Lipid Metabolite Profiles Research Articles

Abstract PR05: Unique lipid metabolite profiling in BRAFV600E inhibitor drug-resistant melanoma and their potential as drug target

Abstract Melanoma is the most life-threatening skin cancer in the world. Advanced melanoma is highly metastatic, commonly develops drug resistance, and causes low survival rate in patients. PLX4032 (vemurafenib), a BRAFV600E inhibitor, is used to treat patients with late-stage melanoma. It showed initial good clinical responses but relapsed due to acquired drug resistance in tumors. The mechanism of PLX4032-induced resistance in melanoma is not well characterized; in particular, whether PLX4032-induced drug resistance in BRAF mutant melanoma would alter lipid metabolism in cancer is not clear. Understanding the status and role of lipid mediators (oxylipins) in melanoma pathology may be crucial for developing effective approach to overcome drug resistance. Our laboratory has demonstrated that plant sesquiterpene lactone deoxyelephantopin (DET) and its novel derivative DETD-35 effectively suppressed human A375 BRAFV600E melanoma with acquired drug resistance to PLX4032 in vitro and in xenograft mice. In this study we aimed to identify potential biomarkers associated with the resistant melanoma cells (A375-R) in the context of bioactive lipid mediators and to investigate whether DETD-35/DET effects against drug-resistant melanoma are through regulating their dynamics and contents. MS-based metabolomics was used to comprehensively analyze the oxylipin profiles in A375 and A375-R cells, mouse A375/A375-R tumor tissues, and respective sera with vehicle, drug, or compound treatment. We observed that PLX4032-resistant A375R melanoma cells or tumors produce significant and higher amounts of CYP450 enzyme-derived oxylipins than the parental A375, which were decreased after DETD-35 or DET treatment. This study proposes a role of CYP450-derived oxylipins in PLX4032-resistant melanoma cells and its potential to be a drug target. This abstract is also being presented as Poster B03. Citation Format: Meng-Ting Chang, Jia-Hua Feng, Kyoko Nakagawa-Goto, Kuo-Hsiung Lee, Lie-Fen Shyur. Unique lipid metabolite profiling in BRAFV600E inhibitor drug-resistant melanoma and their potential as drug target [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr PR05.

Profile of serum lipid metabolites of one-week-old goat kids depending on the type of rearing

BackgroundWeaning of goat kids immediately after birth and feeding them on bovine or heat-treated caprine colostrum, referred to as snatching, is considered an effective control measure in some infectious diseases. The study was carried out in one-week-old goat kids to gain insight into the profile of lipid metabolites and to investigate the influence of snatching on kids’ metabolism. Fifty-two goat kids born to 23 female goats were included in the study – 22 kids were weaned immediately after birth and kept isolated from their mothers; 30 remaining kids were left with their mothers for next 3 weeks so that they could nurse on dams’ milk at will. Blood was collected at the age of 1 week and serum was obtained by centrifugation. The concentration of lipid metabolites was determined with mass spectrometry using a commercial MxP® Quant 500 kit (Biocrates Life Sciences AG, Innsbruck, Austria).ResultsConcentration of 240 lipid metabolites belonging to 10 lipid classes was above the limit of detection of the assay. These lipid metabolites were quantified and included in the analysis. Concentration of 2 lipid classes (acyl-alkyl-phosphatidylcholines and ceramides) and 31 lipid metabolites (14 triacylglycerols, 5 acyl-alkyl-phosphatidylcholines, 2 diacylphosphatidylcholines, 1 lyso-phosphatidylcholine, 5 ceramides, 2 sphingomyelins, and 2 cholesterol esters) differed significantly between the two groups of kids.ConclusionSnatching of kids results in reduction of serum concentration of lipid metabolites, however, the magnitude of this phenomenon does not seem to be sufficient to negatively affect kids’ health condition. This study is the first in which the broad set of lipid metabolites of young ruminants was quantified using the novel metabolomic assay MxP® Quant 500 kit.

Multimodal MALDI Imaging Mass Spectrometry Reveals Spatially Correlated Lipid and Protein Changes in Mouse Heart with Acute Myocardial Infarction.

Acute myocardial infarction (MI) is a cardiovascular disease that remains a major cause of morbidity and mortality worldwide despite advances in its prevention and treatment. During acute myocardial ischemia, the lack of oxygen switches the cell metabolism to anaerobic respiration, with lactate accumulation, ATP depletion, Na+ and Ca2+ overload, and inhibition of myocardial contractile function, which drastically modifies the lipid, protein, and small metabolite profile in the myocardium. Imaging mass spectrometry (IMS) is a powerful technique to comprehensively elucidate the spatial distribution patterns of lipids, peptides, and proteins in biological tissue sections. In this work, we demonstrate an application of multimodal chemical imaging using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), which provided comprehensive molecular information in situ within the same mouse heart tissue sections with myocardial infarction. MALDI-IMS (at 30 μm per pixel) revealed infarct-associated spatial alterations of several lipid species of sphingolipids, glycerophospholipids, lysophospholipids, and cardiolipins along with the acyl carnitines. Further, we performed multimodal MALDI-IMS (IMS3) where dual polarity lipid imaging was combined with subsequent protein MALDI-IMS analysis (at 30 μm per pixel) within the same tissue sections, which revealed accumulations of core histone proteins H4, H2A, and H2B along with post-translational modification products, acetylated H4 and H2A, on the borders of the infarcted region. This methodology allowed us to interpret the lipid and protein molecular pathology of the very same infarcted region in a mouse model of myocardial infarction. Therefore, the presented data highlight the potential of multimodal MALDI imaging mass spectrometry of the same tissue sections as a powerful approach for simultaneous investigation of spatial infarct-associated lipid and protein changes of myocardial infarction.

The profile of lipid metabolites in urine of marmoset wasting syndrome.

Marmoset wasting syndrome (MWS) is clinically characterized by progressive weight loss. Although morbidity and mortality of MWS are relatively high in captive marmosets, its causes remain unknown. Lipid mediators are bioactive metabolites which are produced from polyunsaturated fatty acids, such as arachidonic acid (AA) and eicosapentaenoic acid. These lipid metabolites regulate a wide range of inflammatory responses and they are excreted into the urine. As urinary lipid profiles reflect systemic inflammatory conditions, we comprehensively measured the levels of 141 types of lipid metabolites in the urines obtained from healthy common marmoset (Callithrix jacchus) (N = 7) or marmosets with MWS (N = 7). We found that 41 types of metabolites were detected in all urine samples of both groups. Among them, AA-derived metabolites accounted for 63% (26/41 types) of all detected metabolites. Notably, the levels of AA-derived prostaglandin (PG) E2, PGF2α, thromboxane (TX) B2 and F2-isoprostanes significantly increased in the urine samples of marmosets with MWS. In this study, we found some urinary lipid metabolites which may be involved in the development of MWS. Although the cause of MWS remains unclear, our findings may provide some insight into understanding the mechanisms of development of MWS.

Ionizing radiation induces cutaneous lipid remolding and skin adipocytes confer protection against radiation-induced skin injury

BackgroundRadiation-induced skin injury is a serious concern during radiotherapy and radiation accidents. Skin fat represents the dominant architectural component of the human skin. However, the interplay between skin fat and the progression of radiation-induced skin injury remains largely unexplored. ObjectiveThis study aims to elucidate the interplay between skin fat and the progression of radiation-induced skin injury. MethodsSD rats were irradiated with an electron beam. mRNA profiles were determined by RNA-Seq. The skin lipid mass was monitored by magnetic resonance imaging (MRI) and lipid profiles were measured by liquid chromatography-mass spectrometry (LC–MS). Human mature adipocytes isolated from dermal and subcutaneous white adipose tissues (WATs) were co-cultured with human keratinocytes (HaCaT) and skin fibroblasts (WS1) in the transwell culture system. Cell migration ability was measured by migration assay. ResultsRadiation modulated cutaneous lipid metabolism by downregulating multiple pathways. Moreover, radiation decreased skin fat mass with altered lipid metabolite profiles. The rats fed with a high-fat diet showed resistance to radiogenic skin injury compared with that with a control diet, indicating that skin lipid plays a radioprotective role. Mature adipocytes promoted the migration but not the proliferation of co-cultured skin keratinocytes and fibroblasts. Palmitic acid, the most abundant fatty acid in skin tissues, facilitated the migration of WS1 cells. Moreover, fatty acid-binding protein 4 (FABP4) could be incorporated into skin cells and promote DNA damage repair in irradiated skin fibroblasts. ConclusionRadiation induces cutaneous lipid remolding, and skin adipocytes confer a protective role against radiation-induced skin injury.

High-Performance Liquid Chromatography-Mass Spectrometry-Based Lipid Metabolite Profiling of Acromegaly

Metabolic disorders, especially dysregulated lipid metabolism, increase the risk of cardiovascular mortality in acromegaly. Previous studies measuring plasma macromolecular lipids have yielded conflicting results. To explore the plasma lipid metabolite profiles by metabolomics analysis and identify potential metabolites associated with cardiac function in acromegaly. Plasma was obtained from 80 newly diagnosed, untreated patients with acromegaly and 80 healthy controls. Echocardiography was performed. Based on the results of an oral glucose tolerance test (OGTT), patients were categorized into 2 groups: normal glucose tolerance (NGT, n = 28) and impaired glucose tolerance or diabetes mellitus (IGT/DM, n = 52). High-performance liquid chromatography-mass spectrometry (HPLC-MS)-based metabolomics analysis was conducted. Data were processed by principal components analysis (PCA), orthogonal partial least square-discriminant analysis (OPLS-DA), and MetaboAnalyst 4.0. Associations between metabolic substances and cardiovascular parameters were also explored. Metabolomics uncovered a distinct metabolic pattern between acromegaly and healthy controls, and perturbed pathways mainly include glycerophospholipid metabolism, sphingolipid metabolism, as well as linoleic acid metabolism. Collective analysis showed that phosphatidylethanolamine (PE) (22:6/16:0) was positively correlated with LV mass, while lysophosphatidylcholine (LysoPC) (16:0) was positively correlated with fractional shortening (FS) and left ventricle ejection fraction (LVEF). Patients with acromegaly have distinct lipid metabolite profiling, while PE (22:6/16:0) and LysoPC (16:0) are correlated with cardiac structure and function, which may contribute to the risk of cardiovascular complications.

The profile of urinary lipid metabolites in cats.

Polyunsaturated fatty acids including arachidonic acid (AA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are converted to lipid mediators by oxidation. Unlike other mammals, cats cannot synthesize AA. Since their lipid metabolic features remain unknown, we qualitatively analyzed 118 types of urinary lipid metabolites in healthy neutered cats. Using LC-MS, we found 26 lipid metabolites in urines of all individuals. In detail, 20 AA-, 5 EPA- and 1 DHA-derived lipid mediators were detected. Focusing on oxidative pathway, 17 cyclooxygenase-metabolites and 5 metabolites produced by non-enzymatic pathway were detected. Of interest, few lipoxygenase- or cytochrome P450-metabolites were excreted. Thus, AA-derived cyclooxygenase-metabolites mainly composed the urinary lipid metabolites in cats.

Corticosterone-mediated physiological stress modulates hepatic lipid metabolism, metabolite profiles, and systemic responses in chickens

The impact of physiological stress on lipid metabolism, the metabolome, and systemic responses was examined in chickens. To incite a stress response, birds were continuously administered corticosterone (CORT) in their drinking water at three doses (0 mg/L, 10 mg/L, and 30 mg/L), and they were sampled 1, 5, and 12 days after commencement of CORT administration. Corticosterone administration to birds differentially regulated lipogenesis genes (i.e. FAS, ACC, ME, and SREBF1), and histopathological examination indicated lipid deposition in hepatocytes. In addition, CORT affected water-soluble metabolite profiles in the liver, as well as in kidney tissue and breast muscle; thirteen unique metabolites were distinguished in CORT-treated birds and this was consistent with the dysregulation of lipid metabolism due to physiological stress. Acute phase responses (APRs) were also altered by CORT, and in particular, expression of SAA1 was decreased and expression of CP was increased. Furthermore, CORT administration caused lymphoid depletion in the bursa of Fabricius and elevated IL6 and TGFβ2 mRNA expression after 5 and 12 days of CORT administration. Collectively, incitement of physiological stress via administration of CORT in chickens modulated host metabolism and systemic responses, which indicated that energy potentials are diverted from muscle anabolism during periods of stress.

DHRS2 mediates cell growth inhibition induced by Trichothecin in nasopharyngeal carcinoma

BackgroundCancer is fundamentally a deregulation of cell growth and proliferation. Cancer cells often have perturbed metabolism that leads to the alteration of metabolic intermediates. Dehydrogenase/reductase member 2 (DHRS2) belongs to short-chain alcohol dehydrogenase/reductase (SDR) superfamily, which is functionally involved in a number of intermediary metabolic processes and in the metabolism of lipid signaling molecules. DHRS2 displays closely association with the inhibition of cell proliferation, migration and quiescence in cancers.Methods3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4- sulfophenyl)-2H-tetrazolium (MTS), 5-ethynyl-2′-deoxyuridine (EdU) and colony formation assays were applied to evaluate the proliferative ability of nasopharyngeal carcinoma (NPC) cells. We performed lipid metabolite profiling using gas chromatography coupled with mass spectrometry (GC/MS) to identify the proximal metabolite changes linked to DHRS2 overexpression. RNA sequencing technique combined with differentially expressed genes analysis was applied to identify the expression of genes responsible for the anti-tumor effect of trichothecin (TCN), a natural sesquiterpenoid compound isolated from an endophytic fungus.ResultsOur current findings reveal that DHRS2 affects lipid metabolite profiling to induce cell cycle arrest and growth inhibition in NPC cells. Furthermore, we demonstrate that TCN is able to induce growth inhibition of NPC in vitro and in vivo by up-regulating DHRS2.ConclusionsOur report suggests that activating DHRS2 to reprogram lipid homeostasis may be a target for the development of targeted therapies against NPC. Moreover, TCN could be exploited for therapeutic gain against NPC by targeting DHRS2 and it may also be developed as a tool to enhance understanding the biological function of DHRS2.

Maternal Restricted- and Over-Feeding During Gestation Result in Distinct Lipid and Amino Acid Metabolite Profiles in the Longissimus Muscle of the Offspring.

Maternal over- and restricted-feeding during gestation have similar negative consequences for the offspring, including decreased muscularity, increased adiposity, and altered metabolism. Our objective was to determine the effects of poor maternal nutrition during gestation (over- and restricted-feeding) on the offspring muscle metabolite profile. Pregnant ewes (n = 47) were fed 60% (RES), 100% (CON), or 140% (OVER) of NRC requirements starting at day 30.2 ± 0.2 of gestation. Offspring sample collection occurred at days 90 and 135 of gestation, and within 24 h of birth. C2C12 myoblasts were cultured in serum collected from offspring at birth (n = 18; 6 offspring per treatment) for analysis of oxidative and glycolytic capacity. Unbiased metabolite analysis of longissimus muscle samples (n = 72; 8 fetuses per treatment per time point) was performed using mass spectrometry. Data were analyzed by ANOVA for main effects of treatment, time point, and their interaction. Cells cultured in serum from RES offspring exhibited increased proton leak 49% (p = 0.01) compared with CON, but no other variables of mitochondrial respiration or glycolytic function were altered. Mass spectrometry identified 612 metabolites. Principle component analysis identified day of gestation as the primary driver of metabolic change; however, maternal diet also altered the lipid and amino acid profiles in offspring. The abundance of 53 amino acid metabolites and 89 lipid metabolites was altered in RES compared with CON (p ≤ 0.05), including phospholipids, sphingolipids, and ceramides within the lipid metabolism pathway and metabolites involved in glutamate, histidine, and glutathione metabolism. Similarly, abundance of 63 amino acid metabolites and 70 lipid metabolites was altered in OVER compared with CON (p ≤ 0.05). These include metabolites involved in glutamate, histidine, lysine, and tryptophan metabolism and phosphatidylethanolamine, lysophospholipids, and fatty acids involved in lipid metabolism. Further, the amino acid and lipid profiles diverged between RES and OVER, with 69 amino acid and 118 lipid metabolites differing (p ≤ 0.05) between groups. Therefore, maternal diet affects metabolite abundance in offspring longissimus muscle, specifically metabolites involved in lipid and amino metabolism. These changes may impact post-natal skeletal muscle metabolism, possibly altering energy efficiency and long-term health.

SUN-077 In Utero Growth Restriction Induces an Early Metabolic Shift in Fetal Rat Heart

Adverse uterine environment may expose newborns to develop metabolic diseases later in their life. The in-utero growth restriction (IUGR) is an immediate outcome of a sub-optimal womb environment, where the fetus cannot reach its full growth potential. We have developed an animal model of IUGR based on a low-sodium diet given to dams during the last week of gestation. We showed that the isocaloric low-sodium diet reduces maternal blood volume expansion, causing poor placental perfusion, low placental weight and subsequent IUGR in offspring. Redistribution of blood flow in the fetus was observed, causing a preferential perfusion to major organs, such as the heart. Consistent with this, adult offspring showed an increase in blood pressure and remodeling of cardiomyocytes occurs in adult female, suggesting metabolic changes in cardiac function. In this study, we address whether the IUGR induced-stress leads to metabolic changes in fetal cardiomyocytes to adapt their energy-production process and lipid utilization. At 22 days of gestation, hearts were collected from IUGR and control fetuses, and homogenized. Gene expression profile as well as protein levels were analyzed. We observed an increased expression of critical genes involved in lipid metabolism, such as long chain fatty acid receptor CD36, carnitine palmitoyltransferase CPT1a, and also key enzymes of long chain fatty acid beta-oxidation in IUGR heart. In addition, our results indicate an increase in mitochondrial biogenesis. To address whether changes in lipid metabolite profile might prevail, we performed lipidomic MS analysis in heart homogenates. Lipidomics showed significant accumulation of very long and long-chain fatty acids in the context of IUGR and when comparing males and females. These changes could be reminiscent of an adaptation in the use of fatty acids for energy production. Altogether, these findings suggest that fetal IUGR cardiac cells may rely more on the use of lipids as an energy source, compared to same age control cells. Such alterations in energy metabolism in fetal IUGR cardiomyocytes are consistent with an early metabolic shift to favor lipids as the main energy source. This shift normally occurs in the neonatal life to adapt to an extra-uterine environment. Therefore, our findings suggest that adaptation to an altered placental perfusion results in an early cardiac metabolic remodeling that might predispose individuals to metabolic disorders later in their life. Sources of Research Support: Fond de Recherche Québécois en Santé (FRQS) and Canadian Institutes of Health Research (CIHR).

Abstract 21: Lipid Metabolites Are Associated With Epigenetic Aging Acceleration in the Coronary Artery Risk Development in Young Adults (CARDIA) Study

Background: Epigenetic aging measures including phenotypic aging (PA) and extrinsic epigenetic age acceleration (EEAA) have been associated with age-related diseases and conditions that include cardiovascular diseases, diabetes, and cancer. However, associations between epigenetic aging and lipids have not been widely investigated. Hypothesis: We hypothesized that adverse lipid metabolite profiles are associated with epigenetic age acceleration. Methods: We estimated measures of epigenetic age acceleration in 957 white and black participants from the CARDIA Study with whole-genome blood DNA methylation profiling by the Illumina EPIC array at Year 20 (Y20; ages 38-52). We used separate linear regression models to examine cross-sectional associations of PA and EEAA estimates with fasting triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) levels after adjusting for race, sex, education, alcohol intake, smoking status and physical activity. Results: Participants were 51% female (n=490) and 39% black (n=393) with mean chronological age 45±4 years. Compared with participants in the 1st tertile of TG, those in the 2nd tertile had 1.32 years older PA (95%CI 0.33-2.30) and 1.04 years older EEAA (95%CI 0.22-1.87); those in the 3rd tertile had 1.78 years older PA (95%CI 0.75-2.81) and 1.09 years older EEAA (95%CI 0.23-1.95). Compared to participants in the 1st tertile of HDL-C, those in the 3rd tertile had decreased EEAA by 1.21 years (95%CI -2.16--0.27). There were no significant differences of PA or EEAA among participants of LDL-C tertiles. (Figure 1.) Conclusions: Adverse lipid metabolites (TG and HDL-C) are associated cross-sectionally with accelerated epigenetic aging. Further studies are needed to understand the longitudinal associations between epigenetic aging and adverse lipid profiles as well as the potential mechanisms that underlie these associations.

PLD\u03b11-knockdown soybean seeds display higher unsaturated glycerolipid contents and seed vigor in high temperature and humidity environments

BackgroundSoybean oil constitutes an important source of vegetable oil and biofuel. However, high temperature and humidity adversely impacts soybean seed development, yield, and quality during plant development and after harvest. Genetic improvement of soybean tolerance to stress environments is highly desirable.ResultsTransgenic soybean lines with knockdown of phospholipase Dα1 (PLDα1KD) were generated to study PLDα1′s effects on lipid metabolism and seed vigor under high temperature and humidity conditions. Under such stress, as compared with normal growth conditions, PLDα1KD lines showed an attenuated stress-induced deterioration during soybean seed development, which was associated with elevated expression of reactive oxygen species-scavenging genes when compared with wild-type control. The developing seeds of PLDα1KD had higher levels of unsaturation in triacylglycerol (TAG) and major membrane phospholipids, but lower levels of phosphatidic acid and lysophospholipids compared with control cultivar. Lipid metabolite and gene expression profiling indicates that the increased unsaturation on phosphatidylcholine (PC) and enhanced conversion between PC and diacylglycerol (DAG) by PC:DAG acyltransferase underlie a basis for increased TAG unsaturation in PLDα1KD seeds. Meanwhile, the turnover of PC and phosphatidylethanolamine (PE) into lysoPC and lysoPE was suppressed in PLDα1KD seeds under high temperature and humidity conditions. PLDα1KD developing seeds suffered lighter oxidative stresses than did wild-type developing seeds in the stressful environments. PLDα1KD seeds contain higher oil contents and maintained higher germination rates than the wild-type seeds.ConclusionsThe study provides insights into the roles of PLDα1 in developing soybean seeds under high temperature and humidity stress. PLDα1KD decreases pre-harvest deterioration and enhances acyl editing in phospholipids and TAGs. The results indicate a way towards improving production of quality soybean seeds as foods and biofuels under increasing environmental stress.

Italian cohort of patients affected by inflammatory bowel disease is characterised by variation in glycerophospholipid, free fatty acids and amino acid levels.

Inflammatory bowel disease is a group of pathologies characterised by chronic inflammation of the intestine and an unclear aetiology. Its main manifestations are Crohn's disease and ulcerative colitis. Currently, biopsies are the most used diagnostic tests for these diseases and metabolomics could represent a less invasive approach to identify biomarkers of disease presence and progression. The lipid and the polar metabolite profile of plasma samples of patients affected by inflammatory bowel disease have been compared with healthy individuals with the aim to find their metabolomic differences. Also, a selected sub-set of samples was analysed following solid phase extraction to further characterise differences between pathological samples. A total of 200 plasma samples were analysed using drift tube ion mobility coupled with time of flight mass spectrometry and liquid chromatography for the lipid metabolite profile analysis, while liquid chromatography coupled with triple quadrupole mass spectrometry was used for the polar metabolite profile analysis. Variations in the lipid profile between inflammatory bowel disease and healthy individuals were highlighted. Phosphatidylcholines, lyso-phosphatidylcholines and fatty acids were significantly changed among pathological samples suggesting changes in phospholipase A2 and arachidonic acid metabolic pathways. Variations in the levels of cholesteryl esters and glycerophospholipids were also found. Furthermore, a decrease in amino acids levels suggests mucosal damage in inflammatory bowel disease. Given good statistical results and predictive power of the model produced in our study, metabolomics can be considered as a valid tool to investigate inflammatory bowel disease.

Abstract 3529: Modulation of MDM2 alters the metabolomic programming of dedifferentiated liposarcoma and its sensitivity to cholesterol inhibition

Abstract BACKGROUND: Dedifferentiated liposarcoma (DDLPS) is a highly morbid, mesenchymal tumor characterized by amplification of the 12q chromosomal loci. Although DDLPS are lipid tumors, they produce little lipid. Life expectancy is typically less than 15 months in the advanced setting and standard treatments remain highly toxic. Superior treatment options are clearly needed. Amplification of the MDM2 oncogene that resides in these loci is observed in 100% of all DDLPS; however, to variable levels. Through a negative feedback loop, MDM2 inhibits the tumor suppressive functions of p53 that halts cell growth after cellular stress. Previously, we have reported that MDM2 levels correspond with cellular growth and drug metabolism, but little is known about the effects of MDM2 alterations on global metabolomic profiles. These profiles will help us pinpoint dysregulated pathways that explain, at least partially, the functional effects associated with MDM2 amplification. METHODS: Six DDLPS cell lines were brought directly into culture from patients. MDM2 levels were determined via Western blot and RNA-sequencing. Metabolomics data was generated using the Metabolon platform. Cell viability assays were performed in ZOOM IncuCyte or measured by XTT. Atorvastatin was used to inhibit cholesterol synthesis. MDM2 levels were altered using SAR405838 to raise MDM2 levels and MI-192 to lower MDM2 levels. Synergy was calculated via Chou-Talalay method to determine the combination index (CI) using Compusyn software. RESULTS: MDM2 levels are inversely correlated with metabolites in the lipid and cholesterol pathway (Fisher's, p < 0.001). The lipid metabolism pathway was also the top deregulated pathway (pathway enrichment p-value = 0.03) in transcriptionally profiled DDLPS cell lines treated with MDM2 elevating agent SAR405838. MDM2 low DDLPS cell lines were exquisitely sensitive to HMGA-CoA reductase inhibitors in the low micromolar range. Lipid metabolite profiling of MDM2 low versus high cell lines treated with atorvastatin demonstrated that twice as many lipid metabolites were altered in MDM2 low versus high cells (Chi-square, p < 0.001). MDM2 levels by RNA-seq demonstrated significant correlation between MDM2 gene expression and atorvastatin IC50 doses (r=0.963). MDM2 modulation by use of SAR405838 and MI-192 respectively in combination with atorvastatin displayed antagonism (average CI = 1.5) and synergy (average CI = 0.63), respectively. CONCLUSION: Modulation of MDM2 alters cholesterol metabolism in DDLPS and may serve as druggable target. Citation Format: Bryce Demoret, Andrew Patt, John Hays, Ewy Mathé, James L. Chen. Modulation of MDM2 alters the metabolomic programming of dedifferentiated liposarcoma and its sensitivity to cholesterol inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3529.

Association of Plasma Lipids and Polar Metabolites with Low Bone Mineral Density in Singaporean-Chinese Menopausal Women: A Pilot Study.

The diagnosis of osteoporosis is mainly based on clinical examination and bone mineral density assessments. The present pilot study compares the plasma lipid and polar metabolite profiles in blood plasma of 95 Singaporean-Chinese (SC) menopausal women with normal and low bone mineral density (BMD) using an untargeted metabolomic approach. The primary finding of this study was the association between lipids and femoral neck BMD in SC menopausal women. Twelve lipids were identified to be associated with low BMD by the orthogonal partial least squares (OPLS) model. Plasma concentrations of eight glycerophospholipid, glycerolipid, and sphingolipid species were significantly lower in menopausal women with low BMD but higher in two glycerophospholipid species (phosphatidylinositol and phosphatidic acid). Further, this study found no significant differences in plasma amino acid metabolites. However, trends for lower 4-aminobutyric acid, turanose, proline, aminopropionitrile, threonine, and methionine were found in women with low BMD. This pilot study identified associations between lipid metabolism and femoral neck BMD in SC women. Further studies are required on larger populations for evaluating the bone health effect of these compounds and their usefulness as clinical biomarkers for osteoporosis prediction in women.

3-Hydroxyisobutyryl-CoA hydrolase involved in isoleucine catabolism regulates triacylglycerol accumulation in Phaeodactylum tricornutum.

Since methylmalonyl-CoA epimerase appears to be absent in the majority of photosynthetic organisms, including diatoms, (S)-methylmalonyl-CoA, the intermediate of isoleucine (Ile) catabolism, cannot be metabolized to (R)-methylmalonyl-CoA then to succinyl-CoA. In this study, propionyl-CoA carboxylase (PCC) RNAi silenced strains and 3-hydroxyisobutyryl-CoA hydrolase (HIBCH) overexpression strains were constructed to elucidate the Ile degradation pathway and its influence on lipid accumulation in Phaeodactylum tricornutum based on growth, neutral lipid content and metabolite profile analysis. Knockdown of PCC disturbed the metabolism of Ile through propionyl-CoA to methylmalonyl-CoA, as illustrated by much higher Ile content at day 6. However, Ile decreased to comparable levels to the wild-type at day 10. PCC silencing redirected propionyl-CoA to acetyl-CoA via a modified β-oxidation pathway, and transcript levels for some branched-chain amino acid (BCAA) degradation-related genes, especially HIBCH, significantly upregulated in the PCC mutant, which enhanced the BCAA degradations and thus resulted in higher triacylglycerol (TAG) content. Overexpression of HIBCH accelerates Ile degradation and results in a lowered Ile content in the overexpression strains, thus enhancing carbon skeletons to the tricarboxylic acid cycle and giving rise to increasing TAG accumulation. Our study provides a good strategy to obtain high-lipid-yield transgenic diatoms by modifying the propionyl-CoA metabolism.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'.

Lipidomic profiling of high-fat diet-induced obesity in mice: Importance of cytochrome P450-derived fatty acid epoxides.

OBJECTIVEEnzymatic metabolism of polyunsaturated fatty acids (PUFAs) leads to formation of bioactive lipid metabolites (LMs). Previous studies have shown that obesity leads to deregulation of LMs in adipose tissues. However, most previous studies have focused on single or limited number of LMs, few systematical analyses have been carried out.METHODSWe used a LC-MS/MS-based lipidomics approach, which can analyze >100 LMs produced by cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) enzymes, to analyze profile of LMs in high-fat diet-induced obesity in mice.RESULTSLC-MS/MS showed that dietary feeding of high-fat diet significantly modulated profiles of LMs in adipose tissues. Among the three major PUFA metabolizing pathways (COX, LOX, and CYP), CYP-derived fatty acid epoxides were the most dramatically altered LMs. Almost all types of fatty acid epoxides were reduced by 70–90% in adipose tissues of high-fat diet-fed mice. Consistent with the reduced levels of fatty acid epoxides, the gene expressions of several CYP epoxygenases, including Cyp2j5, Cyp2j6, and Cyp2c44, were significantly reduced in adipose tissues of high-fat diet-fed mice.CONCLUSIONSOur results showed that CYP-derived fatty acid epoxides are the most responsive LMs in high-fat diet-induced obesity, suggesting that these LMs could play critical roles in obesity.

A lipid metabolite profile in atherosclerotic plaques associated with increased inflammation and cardiovascular risk

A lipid metabolite profile in atherosclerotic plaques associated with increased inflammation and cardiovascular risk

Abstract 3987: Prospective serum metabolomic profiles of prostate cancer by size and extent of primary tumor

Abstract Background: Recent studies have identified serum metabolites related to aggressive prostate cancer up to 20 years prior to diagnosis. Lipid and energy metabolites were significantly lower in cases vs. controls, including glycerophospholipids, inositol-1-phosphate, alpha-ketoglutarate, and citrate. To elucidate whether the findings represent an etiologic process or biomarkers of subclinical disease, we focused on differences in the prospective serum metabolomic profiles of men with T2, T3, and T4 prostate cancers. Methods: Clinical data from a nested case-control analysis of prostate cancer in the ATBC Study cohort were examined, including 71 cases diagnosed with T2 primary cancer, 51 with T3, and 15 with T4 (all cases, ages 61-89 years at diagnosis). Median time from fasting serum collection to diagnosis was 10 yr, range 1-20 yr. Cases in each extent of disease category were compared to a common set of 200 non-case controls. Serum samples were analyzed on a high resolution accurate mass platform of ultrahigh performance liquid chromatography/mass spectroscopy and gas chromatography/mass spectroscopy (Metabolon, Inc.), and 654 known metabolites were identified. Unconditional logistic regression models estimated odds ratios (OR) and 95% confidence intervals (CI) for cancer associated with a one standard deviation (1-SD) increment in metabolite concentration. Results: Among the strongest serum metabolite signals for men with T2 prostate cancers were N-acetyl-3-methylhistidine, 2-deoxyuridine, 3-methylhistidine, beta-hydroxyisovalerate, stearoylarachidonoyl-GPPE, and euricoyl-sphingomyelin [1-SD ORs 1.79, 1.71, 1.38, 1.48, 0.73, and 1.48 (p = 0.0002, 0.005, 0.01, 0.02, 0.02, and 0.02), respectively]. Men diagnosed with T3 cancer exhibited a lipid metabolite profile most similar to that previously reported for aggressive disease, with top metabolite signals being for oleoyl-linoleoyl-GPPI, palmitoyl-linoleoyl-GPPI, cholate, inositol-1-phosphate, stearoyl-sphingomyelin, and 4-imidazoleacetate (ORs 0.49, 0.56, 0.57, 0.60, 1.54, and 1.59 (p = 0.00002, 0.001, 0.002, 0.003, 0.01, and 0.01), respectively). Men with more extensive T4 cancers showed secondary bile acid and caffeine metabolite associations including orotate, taurodeoxycholate, glycodeoxycholate, caffeine, 4-imidazoleacetate, 1,3,7-trimethylurate, and deoxycholate (ORs 0.40, 2.62, 3.19, 2.40, 2.52, 2.31, and 3.31 (p = 0.004, 0.007, 0.007, 0.01, 0.01, 0.02, and 0.02), respectively). Conclusions: In this analysis, men with T2, T3, and T4 prostate cancer primaries exhibited qualitative differences in their serum metabolite profiles years in advance of the clinical diagnoses. Whether these differences represent novel biomarkers related to greater primary tumor mass that individual patients might “transition” through while still undiagnosed is unknown but testable through additional clinical series. Citation Format: Demetrius Albanes, Stephanie J. Weinstein, Alison M. Mondul. Prospective serum metabolomic profiles of prostate cancer by size and extent of primary tumor. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3987.