ALDH1A1 Silencing. Cells were transfected with siRNA targeting ALDH1A1, control cells were mock-transfected. The transfected cells were cultured in antibiotic-free medium for 24 h, followed by culture in medium containing 4% BSA for 24 h. Total RNA was extracted and the transcript levels of ALDH1A1 were measured by RT-PCR. Data presented as mean +/- s.d. of n = 9 from 3 independent experiments.