EBF3 transcriptionally activates ACADL to block the Hippo/YAP signaling pathway and inhibits breast cancer progression.

[OBJECTIVE] Breast cancer (BC) is the chief cause of malignancy-related deaths in women. This paper investigates how the EBF3-ACADL axis inhibits BC progression through Hippo/YAP signaling.

[METHODS] The differentially expressed gene ACADL in BC was screened by the bioinformatics databases, and ACADL expression in BC tumors and cells was verified by immunohistochemistry, RT-qPCR, and western blot analysis. BC cells were infected with an overexpressing-ACADL lentivirus to examine the effect of ACADL on BC cell growth. The in vivo impact of ACADL was investigated by constructing a xenograft tumor model. Cells were treated with XMU-MP-1, an inhibitor of MST1/2 kinase, to study the influence of ACADL on BC progression through the Hippo/YAP pathway. The upstream mechanism of abnormally elevated ACADL expression was analyzed by bioinformatics, and EBF3 expression in BC tumors and cells was verified. Regulatory assays were performed to confirm the binding relationship between ACADL and EBF3.

[RESULTS] ACADL and EBF3 were poorly expressed in BC tissues and cell lines. ACADL overexpression blocked p-YAP (Ser127), nuclear YAP localization, and canonical target genes (CTGF, CYR61, and ANKRD1), thereby suppressing BC cell growth and xenograft tumor development. XMU-MP-1 reversed the suppressive effect of ACADL overexpression on BC progression. EBF3 transcriptionally activated ACADL expression by binding to its promoter. EBF3 overexpression suppressed the malignant behavior of BC cells and xenograft tumor development in mice, which was reversed by ACADL knockdown.

[CONCLUSION] EBF3 transcriptionally activates ACADL and blocks the Hippo/YAP pathway to inhibit BC progression.