Discovery of potential biomarkers in human melanoma cells with different metastatic potential by metabolic and lipidomic profiling

Abstract

Malignant melanoma, characterized by its ability to metastasize to other organs, is responsible for 90% of skin cancer mortality. To investigate alterations in the cellular metabolome and lipidome related to melanoma metastasis, gas chromatography-mass spectrometry (GC-MS) and direct infusion-mass spectrometry (DI-MS)-based metabolic and lipidomic profiling were performed on extracts of normal human melanocyte (HEMn-LP), low metastatic melanoma (A375, G361), and highly metastatic melanoma (A2058, SK-MEL-28) cell lines. In this study, metabolomic analysis identified aminomalonic acid as a novel potential biomarker to discriminate between different stages of melanoma metastasis. Uptake and release of major metabolites as hallmarks of cancer were also measured between high and low metastatic melanoma cells. Lipid analysis showed a progressive increase in phosphatidylinositol (PI) species with saturated and monounsaturated fatty acyl chains, including 16:0/18:0, 16:0/18:1, 18:0/18:0, and 18:0/18:1, with increasing metastatic potential of melanoma cells, defining these lipids as possible biomarkers. In addition, a partial-least-squares projection to latent structure regression (PLSR) model for the prediction of metastatic properties of melanoma was established, and central metabolic and lipidomic pathways involved in the increased motility and metastatic potential of melanoma cells were identified as therapeutic targets. These results could be used to diagnose and control of melanoma metastasis.

Human Melanoma-Cell Metabolic Profiling: Identification of Novel Biomarkers Indicating Metastasis

“…Beyond this metabolic reprogramming, and since glucose is converted almost quantitatively to lactic acid, the TCA (tricarboxylic acid) cycle functions, regardless of oxygen presence, in the reverse direction, using glutamine as an alternative carbon source [10]. Elevated glycolysis and glutaminolysis could explain the absence of both glucose and glutamine metabolites from the two cell lines, WM115 and WM2664, but most importantly the significant increase in lactic acid (FC NMR = 3.27) and glutamic acid (FC NMR = 4.84; FC MS = 5.81), as well as in the TCA cycle intermediates fumaric acid (FC NMR = 2.01) and succinic acid (FC NMR = 4.82; FC MS = 4.04) [11], in the metastatic melanoma cell line WM2664. A rise in the (metabolite-linker) alanine content [10] from implementation of these two processes is expected, since alanine aminotransferase catalyzes the transfer of an amino group from glutamic to pyruvic acid, with alanine and oxoglutaric acid being the reaction products.…”

“…The metabolite that demonstrated the most striking difference between the two cell lines, WM115 and WM2664, was hypoxanthine, whose concentration was measured at least 14-fold (x) higher in WM2664 (FC NMR = 14.05; FC MS = 94.26), as compared to WM115 (reference) cells. Metabolic studies for gastric cancer and melanoma have described higher plasma and tissue levels, due to higher tumor-cell proliferation rates, conditions under which hypoxanthine acts as a substrate and source of nitrogen [11,47]. Hypoxanthine is formed via the Purine Biosynthesis Pathway (PBP) [48] that is characterized by the conversion of ribose 5-phosphate to inosine monophosphate (FC NMR = 1.45), which is, then, dephosphorylated to inosine, the major hypoxanthine precursor molecule.…”

“…Branched-chain amino acids (BCAAs) are essential components of proteins, mainly due to their hydrophobicity, and, therefore, in oncogenic conditions of increased protein synthesis and energy requirement, their consumption and oxidation are often intensified [52]. Although results from other metabolic cancer studies converge to the experimental reduction of BCAAs [11,49], differentiation of their levels has not proved consistent [50].…”

“…Specifically, cell metabolomics, despite the demanding sample processing, offer a direct insight in metabolic reprogramming, while it is cost-effective, ethically acceptable and of minimum biological variability [8,9].Recent metabolomics studies on melanoma have employed either NMR-or MS-based analytical techniques. Melanocytes and various melanoma cell lines of dissimilar metastatic potentials and incomparable mutational signatures were explored, using GC-MS and Direct Infusion MS (DI-MS), confirming glucose and glutamine switched metabolisms, and revealing considerably perturbed alanine and aspartic acid pathways [10,11]. Melanoma cells have also been examined by employing NMR analysis, which underlined the enhanced glutaminolysis and oxidative phosphorylation, as well as the deregulated choline and lipid metabolism [12,13].…”

Phospholipid profiling enables to discriminate tumor- and non-tumor-derived human colon epithelial cells: Phospholipidome similarities and differences in colon cancer cell lines and in patient-derived cell samples

“…In contrast, we observed that both SW480 and SW620 cells were rather similar in terms of their PL profiles, as suggested by PCA. However, specific PL profiles, as well as accumulation of some PL species (in particular PS, PI and PE) have been proposed to be linked with metastatic potential and aggressiveness of tumor cells in other cancer types, including breast cancer or melanomas, or to increase directly in metastatic cells [44,[48][49][50][51]. This would suggest that, in addition to general alterations of lipid metabolism, PL can be expected to increase also in colon cancer metastases.…”