TLR4 Signaling Induces B7-H1 Expression Through MAPK Pathways in Bladder Cancer Cells

Abstract

TLR4 (Toll-like receptor 4) and B7-H1, which were known to be restricted to immune cells in the past, were found to be aberrantly expressed in a majority of tumor cells, facilitating tumor evasion from immune surveillance. Our study demonstrated that activation of TLR4 signaling in bladder cancer cells up-regulated B7-H1 expression. Furthermore, this regulation was significantly attenuated by ERK or JNK inhibitor. Our results elucidated the molecule mechanism of regulation of B7-H1 expression through TLR4 signaling and may suggest new strategies of down-regulating the cancer-associated B7-H1 expression for bladder cancer treatment.