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Sample records for metformin induces cardioprotection

  1. Fenofibrate plus Metformin Produces Cardioprotection in a Type 2 Diabetes and Acute Myocardial Infarction Model

    PubMed Central

    Oidor-Chan, Víctor Hugo; Hong, Enrique; Pérez-Severiano, Francisca; Montes, Sergio; Torres-Narváez, Juan Carlos; del Valle-Mondragón, Leonardo; Pastelín-Hernández, Gustavo; Sánchez-Mendoza, Alicia

    2016-01-01

    We investigated whether fenofibrate, metformin, and their combination generate cardioprotection in a rat model of type 2 diabetes (T2D) and acute myocardial infarction (AMI). Streptozotocin-induced diabetic- (DB-) rats received 14 days of either vehicle, fenofibrate, metformin, or their combination and immediately after underwent myocardial ischemia/reperfusion (I/R). Fenofibrate plus metformin generated cardioprotection in a DBI/R model, reported as decreased coronary vascular resistance, compared to DBI/R-Vehicle, smaller infarct size, and increased cardiac work. The subchronic treatment with fenofibrate plus metformin increased, compared with DBI/R-Vehicle, total antioxidant capacity, manganese-dependent superoxide dismutase activity (MnSOD), guanosine triphosphate cyclohydrolase I (GTPCH-I) expression, tetrahydrobiopterin : dihydrobiopterin (BH4 : BH2) ratio, endothelial nitric oxide synthase (eNOS) activity, nitric oxide (NO) bioavailability, and decreased inducible NOS (iNOS) activity. These findings suggest that PPARα activation by fenofibrate + metformin, at low doses, generates cardioprotection in a rat model of T2D and AMI and may represent a novel treatment strategy to limit I/R injury in patients with T2D. PMID:27069466

  2. The cardioprotective compound cloxyquin uncouples mitochondria and induces autophagy.

    PubMed

    Zhang, Jimmy; Nadtochiy, Sergiy M; Urciuoli, William R; Brookes, Paul S

    2016-01-01

    Mitochondrial quality control mechanisms have been implicated in protection against cardiac ischemia-reperfusion (IR) injury. Previously, cloxyquin (5-chloroquinolin-8-ol) was identified via phenotypic screening as a cardioprotective compound. Herein, cloxyquin was identified as a mitochondrial uncoupler in both isolated heart mitochondria and adult cardiomyocytes. Additionally, cardiomyocytes isolated from transgenic mice expressing green fluorescent protein-tagged microtubule-associated protein light chain 3 showed increased autophagosome formation with cloxyquin treatment. The autophagy inhibitor chloroquine abolished cloxyquin-induced cardioprotection in both cellular and perfused heart (Langendorff) models of IR injury. Finally, in an in vivo murine left anterior descending coronary artery occlusion model of IR injury, cloxyquin significantly reduced infarct size from 31.4 ± 3.4% to 16.1 ± 2.2%. In conclusion, the cardioprotective compound cloxyquin simultaneously uncoupled mitochondria and induced autophagy. Importantly, autophagy appears to be required for cloxyquin-induced cardioprotection. PMID:26519034

  3. Metformin attenuates ventilator-induced lung injury

    PubMed Central

    2012-01-01

    Introduction Diabetic patients may develop acute lung injury less often than non-diabetics; a fact that could be partially ascribed to the usage of antidiabetic drugs, including metformin. Metformin exhibits pleiotropic properties which make it potentially beneficial against lung injury. We hypothesized that pretreatment with metformin preserves alveolar capillary permeability and, thus, prevents ventilator-induced lung injury. Methods Twenty-four rabbits were randomly assigned to pretreatment with metformin (250 mg/Kg body weight/day per os) or no medication for two days. Explanted lungs were perfused at constant flow rate (300 mL/min) and ventilated with injurious (peak airway pressure 23 cmH2O, tidal volume ≈17 mL/Kg) or protective (peak airway pressure 11 cmH2O, tidal volume ≈7 mL/Kg) settings for 1 hour. Alveolar capillary permeability was assessed by ultrafiltration coefficient, total protein concentration in bronchoalveolar lavage fluid (BALF) and angiotensin-converting enzyme (ACE) activity in BALF. Results High-pressure ventilation of the ex-vivo lung preparation resulted in increased microvascular permeability, edema formation and microhemorrhage compared to protective ventilation. Compared to no medication, pretreatment with metformin was associated with a 2.9-fold reduction in ultrafiltration coefficient, a 2.5-fold reduction in pulmonary edema formation, lower protein concentration in BALF, lower ACE activity in BALF, and fewer histological lesions upon challenge of the lung preparation with injurious ventilation. In contrast, no differences regarding pulmonary artery pressure and BALF total cell number were noted. Administration of metformin did not impact on outcomes of lungs subjected to protective ventilation. Conclusions Pretreatment with metformin preserves alveolar capillary permeability and, thus, decreases the severity of ventilator-induced lung injury in this model. PMID:22827994

  4. Metformin

    MedlinePlus

    ... fda.gov/Drugs/DrugSafety/ucm493244.htm for additional information, including a data summary and a list of metformin-containing drugs.BACKGROUND: Metformin-containing medicines are available by prescription only ...

  5. Metformin

    MedlinePlus

    ... absorb from your food and the amount of glucose made by your liver. Metformin also increases your body's response to insulin, a natural substance that controls the amount of glucose in the blood. Metformin is not used to ...

  6. Metformin prevents methylglyoxal-induced apoptosis of mouse Schwann cells

    SciTech Connect

    Ota, Kimiko; Nakamura, Jiro; Li, Weiguo; Kozakae, Mika; Watarai, Atsuko; Nakamura, Nobuhisa; Yasuda, Yutaka; Nakashima, Eirtaro; Naruse, Keiko; Watabe, Kazuhiko; Kato, Koichi; Oiso, Yutaka; Hamada, Yoji . E-mail: yhama@med.nagoya-u.ac.jp

    2007-05-25

    Methylglyoxal (MG) is involved in the pathogenesis of diabetic complications via the formation of advanced glycation end products (AGEs) and reactive oxygen species (ROS). To clarify whether the antidiabetic drug metformin prevents Schwann cell damage induced by MG, we cultured mouse Schwann cells in the presence of MG and metformin. Cell apoptosis was evaluated using Hoechst 33342 nuclear staining, caspase-3 activity, and c-Jun-N-terminal kinase (JNK) phosphorylation. Intracellular ROS formation was determined by flow cytometry, and AMP-activated kinase (AMPK) phosphorylation was also examined. MG treatment resulted in blunted cell proliferation, an increase in the number of apoptotic cells, and the activation of caspase-3 and JNK along with enhanced intracellular ROS formation. All of these changes were significantly inhibited by metformin. No significant activation of AMPK by MG or metformin was observed. Taken together, metformin likely prevents MG-induced apoptotic signals in mouse Schwann cells by inhibiting the formation of AGEs and ROS.

  7. Metformin Reduces Bleomycin-induced Pulmonary Fibrosis in Mice.

    PubMed

    Choi, Sun Mi; Jang, An Hee; Kim, Hyojin; Lee, Kyu Hwa; Kim, Young Whan

    2016-09-01

    Metformin has anti-inflammatory and anti-fibrotic effects. We investigated whether metformin has an inhibitory effect on bleomycin (BLM)-induced pulmonary fibrosis in a murine model. A total of 62 mice were divided into 5 groups: control, metformin (100 mg/kg), BLM, and BLM with metformin (50 mg/kg or 100 mg/kg). Metformin was administered to the mice orally once a day from day 1. We sacrificed half of the mice on day 10 and collected the bronchoalveolar lavage fluid (BALF) from their left lungs. The remaining mice were sacrificed and analyzed on day 21. The right lungs were harvested for histological analyses. The messenger RNA (mRNA) levels of epithelial-mesenchymal transition markers were determined via analysis of the harvested lungs on day 21. The mice treated with BLM and metformin (50 mg/kg or 100 mg/kg) showed significantly lower levels of inflammatory cells in the BALF compared with the BLM-only mice on days 10 and 21. The histological examination revealed that the metformin treatment led to a greater reduction in inflammation than the treatment with BLM alone. The mRNA levels of collagen, collagen-1, procollagen, fibronectin, and transforming growth factor-β in the metformin-treated mice were lower than those in the BLM-only mice on day 21, although statistical significance was observed only in the case of procollagen due to the small number of live mice in the BLM-only group. Additionally, treatment with metformin reduced fibrosis to a greater extent than treatment with BLM alone. Metformin suppresses the inflammatory and fibrotic processes of BLM-induced pulmonary fibrosis in a murine model. PMID:27510385

  8. Metformin Protects Skeletal Muscle from Cardiotoxin Induced Degeneration

    PubMed Central

    Langone, Francesca; Cannata, Stefano; Fuoco, Claudia; Lettieri Barbato, Daniele; Testa, Stefano; Nardozza, Aurelio Pio; Ciriolo, Maria Rosa; Castagnoli, Luisa; Gargioli, Cesare; Cesareni, Gianni

    2014-01-01

    The skeletal muscle tissue has a remarkable capacity to regenerate upon injury. Recent studies have suggested that this regenerative process is improved when AMPK is activated. In the muscle of young and old mice a low calorie diet, which activates AMPK, markedly enhances muscle regeneration. Remarkably, intraperitoneal injection of AICAR, an AMPK agonist, improves the structural integrity of muscles of dystrophin-deficient mdx mice. Building on these observations we asked whether metformin, a powerful anti-hyperglycemic drug, which indirectly activates AMPK, affects the response of skeletal muscle to damage. In our conditions, metformin treatment did not significantly influence muscle regeneration. On the other hand we observed that the muscles of metformin treated mice are more resilient to cardiotoxin injury displaying lesser muscle damage. Accordingly myotubes, originated in vitro from differentiated C2C12 myoblast cell line, become more resistant to cardiotoxin damage after pre-incubation with metformin. Our results indicate that metformin limits cardiotoxin damage by protecting myotubes from necrosis. Although the details of the molecular mechanisms underlying the protective effect remain to be elucidated, we report a correlation between the ability of metformin to promote resistance to damage and its capacity to counteract the increment of intracellular calcium levels induced by cardiotoxin treatment. Since increased cytoplasmic calcium concentrations characterize additional muscle pathological conditions, including dystrophies, metformin treatment could prove a valuable strategy to ameliorate the conditions of patients affected by dystrophies. PMID:25461598

  9. Adjunctive metformin for antipsychotic-induced hyperprolactinemia: A systematic review.

    PubMed

    Bo, Qi-Jing; Wang, Zhi-Min; Li, Xian-Bin; Ma, Xin; Wang, Chuan-Yue; de Leon, Jose

    2016-03-30

    This systematic review examines adjunctive metformin therapy for the treatment of antipsychotic-induced hyperprolactinemia. A computerized search of databases in Chinese and the international databases in English provided three trials with a total of 325 patients including one randomized clinical trial (RCT) and two observational studies (single-group, before-after design). A meta-analysis could not be conducted. The quality of evidence ranged from "very low" to "moderate". Metformin patients had a significant decrease in serum prolactin level with a mean of 54.6μg/l in the three trials. In the RCT, menstruation restarted in 67% of those with menstrual disturbances versus 5% in placebo. In one observational study, 91% of patients no longer had signs or symptoms of galactorrhea. In the RCT, adverse drug reactions (ADRs) occurred at similar incidence rates among metformin and placebo patients, except that no significant increases in nausea, insomnia and agitation occurred which were not associated with discontinuations. Our systematic review indicated that adjunctive metformin significantly lowered prolactin level and relieved prolactin-related symptoms in patients with antipsychotic-induced hyperprolactinemia. Future higher quality RCTs need to verify the currently available limited evidence based on three trials which suggest that adjunctive metformin may be used effectively and safely for antipsychotic-induced hyperprolactinemia. PMID:26822064

  10. Metformin induces differentiation in acute promyelocytic leukemia by activating the MEK/ERK signaling pathway

    SciTech Connect

    Huai, Lei; Wang, Cuicui; Zhang, Cuiping; Li, Qihui; Chen, Yirui; Jia, Yujiao; Li, Yan; Xing, Haiyan; Tian, Zheng; Rao, Qing; Wang, Min; Wang, Jianxiang

    2012-06-08

    Highlights: Black-Right-Pointing-Pointer Metformin induces differentiation in NB4 and primary APL cells. Black-Right-Pointing-Pointer Metformin induces activation of the MEK/ERK signaling pathway in APL cells. Black-Right-Pointing-Pointer Metformin synergizes with ATRA to trigger maturation of NB4 and primary APL cells. Black-Right-Pointing-Pointer Metformin induces the relocalization and degradation of the PML-RAR{alpha} fusion protein. Black-Right-Pointing-Pointer The study may be applicable for new differentiation therapy in cancer treatment. -- Abstract: Recent studies have shown that metformin, a widely used antidiabetic agent, may reduce the risk of cancer development. In this study, we investigated the antitumoral effect of metformin on both acute myeloid leukemia (AML) and acute promyelocytic leukemia (APL) cells. Metformin induced apoptosis with partial differentiation in an APL cell line, NB4, but only displayed a proapoptotic effect on several non-M3 AML cell lines. Further analysis revealed that a strong synergistic effect existed between metformin and all-trans retinoic acid (ATRA) during APL cell maturation and that metformin induced the hyperphosphorylation of extracellular signal-regulated kinase (ERK) in APL cells. U0126, a specific MEK/ERK activation inhibitor, abrogated metformin-induced differentiation. Finally, we found that metformin induced the degradation of the oncoproteins PML-RAR{alpha} and c-Myc and activated caspase-3. In conclusion, these results suggest that metformin treatment may contribute to the enhancement of ATRA-induced differentiation in APL, which may deepen the understanding of APL maturation and thus provide insight for new therapy strategies.

  11. Unraveling the role of adenosine in remote ischemic preconditioning-induced cardioprotection.

    PubMed

    Randhawa, Puneet Kaur; Jaggi, Amteshwar Singh

    2016-06-15

    Remote ischemic preconditioning (RIPC) induced by alternate cycles of preconditioning ischemia and reperfusion protects the heart against sustained ischemia-reperfusion-induced injury. This technique has been translated to clinical levels in patients undergoing various surgical interventions including coronary artery bypass graft surgery, abdominal aortic aneurysm repair, percutaneous coronary intervention and heart valve surgery. Adenosine is a master regulator of energy metabolism and reduces myocardial ischemia-reperfusion-induced injury. Furthermore, adenosine is a critical trigger as well as a mediator in RIPC-induced cardioprotection and scientists have demonstrated the role of adenosine by showing an increase in its levels in the systemic circulation during RIPC delivery. Furthermore, the blockade of cardioprotective effects of RIPC in the presence of specific adenosine receptor blockers and transgenic animals with targeted ablation of A1 receptors has also demonstrated its critical role in RIPC. The studies have shown that adenosine may elicit cardioprotection via activation of neurogenic pathway. The present review describes the possible role and mechanism of adenosine in mediating RIPC-induced cardioprotection. PMID:27157518

  12. Mechanisms Involved in Exercise-Induced Cardioprotection: A Systematic Review

    PubMed Central

    Borges, Juliana Pereira; Lessa, Marcos Adriano

    2015-01-01

    Background Acute myocardial infarction is the leading cause of morbidity and mortality worldwide. Furthermore, research has shown that exercise, in addition to reducing cardiovascular risk factors, can also protect the heart against injury due to ischemia and reperfusion through a direct effect on the myocardium. However, the specific mechanism involved in exerciseinduced cardiac preconditioning is still under debate. Objective To perform a systematic review of the studies that have addressed the mechanisms by which aerobic exercise promotes direct cardioprotection against ischemia and reperfusion injury. Methods A search was conducted using MEDLINE, Literatura Latino-Americana e do Caribe de Informação em Ciências da Saúde, and Scientific Electronic Library Online databases. Data were extracted in a standardized manner by two independent researchers, who were responsible for assessing the methodological quality of the studies. Results The search retrieved 78 studies; after evaluating the abstracts, 30 studies were excluded. The manuscripts of the remaining 48 studies were completely read and, of these, 20 were excluded. Finally, 28 studies were included in this systematic review. Conclusion On the basis of the selected studies, the following are potentially involved in the cardioprotective response to exercise: increased heat shock protein production, nitric oxide pathway involvement, increased cardiac antioxidant capacity, improvement in ATP-dependent potassium channel function, and opioid system activation. Despite all the previous investigations, further research is still necessary to obtain more consistent conclusions. PMID:25830711

  13. Possible role of thromboxane A2 in remote hind limb preconditioning-induced cardioprotection.

    PubMed

    Sharma, Roohani; Randhawa, Puneet Kaur; Singh, Nirmal; Jaggi, Amteshwar Singh

    2016-01-01

    Remote hind limb preconditioning (RIPC) is a protective strategy in which short episodes of ischemia and reperfusion in a remote organ (hind limb) protects the target organ (heart) against sustained ischemic reperfusion injury. The present study was designed to investigate the possible role of thromboxane A2 in RIPC-induced cardioprotection in rats. Remote hind limb preconditioning was performed by four episodes of 5 min of inflation and 5 min of deflation of pressure cuff. Occlusion of the hind limb with blood pressure cuff is most feasible, non-invasive, clinically relevant, and safe method for inducing RIPC. Isolated rat hearts were perfused on Langendorff apparatus and were subjected to global ischemia for 30 min followed by 120-min reperfusion. The levels of lactate dehydrogenase (LDH) and creatine kinase (CK) were measured in coronary effluent to assess the degree of myocardial injury. The extent of myocardial infarct size along with the functional parameters including left ventricular developed pressure (LVDP), dp/dtmax, and dp/dtmin were also measured. Ozagrel (thromboxane synthase inhibitor) and seratrodast (thromboxane A2 receptor antagonist) were employed as pharmacological modulators of thromboxane A2. Remote hind limb preconditioning significantly attenuated ischemia/reperfusion-induced myocardial injury and produced cardioprotective effects. However, administration of ozagrel and seratrodast completely abolished the cardioprotective effects of RIPC suggesting the key role of thromboxane A2 in RIPC-induced cardioprotection. It may be concluded that brief episodes of preconditioning ischemia and reperfusion activates the thromboxane synthase enzyme that produces thromboxane A2, which may elicit cardioprotection either involving humoral or neurogenic pathway. PMID:26531833

  14. Linoleic acid attenuates cardioprotection induced by resolvin D1.

    PubMed

    Gilbert, Kim; Malick, Mandy; Madingou, Ness; Bourque-Riel, Valérie; Touchette, Charles; Rousseau, Guy

    2016-05-01

    We previously observed that resolvin D1 (RvD1), a metabolite of the omega-3 polyunsaturated fatty acid (PUFA) docosahexaenoic acid, reduces infarct size by a mechanism involving the PI3-K/Akt pathway. In parallel, the beneficial effect of a high omega-3 PUFA diet on infarct size can be attenuated by increased omega-6 PUFA consumption. The present study was designed to determine if augmented linoleic acid (LA), an omega-6 PUFA administered at the same time, attenuates the cardioprotective action of RvD1. Male Sprague-Dawley rats received 0.1μg RvD1 alone or with one of three LA doses (1, 5 or 10μg) directly into the left ventricle chamber 5min before ischemia. The animals underwent 40min of ischemia by occlusion of the left descending coronary artery followed by 30min or 24h of reperfusion. Infarct size and neutrophil accumulation were evaluated after 24h of reperfusion, while caspase-3, -8 and -9 and Akt activities were assessed at 30min of reperfusion. LA attenuated cardioprotection afforded by RvD1, resulting in significantly increased infarct size. Neutrophil accumulation and Akt activity were similar between groups. Caspase activities, especially caspase-9, which could be activated by ischemia, were stimulated in the presence of LA, suggesting that this omega-6 PUFA accentuates ischemia intensity. The present results indicate that LA significantly attenuates the beneficial effect of RvD1 on infarct size. Therefore, reduction of omega-6 intake should be considered to maintain the protection afforded by RvD1. PMID:27133431

  15. Lactic acidosis induced by metformin: incidence, management and prevention.

    PubMed

    Lalau, Jean-Daniel

    2010-09-01

    Lactic acidosis associated with metformin treatment is a rare but important adverse event, and unravelling the problem is critical. First, this potential event still influences treatment strategies in type 2 diabetes mellitus, particularly in the many patients at risk of kidney failure, in those presenting contraindications to metformin and in the elderly. Second, the relationship between metformin and lactic acidosis is complex, since use of the drug may be causal, co-responsible or coincidental. The present review is divided into three parts, dealing with the incidence, management and prevention of lactic acidosis occurring during metformin treatment. In terms of incidence, the objective of this article is to counter the conventional view of the link between metformin and lactic acidosis, according to which metformin-associated lactic acidosis is rare but is still associated with a high rate of mortality. In fact, the direct metformin-related mortality is close to zero and metformin may even be protective in cases of very severe lactic acidosis unrelated to the drug. Metformin has also inherited a negative class effect, since the early biguanide, phenformin, was associated with more frequent and sometimes fatal lactic acidosis. In the second part of this review, the objective is to identify the most efficient patient management methods based on our knowledge of how metformin acts on glucose/lactate metabolism and how lactic acidosis may occur (at the organ and cellular levels) during metformin treatment. The liver appears to be a key organ for both the antidiabetic effect of metformin and the development of lactic acidosis; the latter is attributed to mitochondrial impairment and subsequent adenosine triphosphate depletion, acceleration of the glycolytic flux, increased glucose uptake and the generation of lactate, which effluxes into the circulation rather than being oxidized further. Haemodialysis should systematically be performed in severe forms of lactic

  16. Investigations on the role of leukotrienes in remote hind limb preconditioning-induced cardioprotection in rats.

    PubMed

    Singh, Baljeet; Randhawa, Puneet Kaur; Singh, Nirmal; Jaggi, Amteshwar Singh

    2016-05-01

    The cardioprotective effects of remote hind limb preconditioning (RIPC) are well established, but its mechanisms still remain to be explored. Therefore, the present study was aimed to explore the possible involvement of 5-lipoxygenase-derived leukotrienes in RIPC. The hind limb was tied by a pressure cuff and was subjected to four episodes of inflation and deflation (5min each) to induce remote hind-limb preconditioning. Thereafter, the hearts were isolated and were subjected to global ischemia (30min) followed by reperfusion (120min) on the Langendorff apparatus. The extent of myocardial injury was assessed by measuring lactate dehydrogenase (LDH) and creatine kinase (CK) levels in the coronary effluent; the infarct size using TTC staining, and the hemodynamic parameters including LVDP, dp/dtmax and dp/dtmin. RIPC significantly decreased ischemia and reperfusion-induced increase in LDH, CK release, infarct size and improved LVDP, dp/dtmax and dp/dtmin. Administration of montelukast, leukotriene receptor antagonist (10 and 20mg/kg) and zileuton, 5-lipoxygenase inhibitor, (2.5 and 5mg/kg) abolished RIPC-induced cardioprotection. It may be concluded that hind limb ischemia stimulates 5-lipoxygenase to release leukotrienes which may elicit cardioprotection by humoral or neurogenic pathway. PMID:27058978

  17. Delayed auditory conduction in diabetes: is metformin-induced vitamin B12 deficiency responsible?

    PubMed Central

    Khattar, Deepti; Khaliq, Farah; Vaney, Neelam; Madhu, Sri Venkata

    2016-01-01

    Summary The present study aims to evaluate the functional integrity of the auditory pathway in patients with diabetes taking metformin. A further aim is to assess its association with vitamin B12 deficiency induced by metformin. Thirty diabetics taking metformin and 30 age-matched non-diabetic controls were enrolled. Stimulus-related potentials and vitamin B12 levels were evaluated in all the subjects. The diabetics showed deficient vitamin B12 levels and delayed wave III latency and III–V interpeak latency in the right ear and delayed Na and Pa wave latencies in the left ear compared with the controls. The dose and duration of metformin showed no association with the stimulus-related potentials. Therefore, although vitamin B12 levels were deficient and auditory conduction impairment was present in the diabetics on metformin, this impairment cannot be attributed to the vitamin B12 deficiency. PMID:27358222

  18. Metformin Prevented Dopaminergic Neurotoxicity Induced by 3,4-Methylenedioxymethamphetamine Administration.

    PubMed

    Porceddu, Pier Francesca; Ishola, Ismail Ogunbayode; Contu, Liliana; Morelli, Micaela

    2016-07-01

    Metformin, a well-known antidiabetic drug, has recently been proposed to promote neurogenesis and to have a neuroprotective effect on the neurodegenerative processes induced by the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in models of Parkinson's disease. Interestingly, metformin has antioxidant properties and is involved in regulating the production of cytokines released during the neuroinflammatory process. Several studies have reported that 3,4-methylenedioxymethamphetamine (MDMA), a recreational drug mostly consumed by young adults, produces a persistent loss of dopaminergic neurons in the substantia nigra pars compacta (SNc) and caudate putamen (CPu) of mice. The aim of this study was to investigate the potential neuroprotective effect of metformin against short- and long-term neurotoxicity induced by MDMA and its role on MDMA-induced hyperthermia. Adult mice received metformin (2 × 200 mg/kg, 11-h intervals, administered orally), MDMA (4 × 20 mg/kg, 2-h interval, administered intraperitoneally), or MDMA plus metformin (2 × 200 mg/kg, 1 h before the first MDMA administration and 4 h after the last). On the second and third day, mice were treated with vehicle or metformin (1 × 200 mg/kg) and sacrificed 48 h and 7 days after the last MDMA administration. The neuroprotective effect of metformin on MDMA-induced dopaminergic damage was evaluated by dopamine transporter (DAT) and tyrosine hydroxylase (TH) immunohistochemistry in SNc and CPu. Metformin prevented the MDMA-induced loss of TH-positive neurons in the SNc and TH- and DAT-positive fibers in CPu, both at 48 h and 7 days after the last MDMA administration. These results show that metformin is neuroprotective against the short- and long-lasting dopaminergic neurodegeneration induced by MDMA. PMID:27251371

  19. Metformin-Induced Fixed-Drug Eruption Confirmed by Multiple Exposures

    PubMed Central

    Steber, Carolyn J.; Perkins, Scott L.; Harris, Kira B.

    2016-01-01

    Patient: Female, 56 Final Diagnosis: Fixed-drug eruption Symptoms: — Medication: Metformin Clinical Procedure: Discontinued metformin Specialty: Family Medicine Objective: Unusual or unexpected effect of treatment Background: A fixed-drug eruption (FDE) is a reaction characterized by cutaneous lesions that appear due to exposure to a particular drug. Barbiturates, carbamazepine, sulfamethoxazole, and tetracyclines have all been associated with causation of FDEs. Although these drugs are more commonly associated with FDEs, any introduction of a medication has the potential to result in a FDE. Metformin, a commonly used medication to improve glycemic control, has been reported to cause dermatologic reactions in some case reports, but only a single previously documented case report discusses the potential of metformin-associated FDE. Case Report: We describe a 56-year-old woman who developed a FDE with multiple exposures to metformin. Upon each exposure, small, round, erythematic lesions developed on the palms of the hands and soles of the feet; these lesions resolved each time after discontinuation of metformin. According to the Naranjo scale, there is a definite association between metformin and FDE in this case (score of 8). Conclusions: This report contributes to the limited documented literature on metformin-induced FDE. Clinicians should be made aware of possible FDEs associated with this commonly used medication. PMID:27056044

  20. Cardioprotective Potential of Polyphenolic Rich Green Combination in Catecholamine Induced Myocardial Necrosis in Rabbits

    PubMed Central

    Zafar, Fatiqa; Jahan, Nazish; Khalil-Ur-Rahman; Khan, Ahrar; Akram, Waseem

    2015-01-01

    The present study was designed to develop safer, effective, and viable cardioprotective herbal combination to control oxidative stress related cardiac ailments as new alternatives to synthetic drugs. The synergetic cardioprotective potential of herbal combination of four plants T. arjuna (T.A.), P. nigrum (P.N), C. grandiflorus (C), and C. oxyacantha (Cr) was assessed through curative and preventive mode of treatment. In preventive mode of treatment, the cardiac injury was induced with synthetic catecholamine (salbutamol) to pretreated rabbits with the proposed herbal combination for three weeks. In curative mode of treatment, cardiotoxicity/oxidative stress was induced in rabbits with salbutamol prior to treating them with plant mixture. Cardiac marker enzymes, lipids profile, and antioxidant enzymes as biomarker of cardiotoxicity were determined in experimental animals. Rabbits administrated with mere salbutamol showed a significant increase in cardiac marker enzymes and lipid profile and decrease in antioxidant enzymes as compared to normal control indicating cardiotoxicity and myocardial cell necrosis. However, pre- and postadministration of plant mixture appreciably restored the levels of all biomarkers. Histopathological examination confirmed that the said combination was safer cardioprotective product. PMID:26379750

  1. Metformin Eased Cognitive Impairment Induced by Chronic L-methionine Administration: Potential Role of Oxidative Stress

    PubMed Central

    Alzoubi, Karem. H; Khabour, Omar. F; Al-azzam, Sayer I; Tashtoush, Murad H; Mhaidat, Nizar M

    2014-01-01

    Chronic administration of L-methionine leads to memory impairment, which is attributed to increase in the level of oxidative stress in the brain. On the other hand, metformin is a commonly used antidiabetic drug with strong antioxidant properties. In the current study, we tested if chronic metformin administration prevents memory impairment induced by administration of L-methionine. In addition, a number of molecules related to the action of metformin on cognitive functions were examined. Both metformin and L-methionine were administered to animals by oral gavage. Testing of spatial learning and memory was carried out using radial arm water maze (RAWM). Additionally, hippocampal levels or activities of catalase, thiobarbituric acid reactive substances (TBARs), glutathione peroxidase (GPx), glutathione (GSH), oxidized glutathione (GSSG) and GSH/GSSG ratio were determined. Results showed that chronic L-methionine administration resulted in both short- and long- term memory impairment, whereas metformin treatment prevented such effect. Additionally, L-methionine treatment induced significant elevation in GSSG and TBARs, along with reduction in GSH/GSSG ratio and activities of catalase, and GPx. These effects were shown to be restored by metformin treatment. In conclusion, L-methionine induced memory impairment, and treatment with metformin prevented this impairment probably by normalizing oxidative stress in the hippocampus. PMID:24669211

  2. Metformin and berberine prevent olanzapine-induced weight gain in rats.

    PubMed

    Hu, Yueshan; Young, Alan J; Ehli, Erik A; Nowotny, Dustin; Davies, Paige S; Droke, Elizabeth A; Soundy, Timothy J; Davies, Gareth E

    2014-01-01

    Olanzapine is a first line medication for the treatment of schizophrenia, but it is also one of the atypical antipsychotics carrying the highest risk of weight gain. Metformin was reported to produce significant attenuation of antipsychotic-induced weight gain in patients, while the study of preventing olanzapine-induced weight gain in an animal model is absent. Berberine, an herbal alkaloid, was shown in our previous studies to prevent fat accumulation in vitro and in vivo. Utilizing a well-replicated rat model of olanzapine-induced weight gain, here we demonstrated that two weeks of metformin or berberine treatment significantly prevented the olanzapine-induced weight gain and white fat accumulation. Neither metformin nor berberine treatment demonstrated a significant inhibition of olanzapine-increased food intake. But interestingly, a significant loss of brown adipose tissue caused by olanzapine treatment was prevented by the addition of metformin or berberine. Our gene expression analysis also demonstrated that the weight gain prevention efficacy of metformin or berberine treatment was associated with changes in the expression of multiple key genes controlling energy expenditure. This study not only demonstrates a significant preventive efficacy of metformin and berberine treatment on olanzapine-induced weight gain in rats, but also suggests a potential mechanism of action for preventing olanzapine-reduced energy expenditure. PMID:24667776

  3. Metformin and Berberine Prevent Olanzapine-Induced Weight Gain in Rats

    PubMed Central

    Hu, Yueshan; Young, Alan J.; Ehli, Erik A.; Nowotny, Dustin; Davies, Paige S.; Droke, Elizabeth A.; Soundy, Timothy J.; Davies, Gareth E.

    2014-01-01

    Olanzapine is a first line medication for the treatment of schizophrenia, but it is also one of the atypical antipsychotics carrying the highest risk of weight gain. Metformin was reported to produce significant attenuation of antipsychotic-induced weight gain in patients, while the study of preventing olanzapine-induced weight gain in an animal model is absent. Berberine, an herbal alkaloid, was shown in our previous studies to prevent fat accumulation in vitro and in vivo. Utilizing a well-replicated rat model of olanzapine-induced weight gain, here we demonstrated that two weeks of metformin or berberine treatment significantly prevented the olanzapine-induced weight gain and white fat accumulation. Neither metformin nor berberine treatment demonstrated a significant inhibition of olanzapine-increased food intake. But interestingly, a significant loss of brown adipose tissue caused by olanzapine treatment was prevented by the addition of metformin or berberine. Our gene expression analysis also demonstrated that the weight gain prevention efficacy of metformin or berberine treatment was associated with changes in the expression of multiple key genes controlling energy expenditure. This study not only demonstrates a significant preventive efficacy of metformin and berberine treatment on olanzapine-induced weight gain in rats, but also suggests a potential mechanism of action for preventing olanzapine-reduced energy expenditure. PMID:24667776

  4. Cardioprotective effect of royal jelly on paclitaxel-induced cardio-toxicity in rats

    PubMed Central

    Malekinejad, Hassan; Ahsan, Sima; Delkhosh-Kasmaie, Fatemeh; Cheraghi, Hadi; Rezaei-Golmisheh, Ali; Janbaz-Acyabar, Hamed

    2016-01-01

    Objective(s): Paclitaxel is a potent chemotherapy agent with severe side effects, including allergic reactions, cardiovascular problems, complete hair loss, joint and muscle pain, which may limit its use and lower its efficiency. The cardioprotective effect of royal jelly was investigated on paclitaxel-induced damages. Materials and Methods: Adult male Wistar rats were divided into control and test groups (n=8). The test group was assigned into five subgroups; 4 groups, along with paclitaxel administration (7.5 mg/kg BW, weekly), received various doses of royal jelly (50, 100, and 150 mg/kg BW) for 28 consecutive days. The last group received only royal jelly at 100 mg/kg. In addition to oxidative and nitrosative stress biomarkers, the creatine kinase (CK-BM) level was also determined. To show the cardioprotective effect of royal jelly on paclitaxel-induced damages, histopathological examinations were conducted. Results: Royal jelly lowered the paclitaxel-elevated malondialdehyde and nitric oxide levels in the heart. Royal jelly could also remarkably reduce the paclitaxel-induced cardiac biomarker of creatine kinase (CK-BM) level and pathological injuries such as diffused edema, hemorrhage, congestion, hyaline exudates, and necrosis. Moreover, royal jelly administration in a dose-dependent manner resulted in a significant (P<0.05) increase in the paclitaxel-reduced total antioxidant capacity. Conclusion: Our data suggest that the paclitaxel-induced histopathological and biochemical alterations could be protected by the royal jelly administration. The cardioprotective effect of royal jelly may be related to the suppression of oxidative and nitrosative stress. PMID:27081469

  5. Ω3 Supplementation and Intermittent Hypobaric Hypoxia Induce Cardioprotection Enhancing Antioxidant Mechanisms in Adult Rats

    PubMed Central

    Herrera, Emilio A.; Farías, Jorge G.; González-Candia, Alejandro; Short, Stefania E.; Carrasco-Pozo, Catalina; Castillo, Rodrigo L.

    2015-01-01

    Intermittent hypobaric hypoxia (IH) is linked with oxidative stress, impairing cardiac function. However, early IH also activate cardio-protective mechanisms. Omega 3 fatty acids (Ω3) induce cardioprotection by reducing infarct size and reinforcing antioxidant defenses. The aim of this work was to determine the combined effects of IH and Ω3 on cardiac function; oxidative balance and inflammatory state. Twenty-eight rats were randomly divided into four groups: normobaric normoxia (N); N + Ω3 (0.3 g·kg−1·day−1); IH; and IH + Ω3. IH was induced by 4 intercalate periods of hypoxia (4 days)—normoxia (4 days) in a hypobaric chamber during 32 days. At the end of the exposure, hearts were mounted in a Langendorff system and subjected to 30 min of ischemia followed by 120 min of reperfusion. In addition, we determined HIF-1α and ATP levels, as well as oxidative stress by malondialdehyde and nitrotyrosine quantification. Further, the expression of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase was determined. NF-kappaB and myeloperoxidase levels were assessed in the hearts. Relative to N hearts, IH improved left ventricular function (Left ventricular developed pressure: N; 21.8 ± 3.4 vs. IH; 42.8 ± 7.1 mmHg; p < 0.05); reduced oxidative stress (Malondialdehyde: N; 14.4 ± 1.8 vs. IH; 7.3 ± 2.1 μmol/mg prot.; p < 0.05); and increased antioxidant enzymes expression. Supplementation with Ω3 induces similar responses as IH group. Our findings suggest that both, IH and Ω3 in an independent manner, induce functional improvement by antioxidant and anti-inflammatory mechanisms, establishing cardio-protection. PMID:25658050

  6. Gadolinium and ruthenium red attenuate remote hind limb preconditioning-induced cardioprotection: possible role of TRP and especially TRPV channels.

    PubMed

    Randhawa, Puneet Kaur; Jaggi, Amteshwar Singh

    2016-08-01

    Remote ischemic preconditioning is a well reported therapeutic strategy that induces cardioprotective effects but the underlying intracellular mechanisms have not been widely explored. The current study was designed to investigate the involvement of TRP and especially TRPV channels in remote hind limb preconditioning-induced cardioprotection. Remote hind limb preconditioning stimulus (4 alternate cycles of inflation and deflation of 5 min each) was delivered using a blood pressure cuff tied on the hind limb of the anesthetized rat. Using Langendorff's system, the heart was perfused and subjected to 30-min ischemia and 120-min reperfusion. The myocardial injury was assessed by measuring infarct size, lactate dehydrogenase (LDH), creatine kinase (CK), LVDP, +dp/dtmax, -dp/dtmin, heart rate, and coronary flow rate. Gadolinium, TRP blocker, and ruthenium red, TRPV channel blocker, were employed as pharmacological tools. Remote hind limb preconditioning significantly reduced the infarct size, LDH release, CK release and improved coronary flow rate, hemodynamic parameters including LVDP, +dp/dtmax, -dp/dtmin, and heart rate. However, gadolinium (7.5 and 15 mg kg(-1)) and ruthenium red (4 and 8 mg kg(-1)) significantly attenuated the cardioprotective effects suggesting the involvement of TRP especially TRPV channels in mediating remote hind limb preconditioning-induced cardioprotection. Remote hind limb preconditioning stimulus possibly activates TRPV channels on the heart or sensory nerve fibers innervating the heart to induce cardioprotective effects. Alternatively, remote hind limb preconditioning stimulus may also activate the mechanosensitive TRP and especially TRPV channels on the sensory nerve fibers innervating the skeletal muscles to trigger cardioprotective neurogenic signaling cascade. The cardioprotective effects of remote hind limb preconditioning may be mediated via activation of mechanosensitive TRP and especially TRPV channels. PMID:27118661

  7. Is Metformin-Induced Vitamin B12 Deficiency Responsible for Cognitive Decline in Type 2 Diabetes?

    PubMed Central

    Khattar, Deepti; Khaliq, Farah; Vaney, Neelam; Madhu, S. V.

    2016-01-01

    Introduction: Diabetes mellitus has its deleterious effects on various aspects of cognition such as memory function, executive function, and information-processing speed. The present study aims to assess cognition in diabetes patients and also tries to find its association with Vitamin B12 deficiency induced by metformin. Materials and Methods: Thirty diabetics taking metformin and thirty nondiabetic controls were enrolled. Event-related potentials (ERPs) and serum Vitamin B12 levels were evaluated in them. Results: Vitamin B12 levels were found to be deficient, and latencies of waves P200 and P300 were prolonged in the diabetics as compared to the controls. The dose and duration of metformin had no association with the ERPs. Conclusions: Although the Vitamin B12 levels were deficient in diabetics on metformin, this is not the reason behind the cognitive impairment found in them. PMID:27570337

  8. Metformin as a Rare Cause of Drug-Induced Liver Injury, a Case Report and Literature Review.

    PubMed

    Zheng, Lin

    2016-01-01

    Metformin is an oral hypoglycemic agent that is commonly used in the treatment of type 2 diabetes mellitus. Although metformin-associated gastrointestinal upset and metabolic acidosis is widely recognized side effect of this drug, metformin-induced liver injury has been rarely reported in the literature. In most cases reported, metformin-induced liver injury was associated with concomitant intake of other hepatotoxic drugs. Here, we report a case of a 70-year-old white woman who suffered metformin-induced liver injury 5 weeks after starting on this medication, and she was not on any other hepatotoxic agent. With increasing prescription of metformin, this case deserves particular attention for this rare but important side effect. PMID:24263160

  9. Metformin induces a Senescence-associated gene Signature in Breast Cancer Cells

    PubMed Central

    Williams, Christopher C.; Singleton, Brittany A.; Llopis, Shawn D.; Skripnikova, Elena V.

    2013-01-01

    Diabetic patients taking metformin have lower incidence of breast cancer than those taking other anti-diabetic medications. Additionally, triple negative breast cancer (TNBC), a form of breast cancer disproportionately afflicting premenopausal African American women, shows atypical susceptibility to metformin’s antiproliferative effect. The mechanisms involved in metformin’s function in TNBC has not yet been fully elucidated. Therefore, we sought to identify pathways regulated by metformin in using the MDA-MB-468 TNBC cell model. Metformin dose-dependently caused apoptosis, decreased cell viability, and induced cell morphology/chromatin condensation consistent with the permanent proliferative arrest. Furthermore, gene expression arrays revealed that metformin caused expression of stress markers DDIT3, CYP1A1, and GDF-15 and a concomitant reduction in PTGS1 expression. Our findings show that metformin may affect the viability and proliferative capacity of TNBC by inducing an antiproliferative gene signature, and that metformin may be effective in the treatment/prevention of TNBC. PMID:23395946

  10. Metformin-induced inhibition of the mitochondrial respiratory chain increases FGF21 expression via ATF4 activation

    SciTech Connect

    Kim, Kook Hwan; Jeong, Yeon Taek; Kim, Seong Hun; Jung, Hye Seung; Park, Kyong Soo; Lee, Hae-Youn; Lee, Myung-Shik

    2013-10-11

    Highlights: •Metformin induces FGF21 expression in an AMPK independent manner. •Metformin enhances FGF21 expression by inhibiting mitochondrial complex I activity. •The PERK-eIF2α-ATF4 axis is required for metformin-induced FGF21 expression. •Metformin activates the ATF4-FGF21 axis in the liver of mouse. •Metformin increases serum FGF21 level in diabetic human subjects. -- Abstract: Fibroblast growth factor 21 (FGF21) is an endocrine hormone that exhibits anti-obesity and anti-diabetes effects. Because metformin is widely used as a glucose-lowering agent in patients with type 2 diabetes (T2D), we investigated whether metformin modulates FGF21 expression in cell lines, and in mice or human subjects. We found that metformin increased the expression and release of FGF21 in a diverse set of cell types, including rat hepatoma FaO, primary mouse hepatocytes, and mouse embryonic fibroblasts (MEFs). Intriguingly, AMP-activated protein kinase (AMPK) was dispensable for the induction of FGF21 by metformin. Mammalian target of rapamycin complex 1 (mTORC1) and peroxisome proliferator-activated receptor α (PPARα), which are additional targets of metformin, were not involved in metformin-induced FGF21 expression. Importantly, inhibition of mitochondrial complex I activity by metformin resulted in FGF21 induction through PKR-like ER kinase (PERK)-eukaryotic translation factor 2α (eIF2α)-activating transcription factor 4 (ATF4). We showed that metformin activated ATF4 and increased FGF21 expression in the livers of mice, which led to increased serum levels of FGF21. We also found that serum FGF21 level was increased in human subjects with T2D after metformin therapy for 6 months. In conclusion, our results indicate that metformin induced expression of FGF21 through an ATF4-dependent mechanism by inhibiting mitochondrial respiration independently of AMPK. Therefore, FGF21 induction by metformin might explain a portion of the beneficial metabolic effects of metformin.

  11. Metformin-induced lactic acidosis: a case series

    PubMed Central

    Silvestre, Joana; Carvalho, Susana; Mendes, Vitor; Coelho, Luis; Tapadinhas, Camila; Ferreira, Pedro; Povoa, Pedro; Ceia, Fatima

    2007-01-01

    Introduction Unlike other agents used in the treatment of type 2 diabetes mellitus, metformin has been shown to reduce mortality in obese patients. It is therefore being increasingly used in higher doses. The major concern of many physicians is a possible risk of lactic acidosis. The reported frequency of metformin related lactic acidosis is 0.05 per 1000 patient-years; some authors advocate that this rate is equal in those patients not taking metformin. Case presentation We present two case reports of metformin-associated lactic acidosis. The first case is a 77 year old female with a past medical history of hypertension and type 2 diabetes mellitus who had recently been prescribed metformin (3 g/day), perindopril and acetylsalicylic acid. She was admitted to the emergency department two weeks later with abdominal pain and psychomotor agitation. Physical examination revealed only signs of poor perfusion. Laboratory evaluation revealed hyperkalemia, elevated creatinine and blood urea nitrogen and mild leukocytosis. Arterial blood gases showed severe lactic acidemia. She was admitted to the intensive care unit. Vasopressor and ventilatory support was initiated and continuous venovenous hemodiafiltration was instituted. Twenty-four hours later, full clinical recovery was observed, with return to a normal serum lactate level. The patient was discharged from the intensive care unit on the sixth day. The second patient is a 69 year old male with a past medical history of hypertension, type 2 diabetes mellitus and ischemic heart disease who was on metformin (4 g/day), glycazide, acetylsalicylic acid and isosorbide dinitrate. He was admitted to the emergency department in shock with extreme bradycardia. Initial evaluation revealed severe lactic acidosis and elevated creatinine and urea. The patient was admitted to the Intensive Care Unit and commenced on continuous venovenous hemodiafiltration in addition to other supportive measures. A progressive recovery was observed

  12. Metformin Prevents Cisplatin-Induced Cognitive Impairment and Brain Damage in Mice

    PubMed Central

    Zhou, Wenjun; Kavelaars, Annemieke; Heijnen, Cobi J.

    2016-01-01

    Rationale Chemotherapy-induced cognitive impairment, also known as ‘chemobrain’, is now widely recognized as a frequent adverse side effect of cancer treatment that often persists into survivorship. There are no drugs available to prevent or treat chemotherapy-induced cognitive deficits. The aim of this study was to establish a mouse model of cisplatin-induced cognitive deficits and to determine the potential preventive effects of the anti-diabetic drug metformin. Results Treatment of C57/BL6J mice with cisplatin (cumulative dose 34.5mg/kg) impaired performance in the novel object and place recognition task as well as in the social discrimination task indicating cognitive deficits. Co-administration of metformin prevented these cisplatin-induced cognitive impairments. At the structural level, we demonstrate that cisplatin reduces coherency of white matter fibers in the cingulate cortex. Moreover, the number of dendritic spines and neuronal arborizations as quantified on Golgi-stained brains was reduced after cisplatin treatment. Co-administration of metformin prevented all of these structural abnormalities in cisplatin-treated mice. In contrast to what has been reported in other models of chemobrain, we do not have evidence for persistent microglial or astrocyte activation in the brains of cisplatin-treated mice. Finally, we show that co-administration of metformin also protects against cisplatin-induced peripheral neuropathy. Conclusion In summary, we show here for the first time that treatment of mice with cisplatin induces cognitive deficits that are associated with structural abnormalities in the brain. Moreover, we present the first evidence that the widely used and safe anti-diabetic drug metformin protects against these deleterious effects of cancer treatment. In view of the ongoing clinical trials to examine the potential efficacy of metformin as add-on therapy in patients treated for cancer, these findings should allow rapid clinical translation. PMID

  13. Metformin ameliorates ovariectomy-induced vascular dysfunction in non-diabetic Wistar rats.

    PubMed

    Oliveira, Phablo Wendell C; de Sousa, Glauciene J; Caliman, Izabela F; Lamas, Aline Z; Santos de Medeiros, Ana Raquel; de Andrade, Tadeu U; de Abreu, Glaucia R; de Figueiredo, Suely G; Bissoli, Nazaré S

    2014-08-01

    Metformin is an antihyperglycaemic drug with pleiotropic effects that result in cardiovascular improvement. The aim of the present study was to evaluate the effects of metformin treatment on vascular dysfunction in ovariectomized rats. At 8 weeks of age, female Wistar rats were subjected to ovariectomy or a sham surgery. After 21 days, the animals were divided into three groups: SHAM (sham-operated rats), OVX (ovariectomized rats) and MET (ovariectomized rats treated with metformin at 300 mg/kg of body weight per day), and treated for 14 days. The vasorelaxation responses to ACh (acetylcholine) and SNP (sodium nitroprusside) were evaluated in mesenteric vascular beds, oxidative stress was evaluated and Western blot analysis of eNOS (endothelial NO synthase) and the NADPH oxidase Nox2 was performed. ACh-induced relaxation was reduced in the OVX group and partially restored in the MET group. L-NAME (NG-nitro-L-arginine methyl ester) attenuated and equalized the ACh-induced response in all groups. Attenuation of the ACh-induced responses by 4-aminopyridine (a blocker of voltage-gated potassium channels) was greater in the MET group compared with the OVX group. The SNP-induced responses were reduced in the OVX group and restored in the MET group. Inhibition of NADPH oxidase by apocynin (10 μM) restored the SNP-induced responses in the OVX group, enhanced these responses in the MET group and had no effect in the SHAM group. The OVX group exhibited reduced levels of eNOS protein and increased levels of oxidative stress and Nox2 protein; metformin treatment corrected all of these parameters. In conclusion, the pathophysiological changes observed in the mesenteric beds of ovariectomized rats were ameliorated by metformin. If this translates to humans, metformin could have additional benefits for post-menopausal women treated with this drug for glycaemic control. PMID:24521306

  14. Impaired Oocyte Quality Induced by Dehydroepiandrosterone Is Partially Rescued by Metformin Treatment

    PubMed Central

    Huang, Ying; Yu, Yang; Gao, Jiangman; Li, Rong; Zhang, Chunmei; Zhao, Hongcui; Zhao, Yue; Qiao, Jie

    2015-01-01

    The present study evaluated the influence of hyperandrogenism on oocyte quality using a murine PCOS model induced by dehydroepiandrosterone (DHEA) and further explored the effect of metformin treatment. Female BALB/c mice were treated with a vehicle control or DHEA (6 mg /100 g body weight) or DHEA plus metformin (50 mg /100 g body weight) for 20 consecutive days. DHEA-induced mice resembled some characters of human PCOS, such as irregular sexual cycles and polycystic ovaries. After the model validation was completed, metaphase II (MII) oocytes were retrieved and subsequent analyses of oocyte quality were performed. DHEA-treated mice yielded fewer MII oocytes, which displayed decreased mtDNA copy number, ATP content, inner mitochondrial membrane potential, excessive oxidative stress and impaired embryo development competence compared with those in control mice. Metformin treatment partially attenuated those damages, as evidenced by the increased fertilization and blastocyst rate, ATP content, GSH concentration and GSH/GSSG ratio, and decreased reactive oxygen species levels. No significant difference in normal spindle assembly was observed among the three groups. During in vitro maturation (IVM), the periods of germinal vesicle breakdown (GVBD) and the first polar body (PB1) extrusion were extended and the maturation rate of GVBD oocytes was decreased in DHEA mice compared with controls. Metformin treatment decreased the time elapsed of GVBD while had no effect on PB1 extrusion. These results indicated that excessive androgen is detrimental to oocyte quality while metformin treatment is, directly or indirectly, beneficial for oocyte quality improvement. PMID:25811995

  15. p53 is required for metformin-induced growth inhibition, senescence and apoptosis in breast cancer cells.

    PubMed

    Li, Puyu; Zhao, Ming; Parris, Amanda B; Feng, Xiaoshan; Yang, Xiaohe

    2015-09-01

    The p53 tumor repressor gene is commonly mutated in human cancers. The tumor inhibitory effect of metformin on p53-mutated breast cancer cells remains unclear. Data from the present study demonstrated that p53 knockdown or mutation has a negative effect on metformin or phenformin-induced growth inhibition, senescence and apoptosis in breast cancer cells. We also found that p53 reactivating agent nutlin-3α and CP/31398 promoted metformin-induced growth inhibition, senescence and apoptosis in MCF-7 (wt p53) and MDA-MB-231 (mt p53) cells, respectively. Treatment of MCF-7 cells with metformin or phenformin induced increase in p53 protein levels and the transcription of its downstream target genes, Bax and p21, in a dose-dependent manner. Moreover, we demonstrated that AMPK-mTOR signaling played a role in metformin-induced p53 up-regulation. The present study showed that p53 is required for metformin or phenformin-induced growth inhibition, senescence and apoptosis in breast cancer cells. The combination of metformin with p53 reactivating agents, like nutlin-3α and CP/31398, is a promising strategy for improving metformin-mediated anti-cancer therapy, especially for tumors with p53 mutations. PMID:26225749

  16. Bio-enhancing Effect of Piperine with Metformin on Lowering Blood Glucose Level in Alloxan Induced Diabetic Mice

    PubMed Central

    Atal, Shubham; Atal, Sarjana; Vyas, Savita; Phadnis, Pradeep

    2016-01-01

    Background: Diabetes mellitus is the most rampant metabolic pandemic of the 21st century. Piperine, the chief alkaloid of Piper nigrum (black pepper) is widely used in alternative and complementary therapies has been extensively studied for its bio-enhancing property. Objective: To evaluate the bio-enhancing effect of piperine with metformin in lowering blood glucose levels in alloxan-induced diabetic mice. Materials and Methods: Piperine was isolated from an extract of fruits of P. nigrum. Alloxan-induced (150 mg/kg intraperitoneal) diabetic mice were divided into four groups. Group I (control 2% gum acacia 2 g/100 mL), Group II (metformin 250 mg/kg), Group III (metformin and piperine 250 mg/kg + 10 mg/kg), and Group IV (metformin and piperine 125 mg/kg + 10 mg/kg). All the drugs were administered orally once daily for 28 days. Blood glucose levels were estimated at day 0, day 14, and end of the study (day 28). Results: The combination of piperine with therapeutic dose of metformin (10 mg/kg + 250 mg/kg) showed significantly more lowering of blood glucose level as compared to metformin alone on both 14th and 28th day (P < 0.05). Piperine in combination with sub-therapeutic dose of metformin (10 mg/kg + 125 mg/kg) showed significantly more lowering of blood glucose as compared to control group and also showed greater lowering of blood glucose as compared to metformin (250 mg/kg) alone. Conclusion: Piperine has the potential to be used as a bio-enhancing agent in combination with metformin which can help reduce the dose of metformin and its adverse effects. SUMMARY Piperine is known for its bioenhancing property. This study evaluates the effect of piperine in combination with oral antidiabetic drug metformin. Drugs were administered for 28 days in alloxan induced diabetic mice and blood glucose lowering effect was seen. Results showed significantly better effect of combination of piperine with therapeutic dose of metformin in comparison to metformin alone. Piperine

  17. Honey and metformin ameliorated diabetes-induced damages in testes of rat; correlation with hormonal changes

    PubMed Central

    Nasrolahi, Ozra; Khaneshi, Fereshteh; Rahmani, Fatemeh; Razi, Mazdak

    2013-01-01

    Background: The global prevalence of diabetes mellitus is on rise. Diabetes-induced oxidative stress has been known to affect liver, pancreas, kidney and reproductive organs pathologically. Honey is a natural product of bee with antioxidant properties. Objective: Current study aimed to analyze the protective effects of Metformin (MF) alone and MF+ natural honey co-administration on diabetes-induced histological derangements in testis of rats. Materials and Methods: Thirty six, mature male Wistar rats were randomly divided into six groups including; control, honey-dosed non-diabetic, diabetes-induced (65 mg/kg, single dose), honey-administrated diabetic (1.0 g/kg/day), Metformin-received diabetic (100 mg/kg/day), Metformin and honey-co-treated diabetic which were followed 40 days. The animals were anesthetized by diethyl ether and the blood samples were collected. The serum levels of testosterone, Insulin, LH and FSH analyzed using antibody enzyme immunoassay method. The testicular tissues were dissected out and underwent to histological analyses. Results: The biochemical analyses revealed that the diabetes resulted in significantly reduced testosterone (p<0.01), LH and FSH (P<0.01, 0.001) levels in serum. Light microscopic analyses showed remarkable (p<0.01) reduction in seminiferous tubules diameter (STD), spermiogenesis index (SPI) and thickness of the epithelium in the diabetic group versus control and co-treated groups. Simultaneous administration of the honey with MF could fairly up-regulate testosterone, LH and FSH levels. The animals in metformin and honey-treated group exhibited with improved tubules atrophy, elevated spermiogenesis index and germinal epithelium thickness. Conclusion: Our data indicated that co-administration of Metformin and honey could inhibit the diabetes-induced damages in testicular tissue. Moreover, the simultaneous administration of metformin and honey up-regulated the diabetes-reduced insulin, LH, FSH and testosterone levels. This

  18. Nicorandil ameliorates mitochondrial dysfunction in doxorubicin-induced heart failure in rats: possible mechanism of cardioprotection.

    PubMed

    Ahmed, Lamiaa A; El-Maraghy, Shohda A

    2013-11-01

    Despite of its known cardiotoxicity, doxorubicin is still a highly effective anti-neoplastic agent in the treatment of several cancers. In the present study, the cardioprotective effect of nicorandil was investigated on hemodynamic alterations and mitochondrial dysfunction induced by cumulative administration of doxorubicin in rats. Doxorubicin was injected i.p. over 2 weeks to obtain a cumulative dose of 18 mg/kg. Nicorandil (3 mg/kg/day) was given orally with or without doxorubicin treatment. Heart rate and aortic blood flow were recorded 24 h after receiving the last dose of doxorubicin. Rats were then sacrificed and hearts were rapidly excised for estimation of caspase-3 activity, phosphocreatine and adenine nucleotides contents in addition to cytochrome c, Bcl2, Bax and caspase 3 expression. Moreover, mitochondrial oxidative phosphorylation capacity, creatine kinase activity and oxidative stress markers were measured together with the examination of DNA fragmentation and ultrastructural changes. Nicorandil was effective in alleviating the decrement of heart rate and aortic blood flow and the state of mitochondrial oxidative stress induced by doxorubicin cardiotoxicity. Nicorandil also preserved phosphocreatine and adenine nucleotides contents by restoring mitochondrial oxidative phosphorylation capacity and creatine kinase activity. Moreover, nicorandil provided a significant cardioprotection via inhibition of apoptotic signaling pathway, DNA fragmentation and mitochondrial ultrastructural changes. Interestingly, nicorandil did not interfere with cytotoxic effect of doxorubicin against the growth of solid Ehrlich carcinoma. In conclusion, nicorandil was effective against the development of doxorubicin-induced heart failure in rats as indicated by improvement of hemodynamic perturbations, mitochondrial dysfunction and ultrastructural changes without affecting its antitumor activity. PMID:23872193

  19. Metformin Protects Against Cisplatin-Induced Tubular Cell Apoptosis and Acute Kidney Injury via AMPKα-regulated Autophagy Induction

    PubMed Central

    Li, Jianzhong; Gui, Yuan; Ren, Jiafa; Liu, Xin; Feng, Ye; Zeng, Zhifeng; He, Weichun; Yang, Junwei; Dai, Chunsun

    2016-01-01

    Metformin, one of the most common prescriptions for patients with type 2 diabetes, is reported to protect the kidney from gentamicin-induced nephrotoxicity. However, the role and mechanisms for metformin in preventing cisplatin-induced nephrotoxicity remains largely unknown. In this study, a single intraperitoneal injection of cisplatin was employed to induce acute kidney injury (AKI) in CD1 mice. The mice exhibited severe kidney dysfunction and histological damage at day 2 after cisplatin injection. Pretreatment of metformin could markedly attenuate cisplatin-induced acute kidney injury, tubular cell apoptosis and inflammatory cell accumulation in the kidneys. Additionally, pretreatment of metformin could enhance both AMPKα phosphorylation and autophagy induction in the kidneys after cisplatin injection. In cultured NRK-52E cells, a rat kidney tubular cell line, metformin could stimulate AMPKα phosphorylation, induce autophagy and inhibit cisplatin-induced cell apoptosis. Blockade of either AMPKα activation or autophagy induction could largely abolish the protective effect of metformin in cisplatin-induced cell death. Together, this study demonstrated that metformin may protect against cisplatin-induced tubular cell apoptosis and AKI through stimulating AMPKα activation and autophagy induction in the tubular cells. PMID:27052588

  20. Neuro, cardio, and reno protective activities of rosuvastatin in streptozotocin-induced type 2 diabetic rats undergoing treatment with metformin and glimepiride

    PubMed Central

    Rondi, Shailaja; Peddolla, Ramu; Venisetty, Raj Kumar

    2014-01-01

    Diabetes is associated with complications like neuropathy, nephropathy, cardiomyopathy, and retinopathy due to increased oxidative stress and serum lipids. In the present study, rosuvastatin, a HMG-CoA inhibitor, was investigated for its protective effect in neuropathy, nephropathy, and cardiomyopathy based on the lipid-lowering property along with its pleiotropic effects such as improved blood flow to the organ and antioxidant defense. Type 2 diabetes was induced in Wistar rats by single i.p. administration of streptozotocin (50 mg/kg). These diabetic rats were treated with daily doses of rosuvastatin (10 mg/kg) alone, metformin (120 mg/kg) and glimepiride (1 mg/kg) and rosuvastatin in combination with metformin (120 mg/kg) and glimepiride (1 mg/kg) for a period of 6 weeks. The biochemical parameters involved in neuropathy, renopathy, and cardiopathy were estimated. Treatment resulted in significant (P < 0.05) decrease in thiobarbituric acid reactive substances (TBARS) and increase in levels of glutathione peroxidise and catalase in brain and kidney homogenates. Significant (P < 0.05) increase in high-density lipoproteins and decrease in creatinine kinase, triglycerides, total serum cholesterol represents the cardioprotective action, whereas significant (P < 0.05) increase in the latency in the hotplate model shows the neuroprotective activity, and significant (P < 0.05) decrease in blood urea nitrogen, creatinine levels and increase in serum total protein levels suggested the renoprotective actions. The unique properties of rosuvastatin such as antioxidant defense and lipid-lowering nature might have resulted in cardio, neuro, and renoprotective activity in type 2 diabetic rats treated with metformin and glimepiride. PMID:24959416

  1. Metformin Alleviated Aβ-Induced Apoptosis via the Suppression of JNK MAPK Signaling Pathway in Cultured Hippocampal Neurons

    PubMed Central

    Chen, Bin; Teng, Ying; Zhang, Xingguang; Lv, Xiaofeng

    2016-01-01

    Both diabetes and hyperinsulinemia are confirmed risk factors for Alzheimer's disease. Some researchers proposed that antidiabetic drugs may be used as disease-modifying therapies, such as metformin and thiazolidinediones, although more evidence was poorly supported. The aim of the current study is to investigate the role of metformin in Aβ-induced cytotoxicity and explore the underlying mechanisms. First, the experimental results show that metformin salvaged the neurons exposed to Aβ in a concentration-dependent manner with MTT and LDH assay. Further, the phosphorylation levels of JNK, ERK1/2, and p38 MAPK were measured with western blot analysis. It was investigated that Aβ increased phospho-JNK significantly but had no effect on phospho-p38 MAPK and phospho-ERK1/2. Metformin decreased hyperphosphorylated JNK induced by Aβ; however, the protection of metformin against Aβ was blocked when anisomycin, the activator of JNK, was added to the medium, indicating that metformin performed its protection against Aβ in a JNK-dependent way. In addition, it was observed that metformin protected the neurons via the suppression of apoptosis. Taken together, our findings demonstrate that metformin may have a positive effect on Aβ-induced cytotoxicity, which provides a preclinical strategy against AD for elders with diabetes. PMID:27403417

  2. Metformin Attenuates Testosterone-Induced Prostatic Hyperplasia in Rats: A Pharmacological Perspective

    PubMed Central

    Mosli, Hala H.; Esmat, Ahmed; Atawia, Reem T.; Shoieb, Sherif M.; Mosli, Hisham A.; Abdel-Naim, Ashraf B.

    2015-01-01

    Benign prostatic hyperplasia (BPH) is uncontrolled proliferation of prostate tissue. Metformin, a widely prescribed anti-diabetic agent, possesses anticancer activity through induction of apoptotic signaling and cell cycle arrest. This study aimed to investigate the protective effect of metformin against experimentally-induced BPH in rats. Treatment with 500 and 1000 mg/kg metformin orally for 14 days significantly inhibited testosterone-mediated increase in the prostate weight & prostate index (prostate weight/body weight [mg/g]) and attenuated the pathological alterations induced by testosterone. Mechanistically, metformin significantly protected against testosterone-induced elevation of estrogen receptor-α (ER-α) and decrease of estrogen receptor-β (ER-β) expression, with no significant effect of androgen receptor (AR) and 5α-reductase expression. It decreased mRNA expression of IGF-1 and IGF-1R and protein expression ratio of pAkt/total Akt induced by testosterone. Furthermore, it significantly ameliorated testosterone–induced reduction of mRNA expression Bax/Bcl-2 ratio, P21 and phosphatase and tensin homolog (PTEN) and AMPK [PT-172] activity. In conclusion, these findings elucidate the effectiveness of metformin in preventing testosterone-induced BPH in rats. These results could be attributed, at least partly, to its ability to enhance expression ratio of ER-β/ER-α, decrease IGF-1, IGF-1R and pAkt expressions, increase P21, PTEN, Bax/Bcl-2 expressions and activate AMPK with a subsequent inhibition of prostate proliferation. PMID:26492952

  3. Metformin Inhibits the IL-6-Induced Epithelial-Mesenchymal Transition and Lung Adenocarcinoma Growth and Metastasis

    PubMed Central

    Wang, Yubo; Han, Rui; Li, Li; Xiang, Tong; He, Luhang; Long, Haixia; Zhu, Bo; He, Yong

    2014-01-01

    Objective Epithelial-mesenchymal transition (EMT) plays an important role in cancer tumorigenesis. However, the underlying mechanisms of EMT in lung adenocarcinoma, and how this process might be inhibited, remain to be explored. This study investigated the role of IL-6 in lung adenocarcinoma cell EMT and explored the potential effects of metformin on this process. Methods Invasion assay and MTT assay was performed to determine cell invasion and cell proliferation. Western blotting, immunofluorescence, real-time PCR, ELISA, and immunohistochemistry were performed to detect the expression of IL-6, E-cadherin, Vimentin, and p-STAT3. Results We discovered that IL-6, via STAT3 phosphorylation, could promote lung adenocarcinoma cell invasion via EMT in vitro. This was supported by the inverse correlation between E-cadherin and IL-6 expression, positive correlation between IL-6 and vimentin mRNA expression and between STAT3 phosphorylation and IL-6 expression in tumor tissues. Importantly, metformin inhibited tumor growth and distant metastases in tumor-bearing nude mice and reversed IL-6-induced EMT both in vitro and in vivo. Furthermore, we found that blockade of STAT3 phosphorylation might be the underlying mechanism of metformin inhibition of IL-6-induced EMT. Conclusions Collectively, our present results show that enhanced IL-6 expression, via STAT3 phosphorylation, is a mechanism of EMT in lung adenocarcinoma. We found that metformin could inhibit IL-6-induced EMT possibly by blocking STAT3 phosphorylation. PMID:24789104

  4. Effects of metformin on inflammation and short-term memory in streptozotocin-induced diabetic mice.

    PubMed

    Oliveira, Wilma Helena; Nunes, Ana Karolina; França, Maria Eduarda Rocha; Santos, Laise Aline; Lós, Deniele Bezerra; Rocha, Sura Wanessa; Barbosa, Karla Patrícia; Rodrigues, Gabriel Barros; Peixoto, Christina Alves

    2016-08-01

    The aim of the present study was to analyze the action of metformin on short-term memory, glial cell activation and neuroinflammation caused by experimental diabetic encephalopathy in C57BL/6 mice. Diabetes was induced by the intraperitoneal injection of a dose of 90mg/kg of streptozotocin on two successive days. Mice with blood glucose levels ≥200dl/ml were considered diabetic and were given metformin hydrochloride at doses of 100mg/kg and 200mg/kg (by gavage, twice daily) for 21 days. On the final day of treatment, the mice underwent a T-maze test. On the 22nd day of treatment all the animals were anesthetized and euthanized. Diabetic animals treated with metformin had a higher spatial memory score. The hippocampus of the diabetic animals presented reactive gliosis, neuronal loss, NF-kB signaling activation, and high levels of IL-1 and VEGF. In addition, the T-maze test scores of these animals were low. Treatment with metformin reduced the expression of GFAP, Iba-1 (astrocyte and microglial markers) and the inflammation markers (p-IKB, IL-1 and VEGF), while enhancing p-AMPK and eNOS levels and increasing neuronal survival (Fox-1 and NeuN). Treatment with metformin also improved the spatial memory scores of diabetic animals. In conclusion, the present study showed that metformin can significantly reduce neuroinflammation and can decrease the loss of neurons in the hippocampus of diabetic animals, which can subsequently promote improvements in spatial memory. PMID:27174003

  5. Antiatherosclerotic and Cardioprotective Potential of Acacia senegal Seeds in Diet-Induced Atherosclerosis in Rabbits

    PubMed Central

    Ram, Heera; Jatwa, Rameshwar; Purohit, Ashok

    2014-01-01

    Acacia senegal L. (Fabaceae) seeds are essential ingredient of “Pachkutta,” a specific Rajasthani traditional food. The present study explored antiatherosclerotic and cardioprotective potential of Acacia senegal seed extract, if any, in hypercholesterolemic diet-induced atherosclerosis in rabbits. Atherosclerosis in rabbits was induced by feeding normal diet supplemented with oral administration of cholesterol (500 mg/kg body weight/day mixed with coconut oil) for 15 days. Circulating total cholesterol (TC), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), triglycerides, and VLDL-cholesterol (VLDL-C) levels; atherogenic index (AI); cardiac lipid peroxidation (LPO); planimetric studies of aortal wall; and histopathological studies of heart, aorta, kidney, and liver were performed. Apart from reduced atherosclerotic plaques in aorta (6.34 ± 0.72) and increased lumen volume (51.65 ± 3.66), administration with ethanolic extract of Acacia senegal seeds (500 mg/kg/day, p.o.) for 45 days to atherosclerotic rabbits significantly lowered serum TC, LDL-C, triglyceride, and VLDL-C levels and atherogenic index as compared to control. Atherogenic diet-induced cardiac LPO and histopathological abnormalities in aorta wall, heart, kidney, and liver were reverted to normalcy by Acacia senegal seed extract administration. The findings of the present study reveal that Acacia senegal seed extract ameliorated diet-induced atherosclerosis and could be considered as lead in the development of novel therapeutics. PMID:25544897

  6. Two weeks of metformin treatment induces AMPK-dependent enhancement of insulin-stimulated glucose uptake in mouse soleus muscle

    PubMed Central

    Kristensen, Jonas Møller; Treebak, Jonas T.; Schjerling, Peter; Goodyear, Laurie

    2014-01-01

    Metformin-induced activation of the 5′-AMP-activated protein kinase (AMPK) has been associated with enhanced glucose uptake in skeletal muscle, but so far no direct causality has been examined. We hypothesized that an effect of in vivo metformin treatment on glucose uptake in mouse skeletal muscles is dependent on AMPK signaling. Oral doses of metformin or saline treatment were given to muscle-specific kinase dead (KD) AMPKα2 mice and wild-type (WT) littermates either once or chronically for 2 wk. Soleus and extensor digitorum longus muscles were used for measurements of glucose transport and Western blot analyses. Chronic treatment with metformin enhanced insulin-stimulated glucose uptake in soleus muscles of WT (∼45%, P < 0.01) but not of AMPK KD mice. Insulin signaling at the level of Akt protein expression or Thr308 and Ser473 phosphorylation was not changed by metformin treatment. Insulin signaling at the level of Akt and TBC1D4 protein expression as well as Akt Thr308/Ser473 and TBC1D4 Thr642/Ser711 phosphorylation were not changed by metformin treatment. Also, protein expressions of Rab4, GLUT4, and hexokinase II were unaltered after treatment. The acute metformin treatment did not affect glucose uptake in muscle of either of the genotypes. In conclusion, we provide novel evidence for a role of AMPK in potentiating the effect of insulin on glucose uptake in soleus muscle in response to chronic metformin treatment. PMID:24644243

  7. Cardioprotective Effect of Phenytoin on Doxorubicin-induced Cardiac Toxicity in a Rat Model.

    PubMed

    Razmaraii, Nasser; Babaei, Hossein; Mohajjel Nayebi, Alireza; Asadnasab, Gholamreza; Ashrafi Helan, Javad; Azarmi, Yadollah

    2016-03-01

    Doxorubicin (DOX) is an effective anticancer agent, but adverse cardiotoxic effects limit its use. Compounds reducing DOX cardiotoxicity could improve its therapeutic index. This study investigated the protective effects of phenytoin (Phen) for DOX-induced cardiomyopathy. Male Wistar rats were randomized into 5 groups to receive either saline, DOX (2 mg/kg per 48 hours, 6 doses, intraperitoneally) or DOX + Phen (5, 10, or 20 mg/kg/d, starting 4 days before DOX, intraperitoneally). The animals were assessed 24 hours after the last injection. Left ventricular (LV) function and hemodynamic parameters were assessed using transthoracic echocardiography, electrocardiography, and a Millar pressure catheter. Histopathological studies were performed, and the effect of Phen on the cytotoxicity of DOX was evaluated in vitro for the human breast adenocarcinoma cell line. DOX-impaired LV function significantly decreased the LV systolic and diastolic pressures, rate of rise/decrease of LV pressure, ejection fraction, fractional shortening, and contractility index. DOX caused structural changes in myocardial cells. Treatment with Phen decreased DOX-induced toxicity, significantly improved ventricular function, and ameliorated structural changes in the myocardium. Phen also did not interfere with the antitumor effect of DOX. The results confirm the cardioprotective effect of Phen against DOX-induced cardiomyopathy without removing antitumor effect of DOX. PMID:26544684

  8. Metformin prevents ischemia reperfusion-induced oxidative stress in the fatty liver by attenuation of reactive oxygen species formation.

    PubMed

    Cahova, Monika; Palenickova, Eliska; Dankova, Helena; Sticova, Eva; Burian, Martin; Drahota, Zdenek; Cervinkova, Zuzana; Kucera, Otto; Gladkova, Christina; Stopka, Pavel; Krizova, Jana; Papackova, Zuzana; Oliyarnyk, Olena; Kazdova, Ludmila

    2015-07-15

    Nonalcoholic fatty liver disease is associated with chronic oxidative stress. In our study, we explored the antioxidant effect of antidiabetic metformin on chronic [high-fat diet (HFD)-induced] and acute oxidative stress induced by short-term warm partial ischemia-reperfusion (I/R) or on a combination of both in the liver. Wistar rats were fed a standard diet (SD) or HFD for 10 wk, half of them being administered metformin (150 mg·kg body wt(-1)·day(-1)). Metformin treatment prevented acute stress-induced necroinflammatory reaction, reduced alanine aminotransferase and aspartate aminotransferase serum activity, and diminished lipoperoxidation. The effect was more pronounced in the HFD than in the SD group. The metformin-treated groups exhibited less severe mitochondrial damage (markers: cytochrome c release, citrate synthase activity, mtDNA copy number, mitochondrial respiration) and apoptosis (caspase 9 and caspase 3 activation). Metformin-treated HFD-fed rats subjected to I/R exhibited increased antioxidant enzyme activity as well as attenuated mitochondrial respiratory capacity and ATP resynthesis. The exposure to I/R significantly increased NADH- and succinate-related reactive oxygen species (ROS) mitochondrial production in vitro. The effect of I/R was significantly alleviated by previous metformin treatment. Metformin downregulated the I/R-induced expression of proinflammatory (TNF-α, TLR4, IL-1β, Ccr2) and infiltrating monocyte (Ly6c) and macrophage (CD11b) markers. Our data indicate that metformin reduces mitochondrial performance but concomitantly protects the liver from I/R-induced injury. We propose that the beneficial effect of metformin action is based on a combination of three contributory mechanisms: increased antioxidant enzyme activity, lower mitochondrial ROS production, and reduction of postischemic inflammation. PMID:26045616

  9. Metformin protects against seizures, learning and memory impairments and oxidative damage induced by pentylenetetrazole-induced kindling in mice.

    PubMed

    Zhao, Ran-Ran; Xu, Xiao-Chen; Xu, Fei; Zhang, Wei-Li; Zhang, Wen-Lin; Liu, Liang-Min; Wang, Wei-Ping

    2014-06-13

    Cognitive impairment, the most common and severe comorbidity of epilepsy, greatly diminishes the quality of life. However, current therapeutic interventions for epilepsy can also cause untoward cognitive effects. Thus, there is an urgent need for new kinds of agents targeting both seizures and cognition deficits. Oxidative stress is considered to play an important role in epileptogenesis and cognitive deficits, and antioxidants have a putative antiepileptic potential. Metformin, the most commonly prescribed antidiabetic oral drug, has antioxidant properties. This study was designed to evaluate the ameliorative effects of metformin on seizures, cognitive impairment and brain oxidative stress markers observed in pentylenetetrazole-induced kindling animals. Male C57BL/6 mice were administered with subconvulsive dose of pentylenetetrazole (37 mg/kg, i.p.) every other day for 14 injections. Metformin was injected intraperitoneally in dose of 200mg/kg along with alternate-day PTZ. We found that metformin suppressed the progression of kindling, ameliorated the cognitive impairment and decreased brain oxidative stress. Thus the present study concluded that metformin may be a potential agent for the treatment of epilepsy as well as a protective medicine against cognitive impairment induced by seizures. PMID:24802403

  10. FSTL1 as a Potential Mediator of Exercise-Induced Cardioprotection in Post-Myocardial Infarction Rats.

    PubMed

    Xi, Yue; Gong, Da-Wei; Tian, Zhenjun

    2016-01-01

    Exercise training has been reported to ameliorate heart dysfunction in both humans and animals after myocardial infarction (MI), but the underlying mechanisms are poorly understood. Follistatin-like1 (FSTL1) is a cardioprotective factor against ischemic injury and is induced in cardiomyocytes and skeletal muscle in ischemic and hypoxic conditions. To test the hypothesis that FSTL1 may be a molecular link between exercise and improved heart function post MI, we subjected MI-rats, induced by left coronary artery ligation, to two modes of exercise: intermittent aerobic exercise (IAE) or mechanical vibration training (MVT), for four weeks and examined the relevance of FSTL1 to exercise-mediated cardiac effects. Exercise improved the functional performance, reduced fibrosis of MI-hearts and induced FSTL1 expression, the TGFβ-Smad2/3 signaling and angiogenesis in myocardium. In gastrocnemius, exercise increased the cross-sectional area of myocytes and FSTL1 expression. Importantly, exercise increased circulating FSTL1 levels, which were positively correlated with the skeletal muscle FSTL1 expression and negatively correlated with heart fibrosis. Overall, the IAE was more effective than that of MVT in cardioprotection. Finally, exogenous FSTL1 administration directly improved angiogenesis as well as functionality of post-MI hearts. Taken together, we have demonstrated that FSTL1 is a potential mediator of exercise-induced cardioprotection in post-MI rats. PMID:27561749

  11. FSTL1 as a Potential Mediator of Exercise-Induced Cardioprotection in Post-Myocardial Infarction Rats

    PubMed Central

    Xi, Yue; Gong, Da-Wei; Tian, Zhenjun

    2016-01-01

    Exercise training has been reported to ameliorate heart dysfunction in both humans and animals after myocardial infarction (MI), but the underlying mechanisms are poorly understood. Follistatin-like1 (FSTL1) is a cardioprotective factor against ischemic injury and is induced in cardiomyocytes and skeletal muscle in ischemic and hypoxic conditions. To test the hypothesis that FSTL1 may be a molecular link between exercise and improved heart function post MI, we subjected MI-rats, induced by left coronary artery ligation, to two modes of exercise: intermittent aerobic exercise (IAE) or mechanical vibration training (MVT), for four weeks and examined the relevance of FSTL1 to exercise-mediated cardiac effects. Exercise improved the functional performance, reduced fibrosis of MI-hearts and induced FSTL1 expression, the TGFβ-Smad2/3 signaling and angiogenesis in myocardium. In gastrocnemius, exercise increased the cross-sectional area of myocytes and FSTL1 expression. Importantly, exercise increased circulating FSTL1 levels, which were positively correlated with the skeletal muscle FSTL1 expression and negatively correlated with heart fibrosis. Overall, the IAE was more effective than that of MVT in cardioprotection. Finally, exogenous FSTL1 administration directly improved angiogenesis as well as functionality of post-MI hearts. Taken together, we have demonstrated that FSTL1 is a potential mediator of exercise-induced cardioprotection in post-MI rats. PMID:27561749

  12. Cardioprotective effect of lipistat against doxorubicin induced myocardial toxicity in albino rats.

    PubMed

    Koti, B C; Vishwanathswamy, A H M; Wagawade, Jyoti; Thippeswamy, A H M

    2009-01-01

    Preventive role of lipistat against doxorubicin induced myocardial toxicity in rats has been reported. Cardiotoxicity was produced by doxorubicin administration (15 mg/kg for 2 weeks). Lipistat (350 mg/kg, orally) was administered as pretreatment for 2 weeks and then for 2 weeks alternated with doxorubicin. The general observations, mortality, histopathology, biomarker enzymes like lactate dehydrogenase (LDH) and creatine phosphokinase (CPK), serum lipid profiles like total cholesterol, triglycerides, low-density lipoprotein (LDL) and high-density lipoprotein (HDL), antioxidant enzymes such as glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were monitored after 3 weeks of last dose. Pretreatment with the lipistat significantly protected myocardium from the toxic effects of doxorubicin by reducing the elevated level of biomarker enzymes like LDH and CPK to the normal and serum lipids such as total cholesterol, triglyceride and LDL back to normal. Lipistat increases the decreased level of GSH, SOD and CAT and decreases the increased level of malondialdehyde in cardiac tissue. The repeated administration of doxorubicin causes cardiomyopathy associated with an antioxidant deficit and increased level of lipid profiles by interfering with fatty acid metabolism. The results support the lipid lowering and antioxidant properties of lipistat, which indicate the cardioprotective property against doxorubicin induced cardiotoxicity. PMID:19317350

  13. The Antioxidant Potential of Azadirachta indica Ameliorates Cardioprotection Following Diabetic Mellitus-Induced Microangiopathy

    PubMed Central

    Gupta, Naveen Kumar; Srivastva, Nidhi; Bubber, Parvesh; Puri, Sanjeev

    2016-01-01

    Background: Cardiac complications associated with diabetes mellitus have become major cause of concern. Antidiabetic drugs, with varied mode of action, are although available, apprehensions exist for their limited action or side effects upon prolonged use. Efforts are therefore inclined toward finding other alternatives. The present study was, thus, undertaken to evaluate the cardioprotective effect of Azadirachta indica (AI) on microangiopathic changes in rat model of diabetes. Materials and Methods: Diabetes was induced in male rats by single intraperitoneal injection of streptozotocin (60 mg/kg body weight). Seven days after glucose levels are stabilized, aqueous leaf extract of AI (ALE) (600 mg/kg1 body weight) was administered orally to diabetic animals every day for 7 days. Results: High blood glucose characterizing diabetes in these animals was found to show increased lipid peroxidation (LPO), altered antioxidant biomarkers together with microangiopathic alterations. The treatment of diabetic rats with ALE reduced the levels of blood glucose, LPO, and restored the activities of antioxidant enzyme. Light and transmission electron microscopic analysis revealed reduced necrotic areas and inflammation in tissue architecture of ALE treated heart in comparison to untreated diabetic group. Conclusion: AI provides cardioprotection by ameliorating oxidative stress in rat model of diabetic mellitus. SUMMARY The streptozotocin (STZ) treatment (60 mg/kg body weight) to animals induced diabetic changes such as elevated blood glucose levels, decreased body weight, altered lipid profiles together with development of proxidant state evidenced by elevated levels of lipid peroxidation (LPO), depletion in reduced glutathione (GSH) levels and altered antioxidant enzymes with consequent microangiopathic alterations in heart tissue evinced by localization of necrotic and inflamed areas in heart tissueThe treatment of animals with Azadirachta indica leaf extract (ALE) (600 mg

  14. Synergistic interaction between metformin and sulfonylureas on diclofenac-induced antinociception measured using the formalin test in rats

    PubMed Central

    Ortiz, Mario I

    2013-01-01

    BACKGROUND There is evidence that biguanides and sulfonylureas block diclofenac-induced antinociception (DIA) in rat models. However, little is known about the interaction between these hypoglycemics with respect to DIA. OBJECTIVE: To determine whether metformin-sulfonylurea combinations affect DIA during the formalin test. METHODS: Rats received the appropriate vehicle or diclofenac before 1% formaldehyde was injected into the paw. Rats were also pretreated with vehicle, glibenclamide, glipizide, metformin or glibenclamide/metformin and glipizide/metformin combinations before the diclofenac and formaldehyde injections, and the effect on antinociception was assessed. Isobolograms of the combinations were constructed to test for a synergistic interaction. RESULTS: Systemic injection of diclofenac resulted in antinociception during the second phase of the test. Systemic pretreatment with the combinations of glibenclamide (0.56 mg/kg to 10 mg/kg)/metformin (10 mg/kg to 180 mg/kg) and glipizide (0.56 mg/kg to10 mg/kg)/metformin (10 mg/kg to 180 mg/kg) blocked DIA. The derived theoretical effective doses for 50% of subjects (ED50) for the glibenclamide/metformin and glipizide/metformin combinations were 32.52 mg/kg and 32.42 mg/kg, respectively, and were significantly higher than the actual observed experimental ED50 values (7.57 mg/kg and 8.43 mg/kg, respectively). CONCLUSION: Pretreatment with glibenclamide, glipizide or metformin blocked DIA in a dose-dependent manner, and combining either sulfonylurea with metformin produced even greater effects. The observed ED50s for the combinations were approximately fourfold lower than the calculated additive effects. These data indicate that sulfonylureas interact to produce antagonism of DIA. Combination therapy is a common second-line treatment for patients with diabetes and metabolic syndrome, a group that experiences pain from multiple sources. The results suggest that at least some anti-inflammatory agents may not be

  15. Cardioprotective effect of Saraca indica against cyclophosphamide induced cardiotoxicity in rats: A biochemical, electrocardiographic and histopathological study

    PubMed Central

    Viswanatha Swamy, A. H. M.; Patel, U. M.; Koti, B. C.; Gadad, P. C.; Patel, N. L.; Thippeswamy, A. H. M.

    2013-01-01

    Objectives: Cardioprotective activity of alcoholic extract of Saraca indica (SI) bark was investigated against cyclophosphamide induced cardiotoxicity. Materials and Methods: Cardiotoxicity was induced in Wistar rats by administering cyclophosphamide (200 mg/kg, i.p.) single injection on first day of experimental period. Saraca indica (200 and 400 mg/kg, p.o.) was administered immediately after administration of cyclophosphamide on first day and daily for 10 days. The general observations and mortality were measured. Results: Cyclophosphamide administration significantly (p < 0.05) increased lipid peroxidation (LPO) and decreased the levels of antioxidant markers such as reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). Cyclophosphamide elevated the levels of biomarker enzymes like creatine kinase (CK), creatine kinase isoenzyme MB (CK-MB), lactate dehydrogenase (LDH), aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP). Further, the cyclophosphamide treated rats showed changes in electrocardiogram (ECG) along with increased levels of cholesterol and triglycerides. Treatment with Saraca indica significantly (p < 0.05) reversed the status of cardiac biomarkers, ECG, oxidative enzymes and lipid profile in cyclophosphamide induced cardiotoxicity. Potential cardioprotective effect of Saraca indica was supported by histopathological examination that reduced severity of cellular damage of the myocardium. Conclusion: The biochemical, ECG and histopathology reports support the cardioprotective effect of Saraca indica which could be attributed to antioxidant activity. PMID:23543849

  16. Metformin prevents endoplasmic reticulum stress-induced apoptosis through AMPK-PI3K-c-Jun NH2 pathway

    USGS Publications Warehouse

    Jung, T.W.; Lee, M.W.; Lee, Y.-J.; Kim, S.M.

    2012-01-01

    Type 2 diabetes mellitus is thought to be partially associated with endoplasmic reticulum (ER) stress toxicity on pancreatic beta cells and the result of decreased insulin synthesis and secretion. In this study, we showed that a well-known insulin sensitizer, metformin, directly protects against dysfunction and death of ER stress-induced NIT-1 cells (a mouse pancreatic beta cell line) via AMP-activated protein kinase (AMPK) and phosphatidylinositol-3 (PI3) kinase activation. We also showed that exposure of NIT-1 cells to metformin (5mM) increases cellular resistance against ER stress-induced NIT-1 cell dysfunction and death. AMPK and PI3 kinase inhibitors abolished the effect of metformin on cell function and death. Metformin-mediated protective effects on ER stress-induced apoptosis were not a result of an unfolded protein response or the induced inhibitors of apoptotic proteins. In addition, we showed that exposure of ER stressed-induced NIT-1 cells to metformin decreases the phosphorylation of c-Jun NH(2) terminal kinase (JNK). These data suggest that metformin is an important determinant of ER stress-induced apoptosis in NIT-1 cells and may have implications for ER stress-mediated pancreatic beta cell destruction via regulation of the AMPK-PI3 kinase-JNK pathway.

  17. Upregulated Hsp27 expression in the cardioprotection induced by acute stress and oxytocin in ischemic reperfused hearts of the rat.

    PubMed

    Moghimian, Maryam; Faghihi, Mahdieh; Karimian, Seyed Morteza; Imani, AliReza; Mobasheri, Maryam Beigom

    2014-12-31

    In view of the cardioprotective effect of oxytocin (OT) released in response to stress, the aim of this study was to evaluate the role of heat shock proteins Hsps 70, 27 and 20 in stress-induced cardioprotection in isolated, perfused rat hearts. Rats were divided in two main groups: unstressed and stressed rats, and all of them were subjected to i.c.v. infusion of vehicle or drugs: unstressed rats [control: vehicle, OT (100 ng/5 μl), atosiban (ATO; 4.3 μg/5 μl) as OT antagonist, ATO+OT], and stressed rats [St: stress, OT+St, ATO+St]. After anesthesia, hearts were isolated and subjected to 30 min regional ischemia and 60 min subsequent reperfusion (IR). Acute stress protocol included swimming for 10 min before anesthesia. Malondialdehyde in coronary effluent was measured and the expression of Hsp 70, 27 and 20 was measured in myocardium using real-time reverse transcriptase polymerase chain reaction (RT-PCR). The malondialdehyde levels, which decreased in the St and OT groups, increased by the administration of atosiban as an OT antagonist. The expression of Hsp27 increased 4 to 5 folds by stress induction and i.c.v. infusion of OT. Central administration of atosiban prior to both stress and OT decreased Hsp27 mRNA levels. These findings suggest that endogenous OT may participate in stress-induced cardioprotection via Hsp27 over-expression as an early response. PMID:25575521

  18. Far red/near infrared light-induced cardioprotection under normal and diabetic conditions

    NASA Astrophysics Data System (ADS)

    Keszler, Agnes; Baumgardt, Shelley; Hwe, Christopher; Bienengraeber, Martin

    2015-03-01

    Far red/near infrared light (NIR) is beneficial against cardiac ischemia and reperfusion injury (I/R), although the exact underlying mechanism is unknown. Previously we established that NIR enhanced the cardioprotective effect of nitrite in the rabbit heart. Furthermore, we observed that the nitrosyl myoglobin (MbNO) level in ischemic tissue decreased upon irradiation of the heart. Our hypothesis was that protection against I/R is dependent on nitric oxide (NO)-release from heme-proteins, and remains present during diabetes. When mice were subjected to I/R NIR (660 nm) applied during the beginning of reperfusion reduced infarct size dose dependently compared to untreated animals. Similarly, the isolated (Langendorff) heart model resulted in sustained left ventricular diastolic pressure after I/R in NIR-treated hearts. NIRinduced protection was preserved in a diabetic mouse model (db/db) and during acute hyperglycemia. NIR liberated NO from nitrosyl hemoglobin (HbNO) and MbNO as well as from HbNO isolated from the blood of diabetic animals. In the Langendorff model, after application of the nitrosylated form of a hemoglobin-based oxygen carrier as an NO donor NIR induced an increase in NADH level, suggesting a mild inhibition of mitochondrial respiration by NO during reperfusion. Taken together, NIR applied during reperfusion protects the myocardium against I/R in a NO-dependent and mitochondrion-targeted manner. This unique mechanism is conserved under diabetic conditions where other protective strategies fail.

  19. Metformin reduces the endotoxin-induced down-regulation of apolipoprotein E gene expression in macrophages

    SciTech Connect

    Stavri, Simona; Trusca, Violeta G.; Simionescu, Maya; Gafencu, Anca V.

    2015-05-29

    The atheroprotective role of macrophage-derived apolipoprotein E (apoE) is well known. Our previous reports demonstrated that inflammatory stress down-regulates apoE expression in macrophages, aggravating atherogenesis. Metformin, extensively used as an anti-diabetic drug, has also anti-inflammatory properties, and thus confers vascular protection. In this study, we questioned whether metformin could have an effect on apoE expression in macrophages in normal conditions or under lipopolysaccharide (LPS)-induced stress. The results showed that metformin slightly increases the apoE expression only at high doses (5–10 mM). Low doses of metformin (1–3 mM) significantly reduce the LPS down-regulatory effect on apoE expression in macrophages. Our experiments demonstrated that LPS-induced NF-κB binds to the macrophage-specific distal regulatory element of apoE gene, namely to the multienhancer 2 (ME.2) and its 5′-deletion fragments. The NF-κB binding on ME.2 and apoE promoter has a down-regulatory effect. In addition, data revealed that metformin impairs NF-κB nuclear translocation, and thus, improves the apoE levels in macrophages under inflammatory stress. The positive effect of metformin in the inflammatory states, its clinical safety and low cost, make this drug a potential adjuvant in the therapeutic strategies for atherosclerosis. - Highlights: • High doses of metformin slightly increase apoE expression in macrophages. • Low doses of metformin up-regulate apoE gene in endotoxin-stressed macrophages. • Metformin reduces the negative effect of LPS on apoE expression by NF-κB inhibition.

  20. Effect of natural honey from Ilam and metformin for improving glycemic control in streptozotocin-induced diabetic rats

    PubMed Central

    Nasrolahi, Ozra; Heidari, Reza; Rahmani, Fatima; Farokhi, Farah

    2012-01-01

    Objective(s): Diabetes mellitus is a public health problem and one of the five leading causes of death globally. In the present study, the effect of Metformin with natural honey was investigated on glycemia in the Streptozotocin-induced diabetic rats. Materials and Methods: Thirty Wistar male rats were randomly divided into six groups including C: non diabetic rats received distilled water, CH: non diabetic rats received honey, CD: diabetic rats administered with distilled water, DM: Metformin treated diabetic rats, DH: honey treated diabetic rats, and DMH: diabetic rats treated with a combination of Metformin and natural honey. Diabetes was induced by a single dose of Streptozotocin (65 mg/kg; i.p.). The animals were treated by oral gavage once daily for four weeks. At the end of the treatment period, the animals were sacrificed and their blood samples collected. Amount of glucose, triglyceride (TG), total cholesterol (TC), HDL cholesterol, LDL cholesterol, VLDL cholesterol, total bilirubin, and albumin were determined in serum. Results: Group CD: showed hyperglycemia (252.2±4.1 mg/dl), while level of blood glucose was significantly (p<0.01) reduced in groups DH (124.2±2.7 mg/dl), DM (108.0±3.4 mg/dl), and DMH (115.4±2.1 mg/dl). Honey in combination with Metformin significantly (p<0.01) reduced level of bilirubin but Metformin alone did not reduce bilirubin. Honey alone and in combination with Metformin also significantly reduced triglycerides, total cholesterol, LDL, VLDL and increased HDL, but Metformin did not reduced triglycerides and increased HDL. Conclusion: The results of the present study demonstrated that consuming natural honey with Metformin improves glycemic control and is more useful than consuming Metformin alone. The higher therapeutic effect of Ilam honey on lipid abnormalities than Tualang honey was also evident. PMID:25050251

  1. Metformin protects against hyperglycemia-induced cardiomyocytes injury by inhibiting the expressions of receptor for advanced glycation end products and high mobility group box 1 protein.

    PubMed

    Zhang, Ting; Hu, Xiaorong; Cai, Yuli; Yi, Bo; Wen, Zhongyuan

    2014-03-01

    Metformin (MET), an anti-diabetic oral drug with antioxidant properties, has been proved to provide cardioprotective effects in patients with diabetic disease. However, the mechanism is unclear. This study aimd to investigate the effects of MET on the expressions of receptor for advanced glycation end products (RAGE) and high mobility group box 1 protein (HMGB1) in hyperglycemia-treated neonatal rat ventricular myocytes. Cardiocytes were prepared and cultured with high glucose and different concentrations of MET. The expressions of RAGE and HMGB1 were evaluated by Western blot analysis. The superoxide dismutase (SOD), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), lactate dehydrogenase (LDH) and creatine kinase (CK) were measured. After 12 h-incubation, MET significantly inhibited the increase of MDA, TNF-α, LDH and CK levels induced by high glucose, especially at the 5 × 10(-5) to 10(-4 )mol/L concentrations while inhibiting the decrease of SOD level. Meanwhile, RAGE and HMGB1 expression were significantly increased induced by hyperglycaemia for 24 h (P < 0.05). MET inhibited the expressions of RAGE and HMGB1 in a dose-dependent manner, especially at the 5 × 10(-5) to 10(-4 )mol/L concentrations (P < 0.05). In conclusion, our study suggested that MET could reduce hyperglycemia-induced cardiocytes injury by inhibiting the expressions of RAGE and HMGB1. PMID:24420848

  2. mTORC2 Phosphorylation of Akt1: A Possible Mechanism for Hydrogen Sulfide-Induced Cardioprotection

    PubMed Central

    Zhou, Yue; Wang, Daying; Gao, Xiufang; Lew, Karsheng; Richards, Arthur Mark; Wang, Peipei

    2014-01-01

    Hydrogen sulfide (H2S) is known to have cardiac protective effects through Akt activation. Akt acts as a ‘central sensor’ for myocyte survival or death; its activity is regulated by multiple kinases including PI3K, mTORC2, PDK1 and phosphatases including PTEN, PP2A and PHLPPL. Based on the previous finding that PI3K inhibitor LY294002 abolishes H2S-induced Akt phosphorylation and cardioprotection, it is accepted that PI3K is the mediator of H2S-induced Akt phosphorylation. However, LY294002 inhibits both PI3K and mTOR, and PI3K only recruits Akt to the membrane where Akt is phosphorylated by Akt kinases. We undertook a series of experiments to further evaluate the role of mTORC2, PDK1, PTEN, PP2A and PHLPPL in H2S-induced Akt phosphorylation and cardioprotection, which, we believe, has not been investigated before. Hearts from adult Sprague-Dawley rats were isolated and subjected to (i) normoxia, (ii) global ischemia and (iii) ischemia/reperfusion in the presence or absence of 50 µM of H2S donor NaHS. Cardiac mechanical function and lactate dehydrogenase (LDH) release were assessed. All hearts also were Western analyzed at the end of perfusion for Akt and a panel of appropriate Akt regulators and targets. Hearts pretreated with 50 µM NaHS had improved function at the end of reperfusion (Rate pressure product; 19±4×103 vs. 10±3×103 mmHg/min, p<0.05) and reduced cell injury (LDH release 19±10 vs. 170±87 mU/ml p<0.05) compared to untreated hearts. NaHS significantly increased phospho-Akt, phospho-mTOR, phospho-Bim and Bcl-2 in reperfused hearts (P<0.05). Furthermore using H9c2 cells we demonstrate that NaHS pretreatment reduces apoptosis following hypoxia/re-oxygenation. Importantly, PP242, a specific mTOR inhibitor, abolished both cardioprotection and protein phosphorylation in isolated heart and reduced apoptotic effects in H9c2 cells. Treating hearts with NaHS only during reperfusion produced less cardioprotection through a similar mechanism. These data

  3. Cardioprotective effects of nicorandil, a mitochondrial potassium channel opener against doxorubicin-induced cardiotoxicity in rats.

    PubMed

    Abdel-Raheem, Ihab T; Taye, Ashraf; Abouzied, Mekky M

    2013-09-01

    Doxorubicin is a chemotherapeutic drug used to treat solid and haematopoietic tumours. Its use is limited by a major side effect of cardiotoxicity. It was reported that doxorubicin-induced cardiotoxicity is mediated through oxidative stress coupled with impaired NO bioavailability and NF-κB activation. Nicorandil, a mitochondrial ATP-dependent potassium (KATP ) channel opener, was reported to be cardioprotective on ischaemic myocardium. However, the effect of nicorandil against doxorubicin-induced cardiotoxicity has not yet been clarified. Accordingly, six groups of rats were used. The first three groups were injected with vehicle, nicorandil (3 mg/kg) orally and doxorubicin (a single intraperitoneal injection of 20 mg/kg), respectively. Group four was treated with nicorandil, whereas group five was treated with glibenclamide and then nicorandil starting 2 days before doxorubicin and continued for five consecutive days. Group six was treated with glibenclamide alone. At the end of the experiment, the rats were killed. Cardiac enzyme indexes were measured in serum. Heart tissues were processed for determination of nitrite/nitrate, NF-κB protein expression, glutathione (GSH), lipid peroxide (TBARS) levels and superoxide production. In addition to body-weight reduction, doxorubicin produced cardiotoxicity as indicated from the increase in lactate dehydrogenase (LDH), creatine kinase (CK) activities, TBARS, superoxide production, NF-κB expression and caspase-3 activity. Moreover, doxorubicin decreased GSH and nitrite/nitrate levels. Histopathological examination of doxorubicin-treated hearts revealed degenerative changes. On the other hand, nicorandil protected cardiac tissues against doxorubicin cardiotoxicity as demonstrated from normalization of cardiac biochemical and oxidative stress parameters and amelioration of histopathological changes. Glibenclamide, a blocker of the KATP channel, reversed most of the cardiac effects of nicorandil. PMID:23621757

  4. Metformin protects against the development of fructose-induced steatosis in mice: role of the intestinal barrier function.

    PubMed

    Spruss, Astrid; Kanuri, Giridhar; Stahl, Carolin; Bischoff, Stephan C; Bergheim, Ina

    2012-07-01

    To test the hypothesis that metformin protects against fructose-induced steatosis, and if so, to elucidate underlying mechanisms, C57BL/6J mice were either fed 30% fructose solution or plain water for 8 weeks. Some of the animals were concomitantly treated with metformin (300 mg/kg body weight/day) in the drinking solution. While chronic consumption of 30% fructose solution caused a significant increase in hepatic triglyceride accumulation and plasma alanine-aminotransferase levels, this effect of fructose was markedly attenuated in fructose-fed mice concomitantly treatment with metformin. The protective effects of the metformin treatment on the onset of fructose-induced non-alcoholic fatty liver disease (NAFLD) were associated with a protection against the loss of the tight junction proteins occludin and zonula occludens 1 in the duodenum of fructose-fed mice and the increased translocation of bacterial endotoxin found in mice only fed with fructose. In line with these findings, in metformin-treated fructose-fed animals, hepatic expression of genes of the toll-like receptor-4-dependent signalling cascade as well as the plasminogen-activator inhibitor/cMet-regulated lipid export were almost at the level of controls. Taken together, these data suggest that metformin not only protects the liver from the onset of fructose-induced NAFLD through mechanisms involving its direct effects on hepatic insulin signalling but rather through altering intestinal permeability and subsequently the endotoxin-dependent activation of hepatic Kupffer cells. PMID:22525431

  5. Metformin-Induced Killing of Triple Negative Breast Cancer Cells is Mediated by Reduction in Fatty Acid Synthase via miRNA-193b

    PubMed Central

    Wahdan-Alaswad, Reema S.; Cochrane, Dawn R.; Spoelstra, Nicole S.; Howe, Erin N.; Edgerton, Susan M.; Anderson, Steven M.; Thor, Ann D.; Richer, Jennifer K.

    2015-01-01

    The anti-diabetic drug metformin (1,1-dimethylbiguanide hydrochloride) reduces both the incidence and mortality of several types of cancer. Metformin has been shown to selectively kill cancer stem cells and triple negative breast cancer (TNBC) cell lines are more sensitive to the effects of metformin. However, the mechanism underlying the enhanced susceptibility of TNBC to metformin had not been elucidated. Expression profiling of metformin-treated TNBC lines revealed fatty acid synthase (FASN) as one of the genes most significantly downregulated following 24 hours of treatment and a decrease in FASN protein was also observed. Since FASN is critical for de novo fatty acid synthesis, and is important for survival of TNBC, we hypothesized that FASN downregulation facilitates metformin-induced apoptosis. Profiling studies also exposed a rapid metformin-induced increase in miR-193 family members, and miR-193b was found to directly target the FASN 3′UTR. Addition of exogenous miR-193b mimic to untreated TNBC cells resulted in decreased FASN protein expression and increased apoptosis of TNBC cells, while spontaneously immortalized, non-transformed breast epithelial cells remained unaffected. Conversely, antagonizing miR-193 activity impaired the ability of metformin to decrease FASN and cause cell death. Further, the metformin-stimulated increase in miR-193 resulted in reduced mammosphere formation by TNBC lines. These studies provide mechanistic insight into the metformin-induced killing of TNBC. PMID:25213330

  6. Metformin-induced killing of triple-negative breast cancer cells is mediated by reduction in fatty acid synthase via miRNA-193b.

    PubMed

    Wahdan-Alaswad, Reema S; Cochrane, Dawn R; Spoelstra, Nicole S; Howe, Erin N; Edgerton, Susan M; Anderson, Steven M; Thor, Ann D; Richer, Jennifer K

    2014-12-01

    The anti-diabetic drug metformin (1,1-dimethylbiguanide hydrochloride) reduces both the incidence and mortality of several types of cancer. Metformin has been shown to selectively kill cancer stem cells, and triple-negative breast cancer (TNBC) cell lines are more sensitive to the effects of metformin as compared to luminal breast cancer. However, the mechanism underlying the enhanced susceptibility of TNBC to metformin has not been elucidated. Expression profiling of metformin-treated TNBC lines revealed fatty acid synthase (FASN) as one of the genes most significantly downregulated following 24 h of treatment, and a decrease in FASN protein was also observed. Since FASN is critical for de novo fatty acid synthesis and is important for the survival of TNBC, we hypothesized that FASN downregulation facilitates metformin-induced apoptosis. Profiling studies also exposed a rapid metformin-induced increase in miR-193 family members, and miR-193b directly targets the FASN 3'UTR. Addition of exogenous miR-193b mimic to untreated TNBC cells decreased FASN protein expression and increased apoptosis of TNBC cells, while spontaneously immortalized, non-transformed breast epithelial cells remained unaffected. Conversely, antagonizing miR-193 activity impaired the ability of metformin to decrease FASN and cause cell death. Further, the metformin-stimulated increase in miR-193 resulted in reduced mammosphere formation by TNBC lines. These studies provide mechanistic insight into metformin-induced killing of TNBC. PMID:25213330

  7. Metformin impairs Rho GTPase signaling to induce apoptosis in neuroblastoma cells and inhibits growth of tumors in the xenograft mouse model of neuroblastoma

    PubMed Central

    Kumar, Ambrish; Al-Sammarraie, Nadia; DiPette, Donald J.; Singh, Ugra S.

    2014-01-01

    Metformin has been shown to inhibit tumor growth in xenograft rodent models of adult cancers, and various human clinical trials are in progress. However, the precise molecular mechanisms of metformin action are largely unknown. In the present study we examined the anti-tumor activity of metformin against neuroblastoma, and determined the underlying signaling mechanisms. Using human neuroblastoma xenograft mice, we demonstrated that oral administration of metformin (100 and 250 mg/kg body weight) significantly inhibited the growth of tumors. The interference of metformin in spheroid formation further confirmed the anti-tumor activity of metformin. In tumors, the activation of Rac1 (GTP-Rac1) and Cdc42 (GTP-Cdc42) was increased while RhoA activation (GTP-RhoA) was decreased by metformin. It also induced phosphorylation of JNK and inhibited the phosphorylation of ERK1/2 without affecting p38 MAP Kinase. Infection of cells by adenoviruses expressing dominant negative Rac1 (Rac1-N17), Cdc42 (Cdc42-N17) or constitutively active RhoA (RhoA-V14), or incubation of cells with pharmacological inhibitors of Rac1 (NSC23766) or Cdc42 (ML141) significantly protected neuroblastoma cells from metformin-induced apoptosis. Additionally, inhibition of JNK activity along with Rac1 or Cdc42 attenuated cytotoxic effects of metformin. These studies demonstrated that metformin impairs Rho GTPases signaling to induce apoptosis via JNK pathway. PMID:25365944

  8. Metformin Protects H9C2 Cardiomyocytes from High-Glucose and Hypoxia/Reoxygenation Injury via Inhibition of Reactive Oxygen Species Generation and Inflammatory Responses: Role of AMPK and JNK

    PubMed Central

    Hu, Mingyan; Ye, Ping; Liao, Hua; Chen, Manhua

    2016-01-01

    Metformin is a first-line drug for the management of type 2 diabetes. Recent studies suggested cardioprotective effects of metformin against ischemia/reperfusion injury. However, it remains elusive whether metformin provides direct protection against hypoxia/reoxygenation (H/R) injury in cardiomyocytes under normal or hyperglycemic conditions. This study in H9C2 rat cardiomyoblasts was designed to determine cell viability under H/R and high-glucose (HG, 33 mM) conditions and the effects of cotreatment with various concentrations of metformin (0, 1, 5, and 10 mM). We further elucidated molecular mechanisms underlying metformin-induced cytoprotection, especially the possible involvement of AMP-activated protein kinase (AMPK) and Jun NH(2)-terminal kinase (JNK). Results indicated that 5 mM metformin improved cell viability, mitochondrial integrity, and respiratory chain activity under HG and/or H/R (P < 0.05). The beneficial effects were associated with reduced levels of reactive oxygen species generation and proinflammatory cytokines (TNF-α, IL-1α, and IL-6) (P < 0.05). Metformin enhanced phosphorylation level of AMPK and suppressed HG + H/R induced JNK activation. Inhibitor of AMPK (compound C) or activator of JNK (anisomycin) abolished the cytoprotective effects of metformin. In conclusion, our study demonstrated for the first time that metformin possessed direct cytoprotective effects against HG and H/R injury in cardiac cells via signaling mechanisms involving activation of AMPK and concomitant inhibition of JNK. PMID:27294149

  9. Comparison of Antioxidant Effects of Honey, Glibenclamide, Metformin, and Their Combinations in the Kidneys of Streptozotocin-Induced Diabetic Rats

    PubMed Central

    Erejuwa, Omotayo Owomofoyon; Sulaiman, Siti Amrah; Wahab, Mohd Suhaimi Ab; Salam, Sirajudeen Kuttulebbai Nainamohammed; Salleh, Md Salzihan Md; Gurtu, Sunil

    2011-01-01

    Hyperglycemia-induced increase in oxidative stress is implicated in diabetic complications. This study investigated the effect of metformin and/or glibenclamide in combination with honey on antioxidant enzymes and oxidative stress markers in the kidneys of streptozotocin (60 mg/kg; intraperitoneal)-induced diabetic rats. Diabetic rats were randomized into eight groups of five to seven rats and received distilled water (0.5 mL); honey (1.0 g/kg); metformin (100 mg/kg); metformin (100 mg/kg) and honey (1.0 g/kg); glibenclamide (0.6 mg/kg); glibenclamide (0.6 mg/kg) and honey (1.0 g/kg); metformin (100 mg/kg) and glibenclamide (0.6 mg/kg); or metformin (100 mg/kg), glibenclamide (0.6 mg/kg) and honey (1.0 g/kg) orally once daily for four weeks. Malondialdehyde (MDA) levels, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were significantly elevated while catalase (CAT) activity, total antioxidant status (TAS), reduced glutathione (GSH), and GSH:oxidized glutathione (GSSG) ratio was significantly reduced in the diabetic kidneys. CAT, glutathione reductase (GR), TAS, and GSH remained significantly reduced in the diabetic rats treated with metformin and/or glibenclamide. In contrast, metformin or glibenclamide combined with honey significantly increased CAT, GR, TAS, and GSH. These results suggest that combination of honey with metformin or glibenclamide might offer additional antioxidant effect to these drugs. This might reduce oxidative stress-mediated damage in diabetic kidneys. PMID:21340016

  10. Beneficial effects of metformin and irbesartan on advanced glycation end products (AGEs)-RAGE-induced proximal tubular cell injury.

    PubMed

    Ishibashi, Yuji; Matsui, Takanori; Takeuchi, Masayoshi; Yamagishi, Sho-ichi

    2012-03-01

    Advanced glycation end products (AGEs) and their receptor (RAGE) axis contributes to diabetic nephropathy. An oral hypoglycemic agent, metformin may have a potential effect on the inhibition of glycation reactions. Further, since a pathophysiological crosstalk between renin-angiotensin system (RAS) and AGEs-RAGE axis is involved in diabetic nephropathy, it is conceivable that metformin and irbesartan additively could protect against the AGEs-RAGE-induced tubular cell injury. In this study, we addressed the issues. Metformin dose-dependently inhibited the formation of AGEs modification of bovine serum albumin (BSA). Compared with AGEs-modified BSA prepared without metformin (AGEs-MF0), those prepared in the presence of 30 mM or 100 mM metformin (AGEs-MF30 or AGEs-MF100) significantly reduced RAGE mRNA level, reactive oxygen species (ROS) generation, apoptosis, monocyte chemoattractant protein-1 and transforming growth factor-β mRNA level in tubular cells. Irbesartan further inhibited the harmful effects of AGEs-MF0 or AGEs-MF30 on tubular cells. Our present study suggests that combination therapy with metformin and irbesartan may have therapeutic potential in diabetic nephropathy; it could play a protective role against tubular injury in diabetes not only by inhibiting AGEs formation, but also by attenuating the deleterious effects of AGEs via down-regulating RAGE expression and subsequently suppressing ROS generation. PMID:22100460

  11. Oleanolic acid: a novel cardioprotective agent that blunts hyperglycemia-induced contractile dysfunction.

    PubMed

    Mapanga, Rudo F; Rajamani, Uthra; Dlamini, Nonkululeko; Zungu-Edmondson, Makhosazane; Kelly-Laubscher, Roisin; Shafiullah, Mohammed; Wahab, Athiq; Hasan, Mohamed Y; Fahim, Mohamed A; Rondeau, Philippe; Bourdon, Emmanuel; Essop, M Faadiel

    2012-01-01

    Diabetes constitutes a major health challenge. Since cardiovascular complications are common in diabetic patients this will further increase the overall burden of disease. Furthermore, stress-induced hyperglycemia in non-diabetic patients with acute myocardial infarction is associated with higher in-hospital mortality. Previous studies implicate oxidative stress, excessive flux through the hexosamine biosynthetic pathway (HBP) and a dysfunctional ubiquitin-proteasome system (UPS) as potential mediators of this process. Since oleanolic acid (OA; a clove extract) possesses antioxidant properties, we hypothesized that it attenuates acute and chronic hyperglycemia-mediated pathophysiologic molecular events (oxidative stress, apoptosis, HBP, UPS) and thereby improves contractile function in response to ischemia-reperfusion. We employed several experimental systems: 1) H9c2 cardiac myoblasts were exposed to 33 mM glucose for 48 hr vs. controls (5 mM glucose); and subsequently treated with two OA doses (20 and 50 µM) for 6 and 24 hr, respectively; 2) Isolated rat hearts were perfused ex vivo with Krebs-Henseleit buffer containing 33 mM glucose vs. controls (11 mM glucose) for 60 min, followed by 20 min global ischemia and 60 min reperfusion ± OA treatment; 3) In vivo coronary ligations were performed on streptozotocin treated rats ± OA administration during reperfusion; and 4) Effects of long-term OA treatment (2 weeks) on heart function was assessed in streptozotocin-treated rats. Our data demonstrate that OA treatment blunted high glucose-induced oxidative stress and apoptosis in heart cells. OA therapy also resulted in cardioprotection, i.e. for ex vivo and in vivo rat hearts exposed to ischemia-reperfusion under hyperglycemic conditions. In parallel, we found decreased oxidative stress, apoptosis, HBP flux and proteasomal activity following ischemia-reperfusion. Long-term OA treatment also improved heart function in streptozotocin-diabetic rats. These findings are

  12. Cardioprotective effect of methanolic extract of Ixora coccinea Linn. leaves on doxorubicin-induced cardiac toxicity in rats

    PubMed Central

    Momin, Firoz N.; Kalai, Bharatesh R.; Shikalgar, Tabassum S.; Naikwade, Nilofar S.

    2012-01-01

    Objectives: To investigate the effect of methanolic extract of Ixora coccinea Linn. (MEIC) leaves against doxorubicin-induced cardiac toxicity in rats. Material and Methods: Albino Wistar rats were pretreated with the methanolic extract of Ixora coccinea Linn. leaves (200 and 400 mg/kg, orally) for 1 week followed with the simultaneous treatment with doxorubicin (cumulative dose of 15 mg/kg in six divided doses for 2 weeks) along with the extracts for the next 14 days. On the 22nd day hemodynamic parameters such as blood pressure and ECG were recorded. Biochemical study including biomarkers like creatine kinase – MB (CK – MB), lactate dehydrogenase (LDH), SGOT and SGPT, tissue antioxidant markers viz. catalase (CAT), superoxide dismutase (SOD) and extent of lipid peroxidation viz. malondialdehyde (MDA) was estimated. Histopathology of heart was also done to assess the cardioprotective effect. Results: Pretreatment with MEIC significantly reduced (P<0.01) the ST segment elevation and also maintained the BP (P<0.01) close to normal. The MEIC significantly reduced the elevated level of biomarkers like CK - MB, LDH, SGOT, SGPT (P<0.01) near to normal, the MEIC also increased the tissue antioxidant markers viz. CAT, SOD and decreased the level of MDA (P<0.01) in cardiac tissue by dose-dependant manner. The histopathology of heart also further confirmed the cardioprotection provided by the methanolic extract of Ixora coccinea Linn. leaves. Conclusion: The results suggest a cardioprotective effect of Ixora coccinea Linn. leaves due to its antioxidant properties. PMID:22529471

  13. Hyperglycemia-induced metabolic compensation inhibits metformin sensitivity in ovarian cancer

    PubMed Central

    Litchfield, Lacey M.; Mukherjee, Abir; Eckert, Mark A.; Johnson, Alyssa; Mills, Kathryn A.; Pan, Shawn; Shridhar, Viji; Lengyel, Ernst; Romero, Iris L.

    2015-01-01

    Increasing interest in repurposing the diabetic medication metformin for cancer treatment has raised important questions about the translation of promising preclinical findings to therapeutic efficacy, especially in non-diabetic patients. A significant limitation of the findings to date is the use of supraphysiologic metformin doses and hyperglycemic conditions in vitro. Our goals were to determine the impact of hyperglycemia on metformin response and to address the applicability of metformin as a cancer therapeutic in non-diabetic patients. In normoglycemic conditions, lower concentrations of metformin were required to inhibit cell viability, while metformin treatment in hyperglycemic conditions resulted in increased glucose uptake and glycolytic flux, contributing to cell survival. Mechanistically, maintenance of c-Myc expression under conditions of hyperglycemia or via gene amplification facilitated metabolic escape from the effects of metformin. In vivo, treatment of an ovarian cancer mouse model with metformin resulted in greater tumor weight reduction in normoglycemic vs. hyperglycemic mice, with increased c-Myc expression observed in metformin-treated hyperglycemic mice. These findings indicate that hyperglycemia inhibits the anti-cancer effects of metformin in vitro and in vivo. Furthermore, our results suggest that metformin may elicit stronger responses in normoglycemic vs. hyperglycemic patients, highlighting the need for prospective clinical testing in patients without diabetes. PMID:26172303

  14. Metformin exaggerates phenylephrine-induced AMPK phosphorylation independent of CaMKKβ and attenuates contractile response in endothelium-denuded rat aorta

    PubMed Central

    Pyla, Rajkumar; Osman, Islam; Pichavaram, Prahalathan; Hansen, Paul; Segar, Lakshman

    2014-01-01

    Metformin, a widely prescribed antidiabetic drug, has been shown to reduce the risk of cardiovascular disease, including hypertension. Its beneficial effect toward improved vasodilation results from its ability to activate AMPK and enhance nitric oxide formation in the endothelium. To date, metformin regulation of AMPK has not been fully studied in intact arterial smooth muscle, especially during contraction evoked by G protein-coupled receptor (GPCR) agonists. In the present study, ex vivo incubation of endothelium-denuded rat aortic rings with 3 mM metformin for 2 hours resulted in significant accumulation of metformin (~600 pmoles/mg tissue), as revealed by LC-MS/MS MRM analysis. However, metformin did not show significant increase in AMPK phosphorylation under these conditions. Exposure of aortic rings to a GPCR agonist (e.g., phenylephrine) resulted in enhanced AMPK phosphorylation by ~2.5-fold. Importantly, in metformin-treated aortic rings, phenylephrine challenge showed an exaggerated increase in AMPK phosphorylation by ~9.7-fold, which was associated with an increase in AMP/ATP ratio. Pretreatment with compound C (AMPK inhibitor) prevented AMPK phosphorylation induced by phenylephrine alone and also that induced by phenylephrine after metformin treatment. However, pretreatment with STO-609 (CaMKKβ inhibitor) diminished AMPK phosphorylation induced by phenylephrine alone but not that induced by phenylephrine after metformin treatment. Furthermore, attenuation of phenylephrine-induced contraction (observed after metformin treatment) was prevented by AMPK inhibition but not by CaMKKβ inhibition. Together, these findings suggest that, upon endothelial damage in the vessel wall, metformin uptake by the underlying vascular smooth muscle would accentuate AMPK phosphorylation by GPCR agonists independent of CaMKKβ to promote vasorelaxation. PMID:25179145

  15. Novel insights in pathophysiology of antiblastic drugs-induced cardiotoxicity and cardioprotection.

    PubMed

    Deidda, Martino; Madonna, Rosalinda; Mango, Ruggiero; Pagliaro, Pasquale; Bassareo, Pier P; Cugusi, Lucia; Romano, Silvio; Penco, Maria; Romeo, Francesco; Mercuro, Giuseppe

    2016-05-01

    Despite advances in supportive and protective therapy for myocardial function, heart failure caused by various clinical conditions, including cardiomyopathy due to antineoplastic therapy, remains a major cause of morbidity and mortality. Because of the limitations associated with current therapies, investigators have been searching for alternative treatments that can effectively repair the damaged heart and permanently restore its function. Damage to the heart can result from both traditional chemotherapeutic agents, such as anthracyclines, and new targeted therapies, such as trastuzumab. Because of this unresolved issue, investigators are searching for alternative therapeutic strategies. In this article, we present state-of-the-art technology with regard to the genomic and epigenetic mechanisms underlying cardiotoxicity and cardioprotection, the role of anticancer in influencing the redox (reduction/oxidation) balance and the function of stem cells in the repair/regeneration of the adult heart. These findings, although not immediately transferable to clinical applications, form the basis for the development of personalized medicine based on the prevention of cardiotoxicity with the use of genetic testing. Proteomics, metabolomics and investigations on reactive oxygen species-dependent pathways, particularly those that interact with the production of NO and energy metabolism, appear to be promising for the identification of early markers of cardiotoxicity and for the development of cardioprotective agents. Finally, autologous cardiac stem and progenitor cells may represent future contributions in the field of myocardial protection and recovery in the context of antiblastic therapy. PMID:27183528

  16. Metformin Prevents Fatty Liver and Improves Balance of White/Brown Adipose in an Obesity Mouse Model by Inducing FGF21

    PubMed Central

    Kim, Eun Kyung; Lee, Seung Hoon; Jhun, Joo Yeon; Byun, Jae Kyeong; Jeong, Jeong Hee; Lee, Seon-Young; Kim, Jae Kyung; Choi, Jong Young; Cho, Mi-La

    2016-01-01

    Obesity and its associated metabolic disorders are related to the onset of fatty liver and the balance of white adipose tissue (WAT) and brown adipose tissue (BAT). We hypothesized that metformin, an effective pharmacological treatment for type 2 diabetes, would inhibit white adipogenesis, fatty liver, and metabolic dysfunction. Metformin was treated daily for 14 weeks in a high-fat dieting C57BL/6J mice. Serum biomarkers were analyzed and protein level was assessed using confocal staining or flow cytometry. The development of lipid drops in the liver cells and white adipocyte was measured using hematoxylin and eosin or Oil Red O stains. Gene expressions were analyzed with quantitative real-time PCR. Metformin treatment decreased the body weight and improved the metabolic profile of obese mice. In obese mice, metformin also induced the expression of BAT-related markers and increased fibroblast growth factor (FGF) 21 expression in the liver and in white adipocyte. Metformin suppressed white adipocyte differentiation via induction of FGF21. Metformin improves Treg/Th17 balance in CD4+ T cells in mice with high-fat diet-induced obesity. Metformin also improves glucose metabolism and metabolic disorder. Interleukin-17 deficiency also decreases inflammation in mice. Therefore, metformin may be therapeutically useful for the treatment of obesity and metabolic dysfunction. PMID:27057099

  17. Metformin Prevents Fatty Liver and Improves Balance of White/Brown Adipose in an Obesity Mouse Model by Inducing FGF21.

    PubMed

    Kim, Eun Kyung; Lee, Seung Hoon; Jhun, Joo Yeon; Byun, Jae Kyeong; Jeong, Jeong Hee; Lee, Seon-Young; Kim, Jae Kyung; Choi, Jong Young; Cho, Mi-La

    2016-01-01

    Obesity and its associated metabolic disorders are related to the onset of fatty liver and the balance of white adipose tissue (WAT) and brown adipose tissue (BAT). We hypothesized that metformin, an effective pharmacological treatment for type 2 diabetes, would inhibit white adipogenesis, fatty liver, and metabolic dysfunction. Metformin was treated daily for 14 weeks in a high-fat dieting C57BL/6J mice. Serum biomarkers were analyzed and protein level was assessed using confocal staining or flow cytometry. The development of lipid drops in the liver cells and white adipocyte was measured using hematoxylin and eosin or Oil Red O stains. Gene expressions were analyzed with quantitative real-time PCR. Metformin treatment decreased the body weight and improved the metabolic profile of obese mice. In obese mice, metformin also induced the expression of BAT-related markers and increased fibroblast growth factor (FGF) 21 expression in the liver and in white adipocyte. Metformin suppressed white adipocyte differentiation via induction of FGF21. Metformin improves Treg/Th17 balance in CD4+ T cells in mice with high-fat diet-induced obesity. Metformin also improves glucose metabolism and metabolic disorder. Interleukin-17 deficiency also decreases inflammation in mice. Therefore, metformin may be therapeutically useful for the treatment of obesity and metabolic dysfunction. PMID:27057099

  18. Cardioprotective effect of miRNA-22 on hypoxia/reoxygenation induced cardiomyocyte injury in neonatal rats.

    PubMed

    Yang, Jian; Chen, Lihua; Ding, Jiawang; Zhang, Jing; Fan, Zhixing; Yang, Chaojun; Yu, Qinqin; Yang, Jun

    2016-03-15

    MicroRNAs (miRNAs) are implicated in the regulation of pathological and physiological processes in myocardial ischemia/reperfusion (MI/R). Recent studies have revealed that miR-22 might provide a potential cardioprotective effect on ischemic heart disease. However, the mechanism by which miR-22 prevents MI/R is still not fully clear. Here, we investigated the role of miR-22 in hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury. MI/R was simulated in neonatal rat cardiomyocytes with 2h hypoxia followed by 4h reoxygenation. Prior to H/R, cells were transfected by Ad-miR-22 or Ad-scramble. It was revealed that H/R dramatically increased the release of CK and LDH, accompanied by a downregulation of miR-22 expression. Overexpression of miR-22 attenuated cardiomyocyte apoptosis and miR-22 target gene CREB binding protein (CBP) protein level, as determined by flow cytometry analysis and Western blot respectively. We further identified that miR-22 significantly inhibited CBP-related transcriptional factor AP-1 DNA binding activity under H/R. In addition, miR-22 could efficiently change Bcl-2/Bax ratio, and suppress the production of pro-inflammatory cytokines (TNF-α and IL-6) induced by H/R. In conclusion, these results suggest that miR-22 plays an important cardioprotective role partly via regulating CBP/AP-1 pathway to reduce cell apoptosis and inflammatory damage during MI/R injury. PMID:26707060

  19. Moringa oleifera leaf extract prevents isoproterenol-induced myocardial damage in rats: evidence for an antioxidant, antiperoxidative, and cardioprotective intervention.

    PubMed

    Nandave, Mukesh; Ojha, Shreesh Kumar; Joshi, Sujata; Kumari, Santosh; Arya, Dharamvir Singh

    2009-02-01

    The present study evaluated cardioprotective effect of lyophilized hydroalcoholic extract of Moringa oleifera in the isoproterenol (ISP)-induced model of myocardial infarction. Wistar albino male rats were divided into three groups and orally fed saline once daily alone (sham) or with ISP (ISP control) or ISP with M. oleifera (200 mg/kg), respectively, for 1 month. On days 29 and 30 of administration, rats of the ISP control and M. oleifera-ISP groups were administered ISP (85 mg/kg, s.c.) at an interval of 24 hours. On day 31, hemodynamic parameters (mean arterial pressure [MAP], heart rate [HR], left ventricular end-diastolic pressure [LVEDP], and left ventricular peak positive [(+) LV dP/dt] and negative [(-) LV dP/dt] pressures were recorded. At the end of the experiment, the animals were sacrificed, and hearts were excised and processed for biochemical, histopathological, and ultrastructural studies. Chronic treatment with M. oleifera demonstrated mitigating effects on ISP-induced hemodynamic [HR, (+) LV dP/dt, (-) LV dP/dt, and LVEDP] perturbations. Chronic M. oleifera treatment resulted in significant favorable modulation of the biochemical enzymes (superoxide dismutase, catalase, glutathione peroxidase, lactate dehydrogenase, and creatine kinase-MB) but failed to demonstrate any significant effect on reduced glutathione compared to the ISP control group. Moringa treatment significantly prevented the rise in lipid peroxidation in myocardial tissue. Furthermore, M. oleifera also prevented the deleterious histopathological and ultrastructural perturbations caused by ISP. Based on the results of the present study, it can be concluded that M. oleifera extract possesses significant cardioprotective effect, which may be attributed to its antioxidant, antiperoxidative, and myocardial preservative properties. PMID:19298195

  20. Metformin induces apoptosis of human hepatocellular carcinoma HepG2 cells by activating an AMPK/p53/miR-23a/FOXA1 pathway

    PubMed Central

    Sun, Yunpeng; Tao, Chonglin; Huang, Xiaming; He, Han; Shi, Hongqi; Zhang, Qiyu; Wu, Huanhuan

    2016-01-01

    The antidiabetic drug metformin has been shown to possess antitumor functions in many types of cancers. Although studies have revealed its beneficial effects on the prognosis of hepatocellular carcinoma (HCC), the detailed molecular mechanism underlying this event remains largely unknown. In this work, we showed that miR-23a was significantly induced upon metformin treatment; inhibition of miR-23a abrogated the proapoptotic effect of metformin in HepG2 cells. We next established forkhead box protein A1 (FOXA1) as the functional target of miR-23a, and silencing FOXA1 mimicked the effect of metformin. Moreover, the phosphorylation of AMP-activated protein kinase (AMPK) and the expression of p53 were increased upon metformin treatment, and the inhibition of p53 abrogated the induction of miR-23a by metformin, suggesting that AMPK/p53 signaling axis is responsible for the induction of miR-23a by metformin. In summary, we unraveled a novel AMPK/p53/miR-23a/FOXA1 axis in the regulation of apoptosis in HCC, and the application of metformin could, therefore, be effective in the treatment of HCC. PMID:27274280

  1. Sitagliptin, sitagliptin and metformin, or sitagliptin and amitriptyline attenuate streptozotocin-nicotinamide induced diabetic neuropathy in rats

    PubMed Central

    Sharma, Ashish Kumar; Sharma, Akash; Kumari, Rita; Kishore, Kunal; Sharma, Divya; Srinivasan, Bharthu Parthsarthi; Sharma, Ashok; Singh, Santosh Kumar; Gaur, Samir; Jatav, Vijay Singh; Sharma, Prashant; Srivastava, Varnika; Joshi, Sneha; Joshi, Megha; Dhakad, Prashant Kumar; Kanawat, Davender Singh; Mishra, Akanksha; Sharma, Anil; Singh, Dharmendra; Singh, Ravinder Pal; Chawda, Himmat Singh; Singh, Rambir; Raikwar, Sachin Kumar; Kurmi, Muneem Kumar; Khatri, Pankaj; Agarwal, Ashutosh; Munajjam, Arshee

    2012-01-01

    Diabetic neuropathies are a family of nerve disorders caused by diabetes. Symptoms of the disease include nerve palsy, mononeuropathy, mononeuropathy multiplex, diabetic amyotrophy, painful polyneuropathy, autonomic neuropathy, and thoracoabdominal neuropathy. In this study, type 2 diabetes in rats was induced with nicotinamide-streptozotocin. Drug treatment was initiated on the d 15, with the combination regimen of metformin, pioglitazone and glimipiride or metformin and sitagliptin or sitagliptin, amitriptyline and sitagliptin and led to significantly improved glycemic control, increased grip strength and paw jumping response on d 21, 28 and 35 (P < 0.001). Significant increases in blood protein levels and decreases in urinary protein levels were observed in the animals treated with the different regimens on d 21, 28 and 35 (P < 0.001). Combined treatment of streptozotocin and nicotinamide caused marked degeneration of nerve cells, while administration of metformin and sitagliptin showed tissue regeneration and no body weight gain. In conclusion, treatment with sitagliptin and sitagliptin combined with metformin or amitriptyline results in no body weight gain, but causes an increase in grip strength and pain sensitivity, exhibits neural protection, and reverses the alteration of biochemical parameters in rats with streptozotocin-nicotinamide induced type 2 diabetes. PMID:23554750

  2. Involvement of inducible nitric oxide synthase in the loss of cardioprotection by ischemic postconditioning in hypothyroid rats.

    PubMed

    Jeddi, Sajad; Zaman, Jalal; Zadeh-Vakili, Azita; Zarkesh, Maryam; Ghasemi, Asghar

    2016-04-15

    Cardioprotection by ischemic postconditioning (IPost) is negated in hypothyroidism; the underlying mechanisms however are unknown. This study aimed at determining whether changes in Bax, Bcl-2, eNOS, and iNOS gene expressions are involved in the negating effects of IPost against ischemia-reperfusion (IR) injury in hypothyroidism. The hearts from control and hypothyroid rats were perfused in Langendorff apparatus and exposed to 30 min ischemia, followed by 120 min reperfusion and IPost. In a subgroup of hypothyroid rats, ischemia duration was extended to 40 min. Hemodynamic parameters, infarct size, and gene expressions were measured. Compared to controls, hypothyroid rats with 30 min ischemia had higher recovery of post-ischemic LVDP and ± dp/dt, confirmed by decreased CK and LDH levels (187 ± 16 vs. 485 ± 41 and 191 ± 9 vs. 702 ± 48 U/L, respectively; p<0.05), decreased infarct size (6.7 ± 1.1 vs. 46.1 ± 1.7%; p<0.05), and a reduced DNA laddering pattern. Recovery of post-ischemic LVDP and ± dp/dt decreased and infarct size increased following extension of ischemia period in hypothyroid rats. IPost increased eNOS and Bcl-2 expression by 3.2-fold and 3.7-fold and decreased Bax and iNOS expression by 79% and 38%, respectively; it also reduced IR-induced DNA laddering pattern in controls, whereas no change was observed in hypothyroid rats, regardless of the ischemia period. In conclusion, hearts from hypothyroid rats were resistant to IR injury, partly due to the lower expression of iNOS and subsequent reduction in apoptosis after IR. In hypothyroid rats, IPost was not associated with further reduction in iNOS expression and failed to provide additional cardioprotection against ischemia. PMID:26774797

  3. Mildronate, an inhibitor of carnitine biosynthesis, induces an increase in gamma-butyrobetaine contents and cardioprotection in isolated rat heart infarction.

    PubMed

    Liepinsh, Edgars; Vilskersts, Reinis; Loca, Dagnija; Kirjanova, Olga; Pugovichs, Osvalds; Kalvinsh, Ivars; Dambrova, Maija

    2006-12-01

    The inhibition of gamma-butyrobetaine (GBB) hydroxylase, a key enzyme in the biosynthesis of carnitine, contributes to lay ground for the cardioprotective mechanism of action of mildronate. By inhibiting the biosynthesis of carnitine, mildronate is supposed to induce the accumulation of GBB, a substrate of GBB hydroxylase. This study describes the changes in content of carnitine and GBB in rat plasma and heart tissues during long-term (28 days) treatment of mildronate [i.p. (intraperitoneal) 100 mg/kg/daily]. Obtained data show that in concert with a decrease in carnitine concentration, the administration of mildronate caused a significant increase in GBB concentration. We detected about a 5-fold increase in GBB contents in the plasma and brain and a 7-fold increase in the heart. In addition, we tested the cardioprotective effect of mildronate in isolated rat heart infarction model after 3, 7, and 14 days of administration. We found a statistically significant decrease in necrotic area of infarcted rat hearts after 14 days of treatment with mildronate. The cardioprotective effect of mildronate correlated with an increase in GBB contents. In conclusion, our study, for the first time, provides experimental evidence that the long-term administration of mildronate not only decreases free carnitine concentration, but also causes a significant increase in GBB concentration, which correlates with the cardioprotection of mildronate. PMID:17204911

  4. Roles of endothelial nitric oxide synthase (eNOS) and mitochondrial permeability transition pore (MPTP) in epoxyeicosatrienoic acid (EET)-induced cardioprotection against infarction in intact rat hearts.

    PubMed

    Gross, Garrett J; Hsu, Anna; Pfeiffer, Adam W; Nithipatikom, Kasem

    2013-06-01

    We previously demonstrated that 11,12 and 14,15-epoxeicosatrienoic acids (EETs) produce cardioprotection against ischemia-reperfusion injury in dogs and rats. Several signaling mechanisms have been implicated in the cardioprotective actions of the EETs; however, their mechanisms remain largely elusive. Since nitric oxide (NO) plays a significant role in cardioprotection and EETs have been demonstrated to induce NO production in various tissues, we hypothesized that NO is involved in mediating the EET actions in cardioprotection. To test this hypothesis, we used an in vivo rat model of infarction in which intact rat hearts were subjected to 30-min occlusion of the left coronary artery and 2-hr reperfusion. 11,12-EET or 14,15-EET (2.5mg/kg) administered 10min prior to the occlusion reduced infarct size, expressed as a percentage of the AAR (IS/AAR), from 63.9±0.8% (control) to 45.3±1.2% and 45.5±1.7%, respectively. A nonselective nitric oxide synthase (NOS) inhibitor, L-NAME (1.0mg/kg) or a selective endothelial NOS inhibitor, L-NIO (0.30mg/kg) alone did not affect IS/AAR but they completely abolished the cardioprotective effects of the EETs. On the other hand, a selective neuronal NOS inhibitor, nNOS I (0.03mg/kg) and a selective inducible NOS inhibitor, 1400W (0.10mg/kg) did not affect IS/AAR or block the cardioprotective effects of the EETs. Administration of 11,12-EET (2.5mg/kg) to the rats also transiently increased the plasma NO concentration. 14,15-EET (10μM) induced the phosphorylation of eNOS (Ser(1177)) as well as a transient increase of NO production in rat cardiomyoblast cell line (H9c2 cells). When 11,12-EET or 14,15-EET was administered at 5min prior to reperfusion, infarct size was also reduced to 42.8±2.2% and 42.6±1.9%, respectively. Interestingly, L-NAME (1.0mg/kg) and a mitochondrial KATP channel blocker, 5-HD (10mg/kg) did not abolish while a sarcolemmal KATP channel blocker, HMR 1098 (6.0mg/kg) and a mitochondrial permeability transition

  5. Metformin Inhibits Androgen-Induced IGF-IR Up-Regulation in Prostate Cancer Cells by Disrupting Membrane-Initiated Androgen Signaling

    PubMed Central

    Malaguarnera, Roberta; Sacco, Antonella; Morcavallo, Alaide; Squatrito, Sebastiano; Migliaccio, Antimo; Morrione, Andrea; Maggiolini, Marcello

    2014-01-01

    We have previously demonstrated that, in prostate cancer cells, androgens up-regulate IGF-I receptor (IGF-IR) by inducing cAMP-response element-binding protein (CREB) activation and CREB-dependent IGF-IR gene transcription through androgen receptor (AR)-dependent membrane-initiated effects. This IGF-IR up-regulation is not blocked by classical antiandrogens and sensitizes cells to IGF-I-induced biological effects. Metformin exerts complex antitumoral functions in various models and may inhibit CREB activation in hepatocytes. We, therefore, evaluated whether metformin may affect androgen-dependent IGF-IR up-regulation. In the AR+ LNCaP prostate cancer cells, we found that metformin inhibits androgen-induced CRE activity and IGF-IR gene transcription. CRE activity requires the formation of a CREB-CREB binding protein-CREB regulated transcription coactivator 2 (CRTC2) complex, which follows Ser133-CREB phosphorylation. Metformin inhibited Ser133-CREB phosphorylation and induced nuclear exclusion of CREB cofactor CRTC2, thus dissociating the CREB-CREB binding protein-CRTC2 complex and blocking its transcriptional activity. Similarly to metformin action, CRTC2 silencing inhibited IGF-IR promoter activity. Moreover, metformin blocked membrane-initiated signals of AR to the mammalian target of rapamycin/p70S6Kinase pathway by inhibiting AR phosphorylation and its association with c-Src. AMPK signals were also involved to some extent. By inhibiting androgen-dependent IGF-IR up-regulation, metformin reduced IGF-I-mediated proliferation of LNCaP cells. These results indicate that, in prostate cancer cells, metformin inhibits IGF-I-mediated biological effects by disrupting membrane-initiated AR action responsible for IGF-IR up-regulation and suggest that metformin could represent a useful adjunct to the classical antiandrogen therapy. PMID:24437490

  6. Statin and Resveratrol in Combination induces Cardioprotection against Myocardial Infarction in Hypercholesterolemic Rat

    PubMed Central

    Penumathsa, Suresh Varma; Thirunavukkarasu, Mahesh; Koneru, Srikanth; Juhasz, Bela; Zhan, Lijun; Pant, Rima; Menon, Venugopal P; Otani, Hajime; Maulik, Nilanjana

    2007-01-01

    Hypercholesterolemia (HC) is a common health problem that significantly increases risk of cardiovascular disease. Both statin (S) and resveratrol (R) demonstrated cardioprotection through nitric oxide dependent mechanism. Therefore the present study was undertaken to determine whether combination therapy with statin and resveratrol are more cardioprotective than individual treatment groups in ischemic rat heart model. The rats were fed rats with 2% high cholesterol diet and after 8 weeks of high cholesterol diet the animals were treated with statin (1mg/kg bw/day) and resveratrol (20mg/kg bw/day) for 2 weeks. The rats were assigned to: 1) Control (C) 2) HC 3) HCR 4) HCS and 5) HCRS. The hearts, subjected to 30 min global ischemia followed by 120 min reperfusion were used as experimental model. The left ventricular functional recovery (+dp/dt) was found to be significantly better in the HCRS (1926±43), HCR (1556±65) and HCS (1635±40) compared to HC group (1127±16). The infarct size in the HCRS, HCS and HCR groups were 37±3.6, 43±3.3 and 44±4.2 respectively compared to 53±4.6 in HC. The lipid level was found to be decreased in all the treatment groups when compared to HC more significantly in HCS and HCRS groups when compared to HCR. Increased phosphorylation of Akt and eNOS was also observed in all the treatment groups resulting in decreased extent of cardiomyocyte apoptosis but the extent of reduction in apoptosis was more significant in HCRS group compared to all other groups. In-vivo rat myocardial infarction (MI) model subjected to one week of permanent left descending coronary artery (LAD) occlusion documented increased capillary density in HCR and HCRS treated group when compared to HCS treatment group. We also documented increased β-catenin translocation and increased VEGF mRNA expression in all treatment groups. Thus, we conclude that the acute as well as chronic protection afforded by combination treatment with statin and resveratrol may be due to

  7. Improving the preclinical models for the study of chemotherapy-induced cardiotoxicity: a Position Paper of the Italian Working Group on Drug Cardiotoxicity and Cardioprotection.

    PubMed

    Madonna, Rosalinda; Cadeddu, Christian; Deidda, Martino; Mele, Donato; Monte, Ines; Novo, Giuseppina; Pagliaro, Pasquale; Pepe, Alessia; Spallarossa, Paolo; Tocchetti, Carlo Gabriele; Zito, Concetta; Mercuro, Giuseppe

    2015-09-01

    Although treatment for heart failure induced by cancer therapy has improved in recent years, the prevalence of cardiomyopathy due to antineoplastic therapy remains significant worldwide. In addition to traditional mediators of myocardial damage, such as reactive oxygen species, new pathways and target cells should be considered responsible for the impairment of cardiac function during anticancer treatment. Accordingly, there is a need to develop novel therapeutic strategies to protect the heart from pharmacologic injury, and improve clinical outcomes in cancer patients. The development of novel protective therapies requires testing putative therapeutic strategies in appropriate animal models of chemotherapy-induced cardiomyopathy. This Position Paper of the Working Group on Drug Cardiotoxicity and Cardioprotection of the Italian Society of Cardiology aims to: (1) define the distinctive etiopatogenetic features of cardiac toxicity induced by cancer therapy in humans, which include new aspects of mitochondrial function and oxidative stress, neuregulin-1 modulation through the ErbB receptor family, angiogenesis inhibition, and cardiac stem cell depletion and/or dysfunction; (2) review the new, more promising therapeutic strategies for cardioprotection, aimed to increase the survival of patients with severe antineoplastic-induced cardiotoxicity; (3) recommend the distinctive pathological features of cardiotoxicity induced by cancer therapy in humans that should be present in animal models used to identify or to test new cardioprotective therapies. PMID:26168714

  8. Combined metformin and resveratrol confers protection against UVC-induced DNA damage in A549 lung cancer cells via modulation of cell cycle checkpoints and DNA repair.

    PubMed

    Lee, Yong-Syu; Doonan, Barbara B; Wu, Joseph M; Hsieh, Tze-Chen

    2016-06-01

    Aging in humans is a multi-factorial cellular process that is associated with an increase in the risk of numerous diseases including diabetes, coronary heart disease and cancer. Aging is linked to DNA damage, and a persistent source of DNA damage is exposure to ultraviolet (UV) radiation. As such, identifying agents that confer protection against DNA damage is an approach that could reduce the public health burden of age-related disorders. Metformin and resveratrol have both shown effectiveness in preventing several age-related diseases; using human A549 cells, we investigated whether metformin or resveratrol, alone or combined, prevent UVC-induced DNA damage. We found that metformin inhibited UVC-induced upregulation of p53, as well as downregulated the expression of two DNA damage markers: γH2AX and p-chk2. Metformin also upregulated DNA repair as evidenced by the increase in expression of p53R2. Treatment with metformin also induced cell cycle arrest in UVC-induced cells, in correlation with a reduction in the levels of cyclin E/cdk2/Rb and cyclin B1/cdk1. Compared to metformin, resveratrol as a single agent showed less effectiveness in counteracting UVC-elicited cellular responses. However, resveratrol displayed synergism when combined with metformin as shown by the downregulation of p53/γH2AX/p-chk2. In conclusion, the results of the present study validate the effectiveness of metformin, alone or with the addition of resveratrol, in reducing the risk of aging by conferring protection against UV-induced DNA damage. PMID:27109601

  9. Metformin induces apoptosis by microRNA-26a-mediated downregulation of myeloid cell leukaemia-1 in human oral cancer cells.

    PubMed

    Wang, Fang; Xu, Jincheng; Liu, Hao; Liu, Zhe; Xia, Fei

    2016-06-01

    In recent years, population-based studies and retrospective analyses of clinical studies have shown that metformin treatment is associated with reduced cancer incidence and a decrease in cancer‑associated mortality. However, its mechanism of action remains to be fully understood. The present study demonstrates the effects of metformin on KB human oral cancer cells and explores the role of myeloid cell leukaemia‑1 (Mcl‑1) in metformin‑induced mitochondria‑dependent cellular apoptosis. It was demonstrated that metformin exposure caused significant suppression of KB cell proliferation and induced cell death. Furthermore, metformin induced apoptosis through the downregulation of Mcl‑1 in KB human oral cancer cells, and the overexpression of Mcl‑1 in metformin‑treated KB cells significantly increased cell viability. Consistently, Bax and Bim were upregulated in metformin‑treated cells. The results also reveal that microRNA (miR)‑26a expression was markedly increased by metformin. Subsequent to enforced miR‑26a expression in KB cells using miR‑26a mimics, cell viability and the level of Mcl‑1 decreased. These results suggest that the anti‑proliferative effects of metformin in KB cells may result partly from induction of apoptosis by miR-26a-induced downregulation of Mcl-1. PMID:27082123

  10. Bromelain induces cardioprotection against ischemia-reperfusion injury through Akt/FOXO pathway in rat myocardium

    PubMed Central

    Juhasz, Bela; Thirunavukkarasu, Mahesh; Pant, Rima; Zhan, Lijun; Penumathsa, Suresh Varma; Secor, Eric R.; Srivastava, Sapna; Raychaudhuri, Utpal; Menon, Venugopal P.; Otani, Hajime; Thrall, Roger S.; Maulik, Nilanjana

    2008-01-01

    Bromelain (Br), a proteolytic enzyme extracted from the stem of the pineapple, is known to possess anti-inflammatory activity and has been shown to reduce blood viscosity, prevent the aggregation of blood platelets, and improve ischemia-reperfusion (I/R) injury in a skeletal muscle model. We investigated the capacity of Br to limit myocardial injury in a global I/R model. Adult male Sprague-Dawley rats were divided into two groups: control (PBS) and Br at 10 mg/kg in PBS administered via intraperitoneal injection (twice/day) for 15 consecutive days. On day 16, the hearts were excised and subjected to 30 min of global ischemia followed by 2 h of reperfusion. Br treatment showed higher left ventricular functional recovery throughout reperfusion compared with the controls [maximum rate of rise in intraventricular pressure (dP/dtmax), 2,225 vs. 1,578 mmHg/s at 2 h reperfusion]. Aortic flow was also found to be increased in Br treatment when compared with that in untreated rats (11 vs. 1 ml). Furthermore, Br treatment reduced both the infarct size (34% vs. 43%) and the degree of apoptosis (28% vs. 37%) compared with the control animals. Western blot analysis showed an increased phosphorylation of both Akt and FOXO3A in the treatment group compared with the control. These results demonstrated for the first time that Br triggers an Akt-dependent survival pathway in the heart, revealing a novel mechanism of cardioprotective action and a potential therapeutic target against I/R injury. PMID:18192224

  11. Anti-obesity and cardioprotective effects of cinnamic acid in high fat diet- induced obese rats.

    PubMed

    Mnafgui, Kais; Derbali, Amal; Sayadi, Sami; Gharsallah, Neji; Elfeki, Abdelfattah; Allouche, Noureddine

    2015-07-01

    Obesity is a chronic metabolic disorder that is associated with numerous diseases including hyperlipidemia, diabetes mellitus, hypertension, atherosclerosis, cardiovascular disease, and cancer. Cinnamic acid is a phytochemical compound having many biological effects and could be considered for the management of obesity. This study is aimed to assess the possible anti-obesity and cardioprotective properties of cinnamic acid (CA) in high fat diet-fed rats (HFD). Male Wistar rats were divided into 4 groups. They received normal diet, HFD diet, HFD supplemented with fluvastatin (2 mg/kg/day) or cinnamic acid (30 mg/kg/day) for 7 weeks. The results showed an increase in body weight of HFD rats by ~27 % as compared to control group. Moreover, serum lipase activity underwent a significant rise by 103 % which led to an increase in the levels of total cholesterol (T-Ch), triglycerides (TG), LDL-cholesterol in serum of untreated HFD-fed rats. Furthermore, the concentration of leptin and angiotensin-converting enzyme (ACE) activity exhibited remarkable increases in serum of HFD-fed rats as compared to controls. Whereas, the administration of CA to HFD-fed rats improved the body weight gain and serum lipid profile and reverted back near to normal the activities of lipase and ACE. In addition, the echocardiography evidenced that CA is able to protect the aorta and aortic arch and avoided vasoconstriction by increasing their diameters and improved liver steatosis and kidney indices of toxicity. Overall, these results suggest that cinnamic acid exerts anti-obesity and antihypertensive effects through inhibition of lipid digestive enzymes and ACE. PMID:26139902

  12. Metformin-induced metabolic reprogramming of chemoresistant ALDHbright breast cancer cells.

    PubMed

    Cioce, Mario; Valerio, MariaCristina; Casadei, Luca; Pulito, Claudio; Sacconi, Andrea; Mori, Federica; Biagioni, Francesca; Manetti, Cesare; Muti, Paola; Strano, Sabrina; Blandino, Giovanni

    2014-06-30

    Metabolic remodeling is a hallmark of cancer progression and may affect tumor chemoresistance. Here we investigated by 1H-NMR/PCA analysis the metabolic profile of chemoresistant breast cancer cell subpopulations (ALDHbright cells) and their response to metformin, a promising anticancer metabolic modulator. The purified ALDHbright cells exhibited a different metabolic profile as compared to their chemosensitive ALDHlow counterparts. Metformin treatment strongly affected the metabolism of the ALDHbright cells thereby affecting, among the others, the glutathione metabolism, whose upregulation is a feature of progenitor-like, chemoresistant cell subpopulations. Globally, metformin treatment reduced the differences between ALDHbright and ALDHlow cells, making the former more similar to the latter. Metformin broadly modulated microRNAs in the ALDHbright cells, with a large fraction of them predicted to target the same metabolic pathways experimentally identified by 1H-NMR. Additionally, metformin modulated the levels of c-MYC and IRS-2, and this correlated with changes of the microRNA-33a levels. In summary, we observed, both by 1H-NMR and microRNA expression studies, that metformin treatment reduced the differences between the chemoresistant ALDHbright cells and the chemosensitive ALDHlow cells. This works adds on the potential therapeutic relevance of metformin and shows the potential for metabolic reprogramming to modulate cancer chemoresistance. PMID:24980829

  13. Metformin-induced metabolic reprogramming of chemoresistant ALDHbright breast cancer cells

    PubMed Central

    Casadei, Luca; Pulito, Claudio; Sacconi, Andrea; Mori, Federica; Biagioni, Francesca; Manetti, Cesare; Muti, Paola; Strano, Sabrina; Blandino, Giovanni

    2014-01-01

    Metabolic remodeling is a hallmark of cancer progression and may affect tumor chemoresistance. Here we investigated by 1H-NMR/PCA analysis the metabolic profile of chemoresistant breast cancer cell subpopulations (ALDHbright cells) and their response to metformin, a promising anticancer metabolic modulator. The purified ALDHbright cells exhibited a different metabolic profile as compared to their chemosensitive ALDHlow counterparts. Metformin treatment strongly affected the metabolism of the ALDHbright cells thereby affecting, among the others, the glutathione metabolism, whose upregulation is a feature of progenitor-like, chemoresistant cell subpopulations. Globally, metformin treatment reduced the differences between ALDHbright and ALDHlow cells, making the former more similar to the latter. Metformin broadly modulated microRNAs in the ALDHbright cells, with a large fraction of them predicted to target the same metabolic pathways experimentally identified by 1H-NMR. Additionally, metformin modulated the levels of c-MYC and IRS-2, and this correlated with changes of the microRNA-33a levels. In summary, we observed, both by 1H-NMR and microRNA expression studies, that metformin treatment reduced the differences between the chemoresistant ALDHbright cells and the chemosensitive ALDHlow cells. This works adds on the potential therapeutic relevance of metformin and shows the potential for metabolic reprogramming to modulate cancer chemoresistance. PMID:24980829

  14. Metformin lowers the threshold for stress-induced senescence: a role for the microRNA-200 family and miR-205.

    PubMed

    Cufí, Sílvia; Vazquez-Martin, Alejandro; Oliveras-Ferraros, Cristina; Quirantes, Rosa; Segura-Carretero, Antonio; Micol, Vicente; Joven, Jorge; Bosch-Barrera, Joaquim; Del Barco, Sonia; Martin-Castillo, Begoña; Vellon, Luciano; Menendez, Javier A

    2012-03-15

    We have tested the hypothesis that the antidiabetic biguanide metformin can be used to manipulate the threshold for stress-induced senescence (SIS), thus accelerating the onset of cancer-protective cellular senescence in response to oncogenic stimuli. Using senescence-prone murine embryonic fibroblasts (MEFs), we assessed whether metformin treatment modified the senescence phenotype that is activated in response to DNA damaging inducers. Metformin significantly enhanced the number of MEFs entering a senescent stage in response to doxorubicin, an anthracycline that induces cell senescence by activating DNA damage signaling pathways (e.g., ATM/ATR) in a reactive oxygen species (ROS)-dependent manner. Using WI-38 and BJ-1 human diploid fibroblasts (HDFs), we explored whether metformin supplementation throughout their entire replicative lifespan may promote the early appearance of the biomarkers of replicative senescence. Chronic metformin significantly reduced HDFs' lifespan by accelerating both the loss of replicative potential and the acquisition of replicative senescence-related biomarkers (e.g., enlarged and flattened cell shapes, loss of arrayed arrangement, accumulation of intracellular and extracellular debris and SA-β-gal-positive staining). Metformin functioned as a bona fide stressful agent, inducing monotonic, dose-dependent, SIS-like responses in BJ-1 HDFs, which are highly resistant to ROS-induced premature senescence. Metformin-induced SIS in BJ-1 fibroblasts was accompanied by the striking activation of several microRNAs belonging to the miR-200s family (miR-200a, miR-141 and miR429) and miR-205, thus mimicking a recently described ability of ROS to chemosensitize cancer cells by specifically upregulating anti-EMT (epithelial-to-mesenchymal transition) miR-200s. Because the unlimited proliferative potential of stem cells results from their metabolic refractoriness to SIS, we finally tested if metformin treatment could circumvent the stress (e.g., ROS

  15. Quantitative analysis of metformin in antidiabetic tablets by laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Contreras, U.; Ornelas-Soto, N.; Meneses-Nava, M. A.; Barbosa-García, O.; López-de-Alba, P. L.; López-Martínez, L.

    2011-09-01

    Nowadays the production of counterfeit and low quality drugs affects human health and generates losses to pharmaceutical industries and tax revenue losses to government. Currently there are several methods for pharmaceutical product analysis; nevertheless, most of them depend on complex and time consuming steps such as sample preparation. In contrast to conventional methods, Laser-induced breakdown spectroscopy (LIBS) is evaluated as a potential analytical technique for the rapid screening and quality control of anti-diabetic solid formulations. In this paper authors propose a simple method to analyze qualitatively and quantitatively Active Pharmaceutical Ingredients (APIs) such as Metformin hydrochloride. The authors used ten nanosecond duration pulses (FWHM) from a Nd:YAG laser produces the induced breakdown for the analysis. Light is collected and focused into a Cerny-Turner spectrograph and dispersed into an ICCD camera for its detection. We used atomic emissions from Chlorine atoms present only in APIs as analyte signal. The analysis was improved using Bromine as internal standard. Linear calibration curves from synthetic samples were prepared achieving linearity higher than 99%. Our results were compared with HPLC results and validation was performed by statistical methods. The validation analysis suggests that both methods have no significant differences i.e., the proposed method can be implemented for monitoring the pharmaceutical production process in-situ in real time or for inspection and recognition of authenticity.

  16. Metformin and other antidiabetic agents in renal failure patients.

    PubMed

    Lalau, Jean-Daniel; Arnouts, Paul; Sharif, Adnan; De Broe, Marc E

    2015-02-01

    This review mainly focuses on metformin, and considers oral antidiabetic therapy in kidney transplant patients and the potential benefits and risks of antidiabetic agents other than metformin in patients with chronic kidney disease (CKD). In view of the debate concerning lactic acidosis associated with metformin, this review tries to solve a paradox: metformin should be prescribed more widely because of its beneficial effects, but also less widely because of the increasing prevalence of contraindications to metformin, such as reduced renal function. Lactic acidosis appears either as part of a number of clinical syndromes (i.e., unrelated to metformin), induced by metformin (involving an analysis of the drug's pharmacokinetics and mechanisms of action), or associated with metformin (a more complex situation, as lactic acidosis in a metformin-treated patient is not necessarily accompanied by metformin accumulation, nor does metformin accumulation necessarily lead to lactic acidosis). A critical analysis of guidelines and literature data on metformin therapy in patients with CKD is presented. Following the present focus on metformin, new paradoxical issues can be drawn up, in particular: (i) metformin is rarely the sole cause of lactic acidosis; (ii) lactic acidosis in patients receiving metformin therapy is erroneously still considered a single medical entity, as several different scenarios can be defined, with contrasting prognoses. The prognosis for severe lactic acidosis seems even better in metformin-treated patients than in non-metformin users. PMID:24599253

  17. Metformin-Induced Hemolytic Anemia in a Patient With Glucose-6-Phosphate Dehydrogenase Deficiency.

    PubMed

    Ruggiero, Nicole A; Kish, Troy D; Lee, Mikyung L

    2016-01-01

    Metformin, an oral antidiabetic agent, is considered the preferred first-line therapy for patients with type II diabetes. Between 2010 and 2012, it has been estimated that 14 million Americans were administered an oral antidiabetic agent, suggesting the extensive use of metformin among the diabetic population. There have been few case reports implicating metformin in causing hemolytic anemia. We present a case of a 53-year-old white male who developed hemolytic anemia after the initiation of treatment with metformin 500 mg twice daily. The patient experienced a 1.5 g/dL decrease in hemoglobin from baseline and a 2.8 mg/dL increase in total bilirubin within 1 day of treatment. Laboratory results confirmed that the patient was also glucose-6-phosphate dehydrogenase deficient. The hemolytic anemia resolved on discontinuation of metformin. Although this adverse effect seems to be rare, it is important to consider its seriousness. Clinicians should be advised to closely monitor patients newly started on metformin. PMID:25756470

  18. Cardioprotective effect of Vedic Guard against doxorubicin-induced cardiotoxicity in rats: A biochemical, electrocardiographic, and histopathological study

    PubMed Central

    Koti, Basavaraj C.; Nagathan, Shweta; Vishwanathswamy, Agadihiremath; Gadad, Pramod C.; Thippeswamy, Agadihiremath

    2013-01-01

    Background: Vedic Guard is a polyherbal formulation used in the treatment of various ailments, however, is not scientifically assessed for its effect on doxorubicin-induced cardiotoxicity. Objective: To find out the preventive role of Vedic Guard against doxorubicin-induced myocardial toxicity in rats. Materials and Methods: Cardiotoxicity was produced by doxorubicin (15 mg/kg for 2 weeks). Vedic Guard (270 mg/kg, orally) was administered as pre-treatment for 2 weeks and then for 2 weeks alternated with doxorubicin (DXR). The general observations, mortality, histopathology, biomarker like lactate dehydrogenase (LDH), creatine phosphokinase (CPK), aspartate aminotransferase (AST), alanine transaminase (ALT), electrocardiographic (ECG) parameters, antioxidants such as glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) were monitored after 3 weeks of last dose. Results: The repeated administration of DXR causes cardiomyopathy associated with an antioxidant deficit. Pre-treatment with Vedic Guard decreases serum enzyme viz LDH, CPK, AST, and ALT levels to that of normal values. Vedic Guard significantly protected the myocardium from the toxic effect of DXR, by increasing the levels of antioxidants such as GSH, SOD, and CAT and decreased the elevated level of malondialdehyde. The study shows significant alteration of ECG pattern in DXR administered rats. The characteristic findings were elevation of ST segment, reduction in P waves, QRS complex, and R-R interval. Vedic Guard showed a protective effect against DXR-induced altered ECG pattern. It also reduced the severity of cellular damage of the myocardium confirmed by histopathology. Conclusion: The results of the present study indicated cardioprotective effect of Vedic Guard might be attributed to its antioxidant activity. PMID:23772115

  19. Scientific validation of cardioprotective attribute by standardized extract of Bombyx mori against doxorubicin-induced cardiotoxicity in murine model.

    PubMed

    Khan, Masood S; Singh, Mhaveer; Khan, Mohammad A; Arya, D S; Ahmad, Sayeed

    2014-01-01

    Doxorubicin (DOX) is an excellent antineoplastic agent used for the treatment of hematological and solid malignancies. The aqueous extract of Bombyx mori (BMAE) contains amino acids and some flavonoids with obvious cardioprotective effect. The aim of this study was to investigate the possible protective effect of BMAE against DOX-induced cardiotoxicity and its underlying mechanisms on murine model. The metabolic profiling of BMAE was carried out by Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS) and the amino acid profiling by HPLC method using fluorescence detector (HPLC-FLD). The biochemical parameter like caspase-3, tumor necrosis factor-alpha (TNF-α), interleukin -6 (IL-6), creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) and malondialdehyde (MDA) were studied. Tissue damage was further evaluated by histopathological studies. The metabolic profiling of BMAE exhibited presence of quercetin 7-O-ß-D-glucoside, kaempferol 7-O-ß-D-glucopyranoside, coumaric acid glucoside, 2-hydroxy-nonadecanoic acid and 9,12-dihydroxy stearic acid as important constituents. The amino acid profile by HPLC-FLD showed presence of 17 amino acids. The BMAE showed prominent free radical scavenging activity when assessed by the H2O2 and super-oxide method. The results of present investigation showed protection against DOX-induced oxidative stress (lipid peroxidation), by reverting activities of apoptotic markers (caspase-3 and TNF-α), cardiac markers (CK-MB and LDH activities) as well as pro-inflammatory marker IL-6 followed by oral administration of BMAE. In addition, results of histopathology also supported well the above results. It was observed that BMAE protects DOX-induced cardiotoxicity by virtue of its antioxidants possibly by flavonoids and amino acids. PMID:26417320

  20. Cardioprotective Effects of Essential Oil of Lavandula angustifolia on Isoproterenol-induced Acute Myocardial Infarction in Rat

    PubMed Central

    Ziaee, Mojtaba; Khorrami, Arash; Ebrahimi, Maryam; Nourafcan, Hassan; Amiraslanzadeh, Masoumeh; Rameshrad, Maryam; Garjani, Mehraveh; Garjani, Alireza

    2015-01-01

    Myocardial infarction (MI) is a common presentation of the ischemic heart disease. Lavandula angustifolia is an herbaceous plant with antioxidative effects. This study was designed to investigate the cardioprotective effects of lavandula angustifolia essential oil against isoproterenol-induced MI in rats. The dried sample was subjected to hydrodistillation by using a Clevenger and the oils were dried over anhydrous Na2SO4. Male Wistar rats were assigned to 6 groups of control, sham, isoproterenol and treatment with 5, 10, 20 mg/Kg of the essential oil. MI was induced by subcutaneous injection of Isoproterenol (100 mg/Kg) for 3 consecutive days at an interval of 24 h. The essential oil was given intraperitoneally every 24 h started at MI induction. Following anesthesia, hemodynamic parameters were measured. After sacrificing the animals, the hearts were removed to measure the heart to body weight ratio and histopathological examination. Myeloperoxidase (MPO) and Malondialdehyde (MDA) were measured in heart tissues for evaluating the activity of neutrophils and lipid peroxidation, respectively. The essential oil amended ECG pattern by suppressing ST-segment elevation and increasing R-amplitude. 10 mg/Kg of the essential oil significantly decreased heart to body weight ratio (P<0.001) and the elevation of MDA and MPO in myocardium, it also increased dp/dtmax from 2793 ± 210 to 4488 ± 253 mmHg/sec (P<0.001), and 20 mg/Kg of it significantly lowered LVEDP from 14 ± 3.43 to 4.3 ± 0.83 mmHg (P<0.001).The results demonstrated that L. angustifolia protects myocardium against isoproterenol-induced MI that it could be related to its antioxidant properties. PMID:25561934

  1. Cardioprotective Effects of Essential Oil of Lavandula angustifolia on Isoproterenol-induced Acute Myocardial Infarction in Rat.

    PubMed

    Ziaee, Mojtaba; Khorrami, Arash; Ebrahimi, Maryam; Nourafcan, Hassan; Amiraslanzadeh, Masoumeh; Rameshrad, Maryam; Garjani, Mehraveh; Garjani, Alireza

    2015-01-01

    Myocardial infarction (MI) is a common presentation of the ischemic heart disease. Lavandula angustifolia is an herbaceous plant with antioxidative effects. This study was designed to investigate the cardioprotective effects of lavandula angustifolia essential oil against isoproterenol-induced MI in rats. The dried sample was subjected to hydrodistillation by using a Clevenger and the oils were dried over anhydrous Na2SO4. Male Wistar rats were assigned to 6 groups of control, sham, isoproterenol and treatment with 5, 10, 20 mg/Kg of the essential oil. MI was induced by subcutaneous injection of Isoproterenol (100 mg/Kg) for 3 consecutive days at an interval of 24 h. The essential oil was given intraperitoneally every 24 h started at MI induction. Following anesthesia, hemodynamic parameters were measured. After sacrificing the animals, the hearts were removed to measure the heart to body weight ratio and histopathological examination. Myeloperoxidase (MPO) and Malondialdehyde (MDA) were measured in heart tissues for evaluating the activity of neutrophils and lipid peroxidation, respectively. The essential oil amended ECG pattern by suppressing ST-segment elevation and increasing R-amplitude. 10 mg/Kg of the essential oil significantly decreased heart to body weight ratio (P<0.001) and the elevation of MDA and MPO in myocardium, it also increased dp/dtmax from 2793 ± 210 to 4488 ± 253 mmHg/sec (P<0.001), and 20 mg/Kg of it significantly lowered LVEDP from 14 ± 3.43 to 4.3 ± 0.83 mmHg (P<0.001).The results demonstrated that L. angustifolia protects myocardium against isoproterenol-induced MI that it could be related to its antioxidant properties. PMID:25561934

  2. Beneficial effect of zinc chloride and zinc ionophore pyrithione on attenuated cardioprotective potential of preconditioning phenomenon in STZ-induced diabetic rat heart.

    PubMed

    Jamwal, Sumit; Kumar, Kushal; Reddy, B V Krishna

    2016-05-01

    Ischemic preconditioning (IPC) is well demonstrated to produce cardioprotection by phosphorylation and subsequent inactivation of glycogen synthase kinase-3β (GSk-3β) in the normal rat heart, but its effect is attenuated in the diabetic rat heart. This study was designed to investigate the effect of zinc chloride and zinc ionophore pyrithione (ZIP) on the attenuated cardioprotective potential of IPC in the diabetic rat heart. Diabetes mellitus (DM) was induced by a single intraperitoneal administration of streptozotocin (STZ) (50 mg/kg; i.p). The isolated perfused rat heart was subjected to 30 minutes of ischemia followed by 120 minutes of reperfusion. Myocardial infarct size was estimated by triphenyltetrazolium chloride (TTC) staining and cardiac injury was measured by estimating lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) in the coronary effluent. Also, GSK-3β was measured and neutrophil accumulation was measured by estimating myeloperoxidase (MPO) levels. IPC significantly decreased the myocardial infarct size, the release of LDH and CK-MB, the GSK-3β levels and the MPO levels in the normal rat heart. Pre- and post-ischemic treatment with zinc chloride and zinc ionophore pyrithione (ZIP) in the normal and diabetic rat hearts significantly decreased the myocardial infarct size, the level of CK-MB and LDH in the coronary effluent and GSK-3β and MPO levels. Our results suggest that pharmacological preconditioning with zinc chloride and ZIP significantly restored the attenuated cardioprotective potential of IPC in the diabetic rat heart. PMID:26423303

  3. Effect of Metformin and Sitagliptin on Doxorubicin-Induced Cardiotoxicity in Rats: Impact of Oxidative Stress, Inflammation, and Apoptosis.

    PubMed

    Kelleni, Mina Thabet; Amin, Entesar Farghaly; Abdelrahman, Aly Mohamed

    2015-01-01

    Doxorubicin (DOX) is a widely used antineoplastic drug whose efficacy is limited by its cardiotoxicity. The aim of this study was to investigate the possible protective role of the antidiabetic drugs metformin (250 mg/kg dissolved in DW p.o. for seven days) and sitagliptin (10 mg/kg dissolved in DW p.o. for seven days) in a model of DOX-induced (single dose 15 mg/kg i.p. at the fifth day) cardiotoxicity in rats. Results of our study revealed that pretreatment with metformin or sitagliptin produced significant (P < 0.05) cardiac protection manifested by a significant decrease in serum levels of LDH and CK-MB enzymes and cardiac MDA and total nitrites and nitrates levels, a significant increase in cardiac SOD activity, and remarkable improvement in the histopathological features as well as a significant reduction in the immunohistochemical expression of COX-2, iNOS, and caspase-3 enzymes as compared to DOX group. These results may suggest using metformin and/or sitagliptin as preferable drugs for diabetic patients suffering from cancer and receiving DOX in their chemotherapy regimen. PMID:26880912

  4. Effect of Metformin and Sitagliptin on Doxorubicin-Induced Cardiotoxicity in Rats: Impact of Oxidative Stress, Inflammation, and Apoptosis

    PubMed Central

    Kelleni, Mina Thabet; Amin, Entesar Farghaly; Abdelrahman, Aly Mohamed

    2015-01-01

    Doxorubicin (DOX) is a widely used antineoplastic drug whose efficacy is limited by its cardiotoxicity. The aim of this study was to investigate the possible protective role of the antidiabetic drugs metformin (250 mg/kg dissolved in DW p.o. for seven days) and sitagliptin (10 mg/kg dissolved in DW p.o. for seven days) in a model of DOX-induced (single dose 15 mg/kg i.p. at the fifth day) cardiotoxicity in rats. Results of our study revealed that pretreatment with metformin or sitagliptin produced significant (P < 0.05) cardiac protection manifested by a significant decrease in serum levels of LDH and CK-MB enzymes and cardiac MDA and total nitrites and nitrates levels, a significant increase in cardiac SOD activity, and remarkable improvement in the histopathological features as well as a significant reduction in the immunohistochemical expression of COX-2, iNOS, and caspase-3 enzymes as compared to DOX group. These results may suggest using metformin and/or sitagliptin as preferable drugs for diabetic patients suffering from cancer and receiving DOX in their chemotherapy regimen. PMID:26880912

  5. Cardioprotective effect of resveratrol analogue isorhapontigenin versus omega-3 fatty acids in isoproterenol-induced myocardial infarction in rats.

    PubMed

    Abbas, Amr M

    2016-09-01

    Myocardial infarction (MI) is a common cause of mortality worldwide. Isorhapontigenin is a derivative of stilbene with chemical structure similar to resveratrol. The omega-3 fatty acids (FA) have beneficial effects on neurodegenerative, inflammatory, and cardiovascular diseases. The aim of this study was to investigate the effects of pretreatment with isorhapontigenin and omega-3 FA on rat model of isoproterenol-induced MI. Fifty-six rats were divided into seven groups: normal, normal + isorhapontigenin, normal + omega-3 FA, MI, MI + isorhapontigenin, MI + omega-3 FA, and MI + isorhapontigenin + omega-3 FA. Serum levels of cardiac marker enzymes [lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB)], cardiac troponin I (cTnI), inflammatory markers [tumor necrosis factor-alpha (TNF-α) and interleukin-6], and lipid profile [triglycerides, total cholesterol (T.Ch), high and low density lipoproteins (HDL, LDL), and phospholipids] as well as cardiac levels of malondialdehyde and anti-oxidants [reduced glutathione (GSH), superoxide dismutase (SOD), and catalase)] were measured in all rats. ECG and histopathological examination were performed. Isoproterenol caused a significant elevation of ST segment, decreased R wave amplitude, HDL, and anti-oxidants, and increased LDH, CK-MB, cTnI, TNF-α, interleukin-6, malondialdehyde, triglycerides, T.Ch, LDL, and phospholipids. Omega-3 FA or isorhapontigenin significantly decreased the ST segment elevation, LDH, CK-MB, cTnI, TNF-α, interleukin-6, malondialdehyde, and phospholipids and increased R wave amplitude and anti-oxidants. The effects of combined omega-3 FA and isorhapontigenin were more significant than either of them alone. Therefore, we conclude that omega-3 FA and isorhapontigenin have a cardioprotective effect on rats with isoproterenol-induced MI through their anti-oxidant and anti-inflammatory actions. PMID:27193109

  6. Metformin Induces Apoptosis and Downregulates Pyruvate Kinase M2 in Breast Cancer Cells Only When Grown in Nutrient-Poor Conditions

    PubMed Central

    Silvestri, Alessandra; Palumbo, Francesco; Rasi, Ignazio; Posca, Daniela; Pavlidou, Theodora; Paoluzi, Serena; Castagnoli, Luisa; Cesareni, Giovanni

    2015-01-01

    Introduction Metformin is proposed as adjuvant therapy in cancer treatment because of its ability to limit cancer incidence by negatively modulating the PI3K/AKT/mTOR pathway. In vitro, in addition to inhibiting cancer cell proliferation, metformin can also induce apoptosis. The molecular mechanism underlying this second effect is still poorly characterized and published data are often contrasting. We investigated how nutrient availability can modulate metformin-induced apoptosis in three breast cancer cell lines. Material and Methods MCF7, SKBR3 and MDA-MB-231 cells were plated in MEM medium supplemented with increasing glucose concentrations or in DMEM medium and treated with 10 mM metformin. Cell viability was monitored by Trypan Blue assay and treatment effects on Akt/mTOR pathway and on apoptosis were analysed by Western Blot. Moreover, we determined the level of expression of pyruvate kinase M2 (PKM2), a well-known glycolytic enzyme expressed in cancer cells. Results Our results showed that metformin can induce apoptosis in breast cancer cells when cultured at physiological glucose concentrations and that the pro-apoptotic effect was completely abolished when cells were grown in high glucose/high amino acid medium. Induction of apoptosis was found to be dependent on AMPK activation but, at least partially, independent of TORC1 inactivation. Finally, we showed that, in nutrient-poor conditions, metformin was able to modulate the intracellular glycolytic equilibrium by downregulating PKM2 expression and that this mechanism was mediated by AMPK activation. Conclusion We demonstrated that metformin induces breast cancer cell apoptosis and PKM2 downregulation only in nutrient-poor conditions. Not only glucose levels but also amino acid concentration can influence the observed metformin inhibitory effect on the mTOR pathway as well as its pro-apoptotic effect. These data demonstrate that the reduction of nutrient supply in tumors can increase metformin efficacy and

  7. Beneficial effects of combined resveratrol and metformin therapy in treating diet-induced insulin resistance.

    PubMed

    Frendo-Cumbo, Scott; MacPherson, Rebecca E K; Wright, David C

    2016-08-01

    The polyphenol compound resveratrol (RSV) has attracted attention due to its reputed beneficial effects on insulin sensitivity. Our lab has previously identified protective effects of RSV against the development of type 2 diabetes in rats. These effects occurred in a manner similar to thiazolidinedione's (TZDs), a class of insulin sensitizing drugs. TZDs are commonly prescribed in combination with metformin (MET) and thus we sought to examine the combined effects of RSV and MET in treating insulin resistance. Male C57BL6 mice were fed a low- (LFD; 10% Kcal from fat) or high-fat diet (HFD; 60% Kcal from fat) for 9 weeks to induce glucose and insulin intolerance. HFD mice were then assigned to control (HFD), MET (231.28 ± 12.24 mg/kg/day), RSV (93.68 ± 3.51 mg/kg/day), or combined (COM; MET 232.01 ± 17.12 mg/kg/day and RSV 92.77 ± 6.92 mg/kg/day) treatment groups. Changes in glucose and insulin tolerance and tissue-specific insulin signaling were measured 4 weeks post-treatment. RSV or MET alone did not have beneficial effects on glucose tolerance, although MET significantly improved insulin tolerance compared to HFD Glucose and insulin tolerance were significantly improved in COM compared to HFD and this was mirrored by enhanced insulin-stimulated AKT phosphorylation in triceps muscle and inguinal subcutaneous adipose tissue in COM compared to HFD mice. Improvements with COM treatment were not explained by differences in body weight, adiposity, or markers of adipose tissue inflammation. In summary, this study provides evidence of beneficial effects of combined RSV and MET therapy in treating impairments in glucose homeostasis. PMID:27482073

  8. Metformin for treatment of clozapine-induced weight gain in adult patients with schizophrenia: a meta-analysis

    PubMed Central

    LIU, Zhengrong; ZHENG, Wei; GAO, Shuai; QIN, Zhisong; LI, Guannan; NING, Yuping

    2015-01-01

    Background Long-term use of clozapine for individuals with schizophrenia carries a high risk for developing metabolic abnormalities, especially clozapine-induced weight gain. Previous studies suggest that metformin can decrease clozapine-induced weight gain, but the sample sizes of most of these studies are relatively small. Methods We identified randomized controlled trials (RCTs) published prior to December 15, 2015 about the use of metformin to treat clozapine-induced weight gain in adults with schizophrenia by searching several English-language and Chinese-language databases. Two independent researchers did the screening and data extraction. We used Revman 5.3 to conduct the meta-analyses, assessed the risk of bias (RoB), and assessed the strength of the evidence using the Cochrane Grades of Recommendation, Assessment, Development, and Evaluation (GRADE). Results Six studies with a pooled sample of 207 treatment-group patients and 207 control-group patients were included —— three double-blind, placebo-controlled RCTs and three RCTs that did not use placebo controls and were not blinded. The meta-analysis found that compared to the control condition, patients receiving metformin experienced significantly greater reductions in body weight (mean difference [MD]=-2.89 kg, 95% CI: -4.20 to -1.59 kg) and body mass index (BMI) (MD=-0.81, 95% CI: -1.16 to -0.45), but there was no significant difference between the groups in the prevalence of side effects. Based on the GRADE scale, the strength of the evidence for the change in weight outcome was ‘moderate’ and that for the change in BMI outcome was ‘high’, but the strength of evidence about differences in side effects between groups was ‘low’ or ‘very low’. Conclusions Adjunctive treatment with metformin appears to be effective for treating clozapine-induced weight gain and elevations in BMI in adult patients with schizophrenia. However, the quality of the evidence about the safety of this treatment

  9. Cardioprotection from emulsified isoflurane postconditioning is lost in rats with streptozotocin-induced diabetes due to the impairment of Brg1/Nrf2/STAT3 signalling.

    PubMed

    Wang, Yan; Li, Haobo; Huang, Huansen; Liu, Shiming; Mao, Xiaowen; Wang, Sheng; Wong, Stanley Sau-Ching; Xia, Zhengyuan; Irwin, Michael G

    2016-05-01

    Isoflurane postconditioning (IsoPostC) attenuates myocardial ischaemia/reperfusion injury (IRI). Signal transducer and activator of transcription-3 (STAT3) is critical in ischaemic postconditioning cardioprotection, which can be regulated by the Brahma-related gene (Brg1) and nuclear factor-erythroid 2-related factor 2 (Nrf2), although they are both reduced in diabetic hearts. We hypothesized that reduced Brg1/Nrf2 and STAT3 activation may jeopardize IsoPostC-mediated cardioprotection in diabetic hearts. In the present study, Langendorff-perfused, non-diabetic (control) and 8-week-old streptozotocin-induced Type 1 diabetic rat hearts were subjected to 30 min of global ischaemia and 120 min of reperfusion without or with IsoPostC, which was achieved by administering emulsified isoflurane (2.0%, v/v) in Krebs-Henseleit (KH) solution immediately at the onset of reperfusion for 10 min and switching to KH solution perfusion alone thereafter. Cultured H9C2 cells were exposed to normal glucose (NG, 5.5 mM) or high glucose (HG, 30 mM) and subjected to hypoxia/reoxygenation (HR) in the presence or absence of IsoPostC. Diabetic rats displayed larger post-ischaemic myocardial infarction and more severe haemodynamic dysfunction, associated with increased myocardial oxidative stress and reduced cardiac Brg1, Nrf2 and STAT3 phosphorylation/activation (p-STAT3), compared with controls. These changes were reversed/prevented by IsoPostC in control but not in diabetic rats. In H9C2 cells exposed to NG but not HG, IsoPostC significantly attenuated HR-induced cellular injury and superoxide anion production with increased Brg1, Nrf2 and p-STAT3. These beneficial effects of IsoPostC were abolished by Brg1, Nrf2 or STAT3 gene knockdown. Brg1 or Nrf2 gene knockdown abolished IsoPostC-induced STAT3 activation. N-acetylcysteine restored Brg1, Nrf2 and p-STAT3, and IsoPostC-induced protection in H9C2 cells exposed to HG and HR. In conclusion, IsoPostC confers cardioprotection through

  10. Cardioprotective properties of citicoline against hyperthyroidism-induced reperfusion damage in rat hearts.

    PubMed

    Hernández-Esquivel, Luz; Pavón, Natalia; Buelna-Chontal, Mabel; González-Pacheco, Héctor; Belmont, Javier; Chávez, Edmundo

    2015-06-01

    Hyperthyroidism represents an increased risk factor for cardiovascular morbidity, especially when the heart is subjected to an ischemia/reperfusion process. The aim of this study was to explore the possible protective effect of the nucleotide citicoline on the susceptibility of hyperthyroid rat hearts to undergo reperfusion-induced damage, which is associated with mitochondrial dysfunction. Hence, we analyzed the protective effect of citicoline on the electrical behavior and on the mitochondrial function in rat hearts. Hyperthyroidism was established after a daily i.p. injection of triiodothyronine (at 2 mg/kg of body weight) during 5 days. Thereafter, citicoline was administered i.p. (at 125 mg/kg of body weight) for 5 days. In hyperthyroid rat hearts, citicoline protected against reperfusion-induced ventricular arrhythmias. Moreover, citicoline maintained the accumulation of mitochondrial Ca(2+), allowing mitochondria to reach a high transmembrane electric gradient that protected against the release of cytochrome c. It also preserved the activity of the enzyme aconitase that inhibited the release of cytokines. The protection also included the inhibition of oxidative stress-induced mDNA disruption. We conclude that citicoline protects against the reperfusion damage that is found in the hyperthyroid myocardium. This effect might be due to its inhibitory action on the permeability transition in mitochondria. PMID:25589288

  11. Cardioprotective effects of sitagliptin against doxorubicin-induced cardiotoxicity in rats.

    PubMed

    El-Agamy, Dina S; Abo-Haded, Hany M; Elkablawy, Mohamed A

    2016-08-01

    There is a large body of evidence suggesting that inhibitors of dipeptidyl peptidase-4, such as sitagliptin, may exhibit beneficial effects against different inflammatory disorders. This investigation was conducted to elucidate the potential ability of sitagliptin to counteract the injurious effects of doxorubicin in cardiac tissue. Male Wistar rats were pretreated with sitagliptin for 10 days then treated with a single dose of doxorubicin (20 mg/kg, i.p). Electrocardiography, biochemical estimation of serum and tissue markers, and histo- and immunopathological examinations were done. Results have shown that supplementation with sitagliptin resulted in significant improvement of cardiac function with contaminant decrease in serum markers of doxorubicin-induced cardiotoxicity. These results were supported by the histopathological results. Furthermore, a marked protection against oxidative stress was evident through reduction of lipid peroxidation and prevention of reduced glutathione content depletion and superoxide dismutase activity reduction in cardiac tissue of rats pretreated with sitagliptin in combination with doxorubicin. Moreover, sitagliptin ameliorated the activation of nuclear factor kappa-B and the release of inflammatory cytokines, tumour necrosis factor-alpha and nitric oxide. Finally, sitagliptin attenuated doxorubicin-induced increase in the expression of pro-apoptotic protein Bax and in the apoptotic marker, caspase-3. Collectively, these data indicate that sitagliptin pretreatment could alleviate doxorubicin-induced cardiotoxicity via reducing oxidative damage and its subsequent inflammation and apoptosis. PMID:27037281

  12. Biological and biophysics aspects of metformin-induced effects: cortex mitochondrial dysfunction and promotion of toxic amyloid pre-fibrillar aggregates.

    PubMed

    Picone, Pasquale; Vilasi, Silvia; Librizzi, Fabio; Contardi, Marco; Nuzzo, Domenico; Caruana, Luca; Baldassano, Sara; Amato, Antonella; Mulè, Flavia; San Biagio, Pier Luigi; Giacomazza, Daniela; Di Carlo, Marta

    2016-08-01

    The onset of Alzheimer disease (AD) is influenced by several risk factors comprising diabetes. Within this context, antidiabetic drugs, including metformin, are investigated for their effect on AD. We report that in the C57B6/J mice, metformin is delivered to the brain where activates AMP-activated kinase (AMPK), its molecular target. This drug affects the levels of β-secretase (BACE1) and β-amyloid precursor protein (APP), promoting processing and aggregation of β-amyloid (Aβ), mainly in the cortex region. Moreover, metformin induces mitochondrial dysfunction and cell death by affecting the level and conformation of Translocase of the Outer Membrane 40 (TOM40), voltage-dependent anion-selective channels 1 (VDAC1) and hexokinase I (HKI), proteins involved in mitochondrial transport of molecules, including Aβ. By using biophysical techniques we found that metformin is able to directly interact with Aβ influencing its aggregation kinetics and features. These findings indicate that metformin induces different adverse effects, leading to an overall increase of the risk of AD onset. PMID:27509335

  13. Cardioprotective and Antioxidant Influence of Aqueous Extracts from Sesamum indicum Seeds on Oxidative Stress Induced by Cadmium in Wistar Rats

    PubMed Central

    Oyinloye, Babatunji Emmanuel; Ajiboye, Basiru Olaitan; Ojo, Oluwafemi Adeleke; Nwozo, Sarah Onyenibe; Kappo, Abidemi Paul

    2016-01-01

    Background: Oxidative stress has been implicated in the pathogenesis of several acute and chronic diseases of the heart as a result of indiscriminate exposure to cardiotoxic heavy metals. The study reported here was designed to evaluate the possible ameliorative effect of aqueous extracts from Sesamum indicum (SI) seeds on oxidative stress induced by cadmium (Cd) in Wistar rats. Materials and Methods: Daily administration of Cd (200 mg/L Cd as CdCl2) in the animals’ main drinking water for 21 days led to oxidative stress. Thereafter, the ameliorative effects were assessed by measuring biochemical parameters such as extent of lipid peroxidation (LPO), lipid profile, and enzymatic and nonenzymatic antioxidants, as well as serum aminotransferase activities. Results: Treatment with SI extract elicited notable reduction in serum total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels as well as concomitant increase in high-density lipoprotein cholesterol. SI extract also reversed the elevations witnessed in serum aminotransferase activities, LPO level, and ameliorated enzymatic and nonenzymatic antioxidant status in the heart of Cd-exposed rats. Conclusion: Thus, SI appears to be an attractive candidate with potential for the novel treatment of cardiotoxicity and management of oxidative stress arising from Cd exposure. SUMMARY Cadmium (200 mg/L) exposure in drinking water caused pronounced oxidative stress and cardiac tissue damage in animal modelAqueous extract of Sesamum indicum (SI) seeds at a dose of 200 or 400 mg/kg body weight exhibited a significant reversal effect in all biochemical parameters measured such as extent of lipid peroxidation, lipid profile, and enzymatic and nonenzymatic antioxidants, as well as serum aminotransferase activitiesAqueous extract of SI seeds possess antioxidant and cardioprotective potential in a dose-dependent manner, thus conferring protection against oxidative stress induced by cadmium. Abbreviation used

  14. Cardioprotective effect of total paeony glycosides against isoprenaline-induced myocardial ischemia in rats.

    PubMed

    Long, Jiangang; Gao, Meili; Kong, Yu; Shen, Xian; Du, Xiaoyang; Son, Young-Ok; Shi, Xianglin; Liu, Jiankang; Mo, Xiaoyan

    2012-06-15

    Paeoniae radix is a traditional Chinese medicinal herb for treating some diseases; important components are total paeony glycosides (TPGs), an approved drug by the State Food and Drug Administration (SFDA) for the therapy of rheumatoid arthritis (RA). We firstly reported myocardial benefits of TPGs previously, and the present study is to further investigate the underlying mechanisms for preventing oxidative damage in cardiomyopathy. We measured the capacity of TPGs to scavenge free radicals in vitro. Then 60 SD rats were randomly divided into five groups: (1) a normal control group, (2) an isoprenaline (ISO)-induced myocardial ischemic model group, (3) a TPG treatment group (TPGs 269.4 mg/kg delivered by intragastric administration for 3 days before ISO administration and TPGs 449 mg/kg delivered for 3 days after ISO administration), (4) a TPG therapy group (TPGs 449 mg/kg delivered for 3 days after ISO administration), and (5) a positive control group (propranolol 15 mg/kg for 3 days after ISO administration). The ISO-induced myocardial ischemic model was established by subcutaneous injection of 1mg/kg/8h ISO (2 times). The activities of myocardial enzymes, including glutamic oxaloacetic transaminase (GOT), creatine kinase (CK), lactate dehydrogenase (LDH), antioxidant enzyme superoxide dismutase (SOD) as well as the content of lipid peroxidation product malondialdehyde (MDA) were detected. We found that TPGs potently eliminated hydroxyl radicals and superoxide in vitro using ESR assays. Compared with model rats, TPG treatment, TPG therapy and the positive control treatment exhibited significantly reduced activities of GOT, LDH, and CK (p < 0.01), increased activity of SOD (p < 0.01) and lower levels of MDA (p < 0.05). More interestingly, the protective effect of TPG treatment was even better than that of propranolol. These results suggest that TPGs significantly ameliorate ISO-induced myocardial ischemia and their action might be through reducing oxidative stress

  15. Autophagy and protein kinase RNA-like endoplasmic reticulum kinase (PERK)/eukaryotic initiation factor 2 alpha kinase (eIF2α) pathway protect ovarian cancer cells from metformin-induced apoptosis.

    PubMed

    Moon, Hee-Sun; Kim, Boyun; Gwak, HyeRan; Suh, Dong Hoon; Song, Yong Sang

    2016-04-01

    Metformin, an oral biguanide for the treatment of type II diabetes, has been shown to have anticancer effects in ovarian cancer. Energy starvation induced by metformin causes endoplasmic reticulum stress-mediated unfolded protein response (UPR) and autophagy. UPR and autophagy act as a survival or death mechanism in cells. In this study, we observed that metformin-induced apoptosis was relieved by autophagy and the PERK/eIF2α pathway in ovarian cancer cells, but not in peripheral blood mononuclear cells (PBMC) or 'normal' ovarian surface epithelial cells (OSE). Increased PARP cleavage and increased LC3B-II with ATG5-ATG12 complex suggested the induction of apoptosis and autophagy, respectively, in metformin-treated ovarian cancer cells. Accumulation of acidic vacuoles in the cytoplasm and downregulation of p62 further supported late-stage autophagy. Interestingly, metformin induced interdependent activation between autophagy and the UPR, especially the PERK/eIF2α pathway. Inhibition of autophagy-induced PERK inhibition, and vice versa, were demonstrated using small molecular inhibitors (PERK inhibitor I, GSK2606414; autophagy inhibitor, 3-MA, and BafA1). Moreover, autophagy and PERK activation protected ovarian cancer cells against metformin-induced apoptosis. Metformin treatment in the presence of inhibitors of PERK and autophagy, however, had no cytotoxic effects on OSE or PBMC. In conclusion, these results suggest that inhibition of autophagy and PERK can enhance the selective anticancer effects of metformin on ovarian cancer cells. © 2015 Wiley Periodicals, Inc. PMID:25663310

  16. Metformin inhibits 17β-estradiol-induced epithelial-to-mesenchymal transition via βKlotho-related ERK1/2 signaling and AMPKα signaling in endometrial adenocarcinoma cells

    PubMed Central

    Liu, Zhao; Qi, Shasha; Zhao, Xingbo; Li, Mingjiang; Ding, Sentai; Lu, Jiaju; Zhang, Hui

    2016-01-01

    The potential role of metformin in treating endometrial cancer remains to be explored. The current study investigated the role of metformin in 17β-estradiol-induced epithelial-mesenchymal transition (EMT) in endometrial adenocarcinoma cells. We found that 17β-estradiol promoted proliferation and migration, attenuated apoptosis in both estrogen receptor (ER) positive and ER negative endometrial adenocarcinoma cells (Ishikawa and KLE cells, respectively). Metformin abolished 17β-estradiol-induced cell proliferation and reversed 17β-estradiol-induced EMT in Ishikawa cells. In addition, metformin increased the expression of βKlotho, a fibroblast growth factors (FGFs) coreceptor, and decreased ERK1/2 phosphorylation in both Ishikawa and KLE cells. Decreased expression of βKlotho was noted in human endometrial adenocarcinomas, and plasmid-driven expression of βKlotho in Ishikawa cells abolished 17β-estradiol-induced EMT via inhibiting ERK1/2 signaling. βKlotho expression and metformin show synergetic effects on the proliferation and the EMT in Ishikawa cells. Furthermore, we demonstrated that the anti-EMT effects of metformin could be partly abolished by introducing Compound C, a specific AMPKα signaling inhibitor. In conclusion, metformin abolishes 17β-estradiol-induced cell proliferation and EMT in endometrial adenocarcinoma cells by upregulating βKlotho expression, inhibiting ERK1/2 signaling, and activating AMPKα signaling. Our study provides novel mechanistic insight into the anti-tumor effects of metformin. PMID:26824324

  17. Evaluation of cardioprotective effect of aqueous extract of Garcinia indica Linn. fruit rinds on isoprenaline-induced myocardial injury in Wistar albino rats

    PubMed Central

    Patel, Kaksha J.; Panchasara, Ashwin K.; Barvaliya, Manish J.; Purohit, Bhargav M.; Baxi, Seema N.; Vadgama, Vishal K.; Tripathi, C. B.

    2015-01-01

    In the present study, cardioprotective effect of aqueous extract of Garcinia indica Linn. fruit rinds in isoprenaline-induced myocardial infarction in Wistar albino rats was evaluated. In vitro total phenolic, total flavonoid content and 2, 2’-diphenyl-1-picrylhydrazyl hydrate radical scavenging activity was measured. In vivo effect of aqueous extract of G. indica was evaluated in Wistar albino rats by isoprenaline-induced myocardial injury model. Thirty six rats were randomly divided in 6 groups. Rats were treated with G. indica 250 mg/kg and 500 mg/kg doses for 21 days and myocardial injury was produced by subcutaneous injection of isoprenaline 85 mg/kg on day 20 and 21. Carvedilol 1 mg/kg for 21 days served as active control. Electrocardiogram parameters, cardiac injury markers (serum troponin-I, uric acid, lactate dehydrogenase, creatinine kinase-MB, aspartate aminotransferase and alanine aminotransferase), oxidative stress markers (superoxide dismutase, catalase and malondialdehyde level) and histopathological changes were evaluated in each group and compared using appropriate statistical tests. In vitro evaluation of aqueous extract showed significant antioxidant property. Isoprenaline produced significant myocardial ischemia as compared to normal control group (P<0.05). Administration of G. indica in both the doses did not significantly recover the altered electrocardiogram, cardiac injury markers, oxidative stress markers and histopathological myocardial damage as compared to disease control group (P>0.05). The aqueous extract of G. indica was not found to be cardioprotective against myocardial injury. Further study with more sample size and higher dose range may be required to evaluate its cardioprotective effect. PMID:26752987

  18. Evaluation of cardioprotective effect of aqueous extract of Garcinia indica Linn. fruit rinds on isoprenaline-induced myocardial injury in Wistar albino rats.

    PubMed

    Patel, Kaksha J; Panchasara, Ashwin K; Barvaliya, Manish J; Purohit, Bhargav M; Baxi, Seema N; Vadgama, Vishal K; Tripathi, C B

    2015-01-01

    In the present study, cardioprotective effect of aqueous extract of Garcinia indica Linn. fruit rinds in isoprenaline-induced myocardial infarction in Wistar albino rats was evaluated. In vitro total phenolic, total flavonoid content and 2, 2'-diphenyl-1-picrylhydrazyl hydrate radical scavenging activity was measured. In vivo effect of aqueous extract of G. indica was evaluated in Wistar albino rats by isoprenaline-induced myocardial injury model. Thirty six rats were randomly divided in 6 groups. Rats were treated with G. indica 250 mg/kg and 500 mg/kg doses for 21 days and myocardial injury was produced by subcutaneous injection of isoprenaline 85 mg/kg on day 20 and 21. Carvedilol 1 mg/kg for 21 days served as active control. Electrocardiogram parameters, cardiac injury markers (serum troponin-I, uric acid, lactate dehydrogenase, creatinine kinase-MB, aspartate aminotransferase and alanine aminotransferase), oxidative stress markers (superoxide dismutase, catalase and malondialdehyde level) and histopathological changes were evaluated in each group and compared using appropriate statistical tests. In vitro evaluation of aqueous extract showed significant antioxidant property. Isoprenaline produced significant myocardial ischemia as compared to normal control group (P<0.05). Administration of G. indica in both the doses did not significantly recover the altered electrocardiogram, cardiac injury markers, oxidative stress markers and histopathological myocardial damage as compared to disease control group (P>0.05). The aqueous extract of G. indica was not found to be cardioprotective against myocardial injury. Further study with more sample size and higher dose range may be required to evaluate its cardioprotective effect. PMID:26752987

  19. G Protein-Coupled Estrogen Receptor 1 Mediates Acute Estrogen-Induced Cardioprotection via MEK/ERK/GSK-3β Pathway after Ischemia/Reperfusion

    PubMed Central

    Kabir, Mohammad E.; Singh, Harpreet; Lu, Rong; Olde, Bjorn; Leeb-Lundberg, L. M. Fredrik; Bopassa, Jean Chrisostome

    2015-01-01

    Three types of estrogen receptors (ER) exist in the heart, Esr1, Esr2 and the G protein-coupled estrogen receptor 1, Gper1. However, their relative importance in mediating estrogen protective action is unknown. We found that, in the male mouse ventricle, Gper1 transcripts are three- and seventeen-fold more abundant than Esr1 and Esr2 mRNAs, respectively. Analysis of the three ER knockouts (Esr1-/-, Esr2-/- and Gper1-/-) showed that only the Gper1-/- hearts lost their ability to be protected by 40 nM estrogen as measured by heart function, infarct size and mitochondrial Ca2+ overload, an index of mitochondrial permeability transition pore (mPTP) activity. Analysis of Akt, ERK1/2 and GSK-3β salvage kinases uncovered Akt and ERK1/2 transient activation by estrogen whose phosphorylation increased during the first 5 min of non-ischemic perfusion. All these increase in phosphorylation effects were abrogated in Gper1-/-. Inhibition of MEK1/2/ERK1/2 (1 μM U0126) and PI-3K/Akt (10 μM LY294002) signaling showed that the MEK1/2/ERK1/2 pathway via GSK-3β exclusively was responsible for cardioprotection as an addition of U0126 prevented estrogen-induced GSK-3β increased phosphorylation, resistance to mitochondrial Ca2+-overload, functional recovery and protection against infarction. Further, inhibiting PKC translocation (1 μM chelerythrin-chloride) abolished estrogen-induced cardioprotection. These data indicate that estrogen-Gper1 acute coupling plays a key role in cardioprotection against ischemia/reperfusion injury in male mouse via a cascade involving PKC translocation, ERK1/2/GSK-3β phosphorylation leading to the inhibition of the mPTP opening. PMID:26356837

  20. Cardioprotective Activity of Pongamia pinnata in Streptozotocin-Nicotinamide Induced Diabetic Rats

    PubMed Central

    Badole, Sachin L.; Chaudhari, Swapnil M.; Jangam, Ganesh B.; Kandhare, Amit D.; Bodhankar, Subhash L.

    2015-01-01

    Pongamia pinnata (L.) Pierre has been used in traditional medicine for the treatment for diabetes and metabolic disorder. The aim of this study was to investigate the effect of petroleum ether extract of the stem bark of P. pinnata (known as PPSB-PEE) on cardiomyopathy in diabetic rats. Diabetes was induced in overnight fasted Sprague-Dawley rats by using injection of streptozotocin (55 mg/kg, i.p.). Nicotinamide (100 mg/kg, i.p.) was administered 20 min before administration of streptozotocin. Rats were divided into group I: nondiabetic, group II: diabetic control (tween 80, 2%; 10 mL/kg, p.o.) as vehicle, and group III: PPSB-PEE (100 mg/kg, p.o.). The blood glucose level, ECG, hemodynamic parameters, cardiotoxic and antioxidant biomarkers, and histology of heart were carried out after 4 months after STZ with nicotinamide injection. PPSB-PEE treatment improved the electrocardiographic, hemodynamic changes; LV contractile function; biological markers; oxidative stress parameters; and histological changes in STZ induced diabetic rats. PPSB-PEE (100 mg/kg, p.o.) decreased blood glucose level, improved electrocardiographic parameters (QRS, QT, and QTc intervals) and hemodynamic parameters (SBP, DBP, EDP, max dP/dt, contractility index, and heart rate), controlled levels of cardiac biomarkers (CK-MB, LDH, and AST), and improved oxidative stress (SOD, MDA, and GSH) in diabetic rats. PPSB-PEE is a promising remedy against cardiomyopathy in diabetic rats. PMID:25954749

  1. Cardioprotective potential of Punica granatum extract in isoproterenol-induced myocardial infarction in Wistar rats

    PubMed Central

    Mohan, Mahalaxmi; Patankar, Pankaj; Ghadi, Prakash; Kasture, Sanjay

    2010-01-01

    Objective: To determine the protective role of Punica granatum L. (Punicaceae) seed juice extract and its butanolic fraction on heart rate, electrocardiographic patterns, vascular reactivity to catecholamines, cardiac marker enzymes, antioxidant enzymes together with morphologic and histopathological changes in isoproterenol-induced myocardial infarction in male Wistar rats. Materials and Methods: The effects of Punica granatum seed juice extract (100 mg/kg, p.o. and 300 mg/kg, p.o.) and butanolic fraction of Punica granatum seed juice extract (100 mg/kg., p.o.) on cardiac parameters were studied. Isoproterenol hydrochloride was used to induce myocardial infarction in Wistar rats. At the end of the experiment, heart rate, ECG, pressure rate index and cardiac marker enzyme levels were assessed. Results: Rats treated with isoproterenol (85 mg/kg, administered subcutaneously twice at an interval of 24 h) showed a significant increase in heart rate, ST elevation in ECG, pressure rate index and a significant increase in the levels of cardiac marker enzymes- lactate dehydrogenase, and creatine kinase in serum. Isoproterenol significantly reduced superoxide dismutase and catalase activity and increased vascular reactivity to various catecholamines. Pretreatment with PJ (100 mg/kg, p.o. and 300 mg/kg, p.o.) and B-PJ (100 mg/kg., p.o.) for a period of 21 days significantly inhibited the effects of ISO on heart rate, PRI, ECG patterns, levels of LDH, CK, SOD, CAT, and vascular reactivity changes. Treatment with PJ (100 mg/kg and 300 mg/kg) and B-PJ (100 mg/kg., p.o.) alone did not alter any of the parameters as compared to vehicle-treated Wistar rats. Punica granatum-treated animals showed a lesser degree of cellular infiltration in histopathological studies. Conclusion: Punica granatum ameliorates cardiotoxic effects of isoproterenol and may be of value in the treatment of MI. PMID:21808588

  2. Cardioprotective role of leaves extracts of Carissa opaca against CCl4 induced toxicity in rats

    PubMed Central

    2014-01-01

    Background Carissa opaca are used traditionally in Pakistan for the treatment of various human ailments. Therefore, the study is arranged out to assess the cardio protective potential of different fractions of Carissa opaca leaves on CCl4-induced oxidative trauma in kidney. Methods The parameters studied in this respect were the cardiac function test (CK (U/l), CKMB (U/l), genotoxicity (% DNA fragmentation), characteristic morphological findings and antioxidant enzymatic level of cardiac tissue homogenate. Result The protective effects of various fractions of Carissa opaca (C. opaca) leaves extract against CCl4 administration was reviewed by rat cardiac functions alterations. Chronic toxicity caused by eight week treatment of CCl4 to the rats significantly changed the cardiac function test, decreased the activities of antioxidant enzymes and glutathione contents whereas significant increase was found in lipid peroxidation comparative to control group. Administration of various fractions of C. opaca leaves extract with CCl4 showed protective ability against CCl4 intoxication by restoring the cardiac functions alterations, activities of antioxidant enzymes and lipid peroxidation in rat. CCl4 induction in rats also caused DNA fragmentation and histopathalogical abnormalities which were restored by co-admistration of various fraction of C. opaca leaves extract. Conclusion Results revealed that various fraction of C. opaca are helpful in cardiac dysfunctions. PMID:24716654

  3. Cardioprotection by modulation of mitochondrial respiration during ischemia–reperfusion: Role of apoptosis-inducing factor

    SciTech Connect

    Xu, Aijun; Szczepanek, Karol; Hu, Ying; Lesnefsky, Edward J.; Chen, Qun

    2013-06-14

    Highlights: •Blockade of electron transport prevents the loss of AIF from mitochondria during IR. •Blockade of electron transport decreases caspase-independent cell death during IR. •Mitochondrial AIF content is down-regulated in Harlequin mice. •Blockade of electron transport protects Harlequin mouse hearts during IR. •Amobarbital protection is partially dependent on mitochondrial AIF content. -- Abstract: The transient, reversible blockade of electron transport (BET) during ischemia or at the onset of reperfusion protects mitochondria and decreases cardiac injury. Apoptosis inducing factor (AIF) is located within the mitochondrial intermembrane space. A release of AIF from mitochondria into cytosol and nucleus triggers caspase-independent cell death. We asked if BET prevents the loss of AIF from mitochondria as a mechanism of protection in the buffer perfused heart. BET during ischemia with amobarbital, a rapidly reversible inhibitor of mitochondrial complex I, attenuated a release of AIF from mitochondria into cytosol, in turn decreasing the formation of cleaved and activated PARP-1. These results suggest that BET-mediated protection may occur through prevention of the loss of AIF from mitochondria during ischemia–reperfusion. In order to further clarify the role of mitochondrial AIF in BET-mediated protection, Harlequin (Hq) mice, a genetic model with mitochondrial AIF deficiency, were used to test whether BET could still decrease cell injury in Hq mouse hearts during reperfusion. BET during ischemia protected Hq mouse hearts against ischemia–reperfusion injury and improved mitochondrial function in these hearts during reperfusion. Thus, cardiac injury can still be decreased in the presence of down-regulated mitochondrial AIF content. Taken together, BET during ischemia protects both hearts with normal mitochondrial AIF content and hearts with mitochondrial AIF deficiency. Although preservation of mitochondrial AIF content plays a key role in

  4. Modulation of gut microbiota by berberine and metformin during the treatment of high-fat diet-induced obesity in rats.

    PubMed

    Zhang, Xu; Zhao, Yufeng; Xu, Jia; Xue, Zhengsheng; Zhang, Menghui; Pang, Xiaoyan; Zhang, Xiaojun; Zhao, Liping

    2015-01-01

    Accumulating evidence suggests that the gut microbiota is an important factor in mediating the development of obesity-related metabolic disorders, including type 2 diabetes. Metformin and berberine, two clinically effective drugs for treating diabetes, have recently been shown to exert their actions through modulating the gut microbiota. In this study, we demonstrated that metformin and berberine similarly shifted the overall structure of the gut microbiota in rats. Both drugs showed reverting effects on the high-fat diet-induced structural changes of gut microbiota. The diversity of gut microbiota was significantly reduced by both berberine- and metformin-treatments. Nearest shrunken centroids analysis identified 134 operational taxonomic units (OTUs) responding to the treatments, which showed close associations with the changes of obese phenotypes. Sixty out of the 134 OTUs were decreased by both drugs, while those belonging to putative short-chain fatty acids (SCFA)-producing bacteria, including Allobaculum, Bacteriodes, Blautia, Butyricoccus, and Phascolarctobacterium, were markedly increased by both berberine and, to a lesser extent, metformin. Taken together, our findings suggest that berberine and metformin showed similarity in modulating the gut microbiota, including the enrichment of SCFA-producing bacteria and reduction of microbial diversity, which may contribute to their beneficial effects to the host. PMID:26396057

  5. Modulation of gut microbiota by berberine and metformin during the treatment of high-fat diet-induced obesity in rats

    PubMed Central

    Zhang, Xu; Zhao, Yufeng; Xu, Jia; Xue, Zhengsheng; Zhang, Menghui; Pang, Xiaoyan; Zhang, Xiaojun; Zhao, Liping

    2015-01-01

    Accumulating evidence suggests that the gut microbiota is an important factor in mediating the development of obesity-related metabolic disorders, including type 2 diabetes. Metformin and berberine, two clinically effective drugs for treating diabetes, have recently been shown to exert their actions through modulating the gut microbiota. In this study, we demonstrated that metformin and berberine similarly shifted the overall structure of the gut microbiota in rats. Both drugs showed reverting effects on the high-fat diet-induced structural changes of gut microbiota. The diversity of gut microbiota was significantly reduced by both berberine- and metformin-treatments. Nearest shrunken centroids analysis identified 134 operational taxonomic units (OTUs) responding to the treatments, which showed close associations with the changes of obese phenotypes. Sixty out of the 134 OTUs were decreased by both drugs, while those belonging to putative short-chain fatty acids (SCFA)-producing bacteria, including Allobaculum, Bacteriodes, Blautia, Butyricoccus, and Phascolarctobacterium, were markedly increased by both berberine and, to a lesser extent, metformin. Taken together, our findings suggest that berberine and metformin showed similarity in modulating the gut microbiota, including the enrichment of SCFA-producing bacteria and reduction of microbial diversity, which may contribute to their beneficial effects to the host. PMID:26396057

  6. Cardioprotective Effects of Lagenaria siceraria Fruit Juice on Isoproterenol-induced Myocardial Infarction in Wistar Rats: A Biochemical and Histoarchitecture Study

    PubMed Central

    Upaganlawar, A; Balaraman, R

    2011-01-01

    The present study was designed to evaluate the cardioprotective effects of Lagenaria siceraria fruit juice in isoproterenol-induced myocardial infarction. Rats injected with isoproterenol (200 mg/kg, s.c.) showed a significant increase in the levels of serum uric acid, tissue Na++ and Ca++ ions and membrane-bound Ca+2-ATPase activity. A significant decrease in the levels of serum protein, tissue K+ ion, vitamin E level, and the activities of Na+/K+-ATPase and mg+2-ATPase was observed. Isoproterenol injected rats also showed a significant increase in the intensity of lactate dehydrogenase isoenzyme and histopathologic alterations in the heart. Treatment with L. siceraria fruit juice (400 mg/kg/day, p.o.) for 30 days and administration of isoproterenol on 29th and 30th days showed a protective effect on altered biochemical and histopathologic changes. These findings indicate the cardioprotective effect of L. siceraria fruit juice in isoproterenol-induced myocardial infarction in rats. PMID:22224036

  7. [NO-DEPENDENT MECHANISM OF THE CARDIOPROTECTIVE ACTION OF PHENIBUT ON STRESS-INDUCED VIOLATION OF CONTRACTILE FUNCTION OF THE HEART].

    PubMed

    Tyurenkov, I N; Perfilova, V N; Sadikova, N V; Prokofiev, I I

    2015-01-01

    A stressor action for 24 h reduces both ino- and chronotropic reserves of animal heart as evidenced by a decrease in rate growth increments of contraction and relaxation of the myocardium, left ventricular pressure (LVP), heart rate, and the maximum intensity of functioning (MIF) as compared to intact animals during testing for adrenoreactivity and maximum isometric load caused by clamping of the ascending part of the aortic arch. Blockade of NO-synthase leads to a high percentage of animal death during the stressor action, anesthesia, opening of the chest, and functional tests and causes marked reduction in the growth rates of contraction (+dP/dt max) and relaxation (-dP/dt max) speed, LVP, heart rate, and MIF--on the average about 2 times (p < 0.05) under load testing conditions as compared to a control group of stressed animals. Phenibut limits stress-induced violations of the myocardium contractility, as indicated by a higher growth of performance in stress tests--on the average about 1.8 times (p < 0.05) in comparison to the control group of animals. The cardioprotective effect of phenibut is less pronounced when it is introduced on the background of the blockade of NO-ergic system. Under these conditions, there are cases of animal death, predominantly during the stressor action. The results obtained suggest that, for ensuring cardioprotective action of phenibut under conditions of stress-induced myocardial damage, it is necessary to provide for participation of nitric oxide system. PMID:27017698

  8. Metformin induces microRNA-34a to downregulate the Sirt1/Pgc-1α/Nrf2 pathway, leading to increased susceptibility of wild-type p53 cancer cells to oxidative stress and therapeutic agents.

    PubMed

    Do, Minh Truong; Kim, Hyung Gyun; Choi, Jae Ho; Jeong, Hye Gwang

    2014-09-01

    Sirtuin 1 (Sirt1) plays an important role in cellular redox balance and resistance to oxidative stress. Sirt1 exhibits oncogenic properties in wild-type p53 cancer cells, whereas it acts as a tumor suppressor in p53-mutated cancer cells. Here, we investigated the effects of metformin on Sirt1 expression in several cancer cell lines. Using human cancer cell lines that exhibit differential expression of p53, we found that metformin reduced Sirt1 protein levels in cancer cells bearing wild-type p53, but did not affect Sirt1 protein levels in cancer cell lines harboring mutant forms of p53. Metformin-induced p53 protein levels in wild-type p53 cancer cells resulted in upregulation of microRNA (miR)-34a. The use of a miR-34a inhibitor confirmed that metformin-induced miR-34a was required for Sirt1 downregulation. Metformin suppressed peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (Pgc-1α) expression and its downstream target Nrf2 in MCF-7 cells. Genetic tools demonstrated that the reduction of Sirt1 and Pgc-1α by metformin caused Nrf2 downregulation via suppression of PPARγ transcriptional activity. Metformin reduced heme oxygenase-1 and superoxide dismutase 2 but upregulated catalase expression in MCF-7 cells. Metformin-treated MCF-7 cells had no increase in basal levels of reactive oxygen species but were more susceptible to oxidative stress. Furthermore, upregulation of death receptor 5 by metformin-mediated Sirt1 downregulation enhanced the sensitivity of wild-type p53 cancer cells to TRAIL-induced apoptosis. Our results demonstrated that metformin induces miR-34a to suppress the Sirt1/Pgc-1α/Nrf2 pathway and increases susceptibility of wild-type p53 cancer cells to oxidative stress and TRAIL-induced apoptosis. PMID:24970682

  9. Metformin: multi-faceted protection against cancer.

    PubMed

    Del Barco, Sonia; Vazquez-Martin, Alejandro; Cufí, Sílvia; Oliveras-Ferraros, Cristina; Bosch-Barrera, Joaquim; Joven, Jorge; Martin-Castillo, Begoña; Menendez, Javier A

    2011-12-01

    The biguanide metformin, a widely used drug for the treatment of type 2 diabetes, may exert cancer chemopreventive effects by suppressing the transformative and hyperproliferative processes that initiate carcinogenesis. Metformin's molecular targets in cancer cells (e.g., mTOR, HER2) are similar to those currently being used for directed cancer therapy. However, metformin is nontoxic and might be extremely useful for enhancing treatment efficacy of mechanism-based and biologically targeted drugs. Here, we first revisit the epidemiological, preclinical, and clinical evidence from the last 5 years showing that metformin is a promising candidate for oncology therapeutics. Second, the anticancer effects of metformin by both direct (insulin-independent) and indirect (insulin-dependent) mechanisms are discussed in terms of metformin-targeted processes and the ontogenesis of cancer stem cells (CSC), including Epithelial-to-Mesenchymal Transition (EMT) and microRNAs-regulated dedifferentiation of CSCs. Finally, we present preliminary evidence that metformin may regulate cellular senescence, an innate safeguard against cellular immortalization. There are two main lines of evidence that suggest that metformin's primary target is the immortalizing step during tumorigenesis. First, metformin activates intracellular DNA damage response checkpoints. Second, metformin attenuates the anti-senescence effects of the ATP-generating glycolytic metabotype-the Warburg effect-, which is required for self-renewal and proliferation of CSCs. If metformin therapy presents an intrinsic barrier against tumorigenesis by lowering the threshold for stress-induced senescence, metformin therapeutic strategies may be pivotal for therapeutic intervention for cancer. Current and future clinical trials will elucidate whether metformin has the potential to be used in preventive and treatment settings as an adjuvant to current cancer therapeutics. PMID:22203527

  10. Metformin and the ATM DNA damage response (DDR): accelerating the onset of stress-induced senescence to boost protection against cancer.

    PubMed

    Menendez, Javier A; Cufí, Sílvia; Oliveras-Ferraros, Cristina; Martin-Castillo, Begoña; Joven, Jorge; Vellon, Luciano; Vazquez-Martin, Alejandro

    2011-11-01

    By activating the ataxia telangiectasia mutated (ATM)-mediated DNA Damage Response (DDR), the AMPK agonist metformin might sensitize cells against further damage, thus mimicking the precancerous stimulus that induces an intrinsic barrier against carcinogenesis. Herein, we present the new hypothesis that metformin might function as a tissue sweeper of pre-malignant cells before they gain stem cell/tumor initiating properties. Because enhanced glycolysis (the Warburg effect) plays a causal role in the gain of stem-like properties of tumor-initiating cells by protecting them from the pro-senescent effects of mitochondrial respiration-induced oxidative stress, metformin's ability to disrupt the glycolytic metabotype may generate a cellular phenotype that is metabolically protected against immortalization. The bioenergetic crisis imposed by metformin, which may involve enhanced mitochondrial biogenesis and oxidative stress, can lower the threshold for cellular senescence by pre-activating an ATM-dependent pseudo-DDR. This allows an accelerated onset of cellular senescence in response to additional oncogenic stresses. By pushing cancer cells to use oxidative phosphorylation instead of glycolysis, metformin can rescue cell surface major histocompatibility complex class I (MHC-I) expression that is downregulated by oncogenic transformation, a crucial adaptation of tumor cells to avoid the adaptive immune response by cytotoxic T-lymphocytes (CTLs). Aside from restoration of tumor immunosurveillance at the cell-autonomous level, metformin can activate a senescence-associated secretory phenotype (SASP) to reinforce senescence growth arrest, which might trigger an immune-mediated clearance of the senescent cells in a non-cell-autonomous manner. By diminishing the probability of escape from the senescence anti-tumor barrier, the net effect of metformin should be a significant decrease in the accumulation of dysfunctional, pre-malignant cells in tissues, including those with the

  11. Effect of Metformin, Acarbose and Their Combination on the Serum Visfatin Level in Nicotinamide/Streptozocin-Induced Type 2 Diabetic Rats

    PubMed Central

    Salemi, Zahra; Rafie, Elham; Goodarzi, Mohamad Taghi; Ghaffari, Mohamad ali

    2016-01-01

    Background Diabetes mellitus is a chronic metabolic disease with life-threatening complications. Metformin and acarbose are two oral antidiabetic drugs. Objectives This experimental study was designed and carried out at the Arak University of Medical Sciences in Arak, Iran, to investigate the effects of these drugs (both alone and in combination) on glycemic control, lipid profile, and serum visfatin levels in nicotinamide/streptozotocin type 2 diabetic rats. Materials and Methods Type 2 diabetes was induced in 30 male Wistar rats by the administration of streptozotocin (STZ) (60 mg/kg body weight) intraperitoneally (IP) 15 minutes after the IP administration of nicotinamide (110 mg/kg body weight). After one week, the diabetic rats were randomly divided into four groups. Three diabetic groups were treated with 150 mg/kg/day of metformin, acarbose (40 mg/100 g of diet), or a combination of the two for six weeks, respectively. Biochemical parameters, including fasting blood glucose, glycated hemoglobin, lipid profile, insulin, and visfatin were assessed and compared with those of the control diabetic group. Results The data showed metformin, acarbose, and acarbose + metformin downregulated visfatin levels in diabetic rats, but only the reduction in metformin-treated rats was significant (162 ± 21.7, 195.66 ± 6.45 (ng/l), P = 0.001). Fasting blood glucose and glycated hemoglobin decreased significantly in all treated rats, specifically in the treated group that received the two drugs in combination. The serum insulin level was also reduced in all treated groups, and it was significant in the acarbose (P < 0.05) and the combination therapy groups (P < 0.05). The lipid profile improved in all treated groups. Conclusions Compared with acarbose or metformin monotherapy, the addition of acarbose to metformin had superior antihyperglycemia efficacy and provided an efficacious and safe alternative for the treatment of type 2 diabetic rats. Acarbose/metformin reduced the

  12. Effects of addition of a dipeptidyl peptidase IV inhibitor to metformin on sirolimus-induced diabetes mellitus.

    PubMed

    Jin, Long; Lim, Sun Woo; Jin, Jian; Chung, Byung Ha; Yang, Chul Woo

    2016-08-01

    The guideline for the management of new-onset diabetes after transplantation recommends metformin (MET) as a first-line drug, and addition of a second-line drug is needed to better control of hyperglycemia. We tested the effect of addition of a dipeptidyl peptidase IV (DPP IV) inhibitor to MET on sirolimus (SRL)-induced diabetes mellitus (DM). In animal model of SRL-induced DM, MET treatment improved pancreatic islet function (blood glucose level and insulin secretion) and attenuated oxidative stress and apoptotic cell death. Addition of a DPP IV inhibitor to MET improved these parameters more than MET alone. An in vitro study showed that SRL treatment increased pancreas beta cell death and production of reactive oxygen species (ROS), and pretreatment of ROS inhibitor, or p38MAPK inhibitor effectively decreased SRL-induced islet cell death. Exendin-4 (EXD), a substrate of DPP IV or MET significantly improved cell viability and decreased ROS production compared with SRL treatment, and combined treatment with the 2 drugs improved both parameters. At the subcellular level, impaired mitochondrial respiration by SRL were partially improved by MET or EXD and much improved further after addition of EXD to MET. Our data suggest that addition of a DPP IV inhibitor to MET decreases SRL-induced oxidative stress and improves mitochondrial respiration. This finding provides a rationale for the combined use of a DPP IV inhibitor and MET in treating SRL-induced DM. PMID:27059001

  13. Atorvastatin-induced cardioprotection is mediated by increasing inducible nitric oxide synthase and consequent S-nitrosylation of cyclooxygenase-2.

    PubMed

    Atar, Shaul; Ye, Yumei; Lin, Yu; Freeberg, Sheldon Y; Nishi, Shawn P; Rosanio, Salvatore; Huang, Ming-He; Uretsky, Barry F; Perez-Polo, Jose R; Birnbaum, Yochai

    2006-05-01

    We determined the effects of cyclooxygenase-1 (COX-1; SC-560), COX-2 (SC-58125), and inducible nitric oxide synthase (iNOS; 1400W) inhibitors on atorvastatin (ATV)-induced myocardial protection and whether iNOS mediates the ATV-induced increases in COX-2. Sprague-Dawley rats received 10 mg ATV.kg(-1).day(-1) added to drinking water or water alone for 3 days and received intravenous SC-58125, SC-560, 1400W, or vehicle alone. Anesthesia was induced with ketamine and xylazine and maintained with isoflurane. Fifteen minutes after intravenous injection rats underwent 30-min myocardial ischemia followed by 4-h reperfusion [infarct size (IS) protocol], or the hearts were explanted for biochemical analysis and immunoblotting. Left ventricular weight and area at risk (AR) were comparable among groups. ATV reduced IS to 12.7% (SD 3.1) of AR, a reduction of 64% vs. 35.1% (SD 7.6) in the sham-treated group (P < 0.001). SC-58125 and 1400W attenuated the protective effect without affecting IS in the non-ATV-treated rats. ATV increased calcium-independent NOS (iNOS) [11.9 (SD 0.8) vs. 3.9 (SD 0.1) x 1,000 counts/min; P < 0.001] and COX-2 [46.7 (SD 1.1) vs. 6.5 (SD 1.4) pg/ml of 6-keto-PGF(1alpha); P < 0.001] activity. Both SC-58125 and 1400W attenuated this increase. SC-58125 did not affect iNOS activity, whereas 1400W blocked iNOS activity. COX-2 was S-nitrosylated in ATV-treated but not sham-treated rats or rats pretreated with 1400W. COX-2 immunoprecipitated with iNOS but not with endothelial nitric oxide synthase. We conclude that ATV reduced IS by increasing the activity of iNOS and COX-2, iNOS is upstream to COX-2, and iNOS activates COX-2 by S-nitrosylation. These results are consistent with the hypothesis that preconditioning effects are mediated via PG. PMID:16339820

  14. Comparative Study of the Antioxidant Effects of Metformin, Glibenclamide, and Repaglinide in Alloxan-Induced Diabetic Rats

    PubMed Central

    Chukwunonso Obi, Bonaventure; Chinwuba Okoye, Theophine; Okpashi, Victor Eshu; Nonye Igwe, Christiana; Olisah Alumanah, Edwin

    2016-01-01

    Diabetes mellitus is one of the serious global health problems affecting a significant proportion of both developed and developing countries. Overproduction of free radicals and oxidative stress has been associated with the development of diabetic complications. In the present study, the antioxidant effects of metformin (MET), glibenclamide (GLI), and repaglinide (REP) were evaluated in alloxan-induced diabetic rats. The findings from this study may possibly help in understanding the efficacy of these standard drugs in managing the complications arising from diabetes mellitus (DM). Alloxan (130 mg/kg BW) was administered as a single dose to induce diabetes. Four (4) groups of rats (n = 6) were used; group 1 served as diabetic control while groups 2, 3, and 4 were the diabetic test groups that received MET (25 mg/kg), GLI (2.5 mg/kg), and REP (0.5 mg/kg), respectively. The result of the study showed significant (p < 0.05) improvement in the altered antioxidant enzymes (SOD, CAT) and GSH concentration in diabetic treated rats compared with the diabetic control group. MET and REP produced significant effect on the MDA concentration while GLI showed insignificant reduction in the MDA concentration compared with the diabetic control. Findings from this study suggest that the administration of MET, GLI, and REP exerts significant antioxidant effects in alloxan-induced diabetic rats, thus contributing to the protective effect against oxidative stress-induced damage during diabetic complications. PMID:26824037

  15. Comparative Study of the Antioxidant Effects of Metformin, Glibenclamide, and Repaglinide in Alloxan-Induced Diabetic Rats.

    PubMed

    Chukwunonso Obi, Bonaventure; Chinwuba Okoye, Theophine; Okpashi, Victor Eshu; Nonye Igwe, Christiana; Olisah Alumanah, Edwin

    2016-01-01

    Diabetes mellitus is one of the serious global health problems affecting a significant proportion of both developed and developing countries. Overproduction of free radicals and oxidative stress has been associated with the development of diabetic complications. In the present study, the antioxidant effects of metformin (MET), glibenclamide (GLI), and repaglinide (REP) were evaluated in alloxan-induced diabetic rats. The findings from this study may possibly help in understanding the efficacy of these standard drugs in managing the complications arising from diabetes mellitus (DM). Alloxan (130 mg/kg BW) was administered as a single dose to induce diabetes. Four (4) groups of rats (n = 6) were used; group 1 served as diabetic control while groups 2, 3, and 4 were the diabetic test groups that received MET (25 mg/kg), GLI (2.5 mg/kg), and REP (0.5 mg/kg), respectively. The result of the study showed significant (p < 0.05) improvement in the altered antioxidant enzymes (SOD, CAT) and GSH concentration in diabetic treated rats compared with the diabetic control group. MET and REP produced significant effect on the MDA concentration while GLI showed insignificant reduction in the MDA concentration compared with the diabetic control. Findings from this study suggest that the administration of MET, GLI, and REP exerts significant antioxidant effects in alloxan-induced diabetic rats, thus contributing to the protective effect against oxidative stress-induced damage during diabetic complications. PMID:26824037

  16. Neural Mechanisms of Cardioprotection

    PubMed Central

    Gourine, Alexander V.

    2014-01-01

    This review highlights the importance of neural mechanisms capable of protecting the heart against lethal ischemia/reperfusion injury. Increased parasympathetic (vagal) activity limits myocardial infarction, and recent data suggest that activation of autonomic reflex pathways contributes to powerful innate mechanisms of cardioprotection underlying the remote ischemic conditioning phenomena. PMID:24583769

  17. Cardioprotection and thyroid hormones.

    PubMed

    Pingitore, Alessandro; Nicolini, Giuseppina; Kusmic, Claudia; Iervasi, Giorgio; Grigolini, Paolo; Forini, Francesca

    2016-07-01

    The evolution of cardiac disease after an acute ischemic event depends on a complex and dynamic network of mechanisms alternating from ischemic damage due to acute coronary occlusion to reperfusion injury due to the adverse effects of coronary revascularization till post-ischemic remodeling. Cardioprotection is a new purpose of the therapeutic interventions in cardiology with the goal to reduce infarct size and thus prevent the progression toward heart failure after an acute ischemic event. In a complex biological system such as the human one, an effective cardioprotective strategy should diachronically target the network of cross-talking pathways underlying the disease progression. Thyroid system is strictly interconnected with heart homeostasis, and recent studies highlighted its role in cardioprotection, in particular through the preservation of mitochondrial function and morphology, the antifibrotic and proangiogenetic effect and also to the potential induction of cell regeneration and growth. The objective of this review was to highlight the cardioprotective role of triiodothyronine in the complexity of post-ischemic disease evolution. PMID:27011011

  18. Metformin inhibits melanoma development through autophagy and apoptosis mechanisms

    PubMed Central

    Tomic, T; Botton, T; Cerezo, M; Robert, G; Luciano, F; Puissant, A; Gounon, P; Allegra, M; Bertolotto, C; Bereder, J-M; Tartare-Deckert, S; Bahadoran, P; Auberger, P; Ballotti, R; Rocchi, S

    2011-01-01

    Metformin is the most widely used antidiabetic drug because of its proven efficacy and limited secondary effects. Interestingly, recent studies have reported that metformin can block the growth of different tumor types. Here, we show that metformin exerts antiproliferative effects on melanoma cells, whereas normal human melanocytes are resistant to these metformin-induced effects. To better understand the basis of this antiproliferative effect of metformin in melanoma, we characterized the sequence of events underlying metformin action. We showed that 24 h metformin treatment induced a cell cycle arrest in G0/G1 phases, while after 72 h, melanoma cells underwent autophagy as demonstrated by electron microscopy, immunochemistry, and by quantification of the autolysosome-associated LC3 and Beclin1 proteins. In addition, 96 h post metformin treatment we observed robust apoptosis of melanoma cells. Interestingly, inhibition of autophagy by knocking down LC3 or ATG5 decreased the extent of apoptosis, and suppressed the antiproliferative effect of metformin on melanoma cells, suggesting that apoptosis is a consequence of autophagy. The relevance of these observations were confirmed in vivo, as we showed that metformin treatment impaired the melanoma tumor growth in mice, and induced autophagy and apoptosis markers. Taken together, our data suggest that metformin has an important impact on melanoma growth, and may therefore be beneficial in patients with melanoma. PMID:21881601

  19. Radiation-Induced Glycogen Accumulation Detected by Single Cell Raman Spectroscopy Is Associated with Radioresistance that Can Be Reversed by Metformin.

    PubMed

    Matthews, Quinn; Isabelle, Martin; Harder, Samantha J; Smazynski, Julian; Beckham, Wayne; Brolo, Alexandre G; Jirasek, Andrew; Lum, Julian J

    2015-01-01

    Altered cellular metabolism is a hallmark of tumor cells and contributes to a host of properties associated with resistance to radiotherapy. Detection of radiation-induced biochemical changes can reveal unique metabolic pathways affecting radiosensitivity that may serve as attractive therapeutic targets. Using clinically relevant doses of radiation, we performed label-free single cell Raman spectroscopy on a series of human cancer cell lines and detected radiation-induced accumulation of intracellular glycogen. The increase in glycogen post-irradiation was highest in lung (H460) and breast (MCF7) tumor cells compared to prostate (LNCaP) tumor cells. In response to radiation, the appearance of this glycogen signature correlated with radiation resistance. Moreover, the buildup of glycogen was linked to the phosphorylation of GSK-3β, a canonical modulator of cell survival following radiation exposure and a key regulator of glycogen metabolism. When MCF7 cells were irradiated in the presence of the anti-diabetic drug metformin, there was a significant decrease in the amount of radiation-induced glycogen. The suppression of glycogen by metformin following radiation was associated with increased radiosensitivity. In contrast to MCF7 cells, metformin had minimal effects on both the level of glycogen in H460 cells following radiation and radiosensitivity. Our data demonstrate a novel approach of spectral monitoring by Raman spectroscopy to assess changes in the levels of intracellular glycogen as a potential marker and resistance mechanism to radiation therapy. PMID:26280348

  20. Radiation-Induced Glycogen Accumulation Detected by Single Cell Raman Spectroscopy Is Associated with Radioresistance that Can Be Reversed by Metformin

    PubMed Central

    Matthews, Quinn; Isabelle, Martin; Harder, Samantha J.; Smazynski, Julian; Beckham, Wayne; Brolo, Alexandre G.; Jirasek, Andrew; Lum, Julian J.

    2015-01-01

    Altered cellular metabolism is a hallmark of tumor cells and contributes to a host of properties associated with resistance to radiotherapy. Detection of radiation-induced biochemical changes can reveal unique metabolic pathways affecting radiosensitivity that may serve as attractive therapeutic targets. Using clinically relevant doses of radiation, we performed label-free single cell Raman spectroscopy on a series of human cancer cell lines and detected radiation-induced accumulation of intracellular glycogen. The increase in glycogen post-irradiation was highest in lung (H460) and breast (MCF7) tumor cells compared to prostate (LNCaP) tumor cells. In response to radiation, the appearance of this glycogen signature correlated with radiation resistance. Moreover, the buildup of glycogen was linked to the phosphorylation of GSK-3β, a canonical modulator of cell survival following radiation exposure and a key regulator of glycogen metabolism. When MCF7 cells were irradiated in the presence of the anti-diabetic drug metformin, there was a significant decrease in the amount of radiation-induced glycogen. The suppression of glycogen by metformin following radiation was associated with increased radiosensitivity. In contrast to MCF7 cells, metformin had minimal effects on both the level of glycogen in H460 cells following radiation and radiosensitivity. Our data demonstrate a novel approach of spectral monitoring by Raman spectroscopy to assess changes in the levels of intracellular glycogen as a potential marker and resistance mechanism to radiation therapy. PMID:26280348

  1. The status of metformin in Canada.

    PubMed Central

    Lucis, O. J.

    1983-01-01

    During the 1970s two biguanide drugs, phenformin and metformin, were used to control hyperglycemia. Phenformin was phased out of the Canadian market because it carried an unacceptable risk of causing lactic acidosis, but metformin remains available. All documented cases of lactic acidosis associated with metformin administration, which are rare, have occurred abroad in patients who were taking the drug in spite of having contraindications to its use. The two drugs are metabolized differently, phenformin being deactivated and concentrated in the liver, and metformin being excreted rapidly, unchanged, by the kidneys. In properly selected diabetic patients therapeutic doses of metformin do not raise the blood levels of intermediary metabolites enough to induce ketoacidosis or lactic acidosis. The safety of the drug is supported by the clinical experience over about 56,000 patient-years in Canada. PMID:6847752

  2. Metformin suppressed the proliferation of LoVo cells and induced a time-dependent metabolic and transcriptional alteration.

    PubMed

    He, Jiaojiao; Wang, Ke; Zheng, Ningning; Qiu, Yunping; Xie, Guoxiang; Su, Mingming; Jia, Wei; Li, Houkai

    2015-01-01

    Metformin is a widely used anti-diabetic drug with potential anti-tumor activity. However, little is known about its global metabolic and transcriptional impacts on tumor cells. In current study, we performed a metabolic profiling on human-derived colon cancer LoVo cells treated by 10 mM metformin for 8, 24 and 48 h. An obvious time-dependent metabolic alteration was observed from 8 to 48 h, prior to the reduction of cell viability. A total of 47, 45 and 66 differential metabolites were identified between control and metformin-treated cells at three time points. Most of the metabolites were up-regulated at 8 h, but down-regulated at 24 and 48 h by metformin. These metabolites were mainly involved in carbohydrates, lipids, amino acids, vitamins and nucleotides metabolism pathways. Meanwhile, the transcirptomic profile revealed 134 and 3061 differentially expressed genes at 8 and 24 h by metformin. In addition to the cancer signaling pathways, expression of genes involved in cell energy metabolism pathways was significantly altered, which were further validated with genes in glucose metabolism pathway. Altogether, our current data indicate that metformin suppressed the proliferation of LoVo cells, which may be due to the modulation on cell energy metabolism at both metabolic and transcriptional levels in a time-dependent way. PMID:26616174

  3. Metformin suppressed the proliferation of LoVo cells and induced a time-dependent metabolic and transcriptional alteration

    PubMed Central

    He, Jiaojiao; Wang, Ke; Zheng, Ningning; Qiu, Yunping; Xie, Guoxiang; Su, Mingming; Jia, Wei; Li, Houkai

    2015-01-01

    Metformin is a widely used anti-diabetic drug with potential anti-tumor activity. However, little is known about its global metabolic and transcriptional impacts on tumor cells. In current study, we performed a metabolic profiling on human-derived colon cancer LoVo cells treated by 10 mM metformin for 8, 24 and 48 h. An obvious time-dependent metabolic alteration was observed from 8 to 48 h, prior to the reduction of cell viability. A total of 47, 45 and 66 differential metabolites were identified between control and metformin-treated cells at three time points. Most of the metabolites were up-regulated at 8 h, but down-regulated at 24 and 48 h by metformin. These metabolites were mainly involved in carbohydrates, lipids, amino acids, vitamins and nucleotides metabolism pathways. Meanwhile, the transcirptomic profile revealed 134 and 3061 differentially expressed genes at 8 and 24 h by metformin. In addition to the cancer signaling pathways, expression of genes involved in cell energy metabolism pathways was significantly altered, which were further validated with genes in glucose metabolism pathway. Altogether, our current data indicate that metformin suppressed the proliferation of LoVo cells, which may be due to the modulation on cell energy metabolism at both metabolic and transcriptional levels in a time-dependent way. PMID:26616174

  4. Metformin promotes autophagy and apoptosis in esophageal squamous cell carcinoma by downregulating Stat3 signaling

    PubMed Central

    Feng, Y; Ke, C; Tang, Q; Dong, H; Zheng, X; Lin, W; Ke, J; Huang, J; Yeung, S-CJ; Zhang, H

    2014-01-01

    The antidiabetic drug metformin exerts chemopreventive and antineoplastic effects in many types of malignancies. However, the mechanisms responsible for metformin actions appear diverse and may differ in different types of cancer. Understanding the molecular and cellular mechanisms specific for different cancers is important to optimize strategy for metformin treatment in different cancer types. Here, we investigate the in vitro and in vivo effects of metformin on esophageal squamous cell carcinoma (ESCC) cells. Metformin selectively inhibited cell growth in ESCC tumor cells but not immortalized noncancerous esophageal epithelial cells. In addition to apoptosis, metformin triggered autophagy. Pharmacological or genetic inhibition of autophagy sensitized ESCC cells to metformin-induced apoptotic cell death. Mechanistically, signal transducer and activator of transcription 3 (Stat3) and its downstream target Bcl-2 was inactivated by metformin treatment. Accordingly, small interfering RNA (siRNA)-mediated Stat3 knockdown enhanced metformin-induced autophagy and apoptosis, and concomitantly enhanced the inhibitory effect of metformin on cell viability. Similarly, the Bcl-2 proto-oncogene, an inhibitor of both apoptosis and autophagy, was repressed by metformin. Ectopic expression of Bcl-2 protected cells from metformin-mediated autophagy and apoptosis. In vivo, metformin downregulated Stat3 activity and Bcl-2 expression, induced apoptosis and autophagy, and inhibited tumor growth. Together, inactivation of Stat3-Bcl-2 pathway contributes to metformin-induced growth inhibition of ESCC by facilitating crosstalk between apoptosis and autophagy. PMID:24577086

  5. Metformin attenuates olanzapine-induced hepatic, but not peripheral insulin resistance.

    PubMed

    Remington, Gary J; Teo, Celine; Wilson, Virginia; Chintoh, Araba; Guenette, Melanie; Ahsan, Zohra; Giacca, Adria; Hahn, Margaret K

    2015-11-01

    Antipsychotics (APs) are linked to diabetes, even without weight gain. Whether anti-diabetic drugs are efficacious in reversing the direct effects of APs on glucose pathways is largely undetermined. We tested two metformin (Met) doses to prevent impairments seen following a dose of olanzapine (Ola) (3 mg/kg); glucokinetics were measured using the hyperinsulinemic-euglycemic clamp (HIEC). Met (150 mg/kg; n=13, or 400 mg/kg; n=11) or vehicle (Veh) (n=11) was administered through gavage preceding an overnight fast, followed by a second dose prior to the HIEC. Eleven additional animals were gavaged with Veh and received a Veh injection during the HIEC (Veh/Veh); all others received Ola. Basal glucose was similar across treatment groups. The Met 400 group had significantly greater glucose appearance (Ra) in the basal period (i.e., before Ola, or hyperinsulinemia) vs other groups. During hyperinsulinemia, glucose infusion rate (GINF) to maintain euglycemia (reflective of whole-body insulin sensitivity) was higher in Veh/Veh vs other groups. Met 150/Ola animals demonstrated increased GINF relative to Veh/Ola during early time points of the HIEC. Glucose utilization during hyperinsulinemia, relative to basal conditions, was significantly higher in Veh/Veh vs other groups. The change in hepatic glucose production (HGP) from basal to hyperinsulinemia demonstrated significantly greater decreases in Veh/Veh and Met 150/Ola groups vs Veh/Ola. Given the increase in basal Ra with Met 400, we measured serum lactate (substrate for HGP), finding increased levels in Met 400 vs Veh and Met 150. In conclusion, Met attenuates hepatic insulin resistance observed with acute Ola administration, but fails to improve peripheral insulin resistance. Use of supra-therapeutic doses of Met may mask metabolic benefits by increasing lactate. PMID:26330531

  6. Phytochemical screening and evaluation of cardioprotective activity of ethanolic extract of Ocimum basilicum L. (basil) against isoproterenol induced myocardial infarction in rats

    PubMed Central

    2012-01-01

    Background and the purpose of the study The objectives of the present study were phytochemical screening and study of the effects of ethanolic extract of aerial parts of Ocimum basilicum (basil) on cardiac functions and histopathological changes in isoproterenol-induced myocardial infarction (MI). Methods The leaves of the plant were extracted with ethanol by maceration and subjected to colorimetry to determine flavonoids and phenolic compounds. High-performance TLC analysis and subsequent CAMAG's TLC scanning were performed to quantify rosmarinic acid content. Wistar rats were assigned to 6 groups of normal control, sham, isoproterenol, and treatment with 10, 20, and 40 mg/kg of the extract two times per day concurrent with MI induction. A subcutaneous injection of isoproterenol (100 mg/kg/day) for 2 consecutive days was used to induce MI. Results Phytochemical screening indicated the presence of phenolic compounds (5.36%) and flavonoids (1.86%). Rosmarinic acid was the principal phenolic compound with a 15.74% existence. The ST-segment elevation induced by isoproterenol was significantly suppressed by all doses of the extract. A severe myocardial necrosis and fibrosis with a sharp reduction in left ventricular contractility and a marked increase in left ventricular end-diastolic pressure were seen in the isoproterenol group, all of which were significantly improved by the extract treatment. In addition to in-vitro antioxidant activity, the extract significantly suppressed the elevation of malondialdehyde levels both in the serum and the myocardium. Conclusion The results of the study demonstrate that Ocimum basilicum strongly protected the myocardium against isoproterenol-induced infarction and suggest that the cardioprotective effects could be related to antioxidative activities. PMID:23351503

  7. Maladaptive Modulations of NLRP3 Inflammasome and Cardioprotective Pathways Are Involved in Diet-Induced Exacerbation of Myocardial Ischemia/Reperfusion Injury in Mice

    PubMed Central

    Penna, Claudia; Nigro, Debora; Chiazza, Fausto; Fracasso, Veronica; Tullio, Francesca; Aragno, Manuela

    2016-01-01

    Excessive fatty acids and sugars intake is known to affect the development of cardiovascular diseases, including myocardial infarction. However, the underlying mechanisms are ill defined. Here we investigated the balance between prosurvival and detrimental pathways within the heart of C57Bl/6 male mice fed a standard diet (SD) or a high-fat high-fructose diet (HFHF) for 12 weeks and exposed to cardiac ex vivo ischemia/reperfusion (IR) injury. Dietary manipulation evokes a maladaptive response in heart mice, as demonstrated by the shift of myosin heavy chain isoform content from α to β, the increased expression of the Nlrp3 inflammasome and markers of oxidative metabolism, and the downregulation of the hypoxia inducible factor- (HIF-)2α and members of the Reperfusion Injury Salvage Kinases (RISK) pathway. When exposed to IR, HFHF mice hearts showed greater infarct size and lactic dehydrogenase release in comparison with SD mice. These effects were associated with an exacerbated overexpression of Nlrp3 inflammasome, resulting in marked caspase-1 activation and a compromised activation of the cardioprotective RISK/HIF-2α pathways. The common mechanisms of damage here reported lead to a better understanding of the cross-talk among prosurvival and detrimental pathways leading to the development of cardiovascular disorders associated with metabolic diseases. PMID:26788246

  8. Metformin decreases glucose oxidation and increases the dependency of prostate cancer cells on reductive glutamine metabolism

    PubMed Central

    Fendt, Sarah-Maria; Bell, Eric L.; Keibler, Mark A.; Davidson, Shawn M.; Wirth, Gregory J.; Fiske, Brian; Mayers, Jared R.; Schwab, Matthias; Bellinger, Gary; Csibi, Alfredo; Patnaik, Akash; Jose Blouin, Marie; Cantley, Lewis C.; Guarente, Leonard; Blenis, John; Pollak, Michael N.; Olumi, Aria F.

    2013-01-01

    Metformin inhibits cancer cell proliferation and epidemiology studies suggest an association with increased survival in cancer patients taking metformin, however, the mechanism by which metformin improves cancer outcomes remains controversial. To explore how metformin might directly affect cancer cells, we analyzed how metformin altered the metabolism of prostate cancer cells and tumors. We found that metformin decreased glucose oxidation and increased dependency on reductive glutamine metabolism in both cancer cell lines and in a mouse model of prostate cancer. Inhibition of glutamine anaplerosis in the presence of metformin further attenuated proliferation while increasing glutamine metabolism rescued the proliferative defect induced by metformin. These data suggest that interfering with glutamine may synergize with metformin to improve outcomes in patients with prostate cancer. PMID:23687346

  9. Effects of metformin plus gliclazide versus metformin plus glimepiride on cardiovascular risk factors in patients with type 2 diabetes mellitus.

    PubMed

    Hassan, Memy Hegazy; Abd-Allah, Gamil Mohamed

    2015-09-01

    High blood glucose level, lipid profile disturbances and plasma homocysteine (Hcy) are important risk factors for cardiovascular diseases in patients with type 2 diabetes. This study was conducted to evaluate and compare effects of glimepiride/metformin combination versus gliclazide/metformin combination on cardiovascular risk factors in type-2 diabetes mellitus (T2DM) patients. One hundred and eighty T2DM patients were randomly allocated for treatment with placebo (control), metformin (500 mg twice daily), glimepiride (3mg once daily), gliclazide (80 mg once daily), metformin plus glimepiride or metformin plus gliclazide for 3 months. We evaluated plasma levels of glucose (PG), glycated hemoglobin (HbA1C), Hcy, vitamin B12, folic acid and lipid profile before treatment and 3 months post treatment. Compared to metformin treated patients, glimepiride plus metformin induced significant reductions in: fasting plasma glucose, postprandial PG level, HbA1C % and Hcy level. Conversely, plasma folic acid and vitamin B12 were significantly increased. The levels of total cholesterol and triglyceride were significantly decreased; low-density lipoprotein was markedly decreased, whereas high-density lipoprotein was significantly increased and hence risk ratio was significantly decreased. Similar results but with lower values were obtained using combination of metformin plus gliclazide on glycemic control only. Combination of glimepiride with metformin was superior to gliclazide plus metformin in alleviating the cardiovascular risk factors in type 2 diabetes mellitus patients. PMID:26408873

  10. Metformin: a new option in cancer treatment.

    PubMed

    Belda-Iniesta, Cristóbal; Pernía, Olga; Simó, Rafael

    2011-06-01

    Metformin is a biguanine, the most widely used antidiabetic drug for the treatment of type 2 diabetes. Some studies suggest that metformin decreases the incidence of cancer and cancer-related mortality in diabetic patients. Metformin activates the AMP-activated protein kinase (AMPK) pathway, a major sensor of the energy status of the cell and an inhibitor of mammalian target of rapamycin (mTOR) catalytic activity, inducing a decrease in blood glucose by decreasing hepatic gluconeogenesis and stimulating glucose uptake in the muscle. Some preclinical data supports the inhibition of tumour cancer cell growth associated with mTOR inhibition and a decrease in phosphorylation of S6K, rpS6 and 4E-BP1. Here we have summarised some of the preclinical data and data of many clinical trials that are exploring the true value of metformin for cancer patients, mainly breast and prostate cancer. PMID:21680296

  11. [Metformin impact on purine metabolism in breast cancer].

    PubMed

    Shatova, O P; Butenko, Eu V; Khomutov, Eu V; Kaplun, D S; Sedakov, I Eu; Zinkovych, I I

    2016-03-01

    Large-scale epidemiological and clinical studies have demonstrated the efficacy of metformin in oncology practice. However, the mechanisms of implementation of the anti-tumor effect of this drug there is still need understanding. In this study we have investigated the effect of metformin on the activity of adenosine deaminase and respectively adenosinergic immunosuppression in tumors and their microenvironment. The material of the study was taken during surgery of breast cacer patients receiveing metformin, and also patients which did not take this drug. The adenosine deaminase activity and substrate (adenosine) and products (inosine, hypoxanthine) concentrations were determined by HPLC. Results of this study suggest that metformin significantly alters catabolism of purine nucleotides in the node breast adenocarcinoma tisue. However, the metformin-induced increase in the adenosine deaminase activity is not sufficient to reduce the level of adenosine in cancer tissue. Thus, in metformin treated patients the adenosine concentration remained unchanged, and inosine and hypoxanthine concentration significantly increased. PMID:27420623

  12. Lack of cardioprotection by single-dose magnesium prophylaxis on isoprenaline-induced myocardial infarction in adult Wistar rats

    PubMed Central

    Garson, Christie; Kelly-Laubscher, Roisin; Gwanyanya, Asfree; Blackhurst, Dee

    2015-01-01

    Summary Aim Magnesium (Mg2+) is effective in treating cardiovascular disorders such as arrhythmias and pre-eclampsia, but its role during myocardial infarction (MI) remains uncertain. In this study, we investigated the effects of Mg2+ pre-treatment on isoprenaline (ISO)-induced MI in vivo. Methods Rats divided into four groups were each pre-treated with either MgSO4 (270 mg/kg intraperitoneally) or an equivalent volume of physiological saline, prior to the ISO (67 mg/kg subcutaneously) or saline treatments. One day post-treatment, the electrocardiogram and left ventricular blood pressures were recorded. Infarcts were determined using 2,3,5-triphenyltetrazolium chloride staining, and serum markers of lipid peroxidation were measured with spectrophotometric assays. Results Mg2+ pre-treatment neither altered the ISO-induced infarct size compared with ISO treatment alone (p > 0.05), nor reversed the low-voltage electrocardiogram or the prominent Q waves induced by ISO, despite a trend to decreased Q waves. Similarly, Mg2+ did not prevent the ISO-induced decrease in peak left ventricular blood pressure or the decrease in minimal rate of pressure change. Mg2+ did not reverse the ISO-induced gain in heart weight or loss of body weight. Neither ISO nor Mg2+ altered the concentrations of lipid peroxidation markers 24 hours post MI induction. Conclusion Although Mg2+ had no detrimental effects on electrical or haemodynamic activity in ISO-induced MI, the lack of infarct prevention may detract from its utility in MI therapy. PMID:26212925

  13. The pleiotropic effects of metformin: time for prospective studies.

    PubMed

    Bromage, Daniel I; Yellon, Derek M

    2015-01-01

    The global prevalence of diabetes has risen to epidemic proportions and the trend is predicted to continue. The consequent burden of cardiovascular morbidity and mortality is a major public health concern and new treatments are required to mitigate the deleterious effects of cardiovascular disease in diabetic patients. Ischaemia-reperfusion injury is well known to exacerbate the harmful effects of acute myocardial infarction and subsequent therapeutic reperfusion, and several mechanical and pharmacological approaches to mitigating this injury have been investigated. Metformin, which is cheap, relatively safe and widely used in type 2 diabetes, is one such pharmacotherapy with considerable pre-clinical evidence for cardioprotective utility beyond its glucose-lowering effect. However, despite convincing basic evidence its translation to clinical application has largely been limited to studies of cardiovascular risk. There are several barriers to prospective randomized assessment in the context of acute myocardial infarction, not least the accessibility and already widespread use of metformin among patients with type 2 diabetes at high risk of cardiovascular events. In the place of class 1 evidence, well-designed prospective cohort studies of the potential pleiotropic utility of metformin in cardiovascular disease, and particularly its benefit in ischaemia-reperfusion injury, are needed. Given the availability of metformin worldwide, this is particularly true in low- and middle-income countries where the optimal therapy for acute myocardial infarction, primary percutaneous coronary intervention, may not be available, and instead patients are managed with thrombolysis. As this is less effective, metformin as an adjunct to thrombolysis (or PPCI) could represent an effective, cheap means of cardioprotection with global relevance. PMID:26271457

  14. Redox signalling and cardioprotection: translatability and mechanism

    PubMed Central

    Pagliaro, P; Penna, C

    2015-01-01

    The morbidity and mortality from coronary artery disease (CAD) remain significant worldwide. The treatment for acute myocardial infarction has improved over the past decades, including early reperfusion of culprit coronary arteries. Although it is mandatory to reperfuse the ischaemic territory as soon as possible, paradoxically this leads to additional myocardial injury, namely ischaemia/reperfusion (I/R) injury, in which redox stress plays a pivotal role and for which no effective therapy is currently available. In this review, we report evidence that the redox environment plays a pivotal role not only in I/R injury but also in cardioprotection. In fact, cardioprotective strategies, such as pre- and post-conditioning, result in a robust reduction in infarct size in animals and the role of redox signalling is of paramount importance in these conditioning strategies. Nitrosative signalling and cysteine redox modifications, such as S-nitrosation/S-nitrosylation, are also emerging as very important mechanisms in conditioning cardioprotection. The reasons for the switch from protective oxidative/nitrosative signalling to deleterious oxidative/nitrosative/nitrative stress are not fully understood. The complex regulation of this switch is, at least in part, responsible for the diminished or lack of cardioprotection induced by conditioning protocols observed in ageing animals and with co-morbidities as well as in humans. Therefore, it is important to understand at a mechanistic level the reasons for these differences before proposing a safe and useful transition of ischaemic or pharmacological conditioning. Indeed, more mechanistic novel therapeutic strategies are required to protect the heart from I/R injury and to improve clinical outcomes in patients with CAD. PMID:25303224

  15. Cardioprotective Activity of Methanol Extract of fruit of Trichosanthes cucumerina on Doxorubicin-induced Cardiotoxicity in Wistar Rats

    PubMed Central

    Shah, Sagar L.; Mali, Vishal R.; Zambare, Girish N.; Bodhankar, Subhash L.

    2012-01-01

    Aim and Objective: The objective was to determine the activity of methanol extract of fruit of Trichosanthes cucumerina in doxorubicin-induced cardiotoxicity in rats. Materials and Methods: The methanol extract of fruit of T. cucumerina was prepared. Male Wistar rats were divided in four groups. Group I was vehicle control. Group II animals received doxorubicin 4 mg/kg i.p. on days 21, 28, 35, and 42. Group III and IV animals were treated with methanol extract of T. cucumerina (500 and 1000 mg/kg, respectively) for 49 days. Doxorubicin was administered on days 21, 28, 35, and 42 days. The parameters of study were body weight, serum biomarkers, ECG, blood pressure, and left ventricular function. At the end of the study, the histology of heart, liver, and kidney was carried out. Results: Cardiac toxicity by doxorubicin was manifested as body weight loss, elevated serum LDH and CK-MB, increased ST, QT and QRS complex, reduced blood pressure, and left ventricular function. The methanol extract of T. cucumerina significantly decreased LDH and CK-MB, reduced ST, QT interval and QRS complex, increased heart rate, restored blood pressure, and left ventricular function. Doxorubicin caused liver and kidney necrosis, cellular infiltration, and vascular changes that indicated injury. Conclusion: T. cucumerina (1000 mg/kg) reduced the severity of doxorubicin-induced cardiac damage especially in heart. It is concluded that doxorubicin-induced cardiotoxicity is reduced by pretreatment with methanol extract of fruit of T. cucumerina. PMID:22778516

  16. Terminalia arjuna (Roxb.) Wight & Arn. augments cardioprotection via antioxidant and antiapoptotic cascade in isoproterenol induced cardiotoxicity in rats.

    PubMed

    Shukla, Santosh K; Sharma, Suman B; Singh, Usha R; Ahmad, Sayeed; Dwivedi, Shridhar

    2015-12-01

    Worldwide, Ischemic heart disease (IHD) affects a large population. Implication of myocardial infarction (MI) and its multiple pathophysiology in cardiac function is well known. Further, isoproterenol (ISP) is known to induce MI. Today, there is an urgent need for effective drug that could limit the myocardial injury. Therapeutic intervention with antioxidants has been shown useful in preventing the deleterious changes produced by ISP. Here, we investigated the protective effects of oral pre-treatment of hydroalcoholic extract of bark of Terminalia arjuna (HETA) on biochemical and apoptotic changes during cardiotoxicity induced by isoproterenol (ISP) in rats. HETA was orally administered at a dose of 100, 200 and 400 mg/kg body wt., for 30 days with concurrent administration of ISP (85 mg/kg body wt.) on days 28th and 29th at an interval of 24 h. ISP caused deleterious changes in the myocardium and significantly increased (P < 0.05) malondialdehyde, serum glutamate oxaloacitate transaminase, creatine kinase-MB, lactate dehydrogenase and troponin-I. However, it significantly decreased (P < 0.05) glutathione and superoxide dismutase compared to healthy control. Oral pre-treatment of HETA for 30 days significantly decreased (P < 0.05) the biochemical parameters of oxidative stress and cardiac markers as compared to ISP control. Histopathological findings also revealed that architecture of the myocardium was restored towards normal in HETA pre-treated group. Overall, the present study has shown that the hydroalcoholic extract of bark of T. arjuna (HETA) attenuates oxidative stress, apoptosis and improves antioxidant status in ISP-induced cardiotoxicity in rats. PMID:26742326

  17. Transmucosal delivery of metformin- a comprehensive study.

    PubMed

    Sushma, M; Raju, Y Prasanna; Sundaresan, C R; Vandana, K R; Kumar, N Vijay; Chowdary, V Harini

    2014-01-01

    Discovered in the 1920s, the biguanide metformin hydrochloride is still the first line drug in the management of Type 2 diabetes mellitus. Metformin hydrochloride is absorbed slowly and incompletely from the gastrointestinal tract. The present research work was undertaken with the aim of developing a fast dissolving film of metformin hydrochloride, suitable for oral trans mucosal administration. Fast dissolving films allow rapid drug dissolution in the oral cavity, ensuring bypass of first pass metabolism resulting in rapid absorption. Films of metformin were prepared by solvent casting method using Hydroxypropyl methylcellulose K15 (HPMC). Six formulations (F1-F6) of metformin hydrochloride were prepared and evaluated for their physical characteristics such as tackiness, thickness, tensile strength, elongation, weight variation, folding endurance, drug content and surface pH. The compatibility of the drug with HPMC was confirmed by FTIR studies. The formulations were subjected to disintegration, in-vitro drug release and the optimised formulation was evaluated for pharmacodynamic studies in diabetic rats. Among the formulations (F1-F6) F4 was found to be the best formulation which contained Hydroxypropyl methyl cellulose K15 at weight ratios of 1:4 and showed excellent film forming characteristics such as disintegration time at 42 sec and percentage drug release of 94.2% within 5 minutes. Pharmacodynamic assessment in diabetes induced rats demonstrated that the fast dissolving films of metformin had a quicker onset of action compared to conventional formulation. PMID:23848354

  18. A New Therapeutic Modality for Acute Myocardial Infarction: Nanoparticle-Mediated Delivery of Pitavastatin Induces Cardioprotection from Ischemia-Reperfusion Injury via Activation of PI3K/Akt Pathway and Anti-Inflammation in a Rat Model

    PubMed Central

    Nagaoka, Kazuhiro; Matoba, Tetsuya; Mao, Yajing; Nakano, Yasuhiro; Ikeda, Gentaro; Egusa, Shizuka; Tokutome, Masaki; Nagahama, Ryoji; Nakano, Kaku; Sunagawa, Kenji; Egashira, Kensuke

    2015-01-01

    Aim There is an unmet need to develop an innovative cardioprotective modality for acute myocardial infarction (AMI), for which the effectiveness of interventional reperfusion therapy is hampered by myocardial ischemia-reperfusion (IR) injury. Pretreatment with statins before ischemia is shown to reduce MI size in animals. However, no benefit was found in animals and patients with AMI when administered at the time of reperfusion, suggesting insufficient drug targeting into the IR myocardium. Here we tested the hypothesis that nanoparticle-mediated targeting of pitavastatin protects the heart from IR injury. Methods and Results In a rat IR model, poly(lactic acid/glycolic acid) (PLGA) nanoparticle incorporating FITC accumulated in the IR myocardium through enhanced vascular permeability, and in CD11b-positive leukocytes in the IR myocardium and peripheral blood after intravenous treatment. Intravenous treatment with PLGA nanoparticle containing pitavastatin (Pitavastatin-NP, 1 mg/kg) at reperfusion reduced MI size after 24 hours and ameliorated left ventricular dysfunction 4-week after reperfusion; by contrast, pitavastatin alone (as high as 10 mg/kg) showed no therapeutic effects. The therapeutic effects of Pitavastatin-NP were blunted by a PI3K inhibitor wortmannin, but not by a mitochondrial permeability transition pore inhibitor cyclosporine A. Pitavastatin-NP induced phosphorylation of Akt and GSK3β, and inhibited inflammation and cardiomyocyte apoptosis in the IR myocardium. Conclusions Nanoparticle-mediated targeting of pitavastatin induced cardioprotection from IR injury by activation of PI3K/Akt pathway and inhibition of inflammation and cardiomyocyte death in this model. This strategy can be developed as an innovative cardioprotective modality that may advance currently unsatisfactory reperfusion therapy for AMI. PMID:26167913

  19. Vagal modulation of high mobility group box-1 protein mediates electroacupuncture-induced cardioprotection in ischemia-reperfusion injury

    PubMed Central

    Zhang, Juan; Yong, Yue; Li, Xing; Hu, Yu; Wang, Jian; Wang, Yong-qiang; Song, Wei; Chen, Wen-ting; Xie, Jian; Chen, Xue-mei; Lv, Xin; Hou, Li-li; Wang, Ke; Zhou, Jia; Wang, Xiang-rui; Song, Jian-gang

    2015-01-01

    Excessive release of high mobility group box-1 (HMGB1) protein from ischemic cardiomyocytes activates inflammatory cascades and enhances myocardial injury after reperfusion. Here we report evidence that electroacupuncture of mice at Neiguan acupoints can inhibit the up-regulation of cardiac HMGB1 following myocardial ischemia and attenuate the associated inflammatory responses and myocardial injury during reperfusion. These benefits of electroacupuncture were partially reversed by administering recombinant HMGB1 to the mice, and further potentiated by administering anti-HMGB1 antibody. Electroacupuncture-induced inhibition of HMGB1 release was markedly reduced by unilateral vagotomy or administration of nicotinic receptor antagonist, but not by chemical sympathectomy. The cholinesterase inhibitor neostigmine mimicked the effects of electroacupuncture on HMGB1 release and myocardial ischemia reperfusion injury. Culture experiments with isolated neonatal cardiomyocytes showed that acetylcholine, but not noradrenaline, inhibited hypoxia-induced release of HMGB1 via a α7nAchR-dependent pathway. These results suggest that electroacupuncture acts via the vagal nerve and its nicotinic receptor-mediated signaling to inhibit HMGB1 release from ischemic cardiomyocytes. This helps attenuate pro-inflammatory responses and myocardial injury during reperfusion. PMID:26499847

  20. Cardioprotective activity of alcoholic extract of Tinospora cordifolia (Willd.) Miers in calcium chloride-induced cardiac arrhythmia in rats

    PubMed Central

    Sharma, Ashish Kumar; Kishore, Kunal; Sharma, Divya; Srinivasan, B.P; Agarwal, Shyam Sunder; Sharma, Ashok; Singh, Santosh Kumar; Gaur, Samir; Jatav, Vijay Singh

    2011-01-01

    The present study investigated the antiarrhythmic activity of alcoholic extract of Tinospora cordifolia (T. cordifolia) in CaCl2 induced arrhythmia. CaCl2 (25 mg/kg) was administered by intravenous infusion (iv) to produce arrhythmia in rats. The animals were then treated with T. cordifolia extract (150, 250, and 450 mg/kg) and verapamil (5 mg/kg,iv). Lead II electrocardiogram was monitored. Plasma calcium, sodium and potassium levels were measured. In CaCl2 induced arrhythmia, heart rate was decreased by 41.10%, T. cordifolia at 150, 300, and 450 mg/kg decreased the heart rate by 26.30%, 29.16%, and 38.29%, respectively, and verapamil reduced the heart rate by 9.70% compared to the normal group. The PQRST waves were normalized and atrial and ventricular fibrillation was controlled in rats treated with verapamil and T. cordifolia. CaCl2 increased calcium and sodium levels and decreased potassium levels in blood. T. cordifolia dose-dependently decreased calcium and sodium levels and increased potassium levels. Hence, T. cordifolia can be used in antiarrhythmic clinical settings and beneficial in atrial and ventricular fibrillation and flutter and may be indicated in ventricular tachyarrhythmia. PMID:23554702

  1. Cardioprotective potential of N,α-L-rhamnopyranosyl vincosamide, an indole alkaloid, isolated from the leaves of Moringa oleifera in isoproterenol induced cardiotoxic rats: in vivo and in vitro studies.

    PubMed

    Panda, Sunanda; Kar, Anand; Sharma, Pratibha; Sharma, Ashok

    2013-02-15

    Hitherto unknown protective effect of N,α-L-rhamnopyranosyl vincosamide (VR), isolated from Moringa oleifera leaves in isoproterenol (ISO)-induced cardiac toxicity was evaluated in rats. Oral administration of VR at 40 mg/kg for 7 days markedly reduced the ISO-induced increase in the levels of serum cardiac markers such as troponin-T, creatine kinase-MB, lactate dehydrogenase and glutamate pyruvate transaminase as well as cardiac lipid peroxidation with a parallel increase in the cellular antioxidants suggesting its cardio-protective and free radical scavenging potential, which was latter confirmed by in vitro study. Rats treated with test compound also improved the ISO-induced abnormal changes in ECG as well as in cardiac histology. A reduction in myocardial necrosis was further evidenced by the tri-phenyl tetrazolium chloride (TTC) stain in isolated test drug pretreated rats. These findings suggest the cardio-protective potential of the isolated alkaloid and possibly the beneficial action is mediated through its free radical scavenging property. PMID:23321560

  2. Cardioprotective effect of methanolic extract of Marrubium vulgare L. on isoproterenol-induced acute myocardial infarction in rats.

    PubMed

    Yousefi, Keyvan; Soraya, Hamid; Fathiazad, Fatemeh; Khorrami, Arash; Hamedeyazdan, Sanaz; Maleki-Dizaji, Nasrin; Garjani, Alireza

    2013-08-01

    Isoproterenol injection (100 mg/kg; sc) produced changes in ECG pattern including ST-segment elevation and suppressed R-amplitude. The methanolic extract of M. vulgare at doses of 10, 20, and 40 mg/kg significantly amended the ECG changes. A severe myocardial necrosis and edematous along with a sharp reduction in the arterial blood pressure, left ventricular contractility (LVdP/dt(max or min)), but a marked increase in the left ventricular end-diastolic pressure (LVEDP) were seen in the isoproterenol group. All parameters were significantly improved by the extract treatment. The extract (10 mg/kg) strongly increased LVdP/dt(max). Similarly, treatment with 40 mg/kg of M. vulgare lowered the elevated LVEDP and the heart to body weight ratio. In addition to in vitro antioxidant activity, the extract suppressed markedly the elevation of malondialdehyde levels both in serum and in myocardium. The results demonstrate that M. vulgare protects myocardium against isoproterenol-induced acute myocardial infarction and suggest that the effects could be related to antioxidant activities. PMID:24228389

  3. Hexokinases and Cardioprotection

    PubMed Central

    Calmettes, Guillaume; Ribalet, Bernard; John, Scott; Korge, Paavo; Ping, Peipei; Weiss, James N.

    2014-01-01

    As mediators of the first enzymatic step in glucose metabolism, hexokinases (HKs) orchestrate a variety of catabolic and anabolic uses of glucose, regulate antioxidant power by generating NADPH for glutathione reduction, and modulate cell death processes by directly interacting with the voltage-dependent anion channel (VDAC), a regulatory component of the mitochondrial permeability transition pore (mPTP). Here we summarize the current state-of-knowledge about HKs and their role in protecting the heart from ischemia/reperfusion (I/R) injury, reviewing: 1) the properties of different HK isoforms and how their function is regulated by their subcellular localization; 2) how HKs modulate glucose metabolism and energy production during I/R; 3) the molecular mechanisms by which HKs influence mPTP opening and cellular injury during I/R; 4) how different metabolic and HK profiles correlate with susceptibility to I/R injury and cardioprotective efficacy in cancer cells, neonatal hearts, and normal, hypertrophied and failing adult hearts, and how these difference may guide novel therapeutic strategies to limit I/R injury in the heart. PMID:25264175

  4. Revisiting Metformin: Annual Vitamin B12 Supplementation may become Mandatory with Long-Term Metformin Use.

    PubMed

    Mahajan, R; Gupta, K

    2010-10-01

    Monitoring of adverse drug reactions of a drug is a continuous process and runs through-out the life of a drug. Many rare adverse effects of a drug are documented after years of use; when a single case (signal generation) is reported leading subsequently to reporting of more cases. Deficiency of Vitamin B12 (vit B(12)) is a known sequel of prolonged metformin therapy. It was recommended to have annual measurement of serum vit B(12) levels in patients on long term metformin therapy way back in 1970 itself. After more than 50 years of use of metformin, we have come to know that metformin induced vit B(12) deficiency can cause neuropathy; forcing to change the recommendation from annual screening of vit B(12) levels to annual supplementation of vit B(12). PMID:21264109

  5. Distinct cardioprotective mechanisms of immediate, early and delayed ischaemic postconditioning.

    PubMed

    Barsukevich, Veronika; Basalay, Marina; Sanchez, Jenifer; Mrochek, Alexander; Whittle, John; Ackland, Gareth L; Gourine, Alexander V; Gourine, Andrey

    2015-01-01

    Cardioprotection against ischaemia/reperfusion injury in mice can be achieved by delayed ischaemic postconditioning (IPost) applied as late as 30 min after the onset of reperfusion. We determined the efficacy of delayed IPost in a rat model of myocardial infarction (MI) and investigated potential underlying mechanisms of this phenomenon. Rats were subjected to 20, 30 or 45 min of coronary artery occlusion followed by 120 min of reperfusion (I/R). Immediate and early IPost included six cycles of I/R (10/10 s) applied 10 s or 10 min after reperfusion onset. In the second series of experiments, the rats were subjected to 30 min of coronary occlusion followed by IPost applied 10 s, 10, 30, 45 or 60 min after the onset of reperfusion. Immediate and early IPost (applied 10 s or 10 min of reperfusion) established cardioprotection only when applied after a period of myocardial ischaemia lasting 30 min. Delayed IPost applied after 30 or 45 min of reperfusion reduced infarct sizes by 36 and 41 %, respectively (both P < 0.01). IPost applied 60 min after reperfusion onset was ineffective. Inhibition of RISK pathway (administration of ERK1/2 inhibitor PD-98059 or PI3K inhibitor LY-294002) abolished cardioprotection established by immediate IPost but had no effect on cardioprotection conferred by early IPost. Blockade of SAFE pathway using JAK/STAT inhibitor AG490 had no effect on the immediate or early IPost cardioprotection. Blockade of mitochondrial KATP (mitoKATP) channels (with 5-Hydroxydecanoate) abolished cardioprotection achieved by immediate and early IPost, but had no effect on cardioprotection when IPost was applied 30 or 45 min into the reperfusion period. Immediate IPost increased phosphorylation of PI3K-AKT and ERK1/2. Early or delayed IPost had no effect on phosphorylation of PI3K-AKT, ERK1/2 or STAT3. These data show that in the rat model, delayed IPost confers significant cardioprotection even if applied 45 min after onset of reperfusion. Cardioprotection

  6. Thyroid Hormone and Cardioprotection.

    PubMed

    Gerdes, Anthony Martin; Ojamaa, Kaie

    2016-01-01

    The heart is a major target of thyroid hormones, with maintenance of euthyroid hormone balance critical for proper function. In particular, chronic low thyroid function can eventually lead to dilated heart failure with impaired coronary blood flow. New evidence also suggests that heart diseases trigger a reduction in cardiac tissue thyroid hormone levels, a condition that may not be detectible using serum hormone assays. Many animal and clinical studies have demonstrated a high prevalence of low thyroid function in heart diseases with worse outcomes from this condition. Animal and human studies have also demonstrated many benefits from thyroid hormone treatment of heart diseases, particularly heart failure. Nonetheless, this potential treatment has not yet translated to patients due to a number of important concerns. The most serious concern involves the potential of accidental overdose leading to increased arrhythmias and sudden death. Several important clinical studies, which actually used excessive doses of thyroid hormone analogs, have played a major role in convincing the medical community that thyroid hormones are simply too dangerous to be considered for treatment in cardiac patients. Nonetheless, this issue has not gone away due primarily to overwhelmingly positive evidence for treatment benefits and a new understanding of the cellular and molecular mechanisms underlying those benefits. This review will first discuss the clinical evidence for the use of thyroid hormones as a cardioprotective agent and then provide an overview of the cellular and molecular mechanisms underlying beneficial changes from thyroid hormone treatment of heart diseases. © 2016 American Physiological Society. Compr Physiol 6:1199-1219, 2016. PMID:27347890

  7. Pharmacometabolomic Assessment of Metformin in Non-diabetic, African Americans

    PubMed Central

    Rotroff, Daniel M.; Oki, Noffisat O.; Liang, Xiaomin; Yee, Sook Wah; Stocker, Sophie L.; Corum, Daniel G.; Meisner, Michele; Fiehn, Oliver; Motsinger-Reif, Alison A.; Giacomini, Kathleen M.; Kaddurah-Daouk, Rima

    2016-01-01

    Millions of individuals are diagnosed with type 2 diabetes mellitus (T2D), which increases the risk for a plethora of adverse outcomes including cardiovascular events and kidney disease. Metformin is the most widely prescribed medication for the treatment of T2D; however, its mechanism is not fully understood and individuals vary in their response to this therapy. Here, we use a non-targeted, pharmacometabolomics approach to measure 384 metabolites in 33 non-diabetic, African American subjects dosed with metformin. Three plasma samples were obtained from each subject, one before and two after metformin administration. Validation studies were performed in wildtype mice given metformin. Fifty-four metabolites (including 21 unknowns) were significantly altered upon metformin administration, and 12 metabolites (including six unknowns) were significantly associated with metformin-induced change in glucose (q < 0.2). Of note, indole-3-acetate, a metabolite produced by gut microbes, and 4-hydroxyproline were modulated following metformin exposure in both humans and mice. 2-Hydroxybutanoic acid, a metabolite previously associated with insulin resistance and an early biomarker of T2D, was positively correlated with fasting glucose levels as well as glucose levels following oral glucose tolerance tests after metformin administration. Pathway analysis revealed that metformin administration was associated with changes in a number of metabolites in the urea cycle and in purine metabolic pathways (q < 0.01). Further research is needed to validate the biomarkers of metformin exposure and response identified in this study, and to understand the role of metformin in ammonia detoxification, protein degradation and purine metabolic pathways. PMID:27378919

  8. Glucose promotes breast cancer aggression and reduces metformin efficacy

    PubMed Central

    Wahdan-Alaswad, Reema; Fan, Zeying; Edgerton, Susan M; Liu, Bolin; Deng, Xin-Sheng; Arnadottir, Sigrid Salling; Richer, Jennifer K; Anderson, Steven M; Thor, Ann D

    2013-01-01

    Metformin treatment has been associated with a decrease in breast cancer risk and improved survival. Metformin induces complex cellular changes, resulting in decreased tumor cell proliferation, reduction of stem cells, and apoptosis. Using a carcinogen-induced rodent model of mammary tumorigenesis, we recently demonstrated that overfeeding in obese animals is associated with a 50% increase in tumor glucose uptake, increased proliferation, and tumor cell reprogramming to an “aggressive” metabolic state. Metformin significantly inhibited these pro-tumorigenic effects. We hypothesized that a dynamic relationship exists between chronic energy excess (glucose by dose) and metformin efficacy/action. Media glucose concentrations above 5 mmol/L was associated with significant increase in breast cancer cell proliferation, clonogenicity, motility, upregulation/activation of pro-oncogenic signaling, and reduction in apoptosis. These effects were most significant in triple-negative breast cancer (TNBC) cell lines. High-glucose conditions (10 mmol/L or above) significantly abrogated the effects of metformin. Mechanisms of metformin action at normal vs. high glucose overlapped but were not identical; for example, metformin reduced IGF-1R expression in both the HER2+ SK-BR-3 and TNBC MDA-MB-468 cell lines more significantly at 5, as compared with 10 mmol/L glucose. Significant changes in gene profiles related to apoptosis, cellular processes, metabolic processes, and cell proliferation occurred with metformin treatment in cells grown at 5 mmol/L glucose, whereas under high-glucose conditions, metformin did not significantly increase apoptotic/cellular death genes. These data indicate that failure to maintain glucose homeostasis may promote a more aggressive breast cancer phenotype and alter metformin efficacy and mechanisms of action. PMID:24107633

  9. Metformin - For the dermatologist.

    PubMed

    Bubna, Aditya Kumar

    2016-01-01

    Metformin though primarily an antidiabetic drug, has found to play an important role in a number of cutaneous disorders. Because of its role in improving hyperinsulinemia, it has proven beneficial in hormonal acne, hidradenitis suppurativa (HS) and acanthosis nigricans. Its antiandrogenic properties further serve as an add-on to the conventional management of hirsutism associated with polycystic ovarian syndrome. Very recently, systemic usage of metformin for psoriasis and cutaneous malignancies has shown promising results. Interestingly, metformin has also been topically used in hyperpigmentary disorders with pertinent levels of improvement and happens to be the most recent addition to the list of dermatologic indications. Though an oral hypoglycemic agent to begin with, metformin today has proven to be a boon for dermatologists. PMID:26997714

  10. Metformin - For the dermatologist

    PubMed Central

    Bubna, Aditya Kumar

    2016-01-01

    Metformin though primarily an antidiabetic drug, has found to play an important role in a number of cutaneous disorders. Because of its role in improving hyperinsulinemia, it has proven beneficial in hormonal acne, hidradenitis suppurativa (HS) and acanthosis nigricans. Its antiandrogenic properties further serve as an add-on to the conventional management of hirsutism associated with polycystic ovarian syndrome. Very recently, systemic usage of metformin for psoriasis and cutaneous malignancies has shown promising results. Interestingly, metformin has also been topically used in hyperpigmentary disorders with pertinent levels of improvement and happens to be the most recent addition to the list of dermatologic indications. Though an oral hypoglycemic agent to begin with, metformin today has proven to be a boon for dermatologists. PMID:26997714

  11. Metformin and Pregnancy

    MedlinePlus

    ... diabetes and insulin resistance in polycystic ovarian syndrome (PCOS). Other names for this medication include Glucophage®, Diformin®, ... care provider. I am taking metformin to treat PCOS. Should I stop taking the medication before and/ ...

  12. Metformin Induces Cell Cycle Arrest, Reduced Proliferation, Wound Healing Impairment In Vivo and Is Associated to Clinical Outcomes in Diabetic Foot Ulcer Patients

    PubMed Central

    Ochoa-Gonzalez, Fatima; Cervantes-Villagrana, Alberto R.; Fernandez-Ruiz, Julio C.; Nava-Ramirez, Hilda S.; Hernandez-Correa, Adriana C.; Enciso-Moreno, Jose A.; Castañeda-Delgado, Julio E.

    2016-01-01

    Background Several epidemiological studies in diabetic patients have demonstrated a protective effect of metformin to the development of several types of cancer. The underlying mechanisms of such phenomenon is related to the effect of metformin on cell proliferation among which, mTOR, AMPK and other targets have been identified. However, little is known about the role that metformin treatment have on other cell types such as keratinocytes and whether exposure to metformin of these cells might have serious repercussions in wound healing delay and in the development of complications in diabetic patients with foot ulcers or in their exacerbation. Material and Methods HaCaT Cells were exposed to various concentrations of metformin and cell viability was evaluated by a Resazurin assay; Proliferation was also evaluated with a colony formation assay and with CFSE dilution assay by flow cytometry. Cell cycle was also evaluated by flow cytometry by PI staining. An animal model of wound healing was used to evaluate the effect of metformin in wound closure. Also, an analysis of patients receiving metformin treatment was performed to determine the effect of metformin treatment on the outcome and wound area. Statistical analysis was performed on SPSS v. 18 and GraphPad software v.5. Results Metformin treatment significantly reduces cell proliferation; colony formation and alterations of the cell cycle are observed also in the metformin treated cells, particularly in the S phase. There is a significant increase in the area of the wound of the metformin treated animals at different time points (P<0.05). There is also a significant increase in the size and wound area of the patients with diabetic foot ulcers at the time of hospitalization. A protective effect of metformin was observed for amputation, probably associated with the anti inflammatory effects reported of metformin. Conclusions Metformin treatment reduces cell proliferation and reduces wound healing in an animal model

  13. Cardioprotective Effects of Total Flavonoids Extracted from Xinjiang Sprig Rosa rugosa against Acute Ischemia/Reperfusion-Induced Myocardial Injury in Isolated Rat Heart.

    PubMed

    Hou, Xuejiao; Han, Jichun; Yuan, Changsheng; Ren, Huanhuan; Zhang, Ya; Zhang, Tao; Xu, Lixia; Zheng, Qiusheng; Chen, Wen

    2016-01-01

    This study evaluated the antioxidative and cardioprotective effects of total flavonoids extracted from Xinjiang sprig Rosa rugosa on ischemia/reperfusion (I/R) injury using an isolated Langendorff rat heart model. The possible mechanism of Xinjiang sprig rose total flavonoid (XSRTF) against I/R injury was also studied. XSRTF (5, 10, and 20 µg/mL) dissolved in Krebs-Henseleit buffer was administered to isolated rat heart. The XSRTF showed remarkable scavenging effects against 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, and superoxide anion radicals in vitro. XSRTF pretreatment improved the heart rate, increased LVDP, and decreased CK and LDH levels in coronary flow. This pretreatment also increased SOD activity and GSH/GSSG ratio but decreased MDA, TNF-α, and CRP levels and IL-8 and IL-6 activities. The infarct size and cell apoptosis in the hearts from the XSRTF-treated group were lower than those in the hearts from the I/R group. Therefore, the cardioprotective effects of XSRTF may be attributed to its antioxidant, antiapoptotic, and anti-inflammatory activities. PMID:25617974

  14. Clinical pharmacokinetics of metformin.

    PubMed

    Graham, Garry G; Punt, Jeroen; Arora, Manit; Day, Richard O; Doogue, Matthew P; Duong, Janna K; Furlong, Timothy J; Greenfield, Jerry R; Greenup, Louise C; Kirkpatrick, Carl M; Ray, John E; Timmins, Peter; Williams, Kenneth M

    2011-02-01

    Metformin is widely used for the treatment of type 2 diabetes mellitus. It is a biguanide developed from galegine, a guanidine derivative found in Galega officinalis (French lilac). Chemically, it is a hydrophilic base which exists at physiological pH as the cationic species (>99.9%). Consequently, its passive diffusion through cell membranes should be very limited. The mean ± SD fractional oral bioavailability (F) of metformin is 55 ± 16%. It is absorbed predominately from the small intestine. Metformin is excreted unchanged in urine. The elimination half-life (t(½)) of metformin during multiple dosages in patients with good renal function is approximately 5 hours. From published data on the pharmacokinetics of metformin, the population mean of its clearances were calculated. The population mean renal clearance (CL(R)) and apparent total clearance after oral administration (CL/F) of metformin were estimated to be 510 ± 130 mL/min and 1140 ± 330 mL/min, respectively, in healthy subjects and diabetic patients with good renal function. Over a range of renal function, the population mean values of CL(R) and CL/F of metformin are 4.3 ± 1.5 and 10.7 ± 3.5 times as great, respectively, as the clearance of creatinine (CL(CR)). As the CL(R) and CL/F decrease approximately in proportion to CL(CR), the dosage of metformin should be reduced in patients with renal impairment in proportion to the reduced CL(CR). The oral absorption, hepatic uptake and renal excretion of metformin are mediated very largely by organic cation transporters (OCTs). An intron variant of OCT1 (single nucleotide polymorphism [SNP] rs622342) has been associated with a decreased effect on blood glucose in heterozygotes and a lack of effect of metformin on plasma glucose in homozygotes. An intron variant of multidrug and toxin extrusion transporter [MATE1] (G>A, SNP rs2289669) has also been associated with a small increase in antihyperglycaemic effect of metformin. Overall, the effect of structural

  15. Metformin inhibits pancreatic cancer cell and tumor growth and downregulates Sp transcription factors.

    PubMed

    Nair, Vijayalekshmi; Pathi, Satya; Jutooru, Indira; Sreevalsan, Sandeep; Basha, Riyaz; Abdelrahim, Maen; Samudio, Ismael; Safe, Stephen

    2013-12-01

    Metformin is a widely used antidiabetic drug, and epidemiology studies for pancreatic and other cancers indicate that metformin exhibits both chemopreventive and chemotherapeutic activities. Several metformin-induced responses and genes are similar to those observed after knockdown of specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 by RNA interference, and we hypothesized that the mechanism of action of metformin in pancreatic cancer cells was due, in part, to downregulation of Sp transcription factors. Treatment of Panc1, L3.6pL and Panc28 pancreatic cancer cells with metformin downregulated Sp1, Sp3 and Sp4 proteins and several pro-oncogenic Sp-regulated genes including bcl-2, survivin, cyclin D1, vascular endothelial growth factor and its receptor, and fatty acid synthase. Metformin induced proteasome-dependent degradation of Sps in L3.6pL and Panc28 cells, whereas in Panc1 cells metformin decreased microRNA-27a and induced the Sp repressor, ZBTB10, and disruption of miR-27a:ZBTB10 by metformin was phosphatase dependent. Metformin also inhibited pancreatic tumor growth and downregulated Sp1, Sp3 and Sp4 in tumors in an orthotopic model where L3.6pL cells were injected directly into the pancreas. The results demonstrate for the first time that the anticancer activities of metformin are also due, in part, to downregulation of Sp transcription factors and Sp-regulated genes. PMID:23803693

  16. Metformin inhibits pancreatic cancer cell and tumor growth and downregulates Sp transcription factors

    PubMed Central

    Safe, Stephen

    2013-01-01

    Metformin is a widely used antidiabetic drug, and epidemiology studies for pancreatic and other cancers indicate that metformin exhibits both chemopreventive and chemotherapeutic activities. Several metformin-induced responses and genes are similar to those observed after knockdown of specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 by RNA interference, and we hypothesized that the mechanism of action of metformin in pancreatic cancer cells was due, in part, to downregulation of Sp transcription factors. Treatment of Panc1, L3.6pL and Panc28 pancreatic cancer cells with metformin downregulated Sp1, Sp3 and Sp4 proteins and several pro-oncogenic Sp-regulated genes including bcl-2, survivin, cyclin D1, vascular endothelial growth factor and its receptor, and fatty acid synthase. Metformin induced proteasome-dependent degradation of Sps in L3.6pL and Panc28 cells, whereas in Panc1 cells metformin decreased microRNA-27a and induced the Sp repressor, ZBTB10, and disruption of miR-27a:ZBTB10 by metformin was phosphatase dependent. Metformin also inhibited pancreatic tumor growth and downregulated Sp1, Sp3 and Sp4 in tumors in an orthotopic model where L3.6pL cells were injected directly into the pancreas. The results demonstrate for the first time that the anticancer activities of metformin are also due, in part, to downregulation of Sp transcription factors and Sp-regulated genes. PMID:23803693

  17. Micro(mi)RNA expression profile of breast cancer epithelial cells treated with the anti-diabetic drug metformin: induction of the tumor suppressor miRNA let-7a and suppression of the TGFβ-induced oncomiR miRNA-181a.

    PubMed

    Oliveras-Ferraros, Cristina; Cufí, Sílvia; Vazquez-Martin, Alejandro; Torres-Garcia, Violeta Zenobia; Del Barco, Sonia; Martin-Castillo, Begoña; Menendez, Javier A

    2011-04-01

    An unexplored molecular scenario that might explain the inhibitory impact of the anti-diabetic drug metformin on the genesis of breast cancer relates to metformin's ability to modulate the expression status of micro (mi)RNAs. We here report the first miRNA expression profiling of human epithelial breast cancer cells cultured in the presence of metformin. We conducted real-time transcription polymerase chain reaction (qRT-PCR) Arrays to quantitatively compare the expression profile of 88 cancer-related miRNA sequences before and after treatment of MCF-7 cells, which were used as well-differentiated, epithelioid cell controls, with graded concentrations of metformin. Metformin-treated MCF-7 cells notably exhibited up to 18-fold increases in miRNA lethal-7a (let-7a) expression compared with untreated control cells. We confirmed that MCF-7 cells undergoing epithelial-to-mesenchymal (EMT) transition in response to the cytokine TGFβ notably up-regulated (~5-fold) miRNA-181a expression and exhibited better mammosphere-forming capabilities. We then explored the ability of metformin to impede TGFβ-enhanced propensity of breast cancer stem cells to form mammospheres in a miRNA-181a-related manner. Remarkably, TGFβ treatment failed to up-regulate miRNA-181a expression in the presence of metformin, which was able to fully abrogate TGFβ-enhanced mammosphere-forming ability. In addition, metformin co-treatment fully prevented TGFβ-induced down-regulation of the tumor suppressor miRNA-96 (~10-fold). Metformin's molecular functioning to prevent invasive breast cancer can be explained in terms of its previously unrecognized ability to efficiently up-regulate the tumor-suppressive miRNAs let-7a & miRNA-96 and inhibit the oncogenic miRNA-181a, thus epigenetically preserving the differentiated phenotype of mammary epithelium while preventing EMT-related cancer-initiating cell self-renewal. PMID:21368581

  18. Mechanism of sphingosine-1-phosphate induced cardioprotection against I/R injury in diabetic rat heart: Possible involvement of glycogen synthase kinase 3β and mitochondrial permeability transition pore.

    PubMed

    Rana, Ajay; Sharma, Saurabh

    2016-02-01

    There is growing evidence that diabetes mellitus causes attenuation of the bioactive metabolite of membrane sphingolipids, sphingosine-1-phosphate, and this may be a key mechanism in the decreased cardioprotective effect of ischaemic preconditioning (IPC) in the diabetic heart. Thus, this study has been designed to investigate the role and pharmacological potential of sphingosine-1-phosphate in diabetic rat heart. Diabetes was produced in Wistar rats by administration of a low dose of streptozotocin (STZ) (35 mg/kg, i.p., once) and feeding a high fat diet (HFD) for 6 weeks. Isolated rat heart was subjected to 30 min ischaemia followed by 120 min of reperfusion (I/R). The heart was subjected to pre-ischaemic treatment (before ischaemia for 20 min) and pharmacological preconditioning with the S1P agonist FTY720 (0.6 μmol/L) with and without atractyloside (an mPTP opener; in the last episode of reperfusion before I/R). Myocardial infarction was assessed in terms of increase in lactate dehydrogenase (LDH), creatinine kinase-MB (CK-MB), myeloperoxidase (MPO) level and infarct size (triphenyltetrazolium chloride staining). Immunohistochemistry analysis was done for assessment of tumour necrosis factor (TNF)-α and glycogen synthase kinase (GSK)-3β level in cardiac tissue. Pre-ischaemic treatment and pharmacological preconditioning with FTY720 significantly decreased I/R-induced myocardial infarction, TNF-alpha, GSK-3β level and release of LDH and CK-MB as compared to control group. The cardioprotective effect of S1P agonist was significantly attenuated by atractyloside. It may be concluded that S1P agonist FTY720 prevents the diabetic heart from ischaemic reperfusion injury, possibly through inhibition of GSK-3β and regulation of opening of mitochondrial permeability transition pore. PMID:26582369

  19. Tristetraprolin mediates the anti-proliferative effects of metformin in breast cancer cells.

    PubMed

    Pandiri, Indira; Chen, Yingqing; Joe, Yeonsoo; Kim, Hyo Jeong; Park, Jeongmin; Chung, Hun Taeg; Park, Jeong Woo

    2016-02-01

    Metformin, which is a drug commonly prescribed to treat type 2 diabetes, has anti-proliferative effects in cancer cells; however, the molecular mechanisms underlying this effect remain largely unknown. The aim is to investigate the role of tristetraprolin (TTP), an AU-rich element-binding protein, in anti-proliferative effects of metformin in cancer cells. p53 wild-type and p53 mutant breast cancer cells were treated with metformin, and expression of TTP and c-Myc was analyzed by semi-quantitative RT-PCR, Western blots, and promoter activity assay. Breast cancer cells were transfected with siRNA against TTP to inhibit TTP expression or c-Myc and, after metformin treatment, analyzed for cell proliferation by MTS assay. Metformin induces the expression of tristetraprolin (TTP) in breast cancer cells in a p53-independent manner. Importantly, inhibition of TTP abrogated the anti-proliferation effect of metformin. We observed that metformin decreased c-Myc levels, and ectopic expression of c-Myc blocked the effect of metformin on TTP expression and cell proliferation. Our data indicate that metformin induces TTP expression by reducing the expression of c-Myc, suggesting a new model whereby TTP acts as a mediator of metformin's anti-proliferative activity in cancer cells. PMID:26956973

  20. Cardioprotective abilities of white wine.

    PubMed

    Cui, Jianhua; Tosaki, Arpad; Cordis, Gerald A; Bertelli, Alberto A E; Bertelli, Aldo; Maulik, Nilanjana; Das, Dipak K

    2002-05-01

    To study if white wines, like red wine, can also protect the heart from ischemia reperfusion injury, ethanol-free extracts of three different white wines (WW1, WW2 and WW3) (100 mg/100 g body weight) were given orally to Sprague Dawley rats (200 g body weight) for three weeks. Control rats were given water only for the same period of time. After three weeks, rats were anesthetized and sacrificed, and the hearts excised for the preparation of isolated working rat heart. All hearts were subjected to 30 min global ischemia followed by two hours of reperfusion. The results demonstrated that among the three different white wines, only WW2 showed cardioprotection as evidenced by improved post-ischemic ventricular recovery compared to control. The amount of malonaldehyde production in white wine-fed rat hearts were lower compared to that found in control hearts indicating reduced formation of the reactive oxygen species. In vitro studies using chemiluminescence technique revealed that these white wines scavenged both superoxide anions and hydroxyl radicals. The results of our study demonstrated that only WW2 white wine provided cardioprotection as evidenced by the improved the post-ischemic contractile recovery and reduced myocardial infarct size. The cardioprotective effect of this white wine may be attributed, at least in part, from its ability to function as an in vivo antioxidant. PMID:12074987

  1. Metformin Decouples Phospholipid Metabolism in Breast Cancer Cells

    PubMed Central

    Smith, Tim A. D.; Phyu, Su M.

    2016-01-01

    Introduction The antidiabetic drug metformin, currently undergoing trials for cancer treatment, modulates lipid and glucose metabolism both crucial in phospholipid synthesis. Here the effect of treatment of breast tumour cells with metformin on phosphatidylcholine (PtdCho) metabolism which plays a key role in membrane synthesis and intracellular signalling has been examined. Methods MDA-MB-468, BT474 and SKBr3 breast cancer cell lines were treated with metformin and [3H-methyl]choline and [14C(U)]glucose incorporation and lipid accumulation determined in the presence and absence of lipase inhibitors. Activities of choline kinase (CK), CTP:phosphocholine cytidylyl transferase (CCT) and PtdCho-phospholipase C (PLC) were also measured. [3H] Radiolabelled metabolites were determined using thin layer chromatography. Results Metformin-treated cells exhibited decreased formation of [3H]phosphocholine but increased accumulation of [3H]choline by PtdCho. CK and PLC activities were decreased and CCT activity increased by metformin-treatment. [14C] incorporation into fatty acids was decreased and into glycerol was increased in breast cancer cells treated with metformin incubated with [14C(U)]glucose. Conclusion This is the first study to show that treatment of breast cancer cells with metformin induces profound changes in phospholipid metabolism. PMID:26959405

  2. [Metformin and kidney].

    PubMed

    Sessa, Concetto; Blanco, Julien; Granata, Antonio; Fatuzzo, Pasquale; Castellino, Pietro; Zanoli, Luca

    2016-01-01

    Metformin is the first choice among drugs used for the treatment of type II diabetes mellitus mainly because of several advantages: proven hypoglycemic effect, good safety profile, virtually no risk of hypoglycemia, body weight reduction, lipid-lowering effect, efficacy in preventing micro- and macrovascular complications as well as adverse cardiac and cerebrovascular events and reduced cost. Previous reports had shown an increased risk of lactic acidosis in patients receiving metformin. However, the current Guidelines have greatly limited this risk to certain categories of patients, such as those with severe chronic renal failure, particularly when predisposing risk factors such as administration of iodinated contrast are present. In this review, we reported the main data of the literature on the use of metformin in patients with chronic renal failure and both highly expected benefits and high potential risks. PMID:27374392

  3. Metformin and Cancer

    PubMed Central

    Vallianou, Natalia G.; Evangelopoulos, Angelos; Kazazis, Christos

    2013-01-01

    Metformin is well-known as an anti-diabetic drug, but it seems to possess anti-cancerous properties as well. Adenosine monophosphate-activated protein kinase (AMPK) is a highly conserved regulator of the cellular response to the presence of low energy in all eukaryotic cells. It is considered a key sensor of the balance of cellular ATP and AMP concentrations. LKB1 serine/threonine kinase is a divergent yet evolutionarily well-conserved kinase, biochemically sufficient to activate AMPK in vitro and genetically required for AMPK activation. Because of this potent connection to AMPK, LKB1 may act as a central regulator of metabolism in vivo. Once activated, AMP kinase phosphorylates the transcriptional activator TorC2, thereby blocking its nuclear translocation and inhibiting the expression of genes involved in gluconeogenesis. Data suggest that LKB1/AMPK signaling plays a role in protection from apoptosis, specifically in response to agents that increase the cellular AMP/ATP ratio. Active AMPK signaling offers a protective effect by providing the cell with time to reverse the aberrantly high ratio of AMP/ATP. If unable to reverse this ratio, the cell will eventually undergo cell death. These observations offer the provocative suggestion of a potential therapeutic window in which LKB1-deficient tumor cells may be acutely sensitive to AMP analogues or sensitized to cell death by other stimuli when treated in combination with agents that increase the AMP/ATP ratio. LKB1 therefore is a classical tumor suppressor. AMPK is a direct LKB1 substrate. A consequence of AMPK activation by LKB1 is the inhibition of the mammalian target of rapamycin (mTOR) C1 pathway. Metformin's anti-cancerous properties have been demonstrated in various cancer cells in vitro, such as lung, pancreatic, colon, ovarian, breast, prostate, renal cancer cells, melanoma, and even in acute lymphoblastic leukemia cells. To test metformin's action in vivo, mice were implanted with transformed mammary

  4. Metformin may protect nondiabetic breast cancer women from metastasis.

    PubMed

    El-Haggar, Sahar Mohammed; El-Shitany, Nagla A; Mostafa, Mohamed Farouk; El-Bassiouny, Noha Ahmed

    2016-04-01

    Metformin, a widely prescribed oral hypoglycemic agent, has recently received a big interest because of its potential antitumorigenic effects in different cancer types. The present study investigated the impact of adding metformin to breast cancer adjuvant therapy in nondiabetic women on, insulin like growth factor-1 (IGF-1), IGF binding protein-3 (IGFBP-3), insulin, fasting blood glucose (FBG), the molar ratio of IGF-1 to IGFBP-3, homeostatic model assessment of insulin resistance (HOMA-IR) and metastasis. 102 women with newly diagnosed breast cancer were divided into 2 main groups, a control group and a metformin group. All women were treated with adjuvant therapy, according to the protocols of Ministry of Health and Population and National Cancer Institute, Egypt. Moreover, the women in the metformin group received 850 mg of metformin twice daily. Blood samples were collected at baseline, after chemotherapy (CT), after 6 months of hormonal therapy (6-HT) and 12 months of hormonal therapy (12-HT) for analysis of serum IGF-1, IGFBP-3, insulin, FBG and cancer antigen 15-3 (CA15-3). Metformin resulted in a significant reduction of IGF-1, IGF-1: IGFBP-3 molar ratio, insulin, FBG and HOMA-IR. On the other hand, metformin caused a significant increase of IGFBP-3. Moreover, metformin significantly decreased the numbers of metastatic cases after 6-HT. Metformin may have potential antitumor and antimetastatic effects that need further clinical investigations. This may be attributed to either the significant increase of the apoptotic inducer IGFBP-3 or/and the significant reduction of mitogenic insulin, IGF-1, free bioactive IGF-1, FBG and HOMA-IR. PMID:26902691

  5. Metformin improves urine concentration in rodents with nephrogenic diabetes insipidus

    PubMed Central

    Efe, Orhan; Klein, Janet D.; LaRocque, Lauren M.; Ren, Huiwen; Sands, Jeff M.

    2016-01-01

    Urine concentration is regulated by vasopressin. Congenital nephrogenic diabetes insipidus (NDI) is caused by vasopressin type 2 receptor (V2R) mutations. We studied whether metformin could improve urine concentration in rodent models of congenital NDI by stimulating AMPK. To block the V2R in rats, tolvaptan (10 mg/kg/d) was given by oral gavage with or without metformin (800 mg/ kg/d). Control rats received vehicle with or without metformin. Tamoxifen-induced V2R KO mice were given metformin (600 mg/kg) or vehicle twice daily. Urine osmolality in tolvaptan-treated rats (1,303 ± 126 mOsM) was restored to control levels by metformin (2,335 ± 273 mOsM) within 3 days and was sustained for up to 10 days. Metformin increased protein abundance of inner medullary urea transporter UT-A1 by 61% and aquaporin 2 (AQP2) by 44% in tolvaptan-treated rats, and immunohistochemistry showed increased membrane accumulation of AQP2 with acute and chronic AMPK stimulation. Outer medullary Na+-K+-2Cl− cotransporter 2 (NKCC2) abundance increased (117%) with AMPK stimulation in control rats but not in V2R-blocked rats. Metformin increased V2R KO mouse urine osmolality within 3 hours, and the increase persisted for up to 12 hours. Metformin increased AQP2 in the V2R KO mice similar to the tolvaptan-treated rats. These results indicate that AMPK activators, such as metformin, might provide a promising treatment for congenital NDI. PMID:27478876

  6. Inhibition of lung tumorigenesis by metformin is associated with decreased plasma IGF-I and diminished receptor tyrosine kinase signaling

    PubMed Central

    Quinn, Brendan J.; Dallos, Matthew; Kitagawa, Hiroshi; Kunnumakkara, Ajaikumar B.; Memmott, Regan M.; Hollander, M. Christine; Gills, Joell J.; Dennis, Phillip A.

    2013-01-01

    Metformin is the most commonly prescribed drug for type II diabetes and is associated with decreased cancer risk. Previously, we showed that metformin prevented tobacco carcinogen (NNK)-induced lung tumorigenesis in a non-diabetic mouse model, which was associated with decreased IGF-I/insulin receptor signaling but not activation of AMPK in lung tissues, as well as decreased circulating levels of IGF-1 and insulin. Here, we used liver-IGF-1-deficient (LID) mice to determine the importance of IGF-1 in NNK-induced lung tumorigenesis and chemoprevention by metformin. LID mice had decreased lung tumor multiplicity and burden compared to WT mice. Metformin further decreased lung tumorigenesis in LID mice without affecting IGF-1 levels, suggesting that metformin can act through IGF-1-independent mechanisms. In lung tissues, metformin decreased phosphorylation of multiple receptor tyrosine kinases (RTKs) as well as levels of GTP-bound Ras independently of AMPK. Metformin also diminished plasma levels of several cognate ligands for these RTKs. Tissue distribution studies using [14C]-metformin showed that uptake of metformin was high in liver but 4 fold lower in lungs, suggesting that the suppression of RTK activation by metformin occurs predominantly via systemic, indirect effects. Systemic inhibition of circulating growth factors and local RTK signaling are new AMPK-independent mechanisms of action of metformin that could underlie its ability to prevent tobacco carcinogen-induced lung tumorigenesis. PMID:23771523

  7. Metformin elicits anticancer effects through the sequential modulation of DICER and c-MYC.

    PubMed

    Blandino, Giovanni; Valerio, Mariacristina; Cioce, Mario; Mori, Federica; Casadei, Luca; Pulito, Claudio; Sacconi, Andrea; Biagioni, Francesca; Cortese, Giancarlo; Galanti, Sergio; Manetti, Cesare; Citro, Gennaro; Muti, Paola; Strano, Sabrina

    2012-01-01

    Diabetic patients treated with metformin have a reduced incidence of cancer and cancer-related mortality. Here we show that metformin affects engraftment and growth of breast cancer tumours in mice. This correlates with the induction of metabolic changes compatible with clear anticancer effects. We demonstrate that microRNA modulation underlies the anticancer metabolic actions of metformin. In fact, metformin induces DICER expression and its effects are severely impaired in DICER knocked down cells. Conversely, ectopic expression of DICER recapitulates the effects of metformin in vivo and in vitro. The microRNAs upregulated by metformin belong mainly to energy metabolism pathways. Among the messenger RNAs downregulated by metformin, we found c-MYC, IRS-2 and HIF1alpha. Downregulation of c-MYC requires AMP-activated protein kinase-signalling and mir33a upregulation by metformin. Ectopic expression of c-MYC attenuates the anticancer metabolic effects of metformin. We suggest that DICER modulation, mir33a upregulation and c-MYC targeting have an important role in the anticancer metabolic effects of metformin. PMID:22643892

  8. Antihyperglycemic mechanism of metformin occurs via the AMPK/LXRα/POMC pathway

    PubMed Central

    Cho, Kumsun; Chung, Jae Yong; Cho, Sung Kweon; Shin, Hyun-Woo; Jang, In-Jin; Park, Jong-Wan; Yu, Kyung-Sang; Cho, Joo-Youn

    2015-01-01

    Metformin is a first-line drug for treating type 2 diabetes. Although metformin is known to phosphorylate AMP-activated protein kinase (AMPK), it is unclear how the glucose-lowering effect of metformin is related to AMPK activation. The aim of this study was to identify the urinary endogenous metabolites affected by metformin and to identify the novel underlying molecular mechanisms related to its anti-diabetic effect. Fourteen healthy male subjects were orally administered metformin (1000 mg) once. First morning urine samples were taken before and after administration to obtain metabolomic data. We then further investigated the anti-diabetic mechanism of metformin in vitro and in vivo. The fluctuation of the metabolite cortisol indicated that the neuroendocrine system was involved in the anti-diabetic effect of metformin. Actually we found that metformin induced AMPK/liver X receptor α (LXRα) phosphorylation, followed by pro-opiomelanocortin (POMC) suppression in rat pituitary cells. We confirmed this result by administering metformin in an animal study. Given that cortisol stimulates gluconeogenesis, we propose the anti-hyperglycemic effect of metformin is attributed to reduced POMC/adrenocorticotropic hormone (ACTH)/cortisol levels following AMPK/LXRα phosphorylation in the pituitaries. PMID:25634597

  9. Metformin impairs growth of endometrial cancer cells via cell cycle arrest and concomitant autophagy and apoptosis

    PubMed Central

    2014-01-01

    Background Effective therapies for early endometrial cancer usually involve surgical excision and consequent infertility Therefore, new treatment approaches that preserve fertility should be developed. Metformin, a well-tolerated anti-diabetic drug, can inhibit cancer cell growth. However, the mechanism of metformin action is not well understood. Here we investigate the roles of autophagy and apoptosis in the anti-cancer effects of metformin on endometrial cancer cells. Methods Ishikawa endometrial cancer cells were treated with metformin. WST-8 assays, colony formation assays, flow cytometry, caspase luminescence measurement, immunofluorescence, and western blots were used to assess the effects of metformin on cell viability, proliferation, cell cycle progression, apoptosis, and autophagy. Results Metformin-treated cells exhibited significantly lower viability and proliferation and significantly more cell cycle arrest in G1 and G2/M than control cells. These cells also exhibited significantly more apoptosis via both intrinsic and extrinsic pathways. In addition, metformin treatment induced autophagy. Inhibition of autophagy, either by Beclin1 knockdown or by 3-methyladenine-mediated inhibition of caspase-3/7, suppressed the anti-proliferative effects of metformin on endometrial cancer cells. These findings indicate that the anti-proliferative effects and apoptosis caused by metformin are partially or completely dependent on autophagy. Conclusions We showed that metformin suppresses endometrial cancer cell growth via cell cycle arrest and concomitant autophagy and apoptosis. PMID:24966801

  10. Urinary metabolomic profiling in mice with diet-induced obesity and type 2 diabetes mellitus after treatment with metformin, vildagliptin and their combination.

    PubMed

    Pelantová, Helena; Bugáňová, Martina; Holubová, Martina; Šedivá, Blanka; Zemenová, Jana; Sýkora, David; Kaválková, Petra; Haluzík, Martin; Železná, Blanka; Maletínská, Lenka; Kuneš, Jaroslav; Kuzma, Marek

    2016-08-15

    Metformin, vildagliptin and their combination are widely used for the treatment of diabetes, but little is known about the metabolic responses to these treatments. In the present study, NMR-based metabolomics was applied to detect changes in the urinary metabolomic profile of a mouse model of diet-induced obesity in response to these treatments. Additionally, standard biochemical parameters and the expression of enzymes involved in glucose and fat metabolism were monitored. Significant correlations were observed between several metabolites (e.g., N-carbamoyl-β-alanine, N1-methyl-4-pyridone-3-carboxamide, N1-methyl-2-pyridone-5-carboxamide, glucose, 3-indoxyl sulfate, dimethylglycine and several acylglycines) and the area under the curve of glucose concentrations during the oral glucose tolerance test. The present study is the first to present N-carbamoyl-β-alanine as a potential marker of type 2 diabetes mellitus and consequently to demonstrate the efficacies of the applied antidiabetic interventions. Moreover, the elevated acetate level observed after vildagliptin administration might reflect increased fatty acid oxidation. PMID:27164444

  11. Metformin Plays a Dual Role in MIN6 Pancreatic β Cell Function through AMPK-dependent Autophagy

    PubMed Central

    Jiang, Yingling; Huang, Wei; Wang, Jing; Xu, Zhipeng; He, Jieyu; Lin, Xiaohong; Zhou, Zhiguang; Zhang, Jingjing

    2014-01-01

    Metformin improves insulin sensitivity in insulin sensitive tissues such as liver, muscle and fat. However, the functional roles and the underlying mechanism of metformin action in pancreatic β cells remain elusive. Here we show that, under normal growth condition, metformin suppresses MIN6 β cell proliferation and promotes apoptosis via an AMPK-dependent and autophagy-mediated mechanism. On the other hand, metformin protects MIN6 cells against palmitic acid (PA)-induced apoptosis. Our findings indicate that metformin plays a dual role in β cell survival and overdose of this anti-diabetic drug itself may lead to potential β cell toxicity. PMID:24644425

  12. Management of type 2 diabetes mellitus with special reference to metformin therapy.

    PubMed

    Campbell, I W

    1991-05-01

    As monotherapy, metformin is similar to the sulphonylureas, in improving both fasting and post-prandial plasma glucose levels by approx. 25-30%. Metformin, unlike the sulphonylureas, does not promote insulin secretion and does not cause weight gain and is therefore preferable in obese NIDDM. Metformin is also of benefit as combined therapy with a sulphonylurea, and in older subjects the two drugs may give as good glycaemic control as insulin. Lactic acidosis with metformin is less common than sulphonylurea-induced hypoglycaemia although the mortality risk is similar. However, where both groups of drugs are properly used clinically, serious side-effects are unusual. Metformin may have a potential advantage in the management of NIDDM with hyperinsulinaemia in that it does not increase insulin levels. Where insulin levels have been compared in the same type II patients, metformin can achieve similar glycaemic control as a sulphonylurea (gliclazide) but with significantly lower plasma insulin levels. PMID:1936475

  13. Metformin inhibits lung cancer cells proliferation through repressing microRNA-222.

    PubMed

    Wang, Yuqi; Dai, Weimin; Chu, Xiangyang; Yang, Bo; Zhao, Ming; Sun, Yu'e

    2013-12-01

    Metformin, which is commonly used as an oral anti-hyperglycemic agent of the biguanide family, may reduce cancer risk and improve prognosis. However, the mechanism by which metformin affects various cancers, including lung cancer, remains unknown. MiR-222 induces cell growth and cell cycle progression via direct targeting of p27, p57 and PTEN in cancer cells. In the present study, we used A549 and NCI-H358 human lung cancer cell lines to study the effects and mechanisms of metformin. Metformin treatment reduced expression of miR-222 in these cells (p < 0.05). As a result, protein abundance of p27, p57 and PTEN were increased in cells exposed to metformin. Therefore, these data provide novel evidence for a mechanism that may contribute to the anti-neoplastic effects of metformin suggested by recent population studies and justifying further work to explore potential roles for it in lung cancer treatment. PMID:23974492

  14. Protective Effect of Metformin against Acute Inflammation and Oxidative Stress in Rat.

    PubMed

    Pandey, Abhimanu; Kumar, Vijay L

    2016-09-01

    Preclinical Research The antidiabetic drug, metformin, can inhibit the release of inflammatory mediators in several disease conditions. The present study was carried out to evaluate the efficacy of metformin in ameliorating edema formation, oxidative stress, mediator release and vascular changes associated with acute inflammation in the rat carrageenan model. Metformin dose-dependently inhibited paw swelling induced by carrageenan and normalized the tissue levels of the inflammatory markers myeloperoxidase and nitrite. It also maintained oxidative homeostasis as indicated by near normal levels of the oxidative stress markers glutathione, thiobarbituric acid reactive substances, catalase and superoxide dismutase. The histopathology of the paw tissue in metformin-treated animals was similar to that in normal paw and had similar effects to diclofenac. In a rat peritonitis model, metformin reduced vascular permeability and cellular infiltration. In conclusion, this study shows that metformin has a potential for use in treating various inflammatory conditions. PMID:27510757

  15. New targets of urocortin-mediated cardioprotection.

    PubMed

    Barry, Seán P; Lawrence, Kevin M; McCormick, James; Soond, Surinder M; Hubank, Mike; Eaton, Simon; Sivarajah, Ahila; Scarabelli, Tiziano M; Knight, Richard A; Thiemermann, Christoph; Latchman, David S; Townsend, Paul A; Stephanou, Anastasis

    2010-08-01

    The urocortin (UCN) hormones UCN1 and UCN2 have been shown previously to confer significant protection against myocardial ischaemia/reperfusion (I/R) injury; however, the molecular mechanisms underlying their action are poorly understood. To further define the transcriptional effect of UCNs that underpins their cardioprotective activity, a microarray analysis was carried out using an in vivo rat coronary occlusion model of I/R injury. Infusion of UCN1 or UCN2 before the onset of reperfusion resulted in the differential regulation of 66 and 141 genes respectively, the majority of which have not been described previously. Functional analysis demonstrated that UCN-regulated genes are involved in a wide range of biological responses, including cell death (e.g. X-linked inhibitor of apoptosis protein), oxidative stress (e.g. nuclear factor erythroid derived 2-related factor 1/nuclear factor erythroid derived 2-like 1) and metabolism (e.g. Prkaa2/AMPK). In addition, both UCN1 and UCN2 were found to modulate the expression of a host of genes involved in G-protein-coupled receptor (GPCR) signalling including Rac2, Gnb1, Dab2ip (AIP1), Ralgds, Rnd3, Rap1a and PKA, thereby revealing previously unrecognised signalling intermediates downstream of CRH receptors. Moreover, several of these GPCR-related genes have been shown previously to be involved in mitogen-activated protein kinase (MAPK) activation, suggesting a link between CRH receptors and induction of MAPKs. In addition, we have shown that both UCN1 and UCN2 significantly reduce free radical damage following myocardial infarction, and comparison of the UCN gene signatures with that of the anti-oxidant tempol revealed a significant overlap. These data uncover novel gene expression changes induced by UCNs, which will serve as a platform to further understand their mechanism of action in normal physiology and cardioprotection. PMID:20501665

  16. New targets of urocortin-mediated cardioprotection

    PubMed Central

    Barry, Seán P; Lawrence, Kevin M; McCormick, James; Soond, Surinder M; Hubank, Mike; Eaton, Simon; Sivarajah, Ahila; Scarabelli, Tiziano M; Knight, Richard A; Thiemermann, Christoph; Latchman, David S; Townsend, Paul A; Stephanou, Anastasis

    2010-01-01

    The urocortin (UCN) hormones UCN1 and UCN2 have been shown previously to confer significant protection against myocardial ischaemia/reperfusion (I/R) injury; however, the molecular mechanisms underlying their action are poorly understood. To further define the transcriptional effect of UCNs that underpins their cardioprotective activity, a microarray analysis was carried out using an in vivo rat coronary occlusion model of I/R injury. Infusion of UCN1 or UCN2 before the onset of reperfusion resulted in the differential regulation of 66 and 141 genes respectively, the majority of which have not been described previously. Functional analysis demonstrated that UCN-regulated genes are involved in a wide range of biological responses, including cell death (e.g. X-linked inhibitor of apoptosis protein), oxidative stress (e.g. nuclear factor erythroid derived 2-related factor 1/nuclear factor erythroid derived 2-like 1) and metabolism (e.g. Prkaa2/AMPK). In addition, both UCN1 and UCN2 were found to modulate the expression of a host of genes involved in G-protein-coupled receptor (GPCR) signalling including Rac2, Gnb1, Dab2ip (AIP1), Ralgds, Rnd3, Rap1a and PKA, thereby revealing previously unrecognised signalling intermediates downstream of CRH receptors. Moreover, several of these GPCR-related genes have been shown previously to be involved in mitogen-activated protein kinase (MAPK) activation, suggesting a link between CRH receptors and induction of MAPKs. In addition, we have shown that both UCN1 and UCN2 significantly reduce free radical damage following myocardial infarction, and comparison of the UCN gene signatures with that of the anti-oxidant tempol revealed a significant overlap. These data uncover novel gene expression changes induced by UCNs, which will serve as a platform to further understand their mechanism of action in normal physiology and cardioprotection. PMID:20501665

  17. Effect of metformin on Schwann cells under hypoxia condition

    PubMed Central

    Ma, Junxiong; Liu, Jun; Yu, Hailong; Chen, Yu; Wang, Qi; Xiang, Liangbi

    2015-01-01

    Metformin, which is the first-line drug for the treatment of diabetes mellitus type 2, has been proved to possess beneficial effects on nerve regeneration in many studies. However, the underlying mechanism is currently unclear. The present study was designed to investigate the potential beneficial effect of metformin on SCs under hypoxia condition, which is a biological process at the injury site. The cell number and cell viability of SCs were examined using fluorescence observation and MTT assay. The migration of SCs was evaluated using a Transwell chamber. The expression and secretion of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), glial cell derived neurotrophic factor (GDNF) and neural cell adhesion molecule (N-CAM) in SCs were assayed by RT-PCR and ELISA method. The results showed that metformin could help SCs recover from hypoxia injury and inhibit hypoxia-induced apoptosis. In addition, metformin could partially reverse the detrimental effect of hypoxia on cell number, viability, migration and adhesion. Metformin is also capable of maintaining the biological activities of SCs after hypoxia injury, such as increasing the expression and secretion of BDNF, NGF, GDNF, and N-CAM. Further studies showed that pre-incubation with AMPK (5’-AMP-activated protein kinase) inhibitor Compound C might partially inhibit the effect of metformin mentioned above, indicating the possible involvement of AMPK pathway in the beneficial effects of metformin on peripheral nervous system. In conclusion, metformin is capable of alleviating hypoxia-induced injury to SCs and AMPK pathway might be involved in this process. PMID:26261558

  18. Metformin does not enhance ovulation induction in clomiphene resistant polycystic ovary syndrome in clinical practice

    PubMed Central

    Sturrock, N D C; Lannon, B; Fay, T N

    2002-01-01

    Aims To determine whether metformin pretreatment has beneficial effects in clomiphene resistant infertile women with polycystic ovary syndrome (PCOS) in an infertility clinic. Methods This was a randomized placebo controlled double-blind crossover study of 3 months metformin (1500 mg day−1)/placebo, followed by 3 months metformin/placebo together with clomiphene (50–100 mg for 5 days) for three cycles in clomiphene resistant women with PCOS. The primary outcomes were restoration of spontaneous menses, ovulation induction (spontaneous or clomiphene induced) and pregnancy. Secondary endpoints were changes in biochemical parameters related to androgens and insulin. Results Twelve women completed the metformin arm and 14 the placebo arm. Spontaneous menstruation resumed in five metformin treated patients and in six placebo treated women, P = 0.63. No women given metformin spontaneously ovulated, although one patient given placebo did, P = 0.30. There was no difference in the efficacy of clomiphene between the two groups with ovulation being induced in five (out of 12) metformin treated women and four (out of 14) placebo treated women, P = 0.63. Pregnancy occurred in three (out of 12) women given metformin and two (out of 14) women given placebo, P = 0.59. Conclusions Metformin is not always beneficial when given to clomiphene resistant infertile women with PCOS in clinical practice. PMID:11994052

  19. Aspirin and atenolol enhance metformin activity against breast cancer by targeting both neoplastic and microenvironment cells.

    PubMed

    Talarico, Giovanna; Orecchioni, Stefania; Dallaglio, Katiuscia; Reggiani, Francesca; Mancuso, Patrizia; Calleri, Angelica; Gregato, Giuliana; Labanca, Valentina; Rossi, Teresa; Noonan, Douglas M; Albini, Adriana; Bertolini, Francesco

    2016-01-01

    Metformin can induce breast cancer (BC) cell apoptosis and reduce BC local and metastatic growth in preclinical models. Since Metformin is frequently used along with Aspirin or beta-blockers, we investigated the effect of Metformin, Aspirin and the beta-blocker Atenolol in several BC models. In vitro, Aspirin synergized with Metformin in inducing apoptosis of triple negative and endocrine-sensitive BC cells, and in activating AMPK in BC and in white adipose tissue (WAT) progenitors known to cooperate to BC progression. Both Aspirin and Atenolol added to the inhibitory effect of Metformin against complex I of the respiratory chain. In both immune-deficient and immune-competent preclinical models, Atenolol increased Metformin activity against angiogenesis, local and metastatic growth of HER2+ and triple negative BC. Aspirin increased the activity of Metformin only in immune-competent HER2+ BC models. Both Aspirin and Atenolol, when added to Metformin, significantly reduced the endothelial cell component of tumor vessels, whereas pericytes were reduced by the addition of Atenolol but not by the addition of Aspirin. Our data indicate that the addition of Aspirin or of Atenolol to Metformin might be beneficial for BC control, and that this activity is likely due to effects on both BC and microenvironment cells. PMID:26728433

  20. Aspirin and atenolol enhance metformin activity against breast cancer by targeting both neoplastic and microenvironment cells

    PubMed Central

    Talarico, Giovanna; Orecchioni, Stefania; Dallaglio, Katiuscia; Reggiani, Francesca; Mancuso, Patrizia; Calleri, Angelica; Gregato, Giuliana; Labanca, Valentina; Rossi, Teresa; Noonan, Douglas M.; Albini, Adriana; Bertolini, Francesco

    2016-01-01

    Metformin can induce breast cancer (BC) cell apoptosis and reduce BC local and metastatic growth in preclinical models. Since Metformin is frequently used along with Aspirin or beta-blockers, we investigated the effect of Metformin, Aspirin and the beta-blocker Atenolol in several BC models. In vitro, Aspirin synergized with Metformin in inducing apoptosis of triple negative and endocrine-sensitive BC cells, and in activating AMPK in BC and in white adipose tissue (WAT) progenitors known to cooperate to BC progression. Both Aspirin and Atenolol added to the inhibitory effect of Metformin against complex I of the respiratory chain. In both immune-deficient and immune-competent preclinical models, Atenolol increased Metformin activity against angiogenesis, local and metastatic growth of HER2+ and triple negative BC. Aspirin increased the activity of Metformin only in immune-competent HER2+ BC models. Both Aspirin and Atenolol, when added to Metformin, significantly reduced the endothelial cell component of tumor vessels, whereas pericytes were reduced by the addition of Atenolol but not by the addition of Aspirin. Our data indicate that the addition of Aspirin or of Atenolol to Metformin might be beneficial for BC control, and that this activity is likely due to effects on both BC and microenvironment cells. PMID:26728433

  1. Effect of the anti-diabetic drug metformin in hepatocellular carcinoma in vitro and in vivo.

    PubMed

    Miyoshi, Hisaaki; Kato, Kiyohito; Iwama, Hisakazu; Maeda, Emiko; Sakamoto, Teppei; Fujita, Koji; Toyota, Yuka; Tani, Joji; Nomura, Takako; Mimura, Shima; Kobayashi, Mitsuyoshi; Morishita, Asahiro; Kobara, Hideki; Mori, Hirohito; Yoneyama, Hirohito; Deguchi, Akihiro; Himoto, Takashi; Kurokohchi, Kazutaka; Okano, Keiichi; Suzuki, Yasuyuki; Murao, Koji; Masaki, Tsutomu

    2014-07-01

    Metformin is a commonly used oral anti-hyperglycemic agent of the biguanide family. Recent studies suggest that metformin may reduce cancer risk and improve prognosis. However, the antitumor mechanism of metformin in several types of cancers, including hepatocellular carcinoma (HCC), has not been elucidated. The goal of the present study was to evaluate the effects of metformin on HCC cell proliferation in vitro and in vivo, and to study microRNAs (miRNAs) associated with the antitumor effect of metformin in vitro. We used the cell lines Alex, HLE and Huh7, and normal hepatocytes to study the effects of metformin on human HCC cells. In an in vivo study, athymic nude mice bearing xenograft tumors were treated with metformin or left untreated. Tumor growth was recorded after 4 weeks, and the expression of cell cycle-related proteins was determined. Metformin inhibited the proliferation of Alex, HLE and Huh7 cells in vitro and in vivo. Metformin blocked the cell cycle in G0/G1 in vitro and in vivo. This blockade was accompanied by a strong decrease of G1 cyclins, especially cyclin D1, cyclin E and cyclin-dependent kinase 4 (Cdk4). In addition, microRNA (miRNA) expression was markedly altered by the treatment with metformin in vitro and in vivo. In addition, various miRNAs induced by metformin also may contribute to the suppression of tumor growth. Our results demonstrate that metformin inhibits the growth of HCC, possibly by inducing G1 cell cycle arrest through the alteration of microRNAs. PMID:24806290

  2. Regulation of Metformin Response by Breast Cancer Associated Gene 2123

    PubMed Central

    Buac, Daniela; Kona, Fathima R; Seth, Arun K; Dou, Q Ping

    2013-01-01

    Adenosine monophosphate-activated protein kinase (AMPK), a master regulator of cellular energy homeostasis, has emerged as a promising molecular target in the prevention of breast cancer. Clinical trials using the United States Food and Drug Administration (FDA)-approved, AMPK-activating, antidiabetic drug metformin are promising in this regard, but the question of why metformin is protective for some women but not others still remains. Breast cancer associated gene 2 (BCA2/Rabring7/RNF115), a novel Really Interesting New Gene (RING) finger ubiquitin E3 ligase, is overexpressed in >50% of breast tumors. Herein, we report that BCA2 is an endogenous inhibitor of AMPK activation in breast cancer cells and that BCA2 inhibition increases the efficacy of metformin. BCA2 overexpression inhibited both basal and inducible Thr172 phosphorylation/activation of AMPKα1, while BCA2-specific small interfering RNA (siRNA) enhanced phosphorylated AMPKα1 (pAMPKα1). The AMPK-suppressive function of BCA2 requires its E3 ligase-specific RING domain, suggesting that BCA2 targets some protein controlling (de)phosphorylation of AMPKα1 for degradation. Activation of AMPK by metformin triggered a growth inhibitory signal but also increased BCA2 protein levels, which correlated with AKT activation and could be curbed by an AMPK inhibitor, suggesting a potential feedback mechanism from pAMPKα1 to pAkt to BCA2. Finally, BCA2 siRNA, or inhibition of its upstream stabilizing kinase AKT, increased the growth inhibitory effect of metformin in multiple breast cancer cell lines, supporting the conclusion that BCA2 weakens metformin's efficacy. Our data suggest that metformin in combination with a BCA2 inhibitor may be a more effective breast cancer treatment strategy than metformin alone. PMID:24403860

  3. Delta Opioid Receptors: The Link between Exercise and Cardioprotection

    PubMed Central

    Borges, Juliana P.; Verdoorn, Karine S.; Daliry, Anissa; Powers, Scott K.; Ortenzi, Victor H.; Fortunato, Rodrigo S.; Tibiriçá, Eduardo; Lessa, Marcos Adriano

    2014-01-01

    This study investigated the role of opioid receptor (OR) subtypes as a mechanism by which endurance exercise promotes cardioprotection against myocardial ischemia-reperfusion (IR) injury. Wistar rats were randomly divided into one of seven experimental groups: 1) control; 2) exercise-trained; 3) exercise-trained plus a non-selective OR antagonist; 4) control sham; 5) exercise-trained plus a kappa OR antagonist; 6) exercise-trained plus a delta OR antagonist; and 7) exercise-trained plus a mu OR antagonist. The exercised animals underwent 4 consecutive days of treadmill training (60 min/day at ∼70% of maximal oxygen consumption). All groups except the sham group were exposed to an in vivo myocardial IR insult, and the myocardial infarct size (IS) was determined histologically. Myocardial capillary density, OR subtype expression, heat shock protein 72 (HSP72) expression, and antioxidant enzyme activity were measured in the hearts of both the exercised and control groups. Exercise training significantly reduced the myocardial IS by approximately 34%. Pharmacological blockade of the kappa or mu OR subtypes did not blunt exercise-induced cardioprotection against IR-mediated infarction, whereas treatment of animals with a non-selective OR antagonist or a delta OR antagonist abolished exercise-induced cardioprotection. Exercise training enhanced the activities of myocardial superoxide dismutase (SOD) and catalase but did not increase the left ventricular capillary density or the mRNA levels of HSP72, SOD, and catalase. In addition, exercise significantly reduced the protein expression of kappa and delta ORs in the heart by 44% and 37%, respectively. Together, these results indicate that ORs contribute to the cardioprotection conferred by endurance exercise, with the delta OR subtype playing a key role in this response. PMID:25415192

  4. Metformin Antagonizes Cancer Cell Proliferation by Suppressing Mitochondrial-Dependent Biosynthesis

    PubMed Central

    Griss, Takla; Vincent, Emma E.; Egnatchik, Robert; Chen, Jocelyn; Ma, Eric H.; Faubert, Brandon; Viollet, Benoit; DeBerardinis, Ralph J.; Jones, Russell G.

    2015-01-01

    Metformin is a biguanide widely prescribed to treat Type II diabetes that has gained interest as an antineoplastic agent. Recent work suggests that metformin directly antagonizes cancer cell growth through its actions on complex I of the mitochondrial electron transport chain (ETC). However, the mechanisms by which metformin arrests cancer cell proliferation remain poorly defined. Here we demonstrate that the metabolic checkpoint kinases AMP-activated protein kinase (AMPK) and LKB1 are not required for the antiproliferative effects of metformin. Rather, metformin inhibits cancer cell proliferation by suppressing mitochondrial-dependent biosynthetic activity. We show that in vitro metformin decreases the flow of glucose- and glutamine-derived metabolic intermediates into the Tricarboxylic Acid (TCA) cycle, leading to reduced citrate production and de novo lipid biosynthesis. Tumor cells lacking functional mitochondria maintain lipid biosynthesis in the presence of metformin via glutamine-dependent reductive carboxylation, and display reduced sensitivity to metformin-induced proliferative arrest. Our data indicate that metformin inhibits cancer cell proliferation by suppressing the production of mitochondrial-dependent metabolic intermediates required for cell growth, and that metabolic adaptations that bypass mitochondrial-dependent biosynthesis may provide a mechanism of tumor cell resistance to biguanide activity. PMID:26625127

  5. Metformin inhibits prostate cancer cell proliferation, migration, and tumor growth through upregulation of PEDF expression.

    PubMed

    Chen, Xiaowan; Li, Chenli; He, Tiantian; Mao, Jiating; Li, Chunmei; Lyu, Jianxin; Meng, Qing H

    2016-05-01

    Metformin has been reported to inhibit the growth of various types of cancers, including prostate cancer. Yet the mode of anti-cancer action of metformin and the underlying mechanisms remain not fully elucidated. We hypothesized that the antitumorigenic effects of metformin are mediated through upregulation of pigment epithelium-derived factor (PEDF) expression in prostate cancer cells. In this report, metformin treatment significantly inhibited the proliferation and colony formation of prostate cancer cells, in a dose- and time-dependent manner. Meanwhile, Metformin markedly suppressed migration and invasion and induced apoptosis of both LNCaP and PC3 cancer cells. Metformin also reduced PC3 tumor growth in BALB/c nude mice in vivo. Furthermore, metformin treatment was associated with higher PEDF expression in both prostate cancer cells and tumor tissue. Taken together, metformin inhibits prostate cancer cell proliferation, migration, invasion and tumor growth, and these activities are mediated by upregulation of PEDF expression. These findings provide a novel insight into the molecular functions of metformin as an anticancer agent. PMID:26987032

  6. Metformin Promotes Apoptosis but Suppresses Autophagy in Glucose-Deprived H4IIE Hepatocellular Carcinoma Cells

    PubMed Central

    2015-01-01

    Background Metformin, a well-known anti-diabetic drug, has gained interest due to its association with the reduction of the prevalence of cancer in patients with type 2 diabetes and the anti-proliferative effect of metformin in several cancer cells. Here, we investigated the anti-proliferative effect of metformin with respect to apoptosis and autophagy in H4IIE hepatocellular carcinoma cells. Methods H4IIE rat cells were treated with metformin in glucose-free medium for 24 hours and were then subjected to experiments examining the onset of apoptosis and/or autophagy as well as the related signaling pathways. Results When H4IIE cells were incubated in glucose-free media for 24 hours, metformin and 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) reduced the viability of cells. Inhibition of AMP-activated protein kinase (AMPK) by compound C significantly blocked cell death induced by metformin or AICAR. Pro-apoptotic events (nuclear condensation, hydrolysis of intact poly ADP ribose polymerase and caspase-3) were stimulated by metformin and then suppressed by compound C. Interestingly, the formation of acidic intracellular vesicles, a marker of autophagy, was stimulated by compound C. Although the deprivation of amino acids in culture media also induced apoptosis, neither metformin nor compound C affected cell viability. The expression levels of all of the autophagy-related proteins examined decreased with metformin, and two proteins (light chain 3 and beclin-1) were sensitive to compound C. Among the tested inhibitors against MAP kinases and phosphatidylinositol-3-kinase/mammalian target of rapamycin, SB202190 (against p38MAP kinase) significantly interrupted the effects of metformin. Conclusion Our data suggest that metformin induces apoptosis, but suppresses autophagy, in hepatocellular carcinoma cells via signaling pathways, including AMPK and p38 mitogen-activated protein kinase. PMID:26706918

  7. The cardioprotective power of leaves

    PubMed Central

    Boncler, Magdalena; Watala, Cezary

    2015-01-01

    Lack of physical activity, smoking and/or inappropriate diet can contribute to the increase of oxidative stress, in turn affecting the pathophysiology of cardiovascular diseases. Strong anti-oxidant properties of plant polyphenolic compounds might underlie their cardioprotective activity. This paper reviews recent findings on the anti-oxidant activity of plant leaf extracts and emphasizes their effects on blood platelets, leukocytes and endothelial cells – the targets orchestrating the development and progression of cardiovascular diseases. We also review the evidence linking supplementation with plant leaf extracts and the risk factors defining the metabolic syndrome. The data point to the importance of leaves as an alternative source of polyphenolic compounds in the human diet and their role in the prevention of cardiovascular diseases. PMID:26322095

  8. Sphingosine kinase regulation and cardioprotection

    PubMed Central

    Karliner, Joel S.

    2009-01-01

    Activation of sphingosine kinase/sphingosine-1-phosphate (SK/S1P)-mediated signalling has been recognized as critical for cardioprotection in response to acute ischaemia/reperfusion injury. Incubation of S1P with cultured cardiac myocytes subjected to hypoxia or treatment of isolated hearts either before ischaemia or at the onset of reperfusion (pharmacologic pre- or postconditioning) results in reduced myocyte injury. Synthetic agonists active at S1P receptors mimic these responses. Gene-targeted mice null for the SK1 isoform whose hearts are subjected to ischaemia/reperfusion injury exhibit increased infarct size and respond poorly either to ischaemic pre- or postconditioning. Measurements of cardiac SK activity and S1P parallel these observations. Ischaemic postconditioning combined with sphingosine and S1P rescues the heart from prolonged ischaemia. These observations may have considerable relevance for future therapeutic approaches to acute and chronic myocardial injury. PMID:19017750

  9. Metformin Prevents Nigrostriatal Dopamine Degeneration Independent of AMPK Activation in Dopamine Neurons

    PubMed Central

    Bayliss, Jacqueline A.; Lemus, Moyra B.; Santos, Vanessa V.; Deo, Minh; Davies, Jeffrey S.; Kemp, Bruce E.; Elsworth, John D.

    2016-01-01

    Metformin is a widely prescribed drug used to treat type-2 diabetes, although recent studies show it has wide ranging effects to treat other diseases. Animal and retrospective human studies indicate that Metformin treatment is neuroprotective in Parkinson’s Disease (PD), although the neuroprotective mechanism is unknown, numerous studies suggest the beneficial effects on glucose homeostasis may be through AMPK activation. In this study we tested whether or not AMPK activation in dopamine neurons was required for the neuroprotective effects of Metformin in PD. We generated transgenic mice in which AMPK activity in dopamine neurons was ablated by removing AMPK beta 1 and beta 2 subunits from dopamine transporter expressing neurons. These AMPK WT and KO mice were then chronically exposed to Metformin in the drinking water then exposed to MPTP, the mouse model of PD. Chronic Metformin treatment significantly attenuated the MPTP-induced loss of Tyrosine Hydroxylase (TH) neuronal number and volume and TH protein concentration in the nigrostriatal pathway. Additionally, Metformin treatment prevented the MPTP-induced elevation of the DOPAC:DA ratio regardless of genotype. Metformin also prevented MPTP induced gliosis in the Substantia Nigra. These neuroprotective actions were independent of genotype and occurred in both AMPK WT and AMPK KO mice. Overall, our studies suggest that Metformin’s neuroprotective effects are not due to AMPK activation in dopaminergic neurons and that more research is required to determine how metformin acts to restrict the development of PD. PMID:27467571

  10. Isoflurane Preconditioning Confers Cardioprotection by Activation of ALDH2

    PubMed Central

    Lang, Xiao-E; Wang, Xiong; Zhang, Ke-Rang; Lv, Ji-Yuan; Jin, Jian-Hua; Li, Qing-Shan

    2013-01-01

    The volatile anesthetic, isoflurane, protects the heart from ischemia/reperfusion (I/R) injury. Aldehyde dehydrogenase 2 (ALDH2) is thought to be an endogenous mechanism against ischemia-reperfusion injury possibly through detoxification of toxic aldehydes. We investigated whether cardioprotection by isoflurane depends on activation of ALDH2.Anesthetized rats underwent 40 min of coronary artery occlusion followed by 120 min of reperfusion and were randomly assigned to the following groups: untreated controls, isoflurane preconditioning with and without an ALDH2 inhibitor, the direct activator of ALDH2 or a protein kinase C (PKCε) inhibitor. Pretreatment with isoflurane prior to ischemia reduced LDH and CK-MB levels and infarct size, while it increased phosphorylation of ALDH2, which could be blocked by the ALDH2 inhibitor, cyanamide. Isolated neonatal cardiomyocytes were treated with hypoxia followed by reoxygenation. Hypoxia/reoxygenation (H/R) increased cardiomyocyte apoptosis and injury which were attenuated by isoflurane and forced the activation of ALDH2. In contrast, the effect of isoflurane-induced protection was almost abolished by knockdown of ALDH2. Activation of ALDH2 and cardioprotection by isoflurane were substantially blocked by the PKCε inhibitor. Activation of ALDH2 by mitochondrial PKCε plays an important role in the cardioprotection of isoflurane in myocardium I/R injury. PMID:23468836

  11. Comparative evaluation of the therapeutic effect of metformin monotherapy with metformin and acupuncture combined therapy on weight loss and insulin sensitivity in diabetic patients

    PubMed Central

    Firouzjaei, A; Li, G-C; Wang, N; Liu, W-X; Zhu, B-M

    2016-01-01

    Objective: Obesity induces insulin resistance (IR), the key etiologic defect of type 2 diabetes mellitus (T2DM). Therefore, an incidence of obesity-induced diabetes is expected to decrease if obesity is controlled. Although Metformin is currently one of the main treatment options for T2DM in obese patients, resulting in an average of 5% weight loss, adequate weight control in all patients cannot be achieved with Metformin alone. Thus, additional therapies with a weight loss effect, such as acupuncture, may improve the effectiveness of Metformin. Subjective: We designed this randomized clinical trial (RCT) to compare the effects of Metformin monotherapy with that of Metformin and acupuncture combined therapy on weight loss and insulin sensitivity among overweight/obese T2DM patients, to understand whether acupuncture plus Metformin is a better approach than Metformin only on treating diabetes. To understand whether acupuncture can be an insulin sensitizer and, if so, its therapeutic mechanism. Results: Our results show that Metformin and acupuncture combined therapy significantly improves body weight, body mass index (BMI), fasting blood sugar (FBS), fasting insulin (FINS), homeostasis model assessment (HOMA) index, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), leptin, adiponectin, glucagon-like peptide-1 (GLP-1), resistin, serotonin, free fatty acids (FFAs), triglyceride (TG), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc) and ceramides. Conclusions: Consequently, Metformin and acupuncture combined therapy is more effective than Metformin only, proving that acupuncture is an insulin sensitizer and is able to improve insulin sensitivity possibly by reducing body weight and inflammation, while improving lipid metabolism and adipokines. As a result, electro-acupuncture (EA) might be useful in controlling the ongoing epidemics in obesity and T2DM. PMID:27136447

  12. O-carboxymethyl chitosan nanoparticles for metformin delivery to pancreatic cancer cells.

    PubMed

    Snima, K S; Jayakumar, R; Unnikrishnan, A G; Nair, Shantikumar V; Lakshmanan, Vinoth-Kumar

    2012-07-01

    In this work we developed metformin loaded O-carboxymethyl chitosan (O-CMC) nanoparticles (NPs) by ionic-gelation method. The prepared NPs of 240 ± 50 nm size with spherical morphology exhibited a pH sensitive release of metformin in vitro. Cytotoxicity studies showed that the drug-incorporated NPs induced significant toxicity on pancreatic cancer cells (MiaPaCa-2) compared to normal cells (L929). Metformin loaded NPs exhibited nonspecific internalization by normal and pancreatic cancer cells; however metformin released from the NPs induced preferential toxicity on pancreatic cancer cells. Our preliminary studies suggested that such a novel approach could possibly overcome the current limitations of metformin in its clinical application against pancreatic cancer. PMID:24750892

  13. Effects of Metformin on Tissue Oxidative and Dicarbonyl Stress in Transgenic Spontaneously Hypertensive Rats Expressing Human C-Reactive Protein.

    PubMed

    Malínská, Hana; Oliyarnyk, Olena; Škop, Vojtěch; Šilhavý, Jan; Landa, Vladimír; Zídek, Václav; Mlejnek, Petr; Šimáková, Miroslava; Strnad, Hynek; Kazdová, Ludmila; Pravenec, Michal

    2016-01-01

    -activated protein kinase (AMPK) signaling and gluconeogenesis pathways. It can be concluded that in the presence of high levels of human CRP, metformin protects against inflammation and oxidative and dicarbonyl stress in the heart, but not in the kidney. Accordingly, these cardioprotective effects of metformin might be especially effective in diabetic patients with high levels of CRP. PMID:26963617

  14. Effects of Metformin on Tissue Oxidative and Dicarbonyl Stress in Transgenic Spontaneously Hypertensive Rats Expressing Human C-Reactive Protein

    PubMed Central

    Malínská, Hana; Oliyarnyk, Olena; Škop, Vojtěch; Šilhavý, Jan; Landa, Vladimír; Zídek, Václav; Mlejnek, Petr; Šimáková, Miroslava; Strnad, Hynek; Kazdová, Ludmila; Pravenec, Michal

    2016-01-01

    -activated protein kinase (AMPK) signaling and gluconeogenesis pathways. It can be concluded that in the presence of high levels of human CRP, metformin protects against inflammation and oxidative and dicarbonyl stress in the heart, but not in the kidney. Accordingly, these cardioprotective effects of metformin might be especially effective in diabetic patients with high levels of CRP. PMID:26963617

  15. Metformin activates a duodenal Ampk-dependent pathway to lower hepatic glucose production in rats.

    PubMed

    Duca, Frank A; Côté, Clémence D; Rasmussen, Brittany A; Zadeh-Tahmasebi, Melika; Rutter, Guy A; Filippi, Beatrice M; Lam, Tony K T

    2015-05-01

    Metformin is a first-line therapeutic option for the treatment of type 2 diabetes, even though its underlying mechanisms of action are relatively unclear. Metformin lowers blood glucose levels by inhibiting hepatic glucose production (HGP), an effect originally postulated to be due to a hepatic AMP-activated protein kinase (AMPK)-dependent mechanism. However, studies have questioned the contribution of hepatic AMPK to the effects of metformin on lowering hyperglycemia, and a gut-brain-liver axis that mediates intestinal nutrient- and hormone-induced lowering of HGP has been identified. Thus, it is possible that metformin affects HGP through this inter-organ crosstalk. Here we show that intraduodenal infusion of metformin for 50 min activated duodenal mucosal Ampk and lowered HGP in a rat 3 d high fat diet (HFD)-induced model of insulin resistance. Inhibition of duodenal Ampk negated the HGP-lowering effect of intraduodenal metformin, and both duodenal glucagon-like peptide-1 receptor (Glp-1r)-protein kinase A (Pka) signaling and a neuronal-mediated gut-brain-liver pathway were required for metformin to lower HGP. Preabsorptive metformin also lowered HGP in rat models of 28 d HFD-induced obesity and insulin resistance and nicotinamide (NA)-streptozotocin (STZ)-HFD-induced type 2 diabetes. In an unclamped setting, inhibition of duodenal Ampk reduced the glucose-lowering effects of a bolus metformin treatment in rat models of diabetes. These findings show that, in rat models of both obesity and diabetes, metformin activates a previously unappreciated duodenal Ampk-dependent pathway to lower HGP and plasma glucose levels. PMID:25849133

  16. Metformin potentiates rapamycin and cisplatin in gastric cancer in mice

    PubMed Central

    Gao, Yunshu; Jiao, Xiaodong; Huang, Suyun; Wang, Jiejun; Li, Zhaosheng; Xie, Keping

    2015-01-01

    Here we showed that pAMPKα and PTEN were down-regulated and p-mTOR, p-S6, p-4EBP1, MMP7, and DCN1 were up-regulated in human gastric cancer tissue samples as compared to that in the noncancerous tissues. Metformin inhibited tumor growth in mice. Also it enhanced cisplatin- or rapamycin-induced reduction of tumor growth as compared with treatment of either drug alone. In addition to activation of AMPK and suppression of the mTOR pathway, a series of increased and decreased genes expression were induced by metformin, including PTEN, MMP7, and FN1. We suggest that metformin could potentially be used for the treatment of gastric cancer especially in combination with cisplatin or rapamycin. PMID:25909163

  17. Oxytocin and cardioprotection in diabetes and obesity.

    PubMed

    Jankowski, Marek; Broderick, Tom L; Gutkowska, Jolanta

    2016-01-01

    Oxytocin (OT) emerges as a drug for the treatment of diabetes and obesity. The entire OT system is synthesized in the rat and human heart. The direct myocardial infusion with OT into an ischemic or failing heart has the potential to elicit a variety of cardioprotective effects. OT treatment attenuates cardiomyocyte (CMs) death induced by ischemia-reperfusion by activating pro-survival pathways within injured CMs in vivo and in isolated cells. OT treatment reduces cardiac apoptosis, fibrosis, and hypertrophy. The OT/OT receptor (OTR) system is downregulated in the db/db mouse model of type 2 diabetes which develops genetic diabetic cardiomyopathy (DC) similar to human disease. We have shown that chronic OT treatment prevents the development of DC in the db/db mouse. In addition, OT stimulates glucose uptake in both cardiac stem cells and CMs, and increases cell resistance to diabetic conditions. OT may help replace lost CMs by stimulating the in situ differentiation of cardiac stem cells into functional mature CMs. Lastly, adult stem cells amenable for transplantation such as MSCs could be preconditioned with OT ex vivo and implanted into the injured heart to aid in tissue regeneration through direct differentiation, secretion of protective and cardiomyogenic factors and/or their fusion with injured CMs. PMID:27268060

  18. Effects of metformin on intestinal 5-hydroxytryptamine (5-HT) release and on 5-HT3 receptors.

    PubMed

    Cubeddu, L X; Bönisch, H; Göthert, M; Molderings, G; Racké, K; Ramadori, G; Miller, K J; Schwörer, H

    2000-01-01

    Nearly 30% of patients treated with metformin experience gastrointestinal side effects. Since release of 5-hydroxytryptamine (5-HT) from the intestine is associated with nausea, vomiting, and diarrhea, we examined whether metformin induces 5-HT release from the intestinal mucosa. In 40% of tissue biopsy specimens of human duodenal mucosa, metformin (1, 10, and 30 microM) caused an increase in 5-HT outflow by 35, 70, and 98%, respectively. Peak increases in 5-HT outflow were observed after 10-15 min exposure to metformin, returning to baseline levels after 25 min. Tetrodotoxin (1 microM) reduced by about 50% the metformin-evoked increase in 5-HT outflow (P<0.05). Metformin-evoked release was not affected by scopolamine + hexamethonium, propranolol, the 5-HT3 receptor antagonist dolasetron, naloxone, or the NK1 receptor antagonist L703606. In the presence of tetrodotoxin (1 microM), somatostatin (1 microM) further reduced metformin-induced 5-HT release by 15-20%. In view of the 5-HT releasing effects of selective 5-HT3 receptor agonists to which metformin (N-N-dimethylbiguanide) is structurally related, we investigated whether metformin directly interacts with 5-HT3 receptors. Receptor binding (inhibition of [3H]-GR65630 binding) and agonist effects (stimulation of [14C]-guanidinium influx) at 5-HT3 receptors were studied in murine neuroblastoma N1E-115 cells, which express functional 5-HT3 receptors. Metformin up to 0.3 mM failed to inhibit [3H]-GR65630 binding and to modify displacement of [3H]-GR65630 binding induced by 5-HT. 5-HT (3 microM) stimulated the influx of [14C]-guanidinium in intact N1E-115 cells. Metformin up to 1 mM failed to modify basal influx, 5-HT-induced influx, and 5-HT+ substance P-induced influx of [14C]-guanidinium. Our results indicate that metformin induces 5-HT3 receptor-independent release of 5-HT from human duodenal mucosa via neuronal and non-neuronal mechanisms. Part of the gastrointestinal side effects observed during treatment with

  19. Metformin inhibits ovarian cancer growth and increases sensitivity to paclitaxel in mouse models

    PubMed Central

    LENGYEL, Ernst; LITCHFIELD, Lacey M.; MITRA, Anirban K.; NIEMAN, Kristin M.; MUKHERJEE, Abir; ZHANG, Yilin; JOHNSON, Alyssa; BRADARIC, Michael; LEE, WooSeok; ROMERO, Iris L.

    2014-01-01

    OBJECTIVE There is increasing pre-clinical evidence indicating that metformin, a medication commonly used for type 2 diabetes, may protect against cancer. Motivated by this emerging evidence we asked two questions: (a) can metformin prevent ovarian cancer growth by altering metabolism, and (b) will metformin increase sensitivity to chemotherapy. STUDY DESIGN The effect of metformin in ovarian cancer was tested in vitro and by using two different mouse models. In vitro, cell lines (n=6) were treated with metformin (10 to 40 mM) or PBS and cellular proliferation and metabolic alterations (AMP-activated protein kinase activity, glycolysis, lipid synthesis) were compared between the two groups. In mouse models, a prevention study was performed by treating mice with metformin (250 mg/kg/day intraperitoneal (i.p.)) or placebo for 2 weeks followed by i.p. injection of the SKOV3ip1 human ovarian cancer cell line and the mean number of tumor implants in each treatment group was compared. In a treatment study, the LSL-K-rasG12D/+/PTENfloxP/floxP genetic mouse model of ovarian cancer was used. Mice were treated with placebo, paclitaxel (3 mg/kg/week i.p. x 7 weeks), metformin (100 mg/kg/day in water x 7 weeks), or paclitaxel plus metformin and tumor volume was compared between treatment groups. RESULTS In vitro, metformin decreased proliferation of ovarian cancer cell lines and induced cell cycle arrest, but not apoptosis. Further analysis showed that metformin altered several aspects of metabolism including AMP-activated protein kinase activity, glycolysis, and lipid synthesis. In the prevention mouse model, mice pre-treated with metformin had 60 % fewer tumor implants compared to controls (p<0.005). In the treatment study, mice treated with paclitaxel plus metformin had a 60% reduction in tumor weight compared to controls (p=0.02); a level of tumor reduction greater than that resulting from either paclitaxel or metformin alone. CONCLUSION Based on these results, we conclude

  20. Metformin Targets the Metabolic Achilles Heel of Human Pancreatic Cancer Stem Cells

    PubMed Central

    Sancho, Patricia; Sanchez-Ripoll, Yolanda; Trabulo, Sara Maria; Dorado, Jorge; Balic, Anamaria; Hidalgo, Manuel; Heeschen, Christopher

    2013-01-01

    Pancreatic ductal adenocarcinomas contain a subset of exclusively tumorigenic cancer stem cells (CSCs), which are capable of repopulating the entire heterogeneous cancer cell populations and are highly resistant to standard chemotherapy. Here we demonstrate that metformin selectively ablated pancreatic CSCs as evidenced by diminished expression of pluripotency-associated genes and CSC-associated surface markers. Subsequently, the ability of metformin-treated CSCs to clonally expand in vitro was irreversibly abrogated by inducing apoptosis. In contrast, non-CSCs preferentially responded by cell cycle arrest, but were not eliminated by metformin treatment. Mechanistically, metformin increased reactive oxygen species production in CSC and reduced their mitochondrial transmembrane potential. The subsequent induction of lethal energy crisis in CSCs was independent of AMPK/mTOR. Finally, in primary cancer tissue xenograft models metformin effectively reduced tumor burden and prevented disease progression; if combined with a stroma-targeting smoothened inhibitor for enhanced tissue penetration, while gemcitabine actually appeared dispensable. PMID:24204632

  1. Cardioprotection by ranolazine in perfused rat heart.

    PubMed

    Ghelardoni, Sandra; Chiellini, Grazia; Frascarelli, Sabina; Zucchi, Riccardo

    2014-12-01

    : We used the isolated working rat model to evaluate the effect of therapeutic concentrations (5-10 μM) of ranolazine on contractile performance, oxygen consumption, irreversible ischemic injury, and sarcoplasmic reticulum (SR) function. Ischemic injury was induced by 30 minutes of global ischemia followed by 120 minutes of Langendorff reperfusion and evaluated on the basis of triphenyltetrazolium chloride staining. SR function was determined on the basis of [H]-ryanodine binding, the kinetics of calcium-induced calcium release, measured by quick filtration technique, and oxalate-supported calcium uptake. In working hearts, ranolazine significantly reduced oxygen consumption (P = 0.031), in the absence of significant changes in contractile performance, and decreased irreversible ischemic injury (P = 0.011), if administered either before ischemia-reperfusion (25.4% ± 4.7% vs. 42.7% ± 6.0%) or only at the time of reperfusion (20.2% ± 5.2% vs. 43.7% ± 9.9%). In SR experiments, treatment with ranolazine determined a significant reduction in [H]-ryanodine binding (P = 0.029), because of decreased binding site density (369 ± 9 vs. 405 ± 12 fmol/mg), and in the kinetics of SR calcium release (P = 0.011), whose rate constant was decreased, whereas active calcium uptake was not affected. Ranolazine effectiveness at reperfusion and its ability to module SR calcium release suggest that this drug might be particularly useful to induce cardioprotection during coronary revascularization interventions, although the relevance of the effects on calcium homeostasis remains to be determined. PMID:25490416

  2. Prospects for Creation of Cardioprotective Drugs Based on Cannabinoid Receptor Agonists.

    PubMed

    Maslov, Leonid N; Khaliulin, Igor; Zhang, Yi; Krylatov, Andrey V; Naryzhnaya, Natalia V; Mechoulam, Raphael; De Petrocellis, Luciano; Downey, James M

    2016-05-01

    Cannabinoids can mimic the infarct-reducing effect of early ischemic preconditioning, delayed ischemic preconditioning, and ischemic postconditioning against myocardial ischemia/reperfusion. They do this primarily through both CB1 and CB2 receptors. Cannabinoids are also involved in remote preconditioning of the heart. The cannabinoid receptor ligands also exhibit an antiapoptotic effect during ischemia/reperfusion of the heart. The acute cardioprotective effect of cannabinoids is mediated by activation of protein kinase C, extracellular signal-regulated kinase, and p38 kinase. The delayed cardioprotective effect of cannabinoid anandamide is mediated via stimulation of phosphatidylinositol-3-kinase-Akt signaling pathway and enhancement of heat shock protein 72 expression. The delayed cardioprotective effect of another cannabinoid, Δ9-tetrahydrocannabinol, is associated with augmentation of nitric oxide (NO) synthase expression, but data on the involvement of NO synthase in the acute cardioprotective effect of cannabinoids are contradictory. The adenosine triphosphate-sensitive K(+)channel is involved in the synthetic cannabinoid HU-210-induced cardiac resistance to ischemia/reperfusion injury. Cannabinoids inhibit Na(+)/Ca(2+)exchange via peripheral cannabinoid receptor (CB2) activation that may also be related to the antiapoptotic and cardioprotective effects of cannabinoids. The cannabinoid receptor agonists should be considered as prospective group of compounds for creation of drugs that are able to protect the heart against ischemia-reperfusion injury in the clinical setting. PMID:26487546

  3. [Cardioprotective effect of GABA derivatives in acute alcohol intoxication].

    PubMed

    Perfilova, V N; Tiurenkov, I N; Berestovitskaia, V M; Vasil'eva, O S

    2006-01-01

    Cardioprotective properties of GABA analogs under conditions of acute alcoholic intoxication have been studied using the following functional tests: volume loads, tests for adrenoreactivity, and maximum isometric load. The experiments showed that a 32% aqueous ethanol solution intraperitoneally injected in a dose of 8 g/kg produces a cardiotoxic action, which is manifested by a decrease in the inotropic reserve in load tests. Citrocard (50 mg/kg), phenibut (50 mg/kg), and piracetam (200 mg/kg) prevent the alcohol-induced myocardium injury, as shown by the heart contractility retained on a higher level in the test group than in the control group. PMID:16995433

  4. Noble gases as cardioprotectants – translatability and mechanism

    PubMed Central

    Smit, Kirsten F; Weber, Nina C; Hollmann, Markus W; Preckel, Benedikt

    2015-01-01

    Several noble gases, although classified as inert substances, exert a tissue-protective effect in different experimental models when applied before organ ischaemia as an early or late preconditioning stimulus, after ischaemia as a post-conditioning stimulus or when given in combination before, during and/or after ischaemia. A wide range of organs can be protected by these inert substances, in particular cardiac and neuronal tissue. In this review we summarize the data on noble gas-induced cardioprotection, focusing on the underlying protective mechanisms. We will also look at translatability of experimental data to the clinical situation. PMID:25363501

  5. Spinal Neuronal NOS Signaling Contributes to Morphine Cardioprotection in Ischemia Reperfusion Injury in Rats.

    PubMed

    Jiang, Lingling; Hu, Jun; He, Shufang; Zhang, Li; Zhang, Ye

    2016-09-01

    Morphine has been widely used as rescue treatment for heart attack and failure in humans for many decades. Relatively little has been known about the role of spinal opioid receptors in morphine cardioprotection. Recent studies have shown that intrathecal injection of morphine can reduce the heart injury caused by ischemia (I)/reperfusion (R) in rats. However, the molecular and cellular mechanisms underlying intrathecal morphine cardioprotection has not been determined. Here, we report that intrathecal morphine postconditioning (IMPOC) rescued mean artery pressure (MAP) and reduced myocardial injury in I/R. Pretreatment with either naloxone (NAL), a selective mu-opioid receptor antagonist, or nitric oxide synthase (NOS) inhibitors via intrathecal delivery completely abolished IMPOC cardioprotection, suggesting that the spinal mu-opioid receptor and its downstream NOS signaling pathway are involved in the mechanism of the morphine-induced effect. Consistent with this, IMPOC significantly enhanced spinal neural NOS phosphorylation, nitric oxide, and cGMP content in a similar time course. Intrathecal application of 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a specific inhibitor of guanylate cyclase, completely ablated IMPOC-induced enhancement of cardioprotection and spinal cGMP content. IMPOC rescue of MAP and ischemic injury is correlated with IMPOC enhancement of NOS signaling. Collectively, these findings strengthen the concept of spinal mu-opioid receptors as a therapeutic target that mediates morphine-induced cardioprotection. We also provide evidence suggesting that the activation of spinal NOS signaling is essential for morphine cardioprotection. PMID:27358482

  6. Metformin alleviates hepatosteatosis by restoring SIRT1-mediated autophagy induction via an AMP-activated protein kinase-independent pathway

    PubMed Central

    Song, Young Mi; Lee, Yong-ho; Kim, Ji-Won; Ham, Dong-Sik; Kang, Eun-Seok; Cha, Bong Soo; Lee, Hyun Chul; Lee, Byung-Wan

    2014-01-01

    Metformin activates both PRKA and SIRT1. Furthermore, autophagy is induced by either the PRKA-MTOR-ULK1 or SIRT1-FOXO signaling pathways. We aimed to elucidate the mechanism by which metformin alleviates hepatosteatosis by examining the molecular interplay between SIRT1, PRKA, and autophagy. ob/ob mice were divided into 3 groups: one with ad libitum feeding of a standard chow diet, one with 300 mg/kg intraperitoneal metformin injections, and one with 3 g/d caloric restriction (CR) for a period of 4 wk. Primary hepatocytes or HepG2 cells were treated with oleic acid (OA) plus high glucose in the absence or presence of metformin. Both CR and metformin significantly improved body weight and glucose homeostasis, along with hepatic steatosis, in ob/ob mice. Furthermore, CR and metformin both upregulated SIRT1 expression and also stimulated autophagy induction and flux in vivo. Metformin also prevented OA with high glucose-induced suppression of both SIRT1 expression and SIRT1-dependent activation of autophagy machinery, thereby alleviating intracellular lipid accumulation in vitro. Interestingly, metformin treatment upregulated SIRT1 expression and activated PRKA even after siRNA-mediated knockdown of PRKAA1/2 and SIRT1, respectively. Taken together, these results suggest that metformin alleviates hepatic steatosis through PRKA-independent, SIRT1-mediated effects on the autophagy machinery. PMID:25484077

  7. Effect of the anti-diabetic drug metformin in hepatocellular carcinoma in vitro and in vivo.

    PubMed

    Miyoshi, Hisaaki; Kato, Kiyohito; Iwama, Hisakazu; Maeda, Emiko; Sakamoto, Teppei; Fujita, Koji; Toyota, Yuka; Tani, Joji; Nomura, Takako; Mimura, Shima; Kobayashi, Mitsuyoshi; Morishita, Asahiro; Kobara, Hideki; Mori, Hirohito; Yoneyama, Hirohito; Deguchi, Akihiro; Himoto, Takashi; Kurokohchi, Kazutaka; Okano, Keiichi; Suzuki, Yasuyuki; Murao, Koji; Masaki, Tsutomu

    2013-12-30

    Metformin is a commonly used oral anti-hyperglycemic agent of the biguanide family. Recent studies suggest that metformin may reduce cancer risk and improve prognosis. However, the antitumor mechanism of metformin in several types of cancers, including hepatocellular carcinoma (HCC), has not been elucidated. The goal of the present study was to evaluate the effects of metformin on HCC cell proliferation in vitro and in vivo, and to study microRNAs (miRNAs) associated with the antitumor effect of metformin in vitro. We used the cell lines Alex, HLE and Huh7, and normal hepatocytes to study the effects of metformin on human HCC cells. In an in vivo study, athymic nude mice bearing xenograft tumors were treated with metformin or left untreated. Tumor growth was recorded after 4 weeks, and the expression of cell cycle‑related proteins was determined. Metformin inhibited the proliferation of Alex, HLE and Huh7 cells in vitro and in vivo. Metformin blocked the cell cycle in G0/G1 in vitro and in vivo. This blockade was accompanied by a strong decrease of G1 cyclins, especially cyclin D1, cyclin E and cyclin-dependent kinase 4 (Cdk4). In addition, microRNA (miRNA) expression was markedly altered by the treatment with metformin in vitro and in vivo. In addition, various miRNAs induced by metformin also may contribute to the suppression of tumor growth. Our results demonstrate that metformin inhibits the growth of HCC, possibly by inducing G1 cell cycle arrest through the alteration of microRNAs. PMID:24378856

  8. Tempol, a Membrane-Permeable Radical Scavenger, Exhibits Anti-Inflammatory and Cardioprotective Effects in the Cerulein-Induced Pancreatitis Rat Model

    PubMed Central

    Marciniak, Andrzej; Walczyna, Beata; Rajtar, Grażyna; Marciniak, Sebastian; Wojtak, Andrzej; Lasiecka, Katarzyna

    2016-01-01

    To date, it remains unclear whether mild form of acute pancreatitis (AP) may cause myocardial damage which may be asymptomatic for a long time. Pathogenesis of AP-related cardiac injury may be attributed in part to ROS/RNS overproduction. The aim of the present study was to evaluate the oxidative stress changes in both the pancreas and the heart and to estimate the protective effects of 1-oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine (tempol) at the early phase of AP. Cerulein-induced AP led to the development of acute edematous pancreatitis with a significant decrease in the level of sulfhydryl (–SH) groups (oxidation marker) both in heart and in pancreatic tissues as well as a substantial increase in plasma creatine kinase isoenzyme (CK-MB) activity (marker of the heart muscle lesion) which confirmed the role of oxidative stress in the pathogenesis of cardiac damage. The tempol treatment significantly reduced the intensity of inflammation and oxidative damage and decreased the morphological evidence of pancreas injury at early AP stages. Moreover, it markedly attenuated AP-induced cardiac damage revealed by normalization of the –SH group levels and CK-MB activity. On the basis of these studies, it is possible to conclude that tempol has a profound protective effect against cardiac and pancreatic damage induced by AP. PMID:26770650

  9. Effects of gliclazide add on metformin on serum omentin-1 levels in patients with type 2 diabetes mellitus

    PubMed Central

    Al-Gareeb, Ali I.; Alrubai, Haidar F.; Suliaman, Sammar M.

    2016-01-01

    Background: Omentin is a newly identified adipokine that has beneficial influence against cardiovascular disorders. Hence, considering the impact of anti-diabetic drug on omentin levels may provide an adjuvant strategy to protect diabetic patients against valuable clinical hazards. Aim of the Study: To investigate the influence of metformin alone or in combination with gliclazide on the level of serum omentin among patients with type 2 diabetes mellitus (T2DM). Patients and Methods: A total of 70 newly diagnosed patients with T2DM were enrolled in this randomized, double-blind prospective study, and divided into two equal groups based on treatment regimen in which Group 1 treated with metformin (1000 mg) and Group 2 treated with metformin (1000 mg) plus gliclazide (80 mg). Blood glucose levels, HbA1C, insulin levels, and serum omentin-1 were measured at baseline and after 12 weeks of treatment. Result: Use of gliclazide as an add-on therapy to metformin in patients with T2DM result in better glycemic control evidenced by significant reductions in the levels of blood glucose levels and HbA1C and much more improvement in insulin sensitivity evidenced by significant decreased in insulin resistance index, whereas it has adverse impact on serum omentin-1 levels evidenced by significant decrement in omentin-1 level in comparison to their pretreatment levels among Group 2 patients. Conclusions: Adding of gliclazide to metformin in treatment of patients with T2DM might extend the therapeutic action of metformin in regarding much better controlling of glycemic indices, but, at the same time, it might attenuate the cardioprotective effects of metformin by its adverse influence on serum omentin-1 levels. PMID:27042415

  10. Lack of effect of metformin on mammary carcinogenesis in nondiabetic rat and mouse models.

    PubMed

    Thompson, Matthew D; Grubbs, Clinton J; Bode, Ann M; Reid, Joel M; McGovern, Renee; Bernard, Philip S; Stijleman, Inge J; Green, Jeffrey E; Bennett, Christina; Juliana, M Margaret; Moeinpour, Fariba; Steele, Vernon E; Lubet, Ronald A

    2015-03-01

    Epidemiologic studies have shown that diabetics receiving the biguanide metformin, as compared with sulfonylureas or insulin, have a lower incidence of breast cancer. Metformin increases levels of activated AMPK (AMP-activated protein kinase) and decreases circulating IGF-1; encouraging its potential use in both cancer prevention and therapeutic settings. In anticipation of clinical trials in nondiabetic women, the efficacy of metformin in nondiabetic rat and mouse mammary cancer models was evaluated. Metformin was administered by gavage or in the diet, at a human equivalent dose, in standard mammary cancer models: (i) methylnitrosourea (MNU)-induced estrogen receptor-positive (ER(+)) mammary cancers in rats, and (ii) MMTV-Neu/p53KO ER(-) (estrogen receptor-negative) mammary cancers in mice. In the MNU rat model, metformin dosing (150 or 50 mg/kg BW/d, by gavage) was ineffective in decreasing mammary cancer multiplicity, latency, or weight. Pharmacokinetic studies of metformin (150 mg/kg BW/d, by gavage) yielded plasma levels (Cmax and AUC) higher than humans taking 1.5 g/d. In rats bearing small palpable mammary cancers, short-term metformin (150 mg/kg BW/d) treatment increased levels of phospho-AMPK and phospho-p53 (Ser20), but failed to reduce Ki67 labeling or expression of proliferation-related genes. In the mouse model, dietary metformin (1,500 mg/kg diet) did not alter final cancer incidence, multiplicity, or weight. Metformin did not prevent mammary carcinogenesis in two mammary cancer models, raising questions about metformin efficacy in breast cancer in nondiabetic populations. PMID:25681088

  11. Metformin and cancer: Between the bioenergetic disturbances and the antifolate activity.

    PubMed

    Jara, J A; López-Muñoz, R

    2015-11-01

    For decades, metformin has been the first-line drug for the treatment of type II diabetes mellitus, and it thus is the most widely prescribed antihyperglycemic drug. Retrospective studies associate the use of metformin with a reduction in cancer incidence and cancer-related death. However, despite extensive research about the molecular effects of metformin in cancer cells, its mode of action remains controversial. In this review, we summarize the current molecular evidence in an effort to elucidate metformin's mode of action against cancer cells. Some authors describe that metformin acts directly on mitochondria, inhibiting complex I and restricting the cell's ability to cope with energetic stress. Furthermore, as the drug interrupts the tricarboxylic acid cycle, metformin-induced alteration of mitochondrial function leads to a compensatory increase in lactate and glycolytic ATP. It has also been reported that cell cycle arrest, autophagy, apoptosis and cell death induction is mediated by the activation of AMPK and Redd1 proteins, thus inhibiting the mTOR pathway. Additionally, unbiased metabolomics studies have provided strong evidence to support that metformin alters the methionine and folate cycles, with a concomitant decrease in nucleotide synthesis. Indeed, purines such as thymidine or hypoxanthine restore the proliferation of tumor cells treated with metformin in vitro. Consequently, some authors prefer to refer to metformin as an "antimetabolite drug" rather than a "mitochondrial toxin". Finally, we also review the current controversy concerning the relationship between the experimental conditions of in vitro-reported effects and the plasma concentrations achieved by chronic treatment with metformin. PMID:26277279

  12. Metformin Restores Parkin-Mediated Mitophagy, Suppressed by Cytosolic p53.

    PubMed

    Song, Young Mi; Lee, Woo Kyung; Lee, Yong-Ho; Kang, Eun Seok; Cha, Bong-Soo; Lee, Byung-Wan

    2016-01-01

    Metformin is known to alleviate hepatosteatosis by inducing 5' adenosine monophosphate (AMP)-kinase-independent, sirtuin 1 (SIRT1)-mediated autophagy. Dysfunctional mitophagy in response to glucolipotoxicities might play an important role in hepatosteatosis. Here, we investigated the mechanism by which metformin induces mitophagy through restoration of the suppressed Parkin-mediated mitophagy. To this end, our ob/ob mice were divided into three groups: (1) ad libitum feeding of a standard chow diet; (2) intraperitoneal injections of metformin 300 mg/kg; and (3) 3 g/day caloric restriction (CR). HepG2 cells were treated with palmitate (PA) plus high glucose in the absence or presence of metformin. We detected enhanced mitophagy in ob/ob mice treated with metformin or CR, whereas mitochondrial spheroids were observed in mice fed ad libitum. Metabolically stressed ob/ob mice and PA-treated HepG2 cells showed an increase in expression of endoplasmic reticulum (ER) stress markers and cytosolic p53. Cytosolic p53 inhibited mitophagy by disturbing the mitochondrial translocation of Parkin, as demonstrated by immunoprecipitation. However, metformin decreased ER stress and p53 expression, resulting in induction of Parkin-mediated mitophagy. Furthermore, pifithrin-α, a specific inhibitor of p53, increased mitochondrial incorporation into autophagosomes. Taken together, these results indicate that metformin treatment facilitates Parkin-mediated mitophagy rather than mitochondrial spheroid formation by decreasing the inhibitory interaction with cytosolic p53 and increasing degradation of mitofusins. PMID:26784190

  13. Metformin Restores Parkin-Mediated Mitophagy, Suppressed by Cytosolic p53

    PubMed Central

    Song, Young Mi; Lee, Woo Kyung; Lee, Yong-ho; Kang, Eun Seok; Cha, Bong-Soo; Lee, Byung-Wan

    2016-01-01

    Metformin is known to alleviate hepatosteatosis by inducing 5’ adenosine monophosphate (AMP)-kinase-independent, sirtuin 1 (SIRT1)-mediated autophagy. Dysfunctional mitophagy in response to glucolipotoxicities might play an important role in hepatosteatosis. Here, we investigated the mechanism by which metformin induces mitophagy through restoration of the suppressed Parkin-mediated mitophagy. To this end, our ob/ob mice were divided into three groups: (1) ad libitum feeding of a standard chow diet; (2) intraperitoneal injections of metformin 300 mg/kg; and (3) 3 g/day caloric restriction (CR). HepG2 cells were treated with palmitate (PA) plus high glucose in the absence or presence of metformin. We detected enhanced mitophagy in ob/ob mice treated with metformin or CR, whereas mitochondrial spheroids were observed in mice fed ad libitum. Metabolically stressed ob/ob mice and PA-treated HepG2 cells showed an increase in expression of endoplasmic reticulum (ER) stress markers and cytosolic p53. Cytosolic p53 inhibited mitophagy by disturbing the mitochondrial translocation of Parkin, as demonstrated by immunoprecipitation. However, metformin decreased ER stress and p53 expression, resulting in induction of Parkin-mediated mitophagy. Furthermore, pifithrin-α, a specific inhibitor of p53, increased mitochondrial incorporation into autophagosomes. Taken together, these results indicate that metformin treatment facilitates Parkin-mediated mitophagy rather than mitochondrial spheroid formation by decreasing the inhibitory interaction with cytosolic p53 and increasing degradation of mitofusins. PMID:26784190

  14. Metformin is an AMP kinase-dependent growth inhibitor for breast cancer cells.

    PubMed

    Zakikhani, Mahvash; Dowling, Ryan; Fantus, I George; Sonenberg, Nahum; Pollak, Michael

    2006-11-01

    Recent population studies provide clues that the use of metformin may be associated with reduced incidence and improved prognosis of certain cancers. This drug is widely used in the treatment of type 2 diabetes, where it is often referred to as an "insulin sensitizer" because it not only lowers blood glucose but also reduces the hyperinsulinemia associated with insulin resistance. As insulin and insulin-like growth factors stimulate proliferation of many normal and transformed cell types, agents that facilitate signaling through these receptors would be expected to enhance proliferation. We show here that metformin acts as a growth inhibitor rather than an insulin sensitizer for epithelial cells. Breast cancer cells can be protected against metformin-induced growth inhibition by small interfering RNA against AMP kinase. This shows that AMP kinase pathway activation by metformin, recently shown to be necessary for metformin inhibition of gluconeogenesis in hepatocytes, is also involved in metformin-induced growth inhibition of epithelial cells. The growth inhibition was associated with decreased mammalian target of rapamycin and S6 kinase activation and a general decrease in mRNA translation. These results provide evidence for a mechanism that may contribute to the antineoplastic effects of metformin suggested by recent population studies and justify further work to explore potential roles for activators of AMP kinase in cancer prevention and treatment. PMID:17062558

  15. Metformin prevents cancer metastasis by inhibiting M2-like polarization of tumor associated macrophages

    PubMed Central

    Ding, Ling; Liang, Guikai; Yao, Zhangting; Zhang, Jieqiong; Liu, Ruiyang; Chen, Huihui; Zhou, Yulu; Wu, Honghai; Yang, Bo; He, Qiaojun

    2015-01-01

    Accumulated evidence suggests that M2-like polarized tumor associated macrophages (TAMs) plays an important role in cancer progression and metastasis, establishing TAMs, especially M2-like TAMs as an appealing target for therapy intervention. Here we found that metformin significantly suppressed IL-13 induced M2-like polarization of macrophages, as illustrated by reduced expression of CD206, down-regulation of M2 marker mRNAs, and inhibition of M2-like macrophages promoted migration of cancer cells and endothelial cells. Metformin triggered AMPKα1 activation in macrophage and silencing of AMPKα1 partially abrogated the inhibitory effect of metformin in IL-13 induced M2-like polarization. Administration of AICAR, another activator of AMPK, also blocked the M2-like polarization of macrophages. Metformin greatly reduced the number of metastases of Lewis lung cancer without affecting tumor growth. In tumor tissues, the percentage of M2-like macrophage was decreased and the area of pericyte-coated vessels was increased. Further, the anti-metastatic effect of metformin was abolished when the animals were treated with macrophages eliminating agent clodronate liposome. These findings suggest that metformin is able to block the M2-like polarization of macrophages partially through AMPKα1, which plays an important role in metformin inhibited metastasis of Lewis lung cancer. PMID:26497364

  16. Metformin is a potent inhibitor of endometrial cancer cell proliferation – implications for a novel treatment strategy1

    PubMed Central

    Cantrell, Leigh A.; Zhou, Chunxiao; Mendivil, Alberto; Malloy, Kimberly M.; Gehrig, Paola A.; Bae-Jump, Victoria L.

    2009-01-01

    Objectives Obesity and diabetes are strong risk factors that drive the development of type I endometrial cancers. Recent epidemiological evidence suggests that metformin may lower cancer risk and reduce rates of cancer deaths among diabetic patients. In order to better understand metformin's anti-tumorigenic potential, our goal was to assess the effect of metformin on proliferation and expression of key targets of metformin cell signaling in endometrial cancer cell lines. Methods The endometrial cancer cell lines, ECC-1 and Ishikawa, were used. Cell proliferation was assessed after exposure to metformin. Cell cycle progression was evaluated by flow cytometry. Apoptosis was assessed by ELISA for caspase-3 activity. hTERT expression was determined by real-time RT-PCR. Western immunoblotting was performed to determine the expression of the downstream targets of metformin. Results Metformin potently inhibited growth in a dose-dependent manner in both cell lines (IC50 of 1 mM). Treatment with metformin resulted in G1 arrest, induction of apoptosis and decreased hTERT expression. Western immunoblot analysis demonstrated that metformin induced phosphorylation of AMPK, its immediate downstream mediator, within 24 hours of exposure. In parallel, treatment with metformin decreased phosphorylation of S6 protein, a key target of the mTOR pathway. Conclusions We find that metformin is a potent inhibitor of cell proliferation in endometrial cancer cell lines. This effect is partially mediated through AMPK activation and subsequent inhibition of the mTOR pathway. This work should provide the scientific foundation for future investigation of metformin as a strategy for endometrial cancer prevention and treatment. PMID:19822355

  17. Buccal delivery of metformin: TR146 cell culture model evaluating the use of bioadhesive chitosan discs for drug permeability enhancement.

    PubMed

    Sander, Camilla; Nielsen, Hanne Mørck; Jacobsen, Jette

    2013-12-31

    The oral cavity is considered an attractive site of drug administration. Metformin is currently, used in oral diabetes treatment. The aim of the current study was to study the feasibility of metformin, to permeate the buccal epithelium applying a bioadhesive and permeation enhancing drug delivery system. The in vitro TR146 cell culture model was used to study the effect of drug concentration (5-100mM) and the impact of a bioadhesive chitosan formulation (discs) and chitosan in solution (0-20mg/mL) acting as a permeation enhancer. The permeation of metformin occurred by passive diffusion via the paracellular pathway driven by the concentration gradient, yet with a possibility of increasing the metformin transport by using higher, donor concentrations. When using floating baskets, as a new application of the TR146 cell culture model, it was possible to observe a time-dependent effect of the bioadhesive metformin discs and, metformin permeation may be increased due to a combination of bioadhesion and permeation enhancement induced by chitosan, although the permeation enhancing effect of chitosan was not statistically significant. The limited apparent buccal permeability of metformin observed in vitro, suggest that in vivo absorption of therapeutic doses of metformin needs to take place as a combination of buccal and intestinal absorption as metformin therapy requires the use of high doses. PMID:24148665

  18. Gene transfer as a strategy to achieve permanent cardioprotection I: rAAV-mediated gene therapy with inducible nitric oxide synthase limits infarct size 1 year later without adverse functional consequences

    PubMed Central

    Li, Qianhong; Guo, Yiru; Wu, Wen-Jian; Ou, Qinghui; Zhu, Xiaoping; Tan, Wei; Yuan, Fangping; Chen, Ning; Dawn, Buddhadeb; Luo, Li; O’Brien, Erin

    2013-01-01

    The ultimate goal of prophylactic gene therapy is to confer permanent protection against ischemia. Although gene therapy with inducible nitric oxide synthase (iNOS) is known to protect against myocardial infarction at 3 days and up to 2 months, the long-term effects on myocardial ischemic injury and function are unknown. To address this issue, we created a recombinant adeno-associated viral vector carrying the iNOS gene (rAAV/iNOS), which enables long-lasting transgene expression. The ability of rAAV/iNOS to direct the expression of functional iNOS protein was confirmed in COS-7 cells before in vivo gene transfer. Mice received injections in the anterior LV wall of rAAV/LacZ or rAAV/iNOS; 1 year later, they underwent a 30-min coronary occlusion (O) and 4 h of reperfusion (R). iNOS gene transfer resulted in elevated iNOS protein expression (+3-fold vs. the LacZ group, n = 6; P < 0.05) and iNOS activity (+4.4-fold vs. the LacZ group, n = 6; P < 0.05) 1 year later. Infarct size (% of risk region) was dramatically reduced at 1 year after iNOS gene transfer (13.5 ± 2.2%, n = 12, vs. 41.7 ± 2.9%, n = 10, in the LacZ group; P < 0.05). The infarct-sparing effect of iNOS gene therapy at 1 year was as powerful as that observed 24 h after ischemic preconditioning (six 4-min O/4-min R cycles) (19.3 ± 2.3%, n = 11; P < 0.05). Importantly, compared with the LacZ group (n = 11), iNOS gene transfer (n = 10) had no effect on LV dimensions or function for up to 1 year (at 1 year: FS 34.5 ± 2.0 vs. 34.6 ± 2.6%, EF 57.0 ± 2.0 vs. 59.7 ± 2.9%, LVEDD 4.3 ± 0.1 vs. 4.2 ± 0.2 mm, LVESD 2.8 ± 0.1 vs. 2.9 ± 0.2 mm) (echocardiography). These data demonstrate, for the first time, that rAAV-mediated iNOS gene transfer affords long-term, probably permanent (1 year), cardioprotection without adverse functional consequences, providing a strong rationale for further preclinical testing of prophylactic gene therapy. PMID:21779912

  19. Cardioprotective effects of rutin via alteration in TNF-α, CRP, and BNP levels coupled with antioxidant effect in STZ-induced diabetic rats.

    PubMed

    Saklani, Ravi; Gupta, Suresh Kumar; Mohanty, Ipseeta Ray; Kumar, Binit; Srivastava, Sushma; Mathur, Rajani

    2016-09-01

    Diabetic cardiomyopathy (DCM) is a dreadful complication of diabetes responsible for 80 % mortality in diabetic patients, but unfortunately its pharmacotherapy is still incomplete. Rutin is a naturally occurring flavonoid having a long history of use in nutritional supplements for its action against oxidative stress, inflammation, and hyperglycemia, the key players involved in the progression of DCM, but remains unexplored for its role in DCM. This study was conducted to address this lacuna. It was performed in 4-week-old Streptozotocin-induced (45 mg/kg) diabetic rats for a period of 24 weeks to mimic the cardiotoxic effect of chronic hyperglycemia in diabetic patient's heart and to investigate the effect of rutin (50 mg/kg/day) in ameliorating these effects. Heart of the diabetic rats showed altered ECG parameters, reduced total antioxidant capacity, increased inflammatory assault, and degenerative changes. Interestingly, rutin treatment significantly ameliorated these changes with decrease in blood glucose level (p > 0.001), % HbA1c (p > 0.001) and reduced expression of TNF-α (p < 0.001), CRP (p < 0.001), and BNP (p < 0.01) compared to diabetic control rats. In addition, rutin provided significant protection against diabetes associated oxidative stress (p < 0.05), prevented degenerative changes in heart, and improved ECG parameters compared to diabetic control rats. The heart-to-body weight ratio was significantly reduced in rutin treatment group compared to diabetic control rats (p < 0.001). In conclusion, this study implicates that oxidative stress and inflammation are the central players involved in the progression of DCM and rutin ameliorates DCM through its antioxidant and anti-inflammatory actions on heart. PMID:27443845

  20. Statin-Induced Cardioprotection Against Ischemia-Reperfusion Injury: Potential Drug-Drug Interactions. Lesson to be Learnt by Translating Results from Animal Models to the Clinical Settings.

    PubMed

    Birnbaum, Gilad D; Birnbaum, Itamar; Ye, Yumei; Birnbaum, Yochai

    2015-10-01

    Numerous interventions have been shown to limit myocardial infarct size in animal models; however, most of these interventions have failed to have a significant effect in clinical trials. One potential explanation for the lack of efficacy in the clinical setting is that in bench models, a single intervention is studied without the background of other interventions or modalities. This is in contrast to the clinical setting in which new medications are added to the "standard of care" treatment that by now includes a growing number of medications. Drug-drug interaction may lead to alteration, dampening, augmenting or masking the effects of the intended intervention. We use the well described model of statin-induced myocardial protection to demonstrate potential interactions with agents which are commonly concomitantly used in patients with stable coronary artery disease and/or acute coronary syndromes. These interactions could potentially explain the reduced efficacy of statins in the clinical trials compared to the animal models. In particular, caffeine and aspirin could attenuate the infarct size limiting effects of statins; morphine could delay the onset of protection or mask the protective effect in patients with ST elevation myocardial infarction, whereas other anti-platelet agents (dipyridamole, cilostazol and ticagrelor) may augment (or mask) the effect due to their favorable effects on adenosine cell reuptake and intracellular cAMP levels. We recommend that after characterizing the effects of new modalities in single intervention bench research, studies should be repeated in the background of standard-of-care medications to assure that the magnitude of the effect is not altered before proceeding with clinical trials. PMID:26303765

  1. Preconditioning at a distance: Involvement of endothelial vasoactive substances in cardioprotection against ischemia-reperfusion injury.

    PubMed

    Aggarwal, Sapna; Randhawa, Puneet Kaur; Singh, Nirmal; Jaggi, Amteshwar Singh

    2016-04-15

    There is growing preclinical as well as clinical evidence supporting remote ischemic preconditioning (RIPC), in which short cycles of non-fatal ischemia followed by reperfusion to an organ or tissue distant from the heart elicits cardioprotection. It is the most practical, non-invasive, cost-free, and clinically compatible, secure procedure for reducing ischemia-reperfusion induced injury. The use of a conventional blood pressure cuff on the upper or lower limb in eliciting cardioprotection has expedited its clinical applicability. Endothelium has been documented to respond very quickly to blood flow and hypoxia by releasing different humoral factors such as endothelium derived releasing factor, endothelium derived contracting factor, endothelium derived hyperpolarizing factor. In recent years, there have been studies suggesting the key role of endothelial derived factors in RIPC induced cardioprotection. The signaling cascade involves nitric oxide, gap junctions, epoxyeicosatrienoic (EETs) acids, Ca-activated K(+) channels, angiotensin II, thromboxane A2, superoxide anions and prostacyclin. The present review describes the role of these endothelial derived factors in RIPC induced cardioprotection with possible mechanisms. PMID:26979771

  2. Cardioprotective Potentials of Plant-Derived Small Molecules against Doxorubicin Associated Cardiotoxicity

    PubMed Central

    Ojha, Shreesh; Al Taee, Hasan; Goyal, Sameer; Mahajan, Umesh B.; Patil, Chandrgouda R.; Arya, D. S.; Rajesh, Mohanraj

    2016-01-01

    Doxorubicin (DOX) is a potent and widely used anthracycline antibiotic for the treatment of several malignancies. Unfortunately, the clinical utility of DOX is often restricted due to the elicitation of organ toxicity. Particularly, the increased risk for the development of dilated cardiomyopathy by DOX among the cancer survivors warrants major attention from the physicians as well as researchers to develop adjuvant agents to neutralize the noxious effects of DOX on the healthy myocardium. Despite these pitfalls, the use of traditional cytotoxic drugs continues to be the mainstay treatment for several types of cancer. Recently, phytochemicals have gained attention for their anticancer, chemopreventive, and cardioprotective activities. The ideal cardioprotective agents should not compromise the clinical efficacy of DOX and should be devoid of cumulative or irreversible toxicity on the naïve tissues. Furthermore, adjuvants possessing synergistic anticancer activity and quelling of chemoresistance would significantly enhance the clinical utility in combating DOX-induced cardiotoxicity. The present review renders an overview of cardioprotective effects of plant-derived small molecules and their purported mechanisms against DOX-induced cardiotoxicity. Phytochemicals serve as the reservoirs of pharmacophore which can be utilized as templates for developing safe and potential novel cardioprotective agents in combating DOX-induced cardiotoxicity. PMID:27313831

  3. Probable hepatotoxicity associated with the use of metformin in type 2 diabetes

    PubMed Central

    Hashmi, Taqi

    2011-01-01

    This is a case report of a 44-year-old obese female who developed subclinical hepatic injury 4 weeks after starting metformin for type 2 diabetes. She had a rise in her alanine aminotransferase which peaked at 5 months (738 U/l) and rapidly declined within days of discontinuing her metformin. No other positive evidence of alternative causes for the hepatic injury was found. The likelihood of metformin-induced injury was 7 on the Naranjo scale of adverse drug reactions. A brief review of the 11 previously reported cases in the English medical literature is also made. PMID:22679227

  4. Metformin inhibits 7,12-dimethylbenz[a]anthracene-induced breast carcinogenesis and adduct formation in human breast cells by inhibiting the cytochrome P4501A1/aryl hydrocarbon receptor signaling pathway

    SciTech Connect

    Maayah, Zaid H.; Ghebeh, Hazem; Alhaider, Abdulqader A.; El-Kadi, Ayman O.S.; Soshilov, Anatoly A.; Denison, Michael S.; Ansari, Mushtaq Ahmad; Korashy, Hesham M.

    2015-04-15

    Recent studies have established that metformin (MET), an oral anti-diabetic drug, possesses antioxidant activity and is effective against different types of cancer in several carcinogen-induced animal models and cell lines. However, whether MET can protect against breast cancer has not been reported before. Therefore, the overall objectives of the present study are to elucidate the potential chemopreventive effect of MET in non-cancerous human breast MCF10A cells and explore the underlying mechanism involved, specifically the role of cytochrome P4501A1 (CYP1A1)/aryl hydrocarbon receptor (AhR) pathway. Transformation of the MCF10A cells into initiated breast cancer cells with DNA adduct formation was conducted using 7,12-dimethylbenz[a]anthracene (DMBA), an AhR ligand. The chemopreventive effect of MET against DMBA-induced breast carcinogenesis was evidenced by the capability of MET to restore the induction of the mRNA levels of basic excision repair genes, 8-oxoguanine DNA glycosylase (OGG1) and apurinic/apyrimidinic endonuclease1 (APE1), and the level of 8-hydroxy-2-deoxyguanosine (8-OHdG). Interestingly, the inhibition of DMBA-induced DNA adduct formation was associated with proportional decrease in CYP1A1 and in NAD(P)H:quinone oxidoreductase 1 (NQO1) gene expression. Mechanistically, the involvements of AhR and nuclear factor erythroid 2-related factor-2 (Nrf2) in the MET-mediated inhibition of DMBA-induced CYP1A1 and NQO1 gene expression were evidenced by the ability of MET to inhibit DMBA-induced xenobiotic responsive element and antioxidant responsive element luciferase reporter gene expression which suggests an AhR- and Nrf2-dependent transcriptional control. However, the inability of MET to bind to AhR suggests that MET is not an AhR ligand. In conclusion, the present work shows a strong evidence that MET inhibits the DMBA-mediated carcinogenicity and adduct formation by inhibiting the expression of CYP1A1 through an AhR ligand-independent mechanism

  5. Metformin exerts anticancer effects through the inhibition of the Sonic hedgehog signaling pathway in breast cancer.

    PubMed

    Fan, Cong; Wang, Yunshan; Liu, Ziming; Sun, Ying; Wang, Xiuwen; Wei, Guangwei; Wei, Junmin

    2015-07-01

    Metformin, a widely prescribed antidiabetic drug, has previously been shown to lower the risk of certain types of cancer, including that of breast cancer, and to improve prognosis. Its anticancer effects, which are mediated by the activation of AMP-activated protein kinase (AMPK), have become notable. The Sonic hedgehog (Shh) signaling pathway is involved in changes in mammary ducts and malignant transformation. The aim of the present study was to elucidate the role of the Shh pathway in mediating the anticancer effects of metformin and the correlation between AMPK and the Shh pathway. We investigated the effectiveness of metformin in inhibiting the proliferation, migration, invasion and stemness of breast cancer cells in vitro using RNA extraction and reverse transcription‑polymerase chain reaction (RT-PCR), western blot analysis, cell proliferation assay, scratch-wound assay (cell migration assay), cell invasion assay, mammosphere culture and flow cytometry. In in vivo experiments, a tumor xenograft model was used to detect the effects of metformin on cancer cell proliferation. The results revealed that the treatment of breast cancer cells with metformin led to the inhibition of the Shh signaling pathway. Importantly, metformin inhibited recombinant human Shh (rhShh)‑induced cell migration, invasion, and stemness, and impaired cell proliferation both in vitro and in vivo. Furthermore, the small interfering RNA (siRNA)‑mediated downregulation of AMPK reversed the inhibitory effects of metformin on rhShh‑induced Gli-1 expression and stemness. Our findings identified a role of the Shh signaling pathway in the anticancer effects of metformin in breast cancer. Furthermore, we revealed that the metformin-mediated inhibition of the Shh signaling pathway may be dependent on AMPK. PMID:25999130

  6. Metformin Disrupts Crosstalk Between G protein-Coupled Receptor and Insulin Receptor Signaling Systems and Inhibits Pancreatic Cancer Growth

    PubMed Central

    Kisfalvi, Krisztina; Eibl, Guido; Sinnett-Smith, James; Rozengurt, Enrique

    2009-01-01

    Recently we identified a novel crosstalk between insulin and G-protein-coupled receptor (GPCR) signaling pathways in human pancreatic cancer cells. Insulin enhanced GPCR signaling through a rapamycin-sensitive mTOR-dependent pathway. Metformin, the most widely used drug in the treatment of type-2 diabetes, activates AMP kinase (AMPK), which negatively regulates mTOR. Here, we determined whether metformin disrupts crosstalk between insulin receptor and GPCR signaling in pancreatic cancer cells. Treatment of human pancreatic cancer cells (PANC-1, MIAPaCa-2, BxPC-3) with insulin (10ng/ml) for 5 min markedly enhanced the increase in intracellular [Ca2+] induced by GPCR agonists (e.g. neurotensin, bradykinin, angiotensin II). Metformin pretreatment completely abrogated insulin-induced potentiation of Ca2+ signaling but did not interfere with the effect of GPCR agonists alone. Insulin also enhanced GPCR agonist-induced growth, measured by DNA synthesis, and numbers of cells cultured in adherent or non-adherent conditions. Low doses of metformin (0.1-0.5 mM) blocked stimulation of DNA synthesis, anchorage-dependent and independent growth induced by insulin and GPCR agonists. Treatment with metformin induced striking and sustained increase in the phosphorylation of AMPK at Thr172 and a selective AMPK inhibitor (compound C, at 5μM) reversed the effects of metformin on [Ca2+]i, and DNA synthesis, indicating that metformin acts through AMPK activation. In view of these results we tested whether metformin inhibits pancreatic cancer growth. Administration of metformin significantly decreased the growth of MIAPaCa-2 and PANC-1 cells xenografted on the flank of nude mice. The results raise the possibility that metformin could be a potential candidate in novel treatment strategies for human pancreatic cancer. PMID:19679549

  7. Metformin decreases IL-22 secretion to suppress tumor growth in an orthotopic mouse model of hepatocellular carcinoma.

    PubMed

    Zhao, Dong; Long, Xi-Dai; Lu, Tian-Fei; Wang, Tao; Zhang, Wei-Wei; Liu, Yi-Xiao; Cui, Xiao-Lan; Dai, Hui-Juan; Xue, Feng; Xia, Qiang

    2015-06-01

    Epidemiological, preclinical and cellular studies in the last 5 years have shown that metformin exerts anti-tumoral properties, but its mode of action in cancer remains unclear. Here, we investigated the effects of metformin on a mouse hepatocellular carcinoma (HCC) model and tumor-associated T cell immune responses. Oral metformin administration led to a significant reduction of tumor growth, which was accompanied by decreased interleukin-22 (IL-22). Meanwhile, IL-22-induced STAT3 phosphorylation and upregulation of downstream genes Bcl-2 and cyclin D1 were inhibited by metformin. At the cellular level, metformin attenuated Th1- and Th17-derived IL-22 production. Furthermore, metformin inhibited de novo generation of Th1 and Th17 cells from naive CD4(+) cells. These observations were further supported by the fact that metformin treatment inhibited CD3/CD28-induced IFN-γ and IL-17A expression along with the transcription factors that drive their expression (T-bet [Th1] and ROR-γt [Th17], respectively). The effects of metformin on T cell differentiation were mediated by downregulated STAT3 and STAT4 phosphorylation via the AMP-activated kinase-mammalian target of rapamycin complex 1 pathway. Notably, metformin led to a reduction in glucose transporter Glut1 expression, resulting in less glucose uptake, which is critical to regulate CD4(+) T cell fate. Taken together, these findings provide evidence for the growth-inhibitory and immune-modulatory effects of metformin in HCC and thus, broaden our understanding about the action of metformin in liver cancer treatment. PMID:25370454

  8. Is it time to test biguanide metformin in the treatment of melanoma?

    PubMed

    Cerezo, Michael; Tomic, Tijana; Ballotti, Robert; Rocchi, Stéphane

    2015-01-01

    Metformin is the most widely used antidiabetic drug that belongs to the biguanide class. It is very well tolerated and has the major clinical advantage of not inducing hypoglycemia. Metformin decreases hepatic glucose production via a mechanism requiring liver kinase B1, which controls the metabolic checkpoint, AMP-activated protein kinase-mammalian target of rapamycin and neoglucogenic genes. The effects of metformin on this pathway results in reduced protein synthesis and cell proliferation. These observations have given the impetus for many investigations on the role of metformin in the regulation of tumor cell proliferation, cell-cycle regulation, apoptosis, and autophagy. Encouraging results from these studies have shown that metformin could potentially be used as an efficient anticancer drug in various neoplasms such as prostate, breast, lung, pancreas cancers, and melanoma. These findings are strengthened by retrospective epidemiological studies that have found a decrease in cancer risk in diabetic patients treated with metformin. In this review, we have focused our discussion on recent molecular mechanisms of metformin that have been described in various solid tumors in general and in melanoma in particular. PMID:24862830

  9. Effects of exercise and metformin on the prevention of glucose intolerance: a comparative study

    PubMed Central

    Molena-Fernandes, C.; Bersani-Amado, C. A.; Ferraro, Z. M.; Hintze, L. J.; Nardo, N.; Cuman, R. K. N.

    2015-01-01

    We aimed to evaluate the effects of aerobic exercise training (4 days) and metformin exposure on acute glucose intolerance after dexamethasone treatment in rats. Forty-two adult male Wistar rats (8 weeks old) were divided randomly into four groups: sedentary control (SCT), sedentary dexamethasone-treated (SDX), training dexamethasone-treated (DPE), and dexamethasone and metformin treated group (DMT). Glucose tolerance tests and in situ liver perfusion were undertaken on fasting rats to obtain glucose profiles. The DPE group displayed a significant decrease in glucose values compared with the SDX group. Average glucose levels in the DPE group did not differ from those of the DMT group, so we suggest that exercise training corrects dexamethasone-induced glucose intolerance and improves glucose profiles in a similar manner to that observed with metformin. These data suggest that exercise may prevent the development of glucose intolerance induced by dexamethasone in rats to a similar magnitude to that observed after metformin treatment. PMID:26421869

  10. Effects of exercise and metformin on the prevention of glucose intolerance: a comparative study.

    PubMed

    Molena-Fernandes, C; Bersani-Amado, C A; Ferraro, Z M; Hintze, L J; Nardo, N; Cuman, R K N

    2015-12-01

    We aimed to evaluate the effects of aerobic exercise training (4 days) and metformin exposure on acute glucose intolerance after dexamethasone treatment in rats. Forty-two adult male Wistar rats (8 weeks old) were divided randomly into four groups: sedentary control (SCT), sedentary dexamethasone-treated (SDX), training dexamethasone-treated (DPE), and dexamethasone and metformin treated group (DMT). Glucose tolerance tests and in situ liver perfusion were undertaken on fasting rats to obtain glucose profiles. The DPE group displayed a significant decrease in glucose values compared with the SDX group. Average glucose levels in the DPE group did not differ from those of the DMT group, so we suggest that exercise training corrects dexamethasone-induced glucose intolerance and improves glucose profiles in a similar manner to that observed with metformin. These data suggest that exercise may prevent the development of glucose intolerance induced by dexamethasone in rats to a similar magnitude to that observed after metformin treatment. PMID:26421869

  11. Electrical stimulation to optimize cardioprotective exosomes from cardiac stem cells.

    PubMed

    Campbell, C R; Berman, A E; Weintraub, N L; Tang, Y L

    2016-03-01

    Injured or ischemic cardiac tissue has limited intrinsic capacity for regeneration. While stem cell transplantation is a promising approach to stimulating cardiac repair, its success in humans has thus far been limited. Harnessing the therapeutic benefits of stem cells requires a better understanding of their mechanisms of action and methods to optimize their function. Cardiac stem cells (CSC) represent a particularly effective cellular source for cardiac repair, and pre-conditioning CSC with electrical stimulation (EleS) was demonstrated to further enhance their function, although the mechanisms are unknown. Recent studies suggest that transplanted stem cells primarily exert their effects through communicating with endogenous tissues via the release of exosomes containing cardioprotective molecules such as miRNAs, which upon uptake by recipient cells may stimulate survival, proliferation, and angiogenesis. Exosomes are also effective therapeutic agents in isolation and may provide a feasible alternative to stem cell transplantation. We hypothesize that EleS enhances CSC-mediated cardiac repair through its beneficial effects on production of cardioprotective exosomes. Moreover, we hypothesize that the beneficial effects of biventricular pacing in patients with heart failure may in part result from EleS-induced preconditioning of endogenous CSC to promote cardiac repair. With future research, our hypothesis may provide applications to optimize stem cell therapy and augment current pacing protocols, which may significantly advance the treatment of patients with heart disease. PMID:26880625

  12. SOCS3: A novel therapeutic target for cardioprotection.

    PubMed

    Yasukawa, Hideo; Nagata, Takanobu; Oba, Toyoharu; Imaizumi, Tsutomu

    2012-10-01

    The suppressors of cytokine signaling (SOCS) family of proteins are cytokine-inducible inhibitors of Janus kinase (JAK)-signal transducer and activator of the transcription (STAT) signaling pathways. Among the family, SOCS1 and SOCS3 potently suppress cytokine actions by inhibiting JAK kinase activities. The generation of mice lacking individual SOCS genes has been instrumental in defining the role of individual SOCS proteins in specific cytokine pathways in vivo; SOCS1 is an essential negative regulator of interferon-γ (IFNγ) and SOCS3 is an essential negative regulator of leukemia inhibitory factor (LIF). JAK-STAT3 activating cytokines have exhibited cardioprotective roles in the heart. The cardiac-specific deletion of SOCS3 enhances the activation of cardioprotective signaling pathways, inhibits myocardial apoptosis and fibrosis and results in the inhibition of left ventricular remodeling after myocardial infarction (MI). We propose that myocardial SOCS3 is a key determinant of left ventricular remodeling after MI, and SOCS3 may serve as a novel therapeutic target to prevent left ventricular remodeling after MI. In this review, we discuss the signaling pathways mediated by JAK-STAT and SOCS proteins and their roles in the development of myocardial injury under stress (e.g., pressure overload, viral infection and ischemia). PMID:24058778

  13. Antioxidative and Cardioprotective Properties of Anthocyanins from Defatted Dabai Extracts

    PubMed Central

    Khoo, Hock Eng; Azlan, Azrina; Nurulhuda, M. Halid; Ismail, Amin; Abas, Faridah; Hamid, Muhajir; Roowi, Suri

    2013-01-01

    This study aimed to determine anthocyanins and their antioxidative and cardioprotective properties in defatted dabai parts. Anthocyanins in crude extracts and extract fractions of defatted dabai peel and pericarp were quantified using UHPLC, while their antioxidant capacity and oxidative stress inhibition ability were evaluated by using DPPH and CUPRAC assays as well as linoleic acid oxidation system, hemoglobin oxidation, and PARP-1 inhibition ELISA. Cardioprotective effect of the defatted dabai peel extract was evaluated using hypercholesterolemic-induced New Zealand white rabbits. Six anthocyanins were detected in the defatted dabai peel, with the highest antioxidant capacities and oxidative stress inhibition effect compared to the other part. The defatted dabai peel extract has also inhibited lipid peroxidation (plasma MDA) and elevated cellular antioxidant enzymes (SOD and GPx) in the tested animal model. Major anthocyanin (cyanidin-3-glucoside) and other anthocyanins (pelargonidin-3-glucoside, malvidin-3-glucoside, cyanidin-3-galactoside, cyanidin-3-arabinoside, and peonidin-3-glucoside) detected in the defatted dabai peel are potential future nutraceuticals with promising medicinal properties. PMID:24368926

  14. [Lily polysaccharide 1 enhances the effect of metformin on proliferation and apoptosis of human breast carcinoma cells].

    PubMed

    Hou, Jin; Li, Fen; Li, Xinhua; Mei, Qibing; Mi, Man

    2016-06-01

    Objective To investigate the effect of metformin, alone or in combination with Lily polysaccharide 1 (LP1), on cell viability and apoptosis in MCF-7 human breast cancer cells. Methods LP1 (0.5, 1.0 mg/mL) and metformin (5, 10, 20, 50 mmol/L) were added into MCF-7 cell culture medium, followed by incubating for 72 hours in carbon dioxide incubators at 37DegreesCelsius. MCF-7 cell proliferation was determined using MTT assay; the apoptosis and cell cycle of MCF-7 cells were examined using annexin V-FITC/PI double staining combined with flow cytometry; Western blotting was used to determine the content of Bcl-2, Bax, adenosine monophosphate-activated protein kinase (AMPK) and phosphorated AMPK (p-AMPK) proteins. Results Metformin-induced inhibition of MCF-7 cell proliferation was significantly enhanced when 1 mg/mL LP1 was added in. Compared with the control group and the metformin only group, more cells were arrested to G1 and the apoptosis rate was raised obviously in the metformin and LP1 combination group. LP1 promoted the downregulated expression of Bcl-2 and the upregulated expression of Bax induced by metformin, but it didn't show any impact on the metformin-activated AMPK pathway. Conclusion LP1 enhances the proliferation-inhibitory and apoptosis-promoting effect of metformin on human breast carcinoma cells. The mechanism may be related with Bcl-2 downregulation and Bax upregulation. PMID:27371846

  15. Metformin use and young age lung cancer: A case series report

    PubMed Central

    DENG, BO; WANG, YI; XIE, DONG; STODDARD, SHAWN M.; YANG, PING

    2016-01-01

    Metformin, a widely-prescribed antihyperglycemic drug for the treatment of diabetes mellitus type 2 (DM-II), has been demonstrated to be antineoplastic in vivo and in vitro. However, various preclinical and epidemiological studies investigating the effects of metformin on lung cancer have obtained inconclusive results. The aim of the present study was to retrospectively investigate the effects of metformin, for the treatment of diabetes mellitus type 2 (DM-II), on the onset of lung cancer. In the present study, the pathological features of ten consecutive young age lung cancer cases, aged between 15 and 45 years old at the time of diagnosis and exhibiting existing primary DM, were investigated using the Mayo Clinic Lung Cancer Cohort database. Amongst this cohort, there were 2 cases of DM type 1 (DM-I) and 8 cases of DM-II. Of these patients, two exhibiting adenocarcinoma and DM-II had not been administered metformin; however, 1 patient exhibiting lymphoma and 4 patients with pulmonary neuroendocrine tumors (NETs) had been administered metformin at least 12 months prior to lung cancer diagnosis. The remaining 3 patients exhibiting NETs and DM-II had been treated with insulin therapy. The present study hypothesized that the high proportion of NETs observed in the cases of metformin-treated DM-II was unlikely to be a random event. It was suggested that metformin treatment was not effective in the prevention of pulmonary NETs, and that metformin may instead induce the occurrence of NETs via as yet unknown signaling pathways. The present hypothesis may potentially serve as a novel indicator for the requirement to monitor young patients with diabetes, who are being treated with metformin, for the occurrence of pulmonary NETs. PMID:27073573

  16. The Induction of Metformin Inhibitory Effects on Tumor Cell Growth in Hypoxic Condition.

    PubMed

    Safari, Zohreh; Safaralizadeh, Reza; Seyedzadeh, Mir Hadi; Valinezad Orang, Ayla; Zare, Ahad; Hosseinpour Feizi, Mohammad Ali; Kardar, Gholam Ali

    2015-12-01

    It is aimed to evaluate the actual anti-cancerous effects of metformin on cancer cells in hypoxic condition. Non-cancerous cells (HEK293) and cancer cells (MCF-7) were cultured in both hypoxia and normoxia conditions and treated with different concentrations of metformin. The proliferation, apoptosis, and necrosis rate were assessed using MTT test and Annexin V assay. The S6K1 phosphorylation was assessed using western blotting. Zymography was used to measure the activity of metalloproteinase-9 (MMP-9). Metformin treatment inhibited proliferation of cancer cells in the optimal concentration of 10 mM under hypoxia condition, while it showed no effects on non-cancerous cell viability. The statistical analysis of MTT assay indicated that the pro-apoptotic function of metformin for cancer cells under hypoxia condition compared to normoxia was significant with different metformin concentrations (p<0.01). However, the effect of metformin treatments for non-cancerous cells under hypoxia condition compared to normoxia was not significant. Western-blot analysis indicated a significant decrease in S6K1 phosphorylation in cancer cells under hypoxia condition (p<0.05). Nevertheless, there was no considerable difference between normoxia and hypoxia conditions in non-cancerous cells. MMP-9 zymography analysis revealed that the highest inhibition of MMP-9 activity was observed in hypoxia condition by 20mM of metformin concentration only in cancer cell. The results indicate that in hypoxia condition metformin exerts its anti-cancerous function by inhibiting proliferation and tumor progression and inducing cell apoptosis more effectively than normoxia condition. In line with cancer cell conditions, most importantly hypoxic condition, metformin can be considered as a potential anti-cancerous drug. PMID:26725558

  17. Antiproliferative and metabolic effects of metformin in a preoperative window clinical trial for endometrial cancer

    PubMed Central

    Schuler, Kevin M; Rambally, Brooke S; DiFurio, Megan J; Sampey, Brante P; Gehrig, Paola A; Makowski, Liza; Bae-Jump, Victoria L

    2015-01-01

    We conducted a preoperative window study of metformin in endometrial cancer (EC) patients and evaluated its antiproliferative, molecular and metabolic effects. Twenty obese women with endometrioid EC were treated with metformin (850 mg) daily for up to 4 weeks prior to surgical staging. Expression of the proliferation marker Ki-67, estrogen receptor (ER), progesterone receptor (PR), adenosine monophosphate-activated protein kinase (AMPK), and downstream targets of the mammalian target of rapamycin (mTOR) pathway were measured by immunohistochemistry. Global, untargeted metabolomics analysis of serum pre- and postmetformin treatment, and matched tumor, was performed. Metformin reduced proliferation by 11.75% (P = 0.008) based on the comparison of pre- and posttreatment endometrial tumors. A total of 65% of patients responded to metformin as defined by a decrease in Ki-67 staining in their endometrial tumors post-treatment. Metformin decreased expression of phosphorylated (p)-AMPK (P = 0.00001), p-Akt (P = 0.0002), p-S6 (51.2%, P = 0.0002), p-4E-BP-1 (P = 0.001), and ER (P = 0.0002) but not PR expression. Metabolomic profiling of serum indicated that responders versus nonresponders to treatment were more sensitive to metformin's effects on induction of lipolysis, which correlated with increased fatty acid oxidation and glycogen metabolism in matched tumors. In conclusion, metformin reduced tumor proliferation in a pre-operative window study in obese EC patients, with dramatic effects on inhibition of the mTOR pathway. Metformin induced a shift in lipid and glycogen metabolism that was more pronounced in the serum and tumors of responders versus nonresponders to treatment.This study provides support for therapeutic clinical trials of metformin in obese patients with EC. PMID:25417601

  18. Antiproliferative and metabolic effects of metformin in a preoperative window clinical trial for endometrial cancer.

    PubMed

    Schuler, Kevin M; Rambally, Brooke S; DiFurio, Megan J; Sampey, Brante P; Gehrig, Paola A; Makowski, Liza; Bae-Jump, Victoria L

    2015-02-01

    We conducted a preoperative window study of metformin in endometrial cancer (EC) patients and evaluated its antiproliferative, molecular and metabolic effects. Twenty obese women with endometrioid EC were treated with metformin (850 mg) daily for up to 4 weeks prior to surgical staging. Expression of the proliferation marker Ki-67, estrogen receptor (ER), progesterone receptor (PR), adenosine monophosphate-activated protein kinase (AMPK), and downstream targets of the mammalian target of rapamycin (mTOR) pathway were measured by immunohistochemistry. Global, untargeted metabolomics analysis of serum pre- and postmetformin treatment, and matched tumor, was performed. Metformin reduced proliferation by 11.75% (P = 0.008) based on the comparison of pre- and posttreatment endometrial tumors. A total of 65% of patients responded to metformin as defined by a decrease in Ki-67 staining in their endometrial tumors post-treatment. Metformin decreased expression of phosphorylated (p)-AMPK (P = 0.00001), p-Akt (P = 0.0002), p-S6 (51.2%, P = 0.0002), p-4E-BP-1 (P = 0.001), and ER (P = 0.0002) but not PR expression. Metabolomic profiling of serum indicated that responders versus nonresponders to treatment were more sensitive to metformin's effects on induction of lipolysis, which correlated with increased fatty acid oxidation and glycogen metabolism in matched tumors. In conclusion, metformin reduced tumor proliferation in a pre-operative window study in obese EC patients, with dramatic effects on inhibition of the mTOR pathway. Metformin induced a shift in lipid and glycogen metabolism that was more pronounced in the serum and tumors of responders versus nonresponders to treatment.This study provides support for therapeutic clinical trials of metformin in obese patients with EC. PMID:25417601

  19. Metformin increases APP expression and processing via oxidative stress, mitochondrial dysfunction and NF-κB activation: Use of insulin to attenuate metformin's effect.

    PubMed

    Picone, Pasquale; Nuzzo, Domenico; Caruana, Luca; Messina, Elisa; Barera, Annalisa; Vasto, Sonya; Di Carlo, Marta

    2015-05-01

    Clinical and experimental biomedical studies have shown Type 2 diabetes mellitus (T2DM) to be a risk factor for the development of Alzheimer's disease (AD). This study demonstrates the effect of metformin, a therapeutic biguanide administered for T2DM therapy, on β-amyloid precursor protein (APP) metabolism in in vitro, ex vivo and in vivo models. Furthermore, the protective role of insulin against metformin is also demonstrated. In LAN5 neuroblastoma cells, metformin increases APP and presenilin levels, proteins involved in AD. Overexpression of APP and presenilin 1 (Pres 1) increases APP cleavage and intracellular accumulation of β-amyloid peptide (Aβ), which, in turn, promotes aggregation of Aβ. In the experimental conditions utilized the drug causes oxidative stress, mitochondrial damage, decrease of Hexokinase-II levels and cytochrome C release, all of which lead to cell death. Several changes in oxidative stress-related genes following metformin treatment were detected by PCR arrays specific for the oxidative stress pathway. These effects of metformin were found to be antagonized by the addition of insulin, which reduced Aβ levels, oxidative stress, mitochondrial dysfunction and cell death. Similarly, antioxidant molecules, such as ferulic acid and curcumin, are able to revert metformin's effect. Comparable results were obtained using peripheral blood mononuclear cells. Finally, the involvement of NF-κB transcription factor in regulating APP and Pres 1 expression was investigated. Upon metformin treatment, NF-κB is activated and translocates from the cytoplasm to the nucleus, where it induces increased APP and Pres 1 transcription. The use of Bay11-7085 inhibitor suppressed the effect of metformin on APP and Pres 1 expression. PMID:25667085

  20. Role of Organic Cation Transporter 3 (SLC22A3) and Its Missense Variants in the Pharmacologic Action of Metformin

    PubMed Central

    Chen, Ligong; Pawlikowski, Bradley; Schlessinger, Avner; More, Swati S.; Stryke, Doug; Johns, Susan J.; Portman, Michael A.; Chen, Eugene; Ferrin, Thomas E.; Sali, Andrej; Giacomini, Kathleen M.

    2010-01-01

    Objectives The goals of this study were to determine the role of OCT3 in the pharmacologic action of metformin and to identify and functionally characterize genetic variants of OCT3 with respect to the uptake of metformin and monoamines. Methods For the pharmacologic studies, we evaluated metformin-induced activation of AMPK, a molecular target of metformin. We used quantitative PCR and immunostaining to localize the transporter and isotopic uptake studies in cells transfected with OCT3 and its nonsynonymous genetic variants for functional analyses. Results Quantitative PCR and immunostaining showed that OCT3 was expressed high on the plasma membrane of skeletal muscle and liver, target tissues for metformin action. Both the OCT inhibitor, cimetidine, and OCT3-specific shRNA significantly reduced the activating effect of metformin on AMPK. To identify genetic variants in OCT3, we used recent data from the 1000 Genomes Project and the Pharmacogenomics of Membrane Transporters project. Six novel missense variants were identified. In functional assays, using various monoamines and metformin, 3 variants, T44M (c.131C>T), T400I (c.1199C>T) and V423F (c.1267G>T), showed altered substrate specificity. Notably, in cells expressing T400I and V423F, the uptakes of metformin and catecholamines were significantly reduced but the uptakes of metformin, MPP+ and histamine by T44M were significantly increased more than 50%. Structural modeling suggested that these two variants may be located in the pore-lining (T400) or proximal (V423) membrane-spanning helixes. Conclusion Our study suggests that OCT3 plays a role in the therapeutic action of metformin and that genetic variants of OCT3 may modulate metformin and catecholamine action. PMID:20859243

  1. Metformin inhibits mitochondrial permeability transition and cell death: a pharmacological in vitro study

    PubMed Central

    2004-01-01

    Metformin, a drug widely used in the treatment of Type II diabetes, has recently received attention owing to new findings regarding its mitochondrial and cellular effects. In the present study, the effects of metformin on respiration, complex 1 activity, mitochondrial permeability transition, cytochrome c release and cell death were investigated in cultured cells from a human carcinoma-derived cell line (KB cells). Metformin significantly decreased respiration both in intact cells and after permeabilization. This was due to a mild and specific inhibition of the respiratory chain complex 1. In addition, metformin prevented to a significant extent mitochondrial permeability transition both in permeabilized cells, as induced by calcium, and in intact cells, as induced by the glutathione-oxidizing agent t-butyl hydroperoxide. This effect was equivalent to that of cyclosporin A, the reference inhibitor. Finally, metformin impaired the t-butyl hydroperoxide-induced cell death, as judged by Trypan Blue exclusion, propidium iodide staining and cytochrome c release. We propose that metformin prevents the permeability transition-related commitment to cell death in relation to its mild inhibitory effect on complex 1, which is responsible for a decreased probability of mitochondrial permeability transition. PMID:15175014

  2. Metformin: the hidden chronicles of a magic drug.

    PubMed

    Mahmood, Khalid; Naeem, Muhammad; Rahimnajjad, Nasir Ali

    2013-01-01

    Metformin, a biguanide is well known treatment for type 2 diabetes mellitus that has diverse mechanism of actions. Various studies have elucidated the role of this drug in different pathologies. The well-known United Kingdom Prospective Diabetic Study (UKPDS) has observed its survival benefits in a large cohort of individuals. Data has been conclusive that metformin also has beneficial role in lipid disorders as it improves the markers of metabolic syndrome. Studies have also shown the beneficial roles in antipsychotic induced weight gain as well as HIV lipodystrophy syndrome. Evidence is accumulating that metformin also improves the fertility in females with Polycystic Ovarian Syndrome (PCOS). It also delays aging and is effective in aging related disorders and is equally effective in inflammation related disorders at least in different rodent studies. Metformin's major effect has been shown in various cancers ranging from solid to hematological malignancies. Researchers are working to reveal more benefits of this magic drug but it remains an unexplored territory for the medical community. PMID:23177353

  3. Protein S-Nitrosylation and Cardioprotection

    PubMed Central

    Sun, Junhui; Murphy, Elizabeth

    2010-01-01

    Nitric oxide (NO) plays an important role in the regulation of cardiovascular function. In addition to the classic NO activation of the cyclic guanosine monophosphate (cGMP)-dependent pathway, NO can also regulate cell function through protein S-nitrosylation, a redox dependent, thiol-based, reversible post-translational protein modification that involves attachment of an NO moiety to a nucleophilic protein sulfhydryl group. There are emerging data suggesting that S-nitrosylation of proteins plays an important role in cardioprotection. Protein S-nitrosylation not only leads to changes in protein structure and function, but also prevents these thiol(s) from further irreversible oxidative/nitrosative modification. A better understanding of the mechanism regulating protein S-nitrosylation and its role in cardioprotection will provide us new therapeutic opportunities and targets for interventions in cardiovascular diseases. PMID:20133913

  4. Identification of cardioprotective agents from traditional Chinese medicine against oxidative damage

    PubMed Central

    ZHOU, JIAN-MING; XU, ZHI-LIANG; LI, NA; ZHAO, YI-WU; WANG, ZHEN-ZHONG; XIAO, WEI

    2016-01-01

    Reactive oxygen species are damaging to cardiomyocytes. H9c2 cardiomyocytes are commonly used to study the cellular mechanisms and signal transduction in cardiomyocytes, and to evaluate the cardioprotective effects of drugs following oxidative damage. The present study developed a robust, automated high throughput screening (HTS) assay to identify cardioprotective agents from a traditional Chinese medicine (TCM) library using a H2O2-induced oxidative damage model in H9c2 cells. Using this HTS format, several hits were identified as cardioprotective by detecting changes to cell viability using the cell counting kit (CCK)-8 assay. Two TCM extracts, KY-0520 and KY-0538, were further investigated. The results of the present study demonstrated that treatment of oxidatively damaged cells with KY-0520 or KY-0538 markedly increased the cell viability and superoxide dismutase activity, decreased lactate dehydrogenase activity and malondialdehyde levels, and inhibited early growth response-1 (Egr-1) protein expression. The present study also demonstrated that KY-0520 or KY-0538 treatment protected H9c2 cells from H2O2-induced apoptosis by altering the Bcl-2/Bax protein expression ratio, and decreasing the levels of cleaved caspase-3. In addition, KY-0520 and KY-0538 reduced the phosphorylation of ERK1/2 and p38-MAPK proteins, and inhibited the translocation of Egr-1 from the cytoplasm to nucleus in H2O2-treated H9c2 cells. These findings suggested that oxidatively damaged H9c2 cells can be used for the identification of cardioprotective agents that reduce oxidative stress by measuring cell viabilities using CCK-8 in an HTS format. The underlying mechanism of the cardioprotective activities of KY-0520 and KY-0538 may be attributed to their antioxidative activity, regulation of Egr-1 and apoptosis-associated proteins, and the inhibition of ERK1/2, p38-MAPK and Egr-1 signaling pathways. PMID:27176126

  5. Effect of zinc supplements in the attenuated cardioprotective effect of ischemic preconditioning in hyperlipidemic rat heart.

    PubMed

    Kansal, Sunil Kumar; Jyoti, Uma; Sharma, Samridhi; Kaura, Arun; Deshmukh, Rahul; Goyal, Sandeep

    2015-06-01

    Hyperlipidemia is regarded as independent risk factor in the development of ischemic heart disease, and it can increase the myocardial susceptibility to ischemia-/reperfusion (I/R)-induced injury. Hyperlipidemia attenuates the cardioprotective response of ischemic preconditioning (IPC). The present study investigated the effect of zinc supplements in the attenuated cardioprotective effect of ischemic preconditioning in hyperlipidemic rat hearts. Hyperlipidemia was induced in rat by feeding high-fat diet (HFD) for 6 weeks then the serum lipid profile was observed. In experiment, the isolated Langendorff rat heart preparation was subjected to 4 cycles of ischemic preconditioning (IPC), then 30 min of ischemia followed by 120 min of reperfusion. Myocardial infarct size was elaborated morphologically by triphenyltetrazolium chloride (TTC) staining and biochemically by lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) release from coronary effluent and left ventricular collagen content. However, the effect of zinc supplement, i.e., zinc pyrithione (10 μM) perfused during reperfusion for 120 min, significantly abrogated the attenuated cardioprotective effect of ischemic preconditioning in hyperlipidemic rat heart whereas administration of chelator of this zinc ionophore, i.e., N,N,N',N'-tetrakis(2-pyridylmethyl)ethylene diamine (TPEN; 10 μM), perfused during reperfusion 2 min before the perfusion of zinc pyrithione abrogated the cardioprotective effect of zinc supplement during experiment in hyperlipidemic rat heart. Thus, the administration of zinc supplements limits the infarct size, LDH, and CK-MB and enhanced the collagen level which suggests that the attenuated cardioprotective effect of IPC in hyperlipidemic rat is due to zinc loss during reperfusion caused by ischemia/reperfusion. PMID:25743572

  6. Metformin inhibits the proliferation of human prostate cancer PC-3 cells via the downregulation of insulin-like growth factor 1 receptor

    SciTech Connect

    Kato, Haruo Sekine, Yoshitaka; Furuya, Yosuke; Miyazawa, Yoshiyuki; Koike, Hidekazu; Suzuki, Kazuhiro

    2015-05-22

    Metformin is a biguanide drug that is widely used for the treatment of type 2 diabetes. Recent studies have shown that metformin inhibits cancer cell proliferation and tumor growth both in vitro and in vivo. The anti-tumor mechanisms of metformin include activation of the AMP-activated protein kinase/mTOR pathway and direct inhibition of insulin/insulin-like growth factor (IGF)-mediated cellular proliferation. However, the anti-tumor mechanism in prostate cancer remains unclear. Because activation of the IGF-1 receptor (IGF-1R) is required for prostate cell proliferation, IGF-1R inhibitors may be of therapeutic value. Accordingly, we examined the effects of metformin on IGF-1R signaling in prostate cancer cells. Metformin significantly inhibited PC-3 cell proliferation, migration, and invasion. IGF-1R mRNA expression decreased significantly after 48 h of treatment, and IGF-1R protein expression decreased in a similar manner. IGF-1R knockdown by siRNA transfection led to inhibited proliferation, migration and invasion of PC-3 cells. IGF-1 activated both ERK1/2 and Akt, but these effects were attenuated by metformin treatment. In addition, intraperitoneal treatment with metformin significantly reduced tumor growth and IGF-1R mRNA expression in PC-3 xenografts. Our results suggest that metformin is a potent inhibitor of the IGF-1/IGF-1R system and may be beneficial in prostate cancer treatment. - Highlights: • Metformin inhibited PC-3 cell proliferation, migration, and invasion. • Metformin decreased IGF-1R mRNA and protein expressions in PC-3 cells. • Metformin inhibited IGF-1 induced ERK and Akt phosphorylations in PC-3 cells. • Metformin treatment inhibited PC-3 cell growth and IGF-1R expression in vivo. • Metformin may be a potent inhibitor of the IGF-1/IGF-1R signaling.

  7. Metformin and Rapamycin Reduce Pancreatic Cancer Growth in Obese Prediabetic Mice by Distinct MicroRNA-Regulated Mechanisms.

    PubMed

    Cifarelli, Vincenza; Lashinger, Laura M; Devlin, Kaylyn L; Dunlap, Sarah M; Huang, Jennifer; Kaaks, Rudolf; Pollak, Michael N; Hursting, Stephen D

    2015-05-01

    Metformin treatment is associated with a decreased risk and better prognosis of pancreatic cancer (PC) in patients with type 2 diabetes, but the mechanism of metformin's PC growth inhibition in the context of a prediabetic state is unknown. We used a Panc02 pancreatic tumor cell transplant model in diet-induced obese (DIO) C57BL/6 mice to compare the effects of metformin and the direct mammalian target of rapamycin (mTOR) inhibitor rapamycin on PC growth, glucose regulation, mTOR pathway signaling, and candidate microRNA (miR) expression. In DIO/prediabetic mice, metformin and rapamycin significantly reduced pancreatic tumor growth and mTOR-related signaling. The rapamycin effects centered on decreased mTOR-regulated growth and survival signaling, including increased expression of let-7b and cell cycle-regulating miRs. Metformin (but not rapamycin) reduced glucose and insulin levels and expression of miR-34a and its direct targets Notch, Slug, and Snail. Metformin also reduced the number and size of Panc02 tumor spheres in vitro and inhibited the expression of Notch in spheroids. Our results suggest that metformin and rapamycin can both inhibit pancreatic tumor growth in obese, prediabetic mice through shared and distinct mechanisms. Metformin and direct mTOR inhibitors, alone or possibly in combination, represent promising intervention strategies for breaking the diabetes-PC link. PMID:25576058

  8. Metformin displays anti-myeloma activity and synergistic effect with dexamethasone in in vitro and in vivo xenograft models.

    PubMed

    Zi, Fu-Ming; He, Jing-Song; Li, Yi; Wu, Cai; Yang, Li; Yang, Yang; Wang, Li-Juan; He, Dong-Hua; Zhao, Yi; Wu, Wen-Jun; Zheng, Gao-Feng; Han, Xiao-Yan; Huang, He; Yi, Qing; Cai, Zhen

    2015-01-28

    Epidemiologic studies and meta-analyses have suggested that patients with type 2 diabetes mellitus (T2DM) have a higher incidence of malignancies, including myeloma. Metformin is a widely prescribed antidiabetic drug. Recently, researchers have shown that metformin has direct anticancer activity against many tumor cell lines, mainly through activating AMP-activated protein kinase (AMPK) or reducing the blood insulin level. In the present study, we investigated whether metformin exerts an anti-myeloma effect in in vitro and in vivo xenograft models and explored the underlying mechanism. We found that metformin can inhibit proliferation of MM cells by inducing apoptosis and cell cycle arrest in the G0/G1 phase. Western blot showed that metformin activated caspase 3, caspase 9, PARP-1, Bak, and p21 and inactivated Mcl-1, HIAP-1, cyclin D1, CDK4, and CDK6. Metformin inhibited the expression of insulin growth factor-I receptor (IGF-IR), and phosphatidyl inositol 3-kinase (PI3K), protein kinase B (PKB/AKT) and the downstream mammalian target of rapamycin (mTOR). IGF-I blocked metformin-induced MM cell apoptosis and reactivation of the PI3K/AKT/mTOR signaling pathway. Metformin also demonstrated synergistic activity with dexamethasone but not bortezomib to eradicate MM cells in vitro and in vivo, especially in MM.1S cells. We conclude that metformin inhibits MM cell proliferation through the IGF-1R/PI3K/AKT/mTOR signaling pathway. Metformin and dexamethasone combination therapy may be an option for MM treatment. PMID:25305450

  9. The anorexigenic effects of metformin involve increases in hypothalamic leptin receptor expression.

    PubMed

    Aubert, Grégory; Mansuy, Virginie; Voirol, Marie-Jeanne; Pellerin, Luc; Pralong, François P

    2011-03-01

    Metformin demonstrates anorectic effects in vivo and inhibits neuropeptide Y expression in cultured hypothalamic neurons. Here we investigated the mechanisms implicated in the modulation of feeding by metformin in animals rendered obese by long-term high-fat diet (diet-induced obesity [DIO]) and in animals resistant to obesity (diet resistant [DR]). Male Long-Evans rats were kept on normal chow feeding (controls) or on high-fat diet (DIO, DR) for 6 months. Afterward, rats were treated 14 days with metformin (75 mg/kg) or isotonic sodium chloride solution and killed. Energy efficiency, metabolic parameters, and gene expression were analyzed at the end of the high-fat diet period and after 14 days of metformin treatment. At the end of the high-fat diet period, despite higher leptin levels, DIO rats had higher levels of hypothalamic neuropeptide Y expression than DR or control rats, suggesting a central leptin resistance. In DIO but also in DR rats, metformin treatment induced significant reductions of food intake accompanied by decreases in body weight. Interestingly, the weight loss achieved by metformin was correlated with pretreatment plasma leptin levels. This effect was paralleled by a stimulation of the expression of the leptin receptor gene (ObRb) in the arcuate nucleus. These data identify the hypothalamic ObRb as a gene modulated after metformin treatment and suggest that the anorectic effects of the drug are potentially mediated via an increase in the central sensitivity to leptin. Thus, they provide a rationale for novel therapeutic approaches associating leptin and metformin in the treatment of obesity. PMID:20303124

  10. Metformin: A therapeutic opportunity in breast cancer

    PubMed Central

    Gonzalez-Angulo, Ana M.; Meric-Bernstam, Funda

    2010-01-01

    Two important, related pathways are involved in cancer growth. The insulin/insulin-like growth factor-1 (IGF1) signaling pathway, which is activated when nutrients are available, and the adenosine mono-phosphateactivated protein kinase (AMPK) pathway, activated when cells are starved for carbohydrates. Metformin inhibits transcription of key gluconeogenesis genes in the liver, increases glucose uptake in skeletal muscle, and decreases circulating insulin levels. Metformin reduces levels of circulating glucose, increases insulin sensitivity, and reduces insulin resistance associated hyperinsulinemia. At the level of cell signaling, metformin activates AMPK. There are extensive pre-clinical data showing the anticancer effects of metformin in all breast cancer subtypes as well as in cytotoxic therapy-resistant models. These data, and the epidemiological and retrospective data supporting the antineoplastic effects of metformin, provide the rationale to study the role of metformin for breast cancer therapy in a variety of clinical settings. PMID:20215559

  11. Nebivolol: a multifaceted antioxidant and cardioprotectant in hypertensive heart disease.

    PubMed

    Khan, M Usman; Zhao, Wenyuan; Zhao, Tieqiang; Al Darazi, Fahed; Ahokas, Robert A; Sun, Yao; Bhattacharya, Syamal K; Gerling, Ivan C; Weber, Karl T

    2013-11-01

    Cardiomyocyte necrosis with attendant microscopic scarring is a pathological feature of human hypertensive heart disease (HHD). Understanding the pathophysiological origins of necrosis is integral to its prevention. In a rat model of HHD associated with aldosterone/salt treatment (ALDOST), myocyte necrosis is attributable to oxidative stress induced by cytosolic-free [Ca]i and mitochondrial [Ca]m overloading in which the rate of reactive oxygen species generation overwhelms their rate of detoxification by endogenous Zn-based antioxidant defenses. We hypothesized that nebivolol (Neb), unlike another β1 adrenergic receptor antagonist atenolol (Aten), would have a multifaceted antioxidant potential based on its dual property as a β3 receptor agonist, which activates endothelial nitric oxide synthase to stimulate nitric oxide (NO) generation. NO promotes the release of cytosolic Zn sequestered inactive by its binding protein, metallothionein. Given the reciprocal regulation between these cations, increased [Zn]i reduces Ca entry and attendant rise in [Ca]i and [Ca]m. Herein, we examined the antioxidant and cardioprotectant properties of Neb and Aten in rats receiving 4 weeks ALDOST. Compared with untreated age-/sex-matched controls, ALDOST alone or ALDOST with Aten, Neb cotreatment induced endothelial nitric oxide synthase activation, NO generation and a marked increase in [Zn]i with associated decline in [Ca]i and [Ca]m. Attendant antioxidant profile at subcellular and cellular levels included attenuation of mitochondrial H2O2 production and lipid peroxidation expressed as reduced 8-isoprostane concentrations in both mitochondria and cardiac tissue. Myocyte salvage was expressed as reduced microscopic scarring and tissue collagen volume fraction. Neb is a multifaceted antioxidant with unique properties as cardioprotectant in HHD. PMID:23921314

  12. Benefits of Metformin Use for Cholangiocarcinoma.

    PubMed

    Kaewpitoon, Soraya J; Loyd, Ryan A; Rujirakul, Ratana; Panpimanmas, Sukij; Matrakool, Likit; Tongtawee, Taweesak; Kootanavanichpong, Nusorn; Kompor, Ponthip; Chavengkun, Wasugree; Kujapun, Jirawoot; Norkaew, Jun; Ponphimai, Sukanya; Padchasuwan, Natnapa; Pholsripradit, Poowadol; Eksanti, Thawatchai; Phatisena, Tanida; Kaewpitoon, Natthawut

    2015-01-01

    Metformin is an oral anti-hyperglycemic agent, which is the most commonly prescribed medication in the treatment of type-2 diabetes mellitus. It is purportedly associated with a reduced risk for various cancers, mainly exerting anti-proliferation effects on various human cancer cell types, such as pancreas, prostate, breast, stomach and liver. This mini-review highlights the risk and benefit of metformin used for cholangiocarcinoma (CCA) prevention and therapy. The results indicated metformin might be a quite promising strategy CCA prevention and treatment, one mechanism being inhibition of CCA tumor growth by cell cycle arrest in both in vitro and in vivo. The AMPK/mTORC1 pathway in intrahepatic CCA cells is targeted by metformin. Furthermore, metformin inhibited CCA tumor growth via the regulation of Drosha-mediated expression of multiple carcinogenic miRNAs. The use of metformin seems to be safe in patients with cirrhosis, and provides a survival benefit. Once hepatic malignancies are already established, metformin does not offer any therapeutic potential. Clinical trials and epidemiological studies of the benefit of metformin use for CCA should be conducted. To date, whether metformin as a prospective chemotherapeutic for CCA is still questionable and waits further atttention. PMID:26745042

  13. Potential role for metformin in urologic oncology

    PubMed Central

    Sayyid, Rashid Khalid

    2016-01-01

    Metformin is one of the most commonly used drugs worldwide. It is currently considered first-line pharmacological agent for management of diabetes mellitus type 2. Recent studies have suggested that metformin may have further benefits, especially in the field of urologic oncology. Use of metformin has been shown to be associated with decreased incidence and improved outcomes of prostate, bladder, and kidney cancer. These studies suggest that metformin does have a future role in the prevention and management of urologic malignancies. In this review, we will discuss the latest findings in this field and its implications on the management of urologic oncology patients. PMID:27195314

  14. Regulation of tumor cell migration and invasion by the H19/let-7 axis is antagonized by metformin-induced DNA methylation.

    PubMed

    Yan, L; Zhou, J; Gao, Y; Ghazal, S; Lu, L; Bellone, S; Yang, Y; Liu, N; Zhao, X; Santin, A D; Taylor, H; Huang, Y

    2015-06-01

    The imprinted, developmentally regulated H19 long noncoding RNA has been implicated in the pathogenesis of diverse human cancers, but the underlying mechanisms have remained poorly understood. Here, we report that H19 promotes tumor cell migration and invasion by inhibiting let-7, a potent tumor suppressor microRNA that functions to posttranscriptionally suppress the expression of oncogenes that regulate cell growth and motility. We show that H19 depletion impairs, whereas its overexpression enhances the motility and invasiveness of tumor cells. These phenomena occur, at least in part through affecting let-7-mediated regulation of metastasis-promoting genes, including Hmga2, c-Myc and Igf2bp3. This H19/let-7-dependent regulation is recapitulated in vivo where co-expressions of oncogenes and H19 exist in both primary human ovarian and endometrial cancers. Furthermore, we provide evidence that the anti-diabetic drug metformin inhibits tumor cell migration and invasion, partly by downregulating H19 via DNA methylation. Our results reveal a novel mechanism underpinning H19-mediated regulation in metastasis and may explain why in some cases increased let-7 expression unexpectedly correlates with poor prognosis, given the widely accepted role for let-7 as a tumor suppressor. Targeting this newly identified pathway might offer therapeutic opportunities. PMID:25088204

  15. Metformin exerts glucose-lowering action in high-fat fed mice via attenuating endotoxemia and enhancing insulin signaling

    PubMed Central

    Zhou, Zi-yu; Ren, Li-wei; Zhan, Ping; Yang, Han-yan; Chai, Dan-dan; Yu, Zhi-wen

    2016-01-01

    Aim: Accumulating evidence shows that lipopolysaccharides (LPS) derived from gut gram-negative bacteria can be absorbed, leading to endotoxemia that triggers systemic inflammation and insulin resistance. In this study we examined whether metformin attenuated endotoxemia, thus improving insulin signaling in high-fat diet fed mice. Methods: Mice were fed a high-fat diet for 18 weeks to induce insulin resistance. One group of the mice was treated with oral metformin (100 mg·kg−1·d−1) for 4 weeks. Another group was treated with LPS (50 μg·kg−1·d−1, sc) for 5 days followed by the oral metformin for 10 d. Other two groups received a combination of antibiotics for 7 d or a combination of antibiotics for 7 d followed by the oral metformin for 4 weeks, respectively. Glucose metabolism and insulin signaling in liver and muscle were evaluated, the abundance of gut bacteria, gut permeability and serum LPS levels were measured. Results: In high-fat fed mice, metformin restored the tight junction protein occludin-1 levels in gut, reversed the elevated gut permeability and serum LPS levels, and increased the abundance of beneficial bacteria Lactobacillus and Akkermansia muciniphila. Metformin also increased PKB Ser473 and AMPK T172 phosphorylation, decreased MDA contents and redox-sensitive PTEN protein levels, activated the anti-oxidative Nrf2 system, and increased IκBα in liver and muscle of the mice. Treatment with exogenous LPS abolished the beneficial effects of metformin on glucose metabolism, insulin signaling and oxidative stress in liver and muscle of the mice. Treatment with antibiotics alone produced similar effects as metformin did. Furthermore, the beneficial effects of antibiotics were addictive to those of metformin. Conclusion: Metformin administration attenuates endotoxemia and enhances insulin signaling in high-fat fed mice, which contributes to its anti-diabetic effects. PMID:27180982

  16. Destabilization of MYC/MYCN by the mitochondrial inhibitors, metaiodobenzylguanidine, metformin and phenformin.

    PubMed

    Wang, Stephanie S; Hsiao, Ruth; Limpar, Mariko M; Lomahan, Sarah; Tran, Tuan-Anh; Maloney, Nolan J; Ikegaki, Naohiko; Tang, Xao X

    2014-01-01

    In the present study, we investigated the anticancer effects of the mitochondrial inhibitors, metaiodobenzylguanidine (MIBG), metformin and phenformin. 131I-MIBG has been used for scintigraphic detection and the targeted radiotherapy of neuroblastoma (NB), a pediatric malignancy. Non-radiolabeled MIBG has been reported to be cytotoxic to NB cells in vitro and in vivo. However, the mechanisms behind its growth suppressive effects have not yet been fully elucidated. Metformin and phenformin are diabetes medications that are being considered in anticancer therapeutics. We investigated the anticancer mechanisms of action of MIBG and metformin in NB. Our data revealed that both drugs suppressed NB cell growth and that the combination drug treatment was more potent. MIBG reduced MYCN and MYC expression in MYCN-amplified and non-MYCN-amplified NB cells in a dose- and time-dependent manner. Metformin was less effective than MIBG in destabilizing MYC/MYCN. The treatment of NB cells with metformin or MIBG resulted in an increased expression of genes encoding biomarkers for favorable outcome in NB [(ephrin (EFN)B2, EFNB3, EPH receptor B6 (EPHB6), neurotrophic tyrosine kinase, receptor, type 1 (NTRK1), CD44 and Myc-interacting zinc finger protein (MIZ-1)] and tumor suppressor genes [(early growth response 1 (EGR1), EPH receptor A2 (EPHA2), growth arrest and DNA-damage-inducible, beta (GADD45B), neuregulin 1 (NRG1), TP53 apoptosis effector (PERP) and sel-1 suppressor of lin-12-like (C. elegans) (SEL1L)]. Accordingly, metformin and MIBG augmented histone H3 acetylation in these cells. Phenformin also exhibited histone modification and was more effective than metformin in destabilizing MYC/MYCN in NB cells. Our data suggest that the destabilization of MYC/MYCN by MIBG, metformin and phenformin and their effects on histone modification are important mechanisms underlying their anticancer effects. PMID:24190252

  17. Hyperhomocysteinemia, deep vein thrombosis and vitamin B12 deficiency in a metformin-treated diabetic patient.

    PubMed

    Lin, Hsuan-Yu; Chung, Chih-Yuan; Chang, Cheng-Shyong; Wang, Ming-Lun; Lin, Jen-Shiou; Shen, Ming-Ching

    2007-09-01

    Vitamin B12 deficiency may be induced by long-term use of metformin, which may in turn lead to hyperhomocysteinemia. Thus, hyperhomocysteinemia may increase the risk of vascular thrombosis in diabetic patients, when metformin is used and a homozygous methylenetetrahydrofolate reductase (MTHFR) C677T mutation is present. We report a 65-year-old Taiwanese diabetic woman who was treated with metformin for 6 years and who had suffered from swelling of the left lower extremity for 3 months. Ascending venography confirmed the diagnosis of proximal deep vein thrombosis, while hyperhomocysteinemia, megaloblastic anemia caused by vitamin B12 deficiency, and a homozygous C677T mutation of the MTHFR gene were also found. She had no identifiable venous thrombotic risk factors other than hyperhomocysteinemia, which seemed to be caused by both MTHFR C677T homozygous mutation and vitamin B12 deficiency. With the substitution of insulin injection for metformin, short-term supplement of vitamin B12, and anticoagulant therapy for the deep vein thrombosis, her anemia and hyperhomocysteinemia recovered rapidly. The deep vein thrombosis also responded well. Our findings highly suggested the role of metformin in causing vitamin B12 deficiency, which may serve as an additional risk factor for venous thrombosis in diabetic patients. Our report also highlights the need to check vitamin B12 levels during metformin treatment. PMID:17908667

  18. Metformin inhibits cell cycle progression of B-cell chronic lymphocytic leukemia cells

    PubMed Central

    Bruno, Silvia; Ledda, Bernardetta; Tenca, Claudya; Ravera, Silvia; Orengo, Anna Maria; Mazzarello, Andrea Nicola; Pesenti, Elisa; Casciaro, Salvatore; Racchi, Omar; Ghiotto, Fabio; Marini, Cecilia; Sambuceti, Gianmario; DeCensi, Andrea; Fais, Franco

    2015-01-01

    B-cell chronic lymphocytic leukemia (CLL) was believed to result from clonal accumulation of resting apoptosis-resistant malignant B lymphocytes. However, it became increasingly clear that CLL cells undergo, during their life, iterative cycles of re-activation and subsequent clonal expansion. Drugs interfering with CLL cell cycle entry would be greatly beneficial in the treatment of this disease. 1, 1-Dimethylbiguanide hydrochloride (metformin), the most widely prescribed oral hypoglycemic agent, inexpensive and well tolerated, has recently received increased attention for its potential antitumor activity. We wondered whether metformin has apoptotic and anti-proliferative activity on leukemic cells derived from CLL patients. Metformin was administered in vitro either to quiescent cells or during CLL cell activation stimuli, provided by classical co-culturing with CD40L-expressing fibroblasts. At doses that were totally ineffective on normal lymphocytes, metformin induced apoptosis of quiescent CLL cells and inhibition of cell cycle entry when CLL were stimulated by CD40-CD40L ligation. This cytostatic effect was accompanied by decreased expression of survival- and proliferation-associated proteins, inhibition of signaling pathways involved in CLL disease progression and decreased intracellular glucose available for glycolysis. In drug combination experiments, metformin lowered the apoptotic threshold and potentiated the cytotoxic effects of classical and novel antitumor molecules. Our results indicate that, while CLL cells after stimulation are in the process of building their full survival and cycling armamentarium, the presence of metformin affects this process. PMID:26265439

  19. Metformin regulates ovarian angiogenesis and follicular development in a female polycystic ovary syndrome rat model.

    PubMed

    Di Pietro, Mariana; Parborell, Fernanda; Irusta, Griselda; Pascuali, Natalia; Bas, Diana; Bianchi, María Silvia; Tesone, Marta; Abramovich, Dalhia

    2015-04-01

    Polycystic ovary syndrome (PCOS) is a frequent pathology that affects more than 5% of women of reproductive age. Among other heterogeneous symptoms, PCOS is characterized by abnormalities in angiogenesis. Metformin has been introduced in the treatment of PCOS to manage insulin resistance and hyperglycemia. Besides its metabolic effects, metformin has been shown to improve ovulation, pregnancy and live birth rates in PCOS patients. In the present study, we used a dehydroepiandrosterone-induced PCOS rat model to analyze the effect of metformin administration on ovarian angiogenesis. We found that metformin was able to restore the increased levels of vascular endothelial growth factor, angiopoietin (ANGPT)1, and ANGPT1/ANGPT2 ratio and the decreased levels of platelet-derived growth factor B and platelet-derived growth factor D observed in the dehydroepiandrosterone-treated rats. These effects could take place, at least in part, through a decrease in the levels of serum insulin. We also found an improvement in follicular development, with a lower percentage of small follicles and cysts and a higher percentage of antral follicles and corpora lutea after metformin administration. The improvement in ovarian angiogenesis is likely to restore the accumulation of small follicles observed in PCOS rats and to reduce cyst formation, thus improving follicular development and the percentage of corpora lutea. These results open new insights into the study of metformin action not only in glucose metabolism but also in ovarian dysfunction in PCOS women. PMID:25590243

  20. Metformin inhibits cell growth by upregulating microRNA-26a in renal cancer cells.

    PubMed

    Yang, Feng-Qiang; Wang, Ji-Jiao; Yan, Jia-Sheng; Huang, Jian-Hua; Li, Wei; Che, Jian-Ping; Wang, Guang-Chun; Liu, Min; Zheng, Jun-Hua

    2014-01-01

    Accumulating evidence suggests that metformin, a biguanide class of anti-diabetic drugs, possesses anti-cancer properties and may reduce cancer risk and improve prognosis. However, the mechanism by which metformin affects various cancers, including renal cancer still unknown. MiR-26a induces cell growth, cell cycle and cell apoptosis progression via direct targeting of Bcl-2, clyclin D1 and PTEN in cancer cells. In the present study, we used 786-O human renal cancer cell lines to study the effects and mechanisms of metformin. Metformin treatment inhibited RCC cells proliferation by increasing expression of miR-26a in 786-O cells (P < 0.05). As a result, protein abundance of Bcl-2 and cyclin D1 was decreased and PTEN was increased in cells exposed to metformin. Also over-expression of miR-26a can inhibited cell proliferation by down-regulating Bcl-2, cyclin D1 and up-regulating PTEN expression. Therefore, these data for the first time provide novel evidence for a mechanism that the anticancer activities of metformin are due to upregulation of miR-26a and affect its downstream target gene. PMID:25419360

  1. Metformin reverses multidrug resistance in human hepatocellular carcinoma Bel‑7402/5‑fluorouracil cells.

    PubMed

    Ling, Sunbin; Tian, Yu; Zhang, Haiquan; Jia, Kaiqi; Feng, Tingting; Sun, Deguang; Gao, Zhenming; Xu, Fei; Hou, Zhaoyuan; Li, Yan; Wang, Liming

    2014-12-01

    Metformin exhibits anti‑proliferative effects in tumor cells in vitro and in vivo. The present study investigated the ability of metformin to reverse multidrug resistance (MDR) in human hepatocellular carcinoma Bel‑7402/5‑fluorouracil (5‑Fu; Bel/Fu) cells. The synergistic anti‑proliferative effect of metformin combined with 5‑Fu was evaluated using a Cell Counting kit‑8 assay. The variation in apoptotic rates and cell cycle distribution were evaluated using a flow cytometric assay and variations in target gene and protein expression were monitored using reverse transcription‑polymerase chain reaction and western blot analysis. The results demonstrated that metformin had a synergistic anti‑proliferative effect with 5‑Fu in the Bel/Fu cells. The variations in the number of apoptotic cells and distribution of the cell cycle were consistent with the variability in cell viability. Metformin targeted the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway, suppressed the expression of hypoxia‑inducible factor‑1α (HIF‑1α) and transcriptionally downregulated the expression of multidrug resistance protein 1/P‑glycoprotein (P‑gp) and multidrug resistance‑associated protein 1 (MRP1). Collectively, these findings suggested that metformin may target the AMPK/mTOR/HIF‑1α/P‑gp and MRP1 pathways to reverse MDR in hepatocellular carcinoma. PMID:25310259

  2. Carbon source and myc expression influence the antiproliferative actions of metformin.

    PubMed

    Javeshghani, Shiva; Zakikhani, Mahvash; Austin, Shane; Bazile, Miguel; Blouin, Marie-José; Topisirovic, Ivan; St-Pierre, Julie; Pollak, Michael N

    2012-12-01

    Epidemiologic and experimental data have led to increased interest in possible roles of biguanides in cancer prevention and/or treatment. Prior studies suggest that the primary action of metformin is inhibition of oxidative phosphorylation, resulting in reduced mitochondrial ATP production and activation of AMPK. In vitro, this may lead to AMPK-dependent growth inhibition if AMPK and its effector pathways are intact or to an energetic crisis if these are defective. We now show that the effect of exposure of several transformed cell lines to metformin varies with carbon source: in the presence of glutamine and absence of glucose, a 75% decrease in cellular ATP and an 80% decrease in cell number is typical; in contrast, when glucose is present, metformin exposure leads to increased glycolysis, with only a modest reduction in ATP level and cell number. Overexpression of myc was associated with sensitization to the antiproliferative effects of metformin, consistent with myc involvement in "glutamine addiction". Our results reveal previously unrecognized factors that influence metformin sensitivity and suggest that metformin-induced increase in glycolysis attenuates the antiproliferative effects of the compound. PMID:23041548

  3. Metformin exposure at environmentally relevant concentrations causes potential endocrine disruption in adult male fish.

    PubMed

    Niemuth, Nicholas J; Jordan, Renee; Crago, Jordan; Blanksma, Chad; Johnson, Rodney; Klaper, Rebecca D

    2015-02-01

    Pharmaceuticals and personal care products (PPCPs) are emerging contaminants that have been found ubiquitously in wastewater and surface waters around the world. A major source of these compounds is incomplete metabolism in humans and subsequent excretion in human waste, resulting in discharge into surface waters by wastewater treatment plant (WWTP) effluent. One pharmaceutical found in particularly high abundance in recent WWTP effluent and surface water studies is metformin, one of the world's most widely prescribed antidiabetic drugs. Interactions between insulin signaling and steroidogenesis suggest potential endocrine-disrupting effects of metformin found in the aquatic environment. Adult fathead minnows (Pimephales promelas) were chronically exposed to metformin for 4 wk, at 40 µg/L, a level similar to the average found in WWTP effluent in Milwaukee, Wisconsin, USA. Genetic endpoints related to metabolism and endocrine function as well as reproduction-related endpoints were examined. Metformin treatment induced significant up-regulation of messenger ribonucleic acid (mRNA) encoding the egg-protein vitellogenin in male fish, an indication of endocrine disruption. The present study, the first to study the effects of environmentally relevant metformin exposure in fathead minnows, demonstrates the need for further study of the endocrine-disrupting effects of metformin in aquatic organisms. PMID:25358780

  4. Metformin Exposure at Environmentally Relevant Concentrations Causes Potential Endocrine Disruption in Adult Male Fish

    PubMed Central

    Niemuth, Nicholas J; Jordan, Renee; Crago, Jordan; Blanksma, Chad; Johnson, Rodney; Klaper, Rebecca D

    2015-01-01

    Pharmaceuticals and personal care products (PPCPs) are emerging contaminants that have been found ubiquitously in wastewater and surface waters around the world. A major source of these compounds is incomplete metabolism in humans and subsequent excretion in human waste, resulting in discharge into surface waters by wastewater treatment plant (WWTP) effluent. One pharmaceutical found in particularly high abundance in recent WWTP effluent and surface water studies is metformin, one of the world's most widely prescribed antidiabetic drugs. Interactions between insulin signaling and steroidogenesis suggest potential endocrine-disrupting effects of metformin found in the aquatic environment. Adult fathead minnows (Pimephales promelas) were chronically exposed to metformin for 4 wk, at 40 µg/L, a level similar to the average found in WWTP effluent in Milwaukee, Wisconsin, USA. Genetic endpoints related to metabolism and endocrine function as well as reproduction-related endpoints were examined. Metformin treatment induced significant up-regulation of messenger ribonucleic acid (mRNA) encoding the egg-protein vitellogenin in male fish, an indication of endocrine disruption. The present study, the first to study the effects of environmentally relevant metformin exposure in fathead minnows, demonstrates the need for further study of the endocrine-disrupting effects of metformin in aquatic organisms. Environ Toxicol Chem 2014;9999:1–6. © 2014 The Authors. Published by Wiley Periodicals, Inc. on behalf of SETAC. PMID:25358780

  5. Metformin inhibits cell cycle progression of B-cell chronic lymphocytic leukemia cells.

    PubMed

    Bruno, Silvia; Ledda, Bernardetta; Tenca, Claudya; Ravera, Silvia; Orengo, Anna Maria; Mazzarello, Andrea Nicola; Pesenti, Elisa; Casciaro, Salvatore; Racchi, Omar; Ghiotto, Fabio; Marini, Cecilia; Sambuceti, Gianmario; DeCensi, Andrea; Fais, Franco

    2015-09-01

    B-cell chronic lymphocytic leukemia (CLL) was believed to result from clonal accumulation of resting apoptosis-resistant malignant B lymphocytes. However, it became increasingly clear that CLL cells undergo, during their life, iterative cycles of re-activation and subsequent clonal expansion. Drugs interfering with CLL cell cycle entry would be greatly beneficial in the treatment of this disease. 1, 1-Dimethylbiguanide hydrochloride (metformin), the most widely prescribed oral hypoglycemic agent, inexpensive and well tolerated, has recently received increased attention for its potential antitumor activity. We wondered whether metformin has apoptotic and anti-proliferative activity on leukemic cells derived from CLL patients. Metformin was administered in vitro either to quiescent cells or during CLL cell activation stimuli, provided by classical co-culturing with CD40L-expressing fibroblasts. At doses that were totally ineffective on normal lymphocytes, metformin induced apoptosis of quiescent CLL cells and inhibition of cell cycle entry when CLL were stimulated by CD40-CD40L ligation. This cytostatic effect was accompanied by decreased expression of survival- and proliferation-associated proteins, inhibition of signaling pathways involved in CLL disease progression and decreased intracellular glucose available for glycolysis. In drug combination experiments, metformin lowered the apoptotic threshold and potentiated the cytotoxic effects of classical and novel antitumor molecules. Our results indicate that, while CLL cells after stimulation are in the process of building their full survival and cycling armamentarium, the presence of metformin affects this process. PMID:26265439

  6. Metformin reverses multidrug resistance in human hepatocellular carcinoma Bel-7402/5-fluorouracil cells

    PubMed Central

    LING, SUNBIN; TIAN, YU; ZHANG, HAIQUAN; JIA, KAIQI; FENG, TINGTING; SUN, DEGUANG; GAO, ZHENMING; XU, FEI; HOU, ZHAOYUAN; LI, YAN; WANG, LIMING

    2014-01-01

    Metformin exhibits anti-proliferative effects in tumor cells in vitro and in vivo. The present study investigated the ability of metformin to reverse multidrug resistance (MDR) in human hepatocellular carcinoma Bel-7402/5-fluorouracil (5-Fu; Bel/Fu) cells. The synergistic anti-proliferative effect of metformin combined with 5-Fu was evaluated using a Cell Counting kit-8 assay. The variation in apoptotic rates and cell cycle distribution were evaluated using a flow cytometric assay and variations in target gene and protein expression were monitored using reverse transcription-polymerase chain reaction and western blot analysis. The results demonstrated that metformin had a synergistic anti-proliferative effect with 5-Fu in the Bel/Fu cells. The variations in the number of apoptotic cells and distribution of the cell cycle were consistent with the variability in cell viability. Metformin targeted the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway, suppressed the expression of hypoxia-inducible factor-1α (HIF-1α) and transcriptionally downregulated the expression of multidrug resistance protein 1/P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1). Collectively, these findings suggested that metformin may target the AMPK/mTOR/HIF-1α/P-gp and MRP1 pathways to reverse MDR in hepatocellular carcinoma. PMID:25310259

  7. Diet and tumor LKB1 expression interact to determine sensitivity to anti-neoplastic effects of metformin in vivo.

    PubMed

    Algire, C; Amrein, L; Bazile, M; David, S; Zakikhani, M; Pollak, M

    2011-03-10

    Hypothesis-generating epidemiological research has suggested that cancer burden is reduced in diabetics treated with metformin and experimental work has raised questions regarding the role of direct adenosine monophosphate-activated protein kinase (AMPK)-mediated anti-neoplastic effects of metformin as compared with indirect effects attributable to reductions in circulating insulin levels in the host. We treated both tumor LKB1 expression and host diet as variables, and observed that metformin inhibited tumor growth and reduced insulin receptor activation in tumors of mice with diet-induced hyperinsulinemia, independent of tumor LKB1 expression. In the absence of hyperinsulinemia, metformin inhibited only the growth of tumors transfected with short hairpin RNA against LKB1, a finding attributable neither to an effect on host insulin level nor to activation of AMPK within the tumor. Further investigation in vitro showed that cells with reduced LKB1 expression are more sensitive to metformin-induced adenosine triphosphate depletion owing to impaired ability to activate LKB1-AMPK-dependent energy-conservation mechanisms. Thus, loss of function of LKB1 can accelerate proliferation in contexts where it functions as a tumor suppressor, but can also sensitize cells to metformin. These findings predict that any clinical utility of metformin or similar compounds in oncology will be restricted to subpopulations defined by host insulin levels and/or loss of function of LKB1. PMID:21102522

  8. Cardioprotective activity of iron oxide nanoparticles

    PubMed Central

    Xiong, Fei; Wang, Hao; Feng, Yidong; Li, Yunman; Hua, Xiaoqing; Pang, Xingyun; Zhang, Song; Song, Lina; Zhang, Yu; Gu, Ning

    2015-01-01

    Iron oxide nanoparticles (IONPs) are chemically inert materials and have been mainly used for imaging applications and drug deliveries. However, the possibility whether they can be used as therapeutic drugs themselves has not yet been explored. We reported here that Fe2O3 nanoparticles (NPs) can protect hearts from ischemic damage at the animal, tissue and cell level. The cardioprotective activity of Fe2O3 NPs requires the integrity of nanoparticles and is not dependent upon their surface charges and molecules that were integrated into nanoparticles. Also, Fe2O3 NPs showed no significant toxicity towards normal cardiomyocytes, indicative of their potential to treat cardiovascular diseases. PMID:25716309

  9. Trimetazidine and cardioprotection: facts and perspectives.

    PubMed

    Tsioufis, Konstantinos; Andrikopoulos, George; Manolis, Athanasios

    2015-03-01

    Trimetazidine (TMZ) is a metabolic agent used in cardiology for more than 40 years. Several studies assessed the cardioprotective effects of TMZ in patients with chronic coronary heart disease (CHD) as well as in patients with heart failure (HF). In light of the inclusion of TMZ in the current guidelines on the management of stable CHD, we reviewed the published literature on TMZ, focusing mainly its effects on patients with stable angina and HF. According to the published literature, there is sufficient evidence to support the addition of this agent in the treatment of symptomatic patients with stable angina. PMID:24719262

  10. Clinical benefits of metformin in gynecologic oncology

    PubMed Central

    IMAI, ATSUSHI; ICHIGO, SATOSHI; MATSUNAMI, KAZUTOSHI; TAKAGI, HIROSHI; YASUDA, KEIGO

    2015-01-01

    Evidence has suggested that diabetes may contribute to the initiation and progression of specific types of cancer. Metformin, a biguanide, has become the preferred first-line therapy for the treatment of type 2 diabetes. Metformin is inexpensive, has a proven safety profile and is able to be safely combined with additional antidiabetic agents. In addition to the well-established antidiabetic effects of metformin, there has also been notable interest in its antitumor properties. The present review discusses the emerging role of metformin as an example of an existing drug, used worldwide in the treatment of diabetes, which has been demonstrated to exert significant in vitro and in vivo anticancer activities and has thus been investigated in clinical trials. In gynecologic oncology, metformin has been suggested to exhibit significant treatment efficacy against endometrial cancer. Three studies have demonstrated the potential therapeutic effects of metformin on the survival outcome of patients with ovarian cancer and in ovarian cancer prevention. However, this evidence was based on observational studies. Metformin has been shown to exert no statistically significant beneficial effect on cervical cancer incidence or mortality. By cancer site, the current limited insights highlight the need for clinical investigations and better-designed studies, along with evaluation of the effects of metformin on cancer at other sites. PMID:26622536

  11. Metformin suppresses CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating aryl hydrocarbon receptor expression

    SciTech Connect

    Do, Minh Truong; Kim, Hyung Gyun; Tran, Thi Thu Phuong; Khanal, Tilak; Choi, Jae Ho; Chung, Young Chul; Jeong, Tae Cheon; Jeong, Hye Gwang

    2014-10-01

    Induction of cytochrome P450 (CYP) 1A1 and CYP1B1 by environmental xenobiotic chemicals or endogenous ligands through the activation of the aryl hydrocarbon receptor (AhR) has been implicated in a variety of cellular processes related to cancer, such as transformation and tumorigenesis. Here, we investigated the effects of the anti-diabetes drug metformin on expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and inducible conditions. Our results indicated that metformin down-regulated the expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced conditions. Down-regulation of AhR expression was required for metformin-mediated decreases in CYP1A1 and CYP1B1 expression, and the metformin-mediated CYP1A1 and CYP1B1 reduction is irrelevant to estrogen receptor α (ERα) signaling. Furthermore, we found that metformin markedly down-regulated Sp1 protein levels in breast cancer cells. The use of genetic and pharmacological tools revealed that metformin-mediated down-regulation of AhR expression was mediated through the reduction of Sp1 protein. Metformin inhibited endogenous AhR ligand-induced CYP1A1 and CYP1B1 expression by suppressing tryptophan-2,3-dioxygenase (TDO) expression in MCF-7 cells. Finally, metformin inhibits TDO expression through a down-regulation of Sp1 and glucocorticoid receptor (GR) protein levels. Our findings demonstrate that metformin reduces CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating AhR signaling. Metformin would be able to act as a potential chemopreventive agent against CYP1A1 and CYP1B1-mediated carcinogenesis and development of cancer. - Graphical abstract: Schematic of the CYP1A1 and CYP1B1 gene regulation by metformin. - Highlights: • Metformin inhibits CYP1A1 and CYP1B1 expression. • Metformin down-regulates the AhR signaling. • Metformin reduces Sp1 protein expression. • Metformin suppresses TDO expression.

  12. Cholinesterase inhibitors: cardioprotection in Alzheimer's disease.

    PubMed

    Monacelli, Fiammetta; Rosa, Gianmarco

    2014-01-01

    Alzheimer's disease is a life shortening disease, and the lack of disease modifying therapy implies a huge impact on life expectancy as well as an outgrowing financial and socioeconomic burden. Cholinesterase inhibitors (ChEIs) represent the first line symptomatic therapy, whose benefit to harm ratio is still a matter of debate. Acetylcholinesterase enzyme is a core interest for pharmacological and toxicological research to unmask the fine balance between therapeutic drug efficacy, tolerability, safety, and detrimental effects up to adverse drug reaction. So far, a body of evidence advocated that an increased vagal tone was associated to an increased risk of gastrointestinal and cardiac side effects (negative chronotropic, arrhytmogenic, hypotensive effects), able to hamper ChEIs effects on cognition, reducing administration feasibility and compliance, especially in older and comorbid patients. Conversely, a growing body of evidence is indicating a protective role of ChEIs on overall cardiovascular mortality in patients with dementia, through a series of in vitro and in vivo investigations. The present review is aimed to report the up to date literature in the controversial field of ChEIs and cardioprotection in dementia, offering a state of the art, which may constitute the conceptual framework to be enlarged in order to build higher evidence. Chronic vagal nerve stimulation acted upon by donepezil might improve long term survival through pharmacological properties apart from cholinesterase inhibition, able to offer cardioprotection, abating the overall cardiovascular risk, and, thus profiling a new line of therapeutic intervention for ChEI drug class. PMID:25024324

  13. Adjuvant Cardioprotection in Cardiac Surgery: Update

    PubMed Central

    Wagner, Robert; Piler, Pavel; Gabbasov, Zufar; Maruyama, Junko; Maruyama, Kazuo; Nicovsky, Jiri

    2014-01-01

    Cardiac surgery patients are now more risky in terms of age, comorbidities, and the need for complex procedures. It brings about reperfusion injury, which leads to dysfunction and/or loss of part of the myocardium. These groups of patients have a higher incidence of postoperative complications and mortality. One way of augmenting intraoperative myocardial protection is the phenomenon of myocardial conditioning, elicited with brief nonlethal episodes of ischaemia-reperfusion. In addition, drugs are being tested that mimic ischaemic conditioning. Such cardioprotective techniques are mainly focused on reperfusion injury, a complex response of the organism to the restoration of coronary blood flow in ischaemic tissue, which can lead to cell death. Extensive research over the last three decades has revealed the basic mechanisms of reperfusion injury and myocardial conditioning, suggesting its therapeutic potential. But despite the enormous efforts that have been expended in preclinical studies, almost all cardioprotective therapies have failed in the third phase of clinical trials. One reason is that evolutionary young cellular mechanisms of protection against oxygen handling are not very robust. Ischaemic conditioning, which is among these, is also limited by this. At present, the prevailing belief is that such options of treatment exist, but their full employment will not occur until subquestions and methodological issues with the transfer into clinical practice have been resolved. PMID:25215293

  14. Mechanisms by Which Low Glucose Enhances the Cytotoxicity of Metformin to Cancer Cells Both In Vitro and In Vivo

    PubMed Central

    Haugrud, Allison B.; Miskimins, W. Keith

    2014-01-01

    Different cancer cells exhibit altered sensitivity to metformin treatment. Recent studies suggest these findings may be due in part to the common cell culture practice of utilizing high glucose, and when glucose is lowered, metformin becomes increasingly cytotoxic to cancer cells. In low glucose conditions ranging from 0 to 5 mM, metformin was cytotoxic to breast cancer cell lines MCF7, MDAMB231 and SKBR3, and ovarian cancer cell lines OVCAR3, and PA-1. MDAMB231 and SKBR3 were previously shown to be resistant to metformin in normal high glucose medium. When glucose was increased to 10 mM or above, all of these cell lines become less responsive to metformin treatment. Metformin treatment significantly reduced ATP levels in cells incubated in media with low glucose (2.5 mM), high fructose (25 mM) or galactose (25 mM). Reductions in ATP levels were not observed with high glucose (25 mM). This was compensated by enhanced glycolysis through activation of AMPK when oxidative phosphorylation was inhibited by metformin. However, enhanced glycolysis was either diminished or abolished by replacing 25 mM glucose with 2.5 mM glucose, 25 mM fructose or 25 mM galactose. These findings suggest that lowering glucose potentiates metformin induced cell death by reducing metformin stimulated glycolysis. Additionally, under low glucose conditions metformin significantly decreased phosphorylation of AKT and various targets of mTOR, while phospho-AMPK was not significantly altered. Thus inhibition of mTOR signaling appears to be independent of AMPK activation. Further in vivo studies using the 4T1 breast cancer mouse model confirmed that metformin inhibition of tumor growth was enhanced when serum glucose levels were reduced via low carbohydrate ketogenic diets. The data support a model in which metformin treatment of cancer cells in low glucose medium leads to cell death by decreasing ATP production and inhibition of survival signaling pathways. The enhanced cytotoxicity of metformin

  15. Anticancer effect of metformin on estrogen receptor-positive and tamoxifen-resistant breast cancer cell lines.

    PubMed

    Kim, Jinkyoung; Lee, Jiyun; Jang, Soon Young; Kim, Chungyeul; Choi, Yoojin; Kim, Aeree

    2016-05-01

    Acquisition of tamoxifen resistance (TR) during anti-estrogenic therapy using tamoxifen is a major obstacle in the treatment of estrogen receptor (ER)-positive breast cancer. As a biguanide derivative, metformin is commonly used to treat type II diabetes. It has recently emerged as a potential anticancer agent. The objective of the present study was to investigate the anticancer activity of metformin in relation to ERα expression and its signaling pathway in ERα-positive MCF-7 and MDA-MB-361 breast cancer cells as well as TR MCF-7 breast cancer cells. Metformin inhibited both protein and mRNA levels of ERα in the presence or absence of estrogen (E2) in the MCF-7, TR MCF-7 and MDA-MB-361 cells. Metformin repressed E2-inducible estrogen response element (ERE) luciferase activity, protein levels and mRNA levels of E2/ERα-regulated genes [including c-Myc, cyclin D1, progesterone receptor (PR) and pS2] to a greater degree than tamoxifen, resulting in inhibition of cell proliferation of MCF-7, TR MCF-7 and MDA-MB-361 cells. Collectively, our results suggest that one of the anticancer mechanisms of metformin could be attributable to the repression of expression and transcriptional activity of ERα. Metformin may be a good therapeutic agent for treating ERα-positive breast cancer by inhibiting the expression and function of ERα. In addition, metformin may be useful to treat tamoxifen-resistant breast cancer. PMID:26986571

  16. Insulin counter-regulatory factors, fibrinogen and C-reactive protein during olanzapine administration: effects of the antidiabetic metformin.

    PubMed

    Baptista, Trino; Sandia, Ignacio; Lacruz, Anny; Rangel, Nairy; de Mendoza, Soaira; Beaulieu, Serge; Contreras, Quilianio; Galeazzi, Tatiana; Vargas, Doritza

    2007-03-01

    In this study, the Authors assessed some insulin counter-regulatory factors, fibrinogen and C-reactive protein after olanzapine administration, and the effect of metformin on these variables, 37 patients with chronic schizophrenia were given olanzapine (10 mg/day for 14 weeks). Nineteen patients received metformin (850-2550 mg/day) and 18 received placebo in a randomized, double-blind protocol. The following variables were quantified before and after olanzapine: cortisol, leptin, tumor necrosis factor-alpha, glucagon, growth hormone, fibrinogen and C-reactive protein. Results were correlated with the changes in body weight and the insulin resistance index. We have reported elsewhere that metformin did not prevent olanzapine-induced weight gain, and the insulin resistance index significantly decreased after metformin and placebo; Baptista T, et al. Can J Psychiatry 2006; 51: 192-196. Cortisol, tumor necrosis factor-alpha and fibrinogen levels significantly decreased in both groups. Glucagon significantly increased after metformin (P=0.03). Leptin tended to increase after placebo (P=0.1) and displayed a small nonsignificant reduction after metformin. The C-reactive protein did not change significantly in any group. Contrarily to most published studies, olanzapine was associated with decreased insulin resistance. Decrements in cortisol, fibrinogen and tumor necrosis factor-alpha levels point to an improvement in the metabolic profile. The trend for leptin to increase after placebo, but not after metformin in spite of similar weight gain suggests a beneficial effect of this antidiabetic agent. PMID:17293706

  17. Metformin and gefitinib cooperate to inhibit bladder cancer growth via both AMPK and EGFR pathways joining at Akt and Erk

    PubMed Central

    Peng, Mei; Huang, Yanjun; Tao, Ting; Peng, Cai-Yun; Su, Qiongli; Xu, Wanjun; Darko, Kwame Oteng; Tao, Xiaojun; Yang, Xiaoping

    2016-01-01

    EGFR is a potential therapeutic target for treating bladder cancer, but has not been approved for clinical use yet. Metformin is a widely used antidiabetic drug and has demonstrated interesting anticancer effects on various cancer models, alone or in combination with chemotherapeutic drugs. The efficacy of gefitinib, a well-known EGFR tyrosine kinase inhibitor, combined with metformin was assessed on bladder cancer and underlying mechanisms were explored. This drug combination induced a strong anti-proliferative and anti-colony forming effect and apoptosis in bladder cancer cell lines. Gefitinib suppressed EGFR signaling and inhibited phosphorylation of ERK and Akt. Metformin amplified this inhibitory effect and enhanced gefitinib-induced activation of AMPK signaling pathway. In vivo intravesical treatment of metformin and gefitinib on syngeneic orthotopic mice confirmed the significant inhibitory effect on bladder tumor growth. These two drugs may be an excellent combination for the treatment of bladder cancer through intravesical instillation. PMID:27334428

  18. Addition of a Gastrointestinal Microbiome Modulator to Metformin Improves Metformin Tolerance and Fasting Glucose Levels

    PubMed Central

    Burton, Jeffrey H.; Johnson, Matthew; Johnson, Jolene; Hsia, Daniel S.; Greenway, Frank L.; Heiman, Mark L.

    2015-01-01

    Background: Adverse effects of metformin are primarily related to gastrointestinal (GI) intolerance that could limit titration to an efficacious dose or cause discontinuation of the medication. Because some metformin side effects may be attributable to shifts in the GI microbiome, we tested whether a GI microbiome modulator (GIMM) used in combination with metformin would ameliorate the GI symptoms. Methods: A 2-period crossover study design was used with 2 treatment sequences, either placebo in period 1 followed by GIMM in period 2 or vice versa. Study periods lasted for 2 weeks, with a 2-week washout period between. During the first week, type 2 diabetes patients (T2D) who experienced metformin GI intolerance took 500 mg metformin along with their assigned NM504 (GIMM) or placebo treatment with breakfast and with dinner. In the second week, the 10 subjects took 500 mg metformin (t.i.d.), with GIMM or placebo consumed with the first and third daily metformin doses. Subjects were permitted to discontinue metformin dosing if it became intolerable. Results: The combination of metformin and GIMM treatment produced a significantly better tolerance score to metformin than the placebo combination (6.78 ± 0.65 [mean ± SEM] versus 4.45 ± 0.69, P = .0006). Mean fasting glucose levels were significantly (P < .02) lower with the metformin–GIMM combination (121.3 ± 7.8 mg/dl) than with metformin-placebo (151.9 ± 7.8 mg/dl). Conclusion: Combining a GI microbiome modulator with metformin might allow the greater use of metformin in T2D patients and improve treatment of the disease. PMID:25802471

  19. Cardioprotection by remote ischemic preconditioning of the rat heart is mediated by extracellular vesicles.

    PubMed

    Giricz, Zoltán; Varga, Zoltán V; Baranyai, Tamás; Sipos, Péter; Pálóczi, Krisztina; Kittel, Ágnes; Buzás, Edit I; Ferdinandy, Péter

    2014-03-01

    Remote ischemic preconditioning (RIPC) of the heart is exerted by brief ischemic insults affected on a remote organ or a remote area of the heart before a sustained cardiac ischemia. To date, little is known about the inter-organ transfer mechanisms of cardioprotection by RIPC. Exosomes and microvesicles/microparticles are vesicles of 30-100 nm and 100-1000 nm in diameter, respectively (collectively termed extracellular vesicles [EVs]). Their content of proteins, mRNAs and microRNAs, renders EV ideal conveyors of inter-organ communication. However, whether EVs are involved in RIPC, is unknown. Therefore, here we investigated whether (1) IPC induces release of EVs from the heart, and (2) EVs are necessary for cardioprotection by RIPC. Hearts of male Wistar rats were isolated and perfused in Langendorff mode. A group of donor hearts was exposed to 3 × 5-5 min global ischemia and reperfusion (IPC) or 30 min aerobic perfusion, while coronary perfusates were collected. Coronary perfusates of these hearts were given to another set of recipient isolated hearts. A group of recipient hearts received IPC effluent depleted of EVs by differential ultracentrifugation. Infarct size was determined after 30 min global ischemia and 120 min reperfusion. The presence or absence of EVs in perfusates was confirmed by dynamic light scattering, the EV marker HSP60 Western blot, and electron microscopy. IPC markedly increased EV release from the heart as assessed by HSP60. Administration of coronary perfusate from IPC donor hearts attenuated infarct size in non-preconditioned recipient hearts (12.9 ± 1.6% vs. 25.0 ± 2.7%), similarly to cardioprotection afforded by IPC (7.3 ± 2.7% vs. 22.1 ± 2.9%) on the donor hearts. Perfusates of IPC hearts depleted of EVs failed to exert cardioprotection in recipient hearts (22.0 ± 2.3%). This is the first demonstration that EVs released from the heart after IPC are necessary for cardioprotection by RIPC, evidencing the importance of vesicular

  20. [Cardioprotective and antiarrhythmic properties of preparations from Leuzea carthamoides, Aralia mandshurica, and Eleutherococcus senticosus].

    PubMed

    Maslov, L N; Guzarova, N V

    2007-01-01

    It is established that pretreatment with Leuzea carthamoides extract (LCE) (1 ml/kg per os during 8 days) prevents the development of stress-induced (6-hr painful-emotional stress) damage of the rat heart. A chronic administration of LCE (1 ml/kg per os during 8 days) increased the cardiac tolerance to the cardiotoxic action of D, L-isoproterenol and the arrhythmogenic action of epinephrine. Pretreatment with naloxone (2 mg/kg) completely eliminated the cardioprotective effect LCE and attenuated but not abolished the antiarrhythmic effect of the phytoadaptogen. A chronic administration of LCE elevated the level of beta-endorphin levels in the rat blood plasma. It is suggested that the cardioprotective effect of LCE is related to an increase in the level of opioid peptides, which produce stimulation of the opioid receptors. It is also established that preliminary chronic administration of Aralia mandshurica extract (AME) increases the cardiac resistance to the arrhythmogenic action of a 45-min coronary artery occlusion, but has no effect on the necrosis/risk area ratio. A pretreatment with Eleutherococcus senticosus extract (ESE) (1 ml/kg per os during 8 days) prevented the stress-induced damages of the rat heart. A chronic administration of ESE increased the cardiac tolerance to the cardiotoxic action of D, L-isoproterenol and the arrhythmogenic action of epinephrine. The pretreatment with naloxone (2 mg/kg) completely eliminated both the cardioprotective action and the antiarrhythmic effect of the phytoadaptogen. A chronic administration of ESE increased the beta-endorphin level in the rat blood plasma. It is suggested that the cardioprotective and antiarrhythmic effects of ESE is also related to an increase in the endogenous opioid peptide levels. A chronic administration of ESE had no effect on the arrhythmogenic effect of a 45-min coronary artery occlusion and did not change the necrosis/risk area ratio in rats. PMID:18318196

  1. Targeting HIF-1α is a prerequisite for cell sensitivity to dichloroacetate (DCA) and metformin.

    PubMed

    Hong, Sung-Eun; Jin, Hyeon-Ok; Kim, Hyun-Ah; Seong, Min-Ki; Kim, Eun-Kyu; Ye, Sang-Kyu; Choe, Tae-Boo; Lee, Jin Kyung; Kim, Jong-Il; Park, In-Chul; Noh, Woo Chul

    2016-01-01

    Recently, targeting deregulated energy metabolism is an emerging strategy for cancer therapy. In the present study, combination of DCA and metformin markedly induced cell death, compared with each drug alone. Furthermore, the expression levels of glycolytic enzymes including HK2, LDHA and ENO1 were downregulated by two drugs. Interestingly, HIF-1α activation markedly suppressed DCA/metformin-induced cell death and recovered the expressions of glycolytic enzymes that were decreased by two drugs. Based on these findings, we propose that targeting HIF-1α is necessary for cancer metabolism targeted therapy. PMID:26616058

  2. Metformin repositioning as antitumoral agent: selective antiproliferative effects in human glioblastoma stem cells, via inhibition of CLIC1-mediated ion current

    PubMed Central

    Barbieri, Federica; Peretti, Marta; Pizzi, Erika; Pattarozzi, Alessandra; Carra, Elisa; Sirito, Rodolfo; Daga, Antonio; Curmi, Paul M.G.; Mazzanti, Michele; Florio, Tullio

    2014-01-01

    Epidemiological and preclinical studies propose that metformin, a first-line drug for type-2 diabetes, exerts direct antitumor activity. Although several clinical trials are ongoing, the molecular mechanisms of this effect are unknown. Here we show that chloride intracellular channel-1 (CLIC1) is a direct target of metformin in human glioblastoma cells. Metformin exposure induces antiproliferative effects in cancer stem cell-enriched cultures, isolated from three individual WHO grade IV human glioblastomas. These effects phenocopy metformin-mediated inhibition of a chloride current specifically dependent on CLIC1 functional activity. CLIC1 ion channel is preferentially active during the G1-S transition via transient membrane insertion. Metformin inhibition of CLIC1 activity induces G1 arrest of glioblastoma stem cells. This effect was time-dependent, and prolonged treatments caused antiproliferative effects also for low, clinically significant, metformin concentrations. Furthermore, substitution of Arg29 in the putative CLIC1 pore region impairs metformin modulation of channel activity. The lack of drugs affecting cancer stem cell viability is the main cause of therapy failure and tumor relapse. We identified CLIC1 not only as a modulator of cell cycle progression in human glioblastoma stem cells but also as the main target of metformin's antiproliferative activity, paving the way for novel and needed pharmacological approaches to glioblastoma treatment. PMID:25361004

  3. Is alcohol beneficial or harmful for cardioprotection?

    PubMed Central

    Garige, Mamatha; Gong, Maokai; Leckey, Leslie; Varatharajalu, Ravi; Zakhari, Samir

    2009-01-01

    While the effects of chronic ethanol consumption on liver have been well studied and documented, its effect on the cardiovascular system is bimodal. Thus, moderate drinking in many population studies is related to lower prevalence of coronary artery disease (CAD). In contrast, heavy drinking correlates with higher prevalence of CAD. In several other studies of cardiovascular mortalities, abstainers and heavy drinkers are at higher risk than light or moderate drinkers. The composite of this disparate relation in several population studies of cardiovascular mortality has been a “U-” or “J-”shaped curve. Apart from its ability to eliminate cholesterol from the intima of the arteries by reverse cholesterol transport, another major mechanism by which HDL may have this cardioprotective property is by virtue of the ability of its component enzyme paraoxonase1 (PON1) to inhibit LDL oxidation and/or inactivate OxLDL. Therefore, PON1 plays a central role in the disposal of OxLDL and thus is antiatherogenic. Furthermore, PON1 is a multifunctional antioxidant enzyme that can also detoxify the homocysteine metabolite, homocysteine thiolactone (HTL), which can pathologically cause protein damage by homocysteinylation of the lysine residues, thereby leading to atherosclerosis. We demonstrated that moderate alcohol up regulates liver PON1 gene expression and serum activity, whereas heavy alcohol consumption had the opposite effects in both animal models and in humans. The increase in PON1 activity in light drinkers was not due to preferential distribution of high PON1 genotype in this group. It is well known that wine consumption in several countries shows a remarkable inverse correlation to local rates of CAD mortality. Significantly, apart from its alcohol content, red wine also has polyphenols such as quercetin and resveratrol that are also known to have cardioprotective effects. We have shown that quercetin also up regulates PON1 gene in rats and in human liver cells

  4. Metformin in breast cancer - an evolving mystery.

    PubMed

    Camacho, Laura; Dasgupta, Atreyi; Jiralerspong, Sao

    2015-01-01

    Metformin, a diabetes drug with well-established side effect and safety profiles, has been widely studied for its anti-tumor activities in a number of cancers, including breast cancer. But its mechanism of action in the clinical arena remains elusive. In a window of opportunity trial of metformin in non-diabetic breast cancer patients, Dowling and colleagues examined both the direct actions of the drug on cancer cells (as mediated by AMP kinase), as well as its indirect actions (as mediated by circulating insulin). The data suggest that short-term administration of metformin in this setting has anti-tumor effects significantly involving the indirect, insulin-dependent pathway. The role of the direct pathway remains to be determined. This study represents an important step forward in establishing one of several possible mechanisms for metformin, information that will be useful in determining candidate biomarkers to evaluate in large clinical trials of metformin, such as the ongoing NCIC CTG MA.32 trial of adjuvant metformin. The potential significance of these data for metformin in the treatment of breast cancer is discussed here. PMID:26111812

  5. Metformin inhibits growth of human non-small cell lung cancer cells via liver kinase B-1-independent activation of adenosine monophosphate-activated protein kinase

    PubMed Central

    GUO, QIANQIAN; LIU, ZHIYAN; JIANG, LILI; LIU, MENGJIE; MA, JIEQUN; YANG, CHENGCHENG; HAN, LILI; NAN, KEJUN; LIANG, XUAN

    2016-01-01

    Metformin, the most widely administered oral anti-diabetic therapeutic agent, exerts its glucose-lowering effect predominantly via liver kinase B1 (LKB1)-dependent activation of adenosine monophosphate-activated protein kinase (AMPK). Accumulating evidence has demonstrated that metformin possesses potential antitumor effects. However, whether the antitumor effect of metformin is via the LKB1/AMPK signaling pathway remains to be determined. In the current study, the effects of metformin on proliferation, cell cycle progression, and apoptosis of human non-small cell lung cancer (NSCLC) H460 (LKB1-null) and H1299 (LKB1-positive) cells were assessed, and the role of LKB1/AMPK signaling in the anti-growth effects of metformin were investigated. Cell viability was determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, cell cycle distribution and apoptosis were assessed by flow cytometry, and protein expression levels were measured by western blotting. Metformin inhibited proliferation, induced significant cell cycle arrest at the G0–G1 phase and increased apoptosis in NSCLC cells in a time- and concentration-dependent manner, regardless of the level of LKB1 protein expression. Furthermore, knockdown of LKB1 with short hairpin RNA (shRNA) did not affect the antiproliferative effect of metformin in the H1299 cells. Metformin stimulated AMPK phosphorylation and subsequently suppressed the phosphorylation of mammalian target of rapamycin and its downstream effector, 70-kDa ribosomal protein S6 kinase in the two cell lines. These effects were abrogated by silencing AMPK with small interfering RNA (siRNA). In addition, knockdown of AMPK with siRNA inhibited the effect of metformin on cell proliferation in the two cell lines. These results provide evidence that the growth inhibition of metformin in NSCLC cells is mediated by LKB1-independent activation of AMPK, indicating that metformin may be a potential therapeutic agent for the treatment of

  6. Prolonged metformin treatment leads to reduced transcription of Nrf2 and neurotrophic factors without cognitive impairment in older C57BL/6J mice.

    PubMed

    Allard, Joanne S; Perez, Evelyn J; Fukui, Koji; Carpenter, Priscilla; Ingram, Donald K; de Cabo, Rafael

    2016-03-15

    Long-term use of anti-diabetic agents has become commonplace as rates of obesity, metabolic syndrome and diabetes continue to escalate. Metformin, a commonly used anti-diabetic drug, has been shown to have many beneficial effects outside of its therapeutic regulation of glucose metabolism and insulin sensitivity. Studies on metformin's effects on the central nervous system are limited and predominantly consist of in vitro studies and a few in vivo studies with short-term treatment in relatively young animals; some provide support for metformin as a neuroprotective agent while others show evidence that metformin may be deleterious to neuronal survival. In this study, we examined the effect of long-term metformin treatment on brain neurotrophins and cognition in aged male C57Bl/6 mice. Mice were fed control (C), high-fat (HF) or a high-fat diet supplemented with metformin (HFM) for 6 months. Metformin decreased body fat composition and attenuated declines in motor function induced by a HF diet. Performance in the Morris water maze test of hippocampal based memory function, showed that metformin prevented impairment of spatial reference memory associated with the HF diet. Quantitative RT-PCR on brain homogenates revealed decreased transcription of BDNF, NGF and NTF3; however protein levels were not altered. Metformin treatment also decreased expression of the antioxidant pathway regulator, Nrf2. The decrease in transcription of neurotrophic factors and Nrf2 with chronic metformin intake, cautions of the possibility that extended metformin use may alter brain biochemistry in a manner that creates a vulnerable brain environment and warrants further investigation. PMID:26698400

  7. Dietary energy availability affects primary and metastatic breast cancer and metformin efficacy

    PubMed Central

    Phoenix, Kathryn N.; Vumbaca, Frank; Fox, Melissa M.; Evans, Rebecca

    2010-01-01

    Dietary energy restriction has been shown to repress both mammary tumorigenesis and aggressive mammary tumor growth in animal studies. Metformin, a caloric restriction mimetic, has a long history of safe use as an insulin sensitizer in diabetics and has been shown to reduce cancer incidence and cancer-related mortality in humans. To determine the potential impact of dietary energy availability and metformin therapy on aggressive breast tumor growth and metastasis, an orthotopic syngeneic model using triple negative 66cl4 tumor cells in Balb/c mice was employed. The effect of dietary restriction, a standard maintenance diet or a diet with high levels of free sugar, were tested for their effects on tumor growth and secondary metastases to the lung. Metformin therapy with the various diets indicated that metformin can be highly effective at suppressing systemic metabolic biomarkers such as IGF-1, insulin and glucose, especially in the high energy diet treated animals. Long-term metformin treatment demonstrated moderate yet significant effects on primary tumor growth, most significantly in conjunction with the high energy diet. When compared to the control diet, the high energy diet promoted tumor growth, expression of the inflammatory adipokines leptin and resistin, induced lung priming by bone marrow-derived myeloid cells and promoted metastatic potential. Metformin had no effect on adipokine expression or the development of lung metastases with the standard or the high energy diet. These data indicate that metformin may have tumor suppressing activity where a metabolic phenotype of high fuel intake, metabolic syndrome, and diabetes exist, but may have little or no effect on events controlling the metastatic niche driven by proinflammatory events. PMID:20204498

  8. Effects of metformin and sitagliptin on glycolipid metabolism in type 2 diabetic rats on different diets

    PubMed Central

    Yang, Juhong; Ba, Tu; Chen, Liming; Shan, Chunyan; Zheng, Miaoyan; Wang, Ying; Ren, Huizhu; Chen, Jingli; Xu, Jie; Han, Fei; Zhang, Yi; Yang, Xiaoyun

    2016-01-01

    Introduction The aim of the study was to investigate the effects of metformin and sitagliptin on glycolipid metabolism in type 2 diabetes after different diets. Material and methods Seventy Male Sprague Dawley rats were fed with a high fat diet followed by streptozotocin treatment to induce type 2 diabetes. Then all rats were randomly divided into a control group, a metformin group (200 mg/kg), and a sitagliptin group (10 mg/kg). Each group was further divided into 4 groups receiving one load of high carbohydrate diet (45% glucose, 4.5 ml/kg), high fat diet (20% lipid emulsion, 4.5 ml/kg), high protein diet (20% whey protein, 10 ml/kg) or mixed meal, respectively. The caloric densities were all 33 kJ/kg. Postprandial blood glucose (P2BG), triglyceride (TG), glucagon-like peptide-1 (GLP-1), glucagon and insulin levels were measured. Results In the high carbohydrate group, sitagliptin was more efficient in lowering P2BG compared with metformin (p < 0.05). In the high-fat group, metformin was more powerful in lowering TG (p < 0.05) and P2BG (p < 0.05) levels because of its improvement of insulin sensitivity. In the high protein diet group, metformin did not reduce the P2BG level (p > 0.05), although it did reduce the TG level (p < 0.05). In the mixed diet group, metformin was more efficient in lowering P2BG (p < 0.05) but had a similar effect on TG (p > 0.05) compared with sitagliptin. Conclusions In the type 2 diabetic model, metformin and sitagliptin have different effects on glycolipid metabolism after different diets. If it is proved in type 2 diabetic patients, then different medicines may be recommended according to different diets in order to improve glycolipid metabolism. PMID:27186166

  9. Transcriptomic analysis of pancreatic cancer cells in response to metformin and aspirin: an implication of synergy

    PubMed Central

    Yue, Wen; Wang, Tao; Zachariah, Emmanuel; Lin, Yong; Yang, Chung S.; Xu, Qing; DiPaola, Robert S.; Tan, Xiang-Lin

    2015-01-01

    Metformin and aspirin have been studied extensively as cancer preventative and therapeutic agents. However, the underlying molecular mechanisms for the inhibitory effects of pancreatic cancer development remain undefined. To gain further insight into their biological function in pancreatic cancer, we conducted a transcriptomic analysis using RNA sequencing to assess the differential gene expression induced by metformin (5 mM) and aspirin (2 mM), alone or in combination, after treatment of PANC-1 cells for 48 hours. Compared to an untreated control, metformin down-regulated 58 genes and up-regulated 91 genes, aspirin down-regulated 12 genes only, while metformin plus aspirin down-regulated 656 genes and up-regulated 449 genes (fold-change > 2, P < 10−5). Of the top 10 genes (fold-change > 10, P < 10−10) regulated by metformin plus aspirin, PCDH18, CCL2, RASL11A, FAM111B and BMP5 were down-regulated ≥ 20-fold, while NGFR, NPTX1, C7orf57, MRPL23AS1 and UNC5B were up-regulated ≥ 10-fold. Ingenuity Pathway Analysis (IPA) revealed that the pathways, “cholesterol biosynthesis”, “cell cycle: G1/S checkpoint regulation”, and “axonal guidance signaling” were the most statistically significant pathways modulated by metformin plus aspirin. Although the results need further functional validation, these data provide the first evidence for the synergistic action between metformin and aspirin in modulating the transcriptional profile of pancreatic cancer cells. PMID:26294325

  10. Metformin suppresses CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating aryl hydrocarbon receptor expression.

    PubMed

    Do, Minh Truong; Kim, Hyung Gyun; Tran, Thi Thu Phuong; Khanal, Tilak; Choi, Jae Ho; Chung, Young Chul; Jeong, Tae Cheon; Jeong, Hye Gwang

    2014-10-01

    Induction of cytochrome P450 (CYP) 1A1 and CYP1B1 by environmental xenobiotic chemicals or endogenous ligands through the activation of the aryl hydrocarbon receptor (AhR) has been implicated in a variety of cellular processes related to cancer, such as transformation and tumorigenesis. Here, we investigated the effects of the anti-diabetes drug metformin on expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and inducible conditions. Our results indicated that metformin down-regulated the expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced conditions. Down-regulation of AhR expression was required for metformin-mediated decreases in CYP1A1 and CYP1B1 expression, and the metformin-mediated CYP1A1 and CYP1B1 reduction is irrelevant to estrogen receptor α (ERα) signaling. Furthermore, we found that metformin markedly down-regulated Sp1 protein levels in breast cancer cells. The use of genetic and pharmacological tools revealed that metformin-mediated down-regulation of AhR expression was mediated through the reduction of Sp1 protein. Metformin inhibited endogenous AhR ligand-induced CYP1A1 and CYP1B1 expression by suppressing tryptophan-2,3-dioxygenase (TDO) expression in MCF-7 cells. Finally, metformin inhibits TDO expression through a down-regulation of Sp1 and glucocorticoid receptor (GR) protein levels. Our findings demonstrate that metformin reduces CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating AhR signaling. Metformin would be able to act as a potential chemopreventive agent against CYP1A1 and CYP1B1-mediated carcinogenesis and development of cancer. PMID:25110054

  11. MITOCHONDRIA-TARGETED CARDIOPROTECTION IN ALDOSTERONISM

    PubMed Central

    Shahbaz, Atta U.; Kamalov, German; Zhao, Wenyuan; Zhao, Tieqiang; Johnson, Patti L.; Sun, Yao; Bhattacharya, Syamal K.; Ahokas, Robert A.; Gerling, Ivan C.; Weber, Karl T.

    2010-01-01

    Chronic aldosterone/salt treatment (ALDOST) is accompanied by an adverse structural remodeling of myocardium that includes multiple foci of microscopic scarring representing morphologic footprints of cardiomyocyte necrosis. Our previous studies suggested that signal-transducer-effector pathway leading to necrotic cell death during ALDOST includes intramitochondrial Ca2+ overloading, together with an induction of oxidative stress and opening of the mitochondrial permeability transition pore (mPTP). To further validate this concept, we hypothesized mitochondria-targeted interventions will prove cardioprotective. Accordingly, 8-wk-old male Sprague-Dawley rats receiving 4 wks ALDOST were cotreated with either quercetin (Q), a flavonoid with mitochondrial antioxidant properties, or cyclosporine A (CsA), an mPTP inhibitor, and compared to ALDOST alone or untreated, age-/sex-matched controls. We monitored: mitochondrial free Ca2+ and biomarkers of oxidative stress, including 8-isoprostane and H2O2 production; mPTP opening; total Ca2+ in cardiac tissue; collagen volume fraction (CVF) to quantify replacement fibrosis, a biomarker of cardiomyocyte necrosis; and employed TUNEL assay to address apoptosis in coronal sections of ventricular myocardium. Compared to controls, at 4 wks ALDOST we found: a marked increase in mitochondrial H2O2 production and 8-isoprostane levels, an increased propensity for mPTP opening, and greater concentrations of mitochondrial free [Ca2+]m and total tissue Ca2+, coupled with a 5-fold rise in CVF without any TUNEL-based evidence of cardiomyocyte apoptosis. Each of these pathophysiologic responses to ALDOST were prevented by Q or CsA cotreatment. Thus, mitochondria play a central role in initiating the cellular-molecular pathway that leads to necrotic cell death and myocardial scarring. This destructive cycle can be interrupted and myocardium salvaged with its structure preserved by mitochondria-targeted cardioprotective strategies. PMID:20966765

  12. Metformin reduces lipid accumulation in macrophages by inhibiting FOXO1-mediated transcription of fatty acid-binding protein 4

    SciTech Connect

    Song, Jun; Ren, Pingping; Zhang, Lin; Wang, Xing Li; Chen, Li; Shen, Ying H.

    2010-02-26

    Objective: The accumulation of lipids in macrophages contributes to the development of atherosclerosis. Strategies to reduce lipid accumulation in macrophages may have therapeutic potential for preventing and treating atherosclerosis and cardiovascular complications. The antidiabetic drug metformin has been reported to reduce lipid accumulation in adipocytes. In this study, we examined the effects of metformin on lipid accumulation in macrophages and investigated the mechanisms involved. Methods and results: We observed that metformin significantly reduced palmitic acid (PA)-induced intracellular lipid accumulation in macrophages. Metformin promoted the expression of carnitine palmitoyltransferase I (CPT-1), while reduced the expression of fatty acid-binding protein 4 (FABP4) which was involved in PA-induced lipid accumulation. Quantitative real-time PCR showed that metformin regulates FABP4 expression at the transcriptional level. We identified forkhead transcription factor FOXO1 as a positive regulator of FABP4 expression. Inhibiting FOXO1 expression with FOXO1 siRNA significantly reduced basal and PA-induced FABP4 expression. Overexpression of wild-type FOXO1 and constitutively active FOXO1 significantly increased FABP4 expression, whereas dominant negative FOXO1 dramatically decreased FABP4 expression. Metformin reduced FABP4 expression by promoting FOXO1 nuclear exclusion and subsequently inhibiting its activity. Conclusions: Taken together, these results suggest that metformin reduces lipid accumulation in macrophages by repressing FOXO1-mediated FABP4 transcription. Thus, metformin may have a protective effect against lipid accumulation in macrophages and may serve as a therapeutic agent for preventing and treating atherosclerosis in metabolic syndrome.

  13. Metabolites derived from omega-3 polyunsaturated fatty acids are important for cardioprotection.

    PubMed

    Gilbert, Kim; Malick, Mandy; Madingou, Ness; Touchette, Charles; Bourque-Riel, Valérie; Tomaro, Leandro; Rousseau, Guy

    2015-12-15

    Although controversial, some data suggest that omega-3 polyunsaturated fatty acids (PUFA) are beneficial to cardiovascular diseases, and could reduce infarct size. In parallel, we have reported that the administration of Resolvin D1 (RvD1), a metabolite of docosahexaenoic acid, an omega-3 PUFA, can reduce infarct size. The present study was designed to determine if the inhibition of two important enzymes involved in the formation of RvD1 from omega-3 PUFA could reduce the cardioprotective effect of omega-3 PUFA. Sprague-Dawley rats were fed with a diet rich in omega-3 PUFA during 10 days before myocardial infarction (MI). Two days before MI, rats received a daily dose of Meloxicam, an inhibitor of cyclooxygenase-2, PD146176, an inhibitor of 15-lipoxygenase, both inhibitors or vehicle. MI was induced by the occlusion of the left coronary artery for 40min followed by reperfusion. Infarct size and neutrophil accumulation were evaluated after 24h of reperfusion while caspase-3, -8 and Akt activities were assessed at 30min of reperfusion. Rats receiving inhibitors, alone or in combination, showed a larger infarct size than those receiving omega-3 PUFA alone. Caspase-3 and -8 activities are higher in ischemic areas with inhibitors while Akt activity is diminished in groups treated with inhibitors. Moreover, the study showed that RvD1 restores cardioprotection when added to the inhibitors. Results from this study indicate that the inhibition of the metabolism of Omega-3 PUFA attenuate their cardioprotective properties. Then, resolvins seem to be an important mediator in the cardioprotection conferred by omega-3 PUFA in our experimental model of MI. PMID:26550951

  14. A critical review on the translational journey of cardioprotective therapies!

    PubMed

    Rossello, Xavier; Yellon, Derek M

    2016-10-01

    The failure to translate novel cardioprotective therapies tested in pre-clinical studies into the clinical setting for patient benefit can be attributed to a number of factors at different stages of the research process. This review focuses on the evidences and the gaps with regard to the translational journey of cardioprotective interventions. Gaps are classified into 3 main groups: 1) those related to pre-clinical studies, 2) those associated with the validation of infarct size as a good surrogate and 3) those based on design and interpretation of randomized clinical trials on cardioprotection. Addressing these gaps might increase the chances to successfully translate cardioprotective therapies into improving both post-STEMI heart failure and cardiovascular death rates. PMID:27379920

  15. Metformin prevents hepatic steatosis by regulating the expression of adipose differentiation-related protein

    PubMed Central

    LIU, FANG; WANG, CHAO; ZHANG, LIJUN; XU, YUQIAO; JANG, LINA; GU, YU; CAO, XIANGMEI; ZHAO, XIN; YE, JING; LI, QING

    2014-01-01

    Non-alcoholic fatty liver disease (NAFLD) is a common liver disease, characterized by the excess accumulation of lipids in the liver. It has been demonstrated that the dysregulation of lipid droplet (LD)-associated proteins may be involved in the development of NAFLD. Adipose differentiation-related protein (ADRP), as one of the major LD-associated proteins, is expressed in normal and steatotic livers; however, the exact role of ADRP in the liver remains unknown. Previous studies have indicated that metformin, as an antidiabetic drug, effectively ameliorates NAFLD. However, its cellular and molecular mechanisms of action remain to be elucidated. Therefore, the aim of this study was to determine the role of ADRP in the metformin-mediated regulation of hepatic steatosis. We examined the effects of meformin in vivo and in vitro using ob/ob mice and primary hepatocytes, respectively. Lipid accumulation in the hepatocytes was induced by treatment with oleate. Our results revealed that metformin prevented hepatic steatosis in ob/ob mice and inhibited oleate-induced lipid accumulation in primary hepatocytes. Furthermore, using real-time PCR and western blot analysis, we examined the mRNA and protein expression of ADRP, respectively. We found that metformin significantly decreased the expression levels of ADRP. In addition, to further clarify the role of ADRP in lipid accumulation, we generated recombinant adenoviruses to induce the overexpression of ADRP and to knockdown ADRP. In the hepatocytes in which ADRP was overexpressed, the reducing effects of metformin on lipid accumulation were diminished. However, the knockdown of ADRP using siRNA targeting ADRP reduced the accumulation of triglycerides. Taken together, our data demonstrate that metformin prevents hepatic steatosis by regulating the expression of ADRP, which may be a key target in the treatment of NAFLD. PMID:24253218

  16. Skeletal muscle lactate overproduction during metformin intoxication: An animal study with reverse microdialysis.

    PubMed

    Protti, Alessandro; Properzi, Paolo; Magnoni, Sandra; Santini, Alessandro; Langer, Thomas; Guenzani, Silvia; Ferrero, Stefano; Bassani, Giulia; Stocchetti, Nino; Gattinoni, Luciano

    2016-07-25

    Lactic acidosis during metformin intoxication is classically mainly attributed to diminished lactate clearance through liver gluconeogenesis. Here we studied 6 healthy, sedated and mechanically ventilated pigs to clarify whether high dose of metformin also increases skeletal muscle lactate production. Each animal had two microdialysis catheters inserted in gluteus muscles, one per side. One catheter was infused with saline (control) while the other one was infused with metformin diluted in saline (1M), both at a rate of 0.3μl/min. Dialysate lactate concentration and lactate-to-pyruvate ratio, a marker of the balance between anaerobic glycolysis and aerobic (mitochondrial) metabolism, were measured every 3h, for 12h. Continuous infusion of metformin caused a progressive rise in dialysate lactate level (p=0.007) and lactate-to-pyruvate ratio (p<0.001) compared to that of saline, as for mitochondrial "poisoning". These findings suggest that skeletal muscle lactate overproduction contributes to the development of metformin-induced lactic acidosis. PMID:27178268

  17. PolyMetformin combines carrier and anticancer activities for in vivo siRNA delivery

    PubMed Central

    Zhao, Yi; Wang, Wei; Guo, Shutao; Wang, Yuhua; Miao, Lei; Xiong, Yang; Huang, Leaf

    2016-01-01

    Metformin, a widely implemented anti-diabetic drug, exhibits potent anticancer efficacies. Herein a polymeric construction of Metformin, PolyMetformin (PolyMet) is successfully synthesized through conjugation of linear polyethylenimine (PEI) with dicyandiamide. The delocalization of cationic charges in the biguanide groups of PolyMet reduces the toxicity of PEI both in vitro and in vivo. Furthermore, the polycationic properties of PolyMet permits capture of siRNA into a core-membrane structured lipid-polycation-hyaluronic acid (LPH) nanoparticle for systemic gene delivery. Advances herein permit LPH-PolyMet nanoparticles to facilitate VEGF siRNA delivery for VEGF knockdown in a human lung cancer xenograft, leading to enhanced tumour suppressive efficacy. Even in the absence of RNAi, LPH-PolyMet nanoparticles act similarly to Metformin and induce antitumour efficacy through activation of the AMPK and inhibition of the mTOR. In essence, PolyMet successfully combines the intrinsic anticancer efficacy of Metformin with the capacity to carry siRNA to enhance the therapeutic activity of an anticancer gene therapy. PMID:27264609

  18. Metformin prevents aggressive ovarian cancer growth driven by high-energy diet: similarity with calorie restriction.

    PubMed

    Al-Wahab, Zaid; Mert, Ismail; Tebbe, Calvin; Chhina, Jasdeep; Hijaz, Miriana; Morris, Robert T; Ali-Fehmi, Rouba; Giri, Shailendra; Munkarah, Adnan R; Rattan, Ramandeep

    2015-05-10

    Caloric restriction (CR) was recently demonstrated by us to restrict ovarian cancer growth in vivo. CR resulted in activation of energy regulating enzymes adenosine monophosphate activated kinase (AMPK) and sirtuin 1 (SIRT1) followed by downstream inhibition of Akt-mTOR. In the present study, we investigated the effects of metformin on ovarian cancer growth in mice fed a high energy diet (HED) and regular diet (RD) and compared them to those seen with CR in an immunocompetent isogeneic mouse model of ovarian cancer. Mice either on RD or HED diet bearing ovarian tumors were treated with 200 mg/kg metformin in drinking water. Metformin treatment in RD and HED mice resulted in a significant reduction in tumor burden in the peritoneum, liver, kidney, spleen and bowel accompanied by decreased levels of growth factors (IGF-1, insulin and leptin), inflammatory cytokines (MCP-1, IL-6) and VEGF in plasma and ascitic fluid, akin to the CR diet mice. Metformin resulted in activation of AMPK and SIRT1 and inhibition of pAkt and pmTOR, similar to CR. Thus metformin can closely mimic CR's tumor suppressing effects by inducing similar metabolic changes, providing further evidence of its potential not only as a therapeutic drug but also as a preventive agent. PMID:25895126

  19. Combined use of vitamin D3and metformin exhibits synergistic chemopreventive effects on colorectal neoplasia in rats and mice

    PubMed Central

    Li, Wan; Wang, Qi-Long; Liu, Xia; Dong, Shu-Hong; Li, Hong-Xia; Li, Chun-Yang; Guo, Li-Shu; Gao, Jing-Miao; Berger, Nathan A.; Li, Li; Ma, Lan; Wu, Yong-Jie

    2015-01-01

    Vitamin D3 and metformin are widely used in humans for regulating mineral metabolism and as an anti-diabetic drug respectively; and both of them have been shown to have chemopreventive effects against various tumors. This study was designed to investigate the potential synergistic chemopreventive effects of vitamin D3 and metformin against the development of early colon neoplasia in two models. The first model was a 1, 2-dimethylhydrazine dihydrochloride (DMH) induced colon cancer rat model and the second, a DMH-dextran sodium sulfate (DSS) induced colitis-associated colon neoplasia mouse model. Compared to either vitamin D3 or metformin alone, combined use of vitamin D3 and metformin showed more pronounced effect in reducing the numbers of aberrant crypt foci (ACF) and tumor in the colon. The most prominent inhibitory effects were observed in the vitamin D3 medium dose (100 IU/kg/day) and metformin medium dose (120 mg/kg/day) combination group. Furthermore, our results showed that enhancement of metformin’s chemopreventive effects by vitamin D3 was associated with down-regulation of S6P expression, via the AMPK (IGF-1)/mTOR pathway. In addition, and enhancement of vitamin D3’s chemopreventive effects by metformin was associated with inhibition of the protein expressions of c-Myc and Cyclin D1, via the vitamin D receptor/β-catenin pathway. These findings show that combined use of vitamin D3 and metformin exhibits synergistic effects against the development of early colon neoplasia. They suggest that the combined use of vitamin D3 and metformin may represent a novel strategy for chemoprevention of colorectal cancer. PMID:25416412

  20. Mutual inhibition of insulin signaling and PHLPP-1 determines cardioprotective efficiency of Akt in aged heart.

    PubMed

    Xing, Yuan; Sun, Wanqing; Wang, Yishi; Gao, Feng; Ma, Heng

    2016-05-01

    Insulin protects cardiomyocytes from myocardial ischemia/reperfusion (MI/R) injury through activating Akt. However, phosphatase PHLPP-1 (PH domain leucine-rich repeat protein phosphatase-1) dephosphorylates and inactivates Akt. The balanced competitive interaction of insulin and PHLPP-1 has not been directly examined. In this study, we have identified the effect of mutual inhibition of insulin signaling and PHLPP-1 on the cardioprotective efficiency of Akt in aged heart. Young (3 months) and aged (20 months) Sprague Dawley (SD) rats were subjected to MI/Rin vivo. The PHLPP-1 level was higher in aged vs. young hearts at base. But, insulin treatment failed to decrease PHLPP-1 level during reperfusion in the aged hearts. Consequently, the cardioprotection of insulin-induced Akt activation was impaired in aged hearts, resulting in more susceptible to MI/R injury. In cultured rat ventricular myocytes, PHLPP-1 knockdown significantly enhanced insulin-induced Akt phosphorylation and reduced simulated hypoxia/reoxygenation-induced apoptosis. Contrary, PHLPP-1 overexpression terminated Akt phosphorylation and deteriorated myocytes apoptosis. Using in vivo aged animal models, we confirmed that cardiac PHLPP-1 knockdown or enhanced insulin sensitivity by exercise training dramatically increased insulin-induced Akt phosphorylation. Specifically, MI/R-induced cardiomyocyte apoptosis and infarct size were decreased and cardiac function was increased. More importantly, we found that insulin regulated the degradation of PHLPP-1 and insulin treatment could enhance the binding between PHLPP-1 and β-transducin repeat-containing protein (β-TrCP) to target for ubiquitin-dependent degradation. Altogether, we have identified a new mechanism by which insulin suppresses PHLPP-1 to enhance Akt activation. But, aged heart possesses lower insulin effectiveness and fails to decrease PHLPP-1 during MI/R, which subsequently limited Akt activity and cardioprotection. PHLPP-1 could be a

  1. Mutual inhibition of insulin signaling and PHLPP-1 determines cardioprotective efficiency of Akt in aged heart

    PubMed Central

    Xing, Yuan; Sun, Wanqing; Wang, Yishi; Gao, Feng; Ma, Heng

    2016-01-01

    Insulin protects cardiomyocytes from myocardial ischemia/reperfusion (MI/R) injury through activating Akt. However, phosphatase PHLPP-1 (PH domain leucine-rich repeat protein phosphatase-1) dephosphorylates and inactivates Akt. The balanced competitive interaction of insulin and PHLPP-1 has not been directly examined. In this study, we have identified the effect of mutual inhibition of insulin signaling and PHLPP-1 on the cardioprotective efficiency of Akt in aged heart. Young (3 mon) and aged (20 mon) Sprague Dawley (SD) rats were subjected to MI/R in vivo. The PHLPP-1 level was higher in aged vs. young hearts at base. But, insulin treatment failed to decrease PHLPP-1 level during reperfusion in the aged hearts. Consequently, the cardioprotection of insulin-induced Akt activation was impaired in aged hearts, resulting in more susceptible to MI/R injury. In cultured rat ventricular myocytes, PHLPP-1 knockdown significantly enhanced insulin-induced Akt phosphorylation and reduced simulated hypoxia/reoxygenation-induced apoptosis. Contrary, PHLPP-1 overexpression terminated Akt phosphorylation and deteriorated myocytes apoptosis. Using in vivo aged animal models, we confirmed that cardiac PHLPP-1 knockdown or enhanced insulin sensitivity by exercise training dramatically increased insulin-induced Akt phosphorylation. Specifically, MI/R-induced cardiomyocyte apoptosis and infarct size were decreased and cardiac function was increased. More importantly, we found that insulin regulated the degradation of PHLPP-1 and insulin treatment could enhance the binding between PHLPP-1 and β-transducin repeat-containing protein (β-TrCP) to target for ubiquitin-dependent degradation. Altogether, we have identified a new mechanism by which insulin suppresses PHLPP-1 to enhance Akt activation. But, aged heart possesses lower insulin effectiveness and fails to decrease PHLPP-1 during MI/R, which subsequently limited Akt activity and cardioprotection. PHLPP-1 could be a promising

  2. Metformin as a Tool to Target Aging.

    PubMed

    Barzilai, Nir; Crandall, Jill P; Kritchevsky, Stephen B; Espeland, Mark A

    2016-06-14

    Aging has been targeted by genetic and dietary manipulation and by drugs in order to increase lifespan and health span in numerous models. Metformin, which has demonstrated protective effects against several age-related diseases in humans, will be tested in the TAME (Targeting Aging with Metformin) trial, as the initial step in the development of increasingly effective next-generation drugs. PMID:27304507

  3. Metformin pharmacogenomics: current status and future directions.

    PubMed

    Pawlyk, Aaron C; Giacomini, Kathleen M; McKeon, Catherine; Shuldiner, Alan R; Florez, Jose C

    2014-08-01

    The incidence of type 2 diabetes (T2D) and its costs to the health care system continue to rise. Despite the availability of at least 10 drug classes for the treatment of T2D, metformin remains the most widely used first-line pharmacotherapy for its treatment; however, marked interindividual variability in response and few clinical or biomarker predictors of response reduce its optimal use. As clinical care moves toward precision medicine, a variety of broad discovery-based "omics" approaches will be required. Technical innovation, decreasing sequencing cost, and routine sample storage and processing has made pharmacogenomics the most widely applied discovery-based approach to date. This opens up the opportunity to understand the genetics underlying the interindividual variation in metformin responses in order for clinicians to prescribe specific treatments to given individuals for better efficacy and safety: metformin for those predicted to respond and alternative therapies for those predicted to be nonresponders or who are at increased risk for adverse side effects. Furthermore, understanding of the genetic determinants of metformin response may lead to the identification of novel targets and development of more effective agents for diabetes treatment. The goals of this workshop sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases were to review the state of research on metformin pharmacogenomics, discuss the scientific and clinical hurdles to furthering our knowledge of the variability in patient responses to metformin, and consider how to effectively use this increased understanding to improve patient outcomes. PMID:25060887

  4. Use of Metformin in Diseases of Aging

    PubMed Central

    Miles, John M.; Rule, Andrew D.; Borlaug, Barry A.

    2014-01-01

    Metformin is the most commonly prescribed medication for type 2 diabetes (T2DM) in the world. It has primacy in the treatment of this disease because of its safety record and also because of evidence for reduction in the risk of cardiovascular events. Evidence has accumulated indicating that metformin is safe in people with stage 3 chronic kidney disease (CKD-3). It is estimated that roughly one-quarter of people with CKD-3 and T2DM in the United States (well over 1 million) are ineligible for metformin treatment because of elevated serum creatinine levels. This could be overcome if a scheme, perhaps based on pharmacokinetic studies, could be developed to prescribe reduced doses of metformin in these individuals. There is also substantial evidence from epidemiological studies to indicate that metformin may not only be safe, but may actually benefit people with heart failure (HF). Prospective, randomized trials of the use of metformin in HF are needed to investigate this possibility. PMID:24752835

  5. Metformin inhibits inflammatory response via AMPK-PTEN pathway in vascular smooth muscle cells

    SciTech Connect

    Kim, Sun Ae; Choi, Hyoung Chul

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer PTEN was induced by metformin and inhibited by compound C and AMPK siRNA. Black-Right-Pointing-Pointer Metformin suppressed TNF-{alpha}-induced COX-2 and iNOS mRNA expression. Black-Right-Pointing-Pointer Compound C and bpv (pic) increased iNOS and COX-2 protein expression. Black-Right-Pointing-Pointer NF-{kappa}B activation was restored by inhibiting AMPK and PTEN. Black-Right-Pointing-Pointer AMPK and PTEN regulated TNF-{alpha}-induced ROS production in VSMCs. -- Abstract: Atherosclerosis is a chronic inflammation of the coronary arteries. Vascular smooth muscle cells (VSMCs) stimulated by cytokines and chemokines accelerate the inflammatory response and migrate to the injured endothelium during the progression of atherosclerosis. Activation of AMP activated protein kinase (AMPK), a key sensor maintaining metabolic homeostasis, suppresses the inflammatory response. However, how AMPK regulates the inflammatory response is poorly understood. To identify the mechanism of this response, we focused on phosphatase and tensin homolog (PTEN), which is a negative regulator of inflammation. We investigated that activation of AMPK-induced PTEN expression and suppression of the inflammatory response through the AMPK-PTEN pathway in VSMCs. We treated with the well-known AMPK activator metformin to induce PTEN expression. PTEN was induced by metformin (2 mM) and inhibited by compound C (10 {mu}M) and AMPK siRNA. Tumor necrosis factor-alpha (TNF-{alpha}) was used to induce inflammation. The inflammatory response was confirmed by cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) expression, and activation of nuclear factor (NF)-{kappa}B. Metformin suppressed COX-2 and iNOS mRNA and protein expression dose dependently. Treatment with compound C and bpv (pic) in the presence of metformin, iNOS and COX-2 protein expression increased. NF-{kappa}B activation decreased in response to metformin and was restored by inhibiting AMPK

  6. Solid Dose Form of Metformin with Ethyl Eicosapentaenoic Acid Does Not Improve Metformin Plasma Availability

    PubMed Central

    Burton, Jeffrey H.; Johnson, William D.; Greenway, Frank L.

    2016-01-01

    Background The purpose of the study was to investigate effects of ethyl eicosapentaenoic acid on pharmacokinetics of metformin. Pharmacokinetic profiles of metformin and ethyl eicosapentaenoic acid when delivered separately or together in solid dose form were investigated and compared to determine whether the solid dose resulted in an altered metforminpharmacokinetics when given with or without food. Methods A single-center, open-label, repeated dose study investigated the pharmacokinetic (PK) profile of metformin when administered in solid dose form with ethyl eicosapentaenoic acid compared to co-administration with icosapent ethyl, an ester of eicosapentaenoic acid and ethyl alcohol used to treat severe hypertriglyceridemia with metformin hydrochloride. Non-compartmental PK methods were used to compare area under the plasma concentration curve (AUC) and maximum plasma concentration (Cmax) between patients randomized to either the ester or separate medications group under both fasting and fed conditions. Results Using these two PK parameters, results showed that metformin availability was higher under fasting conditions when delivered separately from icosapent ethyl. There were no group differences in the fed condition. Conclusions The solid dose form of metformin and ethyl eicosapentaenoic acid did not improve the pharmacokinetics of metformin in terms of plasma availability, suggesting that little is to be gained over the separate administration of ethyl eicosapentaenoic acid and metformin hydrochloride. PMID:26893954

  7. Metformin Beyond Diabetes: Pleiotropic Benefits of Metformin in Attenuation of Atherosclerosis

    PubMed Central

    Forouzandeh, Farshad; Salazar, Gloria; Patrushev, Nikolay; Xiong, Shiqin; Hilenski, Lula; Fei, Baowei; Alexander, R. Wayne

    2014-01-01

    Background Clinical studies show that metformin attenuates all‐cause mortality and myocardial infarction compared with other medications for type 2 diabetes, even at similar glycemic levels. However, there is paucity of data in the euglycemic state on the vasculoprotective effects of metformin. The objectives of this study are to evaluate the effects of metformin on ameliorating atherosclerosis. Methods and Results Using ApoE−/− C57BL/6J mice, we found that metformin attenuates atherosclerosis and vascular senescence in mice fed a high‐fat diet and prevents the upregulation of angiotensin II type 1 receptor by a high‐fat diet in the aortas of mice. Thus, considering the known deleterious effects of angiotensin II mediated by angiotensin II type 1 receptor, the vascular benefits of metformin may be mediated, at least in part, by angiotensin II type 1 receptor downregulation. Moreover, we found that metformin can cause weight loss without hypoglycemia. We also found that metformin increases the antioxidant superoxide dismutase‐1. Conclusion Pleiotropic effects of metformin ameliorate atherosclerosis and vascular senescence. PMID:25527624

  8. Research progress of cardioprotective agents for prevention of anthracycline cardiotoxicity

    PubMed Central

    Zhang, Jing; Cui, Xiaohai; Yan, Yan; Li, Min; Yang, Ya; Wang, Jiansheng; Zhang, Jia

    2016-01-01

    Anthracyclines, including doxorubicin, epirubicin, daunorubicin and aclarubicin, are widely used as chemotherapeutic agents in the treatment of hematologic and solid tumor, including acute leukemia, lymphoma, breast cancer, gastric cancer, soft tissue sarcomas and ovarian cancer. In the cancer treatment, anthracyclines also can be combined with other chemotherapies and molecular-targeted drugs. The combination of anthracyclines with other therapies is usually the first-line treatment. Anthracyclines are effective and potent agents with a broad antitumor spectrum, but may cause adverse reactions, including hair loss, myelotoxicity, as well as cardiotoxicity. We used hematopoietic stimulating factors to control the myelotoxicity, such as G-CSF, EPO and TPO. However, the cardiotoxicity is the most serious side effect of anthracyclines. Clinical research and practical observations indicated that the cardiotoxicity of anthracyclines is commonly progressive and irreversible. Especially to those patients who have the first time use of anthracyclines, the damage is common. Therefore, early detection and prevention of anthracyclines induced cardiotoxicity are particularly important and has already aroused more attention in clinic. By literature review, we reviewed the research progress of cardioprotective agents for prevention of anthracycline cardiotoxicity. PMID:27508008

  9. Metformin increases antitumor activity of MEK inhibitors through GLI1 downregulation in LKB1 positive human NSCLC cancer cells

    PubMed Central

    Della Corte, Carminia Maria; Ciaramella, Vincenza; Mauro, Concetta Di; Castellone, Maria Domenica; Papaccio, Federica; Fasano, Morena; Sasso, Ferdinando Carlo; Martinelli, Erika; Troiani, Teresa; De Vita, Ferdinando; Orditura, Michele; Bianco, Roberto; Ciardiello, Fortunato; Morgillo, Floriana

    2016-01-01

    Purpose Metformin, widely used as antidiabetic drug, showed antitumoral effects expecially in combination with chemotherapy. Our group recently has demonstrated that metformin and gefitinib are synergistic in LKB1-wild-type NSCLC cells. In these models, metformin as single agent induced an activation and phosphorylation of mitogen-activated-protein-kinase (MAPK) through an increased C-RAF/B-RAF heterodimerization. Experimental design Since single agent metformin enhances proliferating signals through the RAS/RAF/MAPK pathway, and several MEK inhibitors (MEK-I) demonstrated clinical efficacy in combination with other agents in NSCLC, we tested the effects of metformin plus MEK-I (selumetinib or pimasertib) on proliferation, invasiveness, migration abilities in vitro and in vivo in LKB1 positive NSCLC models harboring KRAS wild type and mutated gene. Results The combination of metformin with MEK-I showed a strong anti-proliferative and proapoptotic effect in Calu-3, H1299, H358 and H1975 human NSCLC cell lines, independently from the KRAS mutational status. The combination reduced the metastatic behaviour of NSCLC cells, via a downregulation of GLI1 trascritional activity, thus affecting the transition from an epithelial to a mesenchymal phenotype. Metformin and MEK-Is combinations also decreased the production and activity of MMP-2 and MMP-9 by reducing the NF-jB (p65) binding to MMP-2 and MMP-9 promoters. Conclusions Metformin potentiates the antitumor activity of MEK-Is in human LKB1-wild-type NSCLC cell lines, independently from the KRAS mutational status, through GLI1 downregulation and by reducing the NF-jB (p65)-mediated transcription of MMP-2 and MMP-9. PMID:26673006

  10. Pharmacologic screens reveal metformin that suppresses GRP78-dependent autophagy to enhance the anti-myeloma effect of bortezomib

    PubMed Central

    Jagannathan, S; Abdel-Malek, M A Y; Malek, E; Vad, N; Latif, T; Anderson, K C; Driscoll, J J

    2015-01-01

    Although the therapeutic benefit of proteasome inhibition in multiple myeloma remains unchallenged, drug resistance inevitably emerges through mechanisms that remain elusive. Bortezomib provokes unwanted protein accumulation and the endoplasmic reticulum stress to activate the unfolded protein response (UPR) and autophagy as compensatory mechanisms that restore protein homeostasis. High-throughput screens to detect pharmacologics that modulated autophagy to enhance the anti-myeloma effect of bortezomib revealed metformin, a widely used antidiabetic agent with proven efficacy and limited adverse effects. Metformin co-treatment with bortezomib suppressed induction of the critical UPR effector glucose-regulated protein 78 (GRP78) to impair autophagosome formation and enhance apoptosis. Gene expression profiling of newly diagnosed myeloma patient tumors further correlated the hyperexpression of GRP78-encoding HSPA5 with reduced clinical response to bortezomib. The effect of bortezomib was enhanced with metformin co-treatment using myeloma patient tumor cells and the chemoresistant, stem cell-like side population that may contribute to disease recurrence. The relevance of the findings was confirmed in vivo as shown by metformin co-treatment with bortezomib that delayed the growth of myeloma xenotransplants. Taken together, our results suggest that metformin suppresses GRP78, a key driver of bortezomib-induced autophagy, and support the pharmacologic repositioning of metformin to enhance the anti-myeloma benefit of bortezomib. PMID:26108695

  11. Radiosensitization of metformin in pancreatic cancer cells via abrogating the G2 checkpoint and inhibiting DNA damage repair.

    PubMed

    Wang, Zheng; Lai, Song-Tao; Ma, Ning-Yi; Deng, Yun; Liu, Yong; Wei, Dong-Ping; Zhao, Jian-Dong; Jiang, Guo-Liang

    2015-12-01

    Recent evidences have demonstrated the potential of metformin as a novel agent for cancer prevention and treatment. Here, we investigated its ability of radiosensitization and the underlying mechanisms in human pancreatic cancer cells. In this study, we found that metformin at 5 mM concentration enhanced the radiosensitivity of MIA PaCa-2 and PANC-1 cells, with sensitization enhancement ratios of 1.39 and 1.27, respectively. Mechanistically, metformin caused abrogation of the G2 checkpoint and increase of mitotic catastrophe, associated with suppression of Wee1 kinase and in turn CDK1 Tyr15 phosphorylation. Furthermore, metformin inhibited both expression and irradiation-induced foci formation of Rad51, a key player in homologous recombination repair, ultimately leading to persistent DNA damage, as reflected by γ-H2AX and 53BP1 signaling. Finally, metformin-mediated AMPK/mTOR/p70S6K was identified as a possible upstream pathway controlling translational regulation of Wee1 and Rad51. Our data suggest that metformin radiosensitizes pancreatic cancer cells in vitro via abrogation of the G2 checkpoint and inhibition of DNA damage repair. However, the in vivo study is needed to further confirm the findings from the in vitro study. PMID:26304716

  12. Antihypertensive and cardioprotective effects of pumpkin seed oil.

    PubMed

    El-Mosallamy, Aliaa E M K; Sleem, Amany A; Abdel-Salam, Omar M E; Shaffie, Nermeen; Kenawy, Sanaa A

    2012-02-01

    Pumpkin seed oil is a natural product commonly used in folk medicine for treatment of prostatic hypertrophy. In the present study, the effects of treatment with pumpkin seed oil on hypertension induced by the nitric oxide synthase inhibitor N(ω)-nitro-L-arginine methyl ester hydrochloride (L-NAME) (50 mg /kg/day) in rats were studied and compared with those of the calcium channel blocker amlodipine. Pumpkin seed oil (40 or 100 mg/kg), amlodipine (0.9 mg/kg), or vehicle (control) was given once daily orally for 6 weeks. Arterial blood pressure (BP), heart rate, electrocardiogram (ECG) changes, levels of serum nitric oxide (NO) (the concentrations of nitrite/nitrate), plasma malondialdehyde (MDA), blood glutathione, and erythrocytic superoxide dismutase activity were measured. Histopathological examination of heart and aorta was conducted as well. L-NAME administration resulted in a significant increase in BP starting from the second week. Pumpkin seed oil or amlodipine treatment significantly reduced the elevation in BP by L-NAME and normalized the L-NAME-induced ECG changes-namely, prolongation of the RR interval, increased P wave duration, and ST elevation. Both treatments significantly decreased the elevated levels of MDA and reversed the decreased levels of NO metabolites to near normal values compared with the L-NAME-treated group. Amlodipine also significantly increased blood glutathione content compared with normal (but not L-NAME-treated) rats. Pumpkin seed oil as well as amlodipine treatment protected against pathological alterations in heart and aorta induced by L-NAME. In conclusion, this study has shown that pumpkin seed oil exhibits an antihypertensive and cardioprotective effects through a mechanism that may involve generation of NO. PMID:22082068

  13. Functionalized nanoparticles provide early cardioprotection after acute myocardial infarction.

    PubMed

    Chang, Ming-Yao; Yang, Yu-Jen; Chang, Chih-Han; Tang, Alan C L; Liao, Wei-Yin; Cheng, Fong-Yu; Yeh, Chen-Sheng; Lai, James J; Stayton, Patrick S; Hsieh, Patrick C H

    2013-09-10

    Recent developments in nanotechnology have created considerable potential toward diagnosis and cancer therapy. In contrast, the use of nanotechnology in tissue repair or regeneration remains largely unexplored. We hypothesized that intramyocardial injection of insulin-like growth factor (IGF)-1-complexed poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles (PLGA-IGF-1 NPs) increases IGF-1 retention, induces Akt phosphorylation, and provides early cardioprotection after acute myocardial infarction (MI). We synthesized 3 different sizes of PLGA particles (60 nm, 200 nm, and 1 μm) which were complexed with IGF-1 using electrostatic force to preserve the biological function of IGF-1. Afterward, we injected PLGA-IGF-1 NPs in the heart after MI directly. Compared with the other two larger particles, the 60 nm-sized PLGA-IGF-1 NPs carried more IGF-1 and induced more Akt phosphorylation in cultured cardiomyocytes. PLGA-IGF-1 NPs also prolonged Akt activation in cardiomyocytes up to 24h and prevented cardiomyocyte apoptosis induced by doxorubicin in a dose-dependent manner. In vivo, PLGA-IGF-1 NP treatment significantly retained more IGF-1 in the myocardium than the IGF-1 alone treatment at 2, 6, 8, and 24 h. Akt phosphorylation was detected in cardiomyocytes 24h post-MI only in hearts receiving PLGA-IGF-1 NP treatment, but not in hearts receiving injection of PBS, IGF-1 or PLGA NPs. Importantly, a single intramyocardial injection of PLGA-IGF-1 NPs was sufficient to prevent cardiomyocyte apoptosis (P<0.001), reduce infarct size (P<0.05), and improve left ventricle ejection fraction (P<0.01) 21 days after experimental MI in mice. Our results not only demonstrate the potential of nanoparticle-based technology as a new approach to treating MI, but also have significant implications for translation of this technology into clinical therapy for ischemic cardiovascular diseases. PMID:23665256

  14. Tissue kallikrein is required for the cardioprotective effect of cyclosporin A in myocardial ischemia in the mouse.

    PubMed

    Youcef, G; Belaidi, E; Waeckel, L; Fazal, L; Clemessy, M; Vincent, M P; Zadigue, G; Richer, C; Alhenc-Gelas, F; Ovize, M; Pizard, A

    2015-03-01

    Clinical and experimental studies suggest that pharmacological postconditioning with Cyclosporin A (CsA) reduces infarct size in cardiac ischemia and reperfusion. CsA interacts with Cyclophilin D (CypD) preventing opening of the mitochondrial permeability transition pore (mPTP). Tissue kallikrein (TK) and its products kinins are involved in cardioprotection in ischemia. CypD knockout mice are resistant to the cardioprotective effects of both CsA and kinins suggesting common mechanisms of action. Using TK gene knockout mice, we investigated whether the kallikrein-kinin system is involved in the cardioprotective effect of CsA. Homozygote and heterozygote TK deficient mice (TK(-/-), TK(+/-)) and wild type littermates (TK(+/+)) were subjected to cardiac ischemia-reperfusion with and without CsA postconditioning. CsA reduced infarct size in TK(+/+) mice but had no effect in TK(+/-) and TK(-/-) mice. Cardiac mitochondria isolated from TK(-/-) mice had indistinguishable basal oxidative phosphorylation and calcium retention capacity compared to TK(+/+) mice but were resistant to CsA inhibition of mPTP opening. TK activity was documented in mouse heart and rat cardiomyoblasts mitochondria. By proximity ligation assay TK was found in close proximity to the mitochondrial membrane proteins VDAC and Tom22, and CypD. Thus, partial or total deficiency in TK induces resistance to the infarct size reducing effect of CsA in cardiac ischemia in mice, suggesting that TK level is a critical factor for cardioprotection by CsA. TK is required for the mitochondrial action of CsA and may interact with CypD. Genetic variability in TK activity has been documented in man and may influence the cardioprotective effect of CsA. PMID:25623731

  15. HL271, a novel chemical compound derived from metformin, differs from metformin in its effects on the circadian clock and metabolism.

    PubMed

    Row, Hansang; Jeong, Jaekap; Cho, Sehyung; Kim, Sungwuk; Kim, Kyungjin

    2016-01-15

    Metformin is a treatment of choice for patients with type 2 diabetes. Its action involves the phosphorylation of 5'-adenosine monophosphate activated protein kinase (AMPK), leading to inhibition of liver gluconeogenesis. The effects of a novel chemical compound derived from metformin, HL271, on molecular and physiological actions involving AMPK and rhythmically-expressed circadian clock genes were investigated. HL271 potently activated AMPK in a dose-dependent manner, and produced shortening of the circadian period and enhanced degradation of the clock genes PER2 and CRY1. Although the molecular effects of HL271 resembled those of metformin, it produced different physiological effects in mice with diet-induced obesity. HL271 did not elicit glucose-lowering or insulin-sensitizing effects, possibly because of altered regulation of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1. This indicated that, although HL271 acted on circadian clock machinery through a similar molecular mechanism to metformin, it differed in its systemic effect on glucose and lipid metabolite regulations. PMID:26707879

  16. Increase in apoptosis by combination of metformin with silibinin in human colorectal cancer cells

    PubMed Central

    Tsai, Cheng-Chia; Chuang, Tang-Wei; Chen, Li-Jen; Niu, Ho-Shan; Chung, Kun-Ming; Cheng, Juei-Tang; Lin, Kao-Chang

    2015-01-01

    AIM: To investigate the effect of metformin on silibinin-induced apoptosis in human colorectal cancer (COLO 205) cells. METHODS: MTT assays were performed to quantify cell viability. Western blot assays were applied to identify the expression of signaling proteins. RESULTS: The combined treatment of COLO 205 cells with metformin and silibinin decreased cell survival at a dose insufficient to influence the non-malignant cells [Human colonic epithelial cells (HCoEpiC)]. Silibinin and metformin increased phosphatase and tensin homolog and 5’-adenosine monophosphate-activated protein kinase expression in COLO 205 cells and inhibited the phosphorylation of mammol/Lalian target of rapamycin. This combined treatment resulted in an increase in the expression of activated caspase 3 and apoptosis inducing factor, indicating apoptosis. CONCLUSION: The combined treatment of human colorectal cancer cells with silibinin and metformin may induce apoptosis at a dose that does not affect HCoEpiC. This finding reveals a potential therapeutic strategy for the treatment of colorectal cancer. PMID:25892866

  17. In vitro and in vivo anti-tumor effect of metformin as a novel therapeutic agent in human oral squamous cell carcinoma

    PubMed Central

    2012-01-01

    Background Metformin, which is widely used as an antidiabetic agent, has recently been reported to reduce cancer risk and improve prognosis in certain malignancies. However, the specific mechanisms underlying the effect of metformin on the development and progression of several cancers including oral squamous cell carcinoma (OSCC) remain unclear. In the present study, we investigated the effects of metformin on OSCC cells in vitro and in vivo. Methods OSCC cells treated with or without metformin were counted using a hemocytometer. The clonogenic ability of OSCC cells after metformin treatment was determined by colony formation assay. Cell cycle progression and apoptosis were assessed by flow cytometry, and the activation of related signaling pathways was examined by immunoblotting. The in vivo anti-tumor effect of metformin was examined using a xenograft mouse model. Immunohistochemistry and TUNEL staining were used to determine the expression of cyclin D1 and the presence of apoptotic cells in tumors from mice treated with or without metformin. Results Metformin inhibited proliferation in the OSCC cell lines CAL27, WSU-HN6 and SCC25 in a time- and dose-dependent manner, and significantly reduced the colony formation of OSCC cells in vitro. Metformin induced an apparent cell cycle arrest at the G0/G1 phase, which was accompanied by an obvious activation of the AMP kinase pathway and a strongly decreased activation of mammalian target of rapamycin and S6 kinase. Metformin treatment led to a remarkable decrease of cyclin D1, cyclin-dependent kinase (CDK) 4 and CDK6 protein levels and phosphorylation of retinoblastoma protein, but did not affect p21 or p27 protein expression in OSCC cells. In addition, metformin induced apoptosis in OSCC cells, significantly down-regulating the anti-apoptotic proteins Bcl-2 and Bcl-xL and up-regulating the pro-apoptotic protein Bax. Metformin also markedly reduced the expression of cyclin D1 and increased the numbers of apoptotic

  18. Toxicity and toxicokinetics of metformin in rats

    SciTech Connect

    Quaile, Michael P.; Melich, David H.; Jordan, Holly L.; Nold, James B.; Chism, Jack P.; Polli, Joseph W.; Smith, Glenn A.; Rhodes, Melissa C.

    2010-03-15

    Metformin is a first-line drug for the treatment of type 2 diabetes (T2D) and is often prescribed in combination with other drugs to control a patient's blood glucose level and achieve their HbA1c goal. New treatment options for T2D will likely include fixed dose combinations with metformin, which may require preclinical combination toxicology studies. To date, there are few published reports evaluating the toxicity of metformin alone to aid in the design of these studies. Therefore, to understand the toxicity of metformin alone, Crl:CD(SD) rats were administered metformin at 0, 200, 600, 900 or 1200 mg/kg/day by oral gavage for 13 weeks. Administration of >= 900 mg/kg/day resulted in moribundity/mortality and clinical signs of toxicity. Other adverse findings included increased incidence of minimal necrosis with minimal to slight inflammation of the parotid salivary gland for males given 1200 mg/kg/day, body weight loss and clinical signs in rats given >= 600 mg/kg/day. Metformin was also associated with evidence of minimal metabolic acidosis (increased serum lactate and beta-hydroxybutyric acid and decreased serum bicarbonate and urine pH) at doses >= 600 mg/kg/day. There were no significant sex differences in mean AUC{sub 0-24} or C{sub max} nor were there significant differences in mean AUC{sub 0-24} or C{sub max} following repeated dosing compared to a single dose. The no observable adverse effect level (NOAEL) was 200 mg/kg/day (mean AUC{sub 0-24} = 41.1 mug h/mL; mean C{sub max} = 10.3 mug/mL based on gender average week 13 values). These effects should be taken into consideration when assessing potential toxicities of metformin in fixed dose combinations.

  19. Metformin versus insulin for gestational diabetes mellitus: a meta-analysis.

    PubMed

    Zhao, Li-Ping; Sheng, Xiao-Yan; Zhou, Shuang; Yang, Ting; Ma, Ling-Yue; Zhou, Ying; Cui, Yi-Min

    2015-11-01

    The aim of the present meta-analysis was to determine the efficacy and safety of metformin for the treatment of women with gestational diabetes mellitus (GDM). We searched databases, including PubMed, Embase and the Cochrane Central Register of Controlled Trials, for randomized controlled trials (RCTs) comparing metformin and insulin treatments in women with GDM. We carried out statistical analyses using RevMan 2011 and used the Grading of Recommendations, Assessment, Development, and Evaluations profiler to rate the quality of evidence of the primary outcomes. We analysed eight studies involving 1592 subjects. Meta-analysis of the RCTs showed that metformin had statistically significant effects on pregnancy-induced hypertension [PIH; risk ratio (RR) 0.54; 95% confidence interval (CI) 0.31, 0.91]. However, its effects on neonatal hypoglycaemia (RR 0.80; 95% CI 0.62, 1.02), rate of large-for-gestational age infants (RR 0.77; 95% CI 0.55, 1.08), respiratory distress syndrome (RR 1.26; 95% CI 0.67, 2.37), phototherapy (RR 0.94; 95% CI 0.67, 1.31) and perinatal death (RR 1.01; 95% CI 0.11, 9.53) were not significant. Our analyses suggest that there is no clinically relevant difference in efficacy or safety between metformin and insulin; however, metformin may be a good choice for GDM because of the lower risk of PIH. The advantages of metformin in terms of glycaemic control, PIH incidence and gestational age at birth are unclear, and should be verified in further trials. PMID:25925501

  20. Cardiac Sirt1 mediates the cardioprotective effect of caloric restriction by suppressing local complement system activation after ischemia-reperfusion.

    PubMed

    Yamamoto, Tsunehisa; Tamaki, Kayoko; Shirakawa, Kohsuke; Ito, Kentaro; Yan, Xiaoxiang; Katsumata, Yoshinori; Anzai, Atsushi; Matsuhashi, Tomohiro; Endo, Jin; Inaba, Takaaki; Tsubota, Kazuo; Sano, Motoaki; Fukuda, Keiichi; Shinmura, Ken

    2016-04-15

    Caloric restriction (CR) confers cardioprotection against ischemia-reperfusion (I/R) injury. We previously found the essential roles of endothelial nitric oxide synthase in the development of CR-induced cardioprotection and Sirt1 activation during CR (Shinmura K, Tamaki K, Ito K, Yan X, Yamamoto T, Katsumata Y, Matsuhashi T, Sano M, Fukuda K, Suematsu M, Ishii I. Indispensable role of endothelial nitric oxide synthase in caloric restriction-induced cardioprotection against ischemia-reperfusion injury.Am J Physiol Heart Circ Physiol308: H894-H903, 2015). However, the exact mechanism by which Sirt1 in cardiomyocytes mediates the cardioprotective effect of CR remains undetermined. We subjected cardiomyocyte-specificSirt1knockout (CM-Sirt1(-/-)) mice and the corresponding control mice to either 3-mo ad libitum feeding or CR (-40%). Isolated perfused hearts were subjected to 25-min global ischemia, followed by 60-min reperfusion. The recovery of left ventricle function after I/R was improved, and total lactate dehydrogenase release into the perfusate during reperfusion was attenuated in the control mice treated with CR, but a similar cardioprotective effect of CR was not observed in the CM-Sirt1(-/-)mice. The expression levels of cardiac complement component 3 (C3) at baseline and the accumulation of C3 and its fragments in the ischemia-reperfused myocardium were attenuated by CR in the control mice, but not in the CM-Sirt1(-/-)mice. Resveratrol treatment also attenuated the expression levels of C3 protein in cultured neonatal rat ventricular cardiomyocytes. Moreover, the degree of myocardial I/R injury in conventionalC3knockout (C3(-/-)) mice treated with CR was similar to that in the ad libitum-fedC3(-/-)mice, although the expression levels of Sirt1 were enhanced by CR. These results demonstrate that cardiac Sirt1 plays an essential role in CR-induced cardioprotection against I/R injury by suppressing cardiac C3 expression. This is the first report suggesting that

  1. Early Discontinuation of Metformin in Individuals Treated with Inhibitors of Transporters of Metformin.

    PubMed

    Stage, Tore Bjerregaard; Lee, Moa P; Hallas, Jesper; Christensen, Mette Marie Hougaard; Brøsen, Kim; Christensen, Kaare; Gagne, Joshua J; Pottegård, Anton

    2016-06-01

    The aim of this study was to examine the risk of early discontinuation of metformin as a proxy for intolerance, associated with use of drugs known to inhibit transporters involved in metformin distribution. We analysed all incident users of metformin in Denmark between 2000 and 2012 (n = 132,221) and in a cohort of US patients (n = 296,903). Risk of early discontinuation of metformin was assessed using adjusted logistic regression for 28 drugs putatively inhibiting metformin transporters and four negative controls. Increased odds ratio of early discontinuation of metformin was only associated with codeine, an inhibitor of organic cation transporter 1 in both cohorts [adjusted odds ratio (OR) in Danish cohort (95% CI): 1.13 (1.02-1.26), adjusted OR in American cohort (95% CI): 1.32 (1.19-1.47)]. The remaining drugs were not associated with increased odds ratio of early discontinuation and, surprisingly, four drugs were associated with a decreased risk. These findings indicate that codeine use may be associated with risk of early discontinuation of metformin and could be used as a basis for further investigation. PMID:27128732

  2. Impact of Metformin on Male Reproduction.

    PubMed

    Ferreira, Carolina; Sousa, Mário; Rabaça, Ana; Oliveira, Pedro F; Alves, Marco G; Sá, Rosália

    2015-01-01

    Male infertility has been increasing over the last decades being nowadays a pressing health problem. Diabetes mellitus (DM) can contribute directly or indirectly to male infertility due to an abnormal spermatogenesis, which results in a decreased sperm quality. Type 2 Diabetes mellitus (T2DM) is responsible for the vast majority of DM cases, being frequently treated with oral antidiabetic drugs. Metformin is the most cost-effective therapy for the treatment of T2DM. This biguanide is an oral insulin-sensitizing agent capable of increasing insulin sensitivity and decreasing plasma fasting insulin levels. The main metabolic action of this drug occurs in the liver. However, it has been shown that metformin acts on a variety of organs including the male reproductive system. With the rising numbers of diabetic individuals among younger populations, there is an increase in the consumption of metformin in individuals of this age group. As a result, it is important to discuss the role of metformin in male fertility. This review presents the most recent data available from studies on the effects of metformin on male reproductive system. Together with the discussion of these effects, their significance to male fertility is also debated. PMID:26166607

  3. Diabetes mellitus and metformin in hepatocellular carcinoma

    PubMed Central

    Fujita, Koji; Iwama, Hisakazu; Miyoshi, Hisaaki; Tani, Joji; Oura, Kyoko; Tadokoro, Tomoko; Sakamoto, Teppei; Nomura, Takako; Morishita, Asahiro; Yoneyama, Hirohito; Masaki, Tsutomu

    2016-01-01

    Hepatocellular carcinoma (HCC) is the leading cause of cancer-related death worldwide. Diabetes mellitus, a risk factor for cancer, is also globally endemic. The clinical link between these two diseases has been the subject of investigation for a century, and diabetes mellitus has been established as a risk factor for HCC. Accordingly, metformin, a first-line oral anti-diabetic, was first proposed as a candidate anti-cancer agent in 2005 in a cohort study in Scotland. Several subsequent large cohort studies and randomized controlled trials have not demonstrated significant efficacy for metformin in suppressing HCC incidence and mortality in diabetic patients; however, two recent randomized controlled trials have reported positive data for the tumor-preventive potential of metformin in non-diabetic subjects. The search for biological links between cancer and diabetes has revealed intracellular pathways that are shared by cancer and diabetes. The signal transduction mechanisms by which metformin suppresses carcinogenesis in cell lines or xenograft tissues and improves chemoresistance in cancer stem cells have also been elucidated. This review addresses the clinical and biological links between HCC and diabetes mellitus and the anti-cancer activity of metformin in clinical studies and basic experiments. PMID:27468203

  4. Metformin in combination with 5-fluorouracil suppresses tumor growth by inhibiting the Warburg effect in human oral squamous cell carcinoma.

    PubMed

    Harada, Koji; Ferdous, Tarannum; Harada, Toyoko; Ueyama, Yoshiya

    2016-07-01

    Cancer cells show enhanced glucose consumption and lactate production even in the presence of abundant oxygen, a phenomenon known as the Warburg effect, which is related to tumor proliferation, progression and drug-resistance in cancers. Hypoxia-inducible factor-1 (HIF-1) and several members of Phosphatidylinositol-4, 5-bisphosphate 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway positively contribute to the Warburg effect, whereas AMP activated protein Kinase (AMPK) acts as a negative regulator. Targeting the regulator molecules of Warburg effect might be a useful strategy to effectively kill cancer cells. Metformin was reported to be effective against various cancers as it inhibits cell proliferation by activating AMPK, and inhibiting mTOR and HIF-1α. Several studies suggested the efficacy of metformin with 5-fluorouracil (5-FU) against esophageal and colon cancer. In this study, we evaluated the efficacy of metformin and 5-FU combined therapy against human oral squamous cell carcinoma (OSCC) in vitro and in vivo. MTT assay and TUNEL assay revealed that metformin (4 mg/ml) and 5-FU (2.5 µg/ml) combination treatment effectively inhibited cell growth and induced apoptosis in OSCC cell lines (HSC2, HSC3 and HSC4) compared to either agent alone. Lactate colorimetric assay detected decreased level of lactate in the supernatants of metformin and 5-FU treated cells compared to cells treated with metformin or 5-FU. Western blot analysis showed marked downregulation of HIF-1α and mTOR expression, and upregulation of AMPKα in cells treated with metformin and 5-FU combination treatment. Combination therapy with metformin (200 mg/kg, i.p.) and 5-FU (10 mg/kg, i.p.) for 4 weeks (5 days/week) effectively reduced HSC2 tumor growth (77.6%) compared to metformin (59.9%) or 5-FU (52%) alone in nude mice. These findings suggest that metformin and 5-FU combined therapy could exert strong antitumor effect against OSCC through the inhibition of

  5. The small chill: mild hypothermia for cardioprotection?

    PubMed

    Tissier, Renaud; Chenoune, Mourad; Ghaleh, Bijan; Cohen, Michael V; Downey, James M; Berdeaux, Alain

    2010-12-01

    Reducing the heart's temperature by 2-5°C is a potent cardioprotective treatment in animal models of coronary artery occlusion. The anti-infarct benefit depends upon the target temperature and the time at which cooling is instituted. Protection primarily results from cooling during the ischaemic period, whereas cooling during reperfusion or beyond offers little protection. In animal studies, protection is proportional to both the depth and duration of cooling. An optimal cooling protocol must appreciably shorten the normothermic ischaemic time to effectively salvage myocardium. Patients presenting with acute myocardial infarction could be candidates for mild hypothermia since the current door-to-balloon time is typically 90 min. But they would have to be cooled quickly shortly after their arrival. Several strategies have been proposed for ultra-fast cooling, but most like liquid ventilation and pericardial perfusion are too invasive. More feasible strategies might include cutaneous cooling, peritoneal lavage with cold solutions, and endovascular cooling with intravenous thermodes. This last option has been investigated clinically, but the results have been disappointing possibly because the devices lacked capacity to cool the patient quickly or cooling was not implemented soon enough. The mechanism of hypothermia's protection has been assumed to be energy conservation. However, whereas deep hypothermia clearly preserves ATP, mild hypothermia has only a modest effect on ATP depletion during ischaemia. Some evidence suggests that intracellular signalling pathways might be responsible for the protection. It is unknown how cooling could trigger these pathways, but, if true, then it might be possible to duplicate cooling's protection pharmacologically. PMID:20621922

  6. Metformin Ameliorates Podocyte Damage by Restoring Renal Tissue Podocalyxin Expression in Type 2 Diabetic Rats

    PubMed Central

    Zhai, Limin; Gu, Junfei; Yang, Di; Wang, Wei; Ye, Shandong

    2015-01-01

    Podocalyxin (PCX) is a signature molecule of the glomerular podocyte and of maintaining integrity of filtration function of glomerulus. The aim of this study was to observe the effect of different doses of metformin on renal tissue PCX expression in type 2 diabetic rats and clarify its protection on glomerular podocytes. Type 2 diabetic Sprague-Dawley (SD) rats in which diabetes was induced by high-fat diet/streptozotocin (HFD-STZ) were treated with different doses of metformin (150, 300, and 500 mg/kg per day, resp.) for 8 weeks. Various biochemical parameters, kidney histopathology, and renal tissue PCX expression levels were examined. In type 2 diabetic rats, severe hyperglycemia and hyperlipidemia were developed. Urinary albumin and PCX were markedly increased. Diabetes induced significant alterations in renal glomerular structure. In addition, protein and mRNA expression of renal tissue PCX were highly decreased. However, treatment of rats with different doses of metformin restored all these changes to a varying degree. These results suggested that metformin can ameliorate glomerular podocyte damage in type 2 diabetic rats, which may be partly associated with its role in restoring PCX expression and inhibiting urinary excretion of PCX with dose dependence. PMID:26075281

  7. Cardioprotective Effects of Tualang Honey: Amelioration of Cholesterol and Cardiac Enzymes Levels.

    PubMed

    Khalil, Md Ibrahim; Tanvir, E M; Afroz, Rizwana; Sulaiman, Siti Amrah; Gan, Siew Hua

    2015-01-01

    The present study was designed to investigate the cardioprotective effects of Malaysian Tualang honey against isoproterenol- (ISO-) induced myocardial infarction (MI) in rats by investigating changes in the levels of cardiac marker enzymes, cardiac troponin I (cTnI), triglycerides (TG), total cholesterol (TC), lipid peroxidation (LPO) products, and antioxidant defense system combined with histopathological examination. Male albino Wistar rats (n = 40) were pretreated orally with Tualang honey (3 g/kg/day) for 45 days. Subcutaneous injection of ISO (85 mg/kg in saline) for two consecutive days caused a significant increase in serum cardiac marker enzymes (creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), and aspartate transaminase (AST)), cTnI, serum TC, and TG levels. In addition, ISO-induced myocardial injury was confirmed by a significant increase in heart lipid peroxidation (LPO) products (TBARS) and a significant decrease in antioxidant enzymes (SOD, GPx, GRx, and GST). Pretreatment of ischemic rats with Tualang honey conferred significant protective effects on all of the investigated biochemical parameters. The biochemical findings were further confirmed by histopathological examination in both Tualang-honey-pretreated and ISO-treated hearts. The present study demonstrates that Tualang honey confers cardioprotective effects on ISO-induced oxidative stress by contributing to endogenous antioxidant enzyme activity via inhibition of lipid peroxidation. PMID:26064893

  8. Cardioprotective Effects of Tualang Honey: Amelioration of Cholesterol and Cardiac Enzymes Levels

    PubMed Central

    Khalil, Md. Ibrahim; Tanvir, E. M.; Sulaiman, Siti Amrah; Gan, Siew Hua

    2015-01-01

    The present study was designed to investigate the cardioprotective effects of Malaysian Tualang honey against isoproterenol- (ISO-) induced myocardial infarction (MI) in rats by investigating changes in the levels of cardiac marker enzymes, cardiac troponin I (cTnI), triglycerides (TG), total cholesterol (TC), lipid peroxidation (LPO) products, and antioxidant defense system combined with histopathological examination. Male albino Wistar rats (n = 40) were pretreated orally with Tualang honey (3 g/kg/day) for 45 days. Subcutaneous injection of ISO (85 mg/kg in saline) for two consecutive days caused a significant increase in serum cardiac marker enzymes (creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), and aspartate transaminase (AST)), cTnI, serum TC, and TG levels. In addition, ISO-induced myocardial injury was confirmed by a significant increase in heart lipid peroxidation (LPO) products (TBARS) and a significant decrease in antioxidant enzymes (SOD, GPx, GRx, and GST). Pretreatment of ischemic rats with Tualang honey conferred significant protective effects on all of the investigated biochemical parameters. The biochemical findings were further confirmed by histopathological examination in both Tualang-honey-pretreated and ISO-treated hearts. The present study demonstrates that Tualang honey confers cardioprotective effects on ISO-induced oxidative stress by contributing to endogenous antioxidant enzyme activity via inhibition of lipid peroxidation. PMID:26064893

  9. Anthracycline-Induced Cardiomyopathy in Adults.

    PubMed

    Tan, Timothy C; Neilan, Tomas G; Francis, Sanjeev; Plana, Juan Carlos; Scherrer-Crosbie, Marielle

    2015-07-01

    Anthracyclines are one of the most commonly used antineoplastic agent classes, and a core part of the treatment in breast cancers, hematological malignancies, and sarcomas. Their benefit is decreased by their well-recognized cardiotoxicity. The purpose of this review is to outline the presentation, mechanisms, diagnosis, and treatment of anthracyclines-induced cardiotoxicity. Symptomatic heart failure occurs in 2% to 5% of patients treated with anthrayclines and may be higher in older patients or patients with cardiovascular risk factors. The mechanisms involved in anthracycline-induced cardiotoxicity involve myocyte loss by apoptosis in the presence of a limited regenerative capacity. Once symptomatic, anthracycline-induced cardiotoxicity is associated with markedly decreased survival. Left ventricular ejection fraction (LVEF), mostly determined using echocardiography, is used to monitor patients treated with anthracyclines. As more than 1/3 of patients treated with anthracyclines do not recover their baseline LVEF once it is decreased, more sensitive echocardiographic indices of LV function such as myocardial deformation or biomarkers have been studied in patients monitoring. Cardioprotective treatments such as angiotensin-converting enzyme inhibitors, beta-blockers, iron chelators, statins, and metformin are also the topic of research efforts. PMID:26140726

  10. Metformin Protects Kidney Cells From Insulin-Mediated Genotoxicity In Vitro and in Male Zucker Diabetic Fatty Rats.

    PubMed

    Othman, Eman Maher; Oli, R G; Arias-Loza, Paula-Anahi; Kreissl, Michael C; Stopper, Helga

    2016-02-01

    Hyperinsulinemia is thought to enhance cancer risk. A possible mechanism is induction of oxidative stress and DNA damage by insulin, Here, the effect of a combination of metformin with insulin was investigated in vitro and in vivo. The rationales for this were the reported antioxidative properties of metformin and the aim to gain further insights into the mechanisms responsible for protecting the genome from insulin-mediated oxidative stress and damage. The comet assay, a micronucleus frequency test, and a mammalian gene mutation assay were used to evaluate the DNA damage produced by insulin alone or in combination with metformin. For analysis of antioxidant activity, oxidative stress, and mitochondrial disturbances, the cell-free ferric reducing antioxidant power assay, the superoxide-sensitive dye dihydroethidium, and the mitochondrial membrane potential-sensitive dye 5,5',6,6'tetrachloro-1,1',3,3'-tetraethylbenzimidazol-carbocyanine iodide were applied. Accumulation of p53 and pAKT were analyzed. As an in vivo model, hyperinsulinemic Zucker diabetic fatty rats, additionally exposed to insulin during a hyperinsulinemic-euglycemic clamp, were treated with metformin. In the rat kidney samples, dihydroethidium staining, p53 and pAKT analysis, and quantification of the oxidized DNA base 8-oxo-7,8-dihydro-2'-deoxyguanosine were performed. Metformin did not show intrinsic antioxidant activity in the cell-free assay, but protected cultured cells from insulin-mediated oxidative stress, DNA damage, and mutation. Treatment of the rats with metformin protected their kidneys from oxidative stress and genomic damage induced by hyperinsulinemia. Metformin may protect patients from genomic damage induced by elevated insulin levels. This may support efforts to reduce the elevated cancer risk that is associated with hyperinsulinemia. PMID:26636185

  11. Metformin synergizes 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) combination therapy through impairing intracellular ATP production and DNA repair in breast cancer stem cells.

    PubMed

    Soo, Jaslyn Sian-Siu; Ng, Char-Hong; Tan, Si Hoey; Malik, Rozita Abdul; Teh, Yew-Ching; Tan, Boon-Shing; Ho, Gwo-Fuang; See, Mee-Hoong; Taib, Nur Aishah Mohd; Yip, Cheng-Har; Chung, Felicia Fei-Lei; Hii, Ling-Wei; Teo, Soo-Hwang; Leong, Chee-Onn

    2015-10-01

    Metformin, an AMPK activator, has been reported to improve pathological response to chemotherapy in diabetic breast cancer patients. To date, its mechanism of action in cancer, especially in cancer stem cells (CSCs) have not been fully elucidated. In this study, we demonstrated that metformin, but not other AMPK activators (e.g. AICAR and A-769662), synergizes 5-fluouracil, epirubicin, and cyclophosphamide (FEC) combination chemotherapy in non-stem breast cancer cells and breast cancer stem cells. We show that this occurs through an AMPK-dependent mechanism in parental breast cancer cell lines. In contrast, the synergistic effects of metformin and FEC occurred in an AMPK-independent mechanism in breast CSCs. Further analyses revealed that metformin accelerated glucose consumption and lactate production more severely in the breast CSCs but the production of intracellular ATP was severely hampered, leading to a severe energy crisis and impairs the ability of CSCs to repair FEC-induced DNA damage. Indeed, addition of extracellular ATP completely abrogated the synergistic effects of metformin on FEC sensitivity in breast CSCs. In conclusion, our results suggest that metformin synergizes FEC sensitivity through distinct mechanism in parental breast cancer cell lines and CSCs, thus providing further evidence for the clinical relevance of metformin for the treatment of cancers. PMID:26276035

  12. Triterpenoid saponins from Clematis tangutica and their cardioprotective activities.

    PubMed

    Zhang, Wei; Wang, Xiaoyang; Tang, Haifeng; Wang, Minchang; Ji, Lanju; Wen, Aidong; Wang, Jianbo

    2013-01-01

    Phytochemical investigation of the whole plants of Clematis tangutica led to the isolation of three new triterpenoid saponins (1-3), together with four known saponins (4-7). Their structures were determined by extensive spectral analysis and chemical evidences. Compounds 1-7 were evaluated for their cardioprotective activities in cardiomyocytes anoxia/reoxygenation (A/R) model. The results showed that those saponins exhibited cardioprotective effects by decreasing the levels of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH). PMID:23266737

  13. Cardioprotection from Ischemia-Reperfusion Injury by Near-Infrared Light in Rats

    PubMed Central

    Quirk, Brendan J.; Sonowal, Purabi; Jazayeri, Mohammad-Ali; Baker, John E.

    2014-01-01

    Abstract Objective: Myocardial reperfusion injury can induce further cardiomyocyte death and contribute to adverse cardiovascular outcomes after myocardial ischemia, cardiac surgery, or circulatory arrest. Exposure to near-infrared (NIR) light at the time of reoxygenation protects neonatal rat cardiomyocytes and HL-1 cells from injury. We hypothesized that application of NIR at 670 nm would protect the heart against ischemia-reperfusion injury. Methods: We assessed the protective role of NIR in in vivo and in vitro rat models of ischemia-reperfusion injury. Results: NIR application had no effect on the function of the nonischemic isolated heart, and had no effect on infarct size when applied during global ischemia. In the in vivo model, NIR commencing immediately before reperfusion decreased infarct size by 40%, 33%, 38%, and 77%, respectively, after regional ischemic periods of 30, 20, 15, and 10 min. Serum cardiac troponin I (cTnI) was significantly reduced in the 15 min group, whereas creatine kinase (CK) and lactate dehydrogenase (LDH) levels were not affected. Conclusions: We have demonstrated the safety of NIR application in an in vitro rat isolated model. In addition, we have demonstrated safety and efficacy when using NIR for cardioprotection in an in vivo rat ischemia model, and that this cardioprotection is dependent upon some factor present in blood, but not in perfusion buffer. Results show potential for cTnI, but not CK or LDH, as a biomarker for cardioprotection by NIR. NIR may have therapeutic utility in providing myocardial protection from ischemia-reperfusion injury. PMID:25093393

  14. Metformin inhibition of mTORC1 activation, DNA synthesis and proliferation in pancreatic cancer cells: Dependence on glucose concentration and role of AMPK

    SciTech Connect

    Sinnett-Smith, James; Kisfalvi, Krisztina; Kui, Robert; Rozengurt, Enrique

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer Metformin inhibits cancer cell growth but the mechanism(s) are not understood. Black-Right-Pointing-Pointer We show that the potency of metformin is sharply dependent on glucose in the medium. Black-Right-Pointing-Pointer AMPK activation was enhanced in cancer cells incubated in physiological glucose. Black-Right-Pointing-Pointer Reciprocally, metformin potently inhibited mTORC1, DNA synthesis and proliferation. Black-Right-Pointing-Pointer Metformin, at low concentrations, inhibited DNA synthesis through AMPK. -- Abstract: Metformin, a widely used anti-diabetic drug, is emerging as a potential anticancer agent but the mechanisms involved remain incompletely understood. Here, we demonstrate that the potency of metformin induced AMPK activation, as shown by the phosphorylation of its substrates acetyl-CoA carboxylase (ACC) at Ser{sup 79} and Raptor at Ser{sup 792}, was dramatically enhanced in human pancreatic ductal adenocarcinoma (PDAC) cells PANC-1 and MiaPaCa-2 cultured in medium containing physiological concentrations of glucose (5 mM), as compared with parallel cultures in medium with glucose at 25 mM. In physiological glucose, metformin inhibited mTORC1 activation, DNA synthesis and proliferation of PDAC cells stimulated by crosstalk between G protein-coupled receptors and insulin/IGF signaling systems, at concentrations (0.05-0.1 mM) that were 10-100-fold lower than those used in most previous reports. Using siRNA-mediated knockdown of the {alpha}{sub 1} and {alpha}{sub 2} catalytic subunits of AMPK, we demonstrated that metformin, at low concentrations, inhibited DNA synthesis through an AMPK-dependent mechanism. Our results emphasize the importance of using medium containing physiological concentrations of glucose to elucidate the anticancer mechanism of action of metformin in pancreatic cancer cells and other cancer cell types.

  15. Preventive effect of Metformin against N-nitrosodiethylamine-initiated hepatocellular carcinoma in rats

    PubMed Central

    Afzal, Muhammad; Kazmi, Imran; Gupta, Gaurav; Rahman, Mahfoozur; Kimothi, Vishwadeepak; Anwar, Firoz

    2012-01-01

    Effect of Metformin in chemically induced hepatocarcinogenesis was assessed in Wistar rats. Intraperitoneal administration of chemical carcinogen diethyl nitrosamine (DENA) (200 mg/kg) in single dose elevated the levels of serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), total cholesterol (TC), triglycerides (TG) and reduced high density lipoproteins (HDL), total proteins (TPR) and blood glucose level in tested animals. Histopathological examinations of the liver tissue showed marked carcinogenicity of the chemical carcinogen. Food and water intake, animal weights and serum albumin (ALB) were also assessed. The animals exposed to DENA showed a significant decrease in the body weights and, there were no significant alterations found in the total bilirubin (TBR) levels and gamma-glutamyltranspeptidase (GGTP), whereas the decreased levels of serum ALB were maintained by Metformin treatment. The elevated levels of serum SGOT, SGPT, ALP, AFP, TC and TG were restored by administration of Metformin in reduced dose (125 mg/kg) daily for 16 weeks p.o. Physiological and biochemical analysis showed the beneficial effects of Metformin in the animals exposed to DENA. PMID:23960811

  16. p21WAF1/CIP1 Expression is Differentially Regulated by Metformin and Rapamycin

    PubMed Central

    Molnar, Zoltan; Millward, Ann B.; Tse, Wai; Demaine, Andrew G.

    2014-01-01

    The mammalian target of rapamycin (mTOR) pathway plays an important role in the development of diabetic nephropathy and other age-related diseases. One of the features of DN is the elevated expression of p21WAF1/CIP1. However, the importance of the mTOR signalling pathway in p21 regulation is poorly understood. Here we investigated the effect of metformin and rapamycin on mTOR-related phenotypes in cell lines of epithelial origin. This study reports that metformin inhibits high glucose-induced p21 expression. High glucose opposed metformin in regulating cell size, proliferation, and protein synthesis. These effects were associated with reduced AMPK activation, affecting downstream mTOR signalling. However, the inhibition of the mTOR pathway by rapamycin did not have a negative effect on p21 expression, suggesting that metformin regulates p21 upstream of mTOR. These findings provide support for the hypothesis that AMPK activation may regulate p21 expression, which may have implications for diabetic nephropathy and other age-related pathologies. PMID:26464852

  17. The Role of Metformin in Metabolic Disturbances during Pregnancy: Polycystic Ovary Syndrome and Gestational Diabetes Mellitus

    PubMed Central

    Rojas, Joselyn; Chávez-Castillo, Mervin; Bermúdez, Valmore

    2014-01-01

    Maintenance of gestation implicates complex function of multiple endocrine mechanisms, and disruptions of the global metabolic environment prompt profound consequences on fetomaternal well-being during pregnancy and postpartum. Polycystic Ovary Syndrome (PCOS) and gestational diabetes mellitus (GDM) are very frequent conditions which increase risk for pregnancy complications, including early pregnancy loss, pregnancy-induced hypertensive disorders, and preterm labor, among many others. Insulin resistance (IR) plays a pivotal role in the pathogenesis of both PCOS and GDM, representing an important therapeutic target, with metformin being the most widely prescribed insulin-sensitizing antidiabetic drug. Although traditional views neglect use of oral antidiabetic agents during pregnancy, increasing evidence of safety during gestation has led to metformin now being recognized as a valuable tool in prevention of IR-related pregnancy complications and management of GDM. Metformin has been demonstrated to reduce rates of early pregnancy loss and onset of GDM in women with PCOS, and it appears to offer better metabolic control than insulin and other oral antidiabetic drugs during pregnancy. This review aims to summarize key aspects of current evidence concerning molecular and epidemiological knowledge on metformin use during pregnancy in the setting of PCOS and GDM. PMID:25763406

  18. Disentangling type 2 diabetes and metformin treatment signatures in the human gut microbiota.

    PubMed

    Forslund, Kristoffer; Hildebrand, Falk; Nielsen, Trine; Falony, Gwen; Le Chatelier, Emmanuelle; Sunagawa, Shinichi; Prifti, Edi; Vieira-Silva, Sara; Gudmundsdottir, Valborg; Krogh Pedersen, Helle; Arumugam, Manimozhiyan; Kristiansen, Karsten; Voigt, Anita Yvonne; Vestergaard, Henrik; Hercog, Rajna; Igor Costea, Paul; Kultima, Jens Roat; Li, Junhua; Jørgensen, Torben; Levenez, Florence; Dore, Joël; Nielsen, H Bjørn; Brunak, Søren; Raes, Jeroen; Hansen, Torben; Wang, Jun; Ehrlich, S Dusko; Bork, Peer; Pedersen, Oluf

    2015-12-10

    In recent years, several associations between common chronic human disorders and altered gut microbiome composition and function have been reported. In most of these reports, treatment regimens were not controlled for and conclusions could thus be confounded by the effects of various drugs on the microbiota, which may obscure microbial causes, protective factors or diagnostically relevant signals. Our study addresses disease and drug signatures in the human gut microbiome of type 2 diabetes mellitus (T2D). Two previous quantitative gut metagenomics studies of T2D patients that were unstratified for treatment yielded divergent conclusions regarding its associated gut microbial dysbiosis. Here we show, using 784 available human gut metagenomes, how antidiabetic medication confounds these results, and analyse in detail the effects of the most widely used antidiabetic drug metformin. We provide support for microbial mediation of the therapeutic effects of metformin through short-chain fatty acid production, as well as for potential microbiota-mediated mechanisms behind known intestinal adverse effects in the form of a relative increase in abundance of Escherichia species. Controlling for metformin treatment, we report a unified signature of gut microbiome shifts in T2D with a depletion of butyrate-producing taxa. These in turn cause functional microbiome shifts, in part alleviated by metformin-induced changes. Overall, the present study emphasizes the need to disentangle gut microbiota signatures of specific human diseases from those of medication. PMID:26633628

  19. Artocarpus heterophyllus L. seed starch-blended gellan gum mucoadhesive beads of metformin HCl.

    PubMed

    Nayak, Amit Kumar; Pal, Dilipkumar; Santra, Kousik

    2014-04-01

    Jackfruit (Artocarpus heterophyllus Lam., family: Moraceae) seed starch (JFSS)-gellan gum (GG) mucoadhesive beads containing metformin HCl were developed through ionotropic gelation technique. The effect of GG to JFSS ratio and CaCl2 concentration on the drug encapsulation efficiency (DEE, %) and cumulative drug release at 10h (R10h, %) was optimized and analyzed using response surface methodology based on 3(2) factorial design. The optimized JFSS-GG beads containing metformin HCl showed DEE of 92.67±4.46%, R10h of 61.30±2.37%, and mean diameter of 1.67±0.27 mm. The optimized beads showed pH-dependent swelling and mucoadhesivity with the goat intestinal mucosa. The in vitro drug release from all these JFSS-GG beads containing metformin HCl was followed zero-order pattern (R(2)=0.9907-0.9975) with super case-II transport mechanism over a period of 10 h. The beads were also characterized by SEM and FTIR. The optimized JFSS-GG beads containing metformin HCl exhibited significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. PMID:24447799

  20. Cardioprotective effects of inorganic nitrate/nitrite in chronic anthracycline cardiotoxicity: Comparison with dexrazoxane.

    PubMed

    Lenčová-Popelová, Olga; Jirkovský, Eduard; Jansová, Hana; Jirkovská-Vávrová, Anna; Vostatková-Tichotová, Lucie; Mazurová, Yvona; Adamcová, Michaela; Chládek, Jaroslav; Hroch, Miloš; Pokorná, Zuzana; Geršl, Vladimír; Šimůnek, Tomáš; Štěrba, Martin

    2016-02-01

    Dexrazoxane (DEX) is a clinically available cardioprotectant that reduces the toxicity induced by anthracycline (ANT) anticancer drugs; however, DEX is seldom used and its action is poorly understood. Inorganic nitrate/nitrite has shown promising results in myocardial ischemia-reperfusion injury and recently in acute high-dose ANT cardiotoxicity. However, the utility of this approach for overcoming clinically more relevant chronic forms of cardiotoxicity remains elusive. Hence, in this study, the protective potential of inorganic nitrate and nitrite against chronic ANT cardiotoxicity was investigated, and the results were compared to those using DEX. Chronic cardiotoxicity was induced in rabbits with daunorubicin (DAU). Sodium nitrate (1g/L) was administered daily in drinking water, while sodium nitrite (0.15 or 5mg/kg) or DEX (60mg/kg) was administered parenterally before each DAU dose. Although oral nitrate induced a marked increase in plasma NOx, it showed no improvement in DAU-induced mortality, myocardial damage or heart failure. Instead, the higher nitrite dose reduced the incidence of end-stage cardiotoxicity, prevented related premature deaths and significantly ameliorated several molecular and cellular perturbations induced by DAU, particularly those concerning mitochondria. The latter result was also confirmed in vitro. Nevertheless, inorganic nitrite failed to prevent DAU-induced cardiac dysfunction and molecular remodeling in vivo and failed to overcome the cytotoxicity of DAU to cardiomyocytes in vitro. In contrast, DEX completely prevented all of the investigated molecular, cellular and functional perturbations that were induced by DAU. Our data suggest that the difference in cardioprotective efficacy between DEX and inorganic nitrite may be related to their different abilities to address a recently proposed upstream target for ANT in the heart - topoisomerase IIβ. PMID:26724189

  1. Anti-cancer effect of metformin by suppressing signaling pathway of HER2 and HER3 in tamoxifen-resistant breast cancer cells.

    PubMed

    Kim, Jinkyoung; Lee, Jiyun; Kim, Chungyeul; Choi, Jinhyuk; Kim, Aeree

    2016-05-01

    Development of new therapeutic strategies is becoming increasingly important to overcome tamoxifen resistance. Recently, much interest has been focused on anti-tumor effects of metformin commonly used to treat type II diabetes. Increased protein expression and signaling of epidermal growth factor receptor (EGFR) family is a possible mechanism involved in tamoxifen resistance. Since HER2/HER3 heterodimers are able to induce strong downstream signaling and activate various biological responses such as cellular proliferation and growth, we investigated the anti-cancer effect of metformin by inhibition of signaling pathway via downregulation of HER2 and HER3 using tamoxifen-resistant MCF-7 (TR MCF-7) cells. Compared to MCF-7 cells, TR MCF-7 cells showed increased expression of EGFR, HER2, and HER3, and metformin inhibited the expression of these proteins in a dose- and time-dependent manner. Metformin inhibited activation of HER2 (Tyr1248)/HER3 (Tyr1289)/Akt (Ser473) as well as cell proliferation and colony formation by estrogenic promotion in MCF-7 and TR MCF-7 cells. Known as a HER3 ligand, heregulin (HRG)-β1-induced phosphorylation of HER2, HER3 and Akt, and protein interaction of HER2/HER3 and colony formation were inhibited by metformin in both cells. Consistent with the results in the two cell lines, we identified that metformin inhibited HER2/HER3/Akt signaling axis activated by HRG-β1 using the HER2 and HER3-overexpressing breast cancer cell line SK-BR-3. Lastly, lapatinib-induced HER3 upregulation was significantly inhibited by treatment of metformin in HER3 siRNA-transfected TR MCF-7 cells. These data suggest that metformin might overcome tamoxifen resistance through the inhibition of expression and signaling of receptor tyrosine kinase HER2 and HER3. PMID:26581908

  2. Metformin in gestational diabetes: An emerging contender

    PubMed Central

    Singh, Awadhesh Kumar; Singh, Ritu

    2015-01-01

    Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance occurring first time during pregnancy. Its prevalence is simultaneously increasing with the global rise of diabesity. GDM commonly develops, when maternal glucose metabolism is unable to compensate for the progressive development of insulin resistance, arising primarily from the consistently rising diabetogenic placental hormones. It classically develops during the second or third trimester. Theoretically, insulin sensitizers should have been the ideal agent in its treatment, given the insulin resistance, the major culprit in its pathogenesis. Fortunately, majority of women can be treated satisfactorily with lifestyle modification, and approximately 20% requires more intensive treatment. For several decades, insulin has been the most reliable treatment strategy and the gold standard in GDM. Metformin is effective insulin sensitizing agent and an established first line drug in type 2 diabetes currently. As it crosses the placenta, a safety issue remains an obstacle and, therefore, metformin is currently not recommended in the treatment of GDM. Nevertheless, given the emerging clinically equivalent safety and efficacy data of metformin compared to insulin, it appears that it may perhaps open a rather new door in managing GDM. The aim of this review is to critically analyze, the safety and efficacy data of metformin regarding its use in GDM and pregnant mothers with polycystic ovarian disease, which has emerged in past decades. PMID:25729685

  3. Metformin in Peritoneal Dialysis: A Pilot Experience

    PubMed Central

    Al-Hwiesh, Abdulla Khalaf; Abdul-Rahman, Ibrahiem Saeed; El-Deen, Mohammad Ahmad Nasr; Larbi, Emmanuel; Divino-Filho, Jose C.; Al-Mohanna, Fahd Abdul-Aziz; Gupta, Krishan L.

    2014-01-01

    ♦ Objective: In a number of patients, the antidiabetic drug metformin has been associated with lactic acidosis. Despite the fact that diabetes mellitus is the most common cause of end-stage renal disease (ESRD) and that peritoneal dialysis (PD) is an expanding modality of treatment, little is known about optimal treatment strategies in the large group of PD patients with diabetes. In patients with ESRD, the use of metformin has been limited because of the perceived risk of lactic acidosis or severe hypoglycemia. However, metformin use is likely to be beneficial, and PD might itself be a safeguard against the alleged complications. ♦ Methods: Our study involved 35 patients with insulin-dependent type 2 diabetes [median age: 54 years; interquartile range (IQR): 47-59 years] on automated PD (APD) therapy. Patients with additional risk factors for lactic acidosis were excluded. Metformin was introduced at a daily dose in the range 0.5 - 1.0 g. All patients were monitored for glycemic control by blood sugar levels and HbA1c. Plasma lactic acid levels were measured weekly for 4 weeks and then monthly to the end of the study. Plasma and effluent metformin and plasma lactate levels were measured simultaneously. ♦ Results: In this cohort, the median duration of diabetes was 18 years (IQR: 14 - 21 years), median time on PD was 31 months (IQR: 27 - 36 months), and median HbA1c was 6.8% (IQR: 5.9% - 6.9%). At metformin introduction and at the end of the study, the median anion gap was 11 mmol/L (IQR: 9 - 16 mmol/L) and 12 mmol/L (IQR: 9 - 16 mmol/L; p > 0.05) respectively, median pH was 7.33 (IQR: 7.32 - 7.36) and 7.34 (IQR: 7.32 - 7.36, p > 0.05) respectively, and mean metformin concentration in plasma and peritoneal fluid was 2.57 ± 1.49 mg/L and 2.83 ± 1.7 mg/L respectively. In the group overall, mean lactate was 1.39 ± 0.61 mmol/L, and hyperlactemia (>2 mmol/L to 5 mmol/L) was found in 4 of 525 plasma samples (0.76%), but the patients presented no symptoms. None

  4. Metformin combined with sodium dichloroacetate promotes B leukemic cell death by suppressing anti-apoptotic protein Mcl-1.

    PubMed

    Voltan, Rebecca; Rimondi, Erika; Melloni, Elisabetta; Gilli, Paola; Bertolasi, Valerio; Casciano, Fabio; Rigolin, Gian Matteo; Zauli, Giorgio; Secchiero, Paola

    2016-04-01

    Metformin and the mitochondrial targeting dichloroacetate (DCA) have recently received attention due to their ability to inhibit anaerobic glycolysis, which renders most cancer cells resistant to apoptosis induction. We observed that Metformin alone exhibited a dose-dependent anti-leukemic activity in both B leukemic cell lines and primary B-chronic lymphocytic leukemia (B-CLL) patients' cells and its anti-leukemic activity was enhanced when used in combination with DCA. In order to overcome the problems of poor bioavailability and cellular uptake, which limit DCA efficacy, we have designed and synthetized cocrystals consisting of Metformin and DCA (Met-DCA) at different stoichiometric ratios. Of note, the MetH(2)(++)•2DCA(-) cocrystal exhibited enhanced in vitro anti-leukemic activity, with respect to the treatment with the mix consisting of Metformin plus DCA. In particular, the treatment with the cocrystal MetH(2)(++)•2DCA(-) induced a synergistic apoptotic cell death coupled to a marked down-modulation of the anti-apoptotic Mcl-1 protein. Taken together, our data emphasize that innovative compounds based on Metformin-DCA combination merit to be further evaluated as chemotherapeutic agents for the treatment of B-CLL. PMID:26959881

  5. Variation in the glucose transporter gene SLC2A2 is associated with glycemic response to metformin

    PubMed Central

    Seiser, Eric L; van Leeuwen, Nienke; Tavendale, Roger; Bennett, Amanda J; Groves, Christopher J; Coleman, Ruth L; van der Heijden, Amber A; Beulens, Joline W; de Keyser, Catherine E; Zaharenko, Linda; Rotroff, Daniel M; Out, Mattijs; Jablonski, Kathleen A; Chen, Ling; Javorský, Martin; Židzik, Jozef; Levin, Albert M; Williams, L Keoki; Dujic, Tanja; Semiz, Sabina; Kubo, Michiaki; Chien, Huan-Chieh; Maeda, Shiro; Witte, John S; Wu, Longyang; Tkáč, Ivan; Kooy, Adriaan; van Schaik, Ron H N; Stehouwer, Coen D A; Logie, Lisa; Sutherland, Calum; Klovins, Janis; Pirags, Valdis; Hofman, Albert; Stricker, Bruno H; Motsinger-Reif, Alison A; Wagner, Michael J; Innocenti, Federico; 't Hart, Leen M; Holman, Rury R; McCarthy, Mark I; Hedderson, Monique M; Palmer, Colin N A; Florez, Jose C; Giacomini, Kathleen M; Pearson, Ewan R

    2016-01-01

    Metformin is the first-line antidiabetic drug with over 100 million users worldwide, yet its mechanism of action remains unclear1. Here the Metformin Genetics (MetGen) Consortium reports a three-stage genome-wide association study (GWAS), consisting of 13,123 participants of different ancestries. The C allele of rs8192675 in the intron of SLC2A2, which encodes the facilitated glucose transporter GLUT2, was associated with a 0.17% (p=6.6×10−14) greater metformin-induced in haemoglobin A1c (HbA1c) in 10,577 participants of European ancestry. rs8192675 is the top cis expression quantitative trait locus (cis-eQTL) for SLC2A2 in 1,226 human liver samples, suggesting a key role for hepatic GLUT2 in regulation of metformin action. Among obese individuals, C-allele homozygotes at rs8192675 had a 0.33% (3.6 mmol/mol) greater absolute HbA1c reduction than T-allele homozygotes. This was about half the effect seen with the addition of a DPP-4 inhibitor, and equated to a dose difference of 550mg of metformin, suggesting rs8192675 as a potential biomarker for stratified medicine. PMID:27500523

  6. Variation in the glucose transporter gene SLC2A2 is associated with glycemic response to metformin.

    PubMed

    Zhou, Kaixin; Yee, Sook Wah; Seiser, Eric L; van Leeuwen, Nienke; Tavendale, Roger; Bennett, Amanda J; Groves, Christopher J; Coleman, Ruth L; van der Heijden, Amber A; Beulens, Joline W; de Keyser, Catherine E; Zaharenko, Linda; Rotroff, Daniel M; Out, Mattijs; Jablonski, Kathleen A; Chen, Ling; Javorský, Martin; Židzik, Jozef; Levin, Albert M; Williams, L Keoki; Dujic, Tanja; Semiz, Sabina; Kubo, Michiaki; Chien, Huan-Chieh; Maeda, Shiro; Witte, John S; Wu, Longyang; Tkáč, Ivan; Kooy, Adriaan; van Schaik, Ron H N; Stehouwer, Coen D A; Logie, Lisa; Sutherland, Calum; Klovins, Janis; Pirags, Valdis; Hofman, Albert; Stricker, Bruno H; Motsinger-Reif, Alison A; Wagner, Michael J; Innocenti, Federico; Hart, Leen M 't; Holman, Rury R; McCarthy, Mark I; Hedderson, Monique M; Palmer, Colin N A; Florez, Jose C; Giacomini, Kathleen M; Pearson, Ewan R

    2016-09-01

    Metformin is the first-line antidiabetic drug with over 100 million users worldwide, yet its mechanism of action remains unclear. Here the Metformin Genetics (MetGen) Consortium reports a three-stage genome-wide association study (GWAS), consisting of 13,123 participants of different ancestries. The C allele of rs8192675 in the intron of SLC2A2, which encodes the facilitated glucose transporter GLUT2, was associated with a 0.17% (P = 6.6 × 10(-14)) greater metformin-induced reduction in hemoglobin A1c (HbA1c) in 10,577 participants of European ancestry. rs8192675 was the top cis expression quantitative trait locus (cis-eQTL) for SLC2A2 in 1,226 human liver samples, suggesting a key role for hepatic GLUT2 in regulation of metformin action. Among obese individuals, C-allele homozygotes at rs8192675 had a 0.33% (3.6 mmol/mol) greater absolute HbA1c reduction than T-allele homozygotes. This was about half the effect seen with the addition of a DPP-4 inhibitor, and equated to a dose difference of 550 mg of metformin, suggesting rs8192675 as a potential biomarker for stratified medicine. PMID:27500523

  7. Metformin combined with sodium dichloroacetate promotes B leukemic cell death by suppressing anti-apoptotic protein Mcl-1

    PubMed Central

    Melloni, Elisabetta; Gilli, Paola; Bertolasi, Valerio; Casciano, Fabio; Rigolin, Gian Matteo; Zauli, Giorgio; Secchiero, Paola

    2016-01-01

    Metformin and the mitochondrial targeting dichloroacetate (DCA) have recently received attention due to their ability to inhibit anaerobic glycolysis, which renders most cancer cells resistant to apoptosis induction. We observed that Metformin alone exhibited a dose-dependent anti-leukemic activity in both B leukemic cell lines and primary B-chronic lymphocytic leukemia (B-CLL) patients' cells and its anti-leukemic activity was enhanced when used in combination with DCA. In order to overcome the problems of poor bioavailability and cellular uptake, which limit DCA efficacy, we have designed and synthetized cocrystals consisting of Metformin and DCA (Met-DCA) at different stoichiometric ratios. Of note, the MetH2++•2DCA− cocrystal exhibited enhanced in vitro anti-leukemic activity, with respect to the treatment with the mix consisting of Metformin plus DCA. In particular, the treatment with the cocrystal MetH2++•2DCA− induced a synergistic apoptotic cell death coupled to a marked down-modulation of the anti-apoptotic Mcl-1 protein. Taken together, our data emphasize that innovative compounds based on Metformin-DCA combination merit to be further evaluated as chemotherapeutic agents for the treatment of B-CLL. PMID:26959881

  8. Disulfiram/copper-disulfiram Damages Multiple Protein Degradation and Turnover Pathways and Cytotoxicity is Enhanced by Metformin in Oesophageal Squamous Cell Carcinoma Cell Lines.

    PubMed

    Jivan, Rupal; Damelin, Leonard Howard; Birkhead, Monica; Rousseau, Amanda Louise; Veale, Robin Bruce; Mavri-Damelin, Demetra

    2015-10-01

    Disulfiram (DSF), used since the 1950s in the treatment of alcoholism, is reductively activated to diethyldithiocarbamate and both compounds are thiol-reactive and readily complex copper. More recently DSF and copper-DSF (Cu-DSF) have been found to exhibit potent anticancer activity. We have previously shown that the anti-diabetic drug metformin is anti-proliferative and induces an intracellular reducing environment in oesophageal squamous cell carcinoma (OSCC) cell lines. Based on these observations, we investigated the effects of Cu-DSF and DSF, with and without metformin, in this present study. We found that Cu-DSF and DSF caused considerable cytotoxicity across a panel of OSCC cells, and metformin significantly enhanced the effects of DSF. Elevated copper transport contributes to DSF and metformin-DSF-induced cytotoxicity since the cell-impermeable copper chelator, bathocuproinedisulfonic acid, partially reversed the cytotoxic effects of these drugs, and interestingly, metformin-treated OSCC cells contained higher intracellular copper levels. Furthermore, DSF may target cancer cells preferentially due to their high dependence on protein degradation/turnover pathways, and we found that metformin further enhances the role of DSF as a proteasome inhibitor. We hypothesized that the lysosome could be an additional, novel, target of DSF. Indeed, this acid-labile compound decreased lysosomal acidification, and DSF-metformin co-treatment interfered with the progression of autophagy in these cells. In summary, this is the first such report identifying the lysosome as a target of DSF and based on the considerable cytotoxic effects of DSF either alone or in the presence of metformin, in vitro, and we propose these as novel potential chemotherapeutic approaches for OSCC. PMID:25846272

  9. Prenatal Metformin Exposure in a Maternal High Fat Diet Mouse Model Alters the Transcriptome and Modifies the Metabolic Responses of the Offspring

    PubMed Central

    Salomäki, Henriikka; Heinäniemi, Merja; Vähätalo, Laura H.; Ailanen, Liisa; Eerola, Kim; Ruohonen, Suvi T.; Pesonen, Ullamari; Koulu, Markku

    2014-01-01

    Aims Despite the wide use of metformin in metabolically challenged pregnancies, the long-term effects on the metabolism of the offspring are not known. We studied the long-term effects of prenatal metformin exposure during metabolically challenged pregnancy in mice. Materials and Methods Female mice were on a high fat diet (HFD) prior to and during the gestation. Metformin was administered during gestation from E0.5 to E17.5. Male and female offspring were weaned to a regular diet (RD) and subjected to HFD at adulthood (10-11 weeks). Body weight and several metabolic parameters (e.g. body composition and glucose tolerance) were measured during the study. Microarray and subsequent pathway analyses on the liver and subcutaneous adipose tissue of the male offspring were performed at postnatal day 4 in a separate experiment. Results Prenatal metformin exposure changed the offspring's response to HFD. Metformin exposed offspring gained less body weight and adipose tissue during the HFD phase. Additionally, prenatal metformin exposure prevented HFD-induced impairment in glucose tolerance. Microarray and annotation analyses revealed metformin-induced changes in several metabolic pathways from which electron transport chain (ETC) was prominently affected both in the neonatal liver and adipose tissue. Conclusion This study shows the beneficial effects of prenatal metformin exposure on the offspring's glucose tolerance and fat mass accumulation during HFD. The transcriptome data obtained at neonatal age indicates major effects on the genes involved in mitochondrial ATP production and adipocyte differentiation suggesting the mechanistic routes to improved metabolic phenotype at adulthood. PMID:25541979

  10. Cardioprotection by Klotho through downregulation of TRPC6 channels in the mouse heart

    PubMed Central

    Xie, Jian; Cha, Seung-Kuy; An, Sung-Wan; Kuro-o, Makoto; Birnbaumer, Lutz; Huang, Chou-Long

    2012-01-01

    Klotho is a membrane protein predominantly produced in the kidney that exerts some anti-ageing effects. Ageing is associated with an increased risk of heart failure; whether Klotho is cardioprotective is unknown. Here we show that Klotho-deficient mice have no baseline cardiac abnormalities but develop exaggerated pathological cardiac hypertrophy and remodeling in response to stress. Cardioprotection by Klotho in normal mice is mediated by downregulation of TRPC6 channels in the heart. We demonstrate that deletion of Trpc6 prevents stress-induced exaggerated cardiac remodeling in Klotho-deficient mice. Furthermore, mice with heart-specific overexpression of TRPC6 develop spontaneous cardiac hypertrophy and remodeling. Klotho overexpression ameliorates cardiac pathologies in these mice and improves their long-term survival. Soluble Klotho present in the systemic circulation inhibits TRPC6 currents in cardiomyocytes by blocking phosphoinositide-3-kinase-dependent exocytosis of TRPC6 channels. These results provide a new perspective on the pathogenesis of cardiomyopathies and open new avenues for treatment of the disease. PMID:23212367

  11. Cardioprotection: A Review of Current Practice in Global Ischemia and Future Translational Perspective

    PubMed Central

    Laufer, Günther; Szeto, Wilson Y.; Petzelbauer, Peter; Ehrlich, Marek

    2014-01-01

    The idea of protecting the heart from ischemic insult during heart surgery to allow elective cardiac arrest is as old as the idea of cardiac surgery itself. The current gold standard in clinical routine is a high potassium regimen added either to crystalloid or blood cardioplegic solutions inducing depolarized arrest. Ongoing patient demographic changes with increasingly older, comorbidly ill patients and increasing case complexity with increasingly structurally abnormal hearts as morphological correlate paired with evolutions in pediatric cardiac surgery allowing more complex procedures than ever before redefine requirements for cardioprotection. Many, in part adversarial, regimens to protect the myocardium from ischemic insults have entered clinical routine; however, functional recovery of the heart is still often impaired due to perfusion injury. Myocardial reperfusion damage is a key determinant of postoperative organ functional recovery, morbidity, and mortality in adult and pediatric patients. There is a discrepancy between what current protective strategies are capable of and what they are expected to do in a rapidly changing cardiac surgery community. An increased understanding of the molecular players of ischemia reperfusion injury offers potential seeds for new cardioprotective regimens and may further displace boundaries of what is technically feasible. PMID:25276778

  12. Protease-activated receptor 4 deficiency offers cardioprotection after acute ischemia reperfusion injury.

    PubMed

    Kolpakov, Mikhail A; Rafiq, Khadija; Guo, Xinji; Hooshdaran, Bahman; Wang, Tao; Vlasenko, Liudmila; Bashkirova, Yulia V; Zhang, Xiaoxiao; Chen, Xiongwen; Iftikhar, Sahar; Libonati, Joseph R; Kunapuli, Satya P; Sabri, Abdelkarim

    2016-01-01

    Protease-activated receptor (PAR)4 is a low affinity thrombin receptor with less understood function relative to PAR1. PAR4 is involved in platelet activation and hemostasis, but its specific actions on myocyte growth and cardiac function remain unknown. This study examined the role of PAR4 deficiency on cardioprotection after myocardial ischemia-reperfusion (IR) injury in mice. When challenged by in vivo or ex vivo IR, PAR4 knockout (KO) mice exhibited increased tolerance to injury, which was manifest as reduced infarct size and a more robust functional recovery compared to wild-type mice. PAR4 KO mice also showed reduced cardiomyocyte apoptosis and putative signaling shifts in survival pathways in response to IR. Inhibition of PAR4 expression in isolated cardiomyocytes by shRNA offered protection against thrombin and PAR4-agonist peptide-induced apoptosis, while overexpression of wild-type PAR4 significantly enhanced the susceptibility of cardiomyocytes to apoptosis, even under low thrombin concentrations. Further studies implicate Src- and epidermal growth factor receptor-dependent activation of JNK on the proapoptotic effect of PAR4 in cardiomyocytes. These findings reveal a pivotal role for PAR4 as a regulator of cardiomyocyte survival and point to PAR4 inhibition as a therapeutic target offering cardioprotection after acute IR injury. PMID:26643815

  13. Mediterranean diet and cardioprotection: the role of nitrite, polyunsaturated fatty acids and polyphenols

    PubMed Central

    Nadtochiy, Sergiy M.; Redman, Emily K.

    2010-01-01

    The continually increasing rate of myocardial infarction (MI) in the Western world at least partly can be explained by a poor diet lacking in green vegetables, fruits, and fish, and enriched in food that contains saturated fat. In contrast, a number of epidemiological studies provide strong evidence highlighting the cardioprotective benefits of the Mediterranean diet enriched in green vegetables, fruits, fish and grape wine. Regular consumption of these products leads to an accumulation of nitrate/nitrite/NO•, polyunsaturated fatty acids (PUFA), and polyphenolic compounds, such as resveratrol, in the human body. Studies have confirmed that these constituents are bioactive exogenous mediators, which induce strong protection against MI. The aim of this review is to provide a critical, in-depth analysis of the cardioprotective pathways mediated by nitrite/NO•, PUFA, and phenolic compounds of grape wines discovered in the recent years, including cross-talk between different mechanisms and compounds. Overall, these findings may facilitate the design and synthesis of novel therapeutic tools for the treatment of MI. PMID:21454053

  14. Deciphering Signaling Pathway Networks to Understand the Molecular Mechanisms of Metformin Action

    PubMed Central

    Sun, Jingchun; Zhao, Min; Jia, Peilin; Wang, Lily; Wu, Yonghui; Iverson, Carissa; Zhou, Yubo; Bowton, Erica; Roden, Dan M.; Denny, Joshua C.; Aldrich, Melinda C.; Xu, Hua; Zhao, Zhongming

    2015-01-01

    A drug exerts its effects typically through a signal transduction cascade, which is non-linear and involves intertwined networks of multiple signaling pathways. Construction of such a signaling pathway network (SPNetwork) can enable identification of novel drug targets and deep understanding of drug action. However, it is challenging to synopsize critical components of these interwoven pathways into one network. To tackle this issue, we developed a novel computational framework, the Drug-specific Signaling Pathway Network (DSPathNet). The DSPathNet amalgamates the prior drug knowledge and drug-induced gene expression via random walk algorithms. Using the drug metformin, we illustrated this framework and obtained one metformin-specific SPNetwork containing 477 nodes and 1,366 edges. To evaluate this network, we performed the gene set enrichment analysis using the disease genes of type 2 diabetes (T2D) and cancer, one T2D genome-wide association study (GWAS) dataset, three cancer GWAS datasets, and one GWAS dataset of cancer patients with T2D on metformin. The results showed that the metformin network was significantly enriched with disease genes for both T2D and cancer, and that the network also included genes that may be associated with metformin-associated cancer survival. Furthermore, from the metformin SPNetwork and common genes to T2D and cancer, we generated a subnetwork to highlight the molecule crosstalk between T2D and cancer. The follow-up network analyses and literature mining revealed that seven genes (CDKN1A, ESR1, MAX, MYC, PPARGC1A, SP1, and STK11) and one novel MYC-centered pathway with CDKN1A, SP1, and STK11 might play important roles in metformin’s antidiabetic and anticancer effects. Some results are supported by previous studies. In summary, our study 1) develops a novel framework to construct drug-specific signal transduction networks; 2) provides insights into the molecular mode of metformin; 3) serves a model for exploring signaling pathways

  15. MicroRNA profiles following metformin treatment in a mouse model of non-alcoholic steatohepatitis.

    PubMed

    Katsura, Akiko; Morishita, Asahiro; Iwama, Hisakazu; Tani, Joji; Sakamoto, Teppei; Tatsuta, Miwa; Toyota, Yuka; Fujita, Koji; Kato, Kiyohito; Maeda, Emiko; Nomura, Takako; Miyoshi, Hisaaki; Yoneyama, Hirohito; Himoto, Takashi; Fujiwara, Shintaro; Kobara, Hideki; Mori, Hirohito; Niki, Toshiro; Ono, Masafumi; Hirashima, Mitsuomi; Masaki, Tsutomu

    2015-04-01

    Non-alcoholic steatohepatitis (NASH) is one of the most common causes of chronic liver disease and is considered to be a causative factor of cryptogenic cirrhosis and hepatocellular carcinoma. microRNAs (miRNAs) are small non-coding RNAs that negatively regulate messenger RNA (mRNA). Recently, it was demonstrated that the aberrant expression of certain miRNAs plays a pivotal role in liver disease. The aim of the present study was to evaluate changes in miRNA profiles associated with metformin treatment in a NASH model. Eight-week-old male mice were fed a methionine- and choline-deficient (MCD) diet alone or with 0.08% metformin for 15 weeks. Metformin significantly downregulated the level of plasma transaminases and attenuated hepatic steatosis and liver fibrosis. The expression of miRNA-376a, miRNA‑127, miRNA-34a, miRNA-300 and miRNA-342-3p was enhanced among the 71 upregulated miRNAs, and the expression of miRNA-122, miRNA-194, miRNA-101b and miRNA-705 was decreased among 60 downregulated miRNAs in the liver of MCD-fed mice when compared with control mice. Of note, miRNA profiles were altered following treatment with metformin in MCD-fed mice. miRNA-376a, miRNA‑127, miRNA-34a, miRNA-300 and miRNA-342-3p were downregulated, but miRNA-122, miRNA-194, miRNA‑101b and miRNA-705 were significantly upregulated in MCD-fed mice treated with metformin. miRNA profiles were altered in MCD-fed mice and metformin attenuated this effect on miRNA expression. Therefore, miRNA profiles are a potential tool that may be utilized to clarify the mechanism behind the metformin-induced improvement of hepatic steatosis and liver fibrosis. Furthermore, identification of targetable miRNAs may be used as a novel therapy in human NASH. PMID:25672270

  16. MicroRNA profiles following metformin treatment in a mouse model of non-alcoholic steatohepatitis

    PubMed Central

    KATSURA, AKIKO; MORISHITA, ASAHIRO; IWAMA, HISAKAZU; TANI, JOJI; SAKAMOTO, TEPPEI; TATSUTA, MIWA; TOYOTA, YUKA; FUJITA, KOJI; KATO, KIYOHITO; MAEDA, EMIKO; NOMURA, TAKAKO; MIYOSHI, HISAAKI; YONEYAMA, HIROHITO; HIMOTO, TAKASHI; FUJIWARA, SHINTARO; KOBARA, HIDEKI; MORI, HIROHITO; NIKI, TOSHIRO; ONO, MASAFUMI; HIRASHIMA, MITSUOMI; MASAKI, TSUTOMU

    2015-01-01

    Non-alcoholic steatohepatitis (NASH) is one of the most common causes of chronic liver disease and is considered to be a causative factor of cryptogenic cirrhosis and hepatocellular carcinoma. microRNAs (miRNAs) are small non-coding RNAs that negatively regulate messenger RNA (mRNA). Recently, it was demonstrated that the aberrant expression of certain miRNAs plays a pivotal role in liver disease. The aim of the present study was to evaluate changes in miRNA profiles associated with metformin treatment in a NASH model. Eight-week-old male mice were fed a methionine- and choline-deficient (MCD) diet alone or with 0.08% metformin for 15 weeks. Metformin significantly downregulated the level of plasma transaminases and attenuated hepatic steatosis and liver fibrosis. The expression of miRNA-376a, miRNA-127, miRNA-34a, miRNA-300 and miRNA-342-3p was enhanced among the 71 upregulated miRNAs, and the expression of miRNA-122, miRNA-194, miRNA-101b and miRNA-705 was decreased among 60 downregulated miRNAs in the liver of MCD-fed mice when compared with control mice. Of note, miRNA profiles were altered following treatment with metformin in MCD-fed mice. miRNA-376a, miRNA-127, miRNA-34a, miRNA-300 and miRNA-342-3p were down-regulated, but miRNA-122, miRNA-194, miRNA-101b and miRNA-705 were significantly upregulated in MCD-fed mice treated with metformin. miRNA profiles were altered in MCD-fed mice and metformin attenuated this effect on miRNA expression. Therefore, miRNA profiles are a potential tool that may be utilized to clarify the mechanism behind the metformin-induced improvement of hepatic steatosis and liver fibrosis. Furthermore, identification of targetable miRNAs may be used as a novel therapy in human NASH. PMID:25672270

  17. Cardioprotection by H2S engages a cGMP-dependent protein kinase G/phospholamban pathway

    PubMed Central

    Bibli, Sofia-Iris; Andreadou, Ioanna; Chatzianastasiou, Athanasia; Tzimas, Christos; Sanoudou, Despina; Kranias, Evangelia; Brouckaert, Peter; Coletta, Ciro; Szabo, Csaba; Kremastinos, Dimitrios Th.; Iliodromitis, Efstathios K.; Papapetropoulos, Andreas

    2015-01-01

    Aims H2S is known to confer cardioprotection; however, the pathways mediating its effects in vivo remain incompletely understood. The purpose of the present study is to evaluate the contribution of cGMP-regulated pathways in the infarct-limiting effect of H2S in vivo. Methods and results Anaesthetized rabbits were subjected to myocardial ischaemia (I)/reperfusion (R), and infarct size was determined in control or H2S-exposed groups. The H2S donor sodium hydrosulfide (NaHS, an agent that generates H2S) increased cardiac cGMP and reduced the infarct size. The cGMP-dependent protein kinase (PKG)-I inhibitor DT2 abrogated the protective effect of NaHS, whereas the control peptide TAT or l-nitroarginine methyl ester (l-NAME) did not alter the effect of NaHS. Moreover, the KATP channel inhibitor, glibenclamide, partially reversed the effects of NaHS, whereas inhibition of mitochondrial KATP did not modify the NaHS response. NaHS enhanced phosphorylation of phospholamban (PLN), in a PKG-dependent manner. To further investigate the role of PLN in H2S-mediated cardioprotection, wild-type and PLN KO mice underwent I/R. NaHS did not exert cardioprotection in PLN KO mice. Unlike what was observed in rabbits, genetic or pharmacological inhibition of eNOS abolished the infarct-limiting effect of NaHS in mice. Conclusions Our findings demonstrate (i) that administration of NaHS induces cardioprotection via a cGMP/PKG/PLN pathway and (ii) contribution of nitric oxide to the H2S response is species-specific. PMID:25870184

  18. Suppression of tumor angiogenesis by metformin treatment via a mechanism linked to targeting of HER2/HIF-1α/VEGF secretion axis

    PubMed Central

    Wang, Yaochun; Tang, Shouching; Sun, Xin; Feng, Xuefei; Li, Yan; Bao, Gang; Li, Pingping; Mao, Xiaona; Wang, Maode; Liu, Peijun

    2015-01-01

    Anti-angiogenesis is currently considered as one of the major antitumor strategies for its protective effects against tumor emergency and later progression. The anti-diabetic drug metformin has been demonstrated to significantly inhibit tumor angiogenesis based on recent studies. However, the mechanism underlying this anti-angiogenic effect still remains an enigma. In this study, we investigated metformin-induced inhibitory effect on tumor angiogenesis in vitro and in vivo. Metformin pretreatment significantly suppressed tumor paracrine signaling-induced angiogenic promotion even in the presence of heregulin (HRG)-β1 (a co-activator of HER2) pretreatment of HER2+ tumor cells. Similar to that of AG825, a specific inhibitor of HER2 phosphorylation, metformin treatment decreased both total and phosphorylation (Tyr 1221/1222) levels of HER2 protein and significantly reduced microvessel density and the amount of Fitc-conjugated Dextran leaking outside the vessel. Furthermore, our results of VEGF-neutralizing and -rescuing tests showed that metformin markedly abrogated HER2 signaling-induced tumor angiogenesis by inhibiting VEGF secretion. Inhibition of HIF-1α signaling by using RNAi or YC-1, a specific inhibitor of HIF-1α synthesis, both completely diminished mRNA level of VEGF and greatly inhibited endothelial cell proliferation promoted by HER2+ tumor cell-conditioned medium in both the absence and presence of HRG-β1 pretreatment. Importantly, metformin treatment decreased the number of HIF-1α nucleus positive cells in 4T1 tumors, accompanied by decreased microvessel density. Our data thus provides novel insight into the mechanism underlying the metformin-induced inhibition of tumor angiogenesis and indicates possibilities of HIF-1α-VEGF signaling axis in mediating HER2-induced tumor angiogenesis. PMID:26625311

  19. Suppression of tumor angiogenesis by metformin treatment via a mechanism linked to targeting of HER2/HIF-1α/VEGF secretion axis.

    PubMed

    Wang, Jichang; Li, Guangyue; Wang, Yaochun; Tang, Shouching; Sun, Xin; Feng, Xuefei; Li, Yan; Bao, Gang; Li, Pingping; Mao, Xiaona; Wang, Maode; Liu, Peijun

    2015-12-29

    Anti-angiogenesis is currently considered as one of the major antitumor strategies for its protective effects against tumor emergency and later progression. The anti-diabetic drug metformin has been demonstrated to significantly inhibit tumor angiogenesis based on recent studies. However, the mechanism underlying this anti-angiogenic effect still remains an enigma. In this study, we investigated metformin-induced inhibitory effect on tumor angiogenesis in vitro and in vivo. Metformin pretreatment significantly suppressed tumor paracrine signaling-induced angiogenic promotion even in the presence of heregulin (HRG)-β1 (a co-activator of HER2) pretreatment of HER2+ tumor cells. Similar to that of AG825, a specific inhibitor of HER2 phosphorylation, metformin treatment decreased both total and phosphorylation (Tyr 1221/1222) levels of HER2 protein and significantly reduced microvessel density and the amount of Fitc-conjugated Dextran leaking outside the vessel. Furthermore, our results of VEGF-neutralizing and -rescuing tests showed that metformin markedly abrogated HER2 signaling-induced tumor angiogenesis by inhibiting VEGF secretion. Inhibition of HIF-1α signaling by using RNAi or YC-1, a specific inhibitor of HIF-1α synthesis, both completely diminished mRNA level of VEGF and greatly inhibited endothelial cell proliferation promoted by HER2+ tumor cell-conditioned medium in both the absence and presence of HRG-β1 pretreatment. Importantly, metformin treatment decreased the number of HIF-1α nucleus positive cells in 4T1 tumors, accompanied by decreased microvessel density. Our data thus provides novel insight into the mechanism underlying the metformin-induced inhibition of tumor angiogenesis and indicates possibilities of HIF-1α-VEGF signaling axis in mediating HER2-induced tumor angiogenesis. PMID:26625311

  20. Population pharmacokinetic modeling and noncompartmental analysis demonstrated bioequivalence between metformin component of metformin/vildagliptin fixed-dose combination products and metformin immediate-release tablet sourced from various countries.

    PubMed

    Chitnis, Shripad D; Han, Yi; Yamaguchi, Masayuki; Mita, Sachiko; Zhao, Rong; Sunkara, Gangadhar; Kulmatycki, Kenneth

    2016-01-01

    Metformin is the first-line pharmacotherapy choice for treating type-2 diabetes mellitus, alone or in combination with other antidiabetic drugs. During the development of immediate-release (IR) metformin containing novel fixed-dose combination (FDC) products, several health-authorities require sponsors to demonstrate bioequivalence between FDC products and the country-sourced metformin for market approval. Eight bioequivalence studies that compared metformin/vildagliptin FDC product (test) to metformin IR tablet sourced from various countries (reference) were conducted. A population pharmacokinetic (PPK) analysis of pooled metformin concentration-time data was performed to evaluate whether country-sourced metformin is a significant covariate. The PPK analysis demonstrated that there was no clinically relevant effect of metformin source or race/ethnicity on metformin pharmacokinetics. Also, noncompartmental analysis conducted showed that 90%CI of geometric mean ratios of test to reference metformin formulations, calculated for maximum-concentration and exposure parameters, were within the 80%-125% criteria, indicating comparable metformin exposure regardless of the country-sourced metformin IR formulation. These results are consistent with the biopharmaceutics properties of metformin and provide scientific evidence that after assessing in vitro dissolution of novel FDC formulation, additional bioequivalence studies with multiple countries' reference products may not be required once bioequivalence is established with 1 country-sourced IR metformin formulation. PMID:27119577

  1. Prevention of tumor growth driven by PIK3CA and HPV oncogenes by targeting mTOR signaling with metformin in oral squamous carcinomas expressing OCT3

    PubMed Central

    Madera, Dmitri; Vitale-Cross, Lynn; Martin, Daniel; Schneider, Abraham; Molinolo, Alfredo A.; Gangane, Nitin; Carey, Thomas E.; McHugh, Jonathan B.; Komarck, Christine M.; Walline, Heather M.; William, William N.; Seethala, Raja R.; Ferris, Robert; Gutkind, J. Silvio

    2015-01-01

    Most head and neck squamous cell carcinomas (HNSCC) exhibit a persistent activation of the PI3K-mTOR signaling pathway. We have recently shown that metformin, an oral antidiabetic drug that is also used to treat lipodystrophy in HIV-infected (HIV+) individuals, diminishes mTOR activity and prevents the progression of chemically-induced experimental HNSCC premalignant lesions. Here, we explored the preclinical activity of metformin in HNSCCs harboring PIK3CA mutations and HPV oncogenes, both representing frequent HNSCC alterations, aimed at developing effective targeted preventive strategies. The biochemical and biological effects of metformin were evaluated in representative HNSCC cells expressing mutated PIK3CA or HPV oncogenes (HPV+). The oral delivery of metformin was optimized to achieve clinical relevant blood levels. Molecular determinants of metformin sensitivity were also investigated, and their expression levels examined in a large collection of HNSCC cases. We found that metformin inhibits mTOR signaling and tumor growth in HNSCC cells expressing mutated PIK3CA and HPV oncogenes, and that these activities require the expression of organic cation transporter 3 (OCT3/SLC22A3), a metformin uptake transporter. Co-expression of OCT3 and the mTOR pathway activation marker pS6 were observed in most HNSCC cases, including those arising in HIV+ patients. Activation of the PI3K-mTOR pathway is a widespread event in HNSCC, including HPV− and HPV+ lesions arising in HIV+ patients, all of which co-express OCT3. These observations may provide a rationale for the clinical evaluation of metformin to halt HNSCC development from precancerous lesions, including in HIV+ individuals at risk of developing HPV-associated cancers. PMID:25681087

  2. Prevention of tumor growth driven by PIK3CA and HPV oncogenes by targeting mTOR signaling with metformin in oral squamous carcinomas expressing OCT3.

    PubMed

    Madera, Dmitri; Vitale-Cross, Lynn; Martin, Daniel; Schneider, Abraham; Molinolo, Alfredo A; Gangane, Nitin; Carey, Thomas E; McHugh, Jonathan B; Komarck, Christine M; Walline, Heather M; William, William N; Seethala, Raja R; Ferris, Robert L; Gutkind, J Silvio

    2015-03-01

    Most squamous cell carcinomas of the head and neck (HNSCC) exhibit a persistent activation of the PI3K-mTOR signaling pathway. We have recently shown that metformin, an oral antidiabetic drug that is also used to treat lipodystrophy in HIV-infected (HIV(+)) individuals, diminishes mTOR activity and prevents the progression of chemically induced experimental HNSCC premalignant lesions. Here, we explored the preclinical activity of metformin in HNSCCs harboring PIK3CA mutations and HPV oncogenes, both representing frequent HNSCC alterations, aimed at developing effective targeted preventive strategies. The biochemical and biologic effects of metformin were evaluated in representative HNSCC cells expressing mutated PIK3CA or HPV oncogenes (HPV(+)). The oral delivery of metformin was optimized to achieve clinical relevant blood levels. Molecular determinants of metformin sensitivity were also investigated, and their expression levels were examined in a large collection of HNSCC cases. We found that metformin inhibits mTOR signaling and tumor growth in HNSCC cells expressing mutated PIK3CA and HPV oncogenes, and that these activities require the expression of organic cation transporter 3 (OCT3/SLC22A3), a metformin uptake transporter. Coexpression of OCT3 and the mTOR pathway activation marker pS6 were observed in most HNSCC cases, including those arising in HIV(+) patients. Activation of the PI3K-mTOR pathway is a widespread event in HNSCC, including HPV(-) and HPV(+) lesions arising in HIV(+) patients, all of which coexpress OCT3. These observations may provide a rationale for the clinical evaluation of metformin to halt HNSCC development from precancerous lesions, including in HIV(+) individuals at risk of developing HPV(-) associated cancers. PMID:25681087

  3. Metformin combined with aspirin significantly inhibit pancreatic cancer cell growth in vitro and in vivo by suppressing anti-apoptotic proteins Mcl-1 and Bcl-2

    PubMed Central

    Yue, Wen; Zheng, Xi; Lin, Yong; Yang, Chung S.; Xu, Qing; Carpizo, Darren; Huang, Huarong; DiPaola, Robert S.; Tan, Xiang-Lin

    2015-01-01

    Metformin and aspirin have been studied extensively as cancer preventive or therapeutic agents. However, the effects of their combination on pancreatic cancer cells have not been investigated. Herein, we evaluated the effects of metformin and aspirin, alone or in combination, on cell viability, migration, and apoptosis as well as the molecular changes in mTOR, STAT3 and apoptotic signaling pathways in PANC-1 and BxPC3 cells. Metformin and aspirin, at relatively low concentrations, demonstrated synergistically inhibitory effects on cell viability. Compared to the untreated control or individual drug, the combination of metformin and aspirin significantly inhibited cell migration and colony formation of both PANC-1 and BxPC-3 cells. Metformin combined with aspirin significantly inhibited the phosphorylation of mTOR and STAT3, and induced apoptosis as measured by caspase-3 and PARP cleavage. Remarkably, metformin combined with aspirin significantly downregulated the anti-apoptotic proteins Mcl-1 and Bcl-2, and upregulated the pro-apoptotic proteins Bim and Puma, as well as interrupted their interactions. The downregulation of Mcl-1 and Bcl-2 was independent of AMPK or STAT3 pathway but partially through mTOR signaling and proteasome degradation. In a PANC-1 xenograft mouse model, we demonstrated that the combination of metformin and aspirin significantly inhibited tumor growth and downregulated the protein expression of Mcl-1 and Bcl-2 in tumors. Taken together, the combination of metformin and aspirin significantly inhibited pancreatic cancer cell growth in vitro and in vivo by regulating the pro- and anti-apoptotic Bcl-2 family members, supporting the continued investigation of this two drug combination as chemopreventive or chemotherapeutic agents for pancreatic cancer. PMID:26056043

  4. Metabolomic fingerprint reveals that metformin impairs one-carbon metabolism in a manner similar to the antifolate class of chemotherapy drugs.

    PubMed

    Corominas-Faja, Bruna; Quirantes-Piné, Rosa; Oliveras-Ferraros, Cristina; Vazquez-Martin, Alejandro; Cufí, Sílvia; Martin-Castillo, Begoña; Micol, Vicente; Joven, Jorge; Segura-Carretero, Antonio; Menendez, Javier A

    2012-07-01

    Metabolomic fingerprint of breast cancer cells treated with the antidiabetic drug metformin revealed a significant accumulation of 5-formimino-tetrahydrofolate, one of the tetrahydrofolate forms carrying activated one-carbon units that are essential for the de novo synthesis of purines and pyrimidines. De novo synthesis of glutathione, a folate-dependent pathway interconnected with one-carbon metabolism was concomitantly depleted in response to metformin. End-product reversal studies demonstrated that thymidine alone leads to a significant but incomplete protection from metformin's cytostatic effects. The addition of the substrate hypoxanthine for the purine salvage pathway produces major rightward shifts in metformin's growth inhibition curves. Metformin treatment failed to activate the DNA repair protein ATM kinase and the metabolic tumor suppressor AMPK when thymidine and hypoxanthine were present in the extracellular milieu. Our current findings suggest for the first time that metformin can function as an antifolate chemotherapeutic agent that induces the ATM/AMPK tumor suppressor axis secondarily following the alteration of the carbon flow through the folate-related one-carbon metabolic pathways. PMID:22837425

  5. Metformin inhibits heme oxygenase-1 expression in cancer cells through inactivation of Raf-ERK-Nrf2 signaling and AMPK-independent pathways

    SciTech Connect

    Do, Minh Truong; Kim, Hyung Gyun; Khanal, Tilak; Choi, Jae Ho; Kim, Dong Hee; Jeong, Tae Cheon; Jeong, Hye Gwang

    2013-09-01

    Resistance to therapy is the major obstacle to more effective cancer treatment. Heme oxygenase-1 (HO-1) is often highly up-regulated in tumor tissues, and its expression is further increased in response to therapies. It has been suggested that inhibition of HO-1 expression is a potential therapeutic approach to sensitize tumors to chemotherapy and radiotherapy. In this study, we tested the hypothesis that the anti-tumor effects of metformin are mediated by suppression of HO-1 expression in cancer cells. Our results indicate that metformin strongly suppresses HO-1 mRNA and protein expression in human hepatic carcinoma HepG2, cervical cancer HeLa, and non-small-cell lung cancer A549 cells. Metformin also markedly reduced Nrf2 mRNA and protein levels in whole cell lysates and suppressed tert-butylhydroquinone (tBHQ)-induced Nrf2 protein stability and antioxidant response element (ARE)-luciferase activity in HepG2 cells. We also found that metformin regulation of Nrf2 expression is mediated by a Keap1-independent mechanism and that metformin significantly attenuated Raf-ERK signaling to suppress Nrf2 expression in cancer cells. Inhibition of Raf-ERK signaling by PD98059 decreased Nrf2 mRNA expression in HepG2 cells, confirming that the inhibition of Nrf2 expression is mediated by an attenuation of Raf-ERK signaling in cancer cells. The inactivation of AMPK by siRNA, DN-AMPK or the pharmacological AMPK inhibitor compound C, revealed that metformin reduced HO-1 expression in an AMPK-independent manner. These results highlight the Raf-ERK-Nrf2 axis as a new molecular target in anticancer therapy in response to metformin treatment. - Highlights: • Metformin inhibits HO-1 expression in cancer cells. • Metformin attenuates Raf-ERK-Nrf2 signaling. • Suppression of HO-1 by metformin is independent of AMPK. • HO-1 inhibition contributes to anti-proliferative effects of metformin.

  6. Metformin: A Hopeful Promise in Aging Research.

    PubMed

    Novelle, Marta G; Ali, Ahmed; Diéguez, Carlos; Bernier, Michel; de Cabo, Rafael

    2016-03-01

    Even though the inevitable process of aging by itself cannot be considered a disease, it is directly linked to life span and is the driving force behind all age-related diseases. It is an undisputable fact that age-associated diseases are among the leading causes of death in the world, primarily in industrialized countries. During the last several years, an intensive search of antiaging treatments has led to the discovery of a variety of drugs that promote health span and/or life extension. The biguanide compound metformin is widely used for treating people with type 2 diabetes and appears to show protection against cancer, inflammation, and age-related pathologies. Here, we summarize the recent developments about metformin use in translational aging research and discuss its role as a potential geroprotector. PMID:26931809

  7. Cardioprotective Effect of Beta-3 Adrenergic Receptor Agonism: Role of Neuronal Nitric Oxide Synthase

    PubMed Central

    Niu, Xiaolin; Watts, Vabren L.; Cingolani, Oscar H.; Sivakumaran, Vidhya; Leyton-Mange, Jordan S.; Ellis, Carla L.; Miller, Karen L.; Vandegaer, Konrad; Bedja, Djahida; Gabrielson, Kathleen L.; Paolocci, Nazareno; Kass, David A.; Barouch, Lili A.

    2012-01-01

    Objective The aim of this study is to determine if activation of β3-adrenoceptor (β3-AR) and downstream signaling of NOS isoforms protects the heart from failure and hypertrophy induced by pressure overload. Background β3-AR and its downstream signaling pathways are recognized as novel modulators of heart function. Unlike _1- and _2-ARs, _3-ARs are stimulated at high catecholamine concentrations and induce negative inotropic effects, serving as a “brake” to protect the heart from catecholamine overstimulation. Methods C57BL/6J and nNOS knock-out mice were assigned to receive transverse aortic constriction (TAC), BRL37344 (β3-agonist, BRL0.1 mg/kg/hour), or both. Results Three weeks of BRL treatment in wild type mice attenuated left ventricular dilation and systolic dysfunction, and partially reduced cardiac hypertrophy induced by TAC. This effect was associated with increased nitric oxide (NO) production and superoxide suppression. TAC decreased endothelial NO synthase (eNOS) dimerization, indicating eNOS uncoupling, which was not reversed by BRL treatment. However, nNOS protein expression was up-regulated 2-fold by BRL, and the suppressive effect of BRL on superoxide generation was abrogated by acute neuronal NO synthase (nNOS) inhibition. Furthermore, BRL cardioprotective effects were actually detrimental in nNOS−/− mice. Conclusion These results are the first to show in vivo cardioprotective effects of β3-AR specific agonism in pressure overload hypertrophy and heart failure, and support nNOS as the primary downstream NOS isoform in maintaining NO and reactive oxygen species (ROS) balance in the failing heart. PMID:22624839

  8. Modulation by metformin of molecular and histopathological alterations in the lung of cigarette smoke-exposed mice.

    PubMed

    Izzotti, Alberto; Balansky, Roumen; D'Agostini, Francesco; Longobardi, Mariagrazia; Cartiglia, Cristina; Micale, Rosanna T; La Maestra, Sebastiano; Camoirano, Anna; Ganchev, Gancho; Iltcheva, Marietta; Steele, Vernon E; De Flora, Silvio

    2014-06-01

    The anti-diabetic drug metformin is endowed with anti-cancer properties. Epidemiological and experimental studies, however, did not provide univocal results regarding its role in pulmonary carcinogenesis. We used Swiss H mice of both genders in order to detect early molecular alterations and tumors induced by mainstream cigarette smoke. Based on a subchronic toxicity study, oral metformin was used at a dose of 800 mg/kg diet, which is 3.2 times higher than the therapeutic dose in humans. Exposure of mice to smoke for 4 months, starting at birth, induced a systemic clastogenic damage, formation of DNA adducts, oxidative DNA damage, and extensive downregulation of microRNAs in lung after 10 weeks. Preneoplastic lesions were detectable after 7.5 months in both lung and urinary tract along with lung tumors, both benign and malignant. Modulation by metformin of 42 of 1281 pulmonary microRNAs in smoke-free mice highlighted a variety of mechanisms, including modulation of AMPK, stress response, inflammation, NFκB, Tlr9, Tgf, p53, cell cycle, apoptosis, antioxidant pathways, Ras, Myc, Dicer, angiogenesis, stem cell recruitment, and angiogenesis. In smoke-exposed mice, metformin considerably decreased DNA adduct levels and oxidative DNA damage, and normalized the expression of several microRNAs. It did not prevent smoke-induced lung tumors but inhibited preneoplastic lesions in both lung and kidney. In conclusion, metformin was able to protect the mouse lung from smoke-induced DNA and microRNA alterations and to inhibit preneoplastic lesions in lung and kidney but failed to prevent lung adenomas and malignant tumors induced by this complex mixture. PMID:24683044

  9. Modulation by metformin of molecular and histopathological alterations in the lung of cigarette smoke-exposed mice

    PubMed Central

    Izzotti, Alberto; Balansky, Roumen; D'Agostini, Francesco; Longobardi, Mariagrazia; Cartiglia, Cristina; Micale, Rosanna T; La Maestra, Sebastiano; Camoirano, Anna; Ganchev, Gancho; Iltcheva, Marietta; Steele, Vernon E; De Flora, Silvio

    2014-01-01

    The anti-diabetic drug metformin is endowed with anti-cancer properties. Epidemiological and experimental studies, however, did not provide univocal results regarding its role in pulmonary carcinogenesis. We used Swiss H mice of both genders in order to detect early molecular alterations and tumors induced by mainstream cigarette smoke. Based on a subchronic toxicity study, oral metformin was used at a dose of 800 mg/kg diet, which is 3.2 times higher than the therapeutic dose in humans. Exposure of mice to smoke for 4 months, starting at birth, induced a systemic clastogenic damage, formation of DNA adducts, oxidative DNA damage, and extensive downregulation of microRNAs in lung after 10 weeks. Preneoplastic lesions were detectable after 7.5 months in both lung and urinary tract along with lung tumors, both benign and malignant. Modulation by metformin of 42 of 1281 pulmonary microRNAs in smoke-free mice highlighted a variety of mechanisms, including modulation of AMPK, stress response, inflammation, NFκB, Tlr9, Tgf, p53, cell cycle, apoptosis, antioxidant pathways, Ras, Myc, Dicer, angiogenesis, stem cell recruitment, and angiogenesis. In smoke-exposed mice, metformin considerably decreased DNA adduct levels and oxidative DNA damage, and normalized the expression of several microRNAs. It did not prevent smoke-induced lung tumors but inhibited preneoplastic lesions in both lung and kidney. In conclusion, metformin was able to protect the mouse lung from smoke-induced DNA and microRNA alterations and to inhibit preneoplastic lesions in lung and kidney but failed to prevent lung adenomas and malignant tumors induced by this complex mixture. PMID:24683044

  10. Diabetes, pancreatic cancer, and metformin therapy.

    PubMed

    Gong, Jun; Robbins, Lori A; Lugea, Aurelia; Waldron, Richard T; Jeon, Christie Y; Pandol, Stephen J

    2014-01-01

    Pancreatic cancer carries a poor prognosis as most patients present with advanced disease and preferred chemotherapy regimens offer only modest effects on survival. Risk factors include smoking, obesity, heavy alcohol, and chronic pancreatitis. Pancreatic cancer has a complex relationship with diabetes, as diabetes can be both a risk factor for pancreatic cancer and a result of pancreatic cancer. Insulin, insulin-like growth factor-1 (IGF-1), and certain hormones play an important role in promoting neoplasia in diabetics. Metformin appears to reduce risk for pancreatic cancer and improve survival in diabetics with pancreatic cancer primarily by decreasing insulin/IGF signaling, disrupting mitochondrial respiration, and inhibiting the mammalian target of rapamycin (mTOR) pathway. Other potential anti-tumorigenic effects of metformin include the ability to downregulate specificity protein transcription factors and associated genes, alter microRNAs, decrease cancer stem cell proliferation, and reduce DNA damage and inflammation. Here, we review the most recent knowledge on risk factors and treatment of pancreatic cancer and the relationship between diabetes, pancreatic cancer, and metformin as a potential therapy. PMID:25426078

  11. Diabetes, pancreatic cancer, and metformin therapy

    PubMed Central

    Gong, Jun; Robbins, Lori A.; Lugea, Aurelia; Waldron, Richard T.; Jeon, Christie Y.; Pandol, Stephen J.

    2014-01-01

    Pancreatic cancer carries a poor prognosis as most patients present with advanced disease and preferred chemotherapy regimens offer only modest effects on survival. Risk factors include smoking, obesity, heavy alcohol, and chronic pancreatitis. Pancreatic cancer has a complex relationship with diabetes, as diabetes can be both a risk factor for pancreatic cancer and a result of pancreatic cancer. Insulin, insulin-like growth factor-1 (IGF-1), and certain hormones play an important role in promoting neoplasia in diabetics. Metformin appears to reduce risk for pancreatic cancer and improve survival in diabetics with pancreatic cancer primarily by decreasing insulin/IGF signaling, disrupting mitochondrial respiration, and inhibiting the mammalian target of rapamycin (mTOR) pathway. Other potential anti-tumorigenic effects of metformin include the ability to downregulate specificity protein transcription factors and associated genes, alter microRNAs, decrease cancer stem cell proliferation, and reduce DNA damage and inflammation. Here, we review the most recent knowledge on risk factors and treatment of pancreatic cancer and the relationship between diabetes, pancreatic cancer, and metformin as a potential therapy. PMID:25426078

  12. A novel description of FDG excretion in the renal system: application to metformin-treated models

    NASA Astrophysics Data System (ADS)

    Garbarino, S.; Caviglia, G.; Sambuceti, G.; Benvenuto, F.; Piana, M.

    2014-05-01

    This paper introduces a novel compartmental model describing the excretion of 18F-fluoro-deoxyglucose (FDG) in the renal system and a numerical method based on the maximum likelihood for its reduction. This approach accounts for variations in FDG concentration due to water re-absorption in renal tubules and the increase of the bladder’s volume during the FDG excretion process. From the computational viewpoint, the reconstruction of the tracer kinetic parameters is obtained by solving the maximum likelihood problem iteratively, using a non-stationary, steepest descent approach that explicitly accounts for the Poisson nature of nuclear medicine data. The reliability of the method is validated against two sets of synthetic data realized according to realistic conditions. Finally we applied this model to describe FDG excretion in the case of animal models treated with metformin. In particular we show that our approach allows the quantitative estimation of the reduction of FDG de-phosphorylation induced by metformin.

  13. Cardioprotection by 6-gingerol in diabetic rats.

    PubMed

    El-Bassossy, Hany M; Elberry, Ahmed A; Ghareib, Salah A; Azhar, Ahmad; Banjar, Zainy Mohammed; Watson, Malcolm L

    2016-09-01

    The current study was conducted to evaluate the effect of 6-gingerol (6G) on cardiac complications in streptozotocin (STZ)-induced diabetic (DM) rats. STZ-induced DM rats (single 50 mg/kg i.p. injection, 15 days prior to drug treatment) or time-matched controls were treated with 6G (75 mg/day route orally). After a further 8 weeks, blood was collected for biochemical analysis and 8-isoprostenol was measured in urine. Cardiac hemodynamics and ECG was assessed. 6G significantly attenuated the increased level of blood glucose in diabetic rats and improved cardiac hemodynamics in including RR interval, max dP/dt, min dP/dt and Tau. In addition, 6G alleviated the elevated ST segment, T amplitude and R amplitude with no significant effect on disturbed levels of adiponectin, TGF-β or 8-isoprostenol induced by diabetes. The results showed that treatment with 6G has an ameliorative effect on cardiac dysfunction induced by diabetes. Which may be not related to its potential antioxidant effect. PMID:27378426

  14. Aldehyde Dehydrogenase 2 Has Cardioprotective Effects on Myocardial Ischaemia/Reperfusion Injury via Suppressing Mitophagy

    PubMed Central

    Ji, Wenqing; Wei, Shujian; Hao, Panpan; Xing, Junhui; Yuan, Qiuhuan; Wang, Jiali; Xu, Feng; Chen, Yuguo

    2016-01-01

    Mitophagy, a selective form of autophagy, is excessively activated in myocardial ischemia/reperfusion (I/R). The study investigated whether aldehyde dehydrogenase 2 (ALDH2) exerted its cardioprotective effect by regulating mitophagy. Myocardial infarct size and apoptosis after I/R in rats were ameliorated by Alda-1, an ALDH2 activator, and aggravated by ALDH2 inhibition. Both in I/R rats and hypoxia/reoxygenation H9C2 cells, ALDH2 activation suppressed phosphatase and tensin homolog-induced putative kinase 1 (PINK1)/Parkin expression, regulating mitophagy, by preventing 4-hydroxynonenal, reactive oxygen species and mitochondrial superoxide accumulation. Furthermore, the effect was enhanced by ALDH2 inhibition. Thus, ALDH2 may protect hearts against I/R injury by suppressing PINK1/Parkin–dependent mitophagy. PMID:27148058

  15. Control of gluconeogenesis by metformin: does redox trump energy charge?

    PubMed

    Baur, Joseph A; Birnbaum, Morris J

    2014-08-01

    Metformin is the most widely prescribed drug to lower glucose in type II diabetics, yet its mechanism of action remains controversial. A new study reveals that metformin inhibits mitochondrial glycerol-3-phosphate dehydrogenase, triggering reduction of the cytosolic NADH/NAD(+) pool and impaired utilization of redox-dependent substrates for gluconeogenesis (Madiraju et al., 2014). PMID:25100057

  16. Pharmacokinetics, Safety, and Tolerability of Metformin in Healthy Elderly Subjects.

    PubMed

    Jang, Kyungho; Chung, Hyewon; Yoon, Jang-Soo; Moon, Seol-Joo; Yoon, Seo Hyun; Yu, Kyung-Sang; Kim, Kwangil; Chung, Jae-Yong

    2016-09-01

    Age-related physiological changes are known to alter the pharmacokinetics (PK) and pharmacodynamics (PD) of drugs. Metformin is commonly used as first-line medication for management of diabetes in elderly patients. However, the PK and PD of metformin have not been sufficiently studied in elderly subjects. Here, 12 elderly subjects, aged 65 to 85 years, and 20 younger healthy volunteers were orally administered 750 mg of metformin 2 hours after dinner, followed by administration of a second dose (500 mg) 12 hours later. An oral glucose tolerance test (OGTT) was performed 2 hours after the second dose, with 75 g of glucose administered. Blood samples were collected at specific time points after the second metformin dose for the assessment of PK and the glucose-lowering effect of metformin. Elderly subjects exhibited 1.7 and 2.0 times higher average Cmax and AUC∞ than the younger subjects, respectively (P = .007 and .001, respectively), and t1/2 was comparable between the elderly and younger subjects. However, relative glucose level changes from baseline after metformin administration tended to be lower in elderly subjects. Systemic exposure to metformin was elevated by 50% or more in elderly subjects, whereas the glucose-lowering effect was similar compared to younger subjects after 2 doses of metformin. PMID:26710683

  17. Dehydroepiandrosterone and metformin regulate proliferation of murine T lymphocytes

    PubMed Central

    Solano, M E; Sander, V; Wald, M R; Motta, A B

    2008-01-01

    The aim of the present study was to assess the effect of dehydroepiandrosterone (DHEA: 10 µM) and metformin (10 µM and 100 µM) in regulating proliferation of cultured T lymphocytes. T cells were isolated from lymph nodes of prepuberal BALB/c mice. We found that DHEA, metformin and DHEA + metformin added to the incubation media diminished proliferation of T cells. The inhibition by DHEA was higher than that produced by metformin, while the combined treatment showed a synergistic action that allowed us to speculate distinct regulatory pathways. This was supported later by other findings in which the addition of DHEA to the incubation media did not modify T lymphocyte viability, while treatment with metformin and DHEA + metformin diminished cellular viability and increased both early and late apoptosis. Moreover, DHEA diminished the content of the anti-oxidant molecule glutathione (GSH), whereas M and DHEA + metformin increased GSH levels and diminished lipid peroxidation. We conclude that DHEA and metformin diminish proliferation of T cells through different pathways and that not only the increase, but also the decrease of oxidative stress inhibited proliferation of T cells, i.e. a minimal status of oxidative stress, is necessary to trigger cellular response. PMID:18549441

  18. A labdane diterpene exerts ex vivo and in vivo cardioprotection against post-ischemic injury: involvement of AKT-dependent mechanisms.

    PubMed

    Cuadrado-Berrocal, Irene; Gómez-Gaviro, María V; Benito, Yolanda; Barrio, Alicia; Bermejo, Javier; Fernández-Santos, María Eugenia; Sánchez, Pedro L; Desco, Manuel; Fernández-Avilés, Francisco; Fernández-Velasco, María; Boscá, Lisardo; de Las Heras, Beatriz

    2015-02-15

    Therapeutic approaches to protect the heart from ischemia/reperfusion (I/R) injury are an area of intense research, as myocardial infarction is a major cause of mortality and morbidity. Diterpenes are bioactive natural products with great therapeutic potential. In the present study, we have investigated the in vivo cardioprotective effects of a labdane diterpene (DT1) against cardiac I/R injury and the molecular mechanisms involved. DT1 attenuates post-ischemic injury via an AKT-dependent activation of HIF-1α, survival pathways and inhibition of NF-κB signaling. Myocardial infarction (MI) was induced in Wistar rats occluding the left coronary artery (LCA) for 30min followed by 72h reperfusion. DT1 (5mg/kg) was intravenously administered at reperfusion. In addition, we investigated the mechanisms of cardioprotection in the Langendorff-perfused model. Cardioprotection was observed when DT1 was administered after myocardial injury. The molecular mechanisms involved the activation of the survival pathway PDK-1, AKT and AMPK, a reduced phosphorylation of PKD1/2 and sustained HIF-1α activity, leading to increased expression of anti-apoptotic proteins and decreased caspase-3 activation. Pharmacological inhibition of AKT following MI and prior to DT1 challenge significantly decreased the cardioprotection afforded by DT1 therapy at reperfusion. Cardiac function after MI was significantly improved after DT1-treatment, as evidenced by hemodynamic recovery and decreased myocardial infarct size. These findings demonstrate an efficient in vivo cardioprotection by diterpene DT1 against I/R when administered at reperfusion, opening new therapeutic strategies as adjunctive therapy for the pharmacological management of I/R injury. PMID:25557296

  19. The role of gasotransmitters NO, H2S and CO in myocardial ischaemia/reperfusion injury and cardioprotection by preconditioning, postconditioning and remote conditioning

    PubMed Central

    Andreadou, Ioanna; Iliodromitis, Efstathios K; Rassaf, Tienush; Schulz, Rainer; Papapetropoulos, Andreas; Ferdinandy, Péter

    2015-01-01

    Ischaemic heart disease is one of the leading causes of morbidity and mortality worldwide. The development of cardioprotective therapeutic agents remains a partly unmet need and a challenge for both medicine and industry, with significant financial and social implications. Protection of the myocardium can be achieved by mechanical vascular occlusions such as preconditioning (PC), when brief episodes of ischaemia/reperfusion (I/R) are experienced prior to ischaemia; postconditioning (PostC), when the brief episodes are experienced at the immediate onset of reperfusion; and remote conditioning (RC), when the brief episodes are experienced in another vascular territory. The elucidation of the signalling pathways, which underlie the protective effects of PC, PostC and RC, would be expected to reveal novel molecular targets for cardioprotection that could be modulated by pharmacological agents to prevent reperfusion injury. Gasotransmitters including NO, hydrogen sulphide (H2S) and carbon monoxide (CO) are a growing family of regulatory molecules that affect physiological and pathological functions. NO, H2S and CO share several common properties; they are beneficial at low concentrations but hazardous in higher amounts; they relax smooth muscle cells, inhibit apoptosis and exert anti-inflammatory effects. In the cardiovascular system, NO, H2S and CO induce vasorelaxation and promote cardioprotection. In this review article, we summarize current knowledge on the role of the gasotransmitters NO, H2S and CO in myocardial I/R injury and cardioprotection provided by conditioning strategies and highlight future perspectives in cardioprotection by NO, H2S, CO, as well as their donor molecules. Linked Articles This article is part of a themed section on Pharmacology of the Gasotransmitters. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-6 PMID:24923364

  20. Antiglycation and cell protective actions of metformin and glipizide in erythrocytes and monocytes.

    PubMed

    Adeshara, Krishna; Tupe, Rashmi

    2016-03-01

    Chronic hyperglycaemia causes glycation which subsequently results in the long-term complications of diabetes. Albumin, the major plasma protein is more sensitive to glycation resulting in structural, biological and physiological modifications. The long-term benefits of commonly used anti-diabetic drugs such as metformin and glipizide in diabetic patients are well understood. However, no extensive study has been performed to assess their role in the glycation induced albumin modifications and cellular protection. We carried out the glycation of bovine serum albumin using methylglyoxal as a glycating agent in absence or presence of metformin and glipizide to establish their anti-glycation action. Different glycation markers (fructosamine, carbonyl groups, free thiol groups and β-amyloid aggregation) and protein structural markers (absorption spectroscopy and native-polyacrylamide gel electrophoresis) were examined. Further THP-1 cells (monocytes) and erythrocytes were treated with drugs that were exposed to glycated albumin samples for 24 h, respectively at 37 °C to investigate the cytoprotective actions of drugs against glycation. After the treatment different anti-oxidant indices (catalase, glutathione, superoxide dismutase and nitric oxide), cell viability, lipid peroxidation and erythrocyte hemolysis were determined. Treatment with metformin and glipizide during in vitro albumin glycation significantly reduced the formation of glycation adducts and inhibited structural modifications. They restored the level of antioxidants in THP-1 and erythrocytes cells treated with glycated albumin thus protecting cells. Our results suggested protection mode of albumin glycation through inhibition by metformin and glipizide. Additionally, they exerted inhibitory actions on glycation-induced cellular damage by restoring cellular antioxidant defense. PMID:26874852

  1. [Advances of the anti-tumor research of metformin].

    PubMed

    Xue, Chao-jun; Liu, Ke-xin

    2015-10-01

    Metformin is the most commonly prescibed drug for type 2 diabetes mellitus as it is inexpensive, safe, and efficient in ameliorating hyperglycemia and hyperinsulinemia. Numerous epidemiological studies indicate that diabetic population is not only at increased risk of cardiovascular complications, but also at substantially higher risk of many forms of malignancies. Meanwhile, epidemiological and clinical observation studies have shown that metformin use reduces risk of cancer in patients with type 2 diabetes mellitus and improves prognosis and survival rate of the cancer patients. Furthermore, metformin has been used for cancer therapy in clinical trials. Thus, metformin is emerging as a new cancer therapy or adjuvant anticancer drugs. This review summarizes recent progress in studies of metformin use and its molecular mechanism. PMID:26837164

  2. Understanding the benefit of metformin use in cancer treatment

    PubMed Central

    2011-01-01

    Biguanides have been developed for the treatment of hyperglycemia and type 2 diabetes. Recently, metformin, the most widely prescribed biguanide, has emerged as a potential anticancer agent. Epidemiological, preclinical and clinical evidence supports the use of metformin as a cancer therapeutic. The ability of metformin to lower circulating insulin may be particularly important for the treatment of cancers known to be associated with hyperinsulinemia, such as those of the breast and colon. Moreover, metformin may exhibit direct inhibitory effects on cancer cells by inhibiting mammalian target of rapamycin (mTOR) signaling and protein synthesis. The evidence supporting a role for metformin in cancer therapy and its potential molecular mechanisms of action are discussed. PMID:21470407

  3. [Investigation of the antioxidant activity and cardioprotective effect of reamberin and cytoflavin in newborn rats exposed to chronic hemic hypoxia].

    PubMed

    Zadnipryanyi, I V; Tretyakova, O S; Sataeva, T P

    2015-01-01

    The authors analyzed the antioxidant activity of reamberin and cytoflavin and evaluated their cardioprotective effect, by investigating lipid peroxidation and oxidative modification of plasma proteins, as well as the ultrastructure of newborn rat cardiomyocytes under chronic hemic hypoxia induced by sodium nitrite. Reamberin and cytoflavin can reduce the manifestations of mitochondrial dysfunction and the degree of cardiomyocyte damage in the neonatal rats due to the antioxidant and membrane-protective properties of the drugs. Succinic acid in combination with the metabolic components of the drugs significantly inhibits lipid peroxidation, by improving the structure of membranes and the mitochondrial function of cardiomyocytes. PMID:26841648

  4. Antitumor effect of metformin in esophageal cancer: in vitro study.

    PubMed

    Kobayashi, Mitsuyoshi; Kato, Kiyohito; Iwama, Hisakazu; Fujihara, Shintaro; Nishiyama, Noriko; Mimura, Shima; Toyota, Yuka; Nomura, Takako; Nomura, Kei; Tani, Joji; Miyoshi, Hisaaki; Kobara, Hideki; Mori, Hirohito; Murao, Koji; Masaki, Tsutomu

    2013-02-01

    Recent studies suggest that metformin, which is a member of the biguanide family and commonly used as an oral anti-hyperglycemic agent, may reduce cancer risk and improve prognosis of numerous types of cancer. However, the mechanisms underlying the antitumor effect of metformin on esophageal cancer remain unknown. The goal of the present study was to evaluate the effects of metformin on the proliferation of human ESCC in vitro, and to study changes in the expression profile of microRNAs (miRNAs), since miRNAs have previously been associated with the antitumor effects of metformin in other human cancers. The human ESCC cell lines T.T, KYSE30 and KYSE70 were used to study the effects of metformin on human ESCC in vitro. In addition, we used miRNA array tips to explore the differences between miRNAs in KYSE30 cells with and without metformin treatment. Metformin inhibited the proliferation of T.T, KYSE30 and KYSE70 cells in vitro. Metformin blocked the cell cycle in G0/G1 in vitro. This blockade was accompanied by a strong decrease of G1 cyclins, especially cyclin D1, as well as decreases in cyclin-dependent kinase (Cdk)4, Cdk6 and phosphorylated retinoblastoma protein (Rb). In addition, the expression of miRNAs was markedly altered with the treatment of metformin in vitro. Metformin inhibited the growth of three ESCC cell lines, and this inhibition may have involved reductions in cyclin D1, Cdk4 and Cdk6. PMID:23229592

  5. Cardioprotective effects of Guanxinshutong (GXST) against myocardial ischemia/ reperfusion injury in rats

    PubMed Central

    Liang, Zhuo; Liu, Li-Feng; Yao, Tian-Ming; Huo, Yu; Han, Ya-Ling

    2012-01-01

    Background The protective effects against reperfusion injury of cardioprotective drugs have recently been evaluated and found to be inadequate. Guanxinshutong (GXST), a combination of the traditional herb and Mongolian medicine, is effective and safe in treating angina pectoris in clinical trials. We assess the cardioprotective effects of GXST against myocardial ischemia and reperfusion (MI/R) injury in rats and explore its possible mechanism. Methods Forty-five male Sprague Dawley rats were randomized into three groups: non-MI/R group (Sham, n = 15), MI/R group treated with vehicle (Control, n = 15) and MI/R group treated with GXST (Drug, n = 15). MI/R was induced by ligation of the left anterior descending coronary artery (LAD) for 30 minutes, followed by 2/24 hour reperfusion in the Control and Drug groups. In the Sham group, the LAD was exposed without occlusion. GXST powder (in the Drug group) or saline (in the Control and Sham groups) were administered via direct gastric gavage from 7 day prior to surgery. Blood samples were collected from the carotid artery (10 rats each group) after 2 hours of reperfusion, to determine the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and intercellular adhesion molecule-1 (ICAM-1) using enzyme-linked immunosorbent assays. The animals were then sacrificed and the hearts were harvested for histopathology and western blot analysis. Infarct size was measured in the remaining five rats in each group after 24 hours reperfusion. Results GXST significantly decreased levels of TNF-α, IL-1β, IL-6, ICAM-1, apoptosis index (AI) and infarct size. GXST also obviously inhibited nuclear factor kappa B (NF-κB) activity when compared with the Control group (all P < 0.05). Conclusions GXST is effective in protecting the myocardium against MI/R injury in rats. Its possible cardioprotective mechanism involves inhibition of the inflammatory response and apoptosis following MI/R injury. PMID

  6. Cardiac-Specific SOCS3 Deletion Prevents In Vivo Myocardial Ischemia Reperfusion Injury through Sustained Activation of Cardioprotective Signaling Molecules

    PubMed Central

    Nagata, Takanobu; Yasukawa, Hideo; Kyogoku, Sachiko; Oba, Toyoharu; Takahashi, Jinya; Nohara, Shoichiro; Minami, Tomoko; Mawatari, Kazutoshi; Sugi, Yusuke; Shimozono, Koutatsu; Pradervand, Sylvain; Hoshijima, Masahiko; Aoki, Hiroki; Fukumoto, Yoshihiro; Imaizumi, Tsutomu

    2015-01-01

    Myocardial ischemia reperfusion injury (IRI) adversely affects cardiac performance and the prognosis of patients with acute myocardial infarction. Although myocardial signal transducer and activator of transcription (STAT) 3 is potently cardioprotective during IRI, the inhibitory mechanism responsible for its activation is largely unknown. The present study aimed to investigate the role of the myocardial suppressor of cytokine signaling (SOCS)-3, an intrinsic negative feedback regulator of the Janus kinase (JAK)-STAT signaling pathway, in the development of myocardial IRI. Myocardial IRI was induced in mice by ligating the left anterior descending coronary artery for 1 h, followed by different reperfusion times. One hour after reperfusion, the rapid expression of JAK-STAT–activating cytokines was observed. We precisely evaluated the phosphorylation of cardioprotective signaling molecules and the expression of SOCS3 during IRI and then induced myocardial IRI in wild-type and cardiac-specific SOCS3 knockout mice (SOCS3-CKO). The activation of STAT3, AKT, and ERK1/2 rapidly peaked and promptly decreased during IRI. This decrease correlated with the induction of SOCS3 expression up to 24 h after IRI in wild-type mice. The infarct size 24 h after reperfusion was significantly reduced in SOCS3-CKO compared with wild-type mice. In SOCS3-CKO mice, STAT3, AKT, and ERK1/2 phosphorylation was sustained, myocardial apoptosis was prevented, and the expression of anti-apoptotic Bcl-2 family member myeloid cell leukemia-1 (Mcl-1) was augmented. Cardiac-specific SOCS3 deletion led to the sustained activation of cardioprotective signaling molecules including and prevented myocardial apoptosis and injury during IRI. Our findings suggest that SOCS3 may represent a key factor that exacerbates the development of myocardial IRI. PMID:26010537

  7. Metformin for endometrial hyperplasia: a Cochrane protocol

    PubMed Central

    Clement, Naomi S; Oliver, Thomas R W; Shiwani, Hunain; Saner, Juliane R F; Mulvaney, Caroline A; Atiomo, William

    2016-01-01

    Introduction Endometrial hyperplasia is a precancerous lesion of the endometrium, commonly presenting with uterine bleeding. If managed expectantly, it frequently progresses to endometrial carcinoma, rates of which are increasing dramatically worldwide. However, the established treatment for endometrial hyperplasia (progestogens) involves multiple side effects and leaves the risk of recurrence. Metformin is the most commonly used oral hypoglycaemic agent in type 2 diabetes mellitus. It has also been linked to the reversal of endometrial hyperplasia and may therefore contribute to decreasing the prevalence of endometrial carcinoma without the fertility and side effect consequences of current therapies. However, the efficacy and safety of metformin being used for this therapeutic target is unclear and, therefore, this systematic review will aim to determine this. Methods and analysis We will search the following trials and databases with no language restrictions: Cochrane Gynaecology and Fertility Specialised Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; EBSCO Cumulative Index to Nursing and Allied Health Literature; PubMed; Google Scholar; ClinicalTrials.gov; the WHO International Trials Registry Platform portal; OpenGrey and the Latin American and Caribbean Health Sciences Literature (LILACS). We will include randomised controlled trials (RCTs) of use of metformin compared with a placebo or no treatment, conventional medical treatment (eg, progestogens) or any other active intervention. Two review authors will independently assess the trial eligibility, risk of bias and extract appropriate data points. Trial authors will be contacted for additional data. The primary review outcome is the regression of endometrial hyperplasia histology towards normal histology. Secondary outcomes include hysterectomy rate; abnormal uterine bleeding; quality of life scores and adverse reactions to treatments. Ethics and dissemination

  8. Development of pectinate-ispagula mucilage mucoadhesive beads of metformin HCl by central composite design.

    PubMed

    Nayak, Amit Kumar; Pal, Dilipkumar; Santra, Kousik

    2014-05-01

    Ionotropically-gelled mucoadhesive beads of metformin HCl composed of low methoxy (LM) pectin-ispaghula husk mucilage (IHM) polymer-blend was developed and optimized using central composite design (spherical type, single center point, and α=1.414). Effects of LM pectin and IHM amounts on drug encapsulation efficiency (DEE) and cumulative drug release at 10h (R10h) were analysed using response surface methodology. The optimized beads containing metformin HCl (F-O) showed DEE of 86.98 ± 3.26% and R10h of 47.20 ± 1.28%. All these beads exhibited suitable controlled in vitro sustained drug release pattern with super case-II transport mechanism over 10h. These beads were also characterized by SEM and FTIR. The optimized beads also exhibited pH-dependent swelling, good mucoadhesivity with goat intestinal mucosa and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration, which could possibly be lucrative in terms of prolonged systemic absorption of metformin HCl maintaining tight blood glucose level and advanced patient compliance. PMID:24560618

  9. CGRRF1 as a novel biomarker of tissue response to metformin in the context of obesity

    PubMed Central

    Zhang, Qian; Schmandt, Rosemarie; Celestino, Joseph; McCampbell, Adrienne; Yates, Melinda S.; Urbauer, Diana L.; Broaddus, Russell R.; Loose, David S.; Shipley, Gregory L.; Lu, Karen H.

    2014-01-01

    Objective Obesity-associated hyperestrogenism and hyperinsulinemia contribute significantly to the pathogenesis of endometrial cancer. We recently demonstrated that metformin, a drug long used for treatment of type 2 diabetes, attenuates both insulin- and estrogen-mediated proliferative signaling in the obese rat endometrium. In this study, we sought to identify tissue biomarkers that may prove clinically useful to predict tissue response for both prevention and therapeutic studies. We identified CGRRF1 (Cell growth regulator with ring finger domain 1) as a novel metformin-responsive gene and characterized its possible role in endometrial cancer prevention. Methods CGRRF1 mRNA expression was evaluated by RT-qPCR in the endometrium of obese and lean rats, and also in normal and malignant human endometrium. CGRRF1 levels were genetically manipulated in endometrial cancer cells, and its effects on proliferation and apoptosis were evaluated by MTT and western blot. Results CGRRF1 is significantly induced by metformin treatment in the obese rat endometrium. In vitro studies demonstrate that overexpression of CGRRF1 inhibits endometrial cancer cell proliferation. Analysis of human endometrial tumors reveal that CGRRF1 expression is significantly lower in hyperplasia, Grade 1, Grade 2, Grade 3, MMMT, and UPSC endometrial tumors compared to normal human endometrium (p<0.05), suggesting that loss of CGRRF1 is associated with the presence of disease. Conclusion CGRRF1 represents a novel, reproducible tissue marker of metformin response in the obese endometrium. Furthermore, our preliminary data suggests that up-regulation of CGRRF1 expression may prove clinically useful in the prevention or treatment of endometrial cancer. PMID:24680596

  10. Opioid receptors and cardioprotection – ‘opioidergic conditioning’ of the heart

    PubMed Central

    Headrick, John P; See Hoe, Louise E; Du Toit, Eugene F; Peart, Jason N

    2015-01-01

    Ischaemic heart disease (IHD) remains a major cause of morbidity/mortality globally, firmly established in Westernized or ‘developed’ countries and rising in prevalence in developing nations. Thus, cardioprotective therapies to limit myocardial damage with associated ischaemia–reperfusion (I–R), during infarction or surgical ischaemia, is a very important, although still elusive, clinical goal. The opioid receptor system, encompassing the δ (vas deferens), κ (ketocyclazocine) and μ (morphine) opioid receptors and their endogenous opioid ligands (endorphins, dynorphins, enkephalins), appears as a logical candidate for such exploitation. This regulatory system may orchestrate organism and organ responses to stress, induces mammalian hibernation and associated metabolic protection, triggers powerful adaptive stress resistance in response to ischaemia/hypoxia (preconditioning), and mediates cardiac benefit stemming from physical activity. In addition to direct myocardial actions, central opioid receptor signalling may also enhance the ability of the heart to withstand I–R injury. The δ- and κ-opioid receptors are strongly implicated in cardioprotection across models and species (including anti-infarct and anti-arrhythmic actions), with mixed evidence for μ opioid receptor-dependent protection in animal and human tissues. A small number of clinical trials have provided evidence of cardiac benefit from morphine or remifentanil in cardiopulmonary bypass or coronary angioplasty patients, although further trials of subtype-specific opioid receptor agonists are needed. The precise roles and utility of this GPCR family in healthy and diseased human myocardium, and in mediating central and peripheral survival responses, warrant further investigation, as do the putative negative influences of ageing, IHD co-morbidities, and relevant drugs on opioid receptor signalling and protective responses. PMID:25521834

  11. Cardioprotection by H2S Donors: Nitric Oxide-Dependent and ‑Independent Mechanisms.

    PubMed

    Chatzianastasiou, Athanasia; Bibli, Sofia-Iris; Andreadou, Ioanna; Efentakis, Panagiotis; Kaludercic, Nina; Wood, Mark E; Whiteman, Matthew; Di Lisa, Fabio; Daiber, Andreas; Manolopoulos, Vangelis G; Szabó, Csaba; Papapetropoulos, Andreas

    2016-09-01

    Hydrogen sulfide (H2S) is a signaling molecule with protective effects in the cardiovascular system. To harness the therapeutic potential of H2S, a number of donors have been developed. The present study compares the cardioprotective actions of representative H2S donors from different classes and studies their mechanisms of action in myocardial injury in vitro and in vivo. Exposure of cardiomyocytes to H2O2 led to significant cytotoxicity, which was inhibited by sodium sulfide (Na2S), thiovaline (TV), GYY4137 [morpholin-4-ium 4 methoxyphenyl(morpholino) phosphinodithioate], and AP39 [(10-oxo-10-(4-(3-thioxo-3H-1,2-dithiol5yl)phenoxy)decyl) triphenylphospho-nium bromide]. Inhibition of nitric oxide (NO) synthesis prevented the cytoprotective effects of Na2S and TV, but not GYY4137 and AP39, against H2O2-induced cardiomyocyte injury. Mice subjected to left anterior descending coronary ligation were protected from ischemia-reperfusion injury by the H2S donors tested. Inhibition of nitric oxide synthase (NOS) in vivo blocked only the beneficial effect of Na2S. Moreover, Na2S, but not AP39, administration enhanced the phosphorylation of endothelial NOS and vasodilator-associated phosphoprotein. Both Na2S and AP39 reduced infarct size in mice lacking cyclophilin-D (CypD), a modulator of the mitochondrial permeability transition pore (PTP). Nevertheless, only AP39 displayed a direct effect on mitochondria by increasing the mitochondrial Ca(2+) retention capacity, which is evidence of decreased propensity to undergo permeability transition. We conclude that although all the H2S donors we tested limited infarct size, the pathways involved were not conserved. Na2S had no direct effects on PTP opening, and its action was nitric oxide dependent. In contrast, the cardioprotection exhibited by AP39 could result from a direct inhibitory effect on PTP acting at a site different than CypD. PMID:27342567

  12. Oxidative Stress, Redox Signaling, and Metal Chelation in Anthracycline Cardiotoxicity and Pharmacological Cardioprotection

    PubMed Central

    Popelová, Olga; Vávrová, Anna; Jirkovský, Eduard; Kovaříková, Petra; Geršl, Vladimír

    2013-01-01

    Abstract Significance: Anthracyclines (doxorubicin, daunorubicin, or epirubicin) rank among the most effective anticancer drugs, but their clinical usefulness is hampered by the risk of cardiotoxicity. The most feared are the chronic forms of cardiotoxicity, characterized by irreversible cardiac damage and congestive heart failure. Although the pathogenesis of anthracycline cardiotoxicity seems to be complex, the pivotal role has been traditionally attributed to the iron-mediated formation of reactive oxygen species (ROS). In clinics, the bisdioxopiperazine agent dexrazoxane (ICRF-187) reduces the risk of anthracycline cardiotoxicity without a significant effect on response to chemotherapy. The prevailing concept describes dexrazoxane as a prodrug undergoing bioactivation to an iron-chelating agent ADR-925, which may inhibit anthracycline-induced ROS formation and oxidative damage to cardiomyocytes. Recent Advances: A considerable body of evidence points to mitochondria as the key targets for anthracycline cardiotoxicity, and therefore it could be also crucial for effective cardioprotection. Numerous antioxidants and several iron chelators have been tested in vitro and in vivo with variable outcomes. None of these compounds have matched or even surpassed the effectiveness of dexrazoxane in chronic anthracycline cardiotoxicity settings, despite being stronger chelators and/or antioxidants. Critical Issues: The interpretation of many findings is complicated by the heterogeneity of experimental models and frequent employment of acute high-dose treatments with limited translatability to clinical practice. Future Directions: Dexrazoxane may be the key to the enigma of anthracycline cardiotoxicity, and therefore it warrants further investigation, including the search for alternative/complementary modes of cardioprotective action beyond simple iron chelation. Antioxid. Redox Signal. 00, 000–000. PMID:22794198

  13. IGF1/insulin receptor kinase inhibition by BMS-536924 is better tolerated than alloxan-induced hypoinsulinemia and more effective than metformin in the treatment of experimental insulin-responsive breast cancer.

    PubMed

    Dool, Carly Jade; Mashhedi, Haider; Zakikhani, Mahvash; David, Stéphanie; Zhao, Yunhua; Birman, Elena; Carboni, Joan M; Gottardis, Marco; Blouin, Marie-José; Pollak, Michael

    2011-12-01

    Epidemiologic and experimental evidence suggest that a subset of breast cancer is insulin responsive, but it is unclear whether safe and effective therapies that target the insulin receptor (IR), which is homologous to oncogenes of the tyrosine kinase class, can be developed. We demonstrate that both pharmacologic inhibition of IR family tyrosine kinase activity and insulin deficiency have anti-neoplastic activity in a model of insulin-responsive breast cancer. Unexpectedly, in contrast to insulin deficiency, pharmacologic IR family inhibition does not lead to significant hyperglycemia and is well tolerated. We show that pharmacokinetic factors explain the tolerability of receptor inhibition relative to insulin deficiency, as the small molecule receptor kinase inhibitor BMS-536924 does not accumulate in muscle at levels sufficient to block insulin-stimulated glucose uptake. Metformin, which lowers insulin levels only in settings of hyperinsulinemia, had minimal activity in this normoinsulinemic model. These findings highlight the importance of tissue-specific drug accumulation as a determinant of efficacy and toxicity of tyrosine kinase inhibitors and suggest that therapeutic targeting of the IR family for cancer treatment is practical. PMID:21946410

  14. Metformin Reverses Development of Pulmonary Hypertension via Aromatase Inhibition.

    PubMed

    Dean, Afshan; Nilsen, Margaret; Loughlin, Lynn; Salt, Ian P; MacLean, Margaret R

    2016-08-01

    Females are more susceptible to pulmonary arterial hypertension than males, although the reasons remain unclear. The hypoglycemic drug, metformin, is reported to have multiple actions, including the inhibition of aromatase and stimulation of AMP-activated protein kinase. Inhibition of aromatase using anastrazole is protective in experimental pulmonary hypertension but whether metformin attenuates pulmonary hypertension through this mechanism remains unknown. We investigated whether metformin affected aromatase activity and if it could reduce the development of pulmonary hypertension in the sugen 5416/hypoxic rat model. We also investigated its influence on proliferation in human pulmonary arterial smooth muscle cells. Metformin reversed right ventricular systolic pressure, right ventricular hypertrophy, and decreased pulmonary vascular remodeling in the rat. Furthermore, metformin increased rat lung AMP-activated protein kinase signaling, decreased lung and circulating estrogen levels, levels of aromatase, the estrogen metabolizing enzyme; cytochrome P450 1B1 and its transcription factor; the aryl hydrocarbon receptor. In human pulmonary arterial smooth muscle cells, metformin decreased proliferation and decreased estrogen synthesis by decreasing aromatase activity through the PII promoter site of Cyp19a1 Thus, we report for the first time that metformin can reverse pulmonary hypertension through inhibition of aromatase and estrogen synthesis in a manner likely to be mediated by AMP-activated protein kinase. PMID:27296990

  15. Characterization of spray dried bioadhesive metformin microparticles for oromucosal administration.

    PubMed

    Sander, Camilla; Madsen, Katrine Dragsbæk; Hyrup, Birgitte; Nielsen, Hanne Mørck; Rantanen, Jukka; Jacobsen, Jette

    2013-11-01

    Delivery of drugs into or via the oral cavity offers some distinct advantages due to the easy access to the oral mucosa, fast onset of action, and avoidance of hepatic and intestinal degradation mechanisms. To overcome the effective removal mechanisms existing in this area, bioadhesive drug delivery systems are considered a promising approach as they facilitate a close contact between the drug and the oral mucosa. In this study, bioadhesive chitosan-based microparticles of metformin hydrochloride were prepared by spray drying aqueous dispersions with different chitosan:metformin ratios and chitosan grades with increasing molecular weights. A recently developed ex vivo flow retention model with porcine buccal mucosa was used to evaluate the bioadhesive properties of spray dried microparticles. An important outcome of this study was that microparticles with the desired metformin content could be prepared and analyzed using the ex vivo retention model. We observed an increase in metformin retention on porcine mucosa with increasing chitosan:metformin ratios, while no effect of increasing the chitosan molecular weight was found. Rheological characterization of feeds for spray drying was performed and used for designing the microparticles. This way, novel microparticles with similar particle size distribution, high encapsulation efficiencies, and low moisture content were obtained independent of the chitosan:metformin ratio and the chitosan molecular weight. In conclusion, chitosan:metformin microparticles with significant bioadhesive properties on porcine buccal mucosa were developed. PMID:23774184

  16. Short-Term Continuous Subcutaneous Insulin Infusion Combined with Insulin Sensitizers Rosiglitazone, Metformin, or Antioxidant α-Lipoic Acid in Patients with Newly Diagnosed Type 2 Diabetes Mellitus

    PubMed Central

    Huang, Zhimin; Wan, Xuesi; Liu, Juan; Deng, Wanping; Chen, Ailing; Liu, Liehua; Liu, Jianbin; Wei, Guohong; Li, Hai; Fang, Donghong

    2013-01-01

    Abstract Background Short-term continuous subcutaneous insulin infusion (CSII) in patients with newly diagnosed type 2 diabetes has been proved effective in improving metabolic control and β-cell function, thus inducing long-term drug-free remission. A randomized controlled trial was conducted to investigate whether CSII in combination with rosiglitazone, metformin, or α-lipoic acid separately brings about extra benefits. Patients and Methods One hundred sixty patients with newly diagnosed type 2 diabetes were randomized to one of four treatment groups: CSII alone, CSII in combination with rosiglitazone or metformin for 3 months, or CSII with α-lipoic acid intravenous infusion for 2 weeks. Duration of CSII treatment was identical in the four groups. Glucose and lipid profiles, homeostasis model assessment (HOMA) indices, acute insulin response (AIR), intramyocellular lipid (IMCL) level, and malondialdehyde level were compared before and after intervention. Results The near-normoglycemia rate at the third month in CSII alone and that in combination with rosiglitazone, metformin, or α-lipoic acid was 72.5%, 87.5%, 90%, and 75%, respectively (metformin group vs. CSII alone, P=0.045). The metformin group achieved euglycemia in a shorter time (2.6±1.3 vs. 3.7±1.8 days, P=0.020) with less daily insulin dosage and was more powerful in lowering total cholesterol, increasing AIR and HOMA β-cell function, whereas reduction of IMCL in the soleus was more obvious in the rosiglitazone group but not in the metformin group. The efficacy of combination with α-lipoic acid was similar to that of CSII alone. Conclusions Short-term CSII in combination with rosiglitazone or metformin is superior to CSII alone, yet the efficacy of the two differs in some way, whereas that with α-lipoic acid might not have an additive effect. PMID:23991629

  17. Metformin Enhances the Therapy Effects of Anti-IGF-1R mAb Figitumumab to NSCLC.

    PubMed

    Cao, Hongxin; Dong, Wei; Qu, Xiao; Shen, Hongchang; Xu, Jun; Zhu, Linhai; Liu, Qi; Du, Jiajun

    2016-01-01

    The insulin-like growth factor (IGF) signaling system plays a critical role in tumorigenesis, highlighting the potential of targeting IGF-1R as an anti-cancer therapy. Although multiple anti-IGF-1R monoclonal antibody (mAb) drugs have been developed, challenges remain in the validation of the therapeutic effects and understanding the molecular mechanism of these mAbs. Herein, we conducted a study to validate the effect of Figitumumab (CP), an anti-IGF-1R mAb, in a panel of non-small cell lung cancer (NSCLC) cell lines. We found all tested cell lines were sensitive to CP, and CP could block IGF-1R and the downstream PI3K/AKT pathway activation. Unexpectedly, we found CP could activate ERK signaling pathway in IGF-1R kinase independent manner, which we further verified was mainly mediated by β-arrestin2. We also investigated the anti-tumor effect of metformin alone as well as its combination with CP to target NSCLC. Metformin could target IGF-1R signaling pathway by attenuating PI3K/AKT and MEK/ERK signaling pathways and down-regulating IGF-1R. Finally, we found that combining metformin with CP could further induce IGF-1R down-regulation and was more effective to target NSCLC cells. Our data suggests the combining of metformin with CP has additive therapeutic value against NSCLC. PMID:27488947

  18. Clinical utility and patient considerations in the use of the sitagliptin–metformin combination in Chinese patients

    PubMed Central

    Du, Qiang; Wang, Yan-Jun; Yang, Sheng; Han, Ping

    2015-01-01

    The prevalence of diabetes mellitus (DM) continues to increase each year. However, the efficacy of glucose-lowering therapies remains unsatisfactory. Moreover, the clinical characteristics and manifestations of DM in Chinese patients are different from those in Western patients. Thus, it is imperative to develop an optimal treatment protocol for lowering blood glucose levels in Chinese patients with DM. Sitagliptin has been used in People’s Republic of China, and sitagliptin and metformin combination therapy may not alter their individual pharmacokinetics. To date, several clinical trials undertaken to investigate the efficacy of sitagliptin and metformin combination therapy have revealed that it effectively controlled glycated hemoglobin, fasting plasma glucose, and postprandial plasma glucose levels to a greater extent than sitagliptin or metformin alone. In addition, the combined therapy was well tolerated and induced few side effects, which were largely mild. Furthermore, the combined therapy was easy to administer, and the patients receiving this therapy showed good compliance. Therefore, for Chinese patients with type 2 DM, sitagliptin and metformin combination therapy is preferred. PMID:25709414

  19. Metformin Enhances the Therapy Effects of Anti-IGF-1R mAb Figitumumab to NSCLC

    PubMed Central

    Cao, Hongxin; Dong, Wei; Qu, Xiao; Shen, Hongchang; Xu, Jun; Zhu, Linhai; Liu, Qi; Du, Jiajun

    2016-01-01

    The insulin-like growth factor (IGF) signaling system plays a critical role in tumorigenesis, highlighting the potential of targeting IGF-1R as an anti-cancer therapy. Although multiple anti-IGF-1R monoclonal antibody (mAb) drugs have been developed, challenges remain in the validation of the therapeutic effects and understanding the molecular mechanism of these mAbs. Herein, we conducted a study to validate the effect of Figitumumab (CP), an anti-IGF-1R mAb, in a panel of non-small cell lung cancer (NSCLC) cell lines. We found all tested cell lines were sensitive to CP, and CP could block IGF-1R and the downstream PI3K/AKT pathway activation. Unexpectedly, we found CP could activate ERK signaling pathway in IGF-1R kinase independent manner, which we further verified was mainly mediated by β-arrestin2. We also investigated the anti-tumor effect of metformin alone as well as its combination with CP to target NSCLC. Metformin could target IGF-1R signaling pathway by attenuating PI3K/AKT and MEK/ERK signaling pathways and down-regulating IGF-1R. Finally, we found that combining metformin with CP could further induce IGF-1R down-regulation and was more effective to target NSCLC cells. Our data suggests the combining of metformin with CP has additive therapeutic value against NSCLC. PMID:27488947

  20. Paradoxic effects of metformin on endothelial cells and angiogenesis.

    PubMed

    Dallaglio, Katiuscia; Bruno, Antonino; Cantelmo, Anna R; Esposito, Alessia I; Ruggiero, Luca; Orecchioni, Stefania; Calleri, Angelica; Bertolini, Francesco; Pfeffer, Ulrich; Noonan, Douglas M; Albini, Adriana

    2014-05-01

    The biguanide metformin is used in type 2 diabetes management and has gained significant attention as a potential cancer preventive agent. Angioprevention represents a mechanism of chemoprevention, yet conflicting data concerning the antiangiogenic action of metformin have emerged. Here, we clarify some of the contradictory effects of metformin on endothelial cells and angiogenesis, using in vitro and in vivo assays combined with transcriptomic and protein array approaches. Metformin inhibits formation of capillary-like networks by endothelial cells; this effect is partially dependent on the energy sensor adenosine-monophosphate-activated protein kinase (AMPK) as shown by small interfering RNA knockdown. Gene expression profiling of human umbilical vein endothelial cells revealed a paradoxical modulation of several angiogenesis-associated genes and proteins by metformin, with short-term induction of vascular endothelial growth factor (VEGF), cyclooxygenase 2 and CXC chemokine receptor 4 at the messenger RNA level and downregulation of ADAMTS1. Antibody array analysis shows an essentially opposite regulation of numerous angiogenesis-associated proteins in endothelial and breast cancer cells including interleukin-8, angiogenin and TIMP-1, as well as selective regulation of angiopioetin-1, -2, endoglin and others. Endothelial cell production of the cytochrome P450 member CYP1B1 is upregulated by tumor cell supernatants in an AMPK-dependent manner, metformin blocks this effect. Metformin inhibits VEGF-dependent activation of extracellular signal-regulated kinase 1/2, and the inhibition of AMPK activity abrogates this event. Metformin hinders angiogenesis in matrigel pellets in vivo, prevents the microvessel density increase observed in obese mice on a high-fat diet, downregulating the number of white adipose tissue endothelial precursor cells. Our data show that metformin has an antiangiogenic activity in vitro and in vivo associated with a contradictory short

  1. Anti-diabetic drug metformin: challenges and perspectives for cancer therapy.

    PubMed

    Snima, Kaniyampadi Sreenivasan; Pillai, Prathesha; Cherian, Aleena Mary; Nair, Shantikumar V; Lakshmanan, Vinoth-Kumar

    2014-01-01

    Metformin, a biguanide, is a commonly administered drug for the management of type 2 diabetes mellitus. The drug received tremendous recognition, when retrospective studies proved metformin-associated reduction in cancer risk. Metformin has potential anticancer effects and an ability to suppress tumor growth both in vitro and in vivo. Activation of LKB1/AMPK pathway and cancer stem cell destruction along with cell cycle arrest and apoptosis induction are the proposed mechanisms of anticancer potential of metformin. Nanotechnology approaches have also been adopted for metformin delivery to cancer cells. This review directs on the application of metformin for the therapy of various cancers and also the different pathways responsible for the metformin derived anticancer effect. It also focuses on the pharmacological applications of metformin and the nanotechnology approaches for metformin delivery. PMID:25329671

  2. Sphingosine Kinase and Sphingosine 1-Phosphate in Cardioprotection

    PubMed Central

    Karliner, Joel S.

    2010-01-01

    Activation of sphingosine kinase/sphingosine 1-phosphate– mediated signaling has emerged as a critical cardioprotective pathway in response to acute ischemia/reperfusion injury. Application of exogenous sphingosine 1-phosphate (S1P) in cultured cardiac myocytes subjected to hypoxia or treatment of isolated hearts either before ischemia or at the onset of reperfusion (pharmacologic preconditioning or postconditioning) exerts prosurvival effects. Synthetic congeners of S1P mimic these responses. Gene-targeted mice null for the sphingosine kinase 1 isoform whose hearts are subjected to ischemia/reperfusion injury exhibit increased infarct size and respond poorly either to ischemic preconditioning or to ischemic postconditioning. Measurements of cardiac sphingosine kinase activity and S1P parallel these observations. High-density lipoprotein is a major carrier of S1P, and studies of hearts in which selected S1P receptors have been deleted implicate the S1P cargo of high-density lipoprotein in cardioprotection. These observations have considerable relevance for future therapeutic approaches to acute and chronic myocardial injury. PMID:19247197

  3. Parkinson's disease proteins: Novel mitochondrial targets for cardioprotection

    PubMed Central

    Mukherjee, Uma A.; Ong, Sang-Bing; Ong, Sang-Ging; Hausenloy, Derek J.

    2015-01-01

    Ischemic heart disease (IHD) is the leading cause of death and disability worldwide. Therefore, novel therapeutic targets for protecting the heart against acute ischemia/reperfusion injury (IRI) are required to attenuate cardiomyocyte death, preserve myocardial function, and prevent the onset of heart failure. In this regard, a specific group of mitochondrial proteins, which have been linked to familial forms of Parkinson's disease (PD), may provide novel therapeutic targets for cardioprotection. In dopaminergic neurons of the substantia nigra, these PD proteins, which include Parkin, PINK1, DJ-1, LRRK2, and α-synuclein, play essential roles in preventing cell death—through maintaining normal mitochondrial function, protecting against oxidative stress, mediating mitophagy, and preventing apoptosis. These rare familial forms of PD may therefore provide important insights into the pathophysiology underlying mitochondrial dysfunction and the development of PD. Interestingly, these PD proteins are also present in the heart, but their role in myocardial health and disease is not clear. In this article, we review the role of these PD proteins in the heart and explore their potential as novel mitochondrial targets for cardioprotection. PMID:26481155

  4. Evaluation of the potential cardioprotective activity of some Saudi plants against doxorubicin toxicity.

    PubMed

    Ashour, Osama M; Abdel-Naim, Ashraf B; Abdallah, Hossam M; Nagy, Ayman A; Mohamadin, Ahmed M; Abdel-Sattar, Essam A

    2012-01-01

    Doxorubicin (DOX) is an anthracycline antibiotic widely used as a chemotherapeutic agent in the treatment of several tumours. However, its cardiac toxicity limits its use at maximum therapeutic doses. Most studies implicated increased oxidative stress as the major determinant of DOX cardiotoxicity. The local Saudi flora is very rich in a variety of plants of quite known folkloric or traditional medicinal uses. Tribulus macropterus Boiss., Olea europaea L. subsp. africana (Mill.) P. S. Green, Tamarix aphylla (L.) H. Karst., Cynomorium coccineum L., Cordia myxa L., Calligonum comosum L' Hér, and Withania somnifera (L.) Dunal are Saudi plants known to have antioxidant activities. The aim of the current study was to explore the potential protective effects of methanolic extracts of these seven Saudi plants against DOX-induced cardiotoxicity in rats. Two plants showed promising cardioprotective potential in the order Calligonum comosum > Cordia myxa. The two plant extracts showed potent in vitro radical scavenging and antioxidant properties. They significantly protected against DOX-induced alterations in cardiac oxidative stress markers (GSH and MDA) and cardiac serum markers (CK-MB and LDH activities). Additionally, histopathological examination indicated a protection against DOX-induced cardiotoxicity. In conclusion, C. comosum and C. myxa exerted protective activity against DOX-induced cardiotoxicity, which is, at least partly, due to their antioxidant effect. PMID:22888535

  5. Induction of the matricellular protein CCN1 through RhoA and MRTF-A contributes to ischemic cardioprotection.

    PubMed

    Zhao, Xia; Ding, Eric Y; Yu, Olivia M; Xiang, Sunny Y; Tan-Sah, Valerie P; Yung, Bryan S; Hedgpeth, Joe; Neubig, Richard R; Lau, Lester F; Brown, Joan Heller; Miyamoto, Shigeki

    2014-10-01

    Activation of RhoA, a low molecular-weight G-protein, plays an important role in protecting the heart against ischemic stress. Studies using non-cardiac cells demonstrate that the expression and subsequent secretion of the matric