Establishment and characterization of a doxorubicin-resistant human bladder cancer cell line (MGH-U1R).

A doxorubicin-resistant bladder cancer cell line has been established. This was accomplished by exposing an established human bladder tumor cell line, MGH-U1, to progressively higher concentrations of doxorubicin over a period of 12 months. The resistant cells, MGH-U1R, are nine times more resistant to doxorubicin and 30 times more resistant to daunorubicin than the parent cells. The MGH-U1R and the MGH-U1 cells have identical isozyme phenotypes. Compared to the parent cells, the resistant cells have a slower growth rate, lower confluent density, are more heterogeneous morphologically, and exhibit more chromosomal aberrations and rearrangements. The resistant cells may now be used as an experimental system for the search of means to overcome drug resistance in human bladder cancer.