Levels Of Stearoyl CoA Desaturase Research Articles

Fatty acid profiles and Delta9 desaturase (stearoyl-CoA desaturase; SCD 1) expression in adipose tissue surrounding benign and malignant breast tumors

The progression of tumors occurs through interactions between the tumor and the stroma. Understanding the role of adipose tissue (AT), as the main component of the breast tumor microenvironment (TME) in the development of cancer, is crucial for the early detection of breast cancer (BC). This study compared the FA profiles, desaturase index (DI), and stearoyl CoA desaturase 1 (SCD1) mRNA levels in the AT that surrounds tumors in women with BC and benign breast disease (BBD). Specimens were collected from 40 Iranian women who had undergone breast surgery. These women were age- and BMI-matched and were divided into two groups: BC (n = 20) and BBD (n = 20). Gas chromatography and quantitative real-time PCR were used to analyze the FA profiles and SCD1 mRNA levels, respectively. The DI was calculated by dividing the amounts of monounsaturated FAs by the amount of saturated FA. There were no significant differences in age and BMI between women with BC and BBD. The FA profiles and DI were also similar in both groups. However, mRNA levels of SCD1 were found to be 5 times higher in the breast AT of BC than in the breast AT of BBD (p < 0.0001). We showed that SCD1 was significantly upregulated in the AT surrounding BC tumors, even though the DI and FA profiles were unchanged compared to those in the AT of BBD patients. It is important to note that the breast AT of women with BBD has previously been overlooked and warrants further studies.

MiR-3180 inhibits hepatocellular carcinoma growth and metastasis by targeting lipid synthesis and uptake

PurposeReprogrammed lipid metabolism is a hallmark of cancer that provides energy, materials, and signaling molecules for rapid cancer cell growth. Cancer cells acquire fatty acids primarily through de novo synthesis and uptake. Targeting altered lipid metabolic pathways is a promising anticancer strategy. However, their regulators have not been fully investigated, especially those targeting both synthesis and uptake.MethodsImmunohistochemistry was performed on samples from patients with hepatocellular carcinoma (HCC) to establish the correlation between miR-3180, stearoyl-CoA desaturase-1 (SCD1), and CD36 expression, quantified via qRT-PCR and western blotting. The correlation was analyzed using a luciferase reporter assay. Cell proliferation, migration, and invasion were analyzed using CCK-8, wound healing, and transwell assays, respectively. Oil Red O staining and flow cytometry were used to detect lipids. Triglycerides and cholesterol levels were analyzed using a reagent test kit. CY3-labeled oleic acid transport was analyzed using an oleic acid transport assay. Tumor growth and metastasis were detected in vivo in a xenograft mouse model.ResultsMiR-3180 suppressed de novo fatty acid synthesis and uptake by targeting the key lipid synthesis enzyme SCD1 and key lipid transporter CD36. MiR-3180 suppressed HCC cell proliferation, migration, and invasion in an SCD1- and CD36-dependent manner in vitro. The mouse model demonstrated that miR-3180 inhibits HCC tumor growth and metastasis by inhibiting SCD1- and CD36-mediated de novo fatty acid synthesis and uptake. MiR-3180 expression was downregulated in HCC tissues and negatively correlated with SCD1 and CD36 levels. Patients with high miR-3180 levels showed better prognosis than those with low levels.ConclusionsOur investigation indicates that miR-3180 is a critical regulator involved in de novo fatty acid synthesis and uptake, which inhibits HCC tumor growth and metastasis by suppressing SCD1 and CD36. Therefore, miR-3180 is a novel therapeutic target and prognostic indicator for patients with HCC.

The Impact of the Hippo Pathway and Cell Metabolism on Pathological Complete Response in Locally Advanced Her2+ Breast Cancer: The TRISKELE Multicenter Prospective Study.

Simple SummaryPathological complete response (pCR) is a key outcome in locally advanced Her2+ breast cancer (BC) patients treated with anti-Her2−based neoadjuvant therapy. Several clinical and biological features may affect pCR rate, but reliable predictors are needed for clinical practice. The Hippo pathway and its main transducers, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), play a relevant role in treatment outcomes. We herein present evidence concerning the impact of the immunohistochemical expression of key Hippo transducers and their regulators, namely AMP-activated protein kinase (AMPK), Stearoyl-CoA-desaturase 1 (SCD1), and HMG-CoA reductase (HMGCR), on the pCR rate of 65 Her2+ BC patients receiving neoadjuvant trastuzumab-based therapy. Low expression of TAZ, especially if concomitant with low expression of YAP and HMGCR and high expression of SCD1, was a negative predictor of pCR, although not confirmed in the multivariate analysis. However, our findings were concordant with overall survival data from the TCGA cohort.The Hippo pathway and its two key effectors, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), are consistently altered in breast cancer. Pivotal regulators of cell metabolism such as the AMP-activated protein kinase (AMPK), Stearoyl-CoA-desaturase 1 (SCD1), and HMG-CoA reductase (HMGCR) are relevant modulators of TAZ/YAP activity. In this prospective study, we measured the tumor expression of TAZ, YAP, AMPK, SCD1, and HMGCR by immunohistochemistry in 65 Her2+ breast cancer patients who underwent trastuzumab-based neoadjuvant treatment. The aim of the study was to assess the impact of the immunohistochemical expression of the Hippo pathway transducers and cell metabolism regulators on pathological complete response. Low expression of cytoplasmic TAZ, both alone and in the context of a composite signature identified by machine learning including also low nuclear levels of YAP and HMGCR and high cytoplasmic levels of SCD1, was a predictor of residual disease in the univariate logistic regression. This finding was not confirmed in the multivariate model including estrogen receptor > 70% and body mass index > 20. However, our findings were concordant with overall survival data from the TCGA cohort. Our results, possibly affected by the relatively small sample size of this study population, deserve further investigation in adequately sized, ad hoc prospective studies.

Voluntary exercise training improves body weight of leptin-deficient ob/ob mice by altering hepatic stearoyl-CoA desaturase 1 and deleted in breast cancer 1 protein levels.

[Purpose]Deleted in breast cancer 1 (DBC1) ablation causes obesity, and stearoyl-CoA desaturase 1 (SCD1) induces the biosynthesis of monounsaturated fatty acids. This study examined whether voluntary wheel running (VWR) alters SCD-1 and DBC1 protein levels in the liver of leptin-deficient ob/ob mice.[Methods]Twenty-five Ob/Ob mice were divided into two groups (ob/ob-Sed and ob/ob-Ex). The expression of DBC1 and SCD1 in the mouse liver was determined using western blotting.[Results]After 10 weeks, VWR significantly reduced body weight without affecting the fatty acid synthase and CD36 protein levels. The average daily running distance was 4.0±1.0 km/day. This improvement was associated with changes in the hepatic SCD1 and DBC1 levels. Hepatic SCD-1 protein levels increased significantly, and DBC1 protein levels decreased in ob/ob-Sed animals. On the other hand, VWR inhibited the obesity-induced increase in SCD1 expression and impaired the obesity-induced decrease in DBC1 expression in the liver of leptin-deficient ob/ob mice.[Conclusion]This is the first study showing that VWR has strong effects on hepatic SCD1 and DBC1 in ob/ob mice, and provides key insights into the effects of exercise on obesity.

Increased lipogenesis is critical for self-renewal and growth of breast cancer stem cells: Impact of omega-3 fatty acids.

Aberrant lipid metabolism has recently been recognized as a new hallmark of malignancy, but the characteristics of fatty acid metabolism in breast cancer stem cells (BCSC) and potential interventions targeting this pathway remain to be addressed. Here, by using the in vitro BCSC models, mammosphere‐derived MCF‐7 cells and HMLE‐Twist‐ER cells, we found that the cells with stem cell‐like properties exhibited a very distinct profile of fatty acid metabolism compared with that of their parental cancer cells, characterized by increased lipogenesis, especially the activity of stearoyl‐CoA desaturase 1 (SCD1) responsible for the production of monounsaturated fatty acids, and augmented synthesis and utilization of the omega‐6 arachidonic acid (AA). Suppression of SCD1 activity by either enzyme inhibitors or small interfering RNA (siRNA) knockdown strikingly limited self‐renewal and growth of the BCSC, suggesting a key role for SCD1 in BCSC proliferation. Furthermore, elevated levels of SCD1 and other lipogenic enzymes were observed in human breast cancer tissues relative to the noncancer tissues from the same patients and correlated with the pathological grades. Interestingly, treatment of BCSC with omega‐3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, effectively downregulated the expression of the lipogenic enzymes and markedly suppressed BCSC self‐renewal and growth. Dietary supplementation of nude mice bearing BCSC‐derived tumors with omega‐3 fatty acids also significantly reduced their tumor load. These findings have demonstrated that increased lipogenesis is critical for self‐renewal and growth of BCSC, and that omega‐3 fatty acids are effective in targeting this pathway to exert their anticancer effect.

Steroid-depleted endometriosis serum improves oocyte maturation in IVM systems.

In vitro maturation (IVM) is a novel approach to overcome the adverse effects of human in vitro fertilization (IVF). The aim of the present study is to evaluate the effect of total and steroid-depleted serum obtained from patients with endometriosis on IVM outcome as supplementation for this system. To this purpose, patients with endometriosis were selected according to in/excluding criteria. Germinal vesicles (GVs) and cumulus cells were treated with 10% of each serum. The expression levels of stearoyl CoA desaturase 1 (SCD 1) and cyclooxygenase-2 (COX-2) genes were evaluated by RT-qPCR. Gas-liquid chromatography and flow cytometry were performed to analyze fatty acids composition and apoptosis. The mRNA expression levels of SCD1 (2.47 fold) and COX-2 (6.4 fold), and also the synthesis of oleate, linoleate, and arachidonate were increased (1.19, 1.06, and 2.37 folds, respectively) in cumulus cells treated with steroid-depleted serum (p < .05). The synthesis of palmitate, palmitoleate, and stearate (0.995, 0.67, and 0.7 folds, respectively) and also the rate of apoptosis were significantly decreased in these cells (p < .05). Moreover, GVs cultured in steroid-depleted group showed a significantly higher rate of maturation (p < .001). Overall, our findings imply a new insight into the expansion of IVM system in oocytes development.

Stearoyl-CoA Desaturase-1 Enzyme Inhibition by Grape Skin Extracts Affects Membrane Fluidity in Human Colon Cancer Cell Lines.

The polyphenolic compounds present in grape extracts have chemopreventive and anticancer properties. Here, we studied the ability of two grape skin extracts (GSEs), Autumn Royal and Egnatia, to influence the cell motility and membrane fluidity regulated by the enzyme Stearoyl-CoA desaturase-1 (SCD1) which increases with the cancer aggressiveness. Caco2 and SW480 human colon cancer cell lines were treated with increasing concentrations of GSEs to evaluate cell proliferation and motility. SCD1 levels were evaluated in both treated cell lines, by membrane lipidomic analysis conducted by gas chromatography. The expression levels of SCD1 and other factors involved in the reorganization of the cytoskeleton and focal adhesions were assessed by Real-time PCR, Western Blotting, and Immunofluorescence staining. High-performance liquid chromatography (HPLC) analyses were performed to determine the phenolic composition in the GSEs, finding them more expressed in Autumn Royal than in Egnatia. Both treatments reduced the levels of SCD1, phospho-Rac1/Cdc42/Rac1/Cdc42 ratio, Cofilin, Vimentin, and phospho-Paxillin especially in Caco2 compared to SW480, showing a different behavior of the two cell lines to these natural compounds. Our findings show that GSEs block the cell migration and membrane fluidity through a new mechanism of action involving structural cellular components.

Improvement in High-fat Diet-induced Obesity and Insulin Resistance upon Uptake of PS-B1, a Fermented Product Prepared from Soy Flour Using Lactic Acid Bacteria

PS-B1 is a fermented product prepared from soy flour using lactic acid bacteria. Over a 10-week period, C57BL/6J mice were reared under laboratory conditions on a normal diet (control, n=5), high-fat diet (HF, n=5), or high-fat diet supplemented with 4% PS-B1 (HF-P, n=6). After 10 weeks, the change in weight gain, intestinal and epididymal fat accumulation, serum and liver biochemical parameters, and gene expression in the mice was investigated. HF diet-induced weight gain and increase in intestinal and epididymal fat accumulation were lower in mice fed with HF-P diet than in mice fed with HF diet, suggesting that PS-B1 prevented HF diet-induced obesity in HF-P mice. Furthermore, the levels of liver lipids (triglycerides, TG; non-esterified fatty acid, NEFA; total cholesterol, TC), serum TC, serum glucose, and serum insulin were significantly increased in the HF group than those in control mice. In HF-P mice, neither serum TC nor serum glucose levels were reduced. In contrast, the levels of liver lipids and serum insulin were lower in HF-P mice than in HF mice, suggesting that PS-B1 reduced these parameters in HF-P mice. The homeostatic model assessment of insulin resistance (HOMA-IR) value, which was calculated from the serum glucose and insulin levels, was 21.5 ± 4.2 in the HF mice. However, the HOMA-IR (8.2 ± 0.2) values were significantly decreased in the HF-P mice, suggesting that PS-B1 improves insulin resistance. Additionally, we compared the expression levels of stearoyl-CoA desaturase-1 (Scd1) in the liver. Quantitative RT-PCR showed increased expression of Scd1 in HF mice compared to that in control mice. Furthermore, ingestion of PS-B1 led to reduced expression of Scd1 mRNA in HF-P mice, implying that PS-B1 is effective in reducing the expression of the gene encoding SCD1. These results suggest that the anti-obesity effect of PS-B1 and improvement in fat accumulation upon PS-B1 uptake may be due to improvement in insulin resistance and reduction in the expression level of Scd1.

Effect of Breed on Transcriptional and Protein Expression of Lipogenic Enzymes in Tail and Subcutaneous Adipose Tissue from Two Grazing Breeds of Lambs.

Simple SummaryAn experiment to determine the effect of sheep breed on subcutaneous fatty acid composition was carried out at the Butalcura Research Station, Chiloé, Chile. To this end, two breeds of lambs were challenged to graze a typical, naturalized pasture of the Chiloé Archipelago, Chile, from 60 d to 120 d after birth. The animals were sacrificed to collect samples from subcutaneous fat (SCF) from the back, and tail fat (TF) to determine the effect of breed on transcriptional expression of lipogenic enzymes and fatty acid profile in these two fat depots. The results showed that although mRNA expression of enzymes was similar in both breeds, there were differences in certain protein levels in the SCF, partially related with the fatty acid profiles, thus affecting the selection of lamb breed either for human consumption or experimental purposes.This experiment was carried out to determine the effect of breed on mRNA and protein expression levels of lipogenic enzymes acetyl-CoA carboxylase α (ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase 1 (SCD1) plus sterol regulatory element binding transcription factor 1c (SREBP1c) in the subcutaneous fat (SCF) from the back of the animal, and tail fat (TF) of both Chilota and Suffolk Down lambs grazing Calafatal. Eight Chilota and six Suffolk Down 2-month-old male lambs were allocated to graze a “Calafatal”, a typical secondary succession of Chiloé Archipelago, Chile. After 62 d, lambs were slaughtered according to Chile’s meat industry standards. Fatty acid profile, RT-qPCR, and Western blot analyses from SCF and TF samples were performed. Although the mRNA expression levels of ACC, FAS, SCD1 and SREBP1c in SCF did not differ significantly between breeds (p > 0.05), a trend to higher mRNA expression of FAS and SREBP1c in TF from Chilota lambs was observed (p = 0.06). On the other hand, FAS levels in SCF were higher in Chilota than in Suffolk Down lambs (p < 0.02), although Suffolk Down showed higher fat contents and saturated fatty acid (SFA) proportions than Chilota lambs (p < 0.01). The FAS protein expression in TF was similar in both breeds (p > 0.05). Although the fat content was higher in Suffolk Down than in Chilota lambs (p < 0.01), the SFA proportions were similar in both breeds. Finally, it can be concluded that although mRNA expression of enzymes was similar in both breeds, there were differences in some protein levels in the SCF, partially related with the fatty acid profiles, thus affecting the selection of lamb breed either for human consumption or experimental purposes.

Maternal high-fat diet during suckling programs visceral adiposity and epigenetic regulation of adipose tissue stearoyl-CoA desaturase-1 in offspring.

The lactation-suckling period is critical for white adipose tissue (WAT) development. Early postnatal nutrition influences later obesity risk but underlying mechanisms remain elusive. Here, we tested whether altered postnatal nutrition specifically during suckling impacts epigenetic regulation of key metabolic genes in WAT and alter long-term adiposity set point. We analyzed the effects of maternal high-fat (HF) feeding in rats exclusively during lactation-suckling on breast milk composition and its impact on male offspring visceral epidydimal (eWAT) and subcutaneous inguinal (iWAT) depots during suckling and in adulthood. Maternal HF feeding during lactation had no effect on mothers' body weight (BW) or global breast milk composition, but induced qualitative changes in breast milk fatty acid (FA) composition (high n-6/n-3 polyunsaturated FA ratio and low medium-chain FA content). During suckling, HF neonates showed increased BW and mass of both eWAT and iWAT depot but only eWAT displayed an enhanced adipogenic transcriptional signature. In adulthood, HF offspring were predisposed to weight gain and showed increased hyperplastic growth only in eWAT. This specific eWAT expansion was associated with increased expression and activity of stearoyl-CoA desaturase-1 (SCD1), a key enzyme of FA metabolism. SCD1 converts saturated FAs, e.g. palmitate and stearate, to monounsaturated FAs, palmitoleate and oleate, which are the predominant substrates for triglyceride synthesis. Scd1 upregulation in eWAT was associated with reduced DNA methylation in Scd1 promoter surrounding a PPARγ-binding region. Conversely, changes in SCD1 levels and methylation were not observed in iWAT, coherent with a depot-specific programming. Our data reveal that maternal HF feeding during suckling programs long-term eWAT expansion in part by SCD1 epigenetic reprogramming. This programming events occurred with drastic changes in breast milk FA composition, suggesting that dietary FAs are key metabolic programming factors in the early postnatal period.

Vitamin A deficiency increases the oleic acid (C18:1) levels in the kidney of high fructose diet-fed rats.

Background & objectives:Stearoyl-CoA desaturase 1 (SCD1) is a key lipogenic enzyme responsible for endogenous synthesis of monounsaturated fatty acids (MUFA) and plays a key role in various pathophysiology, including fatty liver diseases. In this experimental study the impact of vitamin A deficiency was assessed on SCD1 regulation in relation to kidney biology, under high fructose (HFr) diet-fed condition in rats.Methods:Forty male weanling (21 day old) Wistar rats were divided into four groups control, vitamin A-deficient (VAD), HFr, VAD with HFr consisting of eight rats each, except 16 for the VAD group. The groups received one of the following diets: control, VAD, HFr and VAD with HFr for 16 wk, except half of the VAD diet-fed rats were shifted to HFr diet, after eight week period.Results:Feeding of VAD diet (alone or with HFr) significantly reduced the kidney retinol (0.51, 0.44 μg/g vs. 2.1 μg/g; P<0.05), while increased oleic (C18:1) and total MUFA levels (23.3, 22.2% and 27.3, 25.4% respectively vs. 14.7 and 16.6%; P<0.05) without affecting the SCD1, both at protein and mRNA levels, when compared with HFr. Comparable, immunohistological staining for SCD1 was observed in the distal convoluted tubules. Despite an increase in MUFA, morphology, triglyceride content and markers of kidney function were not affected by VAD diet feeding.Interpretation & conclusions:Feeding of VAD diet either alone or under HFr condition increased the kidney oleic acid (C18:1) levels and thus total MUFA, which corroborated with elevated SCD1 activity index, without affecting its expression status. However, these changes did not alter the kidney morphology and function. Thus, nutrient-gene regulation in kidney biology seems to be divergent.

Long-term administration of olanzapine induces adiposity and increases hepatic fatty acid desaturation protein in female C57BL/6J mice.

Objective(s):Weight gain and metabolic disturbances such as dyslipidemia, are frequent side effects of second-generation antipsychotics, including olanzapine. This study examined the metabolic effects of chronic olanzapine exposure. In addition, we investigated the hepatic fatty acid effects of olanzapine in female C57BL/6J mice fed a normal diet.Materials and Methods:Female C57BL/6J mice orally received olanzapine or normal saline for 7 weeks. The effects of long-term olanzapine exposure on body weight changes, food efficiency, blood glucose, triglyceride (TG), insulin, and leptin levels were observed. Hepatic TG and abdominal fat mass were investigated, and fat cell morphology was analyzed through histopathological methods. The levels of protein markers of fatty acid regulation in the liver, namely fatty acid synthase (FAS) and stearoyl-CoA desaturase-1 (SCD-1), were measured.Results:Olanzapine treatment increased the food intake of the mice as well as their body weight. Biochemical analyses showed that olanzapine increased blood TG, insulin, leptin, and hepatic TG. The olanzapine group exhibited increased abdominal fat mass and fat cell enlargement in abdominal fat tissue. Western blotting of the mouse liver revealed significantly higher (1.6-fold) levels of SCD-1 in the olanzapine group relative to the control group; by contrast, FAS levels in the two groups did not differ significantly.Conclusion:Enhanced lipogenesis triggered by increased hepatic SCD-1 activity might be a probable peripheral mechanism of olanzapine-induced dyslipidemia. Some adverse metabolic effects of olanzapine may be related to the disturbance of lipid homeostasis in the liver.

Vitamin A deficiency induces endoplasmic reticulum stress and apoptosis in pancreatic islet cells: Implications of stearoyl-CoA desaturase 1-mediated oleic acid synthesis

Previously, we reported that vitamin A deficiency resulted in the reduction of stearoyl-CoA desaturase 1 (SCD1) and monounsaturated fatty acid (MUFA) levels, which corroborated with attenuation of high fructose-induced hepatic steatosis. Here, we aimed at assessing the effect of vitamin A deficiency on SCD1, MUFA levels and their impact on pancreas’ structure and functions. Male weanling Wistar rats fed one of the four diets, namely control (Con), vitamin A-deficient (VAD), highfructose (HFr) and vitamin A-deficient diet with highfructose (VADHFr) for 16 weeks period. Compared to the control, feeding of VAD diet (alone or with HFr) resulted in pancreatic intra-islet vessel dilation and reduced plasma insulin, glucagon and C-peptide levels, however, glucose levels decreased only in VADHFr group. In line with plasma levels, VAD diet-fed animals displayed lower immunostaining for insulin and glucagon, which corroborated with increased apoptotic staining observed in the islet regions, possibly due to increased cellular stress, as indicated by high immunostaining for endothelial nitric oxide synthase (eNOS) and CCAAT/Enhancer-binding protein homologues protein (CHOP). On the other hand, it significantly decreased the SCD1 protein, which corroborated with reduced MUFA levels, particularly, oleic acid (C18:1), when compared to the control and HFr groups. In conclusion, chronic vitamin A deficiency altered the structure and functions of pancreas by diminishing the islet cells, possibly by inducing cellular stress-mediated apoptosis and decreasing SCD1-mediated oleic acid (C18:1) synthesis. Thus, the data suggest that unlike liver, the reduction in SCD1 and MUFA levels in the pancreas exerts deleterious effects on its functions and perturb the overall cellular metabolism.

MiR-212-5p suppresses lipid accumulation by targeting FAS and SCD1.

MicroRNAs, a class of small noncoding RNAs, are implicated in controlling a variety of biological processes. We have shown that leucine deprivation suppresses lipogenesis by inhibiting fatty acid synthase (FAS) expression in the liver previously; the aim of our current study is to investigate which kind of microRNA is involved in the regulation of FAS expression in response to leucine deprivation. Here, we indicated that microRNA-212-5p specifically binds to mouse FAS 3'UTR and inhibits its activity. Leucine deficiency significantly increased the mRNA levels of miR-212-5p in the livers of mice. Further studies proved that miR-212-5p also directly binds to the 3'UTR of stearoyl-CoA desaturase-1 (SCD1) to inhibit its activity. Overexpression of miR-212-5p decreases the protein levels of FAS and SCD1 in vitro and in vivo, and silencing of miR-212-5p has the opposite effects in mouse primary hepatocytes. Moreover, overexpression of miR-212-5p significantly decreases triglyceride (TG) accumulation in primary hepatocytes and in the livers of mice injected with adenovirus-mediated overexpressing of miR-212-5p (Ad-miR-212). Interestingly, inhibition of miR-212-5p reverses the suppressive effects of leucine deficiency on FAS and SCD1 expression, as well as TG accumulation in mouse primary hepatocytes. Finally, we demonstrate that leucine deficiency induces the expression of miR-212-5p in a GCN2/ATF4-dependent manner. Taken together, our results demonstrate a novel function of hepatic miR-212-5p in the regulation of lipid metabolism which represents a potential therapeutic target for the treatment of non-alcohol fatty liver diseases (NAFLD).

Stearoyl-CoA-desaturase 1 regulates lung cancer stemness via stabilization and nuclear localization of YAP/TAZ.

Recent evidences suggest that stearoyl-CoA-desaturase 1 (SCD1), the enzyme involved in monounsaturated fatty acids synthesis, has a role in several cancers. We previously demonstrated that SCD1 is important in lung cancer stem cells survival and propagation. In this article, we first show, using primary cell cultures from human lung adenocarcinoma, that the effectors of the Hippo pathway, Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), are required for the generation of lung cancer three-dimensional cultures and that SCD1 knock down and pharmacological inhibition both decrease expression, nuclear localization and transcriptional activity of YAP and TAZ. Regulation of YAP/TAZ by SCD1 is at least in part dependent upon β-catenin pathway activity, as YAP/TAZ downregulation induced by SCD1 blockade can be rescued by the addition of exogenous wnt3a ligand. In addition, SCD1 activation of nuclear YAP/TAZ requires inactivation of the β-catenin destruction complex. In line with the in vitro findings, immunohistochemistry analysis of lung adenocarcinoma samples showed that expression levels of SCD1 co-vary with those of β-catenin and YAP/TAZ. Mining available gene expression data sets allowed to observe that high co-expression levels of SCD1, β-catenin, YAP/TAZ and downstream targets have a strong negative prognostic value in lung adenocarcinoma. Finally, bioinformatics analyses directed to identify which gene combinations had synergistic effects on clinical outcome in lung cancer showed that poor survival is associated with high co-expression of SCD1, β-catenin and the YAP/TAZ downstream target birc5. In summary, our data demonstrate for the first time the involvement of SCD1 in the regulation of the Hippo pathway in lung cancer, and point to fatty acids metabolism as a key regulator of lung cancer stem cells.

Drug Redeployment to Kill Leukemia and Lymphoma Cells by Disrupting SCD1-Mediated Synthesis of Monounsaturated Fatty Acids

The redeployed drug combination of bezafibrate and medroxyprogesterone acetate (designated BaP) has potent in vivo anticancer activity in acute myelogenous leukemia (AML) and endemic Burkitt lymphoma (eBL) patients; however, its mechanism-of-action is unclear. Given that elevated fatty acid biosynthesis is a hallmark of many cancers and that these drugs can affect lipid metabolism, we hypothesized that BaP exerts anticancer effects by disrupting lipogenesis. We applied mass spectrometry-based lipidomics and gene and protein expression measurements of key lipogenic enzymes [acetyl CoA carboxylase 1 (ACC1), fatty acid synthase (FASN), and stearoyl CoA desaturase 1 (SCD1)] to AML and eBL cell lines treated with BaP. BaP treatment decreased fatty acid and phospholipid biosynthesis from (13)C D-glucose. The proportion of phospholipid species with saturated and monounsaturated acyl chains was also decreased after treatment, whereas those with polyunsaturated chains increased. BaP decreased SCD1 protein levels in each cell line (0.46- to 0.62-fold; P < 0.023) and decreased FASN protein levels across all cell lines (0.87-fold decrease; P = 1.7 × 10(-4)). Changes to ACC1 protein levels were mostly insignificant. Supplementation with the SCD1 enzymatic product, oleate, rescued AML and e-BL cells from BaP cell killing and decreased levels of BaP-induced reactive oxygen species, whereas supplementation with the SCD1 substrate (and FASN product), palmitate, did not rescue cells. In conclusion, these data suggest that the critical anticancer actions of BaP are decreases in SCD1 levels and monounsaturated fatty acid synthesis. To our knowledge, this is the first time that clinically available antileukemic and antilymphoma drugs targeting SCD1 have been reported.

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.

Visceral and subcutaneous adipose tissue stearoyl‐CoA desaturase‐1 mRNA levels and fatty acid desaturation index positively correlate with BMI in morbidly obese women

The aim of this study was to re‐evaluate possible associations between BMI and (1) stearoyl‐CoA desaturase‐1 (SCD1) gene expression in adipose tissue; (2) adipose tissue or serum lipids oleic acid/stearic acid (18:1/18:0) desaturation index (DI); and (3) expression of less studied SCD isoform SCD5 in adipose tissue of obese patients. SCD1 and SCD5 mRNA levels in adipose tissue from 16 morbidly obese women were analyzed by RT‐PCR. Fatty acid composition of adipose tissue and whole serum lipids were determined with gas chromatography‐mass spectrometry. The SCD1 mRNA levels, as well as 18:1/18:0 DI in adipose tissue, correlated positively with BMI in obese patients. A weak positive association between the serum lipid 18:1/18:0 DI and BMI did not reach the threshold of statistical significance. The SCD5 mRNA levels in adipose tissue were approximately 400 times lower than the SCD1 levels and did not correlate with BMI. Positive correlations between BMI and visceral or subcutaneous adipose tissue 18:1/18:0 DI were stronger than the association between serum whole lipid 18:1/18:0 DI and BMI in morbidly obese women. The expression of the SCD1 gene in human adipose tissue is markedly stronger than the expression of the SCD5 gene.Practical applications: Our findings confirm previous suggestions that SCD1 may serve as an attractive therapeutic target in patients with obesity and related disorders.Oleic acid/stearic acid (18:1/18:0) desaturation index (DI) in adipose tissue of obese subjects reflects the level of SCD1 gene expression in adipose tissue. Positive correlations between BMI and adipose tissue DI were stronger than the association between serum whole lipid DI and BMI in morbidly obese women.

Stearoyl-CoA desaturase 1 and paracrine signal involvement in the promotion of breast cancer cell migration induced by cancer-associated fibroblasts

Despite the acknowledged impact of the tumor stroma on breast cancer development and progression, the molecular basis of such effects remain partially unexplained. We previously reported that breast cancer-associated fibroblasts (CAFs) induced epithelial-mesenchymal transition and an increase in cell membrane fluidity and migration speed in poorly (MCF-7) and highly invasive (MDA-MB-231) breast cancer cells. More recently, in order to better define the mechanisms responsible for the CAF-promoted tumor cell migration, we investigated the role of Stearoyl-CoA desaturase 1 (SCD1), the main enzyme regulating membrane fluidity, and demonstrated its CAF-triggered up-regulation as well as its crucial role in the migratory ability of the above tumor cells. Besides SCD1 induction, a CAF-promoted enhancement in the protein level and/or activity of the SCD1 transcription factor, the sterol regulatory element-binding protein 1 (SREBP1), was observed. Moreover, the influence of stroma-derived signals in cancer cell migration speed was proved by cell tracking analysis in the presence of neutralizing antibodies to hepatocyte growth factor, transforming growth factor-β or basic fibroblast growth factor, where a marked reduction or abolishment of the fibroblast-triggered increase in cancer cell migration speed was observed. In the last part of this study, in order to verify if soluble CAF-derived factors stimulate breast cancer cell migration in a SCD1-dependent manner, tumor cells were exposed to CAF-conditioned medium (CM) and their migration evaluated by scratch assay in the presence of a small molecule inhibitor of SCD1. Moreover, to assess if the induction of SCD1 expression by CAFs might occur via SREBP1, the desaturase levels were also determined in SREBP1-inhibited tumor cells. These latest investigations indicate that SCD1 contributes to the promotion of breast cancer cell migration by CAF-derived soluble factors, since the desaturase inhibition completely suppressed the stimulatory effect of CAF-CM on tumor cell migration. SREBP1 inhibition impaired CAF-mediated up-regulation of SCD1 in poorly invasive but not in highly invasive tumor cells, in which SREBP1-independent mechanisms may account for the enhancement of SCD1 levels. These results provide further insights in understanding the role of CAFs in promoting tumor cell migration, which may help to design new stroma-based therapeutic strategies.

Abstract 2443: Novel role of glucose-regulated protein 78 mediating lipid metabolism through controlling stearoyl-CoA desaturase 1

Abstract Over 230,000 new cases of invasive breast cancer are diagnosed annually within the United States. Of these cases, 70% express the estrogen receptor-α and may be treated with antiestrogens or aromatase inhibitors. While these drugs exhibit clinical benefits, over 50% will develop or not respond to antiestrogen therapy, making understanding the molecular mechanism of antiestrogen resistance critical to preventing and treating endocrine resistant breast cancer. Recently, we have determined a key role of the unfolded protein response endoplasmic reticulum (EnR) protein chaperone, glucose regulated protein 78 (GRP78), in mediating antiestrogen resistance. A sole designation of GRP78 as a protein chaperone controlling UPR signaling is limiting because GRP78 is multifunctional. We now expand the role of GRP78 to include its novel actions regulating lipid metabolism. Metabolic analysis of antiestrogen sensitive LCC1 and antiestrogen resistant LCC9 breast cancer cells indicate that inhibition of GRP78 through RNAi results in an increase in the intracellular concentrations of the polyunsaturated fats (PUFA) linoleate (18:2n6), linolenate [alpha or gamma; (18:3n3 or 6)], dihomo-linolenate (20:3n3 or n6), and dihomo-linoleate (20:2n6). GRP78 knockdown results in an increase in delta-6 desaturase in the LCC9 cells corresponding with the observed increase in PUFA. Moreover, knockdown of GRP78 decreased stearoyl-CoA desaturase 1 (SCD1) and fatty acid synthase (FASN) protein levels, further supporting a role for GRP78 in lipid metabolism. Treatment of breast cancer cells with increasing doses of PUFA linoleic acid results in the inhibition of SCD1, suggesting that GRP78 regulation of PUFA metabolism mediates GRP78 actions on SCD1 and lipid biogenesis. Antiestrogen resistant cells express higher levels of SCD1. Moreover, elevated SCD1 is associated with breast cancer reoccurrence and reduced survival in breast cancer patient-derived data sets, suggesting a critical role of SCD1 in mediating antiestrogen resistance. LCC9 orthotopic tumors treated with GRP78 targeting morpholino were re-sensitized to tamoxifen. Targeting GRP78 in vivo resulted in reduced SCD1 protein in GRP78 morpholino+tamoxifen treated tumors, demonstrating a key role of GRP78/SCD1 interaction in drug resistance. Inhibition of GRP78 also increased short-chained acyl-CoA dehydrogenase (ACADS) protein expression and decreased the fatty acid metabolite butyrylcarnitine, indicating a stimulation of beta-oxidation. These data suggest that the effect of GRP78 knockdown on fatty acid metabolism and biogenesis may represent a new homeostatic ability of GRP78 to modify fatty acid metabolism. The consequences of these activities may help reduce EnR stress by providing an additional energy source for protein folding/refolding and so help alleviate the accumulation of unfolded/misfolded proteins accumulation within the EnR. Citation Format: Katherine L. Cook, Pamela A.G. Clarke, Margaret Axelrod, Anni Wärri, Robert Clarke. Novel role of glucose-regulated protein 78 mediating lipid metabolism through controlling stearoyl-CoA desaturase 1. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2443. doi:10.1158/1538-7445.AM2014-2443