WST-8 cell viability assay

WST-8 colorimetric cell viability was performed using the Cell Counting kit-8 (CCK-8) (Dojindo, Japan) according to the manufacturer’s instructions. Prostate cancer cells were seeded at a density of 1×10⁴ cells per well in 96-well plates. After overnight incubation, the medium was removed and replaced with DMEM containing 1% FBS. TRAIL in 0.1% BSA was added to each well. After 24-h treatment, WST-8 was added to each well, and plates were incubated for an additional 1 h at 37°C. Absorbance was measured at 450 nm. The experiments were repeated 4 times, and cell proliferation rate was calculated using the following formula: Proliferation rate=(OD test/OD control)×100%.