[Study of c-myc gene transfected T-24 human bladder cancer cells]

To investigate the roll of c-myc protooncogene in human bladder cancer, c-myc gene was transfected into T-24 human bladder cancer cells and the changes of cell characteristics were studied. C-myc gene transfection was performed, using the electroporation method described previously (J.J. Urology, 80, 1989). After electroporation, c-myc gene was transfected and neo cells were cloned in a neomycin containing medium. One typical cloned cell (myc-cl3) was obtained. And this cell clone was shown to contain more than 3 extra-copies of c-myc gene by Southern blotting analysis. Morphology and growth speed of the myc-cl3 cells were not significantly different from those of original T-24 cells. However, they easily made overlapped cell-layers in the confluent growth phase. In the soft-agarose semi-solid medium, myc-cl3 cells formed about 35 times more numerous colonies than T-24 cells. Myc-cl3 cells also formed tumors on nude-mice at a significantly higher rate than T-24 cells did. These results suggest that c-myc gene plays a key roll in clonal growth and tumor formation in human bladder cancer.