Cyclophosphamide Induces the Ferroptosis of Tumor Cells Through Heme Oxygenase-1.

Hezhan Shi,Huifeng Li,Bo Hou,Hui Zhou,Bin Du

doi:10.3389/fphar.2022.839464

Abstract

Ferroptosis has been implicated in the therapeutic responses of various types of tumors. Cyclophosphamide (CTX), one of the most successful antitumor agents, is widely used to treat both hematopoietic and solid tumors. In this study, we revealed the ferroptosis pathway targeted by CTX treatment in tumor cells and clarified its mechanisms. Cell viability was remarkably suppressed by CTX, accompanied by the accumulation of intracellular iron and reactive oxygen species (ROS), reduced glutathione levels, deformed mitochondria and a loss of the mitochondrial membrane potential. These effects were impeded by the ferroptosis inhibitors ferrostatin-1 (Fer1) and deferoxamine (DFO). Moreover, CTX treatment obviously upregulated nuclear factor E2 related factor 2 (NRF2) and heme oxygenase-1 (HMOX-1) expression. Additionally, the HMOX-1 inducer Hemin notably enhanced CTX-mediated tumor inhibition in vitro and in vivo through a mechanism that involved interfering with the ferroptosis process. Therefore, our findings indicated ferroptosis induction by CTX through the activation of the NRF2/HMOX-1 pathway, which might provide a potential strategy for tumor chemotherapy.

Highlights

Cyclophosphamide (CTX) is a commonly utilized broad-spectrum anticancer drug in clinical chemotherapy
We first performed RNA sequencing in GL261 murine glioblastoma cells treated with 4-hydroxycyclophosphamide (4HC), the pharmacologically active moiety of CTX, to systematically investigate the biological processes underlying the therapeutic effect of CTX
The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis based on RNA-seq data revealed enriched pathways related to ferroptosis, suggesting that iron homeostasis was among the pathways that were remarkably altered in 4-Hydroperoxy cyclophosphamide (4HC)-treated cells (Figure 1A)

Summary

Introduction

Cyclophosphamide (CTX) is a commonly utilized broad-spectrum anticancer drug in clinical chemotherapy. The pharmacological mechanism of CTX has been explored in numerous studies, and it correlates with oxidative stress, inflammation, and apoptosis (Emadi et al, 2009). Unlike other types of programmed cell death (PCD), such as necrosis or apoptosis, ferroptosis, a newly discovered form of regulated cell death, depends on intracellular iron accumulation and subsequent lipid peroxidation and is related to factors such as glutathione (GSH) (Dixon et al, 2012; Yan et al, 2021). In addition to the induction of tissue injury and protective effects on various diseases, the activation of ferroptosis may be responsible for the remarkable anticancer activity of target drugs such as sulfasalazine, sorafenib, and artemisinin (Chen et al, 2021). Few studies have deciphered the mechanisms connecting CTX and ferroptosis

Methods

Results

Conclusion