Amorphous ferric oxide-coating selenium core-shell nanoparticles: a self-preservation Pt(IV) platform for multi-modal cancer therapies through hydrogen peroxide depletion-mediated anti-angiogenesis, apoptosis and ferroptosis.

A self-preservation Pt(IV) nanoplatform, amorphous ferric oxide-coating selenium core-shell nanoparticles (iAIO@NSe-Pt), was developed for H 2 O 2 depletion-mediated tumor anti-angiogenesis, apoptosis, and ferroptosis. Upon entry into the blood, the ferric oxide shell effectively blocked the contact Pt(IV) prodrug with reduced molecules, then avoided the inactivation of the Pt(IV) prodrug and increased its accumulation in the tumor. After entering cancer cells, iAIO@NSe-Pt caused a series of cascade reactions: (1) AIO on the surface of iAIO@NSe-Pt quickly dissolved, released an abundance of Fe(II) because of the weakly acidic tumor microenvironment, and then catalyzed cellular H 2 O 2 into highly toxic ˙OH, resulting in cellular H 2 O 2 deficiency and cell ferroptosis. (2) The platinum(IV) prodrugs were exposed and quickly reduced to highly toxic Pt(II) by depleting GSH. This process inactivated GPX4, promoted ROS accumulation, and further accelerated ferroptosis. In addition, the generated Pt(II) quickly inhibited DNA replication, achieving effective apoptotic cell death. Meanwhile, Pt(II) inactivated SOD1, which blocked the synthesis of cellular H 2 O 2 and accelerated ROS (superoxide anion radical) accumulation. (3) The deficiency of cellular H 2 O 2 significantly inhibited the expression of vascular endothelial growth factor-A (VEGF-A), blocking tumor angiogenesis and then improving the anticancer effect. (4) After such a cascade reaction, the exposed NSe successively disrupted mitochondrial respiration and inhibited cancer angiogenesis, further inducing cancer cell death. Collectively, our functional and mechanical investigation suggested that iAIO@NSe-Pt exhibits excellent tumor targeting, biocompatibility and anti-tumor efficiency in vitro and in vivo , and provides a novel example of a self-preservation Pt(IV) nanoplatform for H 2 O 2 depletion-mediated tumor anti-angiogenesis, apoptosis, and ferroptosis, showing great promise for future clinical use.