Podocarpusflavone A Inhibits Multiple Myeloma Cells by Targeting the PI3K/AKT Pathway to Mediate c-Myc Downregulation and Activate the Intrinsic Apoptosis Pathway.

Abstract

Multiple myeloma (MM) is an incurable blood cancer driven by uncontrolled growth of malignant plasma cells. Current treatments rarely yield durable remissions. Podocarpusflavone A-a natural biflavonoid from Podocarpus plants-shows broad antitumor activity, yet its effects on MM are unknown. This study used an integrative approach combining in vitro functional assays with bioinformatic profiling to investigate the anti-myeloma activity of Podocarpusflavone A. CCK-8 assays showed that the compound potently inhibited U266 and RPMI-8226 MM cell viability, with IC₅₀ values of 8.87 μM and 17.49 μM, respectively. Flow cytometry and Western blot analyses showed that Podocarpusflavone A induces apoptosis in a dose-dependent manner, increasing Cleaved-Caspase3 and BAX while decreasing Bcl-2-revealing a key molecular mechanism for its therapeutic potential. Further bioinformatic analyses combined with rigorous Western blot validation showed that Podocarpusflavone A effectively targets and suppresses the PI3K/AKT pathway, thereby promoting the downregulation of the oncogenic effector c-Myc. Immunofluorescence assays revealed that this compound significantly increases intracellular ROS, induces DNA damage, and disrupts mitochondrial membrane potential. These findings reveal that Podocarpusflavone A induces apoptosis in MM cells by simultaneously inhibiting pro-survival signaling and activating the intrinsic, mitochondria-dependent apoptotic pathway. This is the first study to comprehensively identify its specific molecular targets in MM-offering a promising new strategy to overcome drug resistance and current clinical limitations.