Shaping Tumor Microenvironment for Improving Nanoparticle Delivery

Background: Tumor microenvironment is so complex that involves in many factors of tumor. Although enhanced permeability and retention effect is a main driving force of tumor targeted nanoparticles, the tumor microenvironment greatly affects the delivery efficiency of nanoparticles. Methods: A careful search of the scientific database was performed to find the tumor microenvironment related papers. Then the papers were concluded and reviewed. Results: In tumor, elevated interstitial fluid pressure, abnormal tumor vasculature, dense tumor extracellular matrix and elevated solid stress considerably hinder the extravasation and intratumor penetration of nanoparticles. Therefore, shaping the tumor microenvironment could improve nanoparticle delivery, including vascular normalization, vasculature promotion therapy, lymph normalization, reducing tumor stroma components, elevating blood pressure, elevating receptor expression, cell cycle arrest and priming by cytotoxic therapy. Conclusion: Shaping the tumor microenvironment could considerably enhance the nanoparticles delivery.