CircZBTB46 Protects Acute Myeloid Leukemia Cells from Ferroptotic Cell Death by Upregulating SCD

SIMPLE SUMMARY: It is urgent to identify new biomarkers for diagnosis, prognostication, and therapeutic targets of acute myeloid leukemia (AML) so as to develop more effective surveillance and treatment programs. Ferroptosis is a crucial, iron-dependent regulated cell death driven by excessive accumulation of lipid hydroperoxides. Accumulating evidence has proven that dysregulated ferroptosis is implicated in tumor progression and is becoming an emerging therapeutic target for the treatment of AML. However, the effect of circRNAs on ferroptosis and the development of AML remain unclear. In this study, we provide the first line of evidence that circZBTB46 is an important oncogenic circRNA as well as a diagnostic or prognostic biomarker for AML. CircZBTB46 exerts a critical role in promoting the expression of SCD to protect AML cells from ferroptotic cell death. Importantly, our findings may offer a potential therapeutic target, circZBTB46, to broaden treatment options for human AML, especially concerning the use of combined treatment with ferroptosis inducers. ABSTRACT: Circular RNAs (circRNAs) have been shown to be closely linked to the tumorigenesis and treatment response of hematological malignancies. However, the biological functions and clinical implications of circRNAs in acute myeloid leukemia (AML) remain largely unknown. CircRNA microarray datasets were analyzed to screen differentially expressed circRNAs in AML patients. It was found that circZBTB46 was significantly upregulated in AML patients and AML cells. Moreover, the expression of circZBTB46 was associated with the stages of AML patients and showed high sensitivity and specificity for diagnosing AML. Silencing of circZBTB46 inhibited AML cell proliferation and induced cell cycle arrest. Importantly, the depletion of circZBTB46 notably increased ferroptosis and enhanced RSL3-induced ferroptosis in AML cells. Mechanistically, circZBTB46 upregulated the expression of stearoyl-CoA desaturase 1 (SCD) possibly by acting as a miRNA sponge. Finally, the circZBTB46 knockdown repressed the tumor growth of AML in vivo. In conclusion, circZBTB46 protects AML cells from ferroptosis and promotes the proliferation by upregulating SCD, thus suggesting that circZBTB46 may be a potential therapeutic target for AML.