Cytotoxicity of ketoconazole in malignant cell lines

The cytotoxic effects of ketoconazole, an antifungal agent known to have some activity against human prostate cancer, adrenal cancer, and male metastatic breast cancer, were evaluated using colony-growth and clonogenic assays in eight malignant cell lines. The cytotoxicity of ketoconazole showed a dose- and time-dependent pattern, with the following concentrations inhibiting 90% of the growing colonies (IC90): MCF 7 (human breast cancer) 7.25 micrograms/ml, T 47 D (human breast cancer) 9.0 micrograms/ml, MiaPaCa (human pancreatic carcinoma) 10.0 micrograms/ml, COLO 357 (human pancreatic carcinoma), 9.5 micrograms/ml, HCT 8 (human colonic adenocarcinoma) 27.1 micrograms/ml, DU 145 (human prostatic cancer) 40.0 micrograms/ml, AR 42 J (rat pancreatic carcinoma) 9.0 micrograms/ml, and L1210 (murine leukemia) 8.6 micrograms/ml. Since a concentration of 10 micrograms/ml can be achieved in humans, the use of ketoconazole in human malignancies might be worthy of clinical evaluation.