CASP3 and colorectal cancer: Zhou et al. found that PDT treatment of colorectal cancer cells with a photosensitizer that specifically targets mitochondria induced elevated levels of mitochondrial ROS in the cells and induced colorectal cancer cells pyroptosis via the caspase 3/gasdermin E pathway.549 Besides, since photosensitizers often have hydrophobic properties that limit transport, nanomaterials combined with photosensitizers can better help the photosensitizer to localize in mitochondria.