PRMT5-IN-31 (Compound 3m), a selective PRMT5 inhibitor (IC50: 0.31 μM), increases hnRNP E1 protein levels by occupying the substrate site of PRMT5 and establishing key interactions with amino acid residues. It exhibits antiproliferative properties against A549 cells through induction of apoptosis and inhibition of cell migration, while demonstrating high metabolic stability in human liver microsomes (T1/2: 132.4 min) [1].