CA-5f neither impairs the hydrolytic function nor the quantity of lysosomes. Treatment of human umbilical vein endothelial cells (HUVECs) with CA-5f for 1 h suppresses the levels of cytoskeletal proteins and membrane traffic proteins. CA-5f exhibits strong cytotoxicity against A549 non-small cell lung cancer (NSCLC) cells, but low cytotoxicity to normal human umbilical vein endothelial cells (HUVECs), by increasing mitochondrial-derived reactive oxygen species (ROS) production. CA-5f inhibits autophagic flux by blocking autophagosome-lysosome fusion instead of affecting the pH and hydrolytic function of lysosomes.
In vivo
CA-5f effectively suppresses the growth of A549 lung cancer xenograft as a single agent with an excellent tolerance in vivo. It inhibits autophagic flux, induced apoptosis, and does not affect the level of CTSB (cathepsin B) and CTSD (cathepsin D) in vivo.