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Abstract
Metformin is the first-line treatment for type 2 diabetes. Results from several clinical studies have indicated that type 2 diabetic patients treated with metformin might have a lower cancer risk. One of the primary metabolic changes observed in malignant cell transformation is an increased catabolic glucose metabolism. In this context, once it has entered the cell through organic cation transporters, metformin decreases mitochondrial respiration chain activity and ATP production that, in turn, activates AMP-activated protein kinase, which regulates energy homeostasis. In addition, metformin reduces cellular energy availability and glucose entrapment by inhibiting hexokinase-II, which catalyses the glucose phosphorylation reaction. In this review, we discuss recent findings on molecular mechanisms that sustain the anticancer effect of metformin through regulation of glucose metabolism. In particular, we have focused on the emerging action of metformin on glycolysis in normal and cancer cells, with a drug discovery perspective.
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Affiliation(s)
- Barbara Salani
- Department of Internal Medicine (DIMI)University of Genova, Viale Benedetto XV/6, 16132 Genova, ItalyIRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro16132 Genova, ItalyDepartment of ExperimentalDiagnostic and Specialty Medicine (DIMES), Alma Mater Studiorum, University of Bologna, Bologna, ItalyCNR Institute of Organic Synthesis and Photoreactivity (ISOF)40129 Bologna, ItalyCNR Institute of Molecular Bioimaging and Physiology (IBFM)16132 Genova, ItalyDepartment of Health Science (DISSAL)University of Genova, 16132 Genova, Italy Department of Internal Medicine (DIMI)University of Genova, Viale Benedetto XV/6, 16132 Genova, ItalyIRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro16132 Genova, ItalyDepartment of ExperimentalDiagnostic and Specialty Medicine (DIMES), Alma Mater Studiorum, University of Bologna, Bologna, ItalyCNR Institute of Organic Synthesis and Photoreactivity (ISOF)40129 Bologna, ItalyCNR Institute of Molecular Bioimaging and Physiology (IBFM)16132 Genova, ItalyDepartment of Health Science (DISSAL)University of Genova, 16132 Genova, Italy
| | - Alberto Del Rio
- Department of Internal Medicine (DIMI)University of Genova, Viale Benedetto XV/6, 16132 Genova, ItalyIRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro16132 Genova, ItalyDepartment of ExperimentalDiagnostic and Specialty Medicine (DIMES), Alma Mater Studiorum, University of Bologna, Bologna, ItalyCNR Institute of Organic Synthesis and Photoreactivity (ISOF)40129 Bologna, ItalyCNR Institute of Molecular Bioimaging and Physiology (IBFM)16132 Genova, ItalyDepartment of Health Science (DISSAL)University of Genova, 16132 Genova, Italy Department of Internal Medicine (DIMI)University of Genova, Viale Benedetto XV/6, 16132 Genova, ItalyIRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro16132 Genova, ItalyDepartment of ExperimentalDiagnostic and Specialty Medicine (DIMES), Alma Mater Studiorum, University of Bologna, Bologna, ItalyCNR Institute of Organic Synthesis and Photoreactivity (ISOF)40129 Bologna, ItalyCNR Institute of Molecular Bioimaging and Physiology (IBFM)16132 Genova, ItalyDepartment of Health Science (DISSAL)University of Genova, 16132 Genova, Italy
| | - Cecilia Marini
- Department of Internal Medicine (DIMI)University of Genova, Viale Benedetto XV/6, 16132 Genova, ItalyIRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro16132 Genova, ItalyDepartment of ExperimentalDiagnostic and Specialty Medicine (DIMES), Alma Mater Studiorum, University of Bologna, Bologna, ItalyCNR Institute of Organic Synthesis and Photoreactivity (ISOF)40129 Bologna, ItalyCNR Institute of Molecular Bioimaging and Physiology (IBFM)16132 Genova, ItalyDepartment of Health Science (DISSAL)University of Genova, 16132 Genova, Italy
| | - Gianmario Sambuceti
- Department of Internal Medicine (DIMI)University of Genova, Viale Benedetto XV/6, 16132 Genova, ItalyIRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro16132 Genova, ItalyDepartment of ExperimentalDiagnostic and Specialty Medicine (DIMES), Alma Mater Studiorum, University of Bologna, Bologna, ItalyCNR Institute of Organic Synthesis and Photoreactivity (ISOF)40129 Bologna, ItalyCNR Institute of Molecular Bioimaging and Physiology (IBFM)16132 Genova, ItalyDepartment of Health Science (DISSAL)University of Genova, 16132 Genova, Italy Department of Internal Medicine (DIMI)University of Genova, Viale Benedetto XV/6, 16132 Genova, ItalyIRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro16132 Genova, ItalyDepartment of ExperimentalDiagnostic and Specialty Medicine (DIMES), Alma Mater Studiorum, University of Bologna, Bologna, ItalyCNR Institute of Organic Synthesis and Photoreactivity (ISOF)40129 Bologna, ItalyCNR Institute of Molecular Bioimaging and Physiology (IBFM)16132 Genova, ItalyDepartment of Health Science (DISSAL)University of Genova, 16132 Genova, Italy
| | - Renzo Cordera
- Department of Internal Medicine (DIMI)University of Genova, Viale Benedetto XV/6, 16132 Genova, ItalyIRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro16132 Genova, ItalyDepartment of ExperimentalDiagnostic and Specialty Medicine (DIMES), Alma Mater Studiorum, University of Bologna, Bologna, ItalyCNR Institute of Organic Synthesis and Photoreactivity (ISOF)40129 Bologna, ItalyCNR Institute of Molecular Bioimaging and Physiology (IBFM)16132 Genova, ItalyDepartment of Health Science (DISSAL)University of Genova, 16132 Genova, Italy Department of Internal Medicine (DIMI)University of Genova, Viale Benedetto XV/6, 16132 Genova, ItalyIRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro16132 Genova, ItalyDepartment of ExperimentalDiagnostic and Specialty Medicine (DIMES), Alma Mater Studiorum, University of Bologna, Bologna, ItalyCNR Institute of Organic Synthesis and Photoreactivity (ISOF)40129 Bologna, ItalyCNR Institute of Molecular Bioimaging and Physiology (IBFM)16132 Genova, ItalyDepartment of Health Science (DISSAL)University of Genova, 16132 Genova, Italy
| | - Davide Maggi
- Department of Internal Medicine (DIMI)University of Genova, Viale Benedetto XV/6, 16132 Genova, ItalyIRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro16132 Genova, ItalyDepartment of ExperimentalDiagnostic and Specialty Medicine (DIMES), Alma Mater Studiorum, University of Bologna, Bologna, ItalyCNR Institute of Organic Synthesis and Photoreactivity (ISOF)40129 Bologna, ItalyCNR Institute of Molecular Bioimaging and Physiology (IBFM)16132 Genova, ItalyDepartment of Health Science (DISSAL)University of Genova, 16132 Genova, Italy Department of Internal Medicine (DIMI)University of Genova, Viale Benedetto XV/6, 16132 Genova, ItalyIRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro16132 Genova, ItalyDepartment of ExperimentalDiagnostic and Specialty Medicine (DIMES), Alma Mater Studiorum, University of Bologna, Bologna, ItalyCNR Institute of Organic Synthesis and Photoreactivity (ISOF)40129 Bologna, ItalyCNR Institute of Molecular Bioimaging and Physiology (IBFM)16132 Genova, ItalyDepartment of Health Science (DISSAL)University of Genova, 16132 Genova, Italy
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Pojoga LH, Yao TM, Opsasnick LA, Garza AE, Reslan OM, Adler GK, Williams GH, Khalil RA. Dissociation of hyperglycemia from altered vascular contraction and relaxation mechanisms in caveolin-1 null mice. J Pharmacol Exp Ther 2013; 348:260-70. [PMID: 24281385 DOI: 10.1124/jpet.113.209189] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Hyperglycemia and endothelial dysfunction are associated with hypertension, but the specific causality and genetic underpinning are unclear. Caveolin-1 (cav-1) is a plasmalemmal anchoring protein and modulator of vascular function and glucose homeostasis. Cav-1 gene variants are associated with reduced insulin sensitivity in hypertensive individuals, and cav-1(-/-) mice show endothelial dysfunction, hyperglycemia, and increased blood pressure (BP). On the other hand, insulin-sensitizing therapy with metformin may inadequately control hyperglycemia while affecting the vascular outcome in certain patients with diabetes. To test whether the pressor and vascular changes in cav-1 deficiency states are related to hyperglycemia and to assess the vascular mechanisms of metformin under these conditions, wild-type (WT) and cav-1(-/-) mice were treated with either placebo or metformin (400 mg/kg daily for 21 days). BP and fasting blood glucose were in cav-1(-/-) > WT and did not change with metformin. Phenylephrine (Phe)- and KCl-induced aortic contraction was in cav-1(-/-) < WT; endothelium removal, the nitric-oxide synthase (NOS) blocker L-NAME (N(ω)-nitro-L-arginine methyl ester), or soluble guanylate cyclase (sGC) inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) enhanced Phe contraction, and metformin blunted this effect. Acetylcholine-induced relaxation was in cav-1(-/-) > WT, abolished by endothelium removal, L-NAME or ODQ, and reduced with metformin. Nitric oxide donor sodium nitroprusside was more potent in inducing relaxation in cav-1(-/-) than in WT, and metformin reversed this effect. Aortic eNOS, AMPK, and sGC were in cav-1(-/-) > WT, and metformin decreased total and phosphorylated eNOS and AMPK in cav-1(-/-). Thus, metformin inhibits both vascular contraction and NO-cGMP-dependent relaxation but does not affect BP or blood glucose in cav-1(-/-) mice, suggesting dissociation of hyperglycemia from altered vascular function in cav-1-deficiency states.
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Affiliation(s)
- Luminita H Pojoga
- Cardiovascular Endocrine Section, Endocrinology, Diabetes and Hypertension Division (L.H.P., T.M.Y., A.E.G., G.K.A., G.H.W.), and Division of Vascular and Endovascular Surgery (L.A.O., O.M.R., R.A.K.), Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts
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Cao R, Ding Q, Li P, Xue J, Zou Z, Huang J, Peng G. SHP1-mediated cell cycle redistribution inhibits radiosensitivity of non-small cell lung cancer. Radiat Oncol 2013; 8:178. [PMID: 23842094 PMCID: PMC3723552 DOI: 10.1186/1748-717x-8-178] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 07/02/2013] [Indexed: 12/25/2022] Open
Abstract
Background Radioresistance is the common cause for radiotherapy failure in non-small cell lung cancer (NSCLC), and the degree of radiosensitivity of tumor cells is different during different cell cycle phases. The objective of the present study was to investigate the effects of cell cycle redistribution in the establishment of radioresistance in NSCLC, as well as the signaling pathway of SH2 containing Tyrosine Phosphatase (SHP1). Methods A NSCLC subtype cell line, radioresistant A549 (A549S1), was induced by high-dose hypofractionated ionizing radiations. Radiosensitivity-related parameters, cell cycle distribution and expression of cell cycle-related proteins and SHP1 were investigated. siRNA was designed to down-regulate SHP1expression. Results Compared with native A549 cells, the proportion of cells in the S phase was increased, and cells in the G0/G1 phase were consequently decreased, however, the proportion of cells in the G2/M phase did not change in A549S1 cells. Moreover, the expression of SHP1, CDK4 and CylinD1 were significantly increased, while p16 was significantly down-regulated in A549S1 cells compared with native A549 cells. Furthermore, inhibition of SHP1 by siRNA increased the radiosensitivity of A549S1 cells, induced a G0/G1 phase arrest, down-regulated CDK4 and CylinD1expressions, and up-regulated p16 expression. Conclusions SHP1 decreases the radiosensitivity of NSCLC cells through affecting cell cycle distribution. This finding could unravel the molecular mechanism involved in NSCLC radioresistance.
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Affiliation(s)
- Rubo Cao
- Cancer Center of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No, 1227 Jiefang Dadao, Wuhan 430022, China
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Massollo M, Marini C, Brignone M, Emionite L, Salani B, Riondato M, Capitanio S, Fiz F, Democrito A, Amaro A, Morbelli S, Piana M, Maggi D, Cilli M, Pfeffer U, Sambuceti G. Metformin temporal and localized effects on gut glucose metabolism assessed using 18F-FDG PET in mice. J Nucl Med 2013; 54:259-66. [PMID: 23287574 DOI: 10.2967/jnumed.112.106666] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED In the course of metformin treatment, staging abdominal cancer lesions with (18)F-FDG PET images is often hindered by the presence of a high bowel radioactivity. The present study aimed to verify the mechanism underlying this phenomenon. METHODS Fifty-three mice were submitted to dynamic acquisitions of (18)F-FDG kinetics under fasting conditions. Three small-animal PET scans were obtained over a 4-mo study period. The animals were subdivided into 4 groups according to the following metformin administration protocol: group 1, untreated mice (n = 15); group 2, mice exposed to metformin treatment (750 mg/kg/d) for the 48 h before each PET study (pulsed, n = 10); group 3, mice treated for the whole study period (prolonged, n = 10); and group 4, mice in which prolonged treatment was interrupted 48 h before PET (interrupted, n = 8). The rate constant of (18)F-FDG uptake was estimated by Patlak analysis. At the end of the study, the ileum and colon were harvested, washed, and counted ex vivo. Two further groups, of 5 animals each, were included to evaluate the effect of prolonged metformin treatment on phosphorylated adenosine monophosphate (AMP)-activated protein kinase (pAMPK) form and gene expression for thioredoxin-interacting protein (TXNIP). RESULTS Pulsed treatment did not modify gut tracer retention with respect to the untreated group. Conversely, prolonged treatment induced a progressive increase in (18)F-FDG uptake that selectively involved the colonic wall, without any significant contamination of bowel content. This effect persisted after a complete drug washout in the interrupted group. These responses were paralleled by increased pAMPK availability and by reduced expression of TXNIP messenger RNA in colonic enterocytes exposed to prolonged metformin treatment. CONCLUSION Metformin causes a selective increase in colonic (18)F-FDG uptake. This effect appears after a relatively long period of treatment and persists soon after drug washout. Accordingly, the increased bowel glucose metabolism reflects a biologic response to chronic metformin treatment characterized by increased levels of pAMPK and reduced levels of TXNIP.
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Affiliation(s)
- Michela Massollo
- Nuclear Medicine, Department of Internal Medicine, University of Genoa and IRCCS San Martino-IST, 16132 Genoa, Italy
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Korsse SE, Peppelenbosch MP, van Veelen W. Targeting LKB1 signaling in cancer. Biochim Biophys Acta Rev Cancer 2012; 1835:194-210. [PMID: 23287572 DOI: 10.1016/j.bbcan.2012.12.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 12/18/2012] [Accepted: 12/20/2012] [Indexed: 12/13/2022]
Abstract
The serine/threonine kinase LKB1 is a master kinase involved in cellular responses such as energy metabolism, cell polarity and cell growth. LKB1 regulates these crucial cellular responses mainly via AMPK/mTOR signaling. Germ-line mutations in LKB1 are associated with the predisposition of the Peutz-Jeghers syndrome in which patients develop gastrointestinal hamartomas and have an enormously increased risk for developing gastrointestinal, breast and gynecological cancers. In addition, somatic inactivation of LKB1 has been associated with sporadic cancers such as lung cancer. The exact mechanisms of LKB1-mediated tumor suppression remain so far unidentified; however, the inability to activate AMPK and the resulting mTOR hyperactivation has been detected in PJS-associated lesions. Therefore, targeting LKB1 in cancer is now mainly focusing on the activation of AMPK and inactivation of mTOR. Preclinical in vitro and in vivo studies show encouraging results regarding these approaches, which have even progressed to the initiation of a few clinical trials. In this review, we describe the functions, regulation and downstream signaling of LKB1, and its role in hereditary and sporadic cancers. In addition, we provide an overview of several AMPK activators, mTOR inhibitors and additional mechanisms to target LKB1 signaling, and describe the effect of these compounds on cancer cells. Overall, we will explain the current strategies attempting to find a way of treating LKB1-associated cancer.
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Affiliation(s)
- S E Korsse
- Dept. of Gastroenterology and Hepatology, Erasmus Medical University Center, Rotterdam, The Netherlands
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