Regression of tumors by IFN-α electroporation gene therapy and analysis of the responsible genes by cDNA array

The key to success with nonviral gene therapy as a treatment for cancer is to discover effective therapeutic genes and gene delivery methods and to understand how tumors are eradicated. We discovered that electroporation of IFN-alpha DNA into tumors in the SCCVII tumor-bearing mice led to tumor eradication in 50% of the mice and a more than twofold increase in survival time when compared with controls (P = 0.0012). Analyses using cDNA array and Northern blot indicated that the genes responsible for the therapeutic effect of electro-IFN-alpha gene therapy included IRF-7, Granzyme A, Granzyme C, Gjb2, Krt14, Mig, IP-10 and MCP3. Because most of these genes have been known to either inhibit angiogenesis (Mig, IP-10), inhibit tumor growth (Gjb2, MCP3), kill tumor cells (Granzyme A and C), or induce expression of antitumor gene (IRF-7), they may become promising therapeutic gene candidates for a combination gene therapy approach to cancer treatment.