Using functional nanomaterials to target and regulate the tumor microenvironment: Diagnostic and therapeutic applications

Malignant tumors remain a major health burden throughout the world and effective therapeutic strategies are urgently needed. Cancer nanotechnology, as an integrated platform, has the potential to dramatically improve cancer diagnosis, imaging, and therapy, while reducing the toxicity associated with the current approaches. Tumor microenvironment is an ensemble performance of various stromal cells and extracellular matrix. The recent progress in understanding the critical roles and the underlying mechanisms of the tumor microenvironment on tumor progression has resulted in emerging diagnostic and therapeutic nanomaterials designed and engineered specifically targeting the microenvironment components. Meanwhile, the bio-physicochemical differences between tumor and normal tissues have recently been exploited to achieve specific tumor-targeting for cancer diagnosis and treatment. Here, the major players in the tumor microenvironment and their biochemical properties, which can be utilized for the design of multifunctional nanomaterials with the potential to target and regulate this niche, are summarized. The recent progress in engineering intelligent and versatile nanomaterials for targeting and regulating the tumor microenvironment is emphasized. Although further investigations are required to develop robust methods for more specific tumor-targeting and well-controlled nanomaterials, the applications of tumor microenvironment regulation-based nanotechnology for safer and more effective anticancer nanomedicines have been proven successful and will eventually revolutionize the current landscape of cancer therapy.