Cancer - Bladder, Pelvis, Ureter & Others(구연) Oral Session 4 / Cancer - Bladder, Pelvis, Ureter & Others (Ⅰ) (O-038) Geumkang Hall (Avenue 2F) 11월28일(수) 13:00-14:00 Suppression of CD81 promotes bladder cancer cell invasion through increased matrix metalloproteinase expression via Erk phosphorylation. 을지대학교 의과대학 비뇨의학과교실 을지대학교 의과대학 미생물학교실 박현식1, 이수혁2, 유승민2, 이명신2, 박진성1 Introduction and Objective: We found novel prognostic biomarker, CD81, in high grade bladder cancer (BC) using antibody microarray in our prior study (PLoS One. 2015). In this study, we aimed to reveal the functional mechanisms underlying the role of CD81 in BC carcinogenesis. Materials and Methods: CD81 expression was suppressed in two invasive BC cell lines (T24, J82) by transfection with lentiviral vectors including CD81-specific shRNAs. CD81 expression was analyzed by Western blotting and flow cytometry. Transwell migration and invasion assays were conducted using BD Falcon cell culture inserts with Matrigel-coated or non-coated membrane. The expression of matrix metalloproteinases (MMPs) was analyzed by RT-qPCR with extracted RNA and Western blotting with the concentrated conditioned media, respectively. Enzymatic activity of MMPs was also analyzed by collagen-zymography. Signaling pathways related to MMPs were investigated by applying various chemical inhibitors. Results: CD81 was successfully knocked down by shRNAs in T24 and J82 cell lines. While migration of BC cell was not affected after knockdown of CD81, invasive activity was significantly increased in both cell lines (Fig 1A and 1B). Obvious bands were observed in zymography with supernatants from CD81-knockdown cells, whereas only faint bands were observed with empty vector-transfected cells. We also observed the increased expression of MMPs, specifically MMP 2 and 9, in the conditioned media from CD81-knockdown cells by Western blotting. Mechanistically, phosphorylation of Erk was associated with the invasive activity of BC cells, while U0126 (Erk inhibitor) reduced invasive activity of CD81-knockdown BC cells (Fig 1C). Conclusion: Taken together, CD81 suppression promotes invasive property of BC cells through MMP signaling pathway via Erk phosphorylation. Our results suggest therapeutic potential of CD81 regulation in BC. keywords : Bladder cancer, CD81, matrix metalloproteinase