[Antitumour study with combined IL-2 gene therapy and radiation for head and neck squamous cell carcinoma]

To assess the efficacy of combination therapy with IL-2 gene transfer and radiation in an immunocompetent murine model that parallel more closely the clinical therapy of head and neck Squamous cell carcinoma(HNSCC).

Tumors were established in the floor of mouth in C3H/HeJ mice with SCC VII cell line. Lipid-DNA complexed (lipoplexes) by using polycationic liposome-Mediated transduction for HNSCC were transducted in tumor-bearing mouse by direct intratumoral gene transfer. The local tumor radiation with 2 Gy were done in second day. Tumor size were measured before and after the treatment as compared to different single treatment groups and the controls. After tumors were subcultured, the supernatants were collected for IL-2 expression by enzyme-linked immunosorbent assay (ELISA). Natural killer (NK) cell activity and cytotoxic T-lymphocyte (CTL) activity were also assayed by LDH method. CD4+ and CD8+ T-lymphcyte in tumour tissues were examined by immunohistochemistry.

HNSCC tumor growth was significantly inhibited after a combined IL-2 gene and radiation therapy as compared to the controls. Increased secreted levels of IL-2 protein expression were found in combined and single IL-2 gene treated groups. The combination and IL-2 gene treated groups produced greater activation of CTL and NK than the other groups. The significant CD4+ and CD8+ T lymphocyte infiltration was distributed in tumor tissues after IL-2 gene therapy.

Combined IL-2 gene therapy and radiation could significantly inhibited HNSCC tumor growth in the murine model and efficiently induced antitumor immunity of the host.