Inhibition of Late and Early Phases of Cancer Metastasis by NF-κB Inhibitor DHMEQ Derived from Microbial Bioactive Metabolite Epoxyquinomicin: A Review

We previously designed and synthesized dehydroxyepoxyquinomicin (DHMEQ) as an inhibitor of NF-κB based on the structure of microbial secondary metabolite epoxyquinomicin C. DHMEQ showed anti-inflammatory and anticancer activity in various in vivo disease models without toxicity. Cell detachment from the primary tumor and subsequent invasion are considered to be early phase of metastasis, while tumor cell attachment to the tissue and secondary tumor formation the late phase. The assay system for late phase was set up with intra-portal-vein injection of pancreatic cancer cells. Administration of DHMEQ was found to inhibit the liver metastasis possibly by decreasing the expression of MMP-9 and IL-8. Also when the pancreatic cancer cells treated with DHMEQ was inoculated into the peritoneal cavity of mice, the metastatic foci formation was inhibited. These results indicate that DHMEQ is likely to inhibit the late phase of metastasis. Meanwhile, we have recently employed three-dimensional (3D) culture of breast cancer cells for the model of early phase metastasis. DHMEQ inhibited the 3D invasion of breast cancer cells without toxicity. In this way, DHMEQ was shown to inhibit the late and early phases of metastasis. Thus, DHMEQ is likely to be useful for the suppression of cancer metastasis.