Significance of LIF/LIFR Signaling in the Progression of Obesity-Driven Triple-Negative Breast Cancer.

Simple Summary: The obesity epidemic in the USA is increasing the risk of aggressive triple-negative breast cancer (TNBC) in obese women. This study investigated the potential impact of obesity on the advancement of TNBC by amplifying leukemia inhibitory factor receptor (LIFR) signaling. We tested the effects of LIFR inhibition using EC359 on TNBC cells in obesity conditions. The obesity environment increased TNBC cell growth and invasion, and treatment with EC359 effectively reduced these effects. Using TNBC cells, patient-derived organoids, and mouse models, we showed that EC359 can inhibit obesity-linked TNBC progression. Collectively, our results suggest targeting LIFR signaling as a potential treatment for obesity-related TNBC. American women with obesity have an increased incidence of triple-negative breast cancer (TNBC). The impact of obesity conditions on the tumor microenvironment is suspected to accelerate TNBC progression; however, the specific mechanism(s) remains elusive. This study explores the hypothesis that obesity upregulates leukemia inhibitory factor receptor (LIFR) oncogenic signaling in TNBC and assesses the efficacy of LIFR inhibition with EC359 in blocking TNBC progression. TNBC cell lines were co-cultured with human primary adipocytes, or adipocyte-conditioned medium, and treated with EC359. The effects of adiposity were measured using cell viability, colony formation, and invasion assays. Mechanistic studies utilized RNA-Seq, Western blotting, RT-qPCR, and reporter gene assays. The therapeutic potential of EC359 was tested using xenograft and patient-derived organoid (PDO) models. The results showed that adipose conditions increased TNBC cell proliferation and invasion, and these effects correlated with enhanced LIFR signaling. Accordingly, EC359 treatment reduced cell viability, colony formation, and invasion under adipose conditions and blocked adipose-mediated organoid growth and TNBC xenograft tumor growth. RNA-Seq analysis identified critical pathways modulated by LIF/LIFR signaling in diet-induced obesity mouse models. These findings suggest that adiposity contributes to TNBC progression via the activation of the LIF/LIFR pathway, and LIFR inhibition with EC359 represents a promising therapeutic approach for obesity-associated TNBC. [ABSTRACT FROM AUTHOR]