[CNHK200-hA-a gene-viral therapeutic system and its antitumor effect on lung cancer].

OBJECTIVE: To develop a novel vector system, which combines the advantages of the gene therapy, antiangiogenic therapy and virus therapy, and to observe its effect on lung cancer. METHODS: Human angiostatin gene hA(k1-5) was inserted into the genome of the replicative virus specific for the tumor cells by virus recombination technology. The expression of hA(k1-5), its effect on tumor growth in vitro and in vivo were studied. RESULTS: A new kind of gene-viral vector system, designated as CNHK200-hA(k1-5), in which the E1b55 000 gene was deleted but the E1a gene of adenovirus preserved, was constructed. The novel vector system possessed the same property as the replicative virus ONYX-015, which replicates in p53- tumor cells but not in normal cells, thus specifically kills tumor cells. In vitro, CNHK200-hA and Ad-hA both could kill A549 tumor cells but the latter needed 100 times more MOI to achieve the same amplitude of cell killing. In vivo, the therapeutic effect of CNHK200-hA on human lung cancer A549 xenograft in nude mice was significantly better than that of Ad-hA and that of tumor-replicative virus ONYX-015. CONCLUSION: CNHK200-hA(k1-5), a novel vector is constructed in which the angiostatin gene is inserted into the genome of the replicative adenovirus cytotoxic to p53-negative tumor cells. It has the advantages of specific tumor targeting, high level gene expression in tumor cells, and potent tumoricidal activity.

[Construction and analysis of in vitro expression of adenovirus/adeno-associated hybrid virus containing the fusion gene of human beta-endorphin].

The fusion gene of human beta-endorphin was cloned into the shuttle plasmid pDC312-AAVEE with the method of molecular bilology. The latter and genomic plasmids were cotransfected into HEK293 to package the Adenovirus/Adeno-associated hybrid virus containing fusion gene of human beta-endorphin. The hybrid virus was identified with the method of PCR. The titer of proliferated virus, after purified, was determined by TCID50. The expression of transgene was studied after the hybrid virus infected the cultured cells, through testing the concentration of expressed product in the culture liquid by ELISA. It was identified that the sequence of fusion gene of human beta-endorphin was correctly inserted into the genome of hybrid virus, and not contaminated by wild type virus. The titer of Ad/AAV-EE is 1.29 x 10(10) PFU/mL after purification. The ascending trend of transgene expression was observed from the 1st to the 14th day, and the protein concentration reached 3141 pg/mL at the 14th day.

[Gene therapy for ovarian cancers by adenovirus-mediated complete antibody gene].

OBJECTIVE: To study the feasibility of adenoviral transduction of Herceptin complete antibody gene and its effect on Her2 over-expressing cancer. METHODS: The genes of VH and VL from the monoclonal antibody Herceptin were cloned into the genome of replication-defective adenovirus by viral recombination technology to produce the recombinant adenovirus Ad-SG-Her. Normal human liver cells of the line L-02 were transfected with Ad-SG-Her and ELISA was used to detect the expression of Herceptin antibody 3 and 7 days after. Forty BALB/c nude mice were inoculated with Her2 high-expressing oophoroma cells of SK-OV-3 line and were randomized into 4 equal groups: group A injected with Ad-SG-Her at the dosage of: 2 x 10(9) plaque forming unit (pfu) through the caudal vein, group B injected with Ad-SG-Her at the dosage of 1 x 10(9) pfu, group C injected with Ad-SG-Her at the dosage of 5 x 10(8) pfu, and control group. On the days 3, 7, 10, 14, 21, 28, and 35 after the injection of virus, the antibody expression in the serum was measured by ELISA and the size of tumor was measured vernier caliper. Western blot and IFA was used to detect the specificity for Her2-overexpressing ovarian cancer cell lines SK-OV-3 and the integrity of complete antibody. Anti-tumor effects were also observed in nude mice bearing SK-OV-3 tumors. RESULTS: The constructed recombinant adenovirus Ad-SG-Her could express Herceptin efficiently both in vitro and in vivo. The biological activity of the expressed antibody was similar to that of the commercial Herceptin as shown by Western blotting, IFA, and ELISA. Herceptin expression of Ad-SG-Her was detected since day 3 after treatment in the groups A, B, and C and reached the peak on days 7 - 10. The expression lasted for four weeks or so. The expression level was significantly different between group A and the groups B and C (all P < 0.05), however, without a significant difference between the group B and group C. The antibody expression of group A might increase to 103.5 micro g/ml, high enough to inhibit tumor growth and induce tumor cell apoptosis. The antibody expression of the group B was below 40 micro g/ml, and that of the group C was below 30 micro g/ml. Furthermore the expressed antibody doses were statistically significantly different at different time points. Almost no tumor growth was seen in the group A during the observation period in comparison with the groups B and C and the control group (all P < 0.05). The tumor growth was almost not influenced in the group B and C and the control group. CONCLUSION: Ad-SG-Her efficiently expresses humanized complete Herceptin with effective bioactivity and induces long-term stable expression both in vitro and in vivo. The system may serve as a new antitumoral gene therapy strategy in antibody field.

[The specific cytotoxic effect of tumor infiltrating lymphocytes transfected with chimeric T cell receptor on cells which express KDR].

OBJECTIVE: To investigate the specific cytotoxity of tumor infiltrating lymphocytes (TIL) transfected with chimeric T cell receptor (CTCR) on cells which express KDR. METHODS: A recombinant retroviral plasmid (pMSCVneo-Vhgamma) was constructed by cloning VEGF121-hinger-FcRgamma (Vhgamma) into retroviral vector pMSCVneo. After packaging by PT67, the virus with high titer was used to infect TIL isolated from liver cancer tissues, and then MSCVneo-Vhgamma-TIL was generated. TIL infected with MSCVneo was used as a control. The cytotoxicty of the transgenic TIL on NIH3T3 and HepG2 expressing no KDR and on ECV304 and A375 expressing KDR was detected with MTT colorimetric assay. RESULTS: The sequences of VEGF121 and hinger-FcRgamma were different from those reported, but the deduced amino sequences were identical to the reported ones. The cytotoxity of TIL infected with MSCVneo on target cell was similar to that of the control TIL; both only had mild cytotoxity on cancer cell line. No significant cytotoxity was found in TIL infected with MSCVneo-cTCR on NIH3T3, but its cytotoxity on ECV304 was significant. The cytotoxity on HepG2 was similar to that of MSCVneo-TIL and uninfected TIL, but cytotoxity on A375 was significantly higher. CONCLUSION: Chimeric T cell receptor permanently grafts TIL cell with predefined new specificity. TIL expressing Vhgamma can selectively recognize and kill vascular endothelial cell and tumor cells which express VEGF receptor KDR.

[In vitro gene therapy of hepatocellular carcinoma using replication-defective and tumor-specific replication-competent adenovirus carrying interleukin-12 gene].

OBJECTIVE: To evaluate the therapeutic effect and the expression level of a tumor-specific replication-competent adenovirus and a replication-defective adenovirus expression mouse recombinant IL-12 (mIL-12) gene on hepatocellular carcinoma (HCC) in vitro. METHODS: The cytotoxicity of replication-competent adenovirus with E1B-55 000 attenuated CNHK200-mIL12 and ONYX-015 (dl1520), and replication-defective adenovirus Adv-mIL12 were evaluated by MTT and replication assay in two HCC cell lines (HepG2 and Hep3B) and human normal hepatocyte line (LO2). Western blot and ELISA were used to determine the expression level of mIL-12. RESULTS: CNHK200-mIL12 replicated in HepG2 and Hep3B with an increase of 3,160-fold and 630-fold respectively in 96 h post-infection. CNHK200-mIL12 could kill HepG2 and Hep3B cells at a very low MOI (Multiplicity of Infection) and in short time course (HepG2:MOI = 0.2, on day 4; Hep3B:MOI = 0.005, on day 2), while it had no significant effect on LO2. Furthermore, the expressing level of mIL-12 in CNHK200-mIL12 treated HCC cell lines was much higher than that in Adv-mIL12 treated one (HepG2 101-fold, Hep3B 20-fold respectively). CONCLUSION: Replication-competent adenovirus is more effective than replication-defective adenovirus in both cytotoxicity and efficiency of gene transfer in HCC, and holds great promise in the area of HCC therapy.