Tumor-Targeting Therapy Using Gene-Engineered Anaerobic-Nonpathogenic Bifidobacterium longum.

Despite great progress in molecular-targeting drugs for cancer treatment, there are problems of disease recurrence due to cancer-cell resistance to those drugs, derived from the heterogeneity of tumors. On one hand, the low-oxygen microenvironment present in malignant tumor tissues has been regarded as a source of resistance of cancer cells against conventional therapie, such as radiation and chemotherapy. To overcome these problems, we have been developing a system to selectively deliver a large amount of anticancer drugs to malignant tumors by making use of the limiting factor, hypoxia, in tumors. Our strategy is to use hypoxia as a selective target. Here, we show methods and protocols using the nonpathogenic obligate anaerobic Bifidobacterium longum as a drug-delivery system (DDS) to target anaerobic tumor tissue.