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.

Targeting solid tumors with non-pathogenic obligate anaerobic bacteria.

Molecular-targeting drugs with fewer severe adverse effects are attracting great attention as the next wave of cancer treatment. There exist, however, populations of cancer cells resistant to these drugs that stem from the instability of tumor cells and/or the existence of cancer stem cells, and thus specific toxicity is required to destroy them. If such selectivity is not available, these targets may be sought out not by the cancer cell types themselves, but rather in their adjacent cancer microenvironments by means of hypoxia, low pH, and so on.