The Adipokine Visfatin Modulates Cancer Stem Cell Properties in Triple-Negative Breast Cancer

Obesity is a cancer progression risk factor; excessive adipocytes increase adipokine secretion. Visfatin, a novel adipokine highly expressed in cancer patients, is related to breast cancer risk. The modulation of nicotinamide adenine dinucleotide (NAD+) metabolism and the induction of a tumorigenic environment plays a vital role in cancer progression. Among cancer cell types, cancer stem-like cells (CSCs) with self-renewal and chemotherapy-resistance abilities could modulate tumor progression and cancer recurrence ability. In this study, we focused on visfatin's modulation effect on stemness-related properties using the high-malignancy breast cancer cell line MDA-MB-231 in in vitro and in vivo studies. Visfatin treatment significantly increased both the sphere number and sphere diameter and increased the protein expression of NANOG homeobox (NANOG), sex-determining region Y-box 2 (SOX2), and octamer-binding transcription factor 4 (OCT4), as well as SIRT1 protein levels. The serum angiogenesis marker VEGF and extracellular nicotinamide phosphoribosyl transferase (NAMPT, visfatin) were induced after visfatin treatment, increasing the stemness and angiogenesis environment, which were significantly reduced by the visfatin inhibitor FK866. Our results demonstrate that the visfatin-activated SIRT-SOX2 axis promotes triple-negative breast cancer stemness and enriches the tumorigenic microenvironment.