Protocol to identify covalent inhibitors targeting RhoA Cys16

Area of Science:

• Biochemistry
• Chemical Biology
• Oncology

Background:

• Ras homolog family member A (RhoA) is a crucial signaling protein implicated in various cancers.
• Despite its therapeutic importance, RhoA has been considered undruggable due to a lack of effective targeted inhibitors.

Purpose of the Study:

• To present a novel protocol for identifying covalent inhibitors targeting the RhoA Cys16 residue.
• To establish a method for validating compound engagement and assessing downstream signaling effects in cancer models.

Main Methods:

• Activity-based protein profiling (ABPP) for initial lead compound identification.
• Mass spectrometry and chemical biology assays for validation of target engagement.
• In vitro and in vivo experiments using cancer cell lines and mouse colorectal cancer (CRC) models to evaluate compound efficacy.

Main Results:

• Successful identification of lead compounds capable of covalently targeting RhoA Cys16.
• Demonstration of target engagement and downstream signaling modulation by the identified inhibitors.
• Validation of the protocol's utility in preclinical cancer models, including CRC.

Conclusions:

• The developed protocol provides a viable strategy for discovering covalent inhibitors against RhoA.
• This approach opens new avenues for targeting RhoA in cancer therapy, addressing a previously undruggable target.
• The findings support the potential of covalent RhoA inhibitors in treating cancers like colorectal cancer.