ACC Phosphorylation Research Articles

Abstract 1857: Proscillaridin A induces apoptosis and suppresses non-small cell lung cancer tumor growth via calcium-induced DR4 up-regulation

Abstract Non-small cell lung cancer (NSCLC) is the predominant histological type of lung cancer and is characterized by the highest mortality and incidence rates among these types of malignancies. Cardiac glycosides, a class of natural products, have been identified as a potential type of chemotherapeutic agent. This study aims to investigate the anti-cancer effects and the mechanisms of action of Proscillaridin A (P.A) in NSCLC cells. In vitro sodium-potassium pump (Na+/K+ ATPase) enzyme assays indicated that P.A is a direct Na+/K+ ATPase inhibitor. P.A showed potent cytotoxic effects in NSCLC cells at nanomolar levels. Treatment mechanism studies indicated that P.A elevated Ca2+ levels, activated the AMPK pathway and down-regulated phosphorylation of ACC and mTOR. Subsequently, P.A increased death receptor 4 (DR4) expression and down-regulated NF-κB. Interestingly, P.A selectively suppressed EGFR activation in EGFR mutant cells but not in EGFR wild-type cells. In vivo, P.A significantly suppressed tumor growth in nude mice compared to vehicle-treated mice. Compared with the Afatinib treatment group, P.A displayed less pharmaceutical toxicity, as the body weight of mice treated with P.A did not decrease as much as those treated with Afatinib. Consistent changes in protein levels were obtained from Western blotting analysis of tumors and cell lines. Immunohistochemistry analysis of the tumors from P.A-treated mice showed a significant suppression of EGFR phosphorylation (Tyr 1173) and reduction of the cell proliferation marker Ki67. Taken together, our results suggest that P.A is a promising anti-cancer therapeutic candidate for NSCLC. Acknowledgements This work was supported by the Macau Science Technology Development Fund (project code: 021/2013/A1, 005/2014/AMJ & 010/2016/A1). Note: This abstract was not presented at the meeting. Citation Format: Run-Ze Li, Xing Xing Fan, Xiao- Jun Yao, Elaine L. Leung, Liang Liu. Proscillaridin A induces apoptosis and suppresses non-small cell lung cancer tumor growth via calcium-induced DR4 up-regulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1857.

165-OR: The Mechanisms by Which Adiponectin Reverses Insulin Resistance in High-Fat Diet Fed Mice

Adiponectin has emerged as an antidiabetic adipokine, and a potential therapy to treat type 2 diabetes. However, the mechanism by which adiponectin improves insulin sensitivity remains unclear. To address this question, we examined the effects of a 2-week continuous infusion of globular adiponectin (gAcrp30) or saline (CON) on glucose and lipid metabolism in a high fat diet fed (HFD) mouse model. Whole-body and tissue-specific insulin action was assessed by a hyperinsulinemic-euglycemic clamp (HEC). gAcrp30-treated mice displayed reduced fasting plasma glucose and insulin concentrations (both P<0.05 vs. CON) and increased glucose infusion rate (14 vs. 22 mg/(kg-min), P<0.001) during the HEC reflecting increased whole-body insulin-sensitivity. Increased insulin sensitivity could be attributed to reduced endogenous glucose production (16.7 vs.14.2 mg/(kg-min), P<0.05), increased glucose uptake in muscle (191 vs. 285 nmol/(kg-min), p=0.006) and adipose tissues (BAT: 112 vs. 217, WAT: 11 vs. 22 nmol/(kg-min), both P<0.05) during the HEC. These improvements in liver and muscle insulin sensitivity were associated with ∼50% reductions in liver and muscle triglyceride (TAG) and ∼40% diacylglycerol (DAG) (both P<0.01 vs. CON) content but no changes in hepatic ceramide content. Reduced tissue TAG/DAG content occurred independent of changes in WAT lipolysis, hepatic AMPK activation, ACC phosphorylation or mitochondrial oxidation. Reduced tissue DAG content was associated with decreased PKCε activation in liver and PKCθ activation in muscle and increased insulin signaling in liver, muscle and white adipose tissue. Conclusion: Taken together these data support the hypothesis that adiponectin improves insulin sensitivity in liver and muscle of HFD fed mice by reducing ectopic lipid (DAG) content in these tissues leading to decreased nPKC activity and increased insulin signaling, and contrary to prior studies, is independent of changes in hepatic ceramide content. Disclosure X. Li: None. D. Zhang: None. R.J. Perry: Research Support; Self; AstraZeneca. D.F. Vatner: None. L. Goedeke: None. Y. Zhang: None. G.I. Shulman: Advisory Panel; Self; AstraZeneca, Janssen Research & Development, Merck & Co., Inc. Advisory Panel; Spouse/Partner; Merck & Co., Inc. Board Member; Self; Novo Nordisk A/S. Consultant; Self; Aegerion Pharmaceuticals, IMetabolic BioPharma Corporation, Longitude Capital, Nimbus Discovery, Inc., Staten Biotechnology B.V. Funding American Heart Association (19PRE34380268); National Institutes of Health (R01DK116774)

Pancreastatin inhibitor activates AMPK pathway via GRP78 and ameliorates dexamethasone induced fatty liver disease in C57BL/6 mice

AimsTo investigate the role of pancreastatin inhibitor (PSTi8) in lipid homeostasis and insulin sensitivity in dexamethasone induced fatty liver disease associated type 2 diabetes. Main methodsGlucose releases assay, lipid O staining and ATP/AMP ratio were performed in HepG2 cells. Twenty four mice were randomly divided into 4 groups: Control group (saline), DEX (1 mg/kg, im) for 17 days, DEX+PSTi8 (acute 5 mg/kg and chronic 2 mg/kg, ip) for 10 days. The glucose, insulin and pyruvate tolerance tests (GTT, ITT and PTT), biochemical parameters and Oxymax-CLAMS were performed. Further to elucidate the action mechanisms of PSTi8, we performed genes expression and western blotting of biological samples. Key findingsWe found that PSTi8 suppresses hepatic glucose release, lipid deposition, oxidative stress induced by DEX, stimulates the cellular energy level in hepatocytes and enhances GRP78 activity. It reduces lipogensis and enhances fatty acid oxidation to improve insulin sensitivity and glucose tolerance in DEX induced diabetic mice. The above cellular effects are the result of activated AMPK signalling pathway in liver, which increases Srebp1c and ACC phosphorylation. The increased ACC phosphorylation suppresses protein kinase C activity and enhances insulin sensitivity. The increased expression of UCP3 in liver elicits fatty acid oxidation and energy expenditure, which suppress oxidative stress. SignificanceThus the activation of AMPK signalling through GRP78, improves lipid homeostasis, enhances insulin sensitivity via inhibition of PKC activity. PSTi8 suppresses inflammation associated with incomplete fatty acid oxidation. Hence, PSTi8 may be a potential therapeutic agent to treat glucocorticoid-induced fatty liver associated type 2 diabetes.

Blunted Cardiac AMPK Response is Associated with Susceptibility to Ischemia/Reperfusion in Male Offspring of Gestational Diabetic Rats.

Gestational diabetes mellitus (GDM) is closely associated with early perinatal complications and long-term health problems, such as cardiovascular disease, in offspring. AMP-activated protein kinase (AMPK) is cardioprotective, particularly in the treatment of ischemia/reperfusion (I/R). However, whether GDM programs offspring susceptibility to cardiac I/R and the involvement of AMPK remain unclear. Streptozotocin was administered to rats during mid pregnancy; the postpartum maternal metabolome was assessed by chromatography-mass spectrometry (GC-MS). Male offspring were subjected to body composition scanning followed by ex vivo global I/R. Cardiac signaling was determined by Western blotting. The body weights (BWs) of the GDM male offspring were significantly heavier than those of the control group from the age of 8 weeks; the heart weights (HWs) and HW/BW were also increased in the GDM group compared to the control group. The ex vivo post-I/R cardiac contractile function recovery was significantly compromised in the GDM male offspring. The phosphorylation of AMPK and ACC was elevated by ex vivo I/R in both groups, but to a significantly lesser extent in the GDM group. GDM male offspring rats have higher risks of overgrowth and intolerance to cardiac I/R, which may be due to a compromised AMPK signaling pathway.

Exercise-induced AMPK activation and IL-6 muscle production are disturbed in adiponectin knockout mice

BackgroundAdiponectin exhibits anti-inflammatory actions and is mainly expressed in adipose tissue. However, recent studies have shown that adiponectin can also be secreted by skeletal muscle fibers with autocrine and paracrine effects. ObjectivesTo analyze the role of adiponectin in the metabolic and inflammatory response of skeletal muscle after acute exhaustive aerobic exercise. MethodsC57BL/6 (WT) and adiponectin knockout (AdKO) mice underwent four days of treadmill running adaptation and at the fifth day, they performed an incremental maximum test to determine the maximum speed (Vmax). Acute exercise consisted of one hour at 60% Vmax. Mice were euthanatized 2 and 24 h after acute exercise session. ResultsSerum and gastrocnemius adiponectin increased after 2-hours of acute exercise. NEFA concentrations were lower in non-exercise AdKO, and decreased 2-hours after exercise only in WT. No differences were found in muscle triacylglycerol content; however, glycogen content was higher in AdKO in non-exercise (p-value = 0.005). WT showed an increase in AMP-activated protein kinase (AMPK) phosphorylation 2-hours after exercise and its level went back to normal after 24-hours. Otherwise, exercise was not able to modify AMPK in the same way as in AdKO. WT showed an increase in the phosphorylation of ACC (Ser79) 2-hours after exercise and return to normal after 24-hours of exercise (p-value < 0.05), kinects that was not observed in AdKO mice. IL-10 and IL-6 concentration was completely different among genotypes. In WT, these cytokines were increased at 2 (p-value < 0.01) and 24 h (p-value < 0.001) after exercise when compared with AdKO. NF-κBp65 protein and gene expression were not different between genotypes. ConclusionAdiponectin influences muscle metabolism, mainly by the decrease in exercise-induced AMPK phosphorylation, inflammatory profile and IL-6 in the muscle.

Inhibition of Adipogenesis by Diphlorethohydroxycarmalol (DPHC) through AMPK Activation in Adipocytes.

The purpose of this study was to investigate the antiobesity effect and the mechanism of action of diphlorethohydroxycarmalol (DPHC) isolated from Ishige okamurae in 3T3-L1 cells. The antiobesity effects were examined by evaluating intracellular fat accumulation in Oil Red O-stained adipocytes. Based on the results, DPHC dose-dependently inhibited the lipid accumulation in 3T3-L1 adipocytes. DPHC significantly inhibited adipocyte-specific proteins such as SREBP-1c, PPARγ, C/EBP α, and adiponectin, as well as adipogenic enzymes, including perilipin, FAS, FABP4, and leptin in adipocytes. These results indicated that DPHC primarily acts by regulating adipogenic-specific proteins through inhibiting fat accumulation and fatty acid synthesis in adipocytes. DPHC treatment significantly increased both AMPK and ACC phosphorylation in adipocytes. These results indicate that DPHC inhibits the fat accumulation by activating AMPK and ACC in 3T3-L1 cells. Taken together, these results suggest that DPHC can be used as a potential therapeutic agent against obesity.

Anti-diabetic activity of canophyllol from Cratoxylum cochinchinense (Lour.) Blume in type 2 diabetic mice by activation of AMP-activated kinase and regulation of PPARγ.

In the present study, the potential anti-diabetic activity of canophyllol (CNPL) and its mechanisms were investigated in vitro and in vivo. CNPL is a predominant friedelane-type triterpene extracted from young leaves of Cratoxylum cochinchinense ("Huang Niu Tea"). In vitro, CNPL increased GLUT4 translation in a L6-myotube model to 2.60-fold, and glucose uptake to 1.71-fold levels relative to untreated L6 myotubes. Moreover, compound C, an inhibitor of AMP-activated protein kinase (AMPK), completely suppressed the CNPL-induced GLUT4 translocation. In vivo, serum insulin levels, hyperglycemia, as well as other blood indexes of the KK-Ay diabetic mice were improved by a four-week oral administration of CNPL. Examination of its possible anti-diabetic mechanism showed that CNPL promoted the expression of p-AMPKα and GLUT4 in L6 myotubes. In KK-Ay mice treated with CNPL, GLUT4 expression was increased in skeletal muscle and white adipose tissue, and the levels of p-AMPKα were increased in the liver, skeletal muscle and white adipose tissue. Moreover, CNPL stimulated the expression of PPARγ to decrease and inhibited the activity of ACC by stimulating its phosphorylation in both liver and white adipose tissue, thereby indicating that CNPL also improved lipid metabolism disorders. Altogether, these results show that CNPL may improve glucose tolerance, reduce hyperglycemia, normalize insulin secretion, and ameliorate lipid metabolism disorders. The diverse anti-diabetic effects of CNPL may be attributed to the regulation of GLUT4, PPARγ, AMPK phosphorylation and ACC phosphorylation.

Effects of intravenous AICAR (5-aminoimidazole-4-carboximide riboside) administration on insulin signaling and resistance in premature baboons, Papio sp.

Premature baboons exhibit peripheral insulin resistance and impaired insulin signaling. 5’ AMP-activated protein kinase (AMPK) activation improves insulin sensitivity by enhancing glucose uptake (via increased glucose transporter type 4 [GLUT4] translocation and activation of the extracellular signal-regulated kinase [ERK]/ atypical protein kinase C [aPKC] pathway), and increasing fatty acid oxidation (via inhibition of acetyl-CoA carboxylase 1 [ACC]), while downregulating gluconeogenesis (via induction of small heterodimer partner [SHP] and subsequent downregulation of the gluconeogenic enzymes: phosphoenolpyruvate carboxykinase [PEPCK], glucose 6-phosphatase [G6PASE], fructose- 1,6-bisphosphatase 1 [FBP1], and forkhead box protein 1 [FOXO1]). The purpose of this study was to investigate whether pharmacologic activation of AMPK with AICAR (5-aminoimidazole-4-carboximide riboside) administration improves peripheral insulin sensitivity in preterm baboons. 11 baboons were delivered prematurely at 125±2 days (67%) gestation. 5 animals were randomized to receive 5 days of continuous AICAR infusion at a dose of 0.5 mg·g-1·day-1. 6 animals were in the placebo group. Euglycemic hyperinsulinemic clamps were performed at 5±2 and 14±2 days of life. Key molecules potentially altered by AICAR (AMPK, GLUT4, ACC, PEPCK, G6PASE, FBP1, and FOXO1), and the insulin signaling molecules: insulin receptor (INSR), insulin receptor substrate 1 (IRS-1), protein kinase B (AKT), and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) were measured using RT-PCR and western blotting. AICAR infusion did not improve whole body insulin-stimulated glucose disposal in preterm baboons (12.8±2.4 vs 12.4±2.0 mg/(kg·min), p = 0.8, placebo vs AICAR). One animal developed complications during treatment. In skeletal muscle, AICAR infusion did not increase phosphorylation of ACC, AKT, or AMPK whereas it increased mRNA expression of ACACA (ACC), AKT, and PPARGC1A (PGC1α). In the liver, INSR, IRS1, G6PC3, AKT, PCK1, FOXO1, and FBP1 were unchanged, whereas PPARGC1A mRNA expression increased after AICAR infusion. This study provides evidence that AICAR does not improve insulin sensitivity in premature euglycemic baboons, and may have adverse effects.

Inhibition of Acetyl-CoA Carboxylase by Phosphorylation or the Inhibitor ND-654 Suppresses Lipogenesis and Hepatocellular Carcinoma

The incidence of hepatocellular carcinoma (HCC) is rapidly increasing due to the prevalence of obesity and non-alcoholic fatty liver disease, but the molecular triggers that initiate disease development are not fully understood. We demonstrate that mice with targeted loss-of-function point mutations within the AMP-activated protein kinase (AMPK) phosphorylation sites on acetyl-CoA carboxylase 1 (ACC1 Ser79Ala) and ACC2 (ACC2 Ser212Ala) have increased liver de novo lipogenesis (DNL) and liver lesions. The same mutation in ACC1 also increases DNL and proliferation in human liver cancer cells. Consistent with these findings, a novel, liver-specific ACC inhibitor (ND-654) that mimics the effects of ACC phosphorylation inhibits hepatic DNL and the development of HCC, improving survival of tumor-bearing rats when used alone and in combination with the multi-kinase inhibitor sorafenib. These studies highlight the importance of DNL and dysregulation of AMPK-mediated ACC phosphorylation in accelerating HCC and the potential of ACC inhibitors for treatment.

Antidiabetic Activity of a Flavonoid-Rich Extract From Sophora davidii (Franch.) Skeels in KK-Ay Mice via Activation of AMP-Activated Protein Kinase.

The present study was undertaken to investigate the hypoglycemic activity and potential mechanisms of action of a flavonoid-rich extract from Sophora davidii (Franch.) Skeels (SD-FRE) through in vitro and in vivo studies. Four main flavonoids of SD-FRE namely apigenin, maackiain, leachianone A and leachianone B were purified and identified. In vitro, SD-FRE significantly promoted the translocation and expression of glucose transporter 4 (GLUT4) in L6 cells, which was significantly inhibited by Compound C (AMPK inhibitor), but not by Wortmannin (PI3K inhibitor) or Gö6983 (PKC inhibitor). These results indicated that SD-FRE enhanced GLUT4 expression and translocation to the plasma membrane via the AMPK pathway and finally resulted in an increase of glucose uptake. In vivo, using a spontaneously type 2 diabetic model, KK-Ay mice received intragastric administration of SD-FRE for 4 weeks. As a consequence, SD-FRE significantly alleviated the hyperglycemia, glucose intolerance, insulin resistance and hyperlipidemia in these mice. Hepatic steatosis, islet hypertrophy and larger adipocyte size were observed in KK-Ay mice. However, these pathological changes were effectively relieved by SD-FRE treatment. SD-FRE promoted GLUT4 expression and activated AMPK phosphorylation in insulin target tissues (muscle, adipose tissue and liver) of KK-Ay mice, thus facilitating glucose utilization to ameliorate insulin resistance. Regulation of ACC phosphorylation and PPARγ were also involved in the antidiabetic effects of SD-FRE. Taken together, these findings indicated that SD-FRE has the potential to alleviate type 2 diabetes.

Casticin suppresses the carcinogenesis of small cell lung cancer H446 cells through activation of AMPK/FoxO3a signaling.

Casticin, a natural polymethoxyflavone isolated from A.annua, V.trifolia, and V.agnus‑castus induces apoptosis in cancer cells by activating FoxO3a. However, whether casticin inhibits invitro carcinogenesis and cancer stem cell (CSC) characteristics, and whether casticin activates FoxO3a in small cell lung cancer (SCLC) cells remain unclear. We here demonstrated that casticin decreased sphere‑ and colony‑formation capabilities, and downregulated uPAR and CD133 in second‑generation spheres, which were considered as lung cancer stem‑like cells (LCSLCs), from SCLC H446 cells, in a concentration‑dependent manner. In addition, casticin dose‑dependently elevated the phosphorylation levels of AMPK and ACC, and reduced p‑FoxO3a expression. The above effects were attenuated by AMPK knockdown with small interfering RNAs (siRNAs). FoxO3a silencing resulted in decreased protein expression of FoxO3a, increased invitro carcinogenesis and CSC characteristics, with no appreciable effects on AMPK and ACC phosphorylation, and displayed similar activities to those neutralizing the effects of casticin on invitro carcinogenesis and CSC characteristics. These findings reveal a novel mechanism for regulating AMPK/FoxO3a signaling in response to casticin, suggesting a new strategy for SCLC therapy by targeting cancer stem‑like cells.

Abstract 5873: BAY-3827, a selective inhibitor of AMPK for the evaluation of the role of AMPK in Myc-dependent tumors

Abstract The AMP-activated protein kinase (AMPK) is a sensor of the energy status in the cells, playing a key role in controlling their metabolism. For many years, AMPK was mainly perceived as a tumor suppressor in agreement with being a component of the LKB1 tumor suppressor cascade, which inhibits mTORC1. However, in the last few years, some studies suggested that AMPK might actually exert a pro-tumorigenic role in certain contexts. For instance, Liu and colleagues demonstrated that dysregulated MYC expression renders tumor cells sensitive to AMPK depletion (Liu et al, 2012. Nature). The authors showed that, due to their increased anabolism, MYC-dependent cells rely on AMPK to restore ATP levels and to prevent an energy crisis that results in apoptosis and cell death. Here we report the discovery of a new lead structure for the inhibition of AMPK by biochemical high throughput screening. The optimization of this lead structure towards potency and selectivity led to the probe compound BAY-3827 and the use of this tool compound to evaluate the therapeutic potential of AMPK inhibition in MYC-dependent tumors. To demonstrate a cellular effect of BAY-3827 an HRTF® assay (Homogeneous Time Resolved Fluorescence, cisbio) for phospho-Acetyl-CoA carboxylase (p-ACC, Ser79), a direct substrate of AMPK, was used. ACC phosphorylation was strongly inhibited by BAY-3827 in COLO 320DM and IMR-32 cells. However, despite its high potency, BAY-3827 failed to inhibit the proliferation of cells with dysregulated c-MYC or N-MYC. In conclusion, we have identified a potent and selective AMPK inhibitor. Despite demonstrated inhibition of AMPK kinase activity, BAY-3827 treatment did not translate into antiproliferative activity in MYC-dependent cells. While we could not confirm our initial hypothesis, one might speculate that inhibition of AMPK might be of therapeutic utility in other biological contexts. Therefore, the availability of potent and selective inhibitors, as described here, will contribute to further insight into the potential of AMPK inhibition as a therapeutic target in cancer. Citation Format: Clara Lemos, Volker K. Schulze, Benjamin Bader, Clara D. Christ, Hans Briem, Oliver Politz, Florian Prinz, Simon Holton, Tobias Heinrich, Julien Lefranc, Philip Lienau, Arne Scholz, Franz von Nussbaum, Carl Friedrich Nising, Dominik Mumberg, Marcus Bauser, Andrea Hägebarth. BAY-3827, a selective inhibitor of AMPK for the evaluation of the role of AMPK in Myc-dependent tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5873.

The Adipose-Derived Insulin Sensitizer Adiponectin Can Activate Intracellular Signaling Independent of the Well Known AdipoR1 or AdipoR2 Receptors

Adiponectin (ADN) is a crucial mediator of insulin sensitivity and vascular health. The discoveries of the adiponectin receptors AdipoR1 and AdipoR2 (R1 and R2) prompted efforts to identify ADN-mimetics. R1 and R2 are especially difficult drug targets due to the complex higher-order structures of ADN as well as challenges in creating receptor knock-out cell lines. We approached R1 and R2 as possible targets beginning with a rigorous validation of the ligand and receptors. ADN preparations from multiple internal and external sources were characterized in physicochemical, cell binding and in vitro assays (pAMPK/pACC and ceramidase). It is important to note that ADN from only one source passed this evaluation. This ADN triggered in vitro activities associated with this protein, including stimulation of phosphorylation of ACC (EC50 = 9.3 ug/ml), calcium influx (EC50 = 2.2 ug/ml), glucose uptake, fatty acid oxidation and ceramidase activity. With a biologically active ADN preparation identified, we strove to understand the interactions of ADN with R1 and R2. However, both R1 and R2 are ubiquitously expressed, complicating the in vitro confirmation of receptor-dependent functional activity. We selected HAP1 cells, an ADN-responsive haploid CML derived line well-suited for gene deletion via CRISPR-Cas9 technology, to generate R1, R2 and R1/R2 deficient cells. Surprisingly, the stimulatory activity of adiponectin in pACC and ceramidase assays in HAP1 cells deficient in R1, R2 or both R1 and R2 were indistinguishable from those in wild type HAP1 cells. In addition, transient overexpression of R1 in HAP1 cells or pretreatment with antibodies to block R1 did not alter their pACC responses to ADN. These data indicate R1 and R2 are not responsible for all the in vitro biological activity attributed to ADN and suggest that there must be other yet unidentified receptors for ADN. Disclosure J.W. Gunnet: Employee; Self; Janssen Research &amp; Development. W. Li: None. Y. Wang: None. J.A. Chavez: None. M. Husovsky: None. R. Meng: None. W. Lang: None. J.R. Jeyaseelan: Employee; Self; Janssen Pharmaceuticals, Inc.. G.W. Caldwell: None. S. Edavettal: Employee; Self; Janssen Research &amp; Development.

Proscillaridin A induces apoptosis and suppresses non-small-cell lung cancer tumor growth via calcium-induced DR4 upregulation

Non-small-cell lung cancer (NSCLC) is the predominant histological type of lung cancer and is characterized by the highest mortality and incidence rates among these types of malignancies. Cardiac glycosides, a class of natural products, have been identified as a potential type of chemotherapeutic agent. This study aims to investigate the anti-cancer effects and the mechanisms of action of Proscillaridin A (P.A) in NSCLC cells. In vitro sodium–potassium pump (Na+/K+ ATPase) enzyme assays indicated that P.A is a direct Na+/K+ ATPase inhibitor. P.A showed potent cytotoxic effects in NSCLC cells at nanomolar levels. Treatment mechanism studies indicated that P.A elevated Ca2+ levels, activated the AMPK pathway and downregulated phosphorylation of ACC and mTOR. Subsequently, P.A increased death receptor 4 (DR4) expression and downregulated NF–κB. Interestingly, P.A selectively suppressed EGFR activation in EGFR mutant cells but not in EGFR wild-type cells. In vivo, P.A significantly suppressed tumor growth in nude mice compared to vehicle-treated mice. Compared with the Afatinib treatment group, P.A displayed less pharmaceutical toxicity, as the body weight of mice treated with P.A did not decrease as much as those treated with Afatinib. Consistent changes in protein levels were obtained from western blotting analysis of tumors and cell lines. Immunohistochemistry analysis of the tumors from P.A-treated mice showed a significant suppression of EGFR phosphorylation (Tyr 1173) and reduction of the cell proliferation marker Ki-67. Taken together, our results suggest that P.A is a promising anti-cancer therapeutic candidate for NSCLC.

Sulforaphane attenuates bisphenol A-induced 3T3-L1 adipocyte differentiation through cell cycle arrest

Bisphenol A (BPA) may be a critical risk factor for metabolic disorders including obesity and diabetes. Sulforaphane is known to inhibit adipocyte differentiation and induce adipocyte lipolysis. This study sought to investigate the possible effects of sulforaphane on BPA-induced adipocyte differentiation in 3T3-L1 cells. During the preadipocytes differentiation process, sulforaphane suppressed the expression of early adipogenic factors, PPARγ and C/EBPα, induced by BPA in 3T3-L1 cells. Based on cell cycle analysis, sulforaphane mediated the inhibition of mitotic clonal expansion via cell cycle arrest at the G0/G1 phase. The compound inhibited cell cycle progression by suppressing cell cycle regulators such as cyclin D1 and pRb and by increasing p21 and p27, cell cycle inhibitors. Moreover, sulforaphane activated phosphorylation of AMPK and ACC and decreased that of ERK1/2 and Akt. Sulforaphane exerts inhibitory effects on BPA-induced adipocyte differentiation in 3T3-L1 cells. Sulforaphane could be adipogenic properties for improving environmental pollutants.

Combination Treatment of Deep Sea Water and Fucoidan Attenuates High Glucose-Induced Insulin-Resistance in HepG2 Hepatocytes.

Insulin resistance (IR) plays a central role in the development of several metabolic diseases, which leads to increased morbidity and mortality rates, in addition to soaring health-care costs. Deep sea water (DSW) and fucoidans (FPS) have drawn much attention in recent years because of their potential medical and pharmaceutical applications. This study investigated the effects and mechanisms of combination treatment of DSW and FPS in improving IR in HepG2 hepatocytes induced by a high glucose concentration. The results elucidated that co-treatment with DSW and FPS could synergistically repress hepatic glucose production and increase the glycogen level in IR-HepG2 cells. In addition, they stimulated the phosphorylation levels of the components of the insulin signaling pathway, including tyrosine phosphorylation of IRS-1, and serine phosphorylation of Akt and GSK-3β. Furthermore, they increased the phosphorylation of AMPK and ACC, which in turn decreased the intracellular triglyceride level. Taken together, these results suggested that co-treatment with DSW and FPS had a greater improving effect than DSW or FPS alone on IR. They might attenuate IR by targeting Akt/GSK-3β and AMPK pathways. These results may have some implications in the treatment of metabolic diseases.

EGCG stimulates the recruitment of brite adipocytes, suppresses adipogenesis and counteracts TNF-α-triggered insulin resistance in adipocytes.

The global rise in obesity and type 2 diabetes has precipitated the need for therapeutic intervention in the arsenal against adiposity. (-)-Epigallocatechin-3-gallate (EGCG), a major nutraceutical component of green tea, has been regarded as a nutraceutical that has powerful antioxidant and anti-obesity bioactivities. In the present study, we showed that EGCG alleviates intracellular lipid accumulation markedly, and the inhibitory effect was largely limited to the early stage of adipocyte differentiation. Consistently, EGCG notably evoked the phosphorylation of AMPK and ACC and blunted the key enzymes of de novo lipogenesis. Interestingly, EGCG elicited iWAT-preadipocyte-derived mature white adipocyte beiging via activating thermogenic gene Ucp1 expression and mitochondrial biogenesis. Furthermore, our results also revealed that EGCG attenuated insulin signaling pathway blockage induced by TNF-α through the abrogation of redox imbalance and mitochondrial dysfunction. These findings indicate that EGCG is capable of suppressing adipogenesis and evoking white adipocyte beiging and therefore it may potentially serve as a novel approach to combat obesity.

PTP1B inhibitors from the seeds of Iris sanguinea and their insulin mimetic activities via AMPK and ACC phosphorylation

To find PTP1B inhibitors from natural products, two new compounds (1 and 2), along with nine known compounds (3–11), were isolated from a methanol-soluble extract of Iris sanguinea seeds. The structures of compounds 1 and 2 were determined based on extensive spectroscopic data analysis including UV, IR, NMR, and MS. The IC50 value of compound 5 on protein tyrosine phosphatase 1B (PTP1B) inhibitory activity is 7.30±0.88µM with a little activity compared to the IC50 values of the tested positive compound. Compound 5 significantly enhanced glucose uptake and activation of pACC, pAMPK and partially Erk1/2 signaling. These results suggest that compound 5 from Iris sanguinea seeds are utilized as both PTP1B inhibitors and regulators of glucose uptake. These beneficial effects could be applied to treat metabolic diseases such as diabetes and obesity.

Positive regulation of prostate cancer cell growth by lipid droplet forming and processing enzymes DGAT1 and ABHD5

BackgroundNeoplastic cells proliferate rapidly and obtain requisite building blocks by reprogramming metabolic pathways that favor growth. Previously, we observed that prostate cancer cells uptake and store lipids in the form of lipid droplets, providing building blocks for membrane synthesis, to facilitate proliferation and growth. Mechanisms of lipid uptake, lipid droplet dynamics and their contribution to cancer growth have yet to be defined. This work is focused on elucidating the prostate cancer-specific modifications in lipid storage pathways so that these modified gene products can be identified and therapeutically targeted.MethodsTo identify genes that promote lipid droplet formation and storage, the expression profiles of candidate genes were assessed and compared between peripheral blood mononuclear cells and prostate cancer cells. Subsequently, differentially expressed genes were inhibited and growth assays performed to elucidate their role in the growth of the cancer cells. Cell cycle, apoptosis and autophagy assays were performed to ascertain the mechanism of growth inhibition.ResultsOur results indicate that DGAT1, ABHD5, ACAT1 and ATGL are overexpressed in prostate cancer cells compared to PBMCs and of these overexpressed genes, DGAT1 and ABHD5 aid in the growth of the prostate cancer cells. Blocking the expression of both DGAT1 and ABHD5 results in inhibition of growth, cell cycle block and cell death. DGAT1 siRNA treatment inhibits lipid droplet formation and leads to autophagy where as ABHD5 siRNA treatment promotes accumulation of lipid droplets and leads to apoptosis. Both the siRNA treatments reduce AMPK phosphorylation, a key regulator of lipid metabolism. While DGAT1 siRNA reduces phosphorylation of ACC, the rate limiting enzyme in de novo fat synthesis and triggers phosphorylation of raptor and ULK-1 inducing autophagy and cell death, ABHD5 siRNA decreases P70S6 phosphorylation, leading to PARP cleavage, apoptosis and cell death. Interestingly, DGAT-1 is involved in the synthesis of triacylglycerol where as ABHD5 is a hydrolase and participates in the fatty acid oxidation process, yet inhibition of both enzymes similarly promotes prostate cancer cell death.ConclusionInhibition of either DGAT1 or ABHD5 leads to prostate cancer cell death. Both DGAT1 and ABHD5 can be selectively targeted to block prostate cancer cell growth.

Diallyl trisulfide exerts cardioprotection against myocardial ischemia-reperfusion injury in diabetic state, role of AMPK-mediated AKT/GSK-3β/HIF-1α activation.

Diallyl trisulfide (DATS), the major active ingredient in garlic, has been reported to confer cardioprotective effects. However, its effect on myocardial ischemia-reperfusion (MI/R) injury in diabetic state and the underlying mechanism are still unknown. We hypothesize that DATS reduces MI/R injury in diabetic state via AMPK-mediated AKT/GSK-3β/HIF-1α activation. Streptozotocin-induced diabetic rats received MI/R surgery with or without DATS (20mg/kg) treatment in the presence or absence of Compound C (Com.C, an AMPK inhibitor, 0.25mg/kg) or LY294002 (a PI3K inhibitor, 5mg/kg). We found that DATS significantly improved heart function and reduced myocardial apoptosis. Additionally, in cultured H9c2 cells, DATS (10μM) also attenuated simulated ischemia-reperfusion injury. We found that AMPK and AKT/GSK-3β/HIF-1α signaling were down-regulated under diabetic condition, while DATS markedly increased the phosphorylation of AMPK, ACC, AKT and GSK-3β as well as HIF-1α expression in MI/R-injured myocardium. However, these protective actions were all blunted by Com.C administration. Additionally, LY294002 abolished the stimulatory effect of DATS on AKT/GSK-3β/HIF-1α signaling without affecting AMPK signaling. While 2-methoxyestradiol (a HIF-1α inhibitor) reduced HIF-1α expression without affecting AKT/GSK-3β signaling. Taken together, these data showed that DATS protected against MI/R injury in diabetic state by attenuating cellular apoptosis via AMPK-mediated AKT/GSK-3β/HIF-1α signaling. Its cardioprotective effect deserves further study.