Abstract

   Ferroptosis induction through the suppression of glutathione peroxidase
   4 (GPX4) and apoptosis-inducing factor mitochondria-associated 2
   (AIFM2) has proven to be an effective approach in eliminating
   chemotherapy-resistant cells of various types. However, a comprehensive
   understanding of the roles of GPX4 and AIFM2 in acute myeloid leukemia
   (AML) has not yet been achieved. Using cBioPortal, DepMap, GEPIA,
   Metascape, and ONCOMINE, we compared the transcriptional expression,
   survival data, gene mutation, methylation, and network analyses of
   GPX4- and AIFM2-associated signaling pathways in AML. The results
   revealed that high expression levels of GPX4 and AIFM2 are associated
   with an adverse prognosis for AML patients. Overexpression of AIFM2
   correlated with elevated mutation frequencies in NPM1 and DNMT3A. GPX4
   upregulation modulated the following pathways: GO:0045333, cellular
   respiration; R-HSA-5389840, mitochondrial translation elongation;
   GO:0009060, aerobic respiration; R-HSA-9609507, protein localization;
   and R-HSA-8953854, metabolism of RNA. On the other hand, the
   overexpression of AIFM2 influenced the following processes: GO:0048704,
   embryonic skeletal system morphogenesis; GO:0021546, rhombomere
   development; GO:0009954, proximal/distal pattern formation; and
   GO:0048732, gland development. This study identifies the high
   expression of GPX4 and AIFM2 as novel biomarkers predicting a poor
   prognosis for AML patients. Furthermore, ferroptosis induction may
   improve the stratified treatment of AML.

   Keywords: acute myeloid leukemia, ferroptosis, glutathione peroxidases
   4, apoptosis-inducing factor mitochondria-associated 2, chemotherapy
   resistant

INTRODUCTION

   Acute myeloid leukemia (AML) comprises a group of heterogeneous
   hematologic malignancies characterized by an increased number of
   cytogenetic and molecular abnormalities, imposing a profound burden on
   affected individuals worldwide [[44]1, [45]2]. Despite advancements in
   AML treatment, such as risk stratification, combination chemotherapy,
   and stem cell transplantation, the overall survival rate remains
   unsatisfactory [[46]3, [47]4]. While the genomic landscape of AML has
   been extensively characterized, revealing numerous potential
   therapeutic targets, but how to effectively kill AML cells while
   leaving healthy cells uninjured remains a fundamental challenge.

   Ferroptosis induction, an iron-dependent form of necrotic cell death
   triggered by excessive peroxidation of polyunsaturated fatty acids
   (PUFAs), is being explored as an alternative approach to eradicate
   apoptosis-resistant cancer cells [[48]5, [49]6]. Ferroptosis is
   identified with hallmarks that are distinct from those of apoptosis; it
   is characterized by excessive iron-catalyzed peroxidation of
   PUFA-containing phospholipids (PLs) and is extensive in the mammalian
   cell membrane [[50]7–[51]9]. PL peroxidation is primarily mediated by
   reactive oxygen species (ROS) and the activity of the lipoxygenase
   (LOX) family. Failure to initiate protective mechanisms against
   peroxidation-induced membrane rupture leads to the induction of
   ferroptosis [[52]10, [53]11]. Consequently, ferroptosis is associated
   with a series of metabolic disorders, including those involving ROS,
   iron, and PLs. Abnormal genes and pathways related to the metabolism of
   iron, energy, oxidative stress, and lipid peroxidation may potentially
   modify cell sensitivity to ferroptosis.

   Phospholipid (PL) detoxification is typically regulated by the
   glutathione peroxidase (GPX) family [[54]12]. To date, GPX4 stands out
   as the sole GPX responsible for safeguarding membranes against
   peroxidative damage, and GPX4 functions in a glutathione
   (GSH)-dependent manner to reduce lipid hydroperoxide levels [[55]13,
   [56]14]. Depletion of intracellular GSH or the inhibition of GSH
   synthesis can indirectly deactivate GPX4, leading to the induction of
   ferroptosis [[57]15].

   Beyond GPX4, ferroptosis suppressor protein 1 (FSP1), also known as
   apoptosis-inducing factor mitochondria-associated 2 (AIFM2), has
   recently been identified as another player in suppressing ferroptosis,
   particularly in the context of GPX4 knockout. AIFM2 protects against
   ferroptosis through a glutathione-independent mechanism mediated by
   ubiquinone (CoQ[10]). This compound neutralizes lipid peroxyl radicals,
   moderating PL peroxidation. AIFM2 catalyzes the production of CoQ[10]
   via NAD(P)H. Therefore, the AIFM2-CoQ[10]-NAD(P)H pathway constitutes a
   parallel system that coordinates with GPX4 and glutathione to maintain
   the homeostasis of phospholipid peroxidation and ferroptosis [[58]16].

   Studies have demonstrated that inducing ferroptosis may effectively
   eliminate chemotherapy-resistant cancer cells in ovarian cancer, breast
   cancer, and lung cancer, highlighting the potential of ferroptosis
   induction as a novel anticancer therapy [[59]17, [60]18]. Consequently,
   various ferroptosis inducers (FIs) have gained approval from the Food
   and Drug Administration (FDA) for clinical use [[61]19]. However, the
   evaluation of the ferroptosis landscape has not been conducted in the
   context of AML. In this study, we utilized widely accepted public
   databases to assess ferroptosis resistance in AML, revealing a
   relationship between ferroptosis regulatory genes and the pathogenesis
   and progression of AML.

RESULTS

Transcriptional levels of GPX4 and AIFM2 in patients with AML

   GPX4 and AIFM2 are genes identified in the human genome. To compare
   their transcriptional levels in cancer and normal controls, we utilized
   the ONCOMINE database ([62]Figure 1). ONCOMINE analysis revealed an
   upregulation of GPX4 and AIFM2 mRNA expression in patients with AML
   ([63]Table 1). Specifically, GPX4 showed upregulation in 3 datasets,
   while AIFM2 was overexpressed in 1 dataset. Haferlach’s research
   indicated a 1.334-fold increase in GPX4 mRNA in AML [[64]20]. Andersson
   and colleagues reported a 1.74-fold elevation of GPX4 in AML [[65]21],
   and Valk identified GPX4 with a fold change of 1.257 in AML [[66]22].
   Regarding AIFM2 mRNA expression, Haferlach found a 1.069-fold increase
   in AML [[67]20].

Figure 1.

   Figure 1
   [68]Open in a new tab

   The transcription levels of GPX4 and AIFM2 in different types of
   cancers.

Table 1. The significant changes of GPX4 and AIFM2 expression in
transcription level between different types of leukemia and normal control.

   GENE Type of leukemia versus normal samples Fold change P value T test
   References