A Detailed Overview of ROS-Modulating Approaches in Cancer Treatment Nano-Based System To Improve Its Future Clinical Perspective Prathap Somu, Sonali Mohanty, and Subhankar Paul Contents Background ....................................................................................... 3 Role of Reactive Oxygen Species (ROS) in Normal Healthy and Cancer Cells ................ 4 Role of ROS in Normal Cells ................................................................. 4 Reactive Oxygen Species Role in Cancer Cells .............................................. 4 Cancer Treatment: ROS-Modulated Therapeutic Approaches .................................. 6 ROS Scavenging Anticancer Approaches (Antioxidant Therapy) ........................... 7 ROS-Promoting Therapy (Prooxidant Therapy) ............................................. 9 Need for Targeted Nanosystem Approach Delivery for Prooxidant Therapy ................... 10 Nanoparticles as Passive Agent: Drug Carrier ............................................... 11 Nanoparticles as Active Agent: Drug Carrier Cum PDT Agent ............................. 12 Conclusion ........................................................................................ 18 References ........................................................................................ 19 Abstract Reactive oxygen species (ROS) play an essential role in physiological functions as an intracellular signal-regulating molecule as well as in the pathophysiology condition of an organism like cancer, etc. In cancer, the critical characteristic that distinguishes it from normal healthy cells is the elevated level of ROS and extra dependence on its antioxidant defense system. Further, these elevated level of ROS has an essential role in cancer initiation, progression, and maintenance. Hence, the behavior of ROS in cancer cells has become a crucial target in cancer P. Somu Structural Biology and Nanomedicine Laboratory, Department of Biotechnology and Medical Engineering, National Institute of Technology, Rourkela, Odisha, India Department of Biotechnology, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences (Deemed to be University), Chennai, Tamilnadu, India S. Mohanty · S. Paul (*) Structural Biology and Nanomedicine Laboratory, Department of Biotechnology and Medical Engineering, National Institute of Technology, Rourkela, Odisha, India e-mail: spaul@nitrkl.ac.in © Springer Nature Singapore Pte Ltd. 2022 S. Chakraborti (ed.), Handbook of Oxidative Stress in Cancer: Therapeutic Aspects, https://doi.org/10.1007/978-981-16-1247-3_213-1 1