Jeong Hwa Lee

Identification and characterization of proteins isolated from microvesicles derived from human lung cancer pleural effusions

Microvesicles (MVs, also known as exosomes, ectosomes, microparticles) are released by various cancer cells, including lung, colorectal, and prostate carcinoma cells. MVs released from tumor cells and other sources accumulate in the circulation and in pleural effusion. Although recent studies have shown that MVs play multiple roles in tumor progression, the potential pathological roles of MV in pleural effusion, and their protein composition, are still unknown. In this study, we report the first global proteomic analysis of highly purified MVs derived from human nonsmall cell lung cancer (NSCLC) pleural effusion. Using nano‐LC–MS/MS following 1D SDS‐PAGE separation, we identified a total of 912 MV proteins with high confidence. Three independent experiments on three patients showed that MV proteins from PE were distinct from MV obtained from other malignancies. Bioinformatics analyses of the MS data identified pathologically relevant proteins and potential diagnostic makers for NSCLC, including lung‐enriched surface antigens and proteins related to epidermal growth factor receptor signaling. These findings provide new insight into the diverse functions of MVs in cancer progression and will aid in the development of novel diagnostic tools for NSCLC.

A new combination MALDI matrix for small molecule analysis: application to imaging mass spectrometry for drugs and metabolites

Since the development of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, this procedure has been specifically used for analyzing proteins or high molecular weight compounds because of the interference of matrix signals in the regions of the low mass range. Recently, scientists have been using a wide range of chemical compounds as matrices that ionize small molecules in a mass spectrometer and overcome the limitations of MALDI mass spectrometry. In this study, we developed a new combination matrix of 3-hydroxycoumarin (3-HC) and 6-aza-2-thiothymine (ATT), which is capable of ionizing small molecules, including drugs and single amino acids. In addition to ionization of small molecules, the combination matrix by itself gives less signals in the low mass region and can be used for performing imaging mass spectrometry (IMS) experiments on tissues, which confirms the vacuum stability of the matrix inside a MALDI chamber. The drug donepezil was mapped in the intact tissue slices of mice simultaneously with a spatial resolution of 150 μm during IMS. IMS analysis clearly showed that intact donepezil was concentrated in the cortical region of the brain at 60 min after oral administration. Our observations and results indicate that the new combination matrix can be used for analyzing small molecules in complex samples using MALDI mass spectrometry.

Lipid MALDI profile classifies non-small cell lung cancers according to the histologic type

We investigated whether direct tissue matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) analysis on lipid may assist with the histopathologic diagnosis of non-small cell lung cancers (NSCLCs). Twenty-one pairs of frozen, resected NSCLCs and adjacent normal tissue samples were initially analyzed using histology-directed, MALDI MS. 2,5-dihydroxybenzoic acid/α-cyano-4-hydroxycinnamic acid were manually deposited on areas of each tissue section enriched in epithelial cells to identify lipid profiles, and mass spectra were acquired using a MALDI-time of flight instrument. A lipid profile that could differentiate cancer and adjacent normal samples with a median accuracy of 92.9% was discovered. Several phospholipids including phosphatidylcholines (PC) {34:1} were overexpressed in lung cancer. Squamous cell carcinomas and adenocarcinomas were found to have different lipid profiles. Discriminatory lipids correctly classified the histology of 80.4% of independent NSCLC surgical tissue samples (41 out of 51) in validation set. MALDI MS image of 11 discriminatory lipids validated their differential expression according to the histologic type in cancer cells of bronchoscopic biopsy samples. PC {32:0} [M+Na](+) (m/z 756.68) and ST-OH {42:1} [M-H](-) (m/z 906.89) were overexpressed in adenocarcinomas. Thus, lipid profiles accurately distinguish tumor from adjacent normal tissue and classify non-small cell lung cancers according to the histologic type.

Protein and lipid MALDI profiles classify breast cancers according to the intrinsic subtype

BackgroundMatrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) has been demonstrated to be useful for molecular profiling of common solid tumors. Using recently developed MALDI matrices for lipid profiling, we evaluated whether direct tissue MALDI MS analysis on proteins and lipids may classify human breast cancer samples according to the intrinsic subtype.MethodsThirty-four pairs of frozen, resected breast cancer and adjacent normal tissue samples were analyzed using histology-directed, MALDI MS analysis. Sinapinic acid and 2,5-dihydroxybenzoic acid/α-cyano-4-hydroxycinnamic acid were manually deposited on areas of each tissue section enriched in epithelial cells to identify lipid profiles, and mass spectra were acquired using a MALDI-time of flight instrument.ResultsProtein and lipid profiles distinguish cancer from adjacent normal tissue samples with the median prediction accuracy of 94.1%. Luminal, HER2+, and triple-negative tumors demonstrated different protein and lipid profiles, as evidenced by permutation P values less than 0.01 for 0.632+ bootstrap cross-validated misclassification rates with all classifiers tested. Discriminatory proteins and lipids were useful for classifying tumors according to the intrinsic subtype with median prediction accuracies of 80.0-81.3% in random test sets.ConclusionsProtein and lipid profiles accurately distinguish tumor from adjacent normal tissue and classify breast cancers according to the intrinsic subtype.

Global changes in phospholipids identified by MALDI MS in rats with focal cerebral ischemia

Neuronal membrane phospholipids are highly affected by oxidative stress caused by ischemic injury. Thus, it is necessary to identify key lipid components that show changes during ischemia to develop an effective approach to prevent brain damage from ischemic injury. The recent development of MALDI imaging MS (MALDI IMS) makes it possible to identify phospholipids that change between damaged and normal regions directly from tissues. In this study, we conducted IMS on rat brains damaged by ischemic injury and detected various phospholipids that showed unique distributions between normal and damaged areas of the brain. Among them, we confirmed changes in phospholipids such as lysophosphatidylcholine, phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin by MALDI IMS followed by MS/MS analysis. These lipids were present in high concentrations in the brain and are important for maintenance of cellular structure as well as production of second messengers for cellular signal transduction. Our results emphasize the identification of phospholipid markers for ischemic injury and successfully identified several distinctly located phospholipids in ischemic brain tissue.

Phosphatidylcholine alteration identified using MALDI imaging MS in HBV-infected mouse livers and virus-mediated regeneration defects.

In this study, we investigated whether hepatitis B virus (HBV) causes the alteration of lipid metabolism and composition during acute infection and liver regeneration in a mouse model. The liver controls lipid biogenesis and bile acid homeostasis. Infection of HBV causes various liver diseases and impairs liver regeneration. As there are very few reports available in the literature on lipid alterations by HBV infection or HBV-mediated liver injury, we have analyzed phospholipids that have important roles in liver regeneration by using matrix-assisted laser desorption/ionization (MALDI)-imaging mass spectrometry (IMS) in the livers of HBV model mice. As a result, we identified different phosphatidylcholines (PCs) showing significant changes in their composition as well as cationized ion adduct formation in HBV-infected mouse livers which are associated with virus-mediated regeneration defects. To find the factor of altered PCs, the expression kinetics of enzymes was also examined that regulate PC biosynthesis during liver regeneration. It is noteworthy that the expression of choline-phosphate cytidylyltransferase A (PCYT1A) was significantly delayed in wild type HBV-expressing livers. Moreover, the amount of hepatic total PC was also significantly decreased in wt HBV-expressing mice. These results suggest that infection of HBV alters the composition of PCs which may involve in HBV-mediated regeneration defects and liver disease.

Imaging mass spectrometry in papillary thyroid carcinoma for the identification and validation of biomarker proteins.

Direct tissue imaging mass spectrometry (IMS) by matrix-assisted laser desorption ionization and time-of-flight (MALDI-TOF) mass spectrometry has become increasingly important in biology and medicine, because this technology can detect the relative abundance and spatial distribution of interesting proteins in tissues. Five thyroid cancer samples, along with normal tissue, were sliced and transferred onto conductive glass slides. After laser scanning by MALDI-TOF equipped with a smart beam laser, images were created for individual masses and proteins were classified at 200-µm spatial resolution. Based on the spatial distribution, region-specific proteins on a tumor lesion could be identified by protein extraction from tumor tissue and analysis using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Using all the spectral data at each spot, various intensities of a specific peak were detected in the tumor and normal regions of the thyroid. Differences in the molecular weights of expressed proteins between tumor and normal regions were analyzed using unsupervised and supervised clustering. To verify the presence of discovered proteins through IMS, we identified ribosomal protein P2, which is specific for cancer. We have demonstrated the feasibility of IMS as a useful tool for the analysis of tissue sections, and identified the tumor-specific protein ribosomal protein P2. Graphical Abstract

Low C24-OH and C22-OH sulfatides in human renal cell carcinoma.

Histopathologic diagnosis of renal cell carcinoma (RCC) may sometimes be difficult with small biopsy samples. We applied histology-directed matrix-assisted laser desorption/ionization mass spectrometry to RCC samples to evaluate whether and how lipid profiles are different between RCC and normal tissue. We evaluated 59 RCC samples and 24 adjacent normal tissue samples collected from patients who underwent surgery. Five peaks were significantly differently expressed (p < 10(-7)) between RCCs and adjacent normal tissue samples. C24-OH sulfatide (ST-OH {18:1/24:0}[M-H](-); m/z 906.7 in the negative ion mode) and C22-OH sulfatide (ST-OH {18:1/22:0}[M-H](-); m/z 878.6 in the negative ion mode) were most significantly underexpressed in RCC samples, compared with adjacent normal tissue samples. With 100 random training-to-test partitions within these samples, the median prediction accuracy (RCC vs. normal) ranged from 96.3% to 100% at p cutoff values for feature selection ranging from 0.001 to 10(-7). Two oncocytoma samples were predicted as normal tissue by five lipids that were differentially expressed between RCC and normal tissue at p < 10(-7). Clear-cell, papillary, and chromophobe RCCs were different in lipid profiles. Permutation p- values for 0.632+ bootstrap cross-validated misclassification rates were less than 0.05 for all the classifiers. Thus, lipid profiles differentiate RCC from normal tissue and may possibly classify the histology of RCC.

Immune-enhancing activity of phosvitin by stimulating the production of pro-inflammatory mediator

ABSTRACT Egg yolk phosvitin is one of the most phosphorylated proteins in nature, and the extraordinarily high concentration of phosphate groups in its structure provides a strong metal‐binding ability. Phosvitin is known to possess various functional activities, including metal‐chelating, antioxidant, emulsifying, antimicrobial, and cytotoxic activities. However, little is known about the immune‐enhancing activity of phosvitin. The objective of this study was to evaluate the immune‐enhancing activity of phosvitin in murine RAW 264.7 macrophages. Griess reagents and quantitative real‐time PCR were used to determine the effect of phosvitin (at 12.5, 25, 50, and 100 &mgr;g/mL) on the levels of pro‐inflammatory mediators NO and inducible nitric oxide synthase (iNOS), cytokines TNF‐&agr; and IL‐1&bgr; in RAW 264.7 macrophages. The effect of phosvitin on the phagocytic activity of RAW 264.7 macrophages was also measured using the Neutral‐Red Uptake method. Lipopolysaccharides was used as a positive control. Phosvitin significantly (P < 0.05) increased the production of NO in RAW 264.7 macrophages in a dose‐dependent manner, but did not show any cytotoxicity. The amounts of NO produced were 3.47, 7.12, 10.23, and 14.57 &mgr;M in 12.5 to 100 &mgr;g/mL range of phosvitin (control: 0.46 &mgr;M). Compared with the untreated group, phosvitin treatment at a 100 &mgr;g/mL level increased the production of NO by 31.67 times. Phosvitin also significantly increased the mRNA expression of the RAW 264.7 macrophages: 100 &mgr;g/mL of phosvitin treatment increased the expression of mRNA for iNOS, TNF‐&agr;, and IL‐1&bgr; by 46.25, 9.09, and 85.18 times of the control, respectively. The phagocytic activity of RAW 264.7 macrophages was also increased significantly by phosvitin treatment. These results demonstrated that phosvitin dramatically improved the immune functions RAW 264.7 macrophages by enhancing the production of immune mediators and increasing phagocytic activity. Therefore, phosvitin has a potential to be used as an immune‐enhancing agent by food or nutraceutical industries.

Lipid MALDI MS Profiles of Gastric Cancer

Tissue matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS)may identify lipids differentially expressed between cancer and adjacent normal tissue. To identify lipidomic profiles for gastric cancer, 24 gastric cancerswere profiled for lipid by the histology-directed, tissue MALDI MS technology. Lipid profiles differed between gastric cancer and adjacent normal tissue samples. At P<0.05, median class prediction accuracy in 100 random training-to-test partitions was 83.3% (5/6) for all classifiers tested. A peak at m/z 741.6 (sphingomyelin 34:1 K) was overexpressed, and a peak at m/z 782.6 (phosphatidylcholine 34:1 Na) was underexpressed in gastric cancers compared with normal tissue. Thus, lipid MALDI MS analysis may capture a global alteration in lipid profile of gastric cancer tissue, distinguishing cancerous epithelium from normal epithelium.