DCAF13 promotes triple-negative breast cancer metastasis by mediating DTX3 mRNA degradation.

DCAF13 is firstly identified as a substrate receptor of CUL4-DDB1 E3 ligase complex. This study disclosed that DCAF13 acted as a novel RNA binding protein (RBP) that contributed to triple-negative breast cancer (TNBC) metastasis. Clinical data obtained from TCGA and our collection showed that DCAF13 was closely correlated with poor clinicopathological characteristics and overall survival, which indicated DCAF13 may serve as a diagnostic marker for TNBC metastasis. Functionally, DCAF13 overexpression or suppression was sufficient to enhance or decrease breast cancer cell migration and invasion. Mechanistically, DCAF13 functioned as an RBP by binding with the AU-rich element (ARE) of DTX3 mRNA 3'UTR to accelerate its degradation. Moreover, we identified that DTX3 promoted the ubiquitination and degradation of NOTCH4. Finally, increased DCAF13 expression led to post-transcriptional decay of DTX3 mRNA and consequently activated of NOTCH4 signaling pathway in TNBC. In conclusion, these results identified that DCAF13 as a diagnostic marker and therapeutic target for TNBC treatment. Abbreviation: DCAF13: DDB1 and CUL4-associated factor 13; DDB1: DNA-binding protein 1; CUL4: Cullin 4; CRL4, Cullin-ring finger ligase 4; RBP: RNA binding protein; TNBC: triple-negative breast cancer; ARE: AU-rich element; DTX3: Deltex E3 ubiquitin ligase 3; HER2: human epidermal growth factor receptor 2; ER: estrogen receptor; PR: progesterone receptor; PTEN: phosphatase and tensin homolog deleted on chromosome 10; EMT: epithelial-mesenchymal transition.