To confirm that NPC1 protected cancer cells from pyroptosis by LDL uptake, we generated a NPC1 knockout (NPC1-KO) ARP-1 and HepG2 cells and reintroduced the wild-type (WT) or P691S mutant (NPC1P691S, which reduces NPC1 cholesterol transport [37]) NPC1 using lentivirus to the NPC1-KO cells. Here, NPC1 is linked to cancer.