Bystander Effect of Sonodynamic Therapy in the presence of Gold Nanoparticles: An in-vitro study

Background: Bystander (B.s) effect can influence non-irradiated cells and affect the desired effect in cancer treatment. This study was conducted to assess this effect on simultaneous administration of ultrasound (US) and Gold nanoparticles as a sonodynamic therapy (SDT) which is an important newly stimuli-responsive method in cancer treatment. Materials and Methods: Firstly, the appropriate concentration of Gold nanoparticles (GNPs) and US intensity for SDT on melanoma cancer cells (A375) were evaluated. After treatments, the target cell culture was transferred to the bystander cells and the induced bystander effects including cell viability, apoptosis, expression of P53 (a promoter of apoptosis gene) and HO-1 (an inhibitor of apoptosis gene) were examined. Results: According to the MTT results, 50 mu g/ml concentration of GNPs and 1.5 W/cm2 intensity of US wave were selected. Our results revealed that SDT induced B.s effect can alter the cell viability and apoptosis up to 20% and 51.61%, respectively. Moreover, a 2.9-fold increase in p53 gene expression and a decrease in OH-1 gene expression to 0.181-fold in comparison to the control groups were observed. Conclusions: These results confirmed that B.s effect of sonodynamic can reduce the cancerous cell viability. Our finding showed that this treatment can be an alternative to traditional treatment modalities.