The use of miR122 and its target sequence in adeno-associated virus-mediated trichosanthin gene therapy / 中西医结合学报

OBJECTIVE@#Plant-derived cytotoxic transgene expression, such as trichosanthin (tcs), regulated by recombinant adeno-associated virus (rAAV) vector is a promising cancer gene therapy. However, the cytotoxic transgene can hamper the vector production in the rAAV producer cell line, human embryonic kidney (HEK293) cells. Here, we explored microRNA-122 (miR122) and its target sequence to limit the expression of the cytotoxic gene in the rAAV producer cells.@*METHODS@#A miR122 target (122T) sequence was incorporated into the 3' untranslated region of the tcs cDNA sequence. The firefly luciferase (fluc) transgene was used as an appropriate control. Cell line HEK293-mir122 was generated by the lentiviral vector-mediated genome integration of the mir122 gene in parental HEK293 cells. The effects of miR122 overexpression on cell growth, transgene expression, and rAAV production were determined.@*RESULTS@#The presence of 122T sequence significantly reduced transgene expression in the miR122-enriched Huh7 cell line (in vitro), fresh human hepatocytes (ex vivo), and mouse liver (in vivo). Also, the normal liver physiology was unaffected by delivery of 122T sequence by rAAV vectors. Compared with the parental cells, the miR122-overexpressing HEK293-mir122 cell line showed similar cell growth rate and expression of transgene without 122T, as well as the ability to produce liver-targeting rAAV vectors. Fascinatingly, the yield of rAAV vectors carrying the tcs-122T gene was increased by 77.7-fold in HEK293-mir122 cells. Moreover, the tcs-122T-containing rAAV vectors significantly reduced the proliferation of hepatocellular carcinoma cells without affecting the normal liver cells.@*CONCLUSION@#HEK293-mir122 cells along with the 122T sequence provide a potential tool to attenuate the cytotoxic transgene expression, such as tcs, during rAAV vector production.

Inhibition effect of anti-epidermal growth factor receptor antibody mediated by recombinant adeno-associated virus vector on pancreatic cancer cell lines / 中华消化外科杂志

Objective To construct a recombinant adeno-associated virus(rAAV)vector containing a human anti-epidermal growth factor receptor(anti-EGFR)single-chain variable fragment antibody gene,and observe its inhibitory effects on pancreatic cancer cell lines.Methods Human anti-EGFR single-chain variable fragment antibody gene was inserted into the Kpn I and Bgl Ⅱ sites to construct a rAAV-anti EGFR vector,and then rAAV1-EGFP group and rAAV1-anti EGFR group were established.The expression of anti-EGFR antibody was observed.Antibody expression was detected by Western blot,and the inhibition and apoptosis rates of human pancreatic cancer cell lines(PCT-3,SW1990,Capan-1,ASPC-1,MiaPaCa-2 and PANC-1 cells)were detected by CCK-8 assay and flow cytometry,respectively.All data were analyzed using the t test.Results The results of Western blot assay demonstrated that anti-EGFR antibody was expressed in 6 pancreatic cancer cell lines.The inhibition rates of rAAV1-EGFP and rAAVl-anti EGFR on pancreatic ASPC-1 cells were 1.1%± 2.4% and 15.1%±3.5%,respectively,with a significant difference between the 2 groups(t =6.598,P ＜0.05).The apoptosis rates of PANC-1 cells were 7.0% ± 3.0% in the rAAV1-EGFP group and 1 1.4% ± 2.5% in the rAAV1-anti EGFR group,with no significant difference between the 2 grouvs(t = 1.952,P ＞0.05).The apoptosis rates of SW1990,ASPC-1,Capan-1,PCT-3,MiaPaCa-2 cells were 1.1% ± 0.8%,1.5% ± 0.7%,1.7% ± 1.2%,1.1%±0.7% and 2.2% ± 1.1% in the rAAV1-EGFP group,and 17.6% ± 2.2%,46.9% ± 3.9%,20.0% ±2.8%,12.1% ± 1.6% and 31.1% ±2.5% in the rAAV1-anti EGFR group,respectively,with significant differences between the 2 groups(t = 12.208,19.846,10.405,10.909,18.327,P ＜0.05).Conclusions A rAAV-anti EGFR vector with human anti-EGFR single-chain variable fragment antibody gene was constructed.Anti-EGFR antibody has obvious inhibition effects on pancreatic cancer cell lines.

Recombinant-adeno-associated viral vector-mediated gene therapy for cardiovascular diseases / 中南大学学报(医学版)

Adeno-associated virus is a kind of DNA defective parvovirus which is non-pathogenic. Recombinant-adeno-associated virus vector comes from wild-type non-pathogenic adeno-associated virus and is highly secure, and it also has the advantages of broad host range. Recombinant-adeno-associated virus vector has become a hot spot for gene therapy and is widely used in gene therapy for cardiovascular diseases, especially for hypertension, heart failure, arteriosclerosis, and myocardial infarction.

Construction and function of the recombinant vector expressing human glutamic acid decarboxylase 65 / 解剖学报

Objective To construct the recombinant rAAV2-hGAD65 vector and detect its function both in vitro and in vivo. Methods The cDNA of human glutamic acid decarboxylase 2 (hGAD65) gene, which was one of gamma-aminobutyric acid (GABA) synthetase, cloned by the method of RT-PCR, was subcloned into the adeno-associated virus (AAV) vector and formed the recombinant vector of AAV-hGAD65 (rAAV2-hGAD65). The recombinant vector was packaged by the AAV Helper-Free System and its titer was detected. The primary fibroblast, cultured from the rat lung, was transfected by the rAAV2-hGAD65. The expression of the hGAD65 in fibroblast was detected by immunohistochemical method and the level of GABA in the media was assayed by high performance liquid chromatograph (HPLC). In vivo, the hGAD65 was detected by immunohistochemical method in STN and the concentration of the GABA in the reticular part of substantia nigra (SNr) was assayed by HPLC after the rAAV2-hGAD65 was injected into the subthalamic nucleus (STN) by the stereotaxic method. Results The sequence of hGAD65 cDNA was in accordance with that in the Genebank. The amino acid sequence of hGAD65 had no mutation and the titer of rAAV2-hGAD65 was reached 4.5 ×10~(11) per milliliter. The efficiency of infection to the rat primary firoblasts was 80%, and the concentration of GABA in the media of fibroblasts was (45.66±6.07)nmol/L per liter. In vivo, hGAD65 could be detected in STN, and the concentrateion of the GABA in the SNr was increased from (5.66±1.07)nmol/g to (12.66±2.59)nmol/g.Conclusion The cDNA of hGAD65 was cloned by RT-PCR and the recombinant vector of rAAV2-hGAD65 was constructed. The AAV can infect the primary fibroblast in vitro and the hGAD65 can catalyse the glutamic acic to GABA. In vivo, the concentration of GABA in the SNr was heighten after the rAAV2-hGAD65 was injected into the STN.

Methodology of transfecting gene into liver graft mediated by adeno-associated virus vector / 中华消化外科杂志

Objective To investigate the effective route and proper method in transfecting gene into liver graft mediated by adeno-associated virus vector.Methods Three routes including hepatic artery,portal vein and hepatic artery+portal vein,and 3 methods,i.e.routine,circulation and clamping were employed for infusion.The best infusion route and method of gene transfection into liver graft were determined by observing the color change of liver and detecting liver function and transfoetion rate of liver cells.The safety of these methods was evaluated.Results In all the infusion procedures,the color of the liver grafts turned from red to white,no apparent color differenee of the livers and no enlargement nor mottling were observed under surgical microscope.The liver color was back to normal immediately after blood flow was restored.No significantly statistical differences of the ALT values were observed among all the groups(F=0.343,1.265,0.055,P＞0.05).Adeno-associated virus vectors coding for the enhanced green fluorescence protein(AAV2-EGFP)were successfully transfected into liver cells by the 3 infusion routes 1 week later,and the difierences of transfection rates via the 3 routes had no statistical significance(F=0.080,0.091,0.045,P＞0.05).The transfoction rate of AAV2-EGFP was the highest at any time points when using the clamping method,and then followed by circulation method and routine method,with statistical differenee(F=3.880,2.976,5.129,P＜0.05).The transfection rates of AAV2-EGFP were increased progressively and peaked at the 6th week,and then they were decreased gradually.Conclusions Infusion via hepatic artery is the effective route for gene transfection and clamping the vessels can elevate the transfection rate of AAV2-EGFP.All procedures were performed without detectable liver injury.The transfection of gene into liver graft mediated by adeno-associated virus vector is a slow and persistent process.