The palmitoyltransferase ZDHHC21 regulates oxidative phosphorylation to induce differentiation block and stemness in AML

•The palmitoyltransferase ZDHHC21 is the key factor that regulates OXPHOS hyperactivity in AML cells as well as LSCs.•ZDHHC21 inhibition facilitates the therapeutic differentiation of AML cells and eradicates AML blasts in relapsed/refractory leukemia. [Display omitted] Acute myeloid leukemia (AML) is an aggressive hematological malignancy. Nearly 50% of patients who receive the most intensive treatment inevitably experience disease relapse, likely resulting from the persistence of drug-resistant leukemia stem cells (LSCs). AML cells, especially LSCs, are highly dependent on mitochondrial oxidative phosphorylation (OXPHOS) for survival, but the mechanism involved in OXPHOS hyperactivity is unclear, and a noncytotoxic strategy to inhibit OXPHOS is lacking. To our knowledge, this study is the first to demonstrate that ZDHHC21 palmitoyltransferase serves as a key regulator of OXPHOS hyperactivity in AML cells. The depletion/inhibition of ZDHHC21 effectively induced myeloid differentiation and weakened stemness potential by inhibiting OXPHOS in AML cells. Interestingly, FMS-like tyrosine kinase-3 internal tandem duplication (FLT3-ITD)–mutated AML cells expressed significantly higher levels of ZDHHC21 and exhibited better sensitivity to ZDHHC21 inhibition. Mechanistically, ZDHHC21 specifically catalyzed the palmitoylation of mitochondrial adenylate kinase 2 (AK2) and further activated OXPHOS in leukemic blasts. Inhibition of ZDHHC21 arrested the in vivo growth of AML cells and extended the survival of mice inoculated with AML cell lines and patient derived xenograft AML blasts. Moreover, targeting ZDHHC21 to suppress OXPHOS markedly eradicated AML blasts and enhanced chemotherapy efficacy in relapsed/refractory leukemia. Together, these findings not only uncover a new biological function of palmitoyltransferase ZDHHC21 in regulating AML OXPHOS but also indicate that ZDHHC21 inhibition is a promising therapeutic regimen for patients with AML, especially relapsed/refractory leukemia. Shao and colleagues reveal that a palmitoyltransferase, zinc finger DHHC-type containing 21 (ZDHHC21), regulates oxidative phosphorylation and is essential for a subset of acute myeloid leukemia (AML) cells in preclinical models. The authors’ work maps how palmitoylation of protein substrates by ZDHHC21 influences mitochondrial function and highlights ZDHHC21 as a potential druggable therapeutic target in AML.