Glucose Uptake Activity Research Articles

Downregulated miRNA-324-5p aggravates neuronal injury induced by oxygen-glucose deprivation via modulating RAN.

Differentially expressed miRNAs in the GEO profile of ischemic stroke were analyzed to clarify the specific role of microRNA-324-5p (miRNA-324-5p) in ischemic stroke and the potential mechanism. After screening out miRNA-324-5p, its level in peripheral blood of stroke patients and in vitro oxygen-glucose deprivation (OGD)-induced primary rat neurons was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Regulatory effects of miRNA-324-5p on viability, and apoptosis of OGD-induced neurons were evaluated by CCK-8 and Annexin V fluorescein isothiocyanate (FITC)/propidium iodide (PI) staining, respectively. Glucose uptake and caspase-3 activity in OGD-induced neurons transfected with miRNA-324-5p mimics or inhibitor were also examined. The binding of miRNA-324-5p to its target gene RAN was analyzed by dual-luciferase reporter gene assay and western blot analysis. By analyzing the data of GSE46266 profile, miRNA-324-5p expression was shown markedly lower in MCAO rats relative to controls. Identically, we also observed the downregulated miRNA-324-5p in peripheral blood of stroke patients and in vitro OGD-induced primary neurons. Overexpression of miRNA-324-5p accelerated viability, induced apoptosis and strengthened glucose uptake ability of OGD-induced neurons. Knockdown of miRNA-324-5p, conversely, obtained the opposite results. Furthermore, we confirmed the binding of miRNA-324-5p to RAN, the target gene that was negatively regulated by miRNA-324-5p. Importantly, RAN overexpression partially reversed the regulatory effect of miRNA-324-5p on viability and glucose uptake of OGD-induced neurons. miRNA-324-5p is downregulated after ischemic stroke, which aggravates the disease condition by inhibiting neuronal proliferation and glucose uptake via upregulating RAN.

PipeNig®-FL, a Fluid Extract of Black Pepper (Piper Nigrum L.) with a High Standardized Content of Trans-β-Caryophyllene, Reduces Lipid Accumulation in 3T3-L1 Preadipocytes and Improves Glucose Uptake in C2C12 Myotubes.

Trans-β-caryophyllene (BCP) is a natural sesquiterpene hydrocarbon with several important pharmacological activities, including antioxidant, anti-inflammatory, anticancer, and cardioprotective functions. These properties are mainly due to its selective interaction with the peripherally expressed cannabinoid receptor 2. In addition, BCP activates peroxisome proliferated activator receptors α and γ and inhibits the Toll-like receptor signaling pathway. Given the growing scientific interest in BCP, the aim of our study was to investigate the metabolic effects of a black pepper extract (PipeNig®-FL), containing a high standardized content of BCP. In particular our interest was focused on its potential activity on lipid accumulation and glucose uptake. The extract PipeNig®-FL was chemically characterized by gas chromatography–mass spectrometry (GC–MS) and gas chromatography with flame-ionization detection (GC–FID), confirming a high content (814 mg/g) of BCP. Experiments were performed on 3T3-L1 preadipocytes and on C2C12 myotubes. Lipid content following 3T3-L1 adipogenic differentiation was quantified with AdipoRed fluorescence staining. Glucose uptake and GLUT4 membrane translocation were studied in C2C12 myotubes with the fluorescent glucose analog 2-NBDG and by immunofluorescence analysis. Here we show that PipeNig®-FL reduces 3T3-L1 adipocyte differentiation and lipid accumulation. Moreover, acute exposure of C2C12 myotubes to PipeNig®-FL improves glucose uptake activity and GLUT4 migration. Taken together, these results reveal interesting and novel properties of BCP, suggesting potential applications in the prevention of lipid accumulation and in the improvement of glucose uptake.

Biology-oriented Drug Synthesis (BIODS), Structural Characterization and Bioactivities of Novel Albendazole Derivatives

Background:Albendazole is a drug, belongs to the family of benzimidazole, and used as an anthelmintic agent in both human and veterinary medicine. It is marketed as Albenza which is used for the treatment of a variety of parasitic worm infestations such as roundworms, tapeworms, and flukes. In recent past, we have reported various classes of compounds as anti-glycating agents, in continuation of Biology-oriented Drug Synthesis (BIODS), seventeen albendazole derivatives 2-18 were synthesized evaluated for yeast glucose uptake activity.Methods:In the present study, Albendazole (2 g, 7.5 mmol), potassium hydroxide (3 g) were dissolved in ethanol (50 mL) into a 250 mL round-bottomed flask and refluxed for 48 h. TLC (ethyl acetate: hexane, 6:4) was monitored in order to check the reaction progress. After completion, the reaction mixture was dried under air and washed with an excess of distilled water. Precipitates were dried and crystallized from ethanol. The product was characterized by EI-MS and 1H-NMR.Results:Our present study showed that all compounds showed a varying degree of yeast glucose uptake activity ranging between IC50 = 51.41-258.40 µM, compared with standard metronidazole (IC50 = 41.86 ± 0.09 µM). This study has identified a series of potential leads for anti-glycating agents.Conclusion:Biology-oriented drug synthesis and in vitro yeast glucose uptake activity of albendazole derivatives gave rise to a number of lead molecule such as 3 (IC50 = 59.37 ± 0.26 µM), 5 (IC50 = 59.70 ± 0.32 µM), 6 (IC50 = 60.78 ± 0.54 µM), 8 (IC50 = 54.61 ± 0.20 µM), 16 (IC50 = 56.57 ± 0.04 µM) and 14 (IC50 = 51.41 ± 1.25 µM).

Flow-Encoded Oxygen Control to Track the Time-Dependence of Molecular Changes Induced by Static or Cycling Hypoxia

Detecting the effects of low oxygen on cell function is often dependent on monitoring the expression of a number of hypoxia markers. The time dependence of the appearance and stability of these markers varies between cell lines. Assessing cellular marker dynamics is also critical to determining how quickly cells respond to transient changes in oxygen levels that occurs with cycling hypoxia. We fabricated a manifold designed to use flow-encoding to produce sequential changes in gas mixtures delivered to a permeable-bottom 96-well plate. We show how this manifold and plate design can be used to expose cells to either static or cycling hypoxic conditions for eight different time periods thereby facilitating the study of the time-response of cells to altered oxygen environments. Using this device, we monitored the time-dependence of molecular changes in human PANC-1 pancreatic carcinoma and Caco-2 colon adenocarcinoma cells exposed to increasing periods of static or cycling hypoxia. Using immunohistochemistry, both cell lines show detectable levels of the marker protein hypoxia-inducible factor-1α (HIF-1α) after 3 h of exposure to static hypoxia. Cycling hypoxia increased the expression level of HIF-1α compared to static hypoxia. Both static and cycling hypoxia also increased glucose uptake and aldehyde dehydrogenase activity. This new device offers a facile screening approach to determine the kinetics of cellular alterations under varying oxygen conditions.

Hypoglycemic Activity of Curculigo latifolia on Insulin and Glucose Uptake Activities in in vitro

Hypoglycemic Activity of <i>Curculigo latifolia</i> on Insulin and Glucose Uptake Activities in in vitro

Discrimination between Human Colorectal Neoplasms with a Dual-Recognitive Two-Photon Probe.

Colorectal cancer is a major cause of cancer-related deaths worldwide. Histologic diagnosis using biopsy samples of colorectal neoplasms is the most important step in determining the treatment methods, but these methods have limitations in accuracy and effectiveness. Herein, we report a dual-recognition two-photon probe and its application in the discrimination between human colorectal neoplasms. The probe is composed of two monosaccharides, d-glucosamine and β-d-galactopyranoside, in a fluorophore for the monitoring of both glucose uptake and β-gal hydrolysis. In vitro/cell imaging studies revealed the excellent selectivity and sensitivity of the probe for glucose transporter-mediated glucose uptake and β-gal activity. Cancer-specific uptake was monitored by increased fluorescence intensity, and additional screening of cancer cells was achieved by changes in emission ratio owing to the higher activity of β-gal. Using human colon tissues and two-photon microscopy, we found that the plot of intensity versus ratio can accurately discriminate between colorectal neoplasms in the order of cancer progression (normal, adenoma, and carcinoma).

Neuregulin-1 triggers GLUT4 translocation and enhances glucose uptake independently of insulin receptor substrate and ErbB3 in neonatal rat cardiomyocytes

During stress conditions such as pressure overload and acute ischemia, the myocardial endothelium releases neuregulin-1β (NRG-1), which acts as a cardioprotective factor and supports recovery of the heart. Recently, we demonstrated that recombinant human (rh)NRG-1 enhances glucose uptake in neonatal rat ventricular myocytes via the ErbB2/ErbB4 heterodimer and PI3Kα. The present study aimed to further elucidate the mechanism whereby rhNRG-1 activates glucose uptake in comparison to the well-established insulin and to extend the findings to adult models. Combinations of rhNRG-1 with increasing doses of insulin did not yield any additive effect on glucose uptake measured as 3H-deoxy-d-glucose incorporation, indicating that the mechanisms of the two stimuli are similar. In c-Myc-GLUT4-mCherry-transfected neonatal rat cardiomyocytes, rhNRG-1 increased sarcolemmal GLUT4 by 16-fold, similar to insulin. In contrast to insulin, rhNRG-1 did not phosphorylate IRS-1 at Tyr612, indicating that IRS-1 is not implicated in the signal transmission. Treatment of neonatal rats with rhNRG-1 induced a signaling response comparable with that observed in vitro, including increased ErbB4-pTyr1284, Akt-pThr308 and Erk1/2-pThr202/Tyr204. In contrast, in adult cardiomyocytes rhNRG-1 only increased the phosphorylation of Erk1/2 without having any significant effect on Akt and AS160 phosphorylation and glucose uptake, suggesting that rhNRG-1 function in neonatal cardiomyocytes differs from that in adult cardiomyocytes. In conclusion, our results show that similar to insulin, rhNRG-1 can induce glucose uptake by activating the PI3Kα-Akt-AS160 pathway and GLUT4 translocation. Unlike insulin, the rhNRG-1-induced effect is not mediated by IRS proteins and is observed in neonatal, but not in adult rat cardiomyocytes.

Screening for metabolic syndrome application of a herring by-product hydrolysate after its separation by electrodialysis with ultrafiltration membrane and identification of novel anti-inflammatory peptides

The seafood industry is an important producer of by-products which can represent 50% of fish and contain valuable molecules for the human health. The search of bioactive peptides has increased since the last decades and marine organisms revealed a high richness. A herring milt hydrolysate has been separated by electrodialysis with ultrafiltration membrane (EDUF). Four fractions were collected: two anionic and two cationic, with respectively higher presence of acidic amino acids for the first ones and basic amino acids for the seconds. The higher migration rate was reported for the cationic, revealing the higher presence of cationic peptides and free basic amino acids in the initial milt herring hydrolysate. Both cationic fractions have decreased the inducible nitric oxide synthase (iNOS) activation in the macrophage cells at 1 ng/ml (−11.65% and −13.22%) and 100 pg/ml (−17.58% and 15.51%), demonstrating their in vitro anti-inflammatory effect. The oxygen radical absorbance capacity (ORAC) test revealed an antioxidant activity of 460.67 µmolTE/g for the initial hydrolysate, 386.20 µmolTE/g after EDUF separation and 343.49 µmolTE/g for the anionic fraction A50. No effects on the glucose uptake activity was reported for any fraction. In addition, two new cationic peptide sequences (IVPAS and FDKPVSPLL) from herring milt hydrolysate were identified and demonstrated an in vitro anti-inflammatory activity. This study highlighted the potential use of milt herring hydrolysate for prevention of the metabolic syndrome.

PFKFB3 inhibition reprograms malignant pleural mesothelioma to nutrient stress-induced macropinocytosis and ER stress as independent binary adaptive responses

The metabolic signatures of cancer cells are often associated with elevated glycolysis. Pharmacological (PFK158 treatment) and genetic inhibition of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), a critical control point in the glycolytic pathway, decreases glucose uptake, ATP production, and lactate dehydrogenase activity and arrests malignant pleural mesothelioma (MPM) cells in the G0/G1 phase to induce cell death. To overcome this nutrient stress, inhibition of PFKFB3 activity led to an escalation in endoplasmic reticulum (ER) activity and aggravated ER stress mostly by upregulating BiP and GADD153 expression and activation of the endocytic Rac1-Rab5-Rab7 pathway resulting in a unique form of cell death called “methuosis” in both the sarcomatoid (H28) and epithelioid (EMMeso) cells. Transmission electron microscopy (TEM) analysis showed the formation of nascent macropinocytotic vesicles, which rapidly coalesced to form large vacuoles with compromised lysosomal function. Both immunofluorescence microscopy and co-immunoprecipitation analyses revealed that upon PFKFB3 inhibition, two crucial biomolecules of each pathway, Rac1 and Calnexin interact with each other. Finally, PFK158 alone and in combination with carboplatin-inhibited tumorigenesis of EMMeso xenografts in vivo. Since most cancer cells exhibit an increased glycolytic rate, these results provide evidence for PFK158, in combination with standard chemotherapy, may have a potential in the treatment of MPM.

Multi-Omics Studies Demonstrate Toxoplasma gondii-Induced Metabolic Reprogramming of Murine Dendritic Cells.

Toxoplasma gondii is capable of actively invading almost any mammalian cell type including phagocytes. Early events in phagocytic cells such as dendritic cells are not only key to establishing parasite infection, but conversely play a pivotal role in initiating host immunity. It is now recognized that in addition to changes in canonical immune markers and mediators, alteration in metabolism occurs upon activation of phagocytic cells. These metabolic changes are important for supporting the developing immune response, but can affect the availability of nutrients for intracellular pathogens including T. gondii. However, the interaction of T. gondii with these cells and particularly how infection changes their metabolism has not been extensively investigated. Herein, we use a multi-omics approach comprising transcriptomics and metabolomics validated with functional assays to better understand early events in these cells following infection. Analysis of the transcriptome of T. gondii infected bone marrow derived dendritic cells (BMDCs) revealed significant alterations in transcripts associated with cellular metabolism, activation of T cells, inflammation mediated chemokine and cytokine signaling pathways. Multivariant analysis of metabolomic data sets acquired through non-targeted liquid chromatography mass spectroscopy (LCMS) identified metabolites associated with glycolysis, the TCA cycle, oxidative phosphorylation and arginine metabolism as major discriminants between control uninfected and T. gondii infected cells. Consistent with these observations, glucose uptake and lactate dehydrogenase activity were upregulated in T. gondii infected BMDC cultures compared with control BMDCs. Conversely, BMDC mitochondrial membrane potential was reduced in T. gondii-infected cells relative to mitochondria of control BMDCs. These changes to energy metabolism, similar to what has been described following LPS stimulation of BMDCs and macrophages are often termed the Warburg effect. This metabolic reprogramming of cells has been suggested to be an important adaption that provides energy and precursors to facilitate phagocytosis, antigen processing and cytokine production. Other changes to BMDC metabolism are evident following T. gondii infection and include upregulation of arginine degradation concomitant with increased arginase-1 activity and ornithine and proline production. As T. gondii is an arginine auxotroph the resultant reduced cellular arginine levels are likely to curtail parasite multiplication. These results highlight the complex interplay of BMDCs and parasite metabolism within the developing immune response and the consequences for adaptive immunity and pathogen clearance.

Synthesis of Pyridinyl-benzo[d]imidazole/Pyridinyl-benzo[d]thiazole Derivatives and their Yeast Glucose Uptake Activity In Vitro

Background:Diabetes is the primary cause of fatality and disability all over the world, in recent past, we have reported various classes of compounds as anti-glycating agents and we have also reported benzimidazole and benzothiazole derivatives as a potential class of anti-glycating agents. This encouraged us to evaluate the pyridinyl benzimidazole/pyridinyl benzothiazole derivatives 1-27 for yeast glucose uptake activity.Methods:In the present study, an equimolar mixture of pyridine carboxaldehyde derivatives (1 mmol) and sodium metabisulphite (1 mmol) in DMF (10 mL) was stirred for 10 to 15 min, followed by addition of o-phenylene diamine/2-aminothiophenol (1 mmol) into it and refluxed for 3 h. The progress of the reaction was monitored by TLC. After completion, the reaction mixture was poured into crushed ice. Precipitates were formed which were collected by filtration to produce compounds 1-27 in good yields. Recrystallization from methanol yielded pure crystals.Results:Our present study showed that all compounds showed a varying degree of yeast glucose uptake activity in the range IC50 = 36.43-272.20 µM, compared to standard metronidazole (IC50 = 41.86 ± 0.09 µM). Compounds 5 (IC50 = 38.14 ± 0.17 µM), 6 (IC50 = 40.23 ± 0.20 µM), and 7 (IC50 = 36.43 ± 0.02 µM) showed an excellent yeast glucose uptake activity better than the standard.Conclusion:Pyridinyl benzimidazole/pyridinyl benzothiazole derivatives 1-27 were synthesized, structurally characterized, and evaluated for in vitro yeast glucose uptake activity. Compounds 5 (IC50 = 38.14 ± 0.17 µM), 6 (IC50 = 40.23 ± 0.20 µM), and 7 (IC50 = 36.43 ± 0.02 µM) demonstrated potent yeast glucose uptake activity as compared to standard metronidazole (IC50 = 41.86 ± 0.09 µM). This study identified a number of potential lead molecules which can be helpful in lowering the blood glucose level in hyperglycemia.

AN IN VITRO STUDY OF SYZYGIUM CUMINI SEED EXTRACT ON GLUCOSE UPTAKE ACTIVITY IN L-6 CELL LINES

Diabetes mellitus is the most common endocrine disorder. The plant Syzygium cumini has been used in traditional medicine for the treatment of diabetes. The present study investigated the effect of ethanol extract of S. cumini seeds on uptake of glucose by L-6 rat skeletal muscle cells. S. cumini seeds were extracted with varying solvents and quantitative phytochemical analysis was carried out, ethanol extract of seeds exhibited higher content of tested phytochemicals. The effect of different concentrations (300µg/ml – 1000µg/ml) of ethanol extract of seeds were studied on glucose uptake activity of L-6 rat skeletal muscle cells. It was observed that with the increase in concentration, the glucose uptake activity was also increased. The results of the study supports and demonstrates the antidiabetic potential of ethanol seed extracts of Syzygium cumini utilizing in vitro model. KEY WORDS: Diabetes mellitus, Syzygium cumini, phytochemicals, glucose uptake, L-6 cells

Coumarin tethered cyclic imides as efficacious glucose uptake agents and investigation of hit candidate to probe its binding mechanism with human serum albumin

A series of novel coumarin-cyclic imide conjugates (1a–1j) were designed and synthesized to evaluate their glucose uptake activity by insulin resistant liver hepatocyte carcinoma (HepG2) cells through 2-NBDG uptake assay. Compounds (1a–1j) were characterised using various analytical methods such as 1H NMR, 13C NMR, IR, GC–MS, elemental and single-crystal X-ray diffraction techniques. Compounds (1a–1j) exhibited 85.21 – 65.80% of glucose uptake and showed low level of cytotoxicity towards human embryonic kidney cells (HEK-293) indicating good selectivity and safety profile. Compound 1f was identified as a hit candidate exhibiting 85.21% of glucose uptake which was comparable with standard antidiabetic drug Metformin (93.25% glucose uptake). Solution stability study under physiological pH conditions ≈ (3.4 – 8.7), indicates that compound 1f is sufficiently stable at varied pH conditions and thereby compatible with bio-physiological environments. Interaction of 1f with human serum albumin (HSA) were also studied which quantifies that compound 1f binds with HSA efficiently through facile binding reaction in solution. Fluorescence, UV–vis spectrophotometry and molecular modeling methodologies were employed for studying the interaction mechanism of compound 1f with protein.

Methylamine Activates Glucose Uptake in Human Adipocytes Without Overpassing Action of Insulin or Stimulating its Secretion in Pancreatic Islets.

Background: Methylamine, a natural soluble amine present in foods, is known to be a substrate of primary amine oxidase (PrAO) widely expressed in animal tissues. Methylamine has been reported to activate glucose transport in fat cells and to facilitate glucose disposal in rabbits but the interests and limits of such insulin-mimicking actions have not been further explored. This work aimed to perform a preclinical study of the inter-individual variations of these biological properties to study the putative link between PrAO activity and insulin resistance. Methods: Methylamine was tested on human adipocyte preparations and in rabbit pancreatic islets to determine its influence on glucose uptake and insulin release, respectively. PrAO activity and related responses were determined in adipose tissues obtained from two cohorts of non-obese and obese women. Results: Adipose tissue PrAO activity was negatively correlated with insulin resistance in high-risk obese women. PrAO-dependent activation of glucose uptake was negatively correlated with body mass index and reflected the decrease of insulin responsiveness of human fat cells with increasing obesity. Methylamine exhibited antilipolytic properties in adipocytes but was unable to directly activate insulin secretion in isolated pancreatic islets. Conclusions: PrAO activation by its substrates, e.g., methylamine, increases glucose utilization in human adipocytes in a manner that is linked to insulin responsiveness. Methylamine/PrAO interaction can therefore contribute to adipose tissue enlargement but should be considered as potentially useful for diabetes prevention since it could limit lipotoxicity and facilitate glucose handling, at the expense of favoring healthy fat accumulation.

Arsenic impairs GLUT1 trafficking through the inhibition of the calpain system in lymphocytes

Exposure to arsenic is associated with increased risk of developing insulin resistance and type 2 diabetes. The proteases calpain-1 (CAPN1), calpain-2 (CAPN2) and calpain-10 (CAPN10) and their endogenous inhibitor calpastatin (CAST) regulate glucose uptake in skeletal muscle and adipocytes. We investigated whether arsenic disrupts GLUT1 trafficking and function through calpain inhibition, using lymphocytes as a cell model. Lymphocytes from healthy subjects were treated with 0.1 or 1 μM of sodium arsenite for 72 h and challenged with 3.9 or 11.1 mM of glucose. Our results showed that arsenite inhibited GLUT1 trafficking, glucose uptake, and calpain activity in the presence of 11.1 mM of glucose. These correlated with a decrease in the autolytical fragment of 50 kDa of CAPN1 and increased levels of CAST, but there were no changes in CAPN2 and CAPN10. We used a cell-free system to evaluate the effect of arsenite over CAPN1, finding that arsenite induced CAPN1 autolysis. To confirm that calpains are involved in GLUT1 trafficking and glucose uptake in lymphocytes, we generated stable CAPN1 or CAPN10 knockdowns in Jurkat cells using short hairpin RNA (shRNA). CAPN1 knockdown induced glucose uptake, while CAPN10 knockdown diminished glucose uptake, which correlated with a significant reduction of calpain activity after the pulse with 11.1 mM of glucose. These data showed that CAPN10 was responsible for the induction of calpain activity after the challenge with 11.1 mM of glucose and that CAPN1 and CAPN10 regulate glucose uptake in lymphocytes. Altogether, our results suggest that arsenite impairs GLUT1 trafficking and function through calpain dysregulation.

The biflavonoids as protein tyrosine phosphatase 1B inhibitors from Selaginella uncinata and their antihyperglycemic action

Nine biflavonoids (1–9) were isolated from ethanolic extract of Selaginella uncinata (Desv.) Spring. Their structures were determined by spectra analysis. Compounds 1–9 were classified into four types according to the connection styles of the two flavonoid parts. Among them, 1 was elucidated as a new compound, while 4 was one with a new configuration. All isolates exhibited inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) in an enzyme assay with IC50 values ranging from 4.6 to 16.1 μM, and the relationship between the structures and activities was discussed. Docking simulations of these compounds demonstrated they had tight binding capacities towards the allosteric site of PTP1B. Additionally, the glucose uptake activities of 1–9 were evaluated in insulin-resistant HepG2 cells, while the effect of 1 on the activation of IRS-1/PI3K/Akt pathway was revealed by Western Blot analysis.

Abstract 2658: PFKFB3 inhibition reprograms malignant pleural mesothelioma to glycolytic stress-induced macropinocytosis and ER stress as independent binary adaptive responses

Abstract The metabolic signatures of cancer cells are often associated with elevated glycolysis which promotes alteration in cellular bioenergetics. 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), a critical control point in the glycolytic pathway has emerged as a potential anti-cancer target associated with many aspects of neoplastic progression. Pharmacological (PFK158 treatment) and genetic inhibition of PFKFB3 activity, decreases glucose uptake, ATP production, and lactate dehydrogenase activity and inhibits cell proliferation in vitro by arresting the cells in the G0/G1 phase induced cell death in malignant pleural mesothelioma (MPM). It induces an early response of increased macropinocytosis and drastic endosomal vacuolization to overcome the nutrient stress both in sarcomatoid (H28) and epithelioid (EMMeso) MPM cells. Inhibition of PFKFB3 leads to the activation of the endocytic Rac1-Rab5-Rab7 pathway resulting in a unique form of cell death called “methuosis”. Transmission Electron Microscopy analysis showed that pharmacological and genetic inhibition of PFKFB3 activity leads to the formation of nascent macropinocytotic vesicles, which rapidly coalesced to form large vacuoles with compromised lysosomal function. Confocal microscopy revealed F-actin and α-tubulin disassembly leading to the disruption of cell structure integrity. In parallel, PFKFB3 expression inversely modulates endoplasmic reticulum (ER) stress in MPM. Pharmacological and genetic inhibition of PFKFB3 led to an escalation in ER activity and aggravated ER stress mostly by upregulating BiP and GADD153 expression levels. However, EHT1864, a Rac1 inhibitor, could not rescue MPM cells from ER stress, suggesting that the activation of macropinocytosis and ER stress are a result of two independent PFKFB3 modulated adaptive responses. Both immunofluorescence microscopy and co-immunoprecipitation analyses revealed that the two crucial biomolecules of each pathway, Rac1 and Calnexin, interact with each other only at the later stages of PFKFB3 inhibition. Finally, PFK158, in a combination of with CBPt, demonstrated a significant reduction in tumor weight in mesothelin overexpressed EMMeso xenograft model. Since most cancer cells exhibit an increased glycolytic rate, these results provide evidence for PFK158, in combination with standard chemotherapy, may have a potential in the treatment of MPM. Citation Format: Sayantani Sarkar Bhattacharya, Ling Jin, Debarshi Roy, Deokbeom Jung, Prabhu Thirusangu, Yinan Xiao, Julie Staub, Julian Molina, Viji Shridhar. PFKFB3 inhibition reprograms malignant pleural mesothelioma to glycolytic stress-induced macropinocytosis and ER stress as independent binary adaptive responses [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 2658.

Abstract 1852: Down-regulation of PRMT6 drives Warburg effect through ERK induced relocalization of PKM2 to promote tumorigenicity and sorafenib resistance in hepatocellular carcinoma

Abstract Cancer cells have a high dependence of glycolysis for ATP production, especially under hypoxic environment. Metabolic reprogramming in cancer drives an increased glycolytic rate that supports maximal production of nutrients for tumorigenesis. Our group has recently identified the post-translational modification enzyme, protein arginine methyltransferase 6 (PRMT6) to be frequently down-regulated and to exhibit a tumour suppressive effect in maintenance of cancer stemness in hepatocellular carcinoma (HCC) (Chan LH et al. Cell Reports 2018). Our current study finds transcriptome and metabolome profiling of HCC cells with PRMT6 repressed to exhibit enrichment of genes and metabolites involved in glycolysis. In vitro, PRMT6 negatively regulates glycolysis, glucose uptake, lactate production and pyruvate kinase activity in HCC cell lines and patient-derived organoids. Our previous work found PRMT6 to interfere with RAS/RAF binding by directly binding to CRAF and methylating arginine100 residue. Supporting the importance of PRMT6-mediated CRAF methylation, we find overexpression of catalytic inactive PRMT6 to exhibit no effect on glycolysis. MEK/ERK, known downstream effectors of RAS/RAF signalling, has been shown to induce nuclear PKM2 localization. Consistently, we find modulation of PRMT6 to negatively regulate ERK and PKM2 expression and localization. Rescue experiments involving the ERK inhibitor U0126 and shPKM2 further substantiate the importance of ERK/PKM2-mediated glucose metabolic reprogramming in HCC cells with PRMT6 suppressed. Functionally, inhibition of glycolysis by 2-deoxyglucose sensitized PRMT6 knockdown cells to sorafenib treatment in vitro and attenuated tumor growth in vivo. In addition, we also find PRMT6 expression to be regulated via hypoxia by binding of RE1-silencing transcription factor to the promoter region. Rescue experiments by re-expressing PRMT6 under hypoxic conditions further support the involvement of PRMT6 in driving glycolysis in oxygen deprived environments. Our work uncovers a critical function for PRMT6 in driving Warburg effect through regulating expression and localization of PKM2 via post-translational modification of CRAF, thereby promoting HCC initiation and sorafenib resistance. Citation Format: Tin-Lok Wong, Lok-Hei Chan, Stephanie Ma. Down-regulation of PRMT6 drives Warburg effect through ERK induced relocalization of PKM2 to promote tumorigenicity and sorafenib resistance in hepatocellular carcinoma [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 1852.

Antidiabetic Activities of Korean Red Pine (Pinus densiflora) Inner Bark Extracts

This study was carried out to investigate the potential of Korean red pine (Pinus densiflora) inner bark extracts as an antidiabetic agent. The ethyl acetate soluble fraction of the bark extracts was chromatographed on a Sephadex LH-20 column to yield five compounds, which structures were elucidated by NMR spectroscopy. The isolated compounds were (+)-catehin, (−)-epicatechin, taxifolin, taxifolin-3′-O-β-D-(+)-glucose and ñ-courmaric acid. The antidiabetic activity of the different fractions, including the crude extracts and isolated compounds, was evaluated by β-cells insulin secretion and glucose uptake in skeletal muscle cells. The insulin secretion was 128% for taxifolin at 25 μg/mL. However, the other samples had no effect on this test. For the glucose uptake activity assay, 1 μM insulin and 2 mM metformin were used as controls. Both the crude extract and taxifolin showed relatively low activity values, but the other samples yielded glucose uptake values over 260%. ρ-courmaric acid showed the highest uptake (270%). The results confirmed that Korean red pine extracts may be used as a hypoglycemic agent.

Exophiarin, an isocoumarin from the fungus Exophiala sp. with antihyperglycemic activity

Chemical characterization of ethyl acetate extract of Exophiala sp. has afforded the isolation of three compounds including a new isocoumarin named exophiarin (1). Exophiala sp. was obtained from the soil containing dumped organic waste (litter). Initially, LC-UV-MS analysis of the extract of Exophiala sp. revealed the presence of a new compound having molecular weight 438 (1) and previously reported TPI-2 and TPI-5. The novelty was established using advanced database search comprising of biological source, molecular weight and UV profile. 1D, 2D NMR and HRMS data have been used for structure elucidation. Exophiarin with TPI-2 and TPI-5 have displayed moderate improvement in glucose uptake activity when tested in rat skeletal muscle cell line L6.