Abstract 64P
Background
Metabolic reprogramming is a key hallmark of cancer. Tumour cells switch from normal respiratory pathway to aerobic glycolysis, known as ‘Warburg effect’. Pyruvate kinase M2 (PKM2), an enzyme that governs the final step of glycolysis, contributes to this metabolic shift and tumorigenesis by forming a dimer with low pyruvate kinase activity. Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortality worldwide. PKM2 is overexpressed in HCC and associated with poor prognosis. Hence, activating PKM2 can be a potential therapeutic approach for HCC treatment. To achieve specific targeting of PKM2, covalent ligands are promising compounds as they have been clinically used to target even undruggable proteins through the formation of covalent bonds with the proteins to achieve stronger binding affinity. In this study, we have developed a covalent activator of PKM2 to treat HCC.
Methods
An in-house library of cysteine-targeting compounds was screened using activity-based protein profiling (ABPP) and pyruvate kinase activity assay. ABPP is a chemoproteomics technique for studying reactivity of amino acids on proteins, and can be applied for protein target identification of cysteine-targeting compounds in HCC cells. While pyruvate kinase activity assay can identify compounds that activates PKM2, by combining the 2 screening results, lead compounds that bound and activated PKM2 were found.
Results
2J1 was identified as the lead compound targeting PKM2. It could bind to PKM2 at nanomolar range in vitro. It showed little off-target binding in LC-MS/MS target profiling. It also increased pyruvate kinase activity. It interrupted the dynamics of PKM2 dimer and tetramer by promoting tetramer formation and inhibiting PKM2 nuclear translocation in HCC cells. This led to significant increase of reactive oxygen species (ROS) generation, and reduction in stem-like property. 2J1 exhibited anti-tumour activity in mouse HCC models.
Conclusions
Here we report a lead compound, 2J1, that targets and activates PKM2 in HCC. It showed good potency and hijacked the equilibrium between PKM2 dimer and tetramer. 2J1 is a potential covalent ligand to treat HCC.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
C.Y-S. Chung.
Funding
The University of Hong Kong.
Disclosure
All authors have declared no conflicts of interest.