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The transcriptional factor Oct-4 and Survivin are the key regulatory factors in cancer cell proliferation and mitosis. A dual cancer-specific shRNA adenovirus vector, Ad5-Dual-shRNA, targeting Oct-4 and Survivin genes was constructed by molecular cloning and recombination. After cells were infected with virus, hepatocellular carcinoma cell line EHBH-H1 was used for detecting the expression of Oct-4 and Survivin proteins by Western blotting. The viral cytotoxic effect on cancer cells was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction assay in vitro, and the inhibition effect on tumor xenografts was observed in nude mice. The results showed that the expression of Oct-4 and Survivin in cancer cell line EHBH-H1 could be silenced markedly by Ad5-Dual-shRNA. In MTT and animal experiments, Ad5-Dual-shRNA also represented much stronger anti-tumor effect on tumor growth than Ad5-Surv-shRNA and Ad5-Oct4-shRNA. From this research we can draw a conclusion that the cancer-specific adenovirus vector expressing dual-shRNA targeting Oct-4 and Survivin genes may provide us a more effective, specific and convenient gene therapy method.

The regulation of a target gene expression is very important in gene therapy. However, constitutive or inappropriate expression of the genes with traditional expression system may interfere with the effect of the gene therapy, even may lead to lethal side effect. We constructed an RU486 inducible eukaryotic vector carrying DsRed protein and evaluated its regulatable effect in vitro. The single vector named PDC-RURED was constructed with molecular biological methods, which contained DsRed gene, promoter and RU486-inducible system. To minimize any potential interference, we spaced the two transcriptional elements with a 1.6 kb insulator. The vector was identified by different enzyme restrictions, sequencing analysis and PCR assay. We demonstrated the regulatable expression of this vector after transfection in HEK293 cells by fluorescence microscopy and flow cytometry. In the absence of RU486, no significant DsRed protein activation was observed, whereas in the presence of RU486 up to 40 fold activation of the DsRed protein was observed in cultured cells. The data show that the novel eukaryotic expression plasmid vector can be used to regulate the expression level of genes of interest in appropriate time under the control of RU486. This inducible expression vector provides a powerful tool for the research of gene regulation and gene therapy.

Objective: To study the status of CDKN2/p16 gene point mutation in lung cancer., Methods: Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and sequencing were used to detect the point mutation of CDKN2/p16 gene exon 2 in 89 cases of lung cancer., Results: In 69 cases of the lung cancer without deletion of CDKN2/p16 gene exon 2, 16 cases were found to have suspicious abnormality of CDKN2/p16 gene exon 2 by PCR-SSCP, and in these 16 cases, 9 were found to harbor point mutations of CDKN2/p16 gene exon 2 by automated sequencing analysis., Conclusion: The point mutation is one of the mechanisms for CDKN2/p16 gene inactivation, but it is not the chief mechanism. The inactivation of CDKN2/p16 gene aroused by point mutation plays a role to some extent in the genesis and progression of lung cancer.