Deciphering the TCF19/miR-199a-5p/SP1/LOXL2 pathway: Implications for breast cancer metastasis and epithelial-mesenchymal transition.

Globally, breast cancer (BC) is the predominant malignancy with a significant death rate due to metastasis. The epithelial-mesenchymal transition (EMT) is a fundamental initiator for metastatic progression. Through advanced computational strategies, TCF19 was identified as a critical EMT-associated gene with diagnostic and prognostic significance in BC, based on a novel EMT score. Molecular details and the pro-EMT impact of the TCF19/miR-199a-5p/SP1/LOXL2 axis were explored in BC cell lines through in vitro validations, and the oncogenic and metastatic potential of TCF19 and LOXL2 were investigated using subcutaneous and tail-vein models. Additionally, BC-specific enrichment of TCF19 and LOXL2 was measured using a distribution landscape driven by diverse genomic analysis techniques. Molecular pathways revealed that TCF19-induced LOXL2 amplification facilitated migratory, invasive, and EMT activities of BC cells in vitro, and promoted the growth and metastatic establishment of xenografts in vivo. TCF19 decreases the expression of miR-199a-5p and alters the nuclear dynamics of SP1, modulating SP1's affinity for the LOXL2 promoter, leading to increased LOXL2 expression and more malignant characteristics in BC cells. These findings unveil a novel EMT-inducing pathway, the TCF19/miR-199a-5P/SP1/LOXL2 axis, highlighting the pivotal role of TCF19 and suggesting potential for novel therapeutic approaches for more focused BC interventions.