Fig. 8: Induction of the SOS response by anti-cancer agents.
From: Antibacterial compounds against non-growing and intracellular bacteria
UPEC CFT073 harboring pAED2 was cultivated in 1:4 CA-MHB (pH 7.4) to assess SOS response induction by echinomycin (ECH), bleomycin (BLE), mitomycin C (MMC), and ofloxacin (OFL) (A), and in LPM (pH 5.5) to evaluate plicamycin (PLI), evofosfamide (EVO), and satraplatin (SAT) (B). The expression of the mScarlet-I reporter, controlled by the SOS-inducible cda’ promoter, was measured in a microplate. Growing cultures were treated with 20 μM of each compound for 6 h, while stationary-phase cultures were treated with 10 μM for 24 h. mScarlet fluorescence and OD600 were recorded at the start (start) and end of the incubation for both drug-free controls (control) and treated samples. Following treatment, stationary-phase bacteria were collected by centrifugation, washed, diluted 1:7 in CA-MHB, and incubated in a microplate. mScarlet fluorescence was recorded at the start of the incubation (start) and when OD600 reached approximately 0.5 for both the drug-free controls (control) and treated samples. Specific fluorescence units (SFU) were calculated by normalizing fluorescence (arbitrary units, AU) to cell density (OD600). Data are presented as means ± SEM for n = 3. Statistical significance was assessed using one-way ANOVA followed by Dunnett’s test, comparing each treatment to the drug-free control. Asterisks indicate p-values: ****p < 0.0001 and *p < 0.05. A single control experiment was performed using OFL.
