Photothermia at the nanoscale induces ferroptosis via nanoparticle degradation

Metal ion interference therapy: metal-based nanomaterial-mediated mechanisms and strategies to boost intracellular "ion overload" for cancer treatment

Metal ion interference therapy (MIIT) has emerged as a promising approach in the field of nanomedicine for combatting cancer. With advancements in nanotechnology and tumor targeting-related strategies, sophisticated nanoplatforms have emerged to facilitate efficient MIIT in xenografted mouse models. However, the diverse range of metal ions and the intricacies of cellular metabolism have presented challenges in fully understanding this therapeutic approach, thereby impeding its progress. Thus, to address these issues, various amplification strategies focusing on ionic homeostasis and cancer cell metabolism have been devised to enhance MIIT efficacy. In this review, the remarkable progress in Fe, Cu, Ca, and Zn ion interference nanomedicines and understanding their intrinsic mechanism is summarized with particular emphasis on the types of amplification strategies employed to strengthen MIIT. The aim is to inspire an in-depth understanding of MIIT and provide guidance and ideas for the construction of more powerful nanoplatforms. Finally, the related challenges and prospects of this emerging treatment are discussed to pave the way for the next generation of cancer treatments and achieve the desired efficacy in patients.

Iron Oxide Nanoparticles Inhibit Tumor Progression and Suppress Lung Metastases in Mouse Models of Breast Cancer

Systemic exposure to starch-coated iron oxide nanoparticles (IONPs) can stimulate antitumor T cell responses, even when little IONP is retained within the tumor. Here, we demonstrate in mouse models of metastatic breast cancer that IONPs can alter the host immune landscape, leading to systemic immune-mediated disease suppression. We report that a single intravenous injection of IONPs can inhibit primary tumor growth, suppress metastases, and extend survival. Gene expression analysis revealed the activation of Toll-like receptor (TLR) pathways involving signaling via Toll/Interleukin-1 receptor domain-containing adaptor-inducing IFN-β (TRIF), a TLR pathway adaptor protein. Requisite participation of TRIF in suppressing tumor progression was demonstrated with histopathologic evidence of upregulated IFN-regulatory factor 3 (IRF3), a downstream protein, and confirmed in a TRIF knockout syngeneic mouse model of metastatic breast cancer. Neither starch-coated polystyrene nanoparticles lacking iron, nor iron-containing dextran-coated parenteral iron replacement agent, induced significant antitumor effects, suggesting a dependence on the type of IONP formulation. Analysis of multiple independent clinical databases supports a hypothesis that upregulation of TLR3 and IRF3 correlates with increased overall survival among breast cancer patients. Taken together, these data support a compelling rationale to re-examine IONP formulations as harboring anticancer immune (nano)adjuvant properties to generate a therapeutic benefit without requiring uptake by cancer cells.

Boosting chemotherapy of bladder cancer cells by ferroptosis using intelligent magnetic targeting nanoparticles

A versatile nano-delivery platform was reported to enhance the tumor suppression effect of chemotherapy by augmenting tumor cells' ferroptosis. The platform consists of pomegranate-like magnetic nanoparticles (rPAE@SPIONs) fabricated by encapsulating superparamagnetic iron oxide nanoparticles (SPIONs) within a reduced poly(β-amino ester)s-PEG amphiphilic copolymer (rPAE). The resulting platform exhibits several functionalities. Firstly, it promotes the doxorubicin (DOX) release by leveraging the mild hyperthermia generated by NIR irradiation. Secondly, it triggers ferroptosis in tumor cells, inducing their demise. Thirdly, it induces polarization of macrophages towards an anti-tumor M1 phenotype, contributing to ferroptosis of tumor cells and enhanced tumor cell suppression. This study effectively capitalizes on the versatility of SPIONs and offers a simple yet powerful strategy for developing a new nanosized ferroptosis-inducing agent, ultimately improving the inhibition of bladder cancer cells.

Emergence of magnetic nanoparticles in photothermal and ferroptotic therapies

With their distinctive physicochemical features, nanoparticles have gained recognition as effective multifunctional tools for biomedical applications, with designs and compositions tailored for specific uses. Notably, magnetic nanoparticles stand out as first-in-class examples of multiple modalities provided by the iron-based composition. They have long been exploited as contrast agents for magnetic resonance imaging (MRI) or as anti-cancer agents generating therapeutic hyperthermia through high-frequency magnetic field application, known as magnetic hyperthermia (MHT). This review focuses on two more recent applications in oncology using iron-based nanomaterials: photothermal therapy (PTT) and ferroptosis. In PTT, the iron oxide core responds to a near-infrared (NIR) excitation and generates heat in its surrounding area, rivaling the efficiency of plasmonic gold-standard nanoparticles. This opens up the possibility of a dual MHT + PTT approach using a single nanomaterial. Moreover, the iron composition of magnetic nanoparticles can be harnessed as a chemotherapeutic asset. Degradation in the intracellular environment triggers the release of iron ions, which can stimulate the production of reactive oxygen species (ROS) and induce cancer cell death through ferroptosis. Consequently, this review emphasizes these emerging physical and chemical approaches for anti-cancer therapy facilitated by magnetic nanoparticles, combining all-in-one functionalities.