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Objective Studies show that the role of EphB 4 in the development and progression of cancer is correlated to its ligand EphrinB2.The present study was to observe the effect of the changes in EphB4 on the expression of EphrinB2 by constructing and identifying microRNA ( miRNA) interference vectors targeting the EphB4 gene in colon cancer cells . Mte hods According to the EphB4 gene sequence , 3 pairs of oligo DNA sequences of miRNA were designed .The single strand of oligo DNA was annealed to form double-strand DNA, and then connected with the plasmid pcDNA 6.2-GW/EmGFP-miRNA.The expression vector pcDNA6.2-GW/EmGFP-miR-EphB4 was linked to pDONR221 and pLenti6/V5-DEST to construct the lentiviral expression vector pLenti 6/V5-DEST-EphB4, which was cotransfected with packaging mix (pLP1, pLP2 and pLP/VSVG) into 293FT cells by lipofectamine 2000 transfec-tion to produce lentivirus , and the lentivirus titer was measured by infection of HEK 293 cells.The stable cell lines were selected and cultured.The expression levels of EphB4 and EphrinB2 were examined by qPCR. Results Three miRNA interference vectors SR-1, SR-2, and SR-3 targeting the EphB4 gene were successfully constructed , with SR-3 exhibiting the most significant interference efficien-cy.The constructed lentiviral vector pLenti 6/V5-DEST-EphB4 was successfully packaged in 293FT cells.The virus titer was 7 ×108 Caco-2 cells. Conclusion The exogenous EphB4 expression could be significantly inhibited by treatment with specific miRNA in co-lon cancer cells .The correlation of EphB4 and EphrinB2 may be effected by many factors and need further studies .
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Objective To investigate the feasibility of inhibiting Galα (1,3)-Gal expression in mouse vascular endothelial cells by lentivirus-mediated RNAi.Methods The shRNA specified to α1,3-GT mRNA was designed and synthesized in vitro and cloned into the lentivirus vector.EOMA cells were infected by recombinant lentivirus.Real-time RT-PCR was used to detect mRNA transcriptional levels of αl,3-GT as well as immunofluorescence and flow cytometry were applied to detect Galα(1,3)-Gal antigen level after gene transfection.Co-culture of infected EOMA and serum of human was done and the survival rate was measured by MTT.Results The αl,3-GT shRNA sequences were cloned into the recombinant lentivirus vector correctly and the lentivirus was produced successfully.The transfection efficiency to EOMA was 75 %.Real-time PCR revealed that the mRNA transcription of α1,3-GT was obviously inhibited by α1,3-GT shRNA recombinant lentivirus with the rate of 88 % (P＜0.05),while there were no obvious differences among control group,no shRNA lentivirus group and negative-shRNA lentivirus group (P＞ 0.05).Immunofluorescence and flow cytometry demonstrated the same results that Galα(1,3)-Gal antigen expression in EOMA transfected by α1,3-GT shRNA lentivirus was less than that of control group,no shRNA lentivirus group and negative-shRNA lentivirus group (P＜0.05),but there were no obvious differences among the later three groups (P＞0.05).After co-culture with serum of human,MTT showed the survival rate of EOMA infected by α1,3-GT shRNA lentivirus was obviously increased (P＜ 0.05).Conclusion Recombinant α2,3-GT shRNA 1entivirus is constructed successfully,which can inhibit the expression of α1,3-GT and Galα1,3-Gal in EOMA by RNAi and control hyperacute rejection in vitro.
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Objective:To construct NBS1 microRNA expressing eukaryotic recombinants,and identify biological activity of recombinants in Hela cell after transfection.Methods:According to sequence of NBS1mRNA,the NBS1 pre-microRNA was designed and synthesized,then cloned into the GFP reporter pcDNA6.2-GW/EmGFP-miR vector and transfected into Hela cell line.To detect integrity of inset fragment through colony PCR and sequencing analysis.The biological activity of recombinants through identify interference efficiency of NBS1 microRNA recombinants by way of Real-Time PCR and Western blot were determined.Results:Sequences of inset fragment in four microRNA expressing recombinants were correct.NBS1 mRNA and protein expression of four microRNA recombinants were decrease,which is the lowest in the NBS1mi-2 group.Conclusion:Four NBS1-targeting microRNA expressing recombinants all have biological activity in Hela cell line,and NBS1mi-2 recombinant has the most interference efficiency.The microRNA expressing plasmid which were successfully constructed and lay foundation for the studies on the tumor gene therapy of microrna targeting NBS1.