NSC 146109 hydrochloride, also known as XI-011, is primarily utilized in biomedical research for its role as a potent inhibitor of the Notch signaling pathway. This pathway is crucial in regulating cell differentiation, proliferation, and apoptosis, making XI-011 a valuable tool in studying cancer biology. Researchers employ it to investigate the effects of Notch pathway inhibition in various cancer models, particularly in cancers where Notch signaling is dysregulated, such as breast cancer, leukemia, and glioblastoma. By suppressing Notch activity, XI-011 helps in understanding the pathway's contribution to tumor growth and progression, and it is also explored for its potential therapeutic applications in cancer treatment. Additionally, it is used in developmental biology studies to examine the role of Notch signaling in tissue development and regeneration.