Fe-doped carbon dots: a novel biocompatible nanoplatform for multi-level cancer therapy.

BACKGROUND: Tumor treatment still remains a clinical challenge, requiring the development of biocompatible and efficient anti-tumor nanodrugs. Carbon dots (CDs) has become promising nanomedicines for cancer therapy due to its low cytotoxicity and easy customization. RESULTS: Herein, we introduced a novel type of "green" nanodrug for multi-level cancer therapy utilizing Fe-doped carbon dots (Fe-CDs) derived from iron nutrient supplement. With no requirement for target moieties or external stimuli, the sole intravenous administration of Fe-CDs demonstrated unexpected anti-tumor activity, completely suppressing tumor growth in mice. Continuous administration of Fe-CDs for several weeks showed no toxic effects in vivo, highlighting its exceptional biocompatibility. The as-synthesized Fe-CDs could selectively induce tumor cells apoptosis by BAX/Caspase 9/Caspase 3/PARP signal pathways and activate antitumoral macrophages by inhibiting the IL-10/Arg-1 axis, contributing to its significant tumor immunotherapy effect. Additionally, the epithelial-mesenchymal transition (EMT) process was inhibited under the treatment of Fe-CDs by MAPK/Snail pathways, indicating the capacity of Fe-CDs to inhibit tumor recurrence and metastasis. CONCLUSIONS: A three-level tumor treatment strategy from direct killing to activating immunity to inhibiting metastasis was achieved based on "green" Fe-CDs. Our findings reveal the broad clinical potential of Fe-CDs as a novel candidate for anti-tumor nanodrugs and nanoplatform.

Ferroptosis: The Entanglement between Traditional Drugs and Nanodrugs in Tumor Therapy.

Ferroptosis is a non-apoptotic programmed cell death caused by the accumulation of lipid peroxide. System Xc-/glutathione peroxidase 4 (GPX4) axis and iron axis are two main pathways regulating ferroptosis. Simultaneously, multiple pathways are also involved in the ferroptosis regulation. Ferroptosis is an intense area of the current study. With the improvement of the regulatory mechanisms that underlie ferroptosis, a variety of drugs associated with ferroptosis have been discovered and developed for cancer therapy. Among them, traditional drugs were developed initially. Small molecule compounds that regulate ferroptosis signaling pathway and iron complexes that promote the Fenton reaction have become important drugs for inducing ferroptosis. In recent years, the emerging development of nanotechnology has promoted the research of ferroptosis nanodrugs. Iron-based nanomaterials are extensively tested as ferroptosis-inducing agents. Furthermore, nanoscale drug delivery systems offer a suitable scaffold for traditional drug therapies. Traditional drugs and nanodrugs are complementary, each with their own strengths and limitations. This review describes the latest studies on the regulation of ferroptosis in tumor cells and focuses on the entanglement between traditional drugs and nanodrugs. To conclude, the challenges and perspectives in this field are put forward.