Breast cancer is the leading cause of cancer and mortality in women worldwide. Recent studies have argued that there is a close relationship between lipid synthesis and cancer progression because some enzymes related to lipid synthesis are overexpressed in breast cancer tissues. However, lipid distribution in breast cancer tissues has not been investigated. We aimed to visualize phosphatidylcholines (PCs) and lysoPCs (LPCs) in human breast cancer tissues by performing matrix assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS), which is a novel technique that enables the visualization of molecules comprehensively. Twenty-nine breast tissue samples were obtained during surgery and subjected to MALDI-IMS analysis. We evaluated the heterogeneity of the distribution of PCs and LPCs on the tissues. Three species [PC(32∶1), PC(34∶1), and PC(36∶1)] of PCs with 1 mono-unsaturated fatty acid chain and 1 saturated fatty acid chain (MUFA-PCs) and one [PC(34∶0)] of PCs with 2 saturated fatty acid chains (SFA-PC) were relatively localized in cancerous areas rather than the rest of the sections (named reference area). In addition, the LPCs did not show any biased distribution. The relative amounts of PC(36∶1) compared to PC(36∶0) and that of PC(36∶1) to LPC(18∶0) were significantly higher in the cancerous areas. The protein expression of stearoyl-CoA desaturase-1 (SCD1), which is a synthetic enzyme of MUFA, showed accumulation in the cancerous areas as observed by the results of immunohistochemical staining. The ratios were further analyzed considering the differences in expressions of the estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2), and Ki67. The ratios of the signal intensity of PC(36∶1) to that of PC(36∶0) was higher in the lesions with positive ER expression. The contribution of SCD1 and other enzymes to the formation of the observed phospholipid composition is discussed.

The identification of cancer biomarkers is critical for target-linked cancer therapy. The overall level of phosphatidylcholine (PC) is elevated in colorectal cancer (CRC). To investigate which species of PC is overexpressed in colorectal cancer, an imaging mass spectrometry was performed using a panel of non-neoplastic mucosal and CRC tissues. In the present study, we identified a novel biomarker, PC(16:0 ⁄ 16:1), in CRC using imaging mass spectrometry. Specifically, elevated levels of PC(16:0 ⁄ 16:1) expression were observed in the more advanced stage of CRC. Our data further showed that PC(16:0 ⁄ 16:1) was specifically localized in the cancer region when examined using imaging mass spectrometry. Notably, because the ratio of PC(16:0 ⁄ 16:1) to lyso-PC(16:0) was higher in CRC, we postulated that lyso-PC acyltransferase (LPCAT) activity is elevated in CRC. In an in vitro analysis, we showed that LPCAT4 is involved in the deregulation of PC (16: (1) Previous studies have reported that CRC contains increased amounts of phospholipids as well as an altered phospholipid composition of the CRC cell membrane.(2,3) These changes in membrane phospholipid levels can affect cell proliferation, viability and tumor development.(2,4) Moreover, although phosphatidylcholine (PC) is the most dominant phospholipid in both non-neoplastic and cancer tissues,the amount of PC is highly increased in CRC cells.(2) In addition, the changes in membrane potential and the increased PC ⁄ phosphatidylethanolamine (PE) composition rate are related to the grade of CRC malignancy.(3) In higher eukaryotes, PC is synthesized via two pathways: (i) the triple methylation of PE; and (ii) the cytidine diphosphate (CDP)-choline pathway. (6) However, the steady-state composition of PC species is maintained by the remodeling cycle (Lands' cycle).(7) The precise and concerted deacylation by phospholipase A 2 (PLA 2 ) and reacylation by lyso-PC acyltransferase (LPCAT) are required for normal cell functioning. Notably, the elevated expression of LPCAT1 was associated with colon cancer growth. (8) LPCAT1 is a member of the LPCAT family (LPCAT1-4) and shows LPCAT activity, preferentially incorporating palmitate into PC.(8) However, the relationship between PC remodeling and the progression of cancer, as well as the class of LPCAT involved in this process, remains unclear.Direct mass spectrometry (MS) of biological tissue sections using matrix-assisted laser desorption ⁄ ionization (MALDI) can profile many molecules including phospholipid subtypes. (9) Furthermore, this approach can be extended to imaging MS, which can visualize the distribution of biomolecules in the tissue section.(10-13) Because specific antibodies against lipids and macromolecules are often difficult to obtain, MALDI imaging is a suitable option for detecting distinct species of these molecules directly in a tissue section. This technique has already been applied to various human cancers including prostate and gastric cancer. (14,15) Although this emerging analytical technique was initial...

Thymic stromal lymphopoietin (TSLP) is overtly expressed on skin lesions of atopic dermatitis (AD), and the initiative role of TSLP-activated DCs in AD has gained much attention in the past few years, while its actions on other immune cells such as T cells have been given less notice. We aimed to clarify whether TSLP receptor (TSLPR) is expressed on certain populations of T cells and whether TSLP possesses the capability to directly interact with T cells from AD patients. Peripheral lymphocytes from 51 AD patients are analyzed by flow cytometry, and ex vivo experiments using peripheral blood and lesional skin-derived T cells were conducted. TSLPR expression was defined to CD4+ T cells, and CD4+CCR4+CXCR3-CCR7-CCR10+CLA+ T cells in AD patients exhibited enhanced TSLPR expression. The frequency of TSLPR+CD4+ T cells correlated with disease activity. CD4+ T cells from AD patients directly interacted with TSLP to produce a higher amount of IL-4 than those from normal subjects, and this action was attenuated with anti-TSLPR antibody. The importance of IL-4 in the induction of TSLPR expression was found in AD T cells. Our findings indicate that T cells from AD patients possess strong potential to directly interact with TSLP to promote Th2 response.

The etiology of schizophrenia includes phospholipid abnormalities. Phospholipids are bioactive substances essential for brain function. To analyze differences in the quantity and types of phospholipids present in the brain tissue of patients with schizophrenia, we performed a global analysis of phospholipids in multiple brain samples using liquid chromatography electrospray ionization mass/mass spectrometry (LC-ESI/MS/MS) and imaging mass spectrometry (IMS). We found significantly decreased 16:0/20:4-phosphatidylinositol (PI) levels in the prefrontal cortex (PFC) in the brains from patients with schizophrenia in the LC-ESI/MS/MS, and that the 16:0/20:4-PI in grey matter was most prominently diminished according to the IMS experiments. Previous reports investigating PI pathology of schizophrenia did not identify differences in the sn-1 and sn-2 fatty acyl chains. This study is the first to clear the fatty acid composition of PI in brains from patients with schizophrenia. Alteration in the characteristic fatty acid composition of PI may also affect neuronal function, and could play a role in the etiology of schizophrenia. Although further studies are necessary to understand the role of reduced 16:0/20:4-PI levels within the prefrontal cortex in the etiology of schizophrenia, our results provide insight into the development of a novel therapy for the clinical treatment of schizophrenia.

Accumulating evidence indicates that cancer cells show specific alterations in phospholipid metabolism that contribute to tumour progression in several types of cancer, including colorectal cancer. Questions still remain as to what lipids characterize the outer edge of cancer tissues and whether those cancer outer edge-specific lipid compositions emerge autonomously in cancer cells. Cancer tissue-originated spheroids (CTOSs) that are composed of pure primary cancer cells have been developed. In this study, we aimed to seek out the cancer cell-autonomous acquisition of cancer outer edge-characterizing lipids in colorectal cancer by analysing phospholipids in CTOSs derived from colorectal cancer patients with matrix-assisted laser desorption/ionization (MALDI)-imaging mass spectrometry (IMS). A signal at m/z 885.5 in negative ion mode was detected specifically at the surface regions. The signal was identified as an arachidonic acid (AA)-containing phosphatidylinositol (PI), PI(18:0/20:4), by tandem mass spectrometry analysis. Quantitative analysis revealed that the amount of PI(18:0/20:4) in the surface region of CTOSs was two-fold higher than that in the medial region. Finally, PI(18:0/20:4) was enriched at the cancer cells/stromal interface in colorectal cancer patients. These data imply a possible importance of AA-containing PI for colorectal cancer progression, and suggest cells expressing AA-containing PI as potential targets for anti-cancer therapy.