ABSTRACT
OBJECTIVE: To determine the feasibility and efficacy of combination nonviral lipid-formulated murine interleukin 2 (mIL-2) and polymer-formulated murine interleukin 12 (mIL-12) gene therapy for head and neck squamous cell carcinoma (HNSCC) in a murine model. METHODS: Randomized, controlled studies in a murine HNSCC model. Tumors were established in the floor of mouth in C3H/HeJ immunocompetent mice. Established tumors were directly injected with lipid-formulated mIL-2 and polymer-formulated mIL-12 alone and in combination. Antitumor responses, cytokine expression, and natural killer cell and cytolytic T-lymphocyte activity were assayed. RESULTS: The use of combined mIL-2 and mIL-12 gene therapy resulted in significant antitumor effects, compared with each of the single-cytokine and no-treatment (control) groups (P =.01 to P =.02). Tumors treated with the formulated cytokine genes showed an increased level of the corresponding proteins and decreased level of transforming growth factor beta (TGF-beta) expression. Combined mIL-2 and mIL-12 treatment consistently produced the greater activation of cytolytic T-lymphocyte and natural killer cells than did single-cytokine treatment or other controls at all concentrations tested. Augmented immune responses correlated with clinical antitumor effects. CONCLUSIONS: The nonviral gene delivery system was well tolerated, and combined mIL-2 and mIL-12 gene transfer generated potent antitumor immune responses against HNSCC in our murine model. Combined nonviral IL-2 and IL-12 gene therapy may have great potential as a primary or adjuvant treatment for HNSCC in humans.