Effects of linsitinib on M22 and IGF-1-treated 3D spheroids of human orbital fibroblasts

This study investigates the role of IGF-1 receptor inhibition in Graves’ orbitopathy (GO) using three-dimensional (3D) spheroids derived from human orbital fibroblasts obtained from patients with and without GO. Treatment with IGF-1 and the stimulatory TSH receptor antibody M22 significantly increased mitochondrial and glycolytic activity and induced marked stiffening of 3D spheroids, accompanied by up-regulation of extracellular matrix proteins and profibrotic markers. Linsitinib, a selective IGF-1R/IR inhibitor, effectively suppressed M22-induced increases in spheroid stiffness despite having minimal effects on spheroid size. Changes in stiffness closely correlated with altered expression of collagens, fibronectin, lysyl oxidase, connective tissue growth factor, and matrix metalloproteinases, indicating mechanically driven fibrogenesis. These findings demonstrate that mechanical phenotyping of 3D orbital fibroblast spheroids provides a sensitive in vitro platform for studying GO pathogenesis and evaluating antifibrotic therapeutic strategies. :contentReference[oaicite:1]{index=1}