Comparison between the clonogenic, MTT, and SRB assays for determining radiosensitivity in a panel of human bladder cancer cell lines and a ureteral cell line

Using a series of human bladder cancer cell lines and an immortalised norma l ureteral cell line, radiosensitivities measured by three different method s after a single dose of X-radiation are compared. Clear differences betwee n cell survival curves obtained using the clonogenic, microtetrazoline (MTT ) and sulforhodamine B (SRB) assays are shown. The most sensitive of the as says investigated was the clonogenic assay. The MTT and SRB assays were fou nd to be relatively insensitive especially at lower radiation levels, sugge sting that these assays may not be suitable for predicting therapeutic dose schedules in vivo, but will be important for investigating radio-sensitivi ty in cell lines with very low plating efficiences. Each assay discriminate d between a range of sensitivities in the cell lines examined, and with som e minor differences, the ordering of sensitivities using the three assays w as similar. Possible explanations for the differences between results obtai ned with the three assays are discussed. (C) 1999 Wiley-Liss, Inc.