[Sensitivity test of anti-tumor agents. 2. Application of MTT assay]

Mosmann's method for measuring the number of viable cells, examination of their growth and function by tetrazolium test, "MTT assay", is widely thought to be reliable. For the purpose to establish a rapid, accurate, in vitro drug sensitivity test, MTT assay was applied and evaluated for clinical application. Based on Mosmann's original MTT assay, optimal and adequate conditions for (1) the number of the cells examined at the starting of cultivation, (2) concentration of anti-tumor agents, doxorubicin, cisplatin, mitomycin C, L-phenylalanine mustard, (3) incubation time with anti-tumor agents, were determined using established cell lines, T-24, RMUG, HeLa, Vero, P 388, and Colon 26 in 96 well microplates. Conclusions are as below: (1) Number of the cells in each well of microplate is 1 x 10(3)-1 x 10(6) cells/ml, that seemed to be theoretically and technically adequate. (2) Anti-tumor agents should be added at the peak plasma concentration. (3) Incubation for 4 to 5 days is preferable. (4) HCl-isopropanol seemed to be advantageous compared to 10% sodium dodecyl sulfate for solubilization of MTT formazan crystal. (5) Results of MTT assay and colony assay were well correlated.