Overexpression Of Fatty Acid Synthase Research Articles

Comparison of fatty acid synthase and cyclooxygenase-2 immunoexpression in embryonal, benign, and malignant odontogenic tissues

The aim of this study was to analyze the immunohistochemical expression of fatty acid synthase (FASN) and cyclooxygenase-2 (COX-2) in tooth germ (TG), ameloblastoma (AM), ameloblastic carcinoma (AC), ameloblastic fibroma (AF), and ameloblastic fibrosarcoma (AFS). Immunohistochemistry for FASN and COX-2 was performed in 10 TG, 44 AM, 10 AC, 9 AF, and 5 AFS specimens. The results were analyzed by using the immunoreactive score (IRS) and Kruskal-Wallis test followed by Dunn's post-test. Most TG specimens were strongly positive for FASN, whereas COX-2 was weak or negative. All AM and AC specimens expressed both proteins. In AF specimens, FASN and COX-2 were variably expressed in the epithelium and negative in the mesenchyme. In AFS specimens, FASN was strongly positive in the malignant mesenchyme and variable in the epithelium; COX-2 was focal or weak in both components. FASN expression showed significant differences in the following comparisons: TG vs AC, AM vs AC, and AF vs AFS. Differences in COX-2 were significant when comparing TG specimens with AM, AC, and AF specimens. The results suggest that FASN and COX-2 overexpression may have a role in the pathogenesis of AM and AC, whereas in AFS, FASN seems to be mainly involved. Further studies are necessary to clarify these mechanisms and their clinical implications.

Inhibition of de novo lipogenesis targets androgen receptor signaling in castration-resistant prostate cancer

A hallmark of prostate cancer progression is dysregulation of lipid metabolism via overexpression of fatty acid synthase (FASN), a key enzyme in de novo fatty acid synthesis. Metastatic castration-resistant prostate cancer (mCRPC) develops resistance to inhibitors of androgen receptor (AR) signaling through a variety of mechanisms, including the emergence of the constitutively active AR variant V7 (AR-V7). Here, we developed an FASN inhibitor (IPI-9119) and demonstrated that selective FASN inhibition antagonizes CRPC growth through metabolic reprogramming and results in reduced protein expression and transcriptional activity of both full-length AR (AR-FL) and AR-V7. Activation of the reticulum endoplasmic stress response resulting in reduced protein synthesis was involved in IPI-9119-mediated inhibition of the AR pathway. In vivo, IPI-9119 reduced growth of AR-V7-driven CRPC xenografts and human mCRPC-derived organoids and enhanced the efficacy of enzalutamide in CRPC cells. In human mCRPC, both FASN and AR-FL were detected in 87% of metastases. AR-V7 was found in 39% of bone metastases and consistently coexpressed with FASN. In patients treated with enzalutamide and/or abiraterone FASN/AR-V7 double-positive metastases were found in 77% of cases. These findings provide a compelling rationale for the use of FASN inhibitors in mCRPCs, including those overexpressing AR-V7.

Activation of sterol regulatory element-binding protein 1 (SREBP1)-mediated lipogenesis by the Epstein-Barr virus-encoded latent membrane protein 1 (LMP1) promotes cell proliferation and progression of nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is closely associated with Epstein–Barr virus (EBV) infection. The EBV‐encoded latent membrane protein 1 (LMP1), which is commonly expressed in NPC, engages multiple signaling pathways that promote cell growth, transformation, and metabolic reprogramming. Here, we report a novel function of LMP1 in promoting de novo lipogenesis. LMP1 increases the expression, maturation and activation of sterol regulatory element‐binding protein 1 (SREBP1), a master regulator of lipogenesis, and its downstream target fatty acid synthase (FASN). LMP1 also induces de novo lipid synthesis and lipid droplet formation. In contrast, small interfering RNA (siRNA) knockdown of LMP1 in EBV‐infected epithelial cells diminished SREBP1 activation and lipid biosynthesis. Furthermore, inhibition of the mammalian target of rapamycin (mTOR) pathway, through the use of either mTOR inhibitors or siRNAs, significantly reduced LMP1‐mediated SREBP1 activity and lipogenesis, indicating that LMP1 activation of the mTOR pathway is required for SREBP1‐mediated lipogenesis. In primary NPC tumors, FASN overexpression is common, with high levels correlating significantly with LMP1 expression. Moreover, elevated FASN expression was associated with aggressive disease and poor survival in NPC patients. Luteolin and fatostatin, two inhibitors of lipogenesis, suppressed lipogenesis and proliferation of nasopharyngeal epithelial cells, effects that were more profound in cells expressing LMP1. Luteolin and fatostatin also dramatically inhibited NPC tumor growth in vitro and in vivo. Our findings demonstrate that LMP1 activation of SREBP1‐mediated lipogenesis promotes tumor cell growth and is involved in EBV‐driven NPC pathogenesis. Our results also reveal the therapeutic potential of utilizing lipogenesis inhibitors in the treatment of locally advanced or metastatic NPC. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Nicotine induces oral dysplastic keratinocyte migration via fatty acid synthase-dependent epidermal growth factor receptor activation

Despite advances in diagnostic and therapeutic management, oral squamous cell carcinoma (OSCC) patient survival rates have remained relatively unchanged. Thus, identifying early triggers of malignant progression is critical to prevent OSCC development. Traditionally, OSCC initiation is elicited by the frequent and direct exposure to multiple tobacco-derived carcinogens, and not by the nicotine contained in tobacco products. However, other nicotine-containing products, especially the increasingly popular electronic cigarettes (e-cigs), have unknown effects on the progression of undiagnosed tobacco-induced oral premalignant lesions, specifically in regard to the effects of nicotine. Overexpression of fatty acid synthase (FASN), a key hepatic de novo lipogenic enzyme, is linked to poor OSCC patient survival. Nicotine upregulates hepatic FASN, but whether this response occurs in oral dysplastic keratinocytes is unknown. We hypothesized that in oral dysplastic keratinocytes, nicotine triggers a migratory phenotype through FASN-dependent epidermal growth factor receptor (EGFR) activation, a common pro-oncogenic event supporting oral carcinogenesis. We report that in oral dysplastic cells, nicotine markedly upregulates FASN leading to FASN-dependent EGFR activation and increased cell migration. These results raise potential concerns about e-cig safety, especially when used by former tobacco smokers with occult oral premalignant lesions where nicotine could trigger oncogenic signals commonly associated with malignant progression.

Inhibitory Effects of Cichorium Intybus Root Extract on the Proliferation and Lipogenesis of the SKBR3 Cells

Background: Fatty acid synthase (FASN) is a key enzyme in de novo lipogenesis pathway. FASN overexpression is a common feature of many human cancers like breast cancer. Furthermore, FASN expression in HER2 - positive cell lines like SKBR3 is more than other cell lines, such as MCF - 7, which are not HER2 - positive. Cichorium intybus is a medicinal herb and methanolic extract of this plant significantly suppressed cell viability and growth in some cancer cells. Objectives: In this study, we aimed at investigating the effect of methanolic extract of Cichorium intybus on the FASN expression and, therefore, lipogenesis pathway in human breast cancer SKBR3 cell line. Methods: We assessed the cytotoxicity effect of Chicorium intybus on the cell viability of SKBR3 cells, using MTT assay. In addition, apoptosis rate was assessed by annexinV/PI flow cytometry. Finally, Real time q - PCR was used for the analysis of FASN gene expression. Results: The results showed that the methanolic extract of Cichorium intybus caused a dose - dependent decrease in the cell viability of SKBR3 cells. Additionally, the treatment of confluent SKBR3 cells with extract led to reduced FASN expression at mRNA level. Conclusions: These results suggest that Chicorium intybus not only inhibits cell viability in a dose - dependent manner, but also presumably inhibits lipogenesis by markedly decreased FASN expression as a key lipogenic enzyme.

Probiotics Strains Modulate Gut Microbiota and Lipid Metabolism in Mule Ducks.

Background:Livestock production should respond to societal, environmental and economic changes. Since 2006 and the ban on antibiotics as growth factors in European Union, the use of probiotics has become widespread and has demonstrated the effect of intestinal microbiota on the performance of farm animals.Objective:The aim of this study was to investigate the effect of supplementation with Lactobacillus salivarius (as a probiotics strain or combined with other strains) on zootechnical performance, metabolic and immune gene expression and intestinal microbiota diversity in mule ducks using high-throughput sequencing and real-time PCR.Method:The mule ducks were reared for 79 days and overfed for 12 days with or without probiotics. Samples were collected at 14 (starting period) and 91 days (end of overfeeding period), 3 hours post feeding.Results:Irrespective of digestive content, age, level of feed intake or supplementation with probiotics, Firmicutes, Proteobacteria and Bacteroidetes were the dominant phyla in the bacterial community in mule ducks. At 14 days, both the ileal and cecal samples were dominated by Firmicutes (in particular the Clostridiales order). Overfeeding induced a shift between Clostridiales and Lactobacillales in the ileal samples whereas in the cecal samples, the relative abundance of Firmicutes decreased. Overfeeding also induced hepatic over-expression of Fatty Acid Synthase (FAS) and of the lipid transporter gene Fatty Acid Binding Protein 4 (FABP4). This increase in lipid metabolism genes is associated with a decrease in inflammatory response.Conclusion:Finally, probiotic supplementation had only a slight impact on gene expression and microbiota diversity, both at 14 days and after overfeeding.

The effect of FASN inhibition on the growth and metabolism of a cisplatin-resistant ovarian carcinoma model.

Overexpression of fatty acid synthase (FASN), a key regulator of the de novo synthesis of fatty acids, has been demonstrated in a variety of cancers and is associated with poor prognosis and increased multidrug resistance. Inhibition of FASN with the anti‐obesity drug orlistat has been shown to have significant anti‐tumourigenic effects in many cancers, notably breast and prostate. In our study, we investigated whether FASN inhibition using orlistat is an effective adjunctive treatment for ovarian cancers that have become platinum resistant using a cisplatin‐resistant ovarian tumour xenograft model in mice. Mice were treated with orlistat or cisplatin or a combination and metabolite analysis and histopathology were performed on the tumours ex vivo. Orlistat decreased tumour fatty acid metabolism by inhibiting FASN, cisplatin reduced fatty acid β‐oxidation, and combination treatment delayed tumour growth and induced apoptotic and necrotic cell death in cisplatin‐resistant ovarian cancer cells over and above that with either treatment alone. Combination treatment also decreased glutamine metabolism, nucleotide and glutathione biosynthesis and fatty acid β‐oxidation. Our data suggest that orlistat chemosensitised platinum‐resistant ovarian cancer to treatment with platinum and resulted in enhanced efficacy.

Upregulation of pyruvate kinase M2 expression by fatty acid synthase contributes to gemcitabine resistance in pancreatic cancer.

Pancreatic cancer has one of the highest mortality rates of all cancer types. Fatty acid synthase (FASN) is a multifunctional protein homodimer that can convert acetyl coenzyme A (CoA) and malonyl-CoA into palmitate, thus regulating lipogenesis. FASN overexpression has also been shown to cause resistance to gemcitabine, a chemotherapy treatment for pancreatic cancer; however, the mechanism by which this happens is unclear. Analysis of gene expression of FASN and pyruvate kinase M2 (PKM2) in pancreatic cancer was performed using Oncomine microarray gene expression datasets, which demonstrated that FASN and PKM2 were upregulated in pancreatic cancer compared with normal tissue. Specifically, it was demonstrated that FASN enabled the upregulation of PKM2 expression at the mRNA and protein levels, increasing the glucose consumption rate in pancreatic cancer cells. The present study also revealed that decreased levels of FASN reduced resistance to gemcitabine treatment, which was induced by PKM2 overexpression in pancreatic ductal adenocarcinoma cells. Therefore, FASN may represent a novel therapeutic target in pancreatic cancer.

Overexpressed Fatty Acid Synthase in Gastrointestinal Stromal Tumors: Targeting a Progression-Associated Metabolic Driver Enhances the Antitumor Effect of Imatinib.

Purpose: In gastrointestinal stromal tumors (GIST), lipid-metabolizing enzymes remain underexplored, including fatty acid synthase (FASN).Experimental Design: Forty GISTs were quantitated for FASN mRNA abundance. FASN immunoexpression was informative in 350 GISTs, including 213 with known KIT/PDGFRA/BRAF genotypes. In imatinib-resistant FASN-overexpressing GIST cells, the roles of overexpressed FASN and FASN-targeting C75 in tumor phenotypes, apoptosis and autophagy, KIT transcription, PI3K/AKT/mTOR activation, and imatinib resistance were analyzed by RNAi or myristoylated-AKT transfection. The therapeutic relevance of dual blockade of FASN and KIT was evaluated in vivoResults:FASN mRNA abundance significantly increased from very low/low-risk to high-risk levels of NCCN guidelines (P < 0.0001). FASN overexpression was associated with a nongastric location (P = 0.05), unfavorable genotype (P = 0.005), and increased risk level (P < 0.001) and independently predicted shorter disease-free survival (P < 0.001). In vitro, FASN knockdown inhibited cell growth and migration, inactivated the PI3K/AKT/mTOR pathway, and resensitized resistant GIST cells to imatinib. C75 transcriptionally repressed the KIT promoter, downregulated KIT expression and phosphorylation, induced LC3-II and myristoylated AKT-suppressible activity of caspases 3 and 7, attenuated the PI3K/AKT/mTOR/RPS6/4E-BP1 pathway activation, and exhibited dose-dependent therapeutic additivism with imatinib. Compared with both monotherapies, the C75/imatinib combination more effectively suppressed the growth of xenografts, exhibiting decreased KIT phosphorylation, Ki-67, and phosphorylated PI3K/AKT/mTOR levels and increased TUNEL labeling.Conclusions: We have characterized the prognostic, biological, and therapeutic implications of overexpressed FASN in GISTs. C75 represses KIT transactivation, abrogates PI3K/AKT/mTOR activation, and provides a rationale for dual blockade of KIT and FASN in treating imatinib-resistant GISTs. Clin Cancer Res; 23(16); 4908-18. ©2017 AACR.

Abstract 457: Satisfying the fatty acid demand of prostate cancer: Outlier overexpression of genes involved in de novo synthesis vs fatty acid uptake define two different and potentially synergistic prostate cancer phenotypes

Abstract Malignant transformation increases cellular demand for fatty acids (FA). Many cancers, including prostate cancer (PCa), show increased expression of fatty acid synthase (FASN), the enzyme that catalyzes the de novo synthesis of the FA palmitate. De novo FA synthesis is energetically expensive; in most normal cells FASN expression is low and de novo synthesis suppressed in favor of utilization of exogenous FA. In contrast, in cancer cells, de novo FA synthesis is an important source of precursors needed to support tumor growth. Much of the research effort on FA in cancer has focused on FASN and the other genes involved in de novo FA synthesis. However a number of observations suggest that alternate mechanisms for FA acquisition are also important, most notably studies showing that cancer cells can be rescued from the pro-apoptotic effect of FASN inhibition by exogenous palmitate. Using a biopsy-based approach designed to identify high risk prostate cancer phenotypes that are common in African American (AA) men, we identified a PCa subtype with outlier (&amp;gt; 10 fold) mRNA overexpression of fatty acid binding protein 5 (FABP5). FABP5 facilitates the utilization of palmitate and other FAs from outside the cell, and a FABP5 overexpression phenotype may confer a selective advantage when dietary FAs are abundant or when FASN is targeted as a therapy. The FABP5 outlier overexpression phenotype was observed in 7% Gleason sum (GS) 7-10 PCas. We also observed a second molecular subtype with outlier FASN overexpression in 9% of GS 7-10 PCas. With few exceptions these two PCa subtypes showed an “either-or” pattern with top quartile overexpression of FABP5 or FASN but not both (Spearman r = 0.385; P &amp;lt; 0.0001). Interestingly, in low grade (GS 6) PCas, median FABP5 mRNA overexpression is higher in AA than in European American (EA) men (P &amp;lt; 0.01) with GS6 PCas from AA men showing median FABP5 expression levels as high as that observed in GS 7-10 PCas. IHC confirmed variable expression of both FABP5 and FASN, including “patchwork” PCas with high Gleason pattern (GP) areas overexpressing FABP5 next to low GP areas overexpressing FASN. The net result may be a selective advantage for the high grade cancer if FABP5 allows it to exploit the FA being synthesized by the adjacent low grade focus. In a subset of PCas, FABP5 IHC showed robust nuclear staining consistent with its proposed role in regulating fatty acid mediated gene expression; the ratio of FABP5 nuclear/cytoplasmic staining was higher in PCa from AA than from EA patients (P &amp;lt; 0.05). Identification of a PCa subtype with high levels of FABP5 overexpression suggests a previously unrecognized mechanism by which some PCas can increase FA supply without de novo synthesis. Such a PCa subtype might be particularly sensitive to dietary interventions and relatively insensitive to FASN inhibitors. Citation Format: Sandra M. Gaston, James Kearns, George W. Adams, Soroush Rais-Bahrami, Jeffrey W. Nix, Peter N. Kolettis, James E. Bryant, Mark S. DeGuenther, Denise Oelschlager, Dennis Otali, William E. Grizzle. Satisfying the fatty acid demand of prostate cancer: Outlier overexpression of genes involved in de novo synthesis vs fatty acid uptake define two different and potentially synergistic prostate cancer phenotypes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 457. doi:10.1158/1538-7445.AM2017-457

Satisfying the fatty acid demand of prostate cancer: De novo synthesis versus uptake as alternative and potentially cooperative prostate cancer phenotypes.

107 Background: Malignant transformation increases cellular demand for fatty acids (FA). Many cancers show increased expression of fatty acid synthase (FASN); FASN catalyzes the de novo synthesis of the FA palmitate. While research has focused on FASN and de novo tumor FA synthesis, observations suggest that alternate mechanisms for FA acquisition are also important, including studies showing that cancer cells can be rescued from FASN inhibition by exogenous palmitate. Using a biopsy-based approach, we identified a PrCa subtype with outlier (&gt;10 fold) overexpression of fatty acid binding protein 5 (FABP5). FABP5 facilitates the utilization of palmitate and other FAs from outside the cell; a FABP5 overexpression phenotype may confer a selective advantage when dietary FAs are abundant or when FASN is targeted as a therapy. Methods: 244 prostate biopsy patients were prospectively enrolled. Tissue prints were collected from each core for RNA and DNA preparation. mRNA was analyzed using Affymetrix arrays and TaqMan qrtPCR assays. Immunohistochemistry (IHC) was performed using archival radical prostatectomy (RP) specimens. Results: mRNA analyses revealed a PrCa subtype with &gt;10 x overexpression of FABP; this phenotype was observed in 7% of 268 cores with Gleason sum (GS) 7-10 PrCa. We also observed a second subtype with &gt;10 x overexpression of FASN in 9% of GS 7-10 cores. With few exceptions these two PrCa subtypes showed an “either-or” pattern with top-quartile overexpression of FABP5 or FASN but not both (Spearman r = - 0.385; P &lt; 0.0001). IHC confirmed variable expression, including “patchwork” PrCas with high Gleason pattern (GP) areas overexpressing FABP5 next to low GP areas overexpressing FASN. The net result may be a selective advantage for the high grade cancer if FABP5 allows it to exploit the FA being synthesized by the adjacent low grade focus Conclusions: Identification of a PrCa subtype with high levels of FABP5 overexpression suggests a previously unrecognized mechanism by which some PrCas can increase FA supply without de novo synthesis; such a PrCa subtype might be particularly sensitive to dietary interventions and relatively insensitive to FASN inhibitors.

Fatty acid synthase – Modern tumor cell biology insights into a classical oncology target

Decades of preclinical and natural history studies have highlighted the potential of fatty acid synthase (FASN) as a bona fide drug target for oncology. This review will highlight the foundational concepts upon which this perspective is built. Published studies have shown that high levels of FASN in patient tumor tissues are present at later stages of disease and this overexpression predicts poor prognosis. Preclinical studies have shown that experimental overexpression of FASN in previously normal cells leads to changes that are critical for establishing a tumor phenotype. Once the tumor phenotype is established, FASN elicits several changes to the tumor cell and becomes intertwined with its survival. The product of FASN, palmitate, changes the biophysical nature of the tumor cell membrane; membrane microdomains enable the efficient assembly of signaling complexes required for continued tumor cell proliferation and survival. Membranes densely packed with phospholipids containing saturated fatty acids become resistant to the action of other chemotherapeutic agents. Inhibiting FASN leads to tumor cell death while sparing normal cells, which do not have the dependence of this enzyme for normal functions, and restores membrane architecture to more normal properties thereby resensitizing tumors to killing by chemotherapies. One compound has recently reached clinical studies in solid tumor patients and highlights the need for continued evaluation of the role of FASN in tumor cell biology. Significant advances have been made and much remains to be done to optimally apply this class of pharmacological agents for the treatment of specific cancers.

Clinicopathological Significance and Correlation of Fatty Acid Synthase (FASN) and HER2 Expression in Infiltrating Duct Carcinoma of the Breast

Objective: This study aimed to correlate the immunohistochemical expression of fatty acid synthase (FASN) and HER-2 with the clinicopathological variables in breast infiltrating duct carcinoma (IDC) to identify the impact of marker expression on tumor behavior and mammary carcinogenesis and to detect the correlations between the two markers. Methods: Immunohistochemical expressions of FASN and HER-2 were evaluated in 77 breast case including 10 normal breast, 12 ductal carcinoma in situ (DCIS) and 55 IDC and correlated with clinicopathological variables. The obtained data were statistically analyzed. Results: FASN was overexpressed in 91.7% and 70.9% of DCIS and IDC, respectively, with a significant difference from the normal (P = 0.000). In IDC, the expression of FASN was significantly more expressed in low-grade IDC (P = 0.031). FASN was significantly upregulated in larger tumors and lymph node metastasis (P = 0.017 and P = 0.046, respectively). The expression of FASN had a significant negative correlation with progesterone receptor (PR) (P = 0.05). HER-2 was overexpressed in 50% and 25.45% of DCIS and IDC, respectively, with a significant difference from the normal (P = 0.026). HER-2 was only expressed in high-grade DCIS (P = 0.007). In IDC, the expression of HER-2 was significantly up-regulated in larger tumors and lymph node metastasis (P = 0.033 and P = 0.015, respectively). The expression of HER-2 had a significant negative correlation with estrogen receptor (ER) and PR (P = 0.001 and P = 0.023, respectively). Correlation between the expression of FASN and HER-2 in IDC, revealed a significant positive correlation (Spearman correlation [r] = 0.374, P = 0.005). Conclusions: We concluded that overexpression of FASN and HER-2 may facilitate the early diagnosis of IDC. In IDC, their over expression might warn of a more aggressive course. Our correlation found that FAS expression is closely associated with over expression of HER-2 in IDC.

Genes involved in the establishment of hepatic steatosis in Muscovy, Pekin and mule ducks

Our main objectives were to determine the genes involved in the establishment of hepatic steatosis in three genotypes of palmipeds. To respond to this question, we have compared Muscovy ducks, Pekin ducks and their crossbreed the mule duck fed ad libitum or overfed. We have shown a hepatic overexpression of fatty acid synthase (FAS) and di-acyl glycerol acyl transferase 2 (DGAT2) in overfed individuals, where DGAT2 seemed to be more regulated. This increase in lipogenesis genes is associated with a decrease of lipoprotein formation in Muscovy and mule ducks, especially apolipoprotein B (ApoB) and Microsomal Triglyceride Transfer Protein (MTTP), leading to lipid accumulation in liver. In Pekin ducks, MTTP expression is upregulated suggesting a better hepatic lipids exportation. Regarding lipids re-uptake, fatty acid-binding protein 4 and very-low-density-lipoprotein receptor are overexpressed in liver of mule ducks at the end of the overfeeding period. This phenomenon puts light on a mechanism unknown until today. In fact, mule can incorporate more lipids in liver than the two other genotypes leading to an intensified hepatic steatosis. To conclude, our results confirmed the genotype variability to overfeeding. Furthermore, similar observations are already described in non-alcoholic fatty liver disease in human, and ask if ducks could be an animal model to study hepatic triglyceride accumulation.

FASN regulates cellular response to genotoxic treatments by increasing PARP-1 expression and DNA repair activity via NF-κB and SP1

Fatty acid synthase (FASN), the sole cytosolic mammalian enzyme for de novo lipid synthesis, is crucial for cancer cell survival and associates with poor prognosis. FASN overexpression has been found to cause resistance to genotoxic insults. Here we tested the hypothesis that FASN regulates DNA repair to facilitate survival against genotoxic insults and found that FASN suppresses NF-κB but increases specificity protein 1 (SP1) expression. NF-κB and SP1 bind to a composite element in the poly(ADP-ribose) polymerase 1 (PARP-1) promoter in a mutually exclusive manner and regulate PARP-1 expression. Up-regulation of PARP-1 by FASN in turn increases Ku protein recruitment and DNA repair. Furthermore, lipid deprivation suppresses SP1 expression, which is able to be rescued by palmitate supplementation. However, lipid deprivation or palmitate supplementation has no effect on NF-κB expression. Thus, FASN may regulate NF-κB and SP1 expression using different mechanisms. Altogether, we conclude that FASN regulates cellular response against genotoxic insults by up-regulating PARP-1 and DNA repair via NF-κB and SP1.

Leucine deprivation inhibits proliferation and induces apoptosis of human breast cancer cells via fatty acid synthase.

Substantial studies on fatty acid synthase (FASN) have focused on its role in regulating lipid metabolism and researchers have a great interest in treating cancer with dietary manipulation of amino acids. In the current study, we found that leucine deprivation caused the FASN-dependent anticancer effect. Here we showed that leucine deprivation inhibited cell proliferation and induced apoptosis of MDA-MB-231 and MCF-7 breast cancer cells. In an in vivo tumor xenograft model, the leucine-free diet suppressed the growth of human breast cancer tumors and triggered widespread apoptosis of the cancer cells. Further study indicated that leucine deprivation decreased expression of lipogenic gene FASN in vitro and in vivo. Over-expression of FASN or supplementation of palmitic acid (the product of FASN action) blocked the effects of leucine deprivation on cell proliferation and apoptosis in vitro and in vivo. Moreover, leucine deprivation suppressed the FASN expression via regulating general control non-derepressible (GCN)2 and sterol regulatory element-binding protein 1C (SREBP1C). Taken together, our study represents proof of principle that anticancer effects can be obtained with strategies to deprive tumors of leucine via suppressing FASN expression, which provides important insights in prevention of breast cancer via metabolic intervention.

N-phenylmaleimides affect adipogenesis and present antitumor activity through reduction of FASN expression

In light of the evidence that in contrast to most healthy tissues, several neoplasms overexpress fatty acid synthase (FASN) upon their dependence on increased lipogenesis; targeting of this protein is being considered as a valuable strategy in anticancer drug development. This can be particularly relevant for aggressive tumors such as melanoma in which FASN overexpression has been associated with increased depth of invasion and worse prognosis. We have previously shown that a sub-class of cyclic imides, the N-phenylmaleimides, presented antitumor activity against L1210 leukemia and B16F10 melanoma with evidences of interference in the energetic metabolism. Here, we aimed to investigate if some selected N-phenylmaleimides (M1 and M5) interfere with fatty acids metabolism and its relation with cancer. For that, a model of pre-adipocytes differentiation (3T3-L1 cells) and also human melanoma cells (SK-Mel-147) were used. As results, when 3T3-L1 cells were exposed to non-cytotoxic concentrations of M1 and M5 in the presence of an adipogenic cocktail, intracellular lipid content decreased by 26–36%, marking the inhibition of adipocyte differentiation. High selectivity indexes were obtained for both compounds for tumoral cells. Cell cycle phases analysis revealed a remarkable proportion of cells with DNA fragmentation after their exposure to M1 and M5. This was correlated to both apoptosis and necrosis, showed by Annexin-V/PI assay. Furthermore, M1 and M5 reduced FASN expression by 19–39%, respectively. In conclusion, M1 and M5 presented antiadipogenic and antitumoral activities. The antitumoral activity that was associated to apoptosis and necrosis is a possible consequence of the FASN reduction, which in turn, might result in a fuel decrease to cell proliferation. As it happens with antiangiogenic activity, reduction of fatty acid synthesis might be a potential target for cancer treatment in a strategy of hunger-strike, which valorizes these N-phenylmaleimides as candidates for drug development.

Abstract 20: Outlier overexpression of genes involved in fatty acid metabolism and processing define two aggressive prostate cancer phenotypes

Abstract Major shifts in fatty acid metabolism are part of the malignant phenotype of many types of cancer, including prostate cancer. We have used a biopsy based approach to characterize high grade prostate cancers in both African American and European American patients. This approach allows us to analyze prostate cancers from patients whose disease is too advanced for radical prostatectomy and who are thus not represented in the study specimens available from conventional biorepositories. mRNA gene expression profiling of high grade prostate cancers from biopsies revealed cancer subtypes with very high (&amp;gt;10 fold) levels of overexpression of fatty acid binding protein 5 (FABP5) and fatty acid synthase (FASN). Interestingly, these prostate cancer subtypes showed an either-or phenotype, with “super-overexpression” of either FABP5 or FASN but not both. These findings suggest two “outlier” prostate cancer subtypes with striking differences in the pathways that drive a shift in tumor fatty acid metabolism; one is a fatty acid synthase (FASN) dominant phenotype and the other a previously unrecognized fatty acid binding protein (FABP5) dominant phenotype. In contrast, prostate cancers with lower levels of FABP5 and/or FASN overexpression (2-4 fold) often co-overexpressed both of these genes. Immunohistochemical analyses confirmed prostate cancer FABP5 and FASN overexpression; both showed strong cytoplasmic staining. FABP5 also showed robust nuclear staining consistent with its proposed role in regulating fatty acid mediated gene expression. At both the mRNA and protein levels, the high grade prostate cancers with the highest levels of FABP5 over-expression were more common in African Americans, while the highest levels FASN overexpression were more common in prostate cancers from European Americans. These findings may provide the basis for more effective dietary interventions and targeted therapies for African American and European American patients with these two different subtypes of high grade prostate cancer. Citation Format: Sandra M. Gaston, Kerry Dehimer, James Kearns, Kyle-Ravi Chinsky, Dennis Otali, Denise Oelschlager, Soroush Rais-Bahrami, Jeffrey W. Nix, Peter Kolettis, George W. Adams, William E. Grizzle. Outlier overexpression of genes involved in fatty acid metabolism and processing define two aggressive prostate cancer phenotypes. [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 20.

Abstract 1021: Lipidomic analysis: a powerful tool for evaluating lipid metabolism in cultured cancer cells

Abstract Lipids have numerous functions in biological processes, structural as well as regulatory. Cancer cells show differences from healthy normal cells in their metabolism, including lipid metabolism, which contribute to their survival and growth. Overexpression of fatty acid synthase (FASN) is commonly observed in cancer cells and there is also evidence of other lipid pathways being changed in tumor cells. The general aim of this project is to establish a lipidomic based UPLC-QToF method for evaluation of lipid composition in cultured cells of normal and cancerous origin using electrospray quadrupole traveling wave ion mobility Q-ToF mass spectrometry. Cell lines were selected based on their lipid metabolism, including three breast cancer cell lines: SK-Br-3 (overexpresses FASN), T47D (TP53-mutated), MCF7 (estrogen receptor-positive); and one pancreatic cancer cell line, ASPC-1(overexpresses 5-and 12-lipoxygenases). Furthermore, we analyzed the immortalized breast epithelial stem cell line D492 along with its subline, D492M, that has undergone epithelial to mesenchymal transition (EMT). Principal component analysis (PCA) revealed distinct differences in lipid composition between all the cell lines tested, each cell line showed a clear cluster of lipid components and patterns that were reproducible between experiments. The Sk-Br-3 was most clearly separated from the other two breast cancer cell lines. Further analysis revealed significant differences in levels of phosphocholins (PC) that are elevated in Sk-Br-3compared to other cell lines. Further investigations of the data have led to identification of certain PC that are different between cell lines. Significant differences were detected in the lipid composition of D492 and D492M. In conclusion, different levels of lipid-synthesizing enzymes are reflected in distinct lipid profiles in breast cancer cells. The observed differences in lipid profiles of the breast epithelial cell line and its mesenchymal-like subline may provide an insight into membrane changes associated with EMT and help evaluate lipidomes of tumor samples from patients in terms of invasive potential. Citation Format: Finnur F. Eiríksson, Manuela Magnusdottir, Skarphedinn Halldorsson, Margret Thorsteinsdottir, Helga M. Ögmundsdottir. Lipidomic analysis: a powerful tool for evaluating lipid metabolism in cultured cancer cells. [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 1021.

Hypertriglyceridemia: An Open Door for Cancer Treatment?

Does lipid management have a significant role in cancer treatment? Could hypertriglyceridemia be an accelerating factor in certain tumors? These questions have grown from the long-standing recognition of the relationship of lipids to certain cancers. Cancers express high levels of lipid synthase, the enzyme responsible for the production of fatty acids. Lymphoma and other cancers have been found to have the ability to generate the lipids via de novo lipogenesis at a rate faster than other lipogenetic tissues [1]. Continuous de novo lipogenesis provides cancer cells with membrane building blocks, signaling lipid molecules, posttranslational modifications of proteins as well as energy supply to support rapid cell proliferation [2]. Protection of cancer cells by apoptosis by overexpression of fatty acid synthase (FASN) also helps the progression of the cancer [2]. Recent studies have documented the changes in lipid levels in the etiology and most importantly prognosis of cancer [3, 4]. There are many studies that have shown that the degree of lipid abnormality was directly related to the underlying tumor burden in addition to the abnormality in triglyceride clearance [5]. In one study, 25 patients with acute leukemia and nonHodgkin’s lymphoma (NHL) were studied; all patients demonstrated an abnormality in at least one plasma lipid fraction that consisted of extremely low levels of high density lipoprotein (HDL), elevated triglycerides (TG) and elevated very low density lipoprotein (VLDL). The levels were found to be normalized after recovery [5]. Another study was performed to investigate serum lipid alterations in patients with acute lymphoblastic leukemia (ALL) at diagnosis and during remission of the disease. Plasma lipids and lipoproteins were measured at diagnosis, prior to the administration of induction treatment, and every 2 months for the first 12 months of the maintenance phase of chemotherapy in 64 patients with ALL. Nearly all patients demonstrated serum lipid alterations which included elevated TG, LDL and cholesterol and values were returned back to normal during remission [6]. This points out the direct link between cancer progression and lipid levels. Metastasis is another interesting area in which the lipid level can correlate with disease burden. In one study, 205 Iranian patients from Semnan Oncology Clinic were studied and there was a significant association between higher levels of serum LDL and metastasis [7]. Aggressiveness of the tumor including metastasis can be highlighted by the levels of lipids. This brings up to the point of our case. We present a patient with stage IV diffuse large B-cell NHL with diffuse involvement of the bone and liver whose course was complicated with an incidental finding of hypertriglyceridemia. A 67-year-old Caucasian male with a past medical history of chronic obstructive pulmonary disease, diabetes mellitus, hypertension, coronary artery disease, and pulmonary embolism was admitted to the hospital for severe lower back pain and significant weight loss for 1 month. He denied any familial or personal history of hypertriglyceridemia. Physical examination was remarkable for pale conjunctivae, positive straight leg test on the left lower extremity, and a limited range of motion in his right upper extremity. There was no point tenderness noted in his back but there was mild tenderness to palpation of the right chest wall. CT abdomen imaging revealed several masses in the liver which involved the lateral segment of the left lobe, the medial segment, and an illdefined mass in the right lobe posteriorly. Biopsy of the liver demonstrated evidence for diffuse large B-cell NHL and bone marrow involvement was also seen in bone marrow biopsy. Lipid profile drawn 2 years ago were found to be TG 195 mg/ dL, cholesterol 146 mg/dL, LDL 74 mg/dL, VLDL 39 mg/dL and HDL 33 mg/dL. The lipid panel had changed dramatically during this admission demonstrating TG 1,154 mg/dL, cholesterol 204 mg/dL, and HDL 4 mg/dL, and LDL and VLDL were unable to be calculated. This unusual level of TG highlighted the aggressiveness of the tumor and more importantly the prognosis of the cancer. The patient was treated with gemfibrozil and insulin. TG levels were markedly improved from 1,154 to 690 mg/dL. The patient deteriorated before initiation of chemotherapy and expired. The issue of interest in this case is not the specific attributes of the cancer discussed but of the rise and fall of TG associated with it. The possible implications of this event may correlate with the aggressiveness of the tumor or the type of cancer and presents an intriguing possibility of manipulating this process as a means of treatment. The current standards for Manuscript accepted for publication March 24, 2016