Liquiritigenin exhibits antitumour action in pituitary adenoma cells via Ras/ERKs and ROS-dependent mitochondrial signalling pathways

Objective The purpose of this study was to investigate antitumour effects of liquiritigenin (LQ) on pituitary adenoma in in‐vitro and in‐vivo models. Methods The effects of LQ on cell viability, apoptosis rate, mitochondrial membrane potential (MMP), intracellular reactive oxygen species (ROS) level and various apoptosis‐related mediators were examined in MMQ and GH3 cells that are derived from rat pituitary adenoma. Antitumour effect of LQ was also examined in the mouse model of GH3‐xenografted tumour. Key findings LQ inhibited cell viability, caused G1 phase arrest and initiated apoptosis in both MMQ and GH3 cells. LQ dissipated MMP, increased intracellular ROS level and cytosol cytochrome C, and reduced the expression of Ras, B‐cell lymphoma 2 and B‐cell lymphoma‐extra large. LQ also inhibited the activation of extracellular signalling‐regulated kinases (ERKs) and the translocation of from cytoplasm to nucleus. LQ markedly reduced tumour size without affecting bodyweight in mice with GH3 cells xenograft. Conclusions LQ effectively inhibits pituitary adenoma tumour growth and induces cell apoptotic death mainly via Ras/ERKs and ROS‐dependent mitochondrial pathways, suggesting that LQ is a potential suppressor of pituitary adenoma.