NCIt definition : A 4-aminoquinoline with antimalarial, anti-inflammatory, and potential chemosensitization
and radiosensitization activities. Although the mechanism is not well understood,
chloroquine is shown to inhibit the parasitic enzyme heme polymerase that converts
the toxic heme into non-toxic hemazoin, thereby resulting in the accumulation of toxic
heme within the parasite. This agent may also interfere with the biosynthesis of nucleic
acids. Chloroquine's potential chemosensitizing and radiosensitizing activities in
cancer may be related to its inhibition of autophagy, a cellular mechanism involving
lysosomal degradation that minimizes the production of reactive oxygen species (ROS)
related to tumor reoxygenation and tumor exposure to chemotherapeutic agents and radiation.;