side effects.Conclusions: This study demonstrates the potential of engineered blood exosomes as feasible co-delivery nanosystem for tumor-targeted and efficient combination therapy. Further development by replacing the drugs combined regimens can potentially make this engineered exosome become a general platform for the design of safe and effective combination therapy modality.

MiR-21 Promotes the Invasion and Metastasis of Gastric Cancer Cells by Activating Epithelial-Mesenchymal Transition

Background: Gastric cancer (GC) is one of the most common malignant tumors. It is likely to occur in lymph nodes and is prone to distant metastasis in its early stages, which portends a poor prognosis. Previous studies have shown that miRNA-21 was abnormally highly expressed and associated with early metastasis in GC, but the mechanism by which it regulates the invasion and metastasis of GC has not been elucidated. Methods: Epithelial-mesenchymal transition (EMT) is an important pathologic basis of tumor invasion and metastasis, and in this study, the relationship between miRNA-21 and EMT in GC invasion and metastasis was investigated using RT-qPCR, Western blot, and wound scratch and transwell assays. Results: We found that miRNA-21 expression in GC cell lines was higher than in a gastric mucosal epithelial cell line. After transfection with an miRNA-21 mimic, the upregulation of EMT was found to promote migration and invasion of MGC-803 cells. However, the downregulation of EMT was found to accompany the inhibition of invasion and migration of GC cells after downregulation of miRNA-21 expression due to the transfection of an miRNA-21 inhibitor. Conclusions: These findings suggest that miRNA-21 might promote the invasion and metastasis of GC by upregulating EMT.

MiRNA-210 induces the apoptosis of neuronal cells of rats with cerebral ischemia through activating HIF-1α-VEGF pathway.

This study aims to explore the expression of micro-ribonucleic acid (miRNA)-210 in the cerebral cortex of rat model with global cerebral ischemia, and determine its function on the regulation of the apoptosis of neuronal cells. Rat models of global cerebral ischemia were established in vitro. Rats were euthanized at 24 h after reperfusion and the cerebral cortex was collected. The expression of miRNA-210 was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Neuronal cells were transfected by liposomes in vitro and cells were divided into neuronal cell group (group i), neuronal cell + miRNA-210 mimic group (group ii) and neuronal cell + miRNA-210 inhibitor group (group iii). The cell apoptosis rate and gene and protein expressions of HIF-1α, VEGF and Caspase-3 were measured. The level of miRNA-210 in rats with global cerebral ischemia was remarkably higher than that in rats from sham operation group (p<0.05). The apoptosis rate of neuronal cells was increased evidently when miRNA-210 was overexpressed, and the expressions of HIF-1α, VEGF and Caspase-3 were elevated markedly at both mRNA and protein levels. Our data indicate that miRNA-210 expression is upregulated in the rats with global cerebral ischemia, and the rise of miRNA-210 level increases the apoptosis of neuronal cells through the activation of HIF-1α-VEGF signaling pathway.

Nucleolin protects against doxorubicin-induced cardiotoxicity via upregulating microRNA-21.

Nucleolin is a multifunctional protein and participates in many important biological processes. Our previous study found that nucleolin protects the heart against myocardial ischemia-reperfusion injury. In this study, we aimed to investigate the role of nucleolin in doxorubicin (DOX)-induced cardiotoxicity. The expression pattern of nucleolin in hearts subjected toDOX injury was investigated, and we found that administration of DOX induced nucleolin expression significantly in vivo and in vitro. Gene transfection and RNA interference approaches were used in cardiomyocytes to investigate the function of nucleolin. Nucleolin overexpression protects cardiomyocytes against DOX-induced injury. Nucleolin-ablated cardiomyocytes become susceptible to the injury induced by DOX. The hearts of cardiac-myocyte-specific nucleolin transgenic mice are more resistant to DOX injury. Furthermore, nucleolin upregulates microRNA(miRNA)-21 expression in vivo and in vitro, and the miRNA-21 inhibitor negates the protective effect of nucleolin against injury induced by DOX. These results have demonstrated that nucleolin is involved in the regulation of DOX-induced cardiac injury and dysfunction via the regulation of miRNA-21 expression, and may be a novel therapeutic target for DOX-induced cardiotoxicity.

Drug-containing serum of Xinfeng capsules protect against H9C2 from death by enhancing miRNA-21 and inhibiting toll-like receptor 4/phosphorylated p-38 (p-p38)/p-p65 signaling pathway and proinflammatory cytokines expression

OBJECTIVETo investigate effect of drug-containing serum of Xinfeng capsules on myocardial cell growth. METHODSDrug-containing serum of Xinfeng capsules rat models were established by intragastricly administrated Xinfeng capsules. MTT assay was used to evaluated H9C2 cells viability. H9C2 cells were divided into normal control group, triptolide group, lipopolysaccharide (LPS) group, drug-containing serum group and miRNA-21 inhibitor group. microRNA-21 (miRNA-21) inhibitor was structured and transfected into H9C2 cells. Western blot and immunofluorescence assay were applied to examine toll-like receptor 4 (TLR4), phosphorylated p-38 (p-p38) and p-p65 expression. Quantitative real-time PCR (qRT-PCR) was used to evaluated mRNA levels of miRNA-21. Enzyme linked immunosorbent (ELISA) was used to measure tumor necrosis factor α (TNF-α), IL-6 and IL-17 levels. RESULTSDrug-containing serum treatment significantly increased cell viability compared to LPS treated group. qRT-PCR results indicated that miRNA-21 levels were significantly decreased in drug-containing serum group compared to LPS group. Early and late apoptosis in drug-containing serum group were significantly decreased compared to LPS group. Western blot and immunofluorescence assay results showed that TLR4, p-p38 and p-p65 levels in drug-containing serum group were significantly decreased compared to LPS group. ELISA findings indicated that drug-containing serum significantly decreased inflammatory cytokine levels of TNF-α, IL-6 and IL-17. CONCLUSIONDrug-containing serum of Xinfeng capsules protect against lipopolysaccharide instructed H9C2 cells from death by enhancing miRNA-21 and inhibiting TLR4/p-p38/p-p65 signaling pathway and proinflammatory cytokines expression.

Gold nanoparticle-based 2′-O-methyl modified DNA probes for breast cancerous theranostics

MicroRNAs (miRNAs) are a class of small non-coding RNAs that regulated diverse cellular processes including differentiation, proliferation, apoptosis, metabolism and signal transduction pathways. An increasing number of data suggested that miRNA-21 could be identified as diagnostic and therapeutic biomarker for breast cancer. Meanwhile, inhibiting the function of miRNA-21, resulting in cells growth inhibition and apoptotic cells death. To realize miRNA-21detection and inhibition to diagnostic and therapeutic breast cancer cells, we developed gold nanoparticle-based 2′-O-methyl modified DNA probes (AuNP-2′-OMe-DNA probes) for diagnostic and therapeutic breast cancer. Gold nanoparticles were functionalized with chemically modified miRNA-21 inhibitor to suppress the function of miRNA-21 for the therapeutic breast cancer, at the same time, fluorophore-labeled DNA molecules were hybridized with antimiRNA-21 for diagnostic breast cancer. The results showed that the 2′-O-methyl modified DNA can improve stability, increase binding affinity to target strands and enhance the therapeutic effects. The experimental results also demonstrated that antimiR-21 were efficiently introduced into the cells and knocked down miRNA-21 to inhibit its function, leading to growth inhibition and apoptotic cells death. We prospected that chemically modified miRNA-21 inhibitor based on gold nanoparticles would be as a promising diagnostic and therapeutic platform for breast cancer clinically.

Inhibition of miRNA‑21 attenuates the proliferation and metastasis of human osteosarcoma by upregulating PTEN

The present study aimed to investigate the expression of micro (mi)RNA-21 in osteosarcoma cells, and its role in inhibiting the invasion and metastasis of osteosarcoma. Human osteosarcoma MG-63 cells and osteoblast hFOB1.19 cells were used to compare the expression of miRNA-21 using reverse transcription-quantitative polymerase chain reaction analysis. A miRNA-21 mimic or inhibitor were transfected into the MG-63 cells to upregulate and downregulate the expression of miRNA-21, respectively. The present study investigated the proliferation and invasion of transfected MG-63 cells using MTT and Transwell assays. Western blot analyses were used to investigate the regulation of important proteins in the phosphatase and tensin homolog/phosphoinositide 3-kinase/RAC-α serine/threonine-protein kinase (PTEN/PI3K/AKT) signaling pathway. Compared with hFOB1.19 cells, miRNA-21 expression was significantly upregulated in the MG-63 cells (P<0.01), which lead to increased proliferation. Downregulating miRNA-21 expression reduced the proliferation of MG-63 cells compared with hFOB1.19 cells. Invasion assays and western blot analyses revealed that the overexpression of miRNA-21 significantly enhanced the invasion ability of MG-63 cells and the expression of phosphorylated (p-)AKT, while downregulation of miRNA-21 expression reduced the protein level of AKT and p-AKT. In the MG-63 cells, miRNA-21 upregulation significantly inhibited the protein level of PTEN, resulting in significantly increased AKT and PI3K protein levels (P<0.01). In conclusion, the results of the present study indicate that the expression of miRNA-21, PI3K and AKT is increased in the osteosarcoma cell line MG-63, which results in reduced expression of PTEN and increased expression of proteins in the PI3K/AKT signaling pathway, and thus increases the aggressiveness of osteosarcoma cells.

Nanoscale Zeolitic Imidazolate Framework-8 for Ratiometric Fluorescence Imaging of MicroRNA in Living Cells.

MicroRNAs (miRNAs) play important roles in cell differentiation, proliferation, and apoptosis and have been recognized as valuable biomarkers for clinical disease diagnosis. Here, we adopt for the first time zeolitic imidazolate framework-8 (ZIF-8) as a nanocarrier to efficiently deliver a nucleic acid probe to living cells and develop a novel ratiometric fluorescence strategy based on DNAzyme for miRNA-21 imaging. A Cy5-labeled 8-17 DNAzyme strand and a Cy3-labeled substrate strand containing a segment complementary to the target miRNA-21 first form a duplex probe, and fluorescence resonance energy transfer (FRET) takes place. After adsorption on the ZIF-8 surface and cellular uptake, the probe/ZIF-8 nanocomplex degrades in acidic endosome and releases duplex probes and Zn2+, and the latter can act as an effective cofactor for 8-17 DNAzyme. The intracellular miRNA-21 hybridizes with the complementary segment of the substrate strand and results in dissociation from the DNAzyme-substrate duplex probe after DNAzyme cleaves the substrate into two fragments, accompanied by the change in the FRET signal. The proposed method has been applied to image miRNA-21 expression levels in MCF-7, HeLa, and L02 cells with high contrast and reliability. The fluctuation of miRNA-21 expression level induced by miRNA-21 mimic or inhibitor can also be monitored through the obvious imaging color change. Taken together, the proposed method provides a powerful tool for cancer diagnosis and miRNA-associated biological study.

MiRNA-21 enhances chemoresistance to cisplatin in epithelial ovarian cancer by negatively regulating PTEN.

MicroRNAs (miRNAs) are small non-coding RNAs, 8-23 nucleotides in length, which regulate gene expression at the post-transcriptional level. The present study was performed to analyze the association between microRNA-21 and cisplatin resistance in epithelial ovarian cancer (EOC) SKOV3 and SKOV3/DDP cells. In this experiment, the resistance of SKOV3 and SKOV3/DDP cells to cisplatin was evaluated using the MTT assay. Reverse transcription-quantitative polymerase chain reaction analysis was used to assess miRNA-21 levels and phosphatase and tensin homolog (PTEN) mRNA levels. Western blotting was used to assess PTEN protein levels. miRNA-21 mimics or inhibitors were transfected into SKOV3 and SKOV3/DDP cells. Prior to transfection, higher expression levels of miRNA-21 were observed in SKOV3/DDP cells compared with SKOV3 cells. Following transfection with miRNA-21 mimics, SKOV3 cells demonstrated increased sensitivity to cisplatin compared with negative control cells. Following transfection with the miRNA-21 inhibitor, SKOV3/DDP cells demonstrated decreased sensitivity to cisplatin compared with negative control cells. Furthermore, PTEN mRNA expression levels in SKOV3 cells transfected with miRNA-21 mimics was significantly lower compared with negative control cells. These results suggested that miRNA-21 may regulate cisplatin resistance by negatively targeting PTEN in EOC.

Targeted suppression of miRNA-21 inhibit K562 cells growth through PTEN-PI3K/AKT signaling pathway

目的研究靶向抑制miRNA-21表达对K562细胞生物学功能的影响，观察其对PTEN-PI3K/AKT通路相关分子表达水平的影响，探讨其在白血病发病机制中的作用。方法将化学合成的miRNA-21抑制物电转染K562细胞，RT-PCR检测K562细胞miRNA-21表达变化，MTT法检测miRNA-21对K562细胞活力影响，流式细胞术分析miRNA-21对K562细胞凋亡的影响，应用Western blot技术检测K562细胞中PTEN、PI3K及p-AKT蛋白表达水平。结果转染24 h实验组miRNA-21 mRNA相对表达水平为（8.070±5.138）%，低于各对照组（P <0.05）。转染24 h实验组K562细胞凋亡率为（13.370±0.250）%，高于各对照组（P<0.01）。实验组K562细胞的增殖抑制率由转染后24 h的（8.1± 0.9）％升至60 h的（43.1±2.1）%。成功抑制miRNA-21表达后，与对照组相比，K562细胞凋亡增加（P< 0.01），细胞中PTEN蛋白表达上调（P<0.01），PI3K及p-AKT蛋白表达下调（P<0.01）。结论靶向抑制K562细胞miRNA-21可以上调PTEN表达而抑制PI3K/AKT信号通路，发挥其抑制K562细胞增殖及促进凋亡作用。

Up-Regulation of miRNA-21 Expression Promotes Migration and Proliferation of Sca-1+ Cardiac Stem Cells in Mice.

BackgroundThis study, by regulating the expression level of microRNA-21 (miRNA-21) in antigen-1+ (Sca-1+) cardiac stem cells (CSCs), examined the role of miRNA-21 in migration, proliferation, and differentiation of Sca-1+ CSCs, and explored the use of miRNA-21 in treatment of heart-related diseases in mice.Material/MethodsThe CSCs of 20 healthy 2-month-old C57BL/6 mice were collected in our study. Immunomagnetic beads were used to separate and prepare pure Sca-1+ CSCs, which were further examined by flow cytometry. The samples were assigned to 4 groups: the blank group, the miRNA-21 mimic group, the miRNA-21 inhibitor group, and the negative control (NC) group. Quantitative real-time polymerase chain reaction (qRT-PCR), Transwell chamber assay, and the methyl thiazolylte-trazolium (MTT) assay were performed. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to measure the expression levels of GATA-4, MEF2c, TNI, and β-MHC differentiation-related genes.ResultsImmunomagnetic separation results indicated that Sca-1+ CSCs accounted for more than 87.4% of CSCs. RT-PCR results also showed that the expression level of miRNA-21 of the miRNA-21 mimic group was higher than those of the other groups (all P<0.05). Compared to the NC and the blank group, the migration of Sca-1+ CSCs was more active in the miRNA-21 mimic group and less active in the miRNA-21 inhibitor group (all P<0.05). Moreover, compared to the blank group, the proliferation of Sca-1+ CSCs was enhanced in the miRNA-21 mimic group and inhibited in the miRNA-21 inhibitor group (all P<0.05). The results of RT-PCR indicated that neither miRNA-21 mimics nor miR-21 inhibitors influenced the gene expression levels of GATA-4, MEF2c, TNI, or β-MHC.ConclusionsOur study provides evidence that up-regulation of miRNA-21 can promote migration and proliferation of Sca-1+ CSCs to enhance the capacity of Sca-1+ CSCs to repair damaged myocardium, which may pave the way for therapeutic strategies directed toward restoring miRNA-21 function for heart-related diseases.

Ursolic acid induced anti-proliferation effects in rat primary vascular smooth muscle cells is associated with inhibition of microRNA-21 and subsequent PTEN/PI3K

This study focused on the anti-proliferation effects of ursolic acid (UA) in rat primary vascular smooth muscle cells (VSMCs) and investigated underlying molecular mechanism of action. Rat primary VSMCs were pretreated with UA (10, 20 or 30μM) or amino guanidine (AG, 50μM) for 12h or with PI3K inhibitor LY294002 for 30min or with Akt inhibitor MK2206 for 24h, then 10% fetal bovine serum was used to induce proliferation. CCK-8 was used to assess cell proliferation. To explore the mechanism, cells were treated with UA (10, 20 or 30μM), LY294002 or MK2206, or transient transfected to inhibit miRNA-21 (miRNA-21) or to overexpress PTEN, then quantitative real-time PCR was used to assess the mRNA levels of miRNA-21 and phosphatase and tensin homolog (PTEN) for cells treated with UA or miRNA-21 inhibitor; western blotting was used to measure the protein levels of PTEN and PI3K. UA exerted significant anti-proliferation effects in rat primary VSMCs. Furthermore, UA inhibited the expression of miRNA-21 and subsequently enhanced the expression of PTEN. PTEN was found to inhibit the expression of PI3K. In conclusion, UA exerts anti-proliferation effects in rat primary VSMCs, which is associated with the inhibition of miRNA-21 expression and modulation of PTEN/PI3K signaling pathway.