Fatty Acid Synthase Levels Research Articles

A comparison between high carbohydrate and high lipid diets reception on the growth, feed utilization and glucose homeostasis of genetically improved farmed tilapia Oreochromis niloticus

This study was performed to compare the effects of high carbohydrate and high lipid diets reception on the growth, feed utilization and glucose homeostasis of genetically improved farmed tilapia Oreochromis niloticus. Three isonitrogenous (ca 30.2% protein) diets were formulated with different levels of starch and lipid: the control (CON, 24.2% starch and 6.57% lipid), high carbohydrate diet (HCD, 33.8% starch and 6.91% lipid), and high lipid diet (HLD, 24.0% starch and 16.5% lipid). Tilapia juveniles (initial mean body weight: 32.2 ± 0.2 g/fish) were randomly divided into 12 rectangular tanks (250 L) with 20 fish per tank, and fed the diets to apparent satiation for 8 weeks. The results showed that mean body weight was lower in the HLD fish (183 g/fish) than in the CON (212 g/fish) and HCD fish (206 g/fish). Feeding ratio and feed efficiency ratio were not affected by different treatments. Both dietary starch and lipid provision in excess exhibited poor protein-sparing effect, as protein efficiency ratio and protein productive value were not affected while whole-body protein percentages were lower in the HCD and HLD fish than in the CON fish. High lipid diets reception exerted a greater impact on proximate composition of the whole fish and intraperitoneal fat deposition, while high carbohydrate diets reception exerted a greater impact on liver size through promoting glycogen deposition. Plasma glucose level sharply increased in the HLD fish (7.17 mmol/L) as compared with the CON fish (4.66 mmol/L). Evidences from the molecular level revealed that hyperglycemia of the HLD fish was probably resulted from hepatic glucose output (represented by mRNA levels of glucose transporter 2 and glucose-6-phosphatase catalytic subunit a2) through stimulating gluconeogenesis (the expression of phosphoenolpyruvate carboxykinase 2) rather than glycogenolysis. In addition, high lipid diets reception suppressed hepatic de novo lipogenesis (mRNA level of fatty acid synthase (fas)) along with muscular glucose transport (mRNA level of glucose transporter 4) and glycogenesis (the expression of glycogen synthase 1), which aggravated the hyperglycemia of the HLD fish. In contrast, high carbohydrate diets reception did not affect the expression of representative genes involved with glycolysis and gluconeogenesis, but sharply upregulated the mRNA abundances of lipogenic acetyl-CoA carboxylase α and fas in the liver of tilapia. Except lipid, glycogen concentration also increased in the liver of the HCD fish as compared with the CON fish. Thus, plasma glucose slightly increased in the HCD fish (5.58 mmol/L) as compared with the CON fish. The overall results of this study suggested that tilapia possessed a better capability to tolerate high carbohydrate diets (33.8%) than high lipid diets (16.5%) based on growth performance and the maintenance of glucose homeostasis. This conclusion might have limitations, because the energy density of diets HCD and HLD was different. Further studies are still warranted to compare the glucose homeostasis of tilapia in response to high carbohydrate and high lipid diets reception on an isoenergetic basis.

The role of altered fatty acid in pathological scars and their dermal fibroblasts

PurposeThe proposed pathological mechanism for scar formation is controversial, and increased attention has been paid to the fatty acids (FAs) in the formation of pathological scars. Notably, FAs are known to be important in inflammation and mechanotransduction, which is closely related to scar formation. Therefore, it is necessary to clarify the roles of FA in scar formation. MethodsHypertrophic scar and keloid formed for more than a year and without other treatment, as well as normal skin samples were obtained from patients who underwent plastic surgery. Finally, keloids (n = 10), hypertrophic scars (n = 10), and normal skin samples (n = 10) were collected under informed consent. Primary dermal fibroblasts were isolated and cultured. The amount and variety of FAs were detected by lipid chromatography-mass spectrometry. Immunohistochemistry, real-time PCR, and western blotting were used to verify the expression of sterol regulatory element-binding protein-1 (SREBP1) and fatty acid synthase (FASN) in the samples and their fibroblasts. Student's t-test, ANOVA, and orthogonal partial least square discriminant analysis were performed for statistical analysis (∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001). ResultsCompared with full-thickness normal skin, there were 27 differential FAs in keloids and 15 differential FAs in hypertrophic scars (∗p < 0.05 and variable influence on projection >1.0). The expression of SREBP1 and FASN was lower in pathological scars both at mRNA and protein levels (all ∗p < 0.05). However, the mRNA levels of SREBP1 (∗∗∗p = 0.0002) and FASN (∗∗∗p = 0.0021) in keloid-derived fibroblasts were higher than that in normal skin fibroblasts (NFBs), while the expression in hypertrophic scar-derived fibroblasts was lower than that in NFBs (both ∗p < 0.05). Whereas there was no significant difference in FASN protein expression between keloid-derived fibroblasts and NFBs (p > 0.05). ConclusionFAs involved in pathological scars are abnormally changed in scar formation. Thus, fatty acid-derived inflammation and de novo synthesis pathway of FA may play a key role in the formation of pathological scars.

Influence of Dietary Inositol Supplementation on Growth, Liver Histology, Lipid Metabolism, and Related Genes Expression on Juvenile Hybrid Grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatu) Fed High-Lipid Diets

An 8-week feeding trial was conducted to investigate the effects of dietary inositol on growth performance, lipid metabolism, and expression of lipid related genes of hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatu) (initial body weight 6.76 ± 0.34 g). Six isonitrogenous and isolipidic (16.35%) diets were formulated to contain graded levels of inositol (0.17 g/kg (J1), 0.62 g/kg (J2), 1.03 g/kg (J3), 1.78 g/kg (J4), 3.43 g/kg (J5), and 6.59 g/kg (J6)). The results indicated that (a) weight gain rate appeared gradually increasing trend and significant increase in four inositol treatments (J3, J4, J5, and J6) ( P &lt; 0.05 ). Protein efficiency ratio was slightly improved in the J4 group ( P &lt; 0.05 ), but there was no significant difference exhibiting in survival rate between the inositol-treated groups and the control group ( P &gt; 0.05 ). (b) In serum, dietary inositol significantly reduced the contents of triglyceride (TG), total cholesterol (TC), low-density lipoprotein, and clearly increased the content of high-density lipoprotein ( P &lt; 0.05 ). In the liver, dietary inositol significantly decreased contents of TG, TC, and very low-density lipoprotein ( P &lt; 0.05 ). The activities of lipoprotein lipase, hepatic lipase, and adipose triglyceride lipase were slightly improved in the inositol-treated groups ( P &lt; 0.05 ). (c) With increasing of inositol supplement, decreasing of lipid droplet could be observed in hepatocyte. (d) In the liver, dietary inositol significantly downregulated the mRNA levels of fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), 6-phosphogluconate dehydrogenase (6PGD), and sterol regulatory element-binding protein-1 (SREBP1) ( P &lt; 0.05 ), while it remarkably upregulated the mRNA levels of lipoprotein lipase (LPL), hormone-sensitive lipase (HSL), and carnitine palmitoyl transferase1 (CPT1) ( P &lt; 0.05 ). In summary, dietary inositol improved growth and reduced lipid composition in the liver of hybrid grouper through decreasing of fatty acid synthesis and increasing of lipid catabolism. Under the experimental conditions, broken-line regression analysis showed that 1.23~1.67 g/kg dietary inositol was recommended in juvenile grouper high-lipid diets.

Metabolomic Effects of the Dietary Inclusion of Hermetia illucens Larva Meal in Tilapia.

Black soldier fly (Hermetia illucens) larvae meal have been used as feed protein supplements in fish feed, but few researches have investigated the metabolomic effects of Hermetia illucens larvae meal supplements. Therefore, the metabolic effects on Nile tilapia were investigated by replacing 5%, 10%, and 20% of the dietary soybean meal in the basal diet with Hermetia illucens larvae meal, respectively. This study shows that 20% H. illucens larvae meal feed could promote tilapia average daily gain of upto 5.03 ± 0.18 g (mean ± SEM). It was found that the tricarboxylic acid cycle efficiency was improved by activating the enzymes of mitochondrial isocitrate dehydrogenase, NAD-malate dehydrogenase, succinate dehydrogenase, pyruvate dehydrogenase, and α-ketoglutarate dehydrogenase, which then increased the output of ATP and NADH. Furthermore, amino acid and protein biosynthesis was boosted by enhanced glutamine synthetase and glutamate synthase. In particular, GSH increased with increased H. illucens larvae meal. Unsaturated fatty acid biosynthesis was stimulated by higher levels of fatty acid synthase and acetyl CoA carboxylase. Additionally, there was no significant change in lipase levels. Thus, the higher acetyl Co-A content was primarily involved in fatty acid biosynthesis and energy metabolism. Flavor substances, such as nonanal and 2-methyl-3-furanthiol, also accumulated with the addition of H. illucens larvae meal, which increased the umami taste and meat flavor. Additionally, the flavor of tilapia was improved owing to a decrease in trimethylamine content, which causes an earthy and fishy taste. This study uncovers a previously unknown metabolic effect of dietary H. illucens larvae meal on Nile tilapia.

Alleviation of Hepatic Steatosis: Dithizone-Related Gut Microbiome Restoration During Paneth Cell Dysfunction.

Non-alcoholic fatty liver disease (NAFLD), the world’s most common chronic liver disease, is increasingly linked to gut dysbiosis. Paneth cells secrete antimicrobial peptides that regulate the gut microbiome, but their role in the pathogenesis of NAFLD remains unclear. Here, we determine the changes in NAFLD development and gut microbial composition and function via the injection of dithizone that can pharmacologically deplete the granules of Paneth cells. Eight-week-old C57BL/6J male mice (n = 31) were given a high-fat diet (HFD) or standard control diet for 12 weeks. Dithizone (10 mg/kg) was intravenously injected every 3 weeks during the period of diet feeding. Metagenomic DNA was extracted from fecal samples for PacBio Single-Molecule Real-Time sequencing to identify changes in microbial composition and predicted function. We observed dithizone-treated HFD mice, when compared to non-treated HFD mice, to have significant reductions in hepatic triglyceride content (28.98 vs. 53.52 mg/g, p = 0.0419); plasma insulin level (2.18 vs. 6.63 ng/ml, p = 0.0079); and relative mRNA levels of fatty acid synthase (0.52 vs. 1.57, p = 0.0428) and stearoyl-CoA desaturase-1 (0.43 vs. 1.20, p = 0.0121). Bacterial taxonomic profiling found dithizone-treated HFD mice, when compared to non-treated HFD mice, had a lower Firmicutes/Bacteroidetes ratio (2.53 vs. 5.26, p = 0.0541); a higher relative abundance of Bacteroides ASV21 and ASV42 (1.04 vs. 0.22%, p = 0.0277 and 0.96 vs. 0.09%, p = 0.0213); and a reduction in microbes belonging to Firmicutes (all p < 0.05). Bacteroides species correlated positively with predicted microbial functions such as L-methionine (r = 0.54, p = 0.0019) and tetrahydrofolate (r = 0.52, p = 0.0029) biosynthesis. Collectively, dithizone treatment was associated with alleviation in the severity of liver steatosis in HFD mice, possibly through gut microbiome modulation involving the increase in Bacteroides, suggesting microbiome-targeted therapies may have a role in the treatment of NAFLD.

Effects of in ovo feeding of t10,c12-conjugated linoleic acid on hepatic lipid metabolism and subcutaneous adipose tissue deposition in newly hatched broiler chicks

The purpose of this study was to investigate whether in ovo feeding of t10,c12-conjugated linoleic acid (CLA) could regulate hepatic lipid metabolism and decrease lipid accumulation in newly hatched chicks. Three hundred and sixty fertilely specific pathogen-free hatching eggs were selected and randomly divided into 6 groups. On embryonic day 11 of incubation (E11), 0, 1.5, 3.0, 4.5, 6.0, or 7.5 mg t10,c12-CLA were injected into the eggs. The results indicated that in ovo feeding of t10,c12-CLA significantly decreased the subcutaneous adipose tissue (SAT) mass and the relative SAT weight of newly hatched chicks in linear and quadratic manners (P < 0.05). In liver, the levels of triglycerides were reduced linearly and quadratically and total cholesterol were reduced quadratically as the dose of t10,c12-CLA increased (P < 0.05). Meanwhile, the hepatic carnitine palmitoyltransferase-1a (CPT1a) content and polyunsaturated fatty acid proportion were increased quadratically in t10,c12-CLA groups (P < 0.05), accompanied by the decrease of malondialdehyde level and the increase of glutathione peroxidase and total antioxidant capacity activities (P < 0.05). In addition, in ovo feeding of t10,c12-CLA decreased the mRNA expression levels of fatty acid synthase, acetyl-CoA carboxylase 1 in linear and quadratic manners (P < 0.05), and decreased the mRNA expression of adipose triacylglyceride lipase and stearoyl-CoA desaturase significantly in liver (P < 0.05), accompanied by upregulating the mRNA expression of CPT1a quadratically and AMP-activated protein kinase α linearly and quadratically (P < 0.05). In SAT, the mRNA expression of peroxisome proliferator-activated receptor γ (PPARγ) and sterol regulatory element-binding protein-1c were decreased linearly and quadratically (P < 0.05), and the expression of PPARα and CPT1a genes were increased linearly and quadratically as the dose of t10,c12-CLA increased (P < 0.05). In conclusion, our findings demonstrate that in ovo feeding of t10,c12-CLA alleviates lipid accumulation in newly hatched chicks by suppressing fatty acid synthesis and stimulating lipolysis in the liver and inhibiting adipocyte differentiation in subcutaneous adipose tissue.

Evaluation of the expression of fatty acid synthase and O-GlcNAc transferase in patients with liver cancer by exploration of transcriptome databases and experimental approaches.

Tumor occurrence and development are closely related to metabolism abnormalities. One of the metabolic networks that is dysregulated during carcinogenesis is the fatty acid synthesis pathway, which is mainly controlled by fatty acid synthase (FASN). We previously demonstrated in proliferating HepG2 liver cancer cells that FASN expression depends on the catalytic activity of O-GlcNAc transferase (OGT) and the activation of the mechanistic/mammalian target of rapamycin (mTOR) pathway. The aim of the present study was to go further in these investigations by analyzing datasets and tissues of patients with liver cancer. To that purpose, transcriptome databases were explored, and reverse transcription-quantitative PCR, western blotting and immunohistochemistry were used. Database analyses revealed that FASN and OGT gene expression was higher in certain cancer tissues, including liver hepatocellular carcinoma, compared with that in non-cancerous tissues. At the protein level, FASN expression was higher in the liver cancer-derived cell lines HepG2 and Hep3B compared with the immortalized human hepatocytes IHH cell line. However, neither the expression of OGT nor of its product O-GlcNAcylation showed any significant difference among the three hepatic cell lines. Subsequently, the expression of FASN and OGT at the protein and mRNA levels was evaluated in human liver cancer and non-tumoral tissues from the same patients with different liver lesions. The results from western blotting demonstrated a significant increase in OGT ands O-GlcNAcylation expression in liver cancer tissues independently of the type of lesion characterizing the non-tumoral counterpart. As previously reported for HepG2 proliferating cells, the protein level of FASN was positively correlated with the activation of mTOR and, although a rather upward trend, a high variability in its expression was monitored between patients. However, the results from immunohistochemistry showed no particular modification for OGT and O-GlcNAcylation expression and a significant increase in FASN expression in cancer tissues compared with that in adjacent non-tumoral tissues. Non-significant changes were observed for FASN and OGT mRNA levels between tumoral and non-tumoral samples, with a high variability between patients. Taken together, these results demonstrated that FASN expression was higher in hepatic cancer tissues in comparison with non-tumoral tissues. Furthermore, OGT expression and activity were shown to vary greatly between cell or cancer type, making any generalization difficult.

Effects of the Probiotic Lactiplantibacillus plantarum KU15120 Derived from Korean Homemade Diced-Radish Kimchi Against Oxidation and Adipogenesis.

Intestinal microflora can influence abnormal adipocyte growth. Therefore, this study was aimed to investigate the probiotic properties and antioxidant and antiobesity effects of isolated strains from homemade kimchi. Among the isolated strains, Lactiplantibacillus plantarum KU15120 showed high tolerance to artificial gastric juice and bile salt conditions, high adhesion to HT-29 cells, nonproduction of β-glucuronidase, nonhemolysis, and acceptable resistance to antibiotics. It showed high antioxidant activity, including DPPH and ABTS radical scavenging and antioxidant activity, as determined by the β-carotene bleaching assay. Oil red O staining and intracellular triglyceride levels revealed reduced lipid accumulation, which confirmed the anti-adipogenic activity of L. plantarum KU15120. In addition, the expression levels of fatty acid synthase, CCAAT/enhance-binding proteinα, and peroxisome proliferator-activated receptorγ, were significantly lower in the probiotic-treated group than in the control group. These results suggest that L. plantarum KU15120 has probiotic properties, antioxidant, and antiobesity effects and could be used as a therapeutic probiotics.

CircWHSC1 Promotes Breast Cancer Progression by Regulating the FASN/AMPK/mTOR Axis Through Sponging miR-195-5p.

Numerous studies reveal that circular RNAs (circRNAs) affect cancer progression. CircWHSC1 is a novel circRNA that accelerates ovarian cancer progression. Nevertheless, the function of circWHSC1 in regulating breast cancer (BC) is elusive. Here, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was carried out to detect the profiles of circWHSC1 and miR-195-5p in BC tissues and corresponding non-tumor tissues. Gain- and loss-of-function assays were implemented both in vivo and ex vivo to verify the significance of circWHSC1 in BC development. BC cell proliferation was estimated by the cell counting kit-8 (CCK-8) and BrdU assays. Transwell assay was implemented to test BC cell migration and invasion. The protein levels of FASN, AMPK and mTOR were determined by Western blot. Moreover, immunohistochemistry was performed to examine Ki67 and FASN expression. As shown by the result, circWHSC1 was up-regulated in BC tissues versus adjacent non-tumor tissues. circWHSC1 overexpression was correlated with higher tumor stages, lymphatic metastasis and worse survival of BC patients. Functionally, overexpressing circWHSC1 amplified proliferation, migration and invasion of BC cell lines and boosted xenograft tumor growth in nude mice. Bioinformatics uncovered that circWHSC1 functioned as a competitive endogenous RNA by sponging miR-195-5p, which was further corroborated by the dual-luciferase reporter assay and RNA immunoprecipitation. miR-195-5p delayed BC progression, which was dampened by circWHSC1 up-regulation. Fatty acid synthase (FASN) was affirmed as a direct target of miR-195-5p. miR-195-5p overexpression curbed FASN expression and activated its downstream AMPK pathway. Inhibition of FASN or activation of the AMPK pathway reversed circWHSC1-mediated oncogenic effects. Collectively, CircWHSC1 acted as an oncogene to expedite BC evolvement by modulating the miR-195-5p/FASN/AMPK/mTOR pathway.

Halogenated bisphenol a analogues induce PPARγ-independent toxicity within human hepatocellular carcinoma cells

Tetrabromobisphenol A (TBBPA) and tetrachlorobisphenol A (TCBPA) – both halogenated bisphenol (BPA) analogues – are suspected ligands of peroxisome proliferator-activated receptor gamma (PPARγ). While previous studies have shown that TBBPA and TCBPA activate PPARγ within cell-free assays, the downstream effects of TBBPA- and TCBPA-induced PPARγ activation on cellular transcription and physiology have not been thoroughly investigated. Therefore, the objective of this study was to determine whether exposure to TBBPA or TCBPA (either alone or in combination) alters levels of neutral lipids and fatty acid synthase (FASN) – an enzyme that catalyzes synthesis of long-chain saturated fatty acids – within intact cells in a PPARγ-dependent manner. For this study, we relied on human hepatocellular carcinoma (HepG2) cells as a model since these liver cells express basal levels of PPARγ and have been used to study lipoprotein metabolism and regulation of drug metabolizing enzymes. Although exposure to TBBPA and TCBPA alone did not affect cell viability nor neutral lipid and FASN levels in a concentration-dependent manner, exposure to binary mixtures of TBBPA and TCBPA resulted in a concentration-dependent decrease in cell viability in the absence of concentration-dependent effects on neutral lipid and FASN levels. Interestingly, exposure to TBBPA or TCBPA alone or as a mixture enhanced the effects of a reference PPARγ agonist (ciglitazone) and antagonist (GW 9662) on cell viability (but not neutral lipid levels), suggesting that these two halogenated BPA analogues may interact synergistically with ciglitazone and GW 9662 to induce cytotoxicity. However, overexpression of PPARγ did not mitigate nor enhance the effects of TBBPA – a potent PPARγ ligand predicted by ToxCast’s cell-free competitive binding assays – on cell viability, neutral lipid levels, nor the cellular transcriptome. Overall, our findings suggest that halogenated BPA analogues such as TCBPA and TBBPA induce toxicity within HepG2 cells in a PPARγ-independent manner.

MicroRNA-21 deficiency suppresses prostate cancer progression through downregulation of the IRS1-SREBP-1 signaling pathway.

Sterol regulatory element-binding protein 1 (SREBP-1), a master transcription factor in lipogenesis and lipid metabolism, is critical for disease progression and associated with poor outcomes in prostate cancer (PCa) patients. However, the mechanism of SREBP-1 regulation in PCa remains elusive. Here, we report that SREBP-1 is transcriptionally regulated by microRNA-21 (miR-21) in vitro in cultured cells and in vivo in mouse models. We observed aberrant upregulation of SREBP-1, fatty acid synthase (FASN) and acetyl-CoA carboxylase (ACC) in Pten/Trp53 double-null mouse embryonic fibroblasts (MEFs) and Pten/Trp53 double-null mutant mice. Strikingly, miR-21 loss significantly reduced cell proliferation and suppressed the prostate tumorigenesis of Pten/Trp53 mutant mice. Mechanistically, miR-21 inactivation decreased the levels of SREBP-1, FASN, and ACC in human PCa cells through downregulation of insulin receptor substrate 1 (IRS1)-mediated transcription and induction of cellular senescence. Conversely, miR-21 overexpression increased cell proliferation and migration; as well as the levels of IRS1, SREBP-1, FASN, and ACC in human PCa cells. Our findings reveal that miR-21 promotes PCa progression by activating the IRS1/SREBP-1 axis, and targeting miR-21/SREBP-1 signaling pathway can be a novel strategy for controlling PCa malignancy.

Fatty acid synthase as a potential new therapeutic target for cervical cancer

Fatty acid synthase (FASN) is the rate-limiting enzyme for the de novo synthesis of fatty acids in the cytoplasm of tumour cells. Many tumour cells express high levels of FASN, and its expression is associated with a poorer prognosis. Cervical cancer is a major public health problem, representing the fourth most common cancer affecting women worldwide. To date, only a few in silico studies have correlated FASN expression with cervical cancer. This study aimed to investigate in vitro FASN expression in premalignant lesions and cervical cancer samples and the effects of a FASN inhibitor on cervical cancer cells. FASN expression was observed in all cervical cancer samples with increased expression at more advanced cervical cancer stages. The FASN inhibitor (orlistat) reduced the in vitro cell viability of cervical cancer cells (C-33A, ME-180, HeLa and SiHa) in a time-dependent manner and triggered apoptosis. FASN inhibitor also led to cell cycle arrest and autophagy. FASN may be a potential therapeutic target for cervical cancer, and medicinal chemists, pharmaceutical researchers and formulators should consider this finding in the development of new treatment approaches for this cancer type.

Anastrozole Regulates Fatty Acid Synthase in Breast Cancer.

Our previous matched case-control study of postmenopausal women with resected early-stage breast cancer revealed that only anastrozole, but not exemestane or letrozole, showed a significant association between the 6-month estrogen concentrations and risk of breast cancer. Anastrozole, but not exemestane or letrozole, is a ligand for estrogen receptor α. The mechanisms of endocrine resistance are heterogenous and with the new mechanism of anastrozole, we have found that treatment of anastrozole maintains fatty acid synthase (FASN) protein level by limiting the ubiquitin-mediated FASN degradation, leading to increased breast cancer cell growth. Mechanistically, anastrozole decreases the guided entry of tail-anchored proteins factor 4 (GET4) expression, resulting in decreased BCL2-associated athanogene cochaperone 6 (BAG6) complex activity, which in turn, prevents RNF126-mediated degradation of FASN. Increased FASN protein level can induce a negative feedback loop mediated by the MAPK pathway. High levels of FASN are associated with poor outcome only in patients with anastrozole-treated breast cancer, but not in patients treated with exemestane or letrozole. Repressing FASN causes regression of breast cancer cell growth. The anastrozole-FASN signaling pathway is eminently targetable in endocrine-resistant breast cancer.

A Two-Stage Adaptive Laboratory Evolution Strategy to Enhance Docosahexaenoic Acid Synthesis in Oleaginous Thraustochytrid.

Thraustochytrid is a promising algal oil resource with the potential to meet the demand for docosahexaenoic acid (DHA). However, oils with high DHA content produced by genetic modified thraustochytrids are not accepted by the food and pharmaceutical industries in many countries. Therefore, in order to obtain non-transgenic strains with high DHA content, a two-stage adaptive laboratory evolution (ALE) strategy was applied to the thraustochytrid Aurantiochytrium sp. Heavy-ion irradiation technique was first used before the ALE to increase the genetic diversity of strains, and then two-step ALE: low temperature based ALE and ACCase inhibitor quizalofop-p-ethyl based ALE were employed in enhancing the DHA production. Using this strategy, the end-point strain E-81 with a DHA content 51% higher than that of the parental strain was obtained. The performance of E-81 strain was further analyzed by component analysis and quantitative real-time PCR. The results showed that the enhanced in lipid content was due to the up-regulated expression of key enzymes in lipid accumulation, while the increase in DHA content was due to the increased transcriptional levels of polyunsaturated fatty acid synthase. This study demonstrated a non-genetic approach to enhance lipid and DHA content in non-model industrial oleaginous strains.

USP14 Regulates Cancer Cell Growth in a Fatty Acid Synthase-Independent Manner.

Fatty acid synthase (FASN) plays an important role in cancer development, providing excess lipid sources for cancer growth by participating in de novo lipogenesis. Although several inhibitors of FASN have been developed, there are many limitations to using FASN inhibitors alone as cancer therapeutics. We therefore attempted to effectively inhibit cancer cell growth by using a FASN inhibitor in combination with an inhibitor of a deubiquitinating enzyme USP14, which is known to maintain FASN protein levels in hepatocytes. However, when FASN and USP14 were inhibited together, there were no synergistic effects on cancer cell death compared to inhibition of FASN alone. Surprisingly, USP14 rather reduced the protein levels and activity of FASN in cancer cells, although it slightly inhibited the ubiquitination of FASN. Indeed, treatment of an USP14 inhibitor IU1 did not significantly affect FASN levels in cancer cells. Furthermore, from an analysis of metabolites involved in lipid metabolism, metabolite changes in IU1-treated cells were significantly different from those in cells treated with a FASN inhibitor, Fasnall. These results suggest that FASN may not be a direct substrate of USP14 in the cancer cells. Consequently, we demonstrate that USP14 regulates proliferation of the cancer cells in a fatty acid synthase-independent manner, and targeting USP14 in combination with FASN may not be a viable method for effective cancer treatment.

The Inhibitory Effects of 6-Thioguanine and 6-Mercaptopurine on the USP2a Target Fatty Acid Synthase in Human Submaxillary Carcinoma Cells

Overexpression of the deubiquitinase USP2a leads to stabilization of fatty acid synthase (FAS), the levels of which are often elevated in aggressive human cancers. Consequently, there is an urgent need for inhibitors to suppress the deubiquitination activity of USP2a so as to upregulate FAS protein degradation. We first analyzed the relationship between the expression level of USP2a and survival using The Cancer Genome Atlas Head-Neck Squamous Cell Carcinoma (HNSC) data collection. Our results suggested survival rates were lower among HNSC patients expressing higher levels of USP2a. We then investigated two thiopurine drugs, 6-thioguanine (6-TG) and 6-mercaptopurine (6-MP), to determine whether they could potentially serve as inhibitors of USP2a. Western blot analysis showed that levels of two USP2a target proteins, FAS and Mdm2, were dose-dependently decreased in A253 submaxillary carcinoma cells treated with 6-TG or 6‐MP. Responding to the degradation of Mdm2, levels of p53 were increased. We found that 6-TG and 6-MP also suppressed levels of both USP2a mRNA and protein, suggesting these two thiopurines do not act solely through direct inhibition of USP2a. The effects of 6-TG and 6-MP were not cell type-specific, as they elicited similar decreases in FAS protein in leukemia, prostate and cervical cancer cell lines. 6-TG and 6-MP had effects on several cell cycle proteins, including another USP2a target protein, cyclin D1. The populations of cells in subG1 and S phase were increased by 6-TG and 6-MP, which was accompanied by reductions in G1 phase cells. In untreated cells, USP2a transfection increased FAS and cyclin D1 levels compared to an enzyme-dead USP2a C276A mutant, which lacked deubiquitinating activity. However, USP2a transfection failed to reverse the suppressive effects of 6‐TG and 6-MP on FAS levels. In summary, these findings suggest 6-TG and 6-MP reduce the stability of some USP2a targets, including FAS and Mdm2, by inhibiting USP2a-catalyzed deubiquitination in some cancer cells. Our work also provides repurposing evidence supporting 6‐TG and 6-MP as target therapeutic drugs, such as USP2a/FAS in this study.

Effect of Betaine Diet on Growth Performance, Carcass Quality and Fat Deposition in Finishing Ningxiang Pigs.

Simple SummaryExcessive fat deposit is one of the major problems in finishing Ningxiang pigs, and adversely affects the breeding. The study aimed to investigate the effects of diet with betaine supplementation (basal diet + 0.2% betaine) on the growth performance, slaughter performance, meat quality and the genes expression related to fat deposition in finishing Ningxiang pigs. The results indicated that diet with betaine supplementation decreased back fat thickness and fat percentage, and increased the lean meat percentage as well. In addition, it reduced the fat deposition by regulating the genes expression. These findings provided a reference for breeding Ningxiang pigs. The present study was conducted to investigate the effects of diet with betaine supplementation on the growth performance, carcass quality and fat deposition in finishing Ningxiang pigs. A total of 24 Ningxiang pigs (43.6 ± 5.34 kg of average body weight) was randomly divided into two groups, with 6 replicates per treatment and 2 pigs per replicate. The treatments included a control group (basal diet) and a test group (basal diet + 0.2% betaine). The whole trial lasted 81 days. At the end of the experiment, one pig (close to the average body weight of all experimental pigs) per replicate was slaughtered to determine the carcass traits, meat quality and the mRNA expression levels of genes relate to fat deposition (one pig per replicate was randomly selected and fasted for 12 h, n = 6). Results indicated that growth performance was not changed with betaine supplementation. However, dietary with betaine supplementation decreased back fat thickness and fat percentage, and increased the lean meat percentage as well (p < 0.05). In addition, diet with betaine supplementation reduced drip loss, water loss, cooking loss, shear force and b × 24 h value of meat (p < 0.05). There was no difference in total moisture, ether extract and crude protein of longissimus thoracis between the control and test group. Dietary with betaine supplementation decreased ether extract and total cholesterol (p < 0.05) in liver. Dietary with betaine supplementation upregulated the mRNA expression levels of adipose triglyceride lipase (ATGL) and sirtuin 1 (Sirt1), while downregulated the mRNA expression levels of fatty acid synthase (FAS) and acetyl CoA carboxylase (ACC) in subcutaneous fat of back (p < 0.05). Besides, dietary with betaine supplementation upregulated the fatty acid binding protein 4 (FABP4) mRNA expression of longissimus thoracis in finishing Ningxiang pigs (p < 0.05). These results showed that diet supplemented with betaine could improve the slaughtering performance and meat quality, and regulate the genes expression to affect the fat deposition in finishing Ningxiang pigs.

In Vitro Investigations of miR-33a Expression in Estrogen Receptor-Targeting Therapies in Breast Cancer Cells.

Simple SummaryAltered metabolic pathways determine the aggressivity of breast cancer cells. To highlight the potential markers gains importance to understand early molecular signatures of disease. microRNAs are the small non-coding RNAs found in different biological samples. Due to the dysregulation of metabolic pathways, the expression and secretion of microRNAs are modulated.(1) Background: Increased fatty acid synthesis leads to the aggressive phenotype of breast cancer and renders efficiency of therapeutics. Regulatory microRNAs (miRNAs) on lipid biosynthesis pathways as miR-33a have potential to clarify the exact mechanism. (2) Methods: We determined miR-33a expression levels following exposure of MCF-7 and MDA-MB-231 breast cancer cells to estrogen receptor (ER) activator (estradiol-17β, E2) or anti-estrogens (ICI 182,780, Fulvestrant, FUL) at non-cytotoxic concentrations. We related miR-33a expression levels in the cells to cellular lipid biosynthesis-related pathways through immunoblotting. (3) Results: miR-33a mimic treatment led to significantly downregulation of fatty acid synthase (FASN) in MCF-7 cells but not in MDA-MB-231 cells in the presence of estradiol-17β (E2) or Fulvestrant (FUL). In contrast to the miR-33a inhibitor effect, miR-33a mimic co-transfection with E2 or FUL led to diminished AMP-activated protein kinase α (AMPKα) activity in MCF-7 cells. E2 increases FASN levels in MDA-MB-231 cells regardless of miR-33a cellular levels. miR-33a inhibitor co-treatment suppressed E2-mediated AMPKα activity in MDA-MB-231 cells. (4) Conclusions: The cellular expression levels of miR-33a are critical to understanding differential responses which include cellular energy sensors such as AMPKα activation status in breast cancer cells.

Dihydroartemisinin ameliorates retinal vascular dysfunction in diabetes mellitus via the FASN/Kmal-mTOR/SREBP1 feedback loop

Microvascular dysfunction is the primary aetiology of visual impairment caused by diabetic retinopathy (DR). Dihydroartemisinin (DHA), the active metabolite of the antimalarials artemisinins, exhibits antiangiogenic properties in numerous diseases. Here, we investigated the function and mechanisms of DHA as a vasculoprotective agent in DR. DHA exerted its protective effect on vascular injuries in diabetic mice and inhibited cell proliferation and tube formation in human retinal microvascular endothelial cells by decreasing the level of fatty acid synthase (FASN), enhancing the malonylation of mechanistic target of rapamycin (mTOR) at lysine 1218 (K1218) and attenuating the activation of mTOR complex 1 (mTORC1). Impressively, a chemosynthetic small interfering RNA against FASN and mutagenesis of K1218 of mTOR showed therapeutic potential in suppressing cell proliferation and tube formation induced by high glucose. Notably, suppression of mTORC1 kinase activity further inhibited FASN by reducing p70S6K phosphorylation to subsequently reduce the expression of sterol regulatory element binding protein 1, which interacted directly with the FASN promoter at nucleotide positions −64 and −55. In conclusion, our study elucidated the promising effects of FASN and malonylation on vascular injuries of DR and indicated the great potential of DHA as a therapeutic approach.

FASN inhibition sensitizes metastatic OSCC cells to cisplatin and paclitaxel by downregulating cyclin B1.

To investigate the potential effect of fatty acid synthase (FASN) inhibitor orlistat to enhance the effectiveness of chemotherapy drugs widely used to treat oral squamous cell carcinomas (OSCC), such as 5-fluorouracil, cisplatin, and paclitaxel. The OSCC SCC-9 LN-1metastatic cell line, which expresses high levels of FASN, was used for drug combination experiments. Cell viability was analyzed by crystal violet staining and automatic cell counting. Apoptosis and cell cycle were analyzed by flow cytometry with Annexin-V/7-AAD and propidium iodide staining, respectively. Cyclin B1, Cdc25C, Cdk1, FASN, and ERBB2levels were assessed by Western blotting. Finally, cell scratch and transwell assays were performed to assess cell migration and invasion. Inhibition of FASN with orlistat sensitized SCC-9 LN-1 cells to the cytotoxic effects of paclitaxel and cisplatin, but not 5-fluorouracil, which was accompanied by a significant reduction in cyclin B1. The suppression of proliferation, migration, and invasion of SCC-9 LN-1 cells induced by orlistat plus cisplatin or paclitaxel was not superior to the effects of chemotherapy drugs alone. Our results suggest that orlistat enhances the chemosensitivity of SCC-9 LN-1 cells to cisplatin and paclitaxel by downregulating cyclin B1.