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.