RNA -methyladenosine Reader YTHDC1 is Essential for TGF-beta-mediated Metastasis of Triple Negative Breast Cancer

Methods: and models were employed to determine the pathological function of in TNBC metastasis. To identify YTHDC1 target RNAs, we conducted RNA-seq, mA-seq, and RIP-seq, followed by integrative data analysis and validation assays.

Results: By analyzing The Cancer Genome Atlas (TCGA) dataset, we found that elevated expression of is positively correlated with poor prognosis in breast cancer patients. Using a mammary fat pad mouse model of TNBC, significantly promoted lung metastasis of TNBC cells. Through multiple transcriptome-wide sequencing and integrative data analysis, we revealed dysregulation of metastasis-related pathways following YTHDC1 depletion and identified SMAD3 as a bona fide YTHDC1 target RNA. Depletion of YTHDC1 caused nuclear retention of mRNA, leading to lower SMAD3 protein levels. Loss of YTHDC1 led to impaired TGF-β-induced gene expression, leading to inhibition of epithelial-mesenchymal transition (EMT) and suppressed TNBC cell migration and invasion. SMAD3 overexpression was able to restore the response to TGF-β in YTHDC1 depleted TNBC cells. Furthermore, we demonstrated that the oncogenic role of YTHDC1 is mediated through its recognition of mA as mA-binding defective mutants of YTHDC1 were unable to rescue the impaired cell migration and invasion of YTHDC1 knockout TNBC cells.

Conclusions: We show that YTHDC1 plays a critical oncogenic role in TNBC metastasis through promoting the nuclear export and expression of to augment the TGF-β signaling cascade. Overall, our study demonstrates that YTHDC1 is vital for TNBC progression by enhancing TNBC cell survival and TGF-β-mediated EMT via SMAD3 to enable the formation of distant metastasis and highlights the therapeutic potential of targeting the YTHDC1/mA/SMAD3 axis for TNBC treatment.