ABSTRACT
Hypoxia,a salient feature of solid tumors,is often associated with invasiveness,metastasis and resistance to anticancer drugs.The strategies including the use of oxygen-carriers based on hyperbaric oxygen and blood substitutes to transport oxygen into tumors or in situ generation of O2from the tumor microenvironment endogenous H2O2have been explored to relieve the tumor hypoxia and to improve therapeutic efficiency.In addi-tion,it is potential to design hypoxia-responsive nanocarriers based on tumor hypoxia microenvironment to deliver anticancer drugs to the targeted tumor site,thereby improve drug concentrations in targeted site,significantly increase the antitumor efficiency and reduce the side-effects of drugs.This review gives an overview of the advances in relieving tumor hypoxia and hypoxia-responsive nanocarriers for tumor to provide a reference for the research and development of new antitumor drugs.