MARCH1, transcriptionally regulated by POU2F2, facilitates acute myeloid leukemia progression via inducing MYCT1 degradation.

Acute myeloid leukemia (AML) is a heterogeneous clonal disease. Membrane-associated ring-CH type finger 1 (MARCH1), a membrane-anchored E3 ubiquitin ligase, is highly expressed in AML. However, its role in AML remains unclear. Our study showed that MARCH1 expression was strongly associated with FAB classifications and the survival of patients with AML. Gain-of-function and loss-of-function experiments showed that MARCH1 promoted the proliferation of AML cells and inhibited apoptosis and differentiation. In vivo, MARCH1 knockdown inhibited the infiltration of AML cells, resulting in prolonged survival of AML mice. In order to illustrate what cause the high expression of MARCH1, we analyzed the promoter region of MARCH1 and found that POU2F2, a transcription factor with high levels in AML, positively regulated the transcription of MARCH1. Finally, we demonstrated that MARCH1 interacted with MYCT1, a candidate tumor suppressor, and accelerated its ubiquitination and degradation. Remarkably, MYCT1 knockdown abolished the inhibitory effects of MARCH1 knockdown on AML cell growth. Our findings indicate that MARCH1, whose transcription is positively modulated by POU2F2, facilitates the malignant behaviors of AML cells through interacting with MYCT1 and accelerating its ubiquitination and degradation. The results implied that targeting MARCH1 might be a promising therapeutic strategy for AML.