Combination of IL-12 gene therapy and CTX chemotherapy inhibits growth of primary B16(F10) melanoma tumors in mice.

We investigated suppression of murine B16(F10) melanoma tumor growth following a therapy which involved concomitant administration of cyclophosphamide and plasmid DNA bearing interleukin-12 gene. Since both therapeutic factors display antiangiogenic capabilities, we assumed that their use in blocking the formation of new blood vessels would result in augmented inhibition of tumor growth. This combined therapy regimen indeed resulted in a considerable suppression of tumor growth. We observed a statistically significant extension of treated animals' lifespan. Interestingly, the therapeutic effect was also obtained using a plasmid without an interleukin gene insert. This observation suggests that plasmid DNA, which has been widely applied for treating neoplastic tumors, contains element(s) that elicit immune response in mice.