Plasma metabolomics combined with mass spectrometry imaging reveals crosstalk between tumor and plasma in gastric cancer genesis and metastasis

Gastric Carcinoma (GC) is a highly fatal malignant tumor with a poor prognosis. Its elevated mortality rates are primarily due to its proclivity for late-stage metastasis. Exploring the metabolic interactions between tumor microenvironment and the systemic bloodstream could help to clearly understand the mechanisms and identify precise biomarkers of tumor growth, proliferation, and metastasis. In this study, an integrative approach that combines plasma metabolomics with mass spectrometry imaging of tumor tissue was developed to investigate the global metabolic landscape of GC tumorigenesis and metastasis. The results showed that the oxidized glutathione to glutathione ratio (GSSH/GSH) became increased in non-distal metastatic GC (M0), which means an accumulation of oxidative stress in tumor tissues. Furthermore, it was found that the peroxidation of polyunsaturated fatty acids, such as 9,10-EpOMe, 9-HOTrE, etc., were accelerated in both plasma and tumor tissues of distal metastatic GC (M1). These changes were further confirmed the potential effect of CYP2E1 and GGT1 in metastatic potential of GC by mass spectrometry imaging (MSI) and immunohistochemistry (IHC). Collectively, our findings reveal the integrated multidimensional metabolomics approach is a clinical useful method to unravel the blood-tumor metabolic crosstalk, illuminate reprogrammed metabolic networks, and provide reliable circulating biomarkers.