Realgar Nanoparticles Induced Cytotoxicity in Promyelocytic Leukemia HL-60 Cells

Realgar induced nephrotoxicity via ferroptosis in mice

Ferroptosis is a novel form of iron-dependent cell death that is involved in arsenic-induced toxicity. Realgar is an arsenic-containing Chinese medicine, which can result in nephrotoxicity because of long-term exposure. However, it remains scientifically unknown whether Realgar is an inducer of ferroptosis in the kidney. This study investigated the role of ferroptosis in Realgar-induced kidney toxicity in mice. ICR mice were exposed to Realgar for 28 days and HK2 cells were exposed to Realgar in the presence or absence of treatment with ferrostatin-1, a ferroptosis inhibitor. The ferroptosis-related indicators were further evaluated. Realgar can cause nephrotoxicity in mice by continuous gavage for 28 days, accompanied by an increase in iron accumulation and reactive oxygen species. The reduced expression of Slc7A11 and Gpx4 further confirmed the ferroptosis mediated by Realgar. Meanwhile, Realgar disrupted the antioxidant system as evidenced by the formation of ROS leading to the inactivation of antioxidant enzymes. Realgar caused ferroptosis in a dose-dependent manner, which was significantly reduced by ferrostatin-1 in HK2 cells. This study revealed that Realgar-induced ferroptosis triggered nephrotoxicity in mice and provided new clues to elucidate the mechanism of Realgar-induced nephrotoxicity.

Arsenic in cancer treatment: challenges for application of realgar nanoparticles (a minireview)

While intensive efforts have been made for the treatment of cancer, this disease is still the second leading cause of death in many countries. Metastatic breast cancer, late-stage colon cancer, malignant melanoma, multiple myeloma, and other forms of cancer are still essentially incurable in most cases. Recent advances in genomic technologies have permitted the simultaneous evaluation of DNA sequence-based alterations together with copy number gains and losses. The requirement for a multi-targeting approach is the common theme that emerges from these studies. Therefore, the combination of new targeted biological and cytotoxic agents is currently under investigation in multimodal treatment regimens. Similarly, a combinational principle is applied in traditional Chinese medicine, as formulas consist of several types of medicinal herbs or minerals, in which one represents the principal component, and the others serve as adjuvant ones that assist the effects, or facilitate the delivery, of the principal component. In Western medicine, approximately 60 different arsenic preparations have been developed and used in pharmacological history. In traditional Chinese medicines, different forms of mineral arsenicals (orpiment—As₂S₃, realgar—As₄S₄, and arsenolite—arsenic trioxide, As₂O₃) are used, and realgar alone is included in 22 oral remedies that are recognized by the Chinese Pharmacopeia Committee (2005). It is known that a significant portion of some forms of mineral arsenicals is poorly absorbed into the body, and would be unavailable to cause systemic damage. This review primary focuses on the application of arsenic sulfide (realgar) for treatment of various forms of cancer in vitro and in vivo.