Recombinant BCG therapy suppresses melanoma tumor growth.

Abstract

Melanoma is the fastest rising cancer in the United States. Bacillus Calmette-Guerin (BCG) has been genetically engineered to actively express and secrete the cytokine interleukin-2 (IL-2). Both BCG and IL-2 have known potent antitumor and immunomodulatory properties. This recombinant BCG (rBCG 3A) has been tested as an intratumoral injection and a vaccine therapy in conjunction with irradiated tumor cells against melanoma in the murine B16 melanoma model. The transfection process did not adversely alter the function of the wild-type (WT) BCG. rBCG 3A and WT BCG are equally effective intratumoral and vaccine therapies against melanoma when compared with normal saline control groups. Tumor burdens were significantly smaller (p < or = 0.01 and 0.05) for the treatment groups for both intratumoral and vaccine administration of therapy. Immunization with rBCG 3A and WT BCG 14 days before a B16 challenge resulted in an approximately 45% smaller tumor burden when compared with controls. Novel therapies based on the immunogenic properties of melanoma combined with molecular technologies may offer promise for an effective and safe treatment of melanoma.