Uterine fibroids (or leiomyomas) are highly prevalent benign tumors in women of reproductive age and are associated with abnormal uterine bleeding, pelvic pain, and infertility. Fibroid tumors are characterized by excessive extracellular matrix deposition and increased tissue stiffness, however the functional impact of this mechanical property in regulating fibroid cell behavior remains poorly understood. Uterine fibroids feature and increased number of senescent cells accompanied by profibrotic and inflammatory signaling but their contribution to fibroid growth is not fully understood. We observed that mechanical stiffness promoted senescence and fibrotic phenotypes in uterine fibroid cells. Fibroid cells cultured on stiff (⁓ 3 GPa) compared to soft (930 kPa) substrates exhibited elevated expression of senescence markers, including p16 and p21, as well as increased levels of fibrosis associated proteins such as fibronectin, PAI1, and α-SMA. Mechanistically, we identified Src and β-catenin as key regulators of this phenotype. Furthermore, the senolytic Src inhibitor dasatinib reduced senescence and fibrosis markers and attenuated β-catenin activity, suggesting that Src acts upstream of β-catenin in this context. Inhibition of β-catenin using ICG001 or PRI724 suppressed senescence and fibrosis markers and reduced downstream targets including CTGF and cyclin D1. These findings reveal a mechanistic link between mechanical stiffness, cellular senescence, and fibrosis in uterine fibroids, and identify Src and β-catenin as potential therapeutic targets.
