Inocutis levis Mycelial Extract WYS Exerts Anti-Proliferative and Pro-Apoptotic Effects on MCF-7 Cells via EGFR/MEK/ERK Modulation and G2/M Arrest

Inocutis levis (I. levis) is a rare edible and medicinal macrofungus with a traditional history of consumption as a dietary supplement and functional food raw material. However, the material basis and molecular mechanisms underlying its anti-breast cancer activity remain unclear. The present work aimed to systematically investigate the anti-proliferative activity of WYS, an active mycelial fraction isolated from I. levis, against MCF-7 breast cancer cells and to explore its underlying mechanisms. Firstly, 152 metabolites were putatively annotated in the WYS fraction via ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) combined with database matching. Through an integrated strategy combining network pharmacology and multi-algorithm machine learning screening, four core metabolites (dihydroartemisinin, cortisol, cinnamic acid, and guanosine) and five hub targets (CDK1, EGFR, TOP2A, FGF2, and KIT) were prioritized. Furthermore, 100 ns molecular dynamics simulations and molecular docking predicted favorable binding affinities between the core metabolites and their cognate target proteins and predicted that the anti-breast cancer effect of WYS may be associated with the regulation of cell cycle progression, mitochondrial apoptosis, and the MAPK signaling pathway. Subsequent in vitro functional assays validated that WYS inhibited the proliferation of MCF-7 cells in both dose- and time-dependent fashions, triggered G2/M phase arrest and intrinsic mitochondrial apoptosis, and inhibited the EGFR/MEK/ERK signaling axis, exhibiting limited cytotoxicity toward normal HUVEC cells. In vivo, WYS dose-dependently attenuated xenograft tumor growth, and its modulatory effects on cell cycle, apoptosis, and related signaling pathways were consistent with the in vitro observations. This study provides the first evidence that I. levis mycelial fraction WYS modulates EGFR/MEK/ERK-related signaling and induces G2/M cell cycle arrest, thereby exerting anti-proliferative and pro-apoptotic effects on MCF-7 breast cancer cells, providing a scientific basis for further investigation of I. levis as a functional food.