lncRNA-MALAT1 targets and downregulates miR-570-3p expression to promote proliferation of gastric cancer cells

AIM:To investigate whether long non-coding RNA MALAT1 (lncRNA-MALAT1) targets and down-regulates microRNA-570-3p (miR-570-3p) expression to further promote the proliferation of gastric cancer cells. METHODS:Gastric cancer cell line SGC7901 was cultured in vitro and divided into 3 groups:blank control, si-MALAT1 and si-MALAT1 NC. The si-MALAT1 and si-MALAT1 NC groups were transfected with MALAT1 siRNA and its negative control, respectively. The cell proliferation was evaluated by MTS assay. The expression of miR-570-3p was detected at different time points in the pure SGC7901 gastric cancer cell line, and the expression of lncRNA-MALAT1 and miR-570-3p in different groups was detected by RT-qPCR. The potential complementary binding sites of lncRNA-MALAT1 and miR-570-3p were predicted by RegRNA. The MALAT1 gene and its mutant fragment were cloned into luciferase reporter vector psiCHECK-2. Restriction enzyme analysis and sequencing were used to identify whether the recombinant plasmids carrying MALAT1 or MALAT1-Mut were successfully constructed. miR-570-3p mimic, miR-570-3p inhibitor, miR-570-3p mimic negative control and miR-570-3p inhibitor negative control were co-transfected into the 293T cells with the luciferase repor-ters containing MALAT1 or MALAT1-Mut. Dual-luciferase reporter assay was performed to detect luciferase activity in different groups in order to verify the relationship between lncRNA-MALAT1 and miR-570-3p. RESULTS:Compared with blank control group and si-MALAT1 NC group, the A₄₉₀ value in si-MALAT1 group was significantly decreased (P<0.01). The expression of miR-570-3p presented an obvious declining trend over time. The expression of lncRNA-MALAT1 in si-MALAT1 group was remarkably decreased, whereas the expression of miR-570-3p was obviously increased. The dual-luciferase reporter assay indicated that the MALAT1 reporter luciferase activity decreased significantly in miR-570-3p mimic group compared with mimic negative control (P<0.01), and the luciferase activity of MALAT1 reporter was obviously up-regulated in miR-570-3p inhibitor group compared with miR-570-3p mimic group (P<0.01). However, miR-570-3p mi-mic, miR-570-3p inhibitor, miR-570-3p mimic negative control and miR-570-3p inhibitor negative control showed no effect on the luciferase activity of MALAT1-Mut reporter. CONCLUSION:lncRNA-MALAT1 targets and down-regulates miR-570-3p expression to further promote the proliferation of gastric cancer cells.     

MicroPNA-21 promotes proliferation of rat Schwann cells following nerve injury

AIM: To investigate the molecular mechanism of microRNA-21 (miR-21) in the regulation of Schwann cell proliferation following nerve injury. METHODS: The expression of miR-2l was detected by real-time PCR. Synthetic miR-21 mimic and its control were transfected into rat Schwann cells. CCK-8 assay was performed to evaluate the influence of miR-21 on the proliferation of Schwann cells. The cell cycle distribution was determined by flow cytometry. The expression of transforming growth factor β-induced protein (TGFBI) and cyclin D1 were detected by Western blotting. RESULTS: The expression of miR-21 in model group was 7.87±0.75 and 7.75±0.80 times higher than that in sham operation group and blank group respectively. After transfected with miR-21 mimic, the expression of miR-21 in experimental group was 2.21±0.14 and 2.29±0.21 times higher than that in negative control group and blank group respectively. Moreover, the A₄₅₀ value of CCK-8 assay in experimental group at 48 h was higher than that in negative control group and blank group. The proliferation index in experimental group was higher than that in negative control group and blank group. At the same time, the expression of TGFBI obviously decreased and the cyclin D1 increased in the Schwann cells 48 h after transfection with miR-21. CONCLUSION: miR-21 promotes the proliferation activity of Schwann cells by down-regulating TGFBI expression.     

miR-509 regulates growth,invasion and migration of human hepatocellular carcinoma LM3 cells and survival of nude mice

AIM: To investigate the effect of microRNA-509 (miR-509) on the growth, invasion and migration of human hepatocellular carcinoma (HCC) LM3 cells and survival of tumor-bearing nude mice. METHODS: LM3 cells were transferred with miR-509 mimic and pcDNA Ras-related C3 botulinum toxin substrate 1 (pcRac1), and the expression of Rac1 was measured by Western blot. The relationship between miR-509 and Rac1 was determined by luciferase reporter assay. The invasion ability was determined by Transwell assay, and the migration ability was measured by wound healing assay. Xenograft model of HCC was established by subcutaneous injection with LM3 cells into nude mice. The survival rate of the mice were recorded and the protein level of Rac1 was determined by Western blot. RESULTS: miR-509 mimic inhibited the expression of Rac1 in the LM3 cells (P<0.05). pcRac1 attenuated the effect of miR-509 on Rac1. miR-509 also alleviated luciferase activity of wild Rac1 (P<0.05). Meanwhile, miR-509 mimic decreased the number of invasive LM3 cells and inhibited the migration of LM3 cells (P<0.05). In addition, over-expression of miR-509 up-regulated survival rate of model mice and decreased the protein level of Rac1 in the tumor tissue (P<0.01). CONCLUSION: miR-509 inhibits the invasion and migration of HCC cells and promotes the survival of tumor-bearing nude mice through inhibiting the expression of Rac1.     

MicroRNA-21 up-regulates expression of occludin by targeting ROCK1 in NCM460 cells

AIM: To investigate the role of microRNA-21 (miR-21) in regulation of tight junction (TJ)-associated protein occludin in human normal colon mucosal epithelial cell line NCM460, and to analyze related target genes. METHODS: Using miR-21 over-expression lentivirus, the NCM460 cells with miR-21 overexpression were established. The expression level of miR-21 was detected by qPCR. The expression of occludin was determined by Western blot. The target genes of miR-21 were predict by bioinformatic method. According to the scores and the appropriate literature search, a target gene was selected for further study. The miR-21 mimic and inhibitor were transfected into NCM460 cells, and the expression levels of miR-21 and ROCK1 were measured. Dual-luciferase reporter assay was also performed to verify ROCK1 as the target gene of miR-21. RESULTS: In miR-21-overexpressing NCM460 cells, the protein expression level of occludin was upregulated. Bioinformatics and literature analysis predicted that the target gene of miR-21 was ROCK1. The mRNA and protein levels of ROCK1 were down-regulated in the NCM460 cells transfected with miR-21 mimic. Accordingly, the mRNA and protein levels of ROCK1 were up-regulated in the NCM460 cells transfected with miR-21 inhibitor. Luciferase assay confirmed that miR-21-binding sequence was on the 3'UTR of ROCK1, indicating that ROCK1 is the target gene of miR-21. CONCLUSION: In NCM460 cells, miR-21 up-regulates the expression of occludin, which functions in the maintenance of intestinal epithelial mechanical barrier. ROCK1 is a target gene of miR-21, and is involved in the miR-21 regulation of occludin.     

Mangiferin attenuates hypoxia/reoxygenation-induced injury of human myocardial cells

AIM To investigate the effect of mangiferin on hypoxia/reoxygenation (H/R)-induced injury of human myocardial cells and its mechanism. METHODS Human myocardial AC16 cells were divided into normal group, H/R group and H/R + mangiferin (50, 100 and 200 μmol/L) treatment groups. The mRNA and protein expression levels of Kelch-like epichlorohydrin-associated protein-1 (Keap-1), Bax, Bcl-2, caspase-3, caspase-9 and superoxide dismutase 2 (SOD2) were detected by RT-qPCR and Western blot, respectively. The protein expression of nuclear factor E2-related factor 2 (Nrf-2) in nucleus was determined by Western blot. The expression of microRNA-432-3p (miR-432-3p) was detected by RT-qPCR. The generation of reactive oxygen speciess (ROS) in the cells was measured by DCFH-DA probing. The cell viability was measured by CCK-8 assay. Apoptosis was analyzed by flow cytometry. RESULTS No significant difference in the expression of miR-432-3p and Keap-1 between normal group and H/R group was observed. Compared with normal group, the nuclear translocation of Nrf-2, the ROS level, and the mRNA and protein expression of Bax, caspase-3 and caspase-9 were significantly increased in H/R group （P<0.05）. The mRNA and protein expression of SOD2 and Bcl-2, and the cell viability significantly decreased in H/R group compared with normal group, while the apoptosis was increased significantly （P<0.05）. Treatment with mangiferin resulted in an increase in the miR-432-3p expression and a decrease in the ROS level, and the expression of Keap-1, Bax, caspase-3 and caspase-9 was also inhibited as compared with H/R group （P<0.05）. The Nrf-2 nuclear translocation, and the protein levels of SOD2 and Bcl-2 in mangiferin treatment groups were significantly increased as compared with H/R group （P<0.05）. The cell viability was increased significantly, and the apoptosis was decreased significantly in mangiferin treatment groups as compared with H/R group （P<0.05）. The effects of mangiferin in middle- and high-dose groups were better than those in low-dose group, and no significant difference between middle- and high-dose groups was found. CONCLUSION Mangiferin inhibits the decrease in myocardial cell viability and the apoptosis induced by H/R injury. The mechanism may be related to the up-regulation of Nrf-2 antioxidant stress effect via enhancing the expression of miR-432-3p.     

Mechanism of microRNA-138-5p inhibiting proliferation,migration and invasion of lung cancer cells

AIM: To investigate the mechanism of microRNA-138-5p (miR-138-5p) inhibiting the proliferation, migration and invasion abilities of lung cancer cells.METHODS: The lung cancer A549 and H460 cells were transfected with miR-NC (control group) or miR-138-5p (experimental group). The bioinformatic analysis was performed to predict the target genes of miR-138-5p.The expression levels of miR-138-5p, forkhead box protein C1 (FOXC1) mRNA and vimentin mRNA were detected by RT-qPCR. The protein expression of FOXC1, vimentin, E-cadherin, N-cadherin and β-catenin was determined by Western blot. MTS method and colony formation assay were used to detect cell viability and proliferation ability. Wound healing assay and Transwell assay were used to detect cell migration and invasion ability.RESULTS: Over-expression of miR-138-5p significantly reduced the expression of FOXC1 and vimentin at mRNA and protein levels (P<0.05). The expression of E-cadherin and β-catenin were up-regulated and the expression of N-cadherin was down-regulated. The proliferation, migration and invasion abilities of the lung cancer cells were inhibited by the over-expression of miR-138-5p.CONCLUSION: miR-138-5p inhibits the proliferation, migration and invasion abilities of lung cancer cells by targeting FOXC1 and vimentin. It may be a potential target for lung cancer gene therapy.     

miR-17 regulates senescence of rat vascular smooth muscle cells

AIM: To investigate the effect of microRNA-17 (miR-17) on the senescence of vascular smooth muscle cells (VSMCs) and the underlying mechanism.METHODS: The medial layer of the thoracic aorta was collected from the SD rats and isolated for primary culture. VSMCs were identified by immunofluorescence staining. The VSMCs were collected at the 4th~6th generations, and then the miR-17 mimics and miR-17 inhibitor were transfected into the VSMCs by liposome method. After 24 h, the cell senescence was induced by D-galactose. The VSMCs were divided into the following 6 groups:aging induction+miR-17 mimics (A-miR-17) group, aging induction+miR-17 inhibitor (A-anti-miR-17) group, A-control group, normal (N)+miR-17-mimics (N-miR-17) group, N-anti-miR-17 group, and N-control group. On day 3 after the addition of D-galactose, the senescence of VSMCs was observed with β-galactosidase staining. The expression of miR-17, p16 and p21 was detected by RT-qPCR and immunohistochemistry. RESULTS: miR-17 expression in the VSMCs was significantly lower in A-control group than that in N-control group (P<0.01). Compared with A-control group, the expression of miR-17 in the VSMCs was significantly increased in A-miR-17 group (P<0.01), while that was significantly decreased in A-anti-miR-17 group (P<0.01). The number of β-galactosidase positive staining cells in A-anti-miR-17 group was significantly higher than that in A-miR-17 group (P<0.01). The expression of p21 at mRNA and protein levels in the VSMCs was significantly lower in A-miR-17 group than that in A-control group (P<0.01), and the expressions of p21 at mRNA and protein levels was significantly higher in A-anti-miR-17 group than that in A-miR-17 group (P<0.01). CONCLUSION: miR-17 inhibits rat VSMCs senescence induced by D-galactose, the underlying mechanism is associated with the inhibition of p21 expression.     

Baicalin inhibits high glucose-induced apoptosis of mouse glomerular mesangial cells via miR-141/Sirt1 signaling pathway

AIM:To investigate the therapeutic mechanism of baicalin for diabetic nephropathy involving microRNA-141 (miR-141)/silent information regulator 1 (Sirt1) signaling pathway. METHODS:Mouse glomerular mesan-gial cell line SV40-MES-13 was treated with high glucose (HG, 25 mmol/L glucose) to establish diabetic nephropathy cell model. Baicalin at 100 μmol/L was used to treat glomerular mesangial cells. qPCR and Western blot were performed to determine the expression levels of miR-141 and Sirt1. The regulatory relationship between miR-141 and Sirt1 was detected by dual-luciferase assay. The apoptosis of glomerular mesangial cells was analyzed by flow cytometry. RESULTS:Compared with control group, the cells treated with HG showed increased levels of miR-141 and apoptosis, and Sirt1 expression was decreased (P<0.01). Baicalin and miR-141 inhibitor suppressed the HG-induced effect on the levels of miR-141, Sirt1 and apoptosis. Knockdown of Sirt1 expression reversed the effect of miR-141 inhibitor on the levels of miR-141, Sirt1 and apoptosis. Over-expression of miR-141 reversed the effect of baicalin on the glomerular mesangial cells treated with HG. Up-regulation of Sirt1 abolished the effect of miR-141 over-expression on the glomerular mesangial cells. CONCLUSION:Baicalin inhibits the apoptosis of mouse glomerular mesangial cells via miR-141/Sirt1 signaling pathway, thus attenuating diabetic nephropathy.