FBXO24 Suppresses Breast Cancer Tumorigenesis by Targeting LSD1 for Ubiquitination

Lysine-specific demethylase 1 (LSD1), a critical chromatin modulator, functions as an oncogene by demethylation of H3K4me1/2. The stability of LSD1 is governed by a complex and intricate process involving ubiquitination and deubiquitination. Several deubiquitinases preserve LSD1 protein levels. However, the precise mechanism underlying the degradation of LSD1, which could mitigate its oncogenic function, remains unknown. To gain a better understanding of LSD1 degradation, we conducted an unbiased siRNA screening targeting all the human SCF family E3 ligases. Our screening identified FBXO24 as a genuine E3 ligase that ubiquitinates and degrades LSD1. As a result, FBXO24 inhibits LSD1-induced tumorigenesis and functions as a tumor suppressor in breast cancer cells. Moreover, FBXO24 exhibits an inverse correlation with LSD1 and is associated with a favorable prognosis in breast cancer patient samples. Taken together, our study uncovers the significant role of FBXO24 in impeding breast tumor progression by targeting LSD1 for degradation.