Objective To use an improved technique to construct the recombinant adeno-associated virus 2 (rAAV2) mediated gene which can transfer human tissue inhibitor of metalloproteinase-1 (TIMP1). Methods Human TIMP1 gene was amplified from pDNR-LIB plasmid by PCR and cloned into the rAAV2 vector pSNAV to recombinant pSNAV-TIMP1, then was transferred into BHK-21 cells by means of lipofectamine. Using G418 selection, a mixed cell named BHK-21/rAAV2-TIMP1 was isolated, which was capable to express TIMP1. The cell was subsequently infected with recombinant herpes simplex virus 1 (rHSV1-rc/△UL2) that was able to package the rAAV2-TIMP1. After purification, rAAV2-TIMP1 was obtained. Results The rAAV2 carrying human TIMP1 gene was constructed successfully. The viral titer of the rAAV2-TIMP1 was 1×1012 v.g./ml. Conclusion rAAV2-TIMP1 was constructed successfully, which would provide experimental basis for carrying the TIMP1 into hepatocellular carcinoma effectively and inhibiting the invasiveness and migratory capacity of hepatocellular carcinoma in vitro and in vivo models.
Objective To verify the potential of the recombinant adeno-associated virus 2 (rAAV2) vector as a strategy for human transforming growth factor β1 (hTGF-β1) gene transfer in degenerative intervertebral discs of rabbit, to investigate the gene transduction efficacy and to quantify the biologic effects on the proteoglycan level after gene transferring. Methods Rabbit models of disc degeneration were established by injecting the 25 μL fibronectin fragment (Fn-f, 1 mmol/ L), 4 weeks later,saline with or without virus was injected directly into 96 lumbar discs of 24 mature New Zealand white rabbits (male or female and weighing 1.7-2.2 kg) which were divided into 3 groups (n=8). Group A received the 25 μL rAAV2-hTGF-β1 (1 × 1012 vg/mL); group B received rAAV2-enhanced green fluorescent protein (rAAV2-EGFP); and group C received PBS. Two rabbits of groups A, C were killed 1 week after injection, the immunohistochemical staining for hTGF-β1 was performed on the sl ices of nucleus pulposus (NP) tissues. At 4, 8, and 12 weeks after gene transferring, NP tissues were harvested and cultured to quantify the changes of the proteoglycan level using 35S-sulfate incorporation assay. The expression of EGFP in group B was observed 12 weeks after injection. Results Immunohistochemical staining showed that extensive and intense positive immunohisochemical staining for hTGF-β1 were seen in group A when compared with group C 1 week after gene transferring. The nucleus pulposus tissues from the group A exhibited an increased synthesis of proteoglycan, which was significantly more than that from groups B and C (P lt; 0.05), and no significant difference was observed between group B and group C. The expression of EGFP in group B was high at 12 weeks. Conclusion The discs injected with rAAV2-hTGF-β1 can highly expressed the therapeutic proteins for more than 12 weeks, it is suggested that rAAV2 should be an valid vector for transferring exogenous genes in the degenerative disc. The therapeutic factors hTGF-β1 can efficiently increase the proteoglycan synthesis of the degenerative NP cells.