A UPLC-Q-TOF/MS-based plasma metabolomics approach reveals the mechanism of Compound Kushen Injection-based intervention against non-small cell lung cancer in Lewis tumor-bearing mice

Compound Kushen Injection (CKI), a well-known Chinese Medicine preparation, has been used to treat non-small cell lung cancer (NSCLC) for more than 15 years, and its clinical curative effect is considered to be beneficial. This study was designed to evaluate the effects and underlying mechanisms of CKI against NSCLC using an ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS)-based plasma metabolomics approach. 4′,6-diamidino-2-phenylindole (DAPI) staining and 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) dye reduction assay were employed to assess apoptosis and the viability of A549 cells with and without CKI treatment. The weight/volume of Lewis lung carcinoma (LLC) sarcomas and histopathological examinations were used to evaluate the anti-tumor effects of CKI against NSCLC. A UPLC-Q-TOF/MS method combined with multivariate data analysis was developed to characterize metabolomic fingerprinting and to screen functional biomarkers that are linked to the CKI treatment of LLC mice, and then metabolic pathway analysis was used to investigate the therapeutic mechanism of CKI. DAPI staining and MTT dye reduction assays indicated that CKI-induced apoptosis and inhibited the proliferation of A549 cells, respectively, in a concentration-dependent manner. The sarcoma volumes and weights in LLC tumor-bearing mice in CKI-dosed groups were significantly lower than those in a model group, which was treated with physiological saline. Histopathological analysis of sections of sarcomas and left pulmonary lobes indicated that CKI exerts an ameliorative effect against LLC. Fourteen functional biomarkers that are related to the therapeutic effects of CKI on LLC were screened and identified using a metabolomics study. Analysis of metabolic pathways revealed that the therapeutic effects of CKI on LLC mainly involved glycerophospholipid metabolism, amino acid metabolism and sphingolipid metabolism. As glycerophospholipid metabolism is a crucial feature of cancer-specific metabolism, the enzymes that are involved in 1-acyl-sn-glycero-3-phosphoinositol biosynthesis were further evaluated. Western blotting results indicated that CKI modulated the abnormal biosynthesis pathway of 1-acyl-sn-glycero-3-phosphoinositol by activation of cytidine diphosphate-diacylglycerol-inositol 3-phosphatidyltransferase (CDIPT) and cytosolic phospholipase A2 (cPLA2), and by inhibition of lysophosphatidic acid acyltransferase gamma (AGPAT3). This study demonstrated that CKI has a favorable anti-tumor effect and that a UPLC-Q-TOF/MS-based metabolomics method in conjunction with further verifications at the biochemical level is a promising approach for investigating its underlying mechanisms.