Abstract

Aim: Neuroblastoma is among 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 the high-risk patients. Venetoclax (VTX) is a small molecule inhibitor of anti-apoptotic protein Bcl-2, originally approved for acute myeloid and chronic lymphocytic leukemia. Mounting evidence suggests that VTX may be a promising agent against other type of cancers as well. However, there are limited data on the alternative mechanisms of VTX toxicity. The aim of the present study was to unveil the true potential of the agent against neuroblastoma. In this regard, 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 with MTT assay. Oxidative stress, intracellular iron content and lysosomal integrity were visualized with confocal microscopy. MDA assay was performed to detect lipid peroxidation. The gene expressions of TFR, FPN1 and GPX4 were determined by RT-qPCR.
Results: Results showed that VTX reduces cell viability significantly in both 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: In conclusion, the present study demonstrated for the first time that VTX activates ferroptotic pathways in neuroblastoma cells and may be considered a promising agent for add-on therapies.

Key words: Ferroptosis, iron, neuroblastoma, oxidative stress, venetoclax.