Flt3-L gene therapy enhances immunocytokine-mediated antitumor effects and induces long-term memory

• Published in: Cancer Immunology, Immunotherapy Vol. 56; no. 11; pp. 1765 - 1774
• Main Authors: Neal, Zane C, Sondel, Paul M, Bates, Mary Kay, Gillies, Stephen D, Herweijer, Hans
• Format: Journal Article
• Language: English
• Published: Germany Springer Nature B.V 01.11.2007; Springer-Verlag
• Subjects: Adjuvants, Immunologic - genetics; Adjuvants, Immunologic - metabolism; Adjuvants, Immunologic - pharmacology; Animals; Antigens; Antineoplastic Agents - pharmacology; Cancer therapies; Cell Line; Cell Proliferation - drug effects; Combined Modality Therapy; Dendritic cells; Dendritic Cells - cytology; Dendritic Cells - drug effects; Dendritic Cells - immunology; Female; Gene therapy; Genetic Therapy; Immunologic Memory; Interleukin-2 - pharmacology; Killer Cells, Natural - cytology; Killer Cells, Natural - drug effects; Killer Cells, Natural - immunology; Kinases; Ligands; Lymphocytes; Membrane Proteins - genetics; Membrane Proteins - metabolism; Membrane Proteins - pharmacology; Mice; Mice, Transgenic; Neoplasm Recurrence, Local - immunology; Neoplasm Recurrence, Local - metabolism; Neuroblastoma; Original; Proteins; Spleen - immunology; Time Factors; Tumor Escape - immunology; Tumors; United States > US
• ISSN: 0340-7004; 1432-0851
• DOI: 10.1007/s00262-007-0320-5

Therapeutic treatment with hu14.18-IL-2 immunocytokine (IC) or Flt3-L (FL) protein is initially effective at resolving established intradermal NXS2 neuroblastoma tumors in mice. However, many treated animals develop recurrent disease. We previously found that tumors recurring following natural killer (NK) mediated IC treatment show augmented MHC class I expression, while the tumors that recurred following T cell dependent Flt3-L treatment exhibited decreased MHC class I expression. We hypothesized that this divergent MHC modulation on recurrent tumors was due to therapy-specific immunoediting. We further postulated that combining IC and Flt3-L treatments might decrease the likelihood of recurrent disease by preventing MHC modulation as a mechanism for immune escape. We now report that combinatorial treatment of FL plus hu14.18-IL-2 IC provides greater antitumor benefit than treatment with either alone, suppressing development of recurrent disease. We administered FL by gene therapy using a clinically relevant approach: hydrodynamic limb vein (HLV) delivery of DNA for transgene expression by myofibers. Delivery of FL DNA by HLV injection in mice resulted in systemic expression of >10 ng/ml of FL in blood at day 3, and promoted up to a fourfold and tenfold increase in splenic NK and dendritic cells (DCs), respectively. Furthermore, the combination of FL gene therapy plus suboptimal IC treatment induced a greater expansion in the absolute number of splenic NK and DCs than achieved by individual component treatments. Mice that received combined FL gene therapy plus IC exhibited complete and durable resolution of established NXS2 tumors, and demonstrated protection from subsequent rechallenge with NXS2 tumor.