KCTD15 Enhances Stem Cell‐Like Properties and Promotes Triple‐Negative Breast Cancer Progression Through KLF4 /β‐Catenin Signaling

ABSTRACT Triple‐negative breast cancer (TNBC) remains an aggressive malignancy with limited therapeutic options and poor prognosis, underscoring the critical need for novel therapeutic targets. This investigation elucidates the functional role of the potassium channel tetramerization domain 15 (KCTD15) in TNBC progression, providing mechanistic insights into its potential as a therapeutic target for this challenging disease. KCTD15 exhibited high expression in TNBC tissues, correlating with advanced grade and unfavorable prognosis. Functionally, KCTD15 knockdown in TNBC cell lines (BT‐549/MDA‐MB‐231) markedly suppressed cellular proliferation, migration, and cancer stem cell properties, while concomitantly enhancing apoptosis. Mechanistically, KCTD15 directly interacted with KLF4, facilitating its nuclear translocation and subsequent activation of the β‐catenin signaling cascade. Notably, KLF4 knockdown abrogated KCTD15‐mediated stemness maintenance and β‐catenin pathway activation. In vivo, KCTD15 silencing reduced xenograft tumor growth and downregulated Ki67, KLF4, and β‐catenin protein expression in tumor tissues, confirming its oncogenic role through the KLF4/β‐catenin axis. Our findings establish KCTD15 as a pivotal regulator of TNBC stemness through modulation of the KLF4/β‐catenin signaling axis. These results provide a robust preclinical rationale for developing therapeutic strategies targeting this molecular axis in TNBC management.