Cu2+-Pyropheophorbide a-Cystine Conjugate: Synergistic Photodynamic/Chemodynamic Therapy and Glutathione Depletion Improves the Antitumor Efficacy and Downregulates the Hypoxia-Inducing Factor

/CC multiplied the antitumor efficacy of CuPPaCC. The photo-chemocycloreaction continued to produce oxygen and maintained high ROS levels even after PDT, significantly alleviating hypoxia in the TME and downregulating the expression of HIF-1α. CuPPaCC thus showed excellent antitumor activity in vitro and in vivo. These results showed that the strategy could be effective in improving the antitumor efficacy of CuPPaCC and could be used as a synergistic regimen for cancer therapy.