Tissue imaging and serum lipidomic profiling for screening potential biomarkers of thyroid tumors by matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry.

Changes in serum lipidome and in tissue lipidome are associated with cancer. In this study, tissue mass spectrometry imaging (MSI) and serum lipid profiling by matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) were performed to investigate significantly changed lipids in both tumor (malignant thyroid cancer (MTC) and benign thyroid tumor (BTT)) tissues and sera. Y-scatterplots of variable importance in the projection (VIP) values vs. fold change values indicate that change trends in the levels of ten lipids (i.e., phosphatidylcholine (PC)(34:1), PC(36:1), PC(38:6), phosphatidic acid (PA) (36:2), PA(36:3), PA(38:3), PA(38:4), PA(38:5), PA(40:5), and sphingomyelin (SM)(34:1)) in both tissues and sera from MTC patients, BTT patients, and normal individuals are significantly associated with these three types of pathophysiological status. In order to examine their diagnostic ability, 289 serum samples from 124 MTC patients, 43 BTT patients, and 122 normal controls were randomly divided into the training set and validation set. A biomarker of PC(34:1) exhibited excellent diagnostic ability to differentiate both MTC and BTT patients from normal individuals, with an area under the receiver operating characteristic (ROC) curve value of 0.984, a sensitivity of 96.4 %, and a specificity of 92.7 %. A panel which included PA(36:3) and SM(34:1) could distinguish between MTC and BTT, with an area under receiver operating characteristic curve (AUC) of 0.961, a sensitivity of 87.8 %, and a specificity of 92.9 %. It is worth noting that a panel consisting of PC(34:1), PA(36:3), and SM(34:1) could differentiate MTC patients from both BTT patients and normal individuals, with an AUC of 0.841, a sensitivity of 86.6 %, and a specificity of 75.5 %.

In Situ Characterizing Membrane Lipid Phenotype of Human Lung Cancer Cell Lines Using Mass Spectrometry Profiling.

Abnormal lipid metabolisms are closely associated with cancers. In this study, mass spectrometry was employed to in situ investigate the associations of membrane lipid phenotypes of six human lung cancer cell lines (i.e., A549, H1650, H1975 from adenocarcinoma, H157 and H1703 from squamous cell carcinomas, and H460 from a large cell carcinoma) with cancer cell types and finally total 230 lipids were detected. Based these 230 lipids, partial least-square discriminant analysis indicated that fifteen lipids (i.e., PE 18:0_18:1, PI 18:0_20:4, SM 42:2, PE 16:0_20:4, PE 36:2, PC 36:2, SM 34:1, PA 38:3,C18:0, C22:4, PA 34:2, C20:5, C20:2, C18:2, and CerP 36:2) with variable importance in the projection (VIP) value of > 1.0 could be used to differentiate six cancer cell lines with the Predicted Residual Sum of Square (PRESS) score of 0.1974. Positive correlation between polyunsaturated fatty acids (i.e., C20:4, C22:4, C22:5, and C22:6) and polyunsaturated phospholipids (PE 16:0_20:4, PE 38:4, and PI 18:0_20:4) was observed in lung adenocarcinoma cells, especially for H1975 cells. Three adenocarcinoma cell lines (i.e., A549, H1650, and H1975) could be differentiated from other lung cancer cell lines based on the expression of C18:1, C20:1, C20:2, C20:5, and C22:6.

In situ characterizing membrane lipid phenotype of breast cancer cells using mass spectrometry profiling.

Lipid composition in cell membrane is closely associated with cell characteristics. Here, matrix-assisted laser desorption/ionization- Fourier transform ion cyclotron resonance mass spectrometry was employed to in situ determine membrane components of human mammary epithelial cells (MCF-10 A) and six different breast cancer cell lines (i.e., BT-20, MCF-7, SK-BR-3, MDA-MB-231, MDA-MB-157, and MDA-MB-361) without any lipid extraction and separation. Partial least-square discriminant analysis indicated that changes in the levels of these membrane lipids were closely correlated with the types of breast cell lines. Elevated levels of polyunsaturated lipids in MCF-10 A cells relative to six breast cancer cells and in BT-20 cells relative to other breast cancer cell lines were detected. The Western blotting assays indicated that the expression of five lipogenesis-related enzymes (i.e., fatty acid synthase 1(FASN1), stearoyl-CoA desaturase 1 (SCD1), stearoyl-CoA desaturase 5 (SCD5), choline kinase α (CKα), and sphingomyelin synthase 1) was associated with the types of the breast cells, and that the SCD1 level in MCF-7 cells was significantly increased relative to other breast cell lines. Our findings suggest that elevated expression levels of FASN1, SCD1, SCD5, and CKα may closely correlated with enhanced levels of saturated and monounsaturated lipids in breast cancer cell lines.