To produce lentiviral particles, HEK-293T cells were transfected with a mixture of plasmids: each shRNA expression plasmid (1 µg), pCMV-ΔR8.2dvpr packaging plasmid (0.75 µg), and pCMV-VSV-G envelope plasmid (0.25 µg) using Lipofectamine 2000 reagent (Invitrogen).