Magnetic nanoflower-mediated hyperthermia activates concurrent apoptosis and ferroptosis on prostate PC3 and melanoma...

Magnetic hyperthermia therapy (MHT) has many potential applications in cancer therapy due to its controllable heating, precise targeting, and biocompatibility; however, its underlying mechanisms of damaging cancer cells are still not fully understood. Herein, we employed magnetic nanoflowers (NFs) as a high-performance heating agent under an alternating magnetic field (AMF) to investigate the cytotoxic mechanisms of MHT on prostate cancer PC3 and melanoma DX3 cells. Cytotoxicity assays (CCK-8, trypan blue, and clonogenic assay) were conducted to confirm viability loss in both cell lines. Flow cytometry for reactive oxygen species (ROS), Fe²⁺, and apoptosis detection, combined with glutathione (GSH) and lipid peroxidation assays, suggested that MHT can concurrently induce hallmarks of apoptosis and ferroptosis. Confocal microscopy visualised apoptotic progression, mitochondrial depolarisation, and lysosomal involvement. Western blotting (WB) further identified altered expression of key apoptotic markers (Caspase-3/7, Bax/Bcl-2) and ferroptosis regulators (FSP1, GPX4), confirming a mixed apoptotic-ferroptotic signal triggered by MHT. These mechanistic findings were also validated in 3D spheroid tumor models. Moreover, heat-generation studies in cells, test tubes, and chicken breast demonstrated NF's efficient and tunable thermal output. Additionally, heat mapping at the cellular level provided spatial-temporal profiles of intracellular temperature gradients, offering a novel framework for evaluating nanoscale thermal dissipation in MHT. Collectively, this work advances our understanding of the MHT mechanism and elucidates the therapeutic potential of NFs in inducing coordinated tumor cell death.