MP45-09 CIRCULATING TUMOR CELLS (CTC) IDENTIFICATION IN BLADDER CANCER USING EPCAM (EPITHELIAL CELL ADHESION MOLECULE): COMPARISON BETWEEN MANUAL AND AUTOMATED SYSTEM OF ISOLATION AND FUTURE PROSPECTIVE

Abstract

essential role in cancer cell invasion. Analysis of gene expression profiles revealed that the expression of an intermediate filament (IF) protein, vimentin and a cytoskeletal linker protein, plectin was upregulated in the high-metastatic BCa cells compared with the lowmetastatic BCa cell line. Here we report a novel molecular mechanism of invasive bladder cancer cell extravasation using vimentin IF and plectin. METHODS: Six human BCa cell lines (RT-4, 5637, KK-47, T24, BOY and YTS-1) and primary culture of BCa cells from three genetically independent patients were used. The expression of vimentin and plectin in BCa cells was assessed by immunoblotting. The interaction between vimentin and plectin was examined by immunoprecipitation. The spatial correlation between vimentin, plectin and F-actin in BCa cells was analyzed by confocal microscopy. To evaluate the functions of invadopodia, cells were assayed for extracellular matrix (ECM) degradation, Matrigel invasion, transendothelial invasion and lung metastasis. RESULTS: In invasive BCa cells, the expression levels of vimentin and plectin were elevated and the vimentin IF-plectin-invadopodia F-actin link was formed. Disruption of this link severely impaired invadopodia formation, reducing the capacities of ECM degradation, Matrigel invasion, transendothelial invasion and metastasis. In addition, the vimentin assembly into the filaments was required for invadepodia formation. CONCLUSIONS: Our results strongly suggest that plectin anchoring invadopodia to vimentin IF scaffolds and stabilizes invadopodia, which is a critical molecular step for BCa cell invasion and extravasation for metastasis.