GELSOLIN - A CANDIDATE FOR SUPPRESSOR OF HUMAN BLADDER-CANCER

Human transitional cell carcinomas of the bladder frequently reveal ch romosomal abnormalities that span a range between chromosome 9p12 and 9qter, even at early stages of bladder carcinogenesis. Because the gen e that encodes an actin-regulatory protein, gelsolin, is localized in chromosome 9q33, we examined the expression of gelsolin in a number of human bladder cancer cell Lines and tissues. In all 6 cell lines and in 14 of the 18 tumor tissues (77.8%), gelsolin expression was undetec table or extremely low in comparison with its expression in normal bla dder epithelial cells. Furthermore, upon the introduction of the exoge nous human or mouse authentic gelsolin cDNA into a human bladder cance r cell line, UMUC-2, gelsolin transfectants of UMUC-2 greatly reduced the colony-forming ability and the tumorigenicity in vivo. These resul ts suggest that gelsolin plays a key role as a tumor suppressor in hum an urinary bladder carcinogenesis.