Modulating tumor mechanics with nanomedicine for cancer therapy

Over the past several decades, the importance of the tumor mechanical microenvironment (TMME) in cancer progression or cancer therapy has been recognized by researchers worldwide. The abnormal mechanical properties of tumor tissues include high mechanical stiffness, high solid stress, and high interstitial fluid pressure (IFP), which form physical barriers resulting in suboptimal treatment efficacy and resistance to different types of therapy by preventing drugs infiltrating the tumor parenchyma. Therefore, preventing or reversing the establishment of the abnormal TMME is critical for cancer therapy. Nanomedicines can enhance drug delivery by exploiting the enhanced permeability and retention (EPR) effect, so nanomedicines that target and modulate the TMME can further boost antitumor efficacy. Herein, we mainly discuss the nanomedicines that can regulate mechanical stiffness, solid stress, and IFP, with a focus on how nanomedicines change abnormal mechanical properties and facilitate drug delivery. We first introduce the formation, characterizing methods and biological effects of tumor mechanical properties. Conventional TMME modulation strategies will be briefly summarized. Then, we highlight representative nanomedicines capable of modulating the TMME for augmented cancer therapy. Finally, current challenges and future opportunities for regulating the TMME with nanomedicines will be provided.