Regulatory pathways and drugs associated with ferroptosis in tumors.

Ferroptosis is a type of cell death that depends on iron and reactive oxygen species (ROS). The accumulation of iron and lipid peroxidation primarily initiates oxidative membrane damage during ferroptosis. The core molecular mechanism of ferroptosis includes the regulation of oxidation and the balance between damage and antioxidant defense. Tumor cells usually contain a large amount of H2O2, and ferrous/iron ions will react with excessive H2O2 in cells to produce hydroxyl radicals and induce ferroptosis in tumor cells. Here, we reviewed the latest studies on the regulation of ferroptosis in tumor cells and introduced the tumor-related signaling pathways of ferroptosis. We paid particular attention to the role of noncoding RNA, nanomaterials, the role of drugs, and targeted treatment using ferroptosis drugs for mediating the ferroptosis process in tumor cells. Finally, we discussed the currently unresolved problems and future research directions for ferroptosis in tumor cells and the prospects of this emerging field. Therefore, we have attempted to provide a reference for further understanding of the pathogenesis of ferroptosis and proposed new targets for cancer treatment.

Green Synthesis of Nitrogen-Doped Carbon Dots from Fresh Tea Leaves for Selective Fe3+ Ions Detection and Cellular Imaging.

In this research, we successfully developed a green, economical and effective one-step hydrothermal method for the synthesis of fluorescent nitrogen-doped carbon dots (N-CDs) by utilizing fresh tea leaves and urea as the carbon and nitrogen sources, respectively. The obtained N-CDs were characterized by TEM, XPS and FT-IR. We found that the N-CDs were near-spherical with an average size of about 2.32 nm, and contained abundant oxygen and nitrogen functional groups. The N-CDs exhibited bright blue fluorescence under ultraviolet illumination, with the maximum emission at 455 nm. Meanwhile, the as-prepared N-CDs could be selectively quenched by Fe3+ ions. The quenching of N-CDs is linearly correlated with the concentration of Fe3+ in the range of 0.1-400 µM with a low detection limit of 0.079 µM. Significantly, the N-CDs present excellent biocompatibility and high photostability. The results also depict that multicolor fluorescence is displayed under a fluorescence microscope and successfully applied for the detection of intracellular Fe3+. To sum up, the fluorescent N-CDs are expected to be a sensitive detection probe for Fe3+ in biological systems.