Bifidobacterium adolescentis as a delivery system of endostatin for cancer gene therapy: selective inhibitor of angiogenesis and hypoxic tumor growth.

In order to overcome difficulties that hampered widespread application of antiangiogenesis in cancer therapy, a highly specific delivery system may be engaged in vivo to deliver and express antiangiogenic genes. We selected a strain of Bifidobacterium adolescentis (B. adolescentis) as the delivery system to transport endostatin gene to solid tumors. B. adolescentis with endostatin gene were injected into tumor-bearing mice through the tail vein. After the mice were sacrificed, the tumor and some normal tissues of the mice were examined. B. adolescentis were only found in the tumors and no bacilli were found in other normal tissues. Also, a strong inhibition of angiogenesis had been shown to inhibit local tumor growth in the administrated group. These results suggested that B. adolescentis only germinated and proliferated in solid tumors and might be a highly specific and efficient vector for transporting anticancer genes into target tumor in cancer gene therapy.