Hypothetic illustration of phototoxicity of PcGal16 in human bladder cancer cells.

The uptake of PcGal16 by bladder cancer cells is modulated by the presence of carbohydrate-binding proteins present at the cell surface (i.e. GLUT1 and galectin-1). PcGal16 is a nontoxic compound per se, and has high photocytotoxic efficiency against bladder cancer cell lines. Treatment with ROS quenchers demonstrated that cell death in bladder cancer cells is mediated by the production of ROS after PDT. Immediately after PDT with PcGal16 there is an increase on the activity of antioxidant enzymes (SOD, CAT and GR antioxidant enzymes). The photoactivated PcGal16 co-localizes with galectin-1 and GLUT1and reduces their levels.