Immunotherapy of Bladder Cancer Using Autologous Dendritic Cells Pulsed with Human Lymphocyte Antigen-A24-specific MAGE-3 Peptide

Recent investigations have demonstrated the efficacy of autologous dendritic cells (DCs) pulsed with tumor antigens to generate tumor-specific CTLs against cancer cells. Melanoma antigens (MAGE) are a family of tumor-specific antigens shown to be expressed in various tumors, including bladder cancers and melanoma, but not in normal tissues except for the testis. Because invasive bladder cancers are frequently reported to express MAGE, we explored the possibility of establishing a new immunotherapeutic modality against advanced bladder cancer using autologous DCs pulsed with one of the MAGE-3 epitope peptides (IMPKAGLLI), which is synthesized to bind specifically to HLA-A24. A MAGE-3-expressing bladder cancer cell line, FY, was newly established from a lymph node metastasis of bladder cancer in a HLA-A24+ patient. The FY cell-specific CTL response was significantly higher when CTL was induced by autologous DCs pulsed with IMPKAGLLI than by FY cells alone or by nonpulsed DCs in vitro . A total of four HLA-A24+ patients with advanced MAGE-3+ bladder cancers were treated with s.c. injections of autologous DCs pulsed with IMPKAGLLI every 2 weeks for a minimum of 6 and a maximum of 18 times. Three of four patients showed significant reductions in the size of lymph node metastases and/or liver metastasis. No significant untoward side effects were noted in these patients. This study indicated that, at sometime in the future, tumor-specific DC-based cancer immunotherapy may be useful as an additional treatment modality against advanced bladder cancer.