Nanoparticles designed to regulate tumor microenvironment for cancer therapy.

Increasing understanding in tumor pathology reveals that tumor microenvironment (TME), which supports tumor progression and poses barriers for available therapies, takes a great responsibility in inefficient treatment and poor prognosis. In recent years, the versatile nanotechnology employed in TME regulation has made great progress. The nanoparticles (NPs) can be tailored as needed to accurately target TME components by distinguishing healthy tissues from malignancy, and to regulate TME to promote tumor regression. Meanwhile, the emerging microRNAs (miRNAs) demonstrate great potentials for TME regulation, but are regrettably restricted by quick degradation. NPs systems enable the successful delivery of miRNA to TME without the limitation, expanding the application of nucleic acid drug. In this review, we summarized recent NPs-based strategies aiming at regulating TME in different ways, including anti-angiogenesis, extracellular matrix (ECM) remodeling, tumor-associated fibroblasts (TAFs) treatment and tumor-associated macrophages (TAMs) treatment, along with the miRNAs-loaded NPs for TME regulation. Catching and utilizing the features of TME for NPs design can contribute to reversing drug-resistance, optimized drug distribution, and eventually more efficient cancer therapy.