Time-dependent exposure to venetoclax induces ferroptosis in human neuroblastoma cells via upregulated transferrin gene expression and lipid peroxidation

Abstract

Aim: Neuroblastoma is one of the most widely diagnosed extracranial tumors in pediatric patients with poor survival rates. Despite the available treatment options, alternative treatment strategies are required, especially for high-risk patients. Venetoclax (VTX) is a small-molecule inhibitor of the anti-apoptotic protein Bcl-2, originally approved for the treatment of acute myeloid and chronic lymphocytic leukemia. Mounting evidence indicates that VTX may also be a promising agent against other types of cancer. However, data on the alternative mechanisms of VTX toxicity are limited. The present study aimed to unveil the potential of the agent against neuroblastoma. The effect of VTX on iron metabolism and ferroptotic cell death in neuroblastoma cells was investigated for the first time.

Materials and Methods: Cell viability was determined using the MTT assay. Oxidative stress, intracellular iron content, and lysosomal integrity were visualized using confocal microscopy. The MDA assay was performed to detect lipid peroxidation. The expression of TFR, FPN1, and GPX4 was determined by RT-qPCR.

Results: VTX significantly reduced cell viability in a time- and concentration-dependent manner, which was reversed by the addition of ferroptosis inhibitors. Further experiments revealed that VTX induces ROS generation, leads to lysosomal degradation and iron accumulation followed by lipid peroxidation, all of which are ferroptosis markers. RT-qPCR analyses indicated that VTX upregulates TFR gene expression while downregulating GPX4 and FPN1.

Conclusion: The present study demonstrated for the first time that VTX activates ferroptotic pathways in neuroblastoma cells and may be considered as a promising agent for add-on therapies.