Antitumor effect of a novel nuclear factor-kappa B activation inhibitor in bladder cancer cells.

Nuclear factor (NF)-kappaB is a transcription factor that not only induces and controls various genes, including those of inflammatory cytokines, but also activates genes which suppress apoptosis. It has been clearly demonstrated that certain advanced human bladder cancer cells constitutively acquire the ability to activate NF-kappaB, which not only protects cancer cells from apoptotic cell death, but also upregulates the production of various cytokines that may increase the malignant potential of the disease and cause paraneoplastic syndromes. The NF-kappaB inhibitors may therefore be useful as anticancer agents. An NF-kappaB function inhibitor, a dehydroxymethyl derivative of epoxyquinomicin C (DHMEQ), has recently been designed and synthesized. The effectiveness of DHMEQ against advanced human bladder cancer cell line KU-19-19, in which NF-kappaB is constitutively activated, has been investigated. The DNA-binding activity of NF-kappaB was completely inhibited following 2-6-h exposure to 10 microg/ml of DHMEQ. Marked levels of apoptosis were observed 48 h after DHMEQ administration. These results confirmed that NF-kappaB activation maintains the viability of KU-19-19 cells, that DHMEQ inhibited constitutively activated NF-kappaB, and, consequently, apoptosis was induced. However, it was still possible that DHMEQ caused apoptotic cell death through some other mechanism which has not yet been fully investigated. The authors conclude that DHMEQ could represent a new treatment strategy against advanced bladder cancer.