MTT assay was used to evaluate cell viability and proliferation. MTT, a tetrazole with a yellow color, is taken up by living cells and then converted into a purple formazan-reduced state by mitochondrial dehydrogenase. Cells were seeded in a 96-well plate at a density of 8 × 103 cells per well and cultured for 24 h. Following attachment, cells were replaced in fresh medium with siRNA and transfection reagent complex and cultured for 48 h. Then, the medium was changed to fresh medium containing 100 µL of 0.5 mg/mL MTT and then cultured for 2 h at 37 °C under 5% CO2. Then, the medium was discarded and 100 µL DMSO was added to dissolve the formazan. The absorbance was measured at 595 nm .