Int J Biol Sci 2022; 18(1):374-385. doi:10.7150/ijbs.66602 This issue

Research Paper

Enhanced Intracellular Reactive Oxygen Species by Photodynamic Therapy Effectively Promotes Chemoresistant Cell Death

Xiaolin Xu1,2*, Chenglong Wang1*, Peipei Zhang3, Xuzhu Gao1, Wencai Guan1, Fanchen Wang1,2, Xin Li1,2, Jia Yuan1,2, Hongjing Dou3✉, Guoxiong Xu1,2✉

1. Research Center for Clinical Medicine, Jinshan Hospital, Fudan University, Shanghai 201508, China.
2. Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China.
3. State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
* These authors contributed equally to this work.

This is an open access article distributed under the terms of the Creative Commons Attribution License ( See for full terms and conditions.
Xu X, Wang C, Zhang P, Gao X, Guan W, Wang F, Li X, Yuan J, Dou H, Xu G. Enhanced Intracellular Reactive Oxygen Species by Photodynamic Therapy Effectively Promotes Chemoresistant Cell Death. Int J Biol Sci 2022; 18(1):374-385. doi:10.7150/ijbs.66602. Available from

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Graphic abstract

Anti-cancer chemo-drugs can cause a rapid elevation of intracellular reactive oxygen species (ROS) levels. An imbalance in ROS production and elimination systems leads to cancer cell resistance to chemotherapy. This study aimed to evaluate the mechanism and effect of ROS on multidrug resistance in various human chemoresistant cancer cells by detecting the changes in the amount of ROS, the expression of ROS-related and glycolysis-related genes, and cell death. We found that ROS was decreased while oxidative phosphorylation was increased in chemoresistant cells. We verified that the chemoresistance of cancer cells was achieved in two ways. First, chemoresistant cells preferred oxidative phosphorylation instead of anaerobic glycolysis for energy generation, which increased ATPase activity and produced much more ATP to provide energy. Second, ROS-scavenging systems were enhanced in chemoresistant cancer cells, which in turn decreased ROS amount and thus inhibited chemo-induced cell death. Our in vitro and in vivo photodynamic therapy further demonstrated that elevated ROS production efficiently inhibited chemo-drug resistance and promoted chemoresistant cell death. Taken together, targeting ROS systems has a great potential to treat cancer patients with chemoresistance.

Keywords: Chemoresistance, glycolysis, malignant tumor, oxidative phosphorylation, photodynamic therapy, ROS