Inhibition of human transitional cell carcinoma in vitro proliferation by fluoroquinolone antibiotics

The in vitro effects of the fluoroquinolone antibiotics ciprofloxacin and ofloxacin upon 3 human transitional cell carcinoma cell lines were investigated at concentrations that are attainable in the urine of patients taking these drugs orally.

Cell lines TCCSUP, T24, and J82 were exposed in culture to either ciprofloxacin or ofloxacin at concentrations ranging from 0 to 800 micrograms./ml. and at durations ranging from 24 to 120 hours. Inhibition of proliferation and DNA synthesis were assessed via MTT and tritiated thymidine assays, respectively.

From the MTT assay ciprofloxacin, at concentrations of 25 to 800 micrograms./ml., produced proliferation inhibition in the TCCSUP line ranging from 8.1% to 90.2% at 24 hours, 25.1% to 94.9% at 72 hours, and 53.8% to 96.9% at 120 hours. Inhibition of proliferation for the T24 line ranged from 8.0% to 85%, 31.5% to 96.5%, and 27.3% to 98.2%. Inhibition of proliferation of the J82 line ranged from 20.8% to 84.8%, 22.8% to 92.7%, and 37.4% to 97.1%. Inhibition of DNA synthesis (due to ciprofloxacin at the concentrations above) as measured by the tritiated thymidine assay was also significant for each of the 3 cell lines. Inhibition of proliferation and DNA synthesis due to ofloxacin was lower but not overall statistically different from that due to ciprofloxacin. In a separate experiment, enhanced cytotoxicity was observed at lower concentrations of ciprofloxacin when the initial media pH was approximated to 5.5.

Ciprofloxacin and ofloxacin inhibit proliferation and DNA synthesis of these 3 human TCC lines in vitro. Inhibition occurred in a concentration- and time-dependent manner. The concentrations that were assessed are attainable in the urine of patients taking these agents orally.