Investigation of Endoplasmic Reticulum Stress and Apoptosis Caused by Malachite Green-Mediated Sonodynamic Therapy in HL60 Cells

Abstract

Aim: Sonodynamic antitumor therapy is a promising, novel method for the treatment of cancer. To determine the effects of malachite green (MG) in the presence of ultrasound (US), MG was tested in vitro on HL60 cells at different concentrations as a sonodynamic compound. We investigated cell viability, morphology, and the occurrence of ER stress after MG-mediated sonodynamic therapy (SDT) in HL60 cells.
 Materials and Methods: Four groups were formed, including a control group, a group subjected to ultrasound (US) only, a group treated with various concentrations of MG, and a group treated with US using the same concentrations. The cells were treated with 1MHz ultrasound at 2 W/cm2 for 3 minutes. The assessment of cell viability was conducted 24 hours post-treatment through the utilization of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cell morphology and apoptotic index were determined using Giemsa staining, while GRP78 and PERK expressions were determined through immunocytochemistry staining.
 Results: The cell cytotoxicity of HL60 cells significantly increased after MG-mediated sonodynamic therapy. After treatment, apoptotic cells with micronuclei were observed morphologically. Significant levels of GRP78 and PERK expression were observed in all groups, except for PERK expression in the US group, compared to the control group.
 Conclusion: The induction of ER stress, accompanied by intense apoptosis and a marked decrease in cell viability, demonstrates the potential of MG-mediated sonodynamic therapy in cancer treatment. Investigating ER stress as a molecular target may contribute to improving the treatment method.