Smart Nanoplatforms Responding to the Tumor Microenvironment for Precise Drug Delivery in Cancer Therapy

Yujie Wang,1 Tingting Deng,1 Xi Liu,2 Xueyang Fang,1 Yongpan Mo,3 Ni Xie,4 Guohui Nie,1 Bin Zhang,1 Xiaoqin Fan1,4 1Shenzhen Key Laboratory of Nanozymes and Translational Cancer Research, Department of Otolaryngology, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital, Shenzhen, 518035, People’s Republic of China; 2Department of Nephrology, Shenzhen Longgang Central Hospital, Shenzhen, 518116, People’s Republic of China; 3Department of Breast Surgery, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital, Shenzhen, 518035, People’s Republic of China; 4The Bio-Bank of Shenzhen Second People’s Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital, Shenzhen, Guangdong, 518035, People’s Republic of ChinaCorrespondence: Bin Zhang; Xiaoqin Fan, Email binzhang@email.szu.edu.cn; fanxiaoqin83@163.comAbstract: The tumor microenvironment (TME) is a complex and dynamic entity, comprising stromal cells, immune cells, blood vessels and extracellular matrix, which is intimately associated with the occurrence and development of cancers, as well as their therapy. Utilizing the shared characteristics of tumors, such as an acidic environment, enzymes and hypoxia, researchers have developed a promising cancer therapy strategy known as responsive release of nano-loaded drugs, specifically targeted at tumor tissues or cells. In this comprehensive review, we provide an in-depth overview of the current fundamentals and state-of-the-art intelligent strategies of TME-responsive nanoplatforms, which include acidic pH, high GSH levels, high-level adenosine triphosphate, overexpressed enzymes, hypoxia and reductive environment. Additionally, we showcase the latest advancements in TME-responsive nanoparticles. In conclusion, we thoroughly examine the immediate challenges and prospects of TME-responsive nanopharmaceuticals, with the expectation that the progress of these targeted nanoformulations will enable the exploitation, overcoming or modulation of the TME, ultimately leading to significantly more effective cancer therapy. Keywords: tumor microenvironment, stimulus-responsive, drug delivery, cancer therapy, intelligent biomedicine