Nobiletin Induces Ferroptosis in Human Skin Melanoma Cells Through the GSK3β-Mediated Keap1/Nrf2/HO-1 Signalling Pathway

Abstract

Melanoma is an aggressive malignant skin tumour with an increasing global incidence. However, current treatments have limitations owing to the acquired tumour drug resistance. Ferroptosis is a recently discovered form of programmed cell death characterised by iron accumulation and lipid peroxidation and plays a critical role in tumour growth inhibition. Recently, ferroptosis inducers have been regarded as a promising therapeutic strategy to overcome apoptosis resistance in tumour cells. In this study, we reported that nobiletin, a natural product isolated from citrus peel, and exhibited antitumour activity by inducing ferroptosis in melanoma cells. Subsequently, we further explored the potential mechanism of nobiletin-induced ferroptosis, and found that the expression level of glycogen synthase kinase 3β (GSK3β) in the skin tissue of patients with melanoma was significantly reduced compared to that in the skin of normal tissue. Additionally, nobiletin increased GSK3β expression in melanoma cells. Moreover, the level of Kelch-like Ech-associated protein-1 (Keap1) was increased, while the level of nuclear factor erythroid 2-related factor 2 (Nrf2), and haem oxygenase-1 (HO-1) was decreased in nobiletin-treated melanoma cells, suggesting that the antioxidant defence system was downregulated. Furthermore, knockdown of GSK3β significantly reduced nobiletin-induced ferroptosis and upregulated the Keap1/Nrf2/HO-1 signalling pathway, while the opposite was observed in cells overexpressing GSK3β. In addition, molecular docking assay results indicated that nobiletin showed strong binding affinities for GSK3β, Keap1, Nrf2, and HO-1. Taken together, our results demonstrated that nobiletin could induce ferroptosis by regulating the GSK3β-mediated Keap1/Nrf2/HO-1 signalling pathway in human melanoma cells. Hence, nobiletin stands as a promising drug candidate for melanoma treatment with development prospects.

The dual role of Nrf2 in melanoma: a systematic review

“…Therefore, inducing ferroptosis following Nrf2 suppression has the potential to overcome tumor cell apoptosis resistance. Nobiletin, a natural product extracted from citrus peel, can induce ferroptosis by GSK3β-mediated downregulation of the Nrf2/HO-1 axis [ 53 ].…”

“… Nobiletin stimulates ferroptosis in melanoma cells by GSK3β-mediated suppression of the Nrf2/HO-1 axis. [ 53 ] Li et al, 2022 A375 human melanoma cell line Dimethyl fumarate (DMF) suppresses the Nrf2 antioxidant pathway as well as AKT/mTOR/ERK signaling pathways, causing ROS accumulation. The combination of DMF with vemurafenib significantly reduced melanoma cell growth and increased tumor cell death in vitro and in vivo.…”

Tumor Cell Derived Exosomal GOT1 Suppresses Tumor Cell Ferroptosis to Accelerate Pancreatic Cancer Progression by Activating Nrf2/HO-1 Axis via Upregulating CCR2 Expression

“…HO-1, an important source of cellular iron ions, plays a key role in erastin induced cell ferroptosis by inducing the peroxidation of cell membrane lipids, which causes cells to undergo ferroptosis. There have been numerous studies showing that Nrf2 can suppress ferroptosis by increasing the expression of target genes related to iron and ROS metabolism including HO-1 [ 15 , 16 ]. Moreover, exosome treatment enhanced the ability of cell invasion and clonogenicity, and the transfection of si-GOT1 reversed the effect of exosomes, but in the effect of NK-252, the ability of tumor cell invasion ( Figure 7 B) and clonogenicity ( Figure 7 C) was again enhanced.…”

Ferroptosis and Its Role in Chronic Diseases

“…Nobiletin, a critical active flavonoid in citrus fruits, was found to reduce ferroptosis-related renal injury, inflammation, and fibrosis in a unilateral ureteral obstruction mouse model [228]. Nobiletin triggers the ferroptosis of human skin melanoma cells via the GSK3β-mediated Keap1/Nrf2/HO-1 signaling pathway [229].…”