KLF11 promotes the proliferation of breast cancer cells by inhibiting p53-MDM2 signaling.

Abnormal Krüppel-like factor 11 (KLF11) expression is frequently found in tumor tissues and is associated with cancer prognosis, but its biological functions and corresponding mechanisms remain elusive. Here, we demonstrated that KLF11 functions as an oncoprotein to promote tumor proliferation in breast cancer cells. Mechanistically, at the transcription level, KLF11 decreased TP53 mRNA expression. Notably, KLF11 also interacted with and stabilized MDM2 through inhibiting MDM2 ubiquitination and subsequent degradation. This increase in MDM2 in turn accelerated the ubiquitin-mediated proteolysis of p53, leading to the reduced expression of p53 and its target genes, including CDKN1A, BAX, and NOXA1. Accordingly, data from animals further confirmed that KLF11 significantly upregulated the growth of breast cancer cells and was inversely correlated with p53 expression. Taken together, our findings reveal a novel mechanism for breast cancer progression in which the function of the tumor suppressor p53 is dramatically weakened.