Small-sized twin-nanoparticles normalize tumor vasculature to enhance tumor accumulation and penetration for potent eradication of cancer stem-like cells

Cancer stem cells (CSCs) are proposed to account for the progression, metastasis, and recurrence of diverse malignancies. However, the disorganized vasculars in tumors hinder the accumulation and penetration of nanomedicines, posing a challenge in eliminating CSCs located distantly from blood vessels. Herein, a pair of twin-like small-sized nanoparticles, sunitinib (St)-loaded ROS responsive micelles (RM@St) and salinomycin (SAL)-loaded GSH responsive micelles (GM@SAL), are developed to normalize disordered tumor vessels and eradicate CSCs. RM@St releases sunitinib in response to the abundant ROS in the tumor extracellular microenvironment for tumor vessel normalization, which improved intratumor accumulation and homogeneous distribution of small-sized GM@SAL. Sequentially, GM@SAL effectively accesses CSCs and achieves reduction-responsive drug release at high GSH concentrations within CSCs. More importantly, RM@St significantly extends the window of vessel normalization and enhances vessel integrity compared to free sunitinib, thus further amplifying the anti-tumor effect of GM@SAL. The combination therapy of RM@St plus GM@SAL produces considerable depression of tumor growth, drastically reducing CSCs fractions to 5.6% and resulting in 78.4% inhibition of lung metastasis. This study offers novel insights into rational nanomedicines designed for superior therapeutic effects by vascular normalization and anti-CSCs therapy.