Reactive oxygen species nanoamplifiers with multi-enzymatic activities for enhanced tumor therapy.

The ingenious combination of nano-enzymes with multi-enzyme activities and therapeutic drugs that can promote reactive oxygen species (ROS) production in cancer cells will enhance the therapeutic efficacy of nanomedicines on malignant tumors by amplifying oxidative stress. Herein, PEGylated Ce-doped hollow mesoporous silica nanoparticles (Ce-HMSN-PEG) loaded with saikosaponin A (SSA) are elaborately constructed as a smart nanoplatform for improving the efficiency of tumor therapy. The carrier Ce-HMSN-PEG showed multi-enzyme activities due to the presence of mixed Ce3+/Ce4+ ions. In the tumor microenvironment, peroxidase-like Ce3+ ions convert endogenous H2O2 into highly toxic ˙OH for chemodynamic therapy, while Ce4+ ions not only show catalase-like activity to reduce tumor hypoxia but also exhibit glutathione (GSH) peroxidase-mimicking properties to effectively deplete GSH in tumor cells. Moreover, the loaded SSA can cause the enrichment of superoxide anions (˙O2-) and H2O2 within tumor cells by disrupting mitochondrial functions. By integrating the respective advantages of Ce-HMSN-PEG and SSA, the as-prepared SSA@Ce-HMSN-PEG nanoplatform can efficiently trigger cancer cell death and inhibit tumor growth via significantly enhanced ROS production. Therefore, this positive combination therapy strategy has a good application prospect for enhancing antitumor efficacy.

An Ultrasound-Triggered Nanoplatform for Synergistic Sonodynamic-Nitric Oxide Therapy.

Ultrasound (US)-triggered sonodynamic therapy (SDT) has aroused intensive interest as a powerful alternative for cancer treatment in recent years due to its non-invasiveness and deep tissue penetration. However, the therapeutic effect of SDT alone is still limited by intrinsic hypoxia in solid tumors. Combined synergistic therapy strategies are highly desired for improving therapeutic efficiency. Herein, a rationally designed intelligent theranostic nanoplatform is developed for the enhancement of cancer treatment through synergistic SDT and nitric oxide (NO) therapy. This US-triggered nanoplatform is fabricated by integrating a sonosensitizer Rose Bengal (RB) and a NO donor (SNO) into manganese-doped hollow mesoporous silica nanoparticles (MH-SNO@RB). Impressively, the acidic and reducing tumor microenvironment accelerates the sustainable release of Mn ions from the framework, which facilitates the MH-SNO@RB to be used as a contrast agent for magnetic resonance imaging. More importantly, the reactive oxygen species (ROS) generated by RB and NO molecules released from SNO, which are simultaneously triggered by US, can react with each other to yield highly reactive peroxynitrite (ONOO-) ions for effective tumor inhibition both in vitro and in vivo. Furthermore, the nanoplatform demonstrates good hemocompatibility and histocompatibility. This study opens a new strategy for the full utilization of US and intelligent design avenues for high-performance cancer treatment.