Opportunity
The Hippo signaling pathway is a highly conserved cellular pathway crucial for regulating tissue growth, homeostasis, and regeneration. Yes-associated protein (YAP), a key transcriptional co-activator downstream of the Hippo pathway, plays a pivotal role in the initiation, progression, and metastasis of various cancers, including breast cancer. YAP functions by binding to transcription factors like TEAD to activate downstream oncogenic gene expression. Its overexpression is frequently observed in multiple tumor types, and its inhibition has been shown to suppress tumorigenesis and promote apoptosis, making it a promising therapeutic target. However, YAP has long been considered a challenging, "undruggable" target due to its lack of well-defined binding pockets for small molecules and its large protein-protein interaction interfaces, which are difficult to selectively disrupt with conventional inhibitors. Existing strategies, such as molecules like Platanic acid that aim to block the YAP/TEAD interaction, have shown limited inhibitory activity and anti-tumor efficacy. Currently, there are no clinically approved drugs that directly target YAP. This significant unmet medical need for effective YAP-targeting therapies, particularly for cancers like breast cancer where YAP dysregulation is prominent, creates a substantial opportunity for developing novel agents with alternative mechanisms of action.
Technology
This patent discloses a novel class of compounds designed as YAP degraders, representing a innovative therapeutic strategy. The core technology involves bifunctional small molecules with a specific structure (Formula I) that can selectively induce the degradation of the YAP protein within cells. These compounds are proteolysis-targeting chimeras (PROTACs) or related degraders, conceptually comprising two key moieties linked by a flexible linker. One moiety (derived from a structure related to known YAP binders or inhibitors) is responsible for binding to the target YAP protein. The other moiety is a ligand (e.g., derived from a cereblon E3 ligase-binding molecule like a derivative of thalidomide/pomalidomide, as suggested by the 2,6-dioxopiperidine structure in the examples) that recruits the cellular ubiquitin-proteasome system. The linker, which can be a C3-C10 saturated alkylene or a C6-C10 alkylene containing 1-5 ether (C-O-C) structures, connects these two parts and is critical for optimal orientation and degradation efficiency. Upon administration, the compound simultaneously binds to YAP and an E3 ubiquitin ligase, bringing them into proximity. This leads to the polyubiquitination of YAP, marking it for recognition and subsequent degradation by the proteasome. This direct degradation mechanism effectively reduces intracellular YAP protein levels, thereby inhibiting its oncogenic transcriptional activity. The patent provides detailed synthetic routes, exemplified by compounds YD-1 to YD-5, starting from precursors like betulinic acid and linker-attached intermediates.
Advantages
- Offers a novel mechanism of action by directly degrading the YAP protein, rather than merely inhibiting its activity.
- Potentially overcomes the "undruggability" of YAP by targeting it for destruction via the ubiquitin-proteasome system.
- Demonstrated potent anti-proliferative effects against human breast cancer cells (MDA-MB-231), with compound YD-5 showing an IC50 of 12.5 μM, significantly better than the precursor compound PA (IC50 45.6 μM).
- Confirmed ability to degrade YAP protein in cancer cells, with compound YD-5 achieving approximately 60% degradation efficiency in cellular assays.
- Provides a series of compounds with modifiable linkers, allowing for optimization of pharmacokinetic properties and degradation potency.
- The preparation method is clearly outlined and exemplified, facilitating production.
Applications
- Primary application is in the preparation of pharmaceutical drugs for treating diseases associated with aberrant YAP expression or activity.
- Specifically targeted for cancer therapy, with a highlighted focus on breast cancer treatment.
- Potential application in other cancers where YAP plays a role, such as liver, lung, and colorectal cancers.
- Could be formulated into various drug compositions (e.g., tablets, capsules, injectables) with pharmaceutically acceptable carriers and excipients.
- Provides a research tool for studying YAP biology and validating YAP as a therapeutic target in various disease models.
