MP49-09 ACTIVATION OF IFN/STAT1 SIGNALING IN CISPLATIN/GEMCITABINE RESISTANT BLADDER CANCER

migratoryand invasiveproperties tobecomemesenchymal stemcells.EMT has been implicated in the initiation of metastasis for cancer progression. METHODS: Exosomes were isolated by ultracentrifugation from T24 or UMUC3 invasive bladder cancer cell conditioned media. T24 exosomes were added to urothelial cells for 4, 6, 24 or 48 hours. RNA or protein was collected from the urothelial cells and qRT-PCR or western blotting was performed to measure expression of EMT markers. T24or UMUC3-derived exosomes were added to urothelial cells and plated in transwell inserts for migration and invasion assays. RESULTS: Urothelial cells treated with T24 or UMUC3 bladder cancer exosomes showed an increased expression in several mesenchymal markers, including a-SMA, S100A4, and Snail, as compared to PBS treated cells. Moreover, treatment of urothelial cells with T24or UMUC3-derived exosomes resulted in decreased expression of epithelial markers, including e-cadherin and b-catenin, as compared to the control, PBS treated cells. T24and UMUC3-derived exosomes also increased the migration and invasion of urothelial cells, and this was blocked by heparin pre-treatment. We further showed that exosomes isolated from patient urine and barbotage samples were able to induce the expression of several mesenchymal markers in recipient urothelial cells. CONCLUSIONS: In thisstudy,weestablished thatexosomes from invasive bladder cancer cells are able to induce EMT in recipient urothelial cells. We further showed that exosomes from invasive bladder cancer cells can promote migration and invasion of recipient urothelial cells. We also demonstrated that the effect on migration and invasion is mediated by heparin. Finally, we established that exosomes isolated from bladder cancer patients hada similar effect on the expression ofmesenchymalmarkers in urothelial cells as the exosomes isolated from bladder cancer cell lines.