Enhanced Growth inhibition by Combined Gene Transfer of p53 and p16INK4a in Adenoviral Vectors to Lung Cancer Cell Lines / 결핵

BACKGROUND: Two tumor suppressor genes, p53 and p16, which have different roles in controlling the cell cycle and inducing apoptosis, are frequently inactivated during carcinogenesis including lung cancer. Single tumor suppressor gene therapies using tither with p53 or p16 have been studied extensively. However, there is a paucity of reports regarding a combined gene therapy using these two genes. METHODS: The combined effect of p53 and p16 gene transfer by the adenoviral vector on the growth of lung cancer cell lines and its interactive mechanism was investigated. RESULTS: An isobologram showed that the co-transduction of p53 and p16 exhibited a synergistic growth inhibitory effect on NCI H358 and an additive effect on NCI H23. Cell cycle analysis demonstrated the induction of a synergistic G1/S arrest by a combined p53 and p16 transfer. This synergistic interaction was again confirmed in a soft agar clonogenic assay. CONCLUSION: These observations suggest the potential of a p53 and p16 combination gene therapy as another potent strategy in cancer gene therapy.

The Effect of IkappaBalpha-SR Gene Transfer on the Sensitivity of Human Lung Cancer Cell Lines to Cisplation and Paclitaxel / 결핵

BACKGROUND: Some chemotherapeutic drugs induce NF-κB activation by degrading the IκBα protein in cancer cells which contributes to anticancer drug resistance. We hypothesized that inhibiting IκBα degradation would block NF-κB activation and result in increased tumor cell mortality in response to chemotherapy. METHODS: The "superrepressor" form of the NF-κB inhibitor was transferred by an adenoviral vector (Ad-IκBα-SR) to the human lung cancer cell lines (NCI H157 and NCI H460). With a MTT assay, the level of sensitization to cisplatin and paclitaxel were measured. To confirm the mechanism, an EMSA and Annexin V assay were performed. RESULTS: EMSA showed that IκBα-SR effectively blocked the NF-κB activation induced by cisplatin. Transduction with Ad-IκBα-SR resulted in an increased sensitivity of the lung cancer cell lines to cisplatin and paclitaxel by a factor of 2~3 in terms of IC50. Annexin-V analysis suggests that this increment in chemosensitivity to cisplatin probably occurs through the induction of apoptosis. CONCLUSION: The blockade of chemotherapeutics induced NF-κB activation by inducing Ad-IκBα-SR, increased apoptosis and increasing the chemosensitivity of the lung cancer cell lines tested, subsequently. Gene transfer of IκBα-SR appears to be a new therapeutic strategy of chemosensitization in lung cancer.

Combination Gene Therapy of Herpes Simplex Virus Thymidine Kinase and Cytokines in Lung Cancer / 결핵

BACKGROUND: One of the important mechanisms responsible for a tumor escaping the immune response is an absence of the tumor associated antigen (TAA) on the cancer cell surface. To overcome this, combination gene therapy using a herpes simplex thymidine kinase (HSTK) gene, prototype of drug sensitizing gene, was conducted to enhance TAA release by cell destruction, as well as the cytokine genes for immune cell attraction. METHODS: We investigated whether or not transduction with the adenovirus-HSTK (Ad-HSTK) enhanced the sensitivity of Lewis lung carcinoma (LLC) to ganciclovir (GCV) and induced a bystander effect. A Tumor vaccine trial was performed using LLC with ad-HSTK ±ad-GM-CSF±ad-IL-2 to determine if they exhibit some antitumor effect on established lung cancer xenografts. RESULTS: LLC with ad-HSTK revealed a much higher sensitivity to ganciclovir (GCV). LLC transduced with ad-HSTK and/or ad-IL-2, ad-GM-CSF showed a lower in vivo tumorigenicity. In the treatment experiment, vaccination with LLC transduced with ad-HSTK, ad-IL-2, or ad-GM-CSF alone modestly suppressed the growth of an established tumor. Combined transduction with HSTK and GM-CSF induced stronger growth suppression of a established lung cancer, while HSTK and IL-2 combination transduction did not have any antitumor effect on individual transduction. Vaccination with LLC-HSTK-GM-CSF increased the infiltration of dendritic cells in the spleen. CONCLUSION: It was concluded that a tumor vaccine transduced with HSTK and GM-CSF induces strong antitumor immunity by activating the dendritic cells.