2.8. MTT assay

Following 24, 48, and 72 h of transfection with miRNA mimics, inhibitors, or negative controls, cells were incubated with 20 μL 5 mg·mL⁻¹ MTT (thiazolyl blue tetrazolium bromide; Sigma‐Aldrich, Saint Louis, MO, USA) in PBS at 37 °C for 3 h. Then, the cells were lysed with lysis buffer (4 mm HCl, 0.1% NP40 in isopropanol), to solubilize the colored crystals. OD (optical density) was measured at 540 and 650 nm (reference) on a microplate reader (Tecan, Männerdorf, Switzerland). Each experiment contained three replicate wells and was repeated three times.