Differential cytotoxicity and sonosensitization by sanazole: effect of cell type and acoustic parameters

Although sanazole has been used as a hypoxic radiosensitizer, we recently reported on its ability to sensitize U937 cells to hyperthermia and X-irradiation under aerobic conditions, enhancing apoptotic cell death following the combined treatment. The current study was undertaken to evaluate the effect of sanazole as a sonosensitizer under previously studied acoustic conditions of different pulse repetition frequencies, using two cell lines representative of solid tumours and haematopoietic cancers.

Cells were treated with different doses of sanazole. Flow-cytometric analysis and DNA fragmentation assay were carried out at different times, and morphological features were also inspected. For ultrasound treatment, cells were pre-incubated with a non-cytotoxic dose of sanazole for 30 min before exposure. Evaluation of cell killing and a parallel examination of intracellular oxidative stress levels in both cell lines were performed using flow cytometry.

Sanazole alone displayed selective cytotoxic effects towards solid tumour-derived cancer cells, resulting in complete cell death after 24 h of treatment, and enhanced the ultrasound-induced cell killing 6 h post-treatment. The enhancement seemed to be mediated by an additive increase in intracellular oxidative stress levels.

Sanazole seems to be an efficient cytotoxic agent for the treatment of solid tumours and a promising sonosensitizer under aerobic conditions.