mRNA splicing inhibitor; decreases splicing capacity up to 75% in vitro. Directly targets splicesome-associated 130 (SAP130), inhibits splicing factor 3B subunit (SF3B1) and impairs U2 small nuclear ribonucleoprotein (U2 snRNP) interaction with pre-mRNA. Arrests cell cycle in G1 and G2/M phases. Displays antitumor activity against gastric cancer cells (IC50 values are 1.6-4.9 nM). Cell permeable and active in vivo. Purity 95%. MW (observed): 536.7