Abstract

This study describes the identification and target deconvolution of novel small molecule inhibitors of oncogenic YAP1/TAZ activity with potent anti-tumor activity in vivo. A high-throughput screen of 3.8 million compounds was conducted using a cellular YAP1/TAZ reporter assay. Target deconvolution studies, including cellular thermal shift assays and CRISPR/Cas9-KO screens identified PGGT1B, a subunit of the geranylgeranyltransferaseI (GGTaseI) complex, as the direct target of YAP1/TAZ pathway inhibitors. The novel small molecule inhibitors blocked the activation of Rho-GTPases at the cell membrane, leading to subsequent inactivation of YAP1/TAZ. YAP1/TAZ target genes AXL/CAV1 identified as selection biomarker candidates based on cell line response profiles. Multi-parameter optimization resulted in BAY 593, an in vivo probe with favorable in vivo PK properties, which demonstrated potent anti-tumor activity and blockade of YAP1/TAZ signaling in vivo.