HCCSCs were infected with lentiviral particles encoding shRNA targeting p53 (Santa Cruz Biotechnology, Paso Robles, CA) according to the supplier's protocol. Briefly, HCCSCs were infected at a multiplicity of infection of 10 in HCCSC growth medium containing 5 μg/mL of Polybrene at 37°C and 5% CO2. After 24 hours, media were replaced with fresh media and the cells were cultured for 2 days. The infected cells were selected in the presence of puromycin (7.5 μg/mL) for 5 days. Protein extract from these cells was run on a gel to confirm complete suppression of p53 as described earlier [34].