4.10. Sulforhodamine B (SRB) Assay

The cell proliferations of A549 and Met-5A cells were determined using the SRB assay. Cells (2 × 10⁴) were dispensed in a 96-well plate for 24 h. Before being treated with varying concentrations of AzP (5–50 μM) or SAHA (5–50 μM) for 48 h, cells were fixed in 10% trichloroacetic acid for 10 min and washed with distilled water twice to remove excess trichloroacetic acid. Cells were stained with a 0.4% SRB solution dissolved in 1% acetic acid for 10 min and washed with 1% acetic acid twice to remove excess dye. The protein-bound dye was dissolved in 100 μL Tris-based solution (10 mM), and the absorbance was measured at 515 nm using a microplate reader. Cell Proliferation % = {(T48 − T0)/T0} × 100. Wherein, T48 represents the signal measured after 48-h treatment, T0 represent the signal measured before treatment at time 0. Relative cell proliferation (%) were expressed as mean ± SD compare with control.