Stimulation Of Glucose Metabolism Research Articles

Mitigating Hyperglycaemic Oxidative Stress in HepG2 Cells: The Role of Carica papaya Leaf and Root Extracts in Promoting Glucose Uptake and Antioxidant Defence

Background/Objectives: Diabetes often goes undiagnosed, with 60% of people in Africa unaware of their condition. Type 2 diabetes mellitus (T2DM) is associated with insulin resistance and is treated with metformin, despite the undesirable side effects. Medicinal plants with therapeutic potential, such as Carica papaya, have shown promising anti-diabetic properties. This study explored the role of C. papaya leaf and root extracts compared to metformin in reducing hyperglycaemia-induced oxidative stress and their impact on liver function using HepG2 as a reference. Methods: The cytotoxicity was assessed through the MTT assay. At the same time, glucose uptake and metabolism (ATP and ∆Ψm) in HepG2 cells treated with C. papaya aqueous leaf and root extract were evaluated using a luminometry assay. Additionally, antioxidant properties (SOD2, GPx1, GSH, and Nrf2) were measured using qPCR and Western blot following the detection of MDA, NO, and iNOS, indicators of free radicals. Results: The MTT assay showed that C. papaya extracts did not exhibit toxicity in HepG2 cells and enhanced glucose uptake compared to the hyperglycaemic control (HGC) and metformin. The glucose levels in C. papaya-treated cells increased ATP production (p < 0.05), while the ∆Ψm was significantly increased in HGR1000-treated cells (p < 0.05). Furthermore, C. papaya leaf extract upregulated GPx1 (p < 0.05), GSH, and Nrf2 gene (p < 0.05), while SOD2 and Nrf2 proteins were reduced (p > 0.05), ultimately lowering ROS (p > 0.05). Contrarily, the root extract stimulated SOD2 (p > 0.05), GPx1 (p < 0.05), and GSH levels (p < 0.05), reducing Nrf2 gene and protein expression (p < 0.05) and resulting in high MDA levels (p < 0.05). Additionally, the extracts elevated NO levels and iNOS expression (p < 0.05), suggesting potential RNS activation. Conclusion: Taken together, the leaf extract stimulated glucose metabolism and triggered ROS production, producing a strong antioxidant response that was more effective than the root extract and metformin. However, the root extract, particularly at high concentrations, was less effective at neutralising free radicals as it did not stimulate Nrf2 production, but it did maintain elevated levels of SOD2, GSH, and GPx1 antioxidants.

Lithium Enhances Hippocampal Glucose Metabolism in an In Vitro Mice Model of Alzheimer's Disease.

Impaired cerebral glucose metabolism is an early event that contributes to the pathogenesis of Alzheimer’s disease (AD). Importantly, restoring glucose availability by pharmacological agents or genetic manipulation has been shown to protect against Aβ toxicity, ameliorate AD pathology, and increase lifespan. Lithium, a therapeutic agent widely used as a treatment for mood disorders, has been shown to attenuate AD pathology and promote glucose metabolism in skeletal muscle. However, despite its widespread use in neuropsychiatric disorders, lithium’s effects on the brain have been poorly characterized. Here we evaluated the effect of lithium on glucose metabolism in hippocampal neurons from wild-type (WT) and APPSwe/PS1ΔE9 (APP/PS1) mice. Our results showed that lithium significantly stimulates glucose uptake and replenishes ATP levels by preferential oxidation of glucose through glycolysis in neurons from WT mice. This increase was also accompanied by a strong increase in glucose transporter 3 (Glut3), the major carrier responsible for glucose uptake in neurons. Similarly, using hippocampal slices from APP-PS1 mice, we demonstrate that lithium increases glucose uptake, glycolytic rate, and the ATP:ADP ratio in a process that also involves the activation of AMPK. Together, our findings indicate that lithium stimulates glucose metabolism and can act as a potential therapeutic agent in AD.

Impact of PCSK9 on CTRP9-Induced Metabolic Effects in Adult Rat Cardiomyocytes.

The adipocytokine adiponectin and its structural homologs, the C1q/TNF-related proteins (CTRPs), increase insulin sensitivity, fatty acid oxidation and mitochondrial biogenesis. Adiponectin- and CTRP-induced signal transduction has been described to involve the adiponectin receptors and a number of co-receptors including the Low density lipoprotein receptor-related protein 1 (LRP1). LRP1 is another target of the proprotein convertase subtilisin/kexin-9 (PCSK9) in addition to the LDL-receptor (LDL-R). Here, we investigated the influence of PCSK9 on the metabolic effects of CTRP9, the CTRP with the highest homology to adiponectin. Knockdown of LRP1 in H9C2 cardiomyoblasts blunts the effects of CTRP9 on signal transduction and mitochondrial biogenesis, suggesting its involvement in CTRP9-induced cellular effects. Treatment of adult rat cardiomyocytes with recombinant PCSK9 but not knockdown of endogenous PCSK9 by siRNA results in a strong reduction in LRP1 protein expression and subsequently reduces the mitochondrial biogenic effect of CTRP9. PCSK9 treatment (24 h) blunts the effects of CTRP9-induced signaling cascade activation (AMP-dependent protein kinase, protein kinase B). In addition, the stimulating effects of CTRP9 on cardiomyocyte mitochondrial biogenesis and glucose metabolism (GLUT-4 translocation, glucose uptake) are largely blunted. Basal fatty acid (FA) uptake is strongly reduced by exogenous PCSK9, although protein expression of the PCSK9 target CD36, the key regulator of FA transport in cardiomyocytes, is not altered. In addition, only minor effects of PCSK9 were observed on CTRP9-induced FA uptake or the expression of genes involved in FA metabolism or uptake. Finally, this CTRP9-induced increase in CD36 expression occurs independent from LRP1 and LDL-R. In conclusion, PCSK9 treatment influences LRP1-mediated signaling pathways in cardiomyocytes. Thus, therapeutic PCSK9 inhibition may provide an additional benefit through stimulation of glucose metabolism and mitochondrial biogenesis in addition to the known lipid-lowering effects. This could be an important beneficial side effect in situations with impaired mitochondrial function and reduced metabolic flexibility thereby influencing cardiac function.

Testosterone activates glucose metabolism through AMPK and androgen signaling in cardiomyocyte hypertrophy

BackgroundTestosterone regulates nutrient and energy balance to maintain protein synthesis and metabolism in cardiomyocytes, but supraphysiological concentrations induce cardiac hypertrophy. Previously, we determined that testosterone increased glucose uptake—via AMP-activated protein kinase (AMPK)—after acute treatment in cardiomyocytes. However, whether elevated glucose uptake is involved in long-term changes of glucose metabolism or is required during cardiomyocyte growth remained unknown. In this study, we hypothesized that glucose uptake and glycolysis increase in testosterone-treated cardiomyocytes through AMPK and androgen receptor (AR).MethodsCultured cardiomyocytes were stimulated with 100 nM testosterone for 24 h, and hypertrophy was verified by increased cell size and mRNA levels of β-myosin heavy chain (β-mhc). Glucose uptake was assessed by 2-NBDG. Glycolysis and glycolytic capacity were determined by measuring extracellular acidification rate (ECAR).ResultsTestosterone induced cardiomyocyte hypertrophy that was accompanied by increased glucose uptake, glycolysis enhancement and upregulated mRNA expression of hexokinase 2. In addition, testosterone increased AMPK phosphorylation (Thr172), while inhibition of both AMPK and AR blocked glycolysis and cardiomyocyte hypertrophy induced by testosterone. Moreover, testosterone supplementation in adult male rats by 5 weeks induced cardiac hypertrophy and upregulated β-mhc, Hk2 and Pfk2 mRNA levels.ConclusionThese results indicate that testosterone stimulates glucose metabolism by activation of AMPK and AR signaling which are critical to induce cardiomyocyte hypertrophy.

Andrographolide restores glucose uptake in rat hippocampal neurons.

Cerebral glucose hypometabolism is a common pathophysiological characteristic of many neurodegenerative diseases. This metabolic dysfunction includes alterations in glucose transport from the blood into the neurons by the facilitative glucose transporters (GLUTs). Several studies suggest that metabolic disturbances precede clinical symptoms and correlate with disease progression. Some groups have started to explore the use of therapeutic strategies that target decreased cerebral glucose metabolism to promote its availability. We selected Andrographolide (Andro), a natural product obtained from Andrographis paniculate that has both anti-hyperglycemic and anti-diabetic effects. Although it was shown to promote glucose uptake in vivo, the underlying mechanisms remain unclear. Here, we evaluated the acute effects of Andro on glucose transport and metabolism using primary rat hippocampal neuronal cultures. Our results showed that Andro enhances neuronal glucose uptake and stimulates glucose metabolism by inducing GLUT3 and 4 expression in neurons, as well as by promoting glycolysis. We also observed that Andro-mediated effects depend on the activity of AMP-activated protein kinase (AMPK), one of the central regulators of glucose metabolism. Our studies open the possibility to use Andro as a drug to restore glucose levels in neurodegenerative diseases.

Assessment of Serum Concentrations of Omentin-1 in Children with Type 1 Diabetes as Indicator of Insulin Resistance

Background: Omentin-1, a protein produced mainly in visceral adipose tissue. Its function is most likely to increase insulin sensitivity and stimulate glucose metabolism. This effect can be both local and systemic. Objective: To evaluate the concentrations of selected gastric peptide omentin-1 in serum of children with type 1 diabetes, relevant to the disease duration. Patients and Methods: This case control prospective study was conducted during the period from 2018 to 2020. This study was carried out in Endocrinology Unit and Outpatient Clinic at Pediatric Department, Zagazig University Hospital. The sample size was 85 (17 in every group). Serum omentin-1 level was measured. Results: Cases were significantly higher than control regarding FBS, PPBS and HA1c. Cases were significantly higher than control as it was distributed as 426.04 ± 137.6 and 103.21 ± 32.5 respectively. Significant AUC with cutoff > 191.7 and 100.0% sensitivity and specificity. Regarding FBS & PPBS, control group were significantly lower than other groups but group 4 was significantly higher than other groups regarding PPBS. Regarding HA1c, control group was significantly lower than other groups but groups 1 & 4 were significantly higher than other groups. Concerning omentin, control group was significantly lower than other groups and group 4 was significantly higher than other groups also groups 2 & 3 were significantly higher than group 1. Conclusion: T1DM is a common health problem in the pediatric age group. Omentin-1 level was significantly high in T1DM and its level is strongly correlated to duration and insulin resistance.

Assessment of Serum Concentrations of Omentin-1 in Children with Type 1 Diabetes as Indicator of Insulin Resistance

Background: Omentin-1, a protein produced mainly in visceral adipose tissue. Its function is most likely to increase insulin sensitivity and stimulate glucose metabolism. This effect can be both local and systemic. Objective: To evaluate the concentrations of selected gastric peptide omentin-1 in serum of children with type 1 diabetes, relevant to the disease duration. Patients and Methods: This case control prospective study was conducted during the period from 2018 to 2020. This study was carried out in Endocrinology Unit and Outpatient Clinic at Pediatric Department, Zagazig University Hospital. The sample size was 85 (17 in every group). Serum omentin-1 level was measured. Results: Cases were significantly higher than control regarding FBS, PPBS and HA1c. Cases were significantly higher than control as it was distributed as 426.04 ± 137.6 and 103.21 ± 32.5 respectively. Significant AUC with cutoff > 191.7 and 100.0% sensitivity and specificity. Regarding FBS & PPBS, control group were significantly lower than other groups but group 4 was significantly higher than other groups regarding PPBS. Regarding HA1c, control group was significantly lower than other groups but groups 1 & 4 were significantly higher than other groups. Concerning omentin, control group was significantly lower than other groups and group 4 was significantly higher than other groups also groups 2 & 3 were significantly higher than group 1. Conclusion: T1DM is a common health problem in the pediatric age group. Omentin-1 level was significantly high in T1DM and its level is strongly correlated to duration and insulin resistance.

LncRNA LINP1 regulates acute myeloid leukemia progression via HNF4α/AMPK/WNT5A signaling pathway.

LncRNAs play critical roles in various pathophysiological and biological processes, such as protein translation, RNA splicing, and epigenetic modification. Indeed, abundant evidences demonstrated that lncRNA act as competing endogenous RNAs (ceRNAs) to participate in tumorigenesis. However, little is known about the underlying function of lncRNA in nonhomologous end joining (NHEJ) pathway 1 (LINP1) in pediatric and adolescent acute myeloid leukemia (AML). The expression of LINP1 was examined in AML patient samples by qRT-PCR. Cell proliferation was examined by CCK-8 and Edu assays. β-Galactosidase senescence assay, mGlucose uptake assay, lactate production assay, and Gene Ontology (GO) analysis were performed for functional analysis. We found that LINP1 was significantly overexpressed in AML patients at diagnosis, whereas downregulated after complete remission (CR). Furthermore, knockdown of LINP1 expression remarkably suppressed glucose uptake and AML cell maintenance. Mechanistically, LINP1 was found to inhibit the glucose metabolism by suppressing the expression of HNF4a. Both LINP1 and HNF4a knockdown reduced the expression levels of AMPK phosphorylation and WNT5A, indicating for the first time that LINP1 strengthened the HNF4a-AMPK/WNT5A signaling pathway involved in cell glucose metabolism modulation and AML cell survival. Taken together, our results indicated that LINP1 promotes the malignant phenotype of AML cells and stimulates glucose metabolism, which can be regarded as a potential prognostic marker and therapeutic target for AML.

Increased glycolysis mediates Wnt7b-induced bone formation.

Wingless/integrated (Wnt) signaling has emerged as a major mechanism for promoting bone formation and a target pathway for developing bone anabolic agents against osteoporosis. However, the downstream events mediating the potential therapeutic effect of Wnt proteins are not fully understood. Previous studies have indicated that increased glycolysis is associated with osteoblast differentiation in response to Wnt signaling, but direct genetic evidence for the importance of glucose metabolism in Wnt-induced bone formation is lacking. Here, we have generated compound transgenic mice to overexpress Wnt family member 7B (Wnt7b) transiently in the osteoblast lineage of postnatal mice, with or without concurrent deletion of the glucose transporter 1 (Glut1), also known as solute carrier family 2, facilitated glucose transporter member 1. Overexpression of Wnt7b in 1-mo-old mice for 1 wk markedly stimulated bone formation, but the effect was essentially abolished without Glut1, even though transient deletion of Glut1 itself did not affect normal bone accrual. Consistent with the in vivo results, Wnt7b increased Glut1 expression and glucose consumption in the primary culture of osteoblast lineage cells, and deletion of Glut1 diminished osteoblast differentiation in vitro. Thus, Wnt7b promotes bone formation in part through stimulating glucose metabolism in osteoblast lineage cells.-Chen, H., Ji, X., Lee, W.-C., Shi, Y., Li, B., Abel, E. D., Jiang, D., Huang, W., Long, F. Increased glycolysis mediates Wnt7b-induced bone formation.

Effects of Recovery Mode during High Intensity Interval Training on Glucoregulatory Hormones and Glucose Metabolism in Response to Maximal Exercise.

Catecholamines [adrenaline (A) and noradrenaline (NA)] are known to stimulate glucose metabolism at rest and in response to maximal exercise. However, training and recovery mode can alter theses hormones. Thus our study aims to examine the effects of recovery mode during High-intensity Interval Training (HIIT) on glucoregulatory hormone responses to maximal exercise in young adults. Twenty-four male enrolled in this randomized study, assigned to: control group (eg, n=6), and two HIIT groups: intermittent exercise (30 s run/30 s recovery) with active (arg, n=9) or passive (prg, n=9) recovery, arg and prg performed HIIT 3 times weekly for 7 weeks. Before and after HIIT, participants undergo a Maximal Graded Test (MGT). Plasma catecholamines, glucose, insulin, growth hormone (Gh) and cortisol were determined at rest, at the end of MGT, after 10 and 30 min of recovery. After training V02max and Maximal Aerobic Velocity (MAV) increased significantly (p<0.05) in arg. After HIIT and in response to MGT plasma glucose increase significantly (p=0.008) lesser in arg compared to prg whereas insulin concentrations were similar. The glucose/insulin ratio was significantly lower at MGT end (p=0.033) only in arg after training. After HIIT, in response to MGT, plasma A, NA, cortisol and Gh concentrations were significantly higher only in arg (p<0.05). HIIT using active recovery is beneficial for aerobic fitness, plasma glucose and glucoregulatory hormones better than HIIT with passive recovery. These findings suggest that HIIT with active recovery may improve some metabolic and hormonal parameters in young adults.

Taraxerol, a pentacyclic triterpenoid, from Abroma augusta leaf attenuates diabetic nephropathy in type 2 diabetic rats

Persistent hyperglycaemia coupled with inflammation plays an important role in the pathogenesis of diabetic nephropathy (DN). Present study examined the therapeutic potential of taraxerol isolated from the methanol extract of Abroma augusta leaf against DN using rodent model of type 2 diabetes (T2D). T2D was experimentally induced by high fat diet and a single low-single dose of streptozotocin (35mg/kg, i.p.). Accumulation of serum creatinine, urea, and uric acid, activation of lactate dehydrogenase and creatinin kinase, and release of urinary albumin represented the glomerular damage and the progression of nephropathy in T2D rats. Taraxerol (20mg/kg, p.o.) treatment significantly reinstated the aforementioned changes in biochemical parameters near to normalcy. Molecular mechanism studies demonstrated an impaired signaling cascade, IRS1/PI3K/Akt/AMPK/GLUT4/GSK3β, of glucose metabolism in the skeletal muscle and increase in serum levels of pro-inflammatory cytokines, CRP and MCP1 in T2D rats. Activation of polyol pathway, enhanced production of AGEs, up-regulation of NF-κB/PKCs/PARP signaling, and renal fibrosis was also observed in T2D rats. Taraxerol (20mg/kg, p.o.) treatment stimulated glucose metabolism in skeletal muscle, regulated blood glycaemic status and lipid profile in the sera, reduced the secretion of pro-inflammatory cytokines, and restored the renal physiology in T2D rats. Histological assessments were also in agreement with the above findings. Molecular docking study again supported the probable interactions of taraxerol with PKCβ, PKCδ, NF-κB, PARP, PI3K, IRS, Akt and AMPK. In silico ADME study predicted the drug-likeness character of taraxerol. Results suggest a possibility of taraxerol to be a new therapeutic agent for DN in future.

Protocatechuic Acid, a Phenolic from Sansevieria roxburghiana Leaves, Suppresses Diabetic Cardiomyopathy via Stimulating Glucose Metabolism, Ameliorating Oxidative Stress, and Inhibiting Inflammation.

Persistent hyperglycemia, impairment of redox status and establishment of inflammatory pathophysiology integrally play important role in the pathogenesis of diabetic cardiomyopathy (DC). Present study examined the therapeutic potential of protocatechuic acid isolated from the Sansevieria roxburghiana rhizomes against DC employing rodent model of type 2 diabetes (T2D). T2D was induced by high fat diet + a low-single dose of streptozotocin (35 mg/kg, i.p.). T2D rats exhibited significantly (p < 0.01) high fasting blood glucose level. Alteration in serum lipid profile (p < 0.01) and increased levels of lactate dehydrogenase (p < 0.01) and creatine kinase (p < 0.01) in the sera of T2D rats revealed the occurrence of hyperlipidemia and diabetic pathophysiology. A significantly (p < 0.01) high levels of serum C-reactive protein and pro-inflammatory mediators revealed the establishment of inflammatory occurrence in T2D rats. Besides, significantly high levels of troponins in the sera revealed the establishment of cardiac dysfunctions in T2D rats. However, protocatechuic acid (50 and 100 mg/kg, p.o.) treatment could significantly reverse the changes in serum biochemical parameters related to cardiac dysfunctions. Molecular mechanism studies demonstrated impairment of signaling cascade, IRS1/PI3K/Akt/AMPK/p 38/GLUT4, in glucose metabolism in the skeletal muscle of T2D rats. Significant (p < 0.01) activation of polyol pathway, enhanced production of AGEs, oxidative stress and up-regulation of inflammatory signaling cascades (PKC/NF-κB/PARP) were observed in the myocardial tissue of T2D rats. However, protocatechuic acid (50 and 100 mg/kg, p.o.) treatment could significantly (p < 0.05–0.01) stimulate glucose metabolism in skeletal muscle, regulated glycemic and lipid status, reduced the secretion of pro-inflammatory cytokines, and restored the myocardial physiology in T2D rats near to normalcy. Histological assessments were also in agreement with the above findings. In silico molecular docking study again supported the interactions of protocatechuic acid with different signaling molecules, PI3K, IRS, Akt, AMPK PKC, NF-κB and PARP, involved in glucose utilization and inflammatory pathophysiology. In silico ADME study predicted that protocatechuic acid would support the drug-likeness character. Combining all, results would suggest a possibility of protocatechuic acid to be a new therapeutic agent for DC in future.

Abstract 56: Suppression of 6-Phosphofructo-2-Kinase (PFKFB3) for the treatment of breast cancer

Abstract Glucose uptake by tumors is stimulated by estradiol (E2) administration in estrogen receptor positive (ER+) breast cancer patients. Notably, this E2-induced metabolic flare is predictive of the clinical effectiveness of anti-estrogens and, therefore, downstream metabolic regulators of E2 are expected to have utility as anti-breast cancer agents. Although the stimulation of glucose metabolism by E2 has been demonstrated, relatively little is known about the precise downstream effectors required for E2 to stimulate glucose metabolism in breast cancer. We have demonstrated that the expression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), a key regulator of the glycolytic flux, is elevated in breast cancer lymph node metastases and that exposure of ER+ human MCF-7 and T-47D breast cancer cells to E2 causes a rapid increase in 14C-glucose uptake and glycolysis that is coincident with an induction of PFKFB3 mRNA (via ER binding to its promoter), protein expression and the intracellular concentration of its product, fructose-2,6-bisphosphate (F26BP). Importantly, we also found that selective inhibition of PFKFB3 expression and activity using siRNA or a PFKFB3 inhibitor, PFK158, markedly reduces the E2-mediated increase in F26BP, 14C-glucose uptake and glycolysis. In the current study, we sought to determine if co-administration of PFK158, with ICI 182,780 (fulvestrant), would offer a greater anti-tumor effect. In unpublished results, we demonstrated that the combination of the anti-estrogen, fulvestrant, with PFK158 results in greater regressions of MCF-7 xenografts than either drug alone in athymic BALB/c mice. In addition to regulating glucose metabolism, PFKFB3 has been found to be a regulator of the cell cycle via cyclin dependent kinases. We postulated that the combination of PFK158 with the newly FDA-approved CDK4/6 inhibitor palbociclib may result in a synergistic decrease in tumor cell growth. We found that exposure of breast cancer cells to palbociclib and PFK158 causes a synergistic increase in cell cycle arrest and apoptotic cell death. In addition, we observed a synergistic decrease in phospho-retinoblastoma protein (Rb), a key downstream target of CDK4/6. Importantly, we found that the combination of PFK158 and palbociclib did not cause an increase in cell cycle arrest or apoptosis in normal human mammary epithelial cells. Taken together, these data indicate that PFKFB3 inhibitors such as PFK158 may have clinical utility for the treatment of ER+ breast cancers when combined with anti-estrogen agents and/or CDK4/6 inhibitors. Citation Format: Yoannis Imbert-Fernandez, Amy Clem, Brian Clem, Gilles Tapolsky, Sucheta Telang, Jason Chesney. Suppression of 6-Phosphofructo-2-Kinase (PFKFB3) for the treatment of breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 56.

Regulation of cytokine gene expression by orosomucoid in neonatal swine adipose tissue.

BackgroundPorcine adipose tissue expresses orosomucoid (ORM1) mRNA, a protein with anti-inflammatory and immunomodulatory properties. Previous research has demonstrated that porcine ORM1 can reduce insulin stimulated glucose metabolism in porcine adipose tissue in vitro. The present study was designed to examine the preweaning ontogeny of ORM1 mRNA abundance in porcine subcutaneous adipose and to determine if ORM1 can regulate mRNA abundance of inflammatory cytokines that contribute to insulin resistance in primary cultures derived from neonatal porcine subcutaneous adipose tissue. Cultures were differentiated in vitro and subsequently the adipocyte containing cultures were incubated for 24 h with 0–5000 ng porcine ORM1/mL medium. Cultures were then harvested, total RNA extracted for use in reverse transcription and the mRNA abundance of cytokine mRNA quantified by real-time PCR.ResultsORM1 mRNA abundance within neonatal adipose tissue does not change from d 1 to d 21 of age and is a very small fraction relative to liver mRNA abundance. The ORM1 mRNA level in porcine adipocytes and stromal-vascular cells are similar (P > 0.05). Treatment with ORM1 did not affect TNFα (tumor necrosis factor α) mRNA level (P > 0.05), while interleukin 6 (IL6) mRNA abundance was reduced 32 % at 1,000 ng ORM1/mL (P < 0.01). However, TNFα protein content in the cell culture media was reduced by ORM1 treatment (5,000 ng/mL, P < 0.05), whereas ORM1 had no detectable effect on the media content of IL6 (P > 0.05). The reduction of macrophage migration inhibitory factor (MIF) mRNA abundance by ORM1 was dose dependent (P < 0.01). Monocyte chemotactic protein (MCP) mRNA level was reduced 27 % by 1,000 ng ORM1/mL (P < 0.05).ConclusionsThe data suggest that ORM1 has limited effects TNFα, IL6, MIF or MCP expression at the concentrations tested. Secondly, these cytokines do not appear to contribute to the reported insulin resistance induced by ORM1 in porcine adipose tissue in vitro as an increase in the abundance of these inflammatory cytokines would be predicted during an insulin resistant state.

Abstract A84: Regulation of 6-phosphofructo-2-kinase (PFKFB3) by estradiol and implications for the treatment of ER+ metastatic breast cancer

Abstract Estradiol (E2) administered to estrogen receptor positive (ER+) breast cancer patients stimulates glucose uptake by tumors. This E2-induced metabolic flare is predictive of the clinical effectiveness of anti-estrogens and downstream metabolic regulators of E2 are expected to have utility as targets for the development of anti-breast cancer agents. While the stimulation of glucose metabolism by E2 has been demonstrated, relatively little is known about the precise downstream effectors required for E2 to stimulate glucose metabolism in breast cancer. The family of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatases (PFKFB1-4) control glycolytic flux via their product, fructose-2,6-bisphosphate (F26BP), which activates 6-phosphofructo-1-kinase (PFK-1). We recently demonstrated that PFKFB3 expression is elevated in breast cancer lymph node metastases and that exposure of human MCF-7 and T-47D breast cancer cells to E2 causes a rapid increase in 14C-glucose uptake and glycolysis that is coincident with an induction of PFKFB3 mRNA (via ER binding to its promoter), protein expression and the intracellular concentration of its product, F26BP. Importantly, we also found that selective inhibition of PFKFB3 expression and activity using siRNA or a PFKFB3 inhibitor, PFK158, markedly reduces the E2-mediated increase in F26BP, 14C-glucose uptake and glycolysis. In the current study, we sought to determine if co-administration of PFK158, with ICI 182,780 (fulvestrant), would offer a greater anti-tumor effect. In unpublished results, we demonstrated that the combination of the anti-estrogen, fulvestrant, with PFK158 results in greater regressions of MCF-7 xenografts than either drug alone in athymic BALB/C mice. In addition to regulating glucose metabolism, PFKFB3 has been found to be a regulator of the cell cycle via cyclin dependent kinases. We postulated that the combination of PFK158 with the newly FDA-approved CDK4/6 inhibitor palbociclib may result in a synergistic increase in apoptosis. We found that PFK158 markedly increased apoptosis caused by palbociclib in MCF-7 breast cancer cells but not in normal human mammary epithelial cells. Taken together, these data indicate that PFKFB3 inhibitors such as PFK158 may have clinical utility for the treatment of ER+ breast cancers when combined with anti-estrogen agents and/or CDK4/6 inhibitors. Citation Format: Yoannis Imbert-Fernandez, Brian Clem, Gilles Tapolsky, Jason Chesney. Regulation of 6-phosphofructo-2-kinase (PFKFB3) by estradiol and implications for the treatment of ER+ metastatic breast cancer. [abstract]. In: Proceedings of the AACR Special Conference: Metabolism and Cancer; Jun 7-10, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(1_Suppl):Abstract nr A84.

Proteomics annotate therapeutic properties of a traditonal Tibetan medicine – Tsantan Sumtang targeting and regulating multiple perturbed pathways

Ethnopharmacological relevanceTsantan Sumtang is a traditional Tibetan medicine, which has been traditionally used as medicine for the treatment of cardiopyretic disease which is similar to angina. However, the precise and comprehensive mechanism of it pretreatment remain elusive, so in this study, we used proteomics to systematically analyse the therapeutic mechanism of it. Materal and methodsRats were divided into three groups (n=6): Tsantan Sumtang group (2g/kg), the model group, the control group (distilled water, 10ml/kg). Drugs were treated once a day for 20 days. After the last administration of drug, left anterior descending coronary artery ligation in vivo was performed. 5 days latter, the hearts were harvested and we applied HPLC- MS/MS using an isobaric TMTs proteomics technology to analyse the differentially expressed proteins among groups. ResultsWe comfirmed from the data that 752 proteins were differentially expressed in model group when compared with the control group, 314 proteins showed the recovery of the values by Tsantan Sumtang treatment. The differential proteins were analysed by gene ontology, cellular pathways and clustering analyses, most of them were metabolic enzymes. These included glycolytic enzymes, enzymes implicated in fatty acids oxidation and the tricarboxylic acid cycle, various subunits of different mitochondrial electron transfer chain complexes, as well as enzymes involved in antioxidation system. ConclusionTsantan Sumtang can target and regulate multiple metabolic perturbed pathways, especially it can partially inhibite fatty acid β-oxidation, stimulate glucose metabolism, oxidative phosphorylation and ATP utilization to protect the injured heart. This helped us to understand the molecular therapeutic mechanisms of Tsantan Sumtang on mycardial ischemia.

Abstract 4478: 6-Phosphofructo-2-Kinase (PFKFB3): At the crossroads of resistance to targeted cancer therapies

Abstract Targeted cancer therapies that block the growth and spread of cancer by interfering with specific onco-proteins are limited by signaling mechanisms that drive intrinsic and acquired resistance. In particular, the MAPK and the PI3K/AKT pathways have been found to both reduce response rates to these agents and to mediate the acquisition of resistance via mutations that activate both pathways. For example, two recently approved BRAFV600E inhibitors, vemurafenib and dabrafenib, cause dramatic clinical responses in ∼50% of BRAFV600E + melanoma patients but universally become ineffective within 5-6 months as a result of genetic alterations that activate the MAPK and PI3K-AKT pathways, including amplifications in BRAFV600E, loss of PTEN, and activating mutations in NRAS and KRAS, MEK, AKT1/3, PIK3CA and PIK3CG. Several of these mutated signaling proteins stimulate glucose metabolism, required for survival and proliferation, in part by increasing the expression and activity of 6-phosphofructo-2-kinase (PFKFB3). For example, PFKFB3 transcription is induced by HIF-1α (which is increased by BRAFV600E, RAS and MEK), loss of PTEN, and PFKFB3 activity is stimulated by AKT via phosphorylation of serine 461. We postulated that PFKFB3 is an essential downstream target of targeted cancer therapies and that the multitude of mutations and amplifications in signaling pathways that cause resistance to these agents activate PFKFB3. In new studies, we demonstrate that BRAFV600E, estradiol and epidermal growth factor each regulate PFKFB3 expression in melanoma cells, breast cancer cells and NSCLC cells, respectively. Moreover, we find that simultaneous inhibition of these oncoproteins or their co-ligands (i.e. the estrogen and EGF receptors) and PFKFB3 using a novel PFKFB3 inhibitor currently in a phase 1 trial, PFK-158, causes a synergistic increase in apoptosis and cytotoxicity in vitro, suggesting that PFK-158 can overcome the intrinsic resistance to these agents. We then decided to determine if these significant synergies would translate in vivo by investigating them in the A375 and A2058 melanoma preclinical models, and in the MCF-7 ER-dependent breast model. For instance, we compared the anti-tumor effects in A375 melanoma xenograft-bearing mice of: (i) the BRAFV600E inhibitor vemurafenib; (ii) PFK-158; or (iii) the combination of vemurafenib and PFK-158. Although we observed significant tumor growth inhibition with both monotherapies (&amp;gt;80%), we only observed tumor regression with the combination therapy (&amp;gt;50%). Results in these different models will be presented. Taken together, these data demonstrate that the PFKFB3 inhibitor PFK-158 may be able to universally overcome resistance to targeted cancer therapies. Furthermore, we predict that phase 1/2 trials of PFK-158 in combination with targeted cancer agents will yield improvements in objective response rates as well as improvements in progression-free survival. Citation Format: Sucheta Telang, Julie O'Neal, Yoannis Imbert-Fernandez, Brian Clem, Nadiia Lypova, Gilles H. Tapolsky, John Trent, Jason Chesney. 6-Phosphofructo-2-Kinase (PFKFB3): At the crossroads of resistance to targeted cancer therapies. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4478. doi:10.1158/1538-7445.AM2015-4478

Resveratrol increases glycolytic flux in Saccharomyces cerevisiae via a SNF1-dependet mechanism.

Evidence suggests that AMP protein kinase (AMPK) is the main target of the phytochemical resveratrol (RSV) in mammalian cells. Data also indicates that RSV stimulates glucose metabolism; however, the molecular link between RSV and glucose uptake remains unknown. Herein, we provide evidence indicating that RSV stimulates glycolysis via sucrose non-fermenting 1 gene (SNF1, Saccharomyces cerevisiae orthologous of AMPK). S. cerevisiae cultures treated with 30 μM RSV showed an increase in extracellular acidification rate compared to untreated cells, indicating an elevated glycolytic flux. Also, RSV treatment increased transcription levels of two key glycolytic genes, hexokinase 2 (HXK2) and phosphofructokinase 1 (PFK1), as well as production of NADH. Moreover, RSV treatment inhibited mitochondrial respiration when glucose was used as a carbon source. Importantly, the effects of RSV on glycolysis were dependent of SNF1. Taken together, these findings suggest that SNF1 (AMPK in mammalian systems) is the molecular target of RSV in S. cerevisiae.

In vivo cardiac glucose metabolism in the high-fat fed mouse: Comparison of euglycemic–hyperinsulinemic clamp derived measures of glucose uptake with a dynamic metabolomic flux profiling approach

RationaleCardiac metabolism is thought to be altered in insulin resistance and type 2 diabetes (T2D). Our understanding of the regulation of cardiac substrate metabolism and insulin sensitivity has largely been derived from ex vivo preparations which are not subject to the same metabolic regulation as in the intact heart in vivo. Studies are therefore required to examine in vivo cardiac glucose metabolism under physiologically relevant conditions. ObjectiveTo determine the temporal pattern of the development of cardiac insulin resistance and to compare with dynamic approaches to interrogate cardiac glucose and intermediary metabolism in vivo. Methods and resultsStudies were conducted to determine the evolution of cardiac insulin resistance in C57Bl/6 mice fed a high-fat diet (HFD) for between 1 and 16 weeks. Dynamic in vivo cardiac glucose metabolism was determined following oral administration of [U-13C] glucose. Hearts were collected after 15 and 60 min and flux profiling was determined by measuring 13C mass isotopomers in glycolytic and tricarboxylic acid (TCA) cycle intermediates. Cardiac insulin resistance, determined by euglycemic–hyperinsulinemic clamp, was evident after 3 weeks of HFD. Despite the presence of insulin resistance, in vivo cardiac glucose metabolism following oral glucose administration was not compromised in HFD mice. This contrasts our recent findings in skeletal muscle, where TCA cycle activity was reduced in mice fed a HFD. Similar to our report in muscle, glucose derived pyruvate entry into the TCA cycle in the heart was almost exclusively via pyruvate dehydrogenase, with pyruvate carboxylase mediated anaplerosis being negligible after oral glucose administration. ConclusionsUnder experimental conditions which closely mimic the postprandial state, the insulin resistant mouse heart retains the ability to stimulate glucose metabolism.

Rod-Derived Cone Viability Factor Promotes Cone Survival by Stimulating Aerobic Glycolysis

Rod-derived cone viability factor (RdCVF) is an inactive thioredoxin secreted by rod photoreceptors that protects cones from degeneration. Because the secondary loss of cones in retinitis pigmentosa (RP) leads to blindness, the administration of RdCVF is a promising therapy for this untreatable neurodegenerative disease. Here, we investigated the mechanism underlying the protective role of RdCVF in RP. We show that RdCVF acts through binding to Basigin-1 (BSG1), a transmembrane protein expressed specifically by photoreceptors. BSG1 binds to the glucose transporter GLUT1, resulting in increased glucose entry into cones. Increased glucose promotes cone survival by stimulation of aerobic glycolysis. Moreover, a missense mutation of RdCVF results in its inability to bind to BSG1, stimulate glucose uptake, and prevent secondary cone death in a model of RP. Our data uncover an entirely novel mechanism of neuroprotection through the stimulation of glucose metabolism.