Interplay between Leptin and Stearoyl-CoA Desaturase 1 in Estrogen Receptor–Positive Breast Cancer Cells

Obesity, a global health challenge, contributes to various cancers, including breast cancer. Complex metabolic dysregulation marks the development of both breast cancer and obesity. Here, the interplay between the obesity-derived adipokine leptin (LEP) and stearoyl-CoA desaturase 1 (SCD), a critical enzyme in fatty acid (FA) metabolism, was explored. While Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database analysis reported a significant protein-protein interaction between LEP and SCD, functional processing of the differentially expressed genes in LEP-treated breast cancer cells revealed a critical involvement of SCD in the interactome of deregulated proteins. Kaplan-Meier analyses linked LEP/SCD expression to poorer recurrence-free survival in patients with estrogen receptor α luminal A-like breast cancer. Functional studies demonstrated that LEP up-regulated SCD expression in luminal A-like breast cancer cells through LEP receptor-mediated signaling. Lipidomic profiling showed that SCD inhibition using MF-438 reduced LEP-induced FA desaturation, characterized by a shift from saturated to monounsaturated FAs. SCD inhibition also abolished the LEP-mediated mitochondrial respiration and ATP production. Additionally, LEP-induced oncogenic features, including enhanced growth and motility, were counteracted by pharmacologic/genetic SCD blockade, confirming SCD's role in leptin's protumorigenic effects. This study highlights the LEP-SCD axis as a driver of metabolic/functional alterations in estrogen receptor α-positive breast cancer, providing insights into the obesity-breast cancer link and identifying potential therapeutic targets (ie, SCD) to counter obesity-driven cancer progression.