Isoliensinine Suppresses Colorectal Tumorigenesis by Targeting PPP2R1A to Activate AMPK Signaling Pathway

Abstract Colorectal cancer, characterized by its invasive behavior, frequent recurrence, and limited responsiveness to standard treatment, necessitate the advancement of innovative therapeutic approaches. Isoliensinine (ISO), a natural bisbenzylisoquinoline alkaloid, has demonstrated broad antitumor activity. However, its efficacy and underlying mechanisms in colorectal cancer therapy remain unclear and require further investigation. In our study, ISO demonstrates robust anti-colorectal cancer activity in both in vitro and in vivo. Through limited proteolysis-mass spectrometry (Lip-MS) screening, PPP2R1A was identified as a direct binding target of ISO, which was validated by bio-layer interferometry assays. Molecular dynamics simulations delineated the specific binding mode between ISO and PPP2R1A. Genetic knockdown of PPP2R1A attenuated colorectal cancer proliferation and partially abolished the antitumor effects of ISO. Integrated proteomic and phosphoproteomic analyses further revealed that ISO activates the AMPK signaling pathway following binding PPP2R1A. These results collectively establish ISO as a promising therapeutic agent for colorectal cancer treatment.