Abstract 3408: The role of obesity in promoting the LIF/LIFR signaling in triple negative breast cancer
Authors: Randolph Lois , Sanchez Alondra Rodriguez , Blankenship Logan , Pratap Uday P. , Yang Xue , Panneerdoss Durga Meenakshi , Konda Swapna , Santhamma Bindu , Sareddy Gangadhara R. , Rao Manjeet K. , Kost Edward R. , Tekmal Rajeshwar R. , Nair Hareesh B. , Vadlamudi Ratna K. , Viswanadhapalli Suryavathi 
Published: April 2023

Abstract
Background: Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer (BC) that accounts for a disproportionate amount of BC mortality. The relationship(s) between obesity and the TNBC is crucial because the obesity prevalence in the USA is on the rise. Obese patients are generally diagnosed with large primary tumors, more lymph node metastases, and obesity effects on tumor microenvironment (TME) are suspected to accelerate the development of TNBC, but the exact mechanism(s) by which this occurs remain unknown. The goal of this study is to investigate the hypothesis that obesity enhances leukemia inhibitory factor receptor (LIFR) oncogenic signaling in TNBC and to test the utility of LIFR inhibitor in blocking obesity driven progression of TNBC.
Methods: Established TNBC cell lines were co-cultured with human primary adipocytes, incubated with adipocyte conditioned media, or exposed to high glucose (HG), then treated with the LIFR inhibitor EC359. Cell viability, colony formation, and invasion assays were used to analyze the impact of obesity on TNBC cells and to test utility of EC359. RT-qPCR, Western blotting, reporter gene assays, and RNA-seq analyses were used in the mechanistic studies. Xenografts and patient-derived organoid (PDO) models were used to evaluate the effectiveness of the EC359.
Results: The cell proliferation and invasion of TNBC cells were accelerated by adipocyte conditioned media or when exposed to HG. RNA-seq and RT-qPCR analysis revealed a correlation between elevated LIFR expression and downstream LIFR signaling, including STAT3, as well as the subsequent activation of STAT3 target genes. The cell viability, colony formation, and invasion of TNBC cells under HG and adipose conditions were all markedly decreased after treatment with LIFR inhibitor EC359. Results from Western blotting demonstrated that co-culture with adipocytes or incubation with HG dramatically increased LIFR downstream signaling in TNBC model cells, and that this signaling is effectively suppressed by EC359 therapy. In addition, administration of EC359 prevented organoid proliferation that was mediated by the adipose conditioned media. Importantly, co-implantation of adipocytes greatly increased the growth of the TNBC xenograft tumor; however, therapy with EC359 significantly reduced the growth of TNBC caused by adipocyte co-implantation.
Conclusions: Collectively, these findings suggest that obesity conditions promote the activation of LIF/LIFR pathway, which in turn enhances TNBC cell proliferation. The LIFR inhibitor EC359 may be employed as a new therapeutic drug to treat obesity driven TNBC and LIF/LIFR axis represents a potential therapeutic target for obesity driven TNBC.
Citation Format: Lois Randolph, Alondra Rodriguez Sanchez, Logan Blankenship, Uday P. Pratap, Xue Yang, Durga Meenakshi Panneerdoss, Swapna Konda, Bindu Santhamma, Gangadhara R. Sareddy, Manjeet K. Rao, Edward R. Kost, Rajeshwar R. Tekmal, Hareesh B. Nair, Ratna K. Vadlamudi, Suryavathi Viswanadhapalli. The role of obesity in promoting the LIF/LIFR signaling in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3408.