OBJECTIVE To screen the active fraction of Cordyceps militaris (CM) exerting anti-lung cancer effects, investigate its effects on endogenous metabolites in lung cancer-bearing nude mice and explore the potential mechanism of action by non-targeted metabolomics.

METHODS The nucleosides (CMN) and polysaccharides (CMP) of CM were extracted and purified. The components in CMN were identified by UPLC-LTQ-Orbitrap X instrument. The model of human lung cancer xenograft in nude mice was established, and treated with CM and its different fraction extracts for two weeks. The active fraction of CM with anti-lung cancer effect was screened by monitoring tumor volume, tumor weight and histopathological alterations. Serum and tumor tissue samples were collected, and GC-MS technology was used for metabolomics analysis. The effects of CMN on lung cancer cells were evaluated by CCK-8, colony formation, wound healing assays and cell cycle analysis. The metabolic pathways involved in the anti-lung cancer effect of CMN were further verified by cellular metabolomics.

RESULTS A total of 13 components including cordycepin, inosine and adenine were identified from CMN. CMN significantly inhibited tumor growth with low toxicity. At the cellular level, CMN inhibited the proliferation, migration and cell cycle progression of lung cancer cells. A total of 38 differential metabolites were identified by serum metabolomics analyses, and 44 by tumor tissue metabolomics analyses, which were mainly involved in the citrate cycle (TCA cycle). This conclusion was further confirmed by differential metabolites identified through tumor cell metabolomics analyses.

CONCLUSION CMN is the active fraction of CM exerting anti-lung cancer effects, which might exert anti-lung cancer effects by regulating the TCA cycle pathway.