YAP-TEAD Inhibitor 1

The Hippo signalling pathway has emerged as a major player in many aspects of liver biology, such as development, cell fate determination, homeostatic function and regeneration from injury. The regulation of Hippo signalling is complex, with activation of the pathway by diverse upstream inputs including signals from cellular adhesion, mechanotransduction and crosstalk with other signalling pathways. Pathological activation of the downstream transcriptional co-activators yes-associated protein 1 (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ, encoded by WWTR1), which are negatively regulated by Hippo signalling, has been implicated in multiple aspects of chronic liver disease, such as the development of liver fibrosis and tumorigenesis. Thus, development of pharmacological inhibitors of YAP-TAZ signalling has been an area of great interest. In this Review, we summarize the diverse roles of Hippo signalling in liver biology and highlight areas where outstanding questions remain to be investigated. Greater understanding of the mechanisms of Hippo signalling in liver function should help facilitate the development of novel therapies for the treatment of liver disease.

Eradicating tumor dormancy that develops following epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) treatment of EGFR-mutant non-small cell lung cancer, is an attractive therapeutic strategy but the mechanisms governing this process are poorly understood. Blockade of ERK1/2 reactivation following EGFR TKI treatment by combined EGFR/MEK inhibition uncovers cells that survive by entering a senescence-like dormant state characterized by high YAP/TEAD activity. YAP/TEAD engage the epithelial-to-mesenchymal transition transcription factor SLUG to directly repress pro-apoptotic BMF, limiting drug-induced apoptosis. Pharmacological co-inhibition of YAP and TEAD, or genetic deletion of YAP1, all deplete dormant cells by enhancing EGFR/MEK inhibition-induced apoptosis. Enhancing the initial efficacy of targeted therapies could ultimately lead to prolonged treatment responses in cancer patients.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive human malignancies. The Yes-associated protein-1 (YAP) plays a critical role in cell proliferation, apoptosis and angiogenesis. Verteporfin is a photosensitizer used in photodynamic therapy and also a small molecular inhibitor of the Hippo-YAP pathway. However, little is known about whether verteporfin could inhibit YAP activity in PDAC cells. Our present results showed that verteporfin suppressed the proliferation of human PDAC PANC-1 and SW1990 cells by arresting cells at the G1 phase, and inducing apoptosis in dose- and time-dependent manners. Verteporfin also inhibited the tumor growth on the PDAC xenograft model. Treatment with verteporfin led to downregulation of cyclinD1 and cyclinE1, modulation of Bcl-2 family proteins and activation of PARP. In addition, verteporfin exhibited an inhibitory effect on angiogenesis and vasculogenic mimicry via suppressing Ang2, MMP2, VE-cadherin, and α-SMA expression in vitro and in vivo. Mechanism studies demonstrated that verteporfin impaired YAP and TEAD interaction to suppress the expression of targeted genes. Our results provide a foundation for repurposing verteporfin as a promising anti-tumor drug in the treatment of pancreatic cancer by targeting the Hippo pathway.