Discovery of the U2AF1-UHM Inhibitor That Possesses Anti-Leukemia Activity In Vitro

Area of Science:

• Molecular Biology
• Cancer Biology
• Drug Discovery

Background:

• U2AF1 and U2AF2 form a heterodimer essential for RNA splicing by defining the 3' splice site.
• Mutations in U2AF1 are linked to splicing dysregulation and are common in hematological neoplasms.
• No potent U2AF1 inhibitors have been previously reported.

Purpose of the Study:

• To develop a potent inhibitor targeting the U2 auxiliary homology motif (UHM) of U2AF1.
• To evaluate the anti-leukemia activity and cellular effects of the developed inhibitor.
• To establish a tool for investigating U2AF1 function and a lead for future drug optimization.

Main Methods:

• Development of AP232, a novel inhibitor targeting the UHM of U2AF1, based on SF153.
• In vitro assessment of AP232's inhibitory activity (IC50) against U2AF1 and selectivity against other UHM proteins.
• Evaluation of AP232's anti-leukemia effects, including cell cycle arrest, lysosome acidification, and autophagy inhibition in leukemia cell lines.

Main Results:

• AP232 demonstrated a 31-fold improvement in IC50 compared to SF153 against U2AF1.
• AP232 exhibited 3-24 fold selectivity against other UHM proteins.
• AP232 displayed anti-leukemia activity, particularly in cell lines with splicing factor mutations, and induced G2/M and G1 arrest, impaired lysosome acidification, and inhibited autophagy.

Conclusions:

• AP232 is a potent and selective inhibitor of U2AF1.
• AP232 exhibits anti-leukemia effects and modulates cellular processes like cell cycle, lysosome function, and autophagy.
• AP232 serves as a valuable tool for studying U2AF1 in cellular contexts and as a promising lead for developing novel therapeutics for hematological neoplasms.