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insulin Rbeta (C-19) antibody

RRID:AB_631835

Antibody ID

AB_631835

Target Antigen

INSR human, mouse, rat

Proper Citation

(Santa Cruz Biotechnology Cat# sc-711, RRID:AB_631835)

Clonality

polyclonal antibody

Comments

Discontinued: 2016; validation status unknown check with seller; recommendations: ELISA; Immunofluorescence; Immunoprecipitation; Western Blot; Western Blotting, Immunoprecipitation, Immunofluorescence, ELISA

Clone ID

C-19

Host Organism

rabbit

Endothelial insulin receptor restoration rescues vascular function in male insulin receptor haploinsufficient mice.

  • Sengupta A
  • Endocrinology
  • 2018 May 15

Literature context:


Abstract:

Reduced systemic insulin signaling promotes endothelial dysfunction and diminished endogenous vascular repair. We asked whether restoration of endothelial insulin receptor expression could rescue this phenotype. Insulin receptor haploinsufficient mice (IRKO) were crossed with mice expressing a human insulin receptor transgene in the endothelium (hIRECO), to produce IRKO-hIRECO progeny. No metabolic differences were noted between IRKO and IRKO-hIRECO in glucose- and insulin-tolerance tests. In contrast with control IRKO littermates, IRKO-hIRECO exhibited normal blood pressure and aortic vasodilatation in response to acetylcholine, comparable to parameters noted in wild-type littermates. These phenotypic changes were associated with enhanced basal- and insulin-stimulated nitric oxide production. IRKO-hIRECO also demonstrated normalized endothelial repair after denuding arterial injury, which was associated with rescued endothelial cell migration in vitro, but not with changes in circulating progenitor populations or culture-derived myeloid angiogenic cells. These data show that restoration of endothelial insulin receptor expression alone is sufficient to prevent the vascular dysfunction caused by systemically reduced insulin signaling.

Funding information:
  • NIAID NIH HHS - SC1-AI-078559(United States)

Selective Androgen Receptor Modulator S42 Suppresses Prostate Cancer Cell Proliferation.

  • Kawanami T
  • Endocrinology
  • 2018 Apr 1

Literature context:


Abstract:

We previously identified the selective androgen receptor (AR) modulator S42, which does not stimulate prostate growth but has a beneficial effect on lipid metabolism. In the prostate cancer (PC) cell line LNCaP, S42 did not induce AR transactivation but antagonized 5α-dihydrotestosterone (DHT)‒induced AR activation. Next, we investigated whether S42 suppresses the growth of PC cell lines. Basal growth of LNCaP cells was significantly suppressed by treatment with S42 compared with vehicle, as determined by cell counting and 5-bromo-2'-deoxyuridine assays. The suppressive effect of S42 on cell growth was evident in the AR-positive PC cells LNCaP and 22Rv1 and was slightly observed even in the AR-negative PC-3 cells. However, S42 did not induce apoptosis as determined by the terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling assay. S42 had an even greater suppressive effect on DHT-dependent LNCaP cell proliferation than on basal proliferation (P < 0.05). DHT treatment increased the expression of phosphorylated extracellular signal-regulated kinase (ERK)-mitogen-activated protein kinase (MAPK), a major signaling molecule for PC proliferation, and this was significantly inhibited by S42. DHT also significantly upregulated AR, insulinlike growth factor-1 receptor (IGF-1R), and insulin receptor (IR)-β protein levels, which were similarly reduced by S42 treatment. Importantly, S42 administration to mice attenuated the growth of LNCaP tumors and reduced tumor expression of the prostate-specific antigen, P504S, Ki67, and phosphorylated ERK-MAPK. These data suggest that S42 attenuates LNCaP tumor growth not by inducing apoptosis but by inhibiting the expression of proliferation-related receptors, including IGF-1R, IR, and AR, and by suppressing ERK-MAPK activation. S42 may thus be a feasible candidate for PC treatment.

Funding information:
  • NHLBI NIH HHS - P01 HL32262-25(United States)

FoxO1 Is Required for Most of the Metabolic and Hormonal Perturbations Produced by Hepatic Insulin Receptor Deletion in Male Mice.

  • Ling AV
  • Endocrinology
  • 2018 Mar 1

Literature context:


Abstract:

Insulin coordinates the complex response to feeding, affecting numerous metabolic and hormonal pathways. Forkhead box protein O1 (FoxO1) is one of several signaling molecules downstream of insulin; FoxO1 drives gluconeogenesis and is suppressed by insulin. To determine the role of FoxO1 in mediating other actions of insulin, we studied mice with hepatic deletion of the insulin receptor, FoxO1, or both. We found that mice with deletion of the insulin receptor alone showed not only hyperglycemia but also a 70% decrease in plasma insulin-like growth factor 1 and delayed growth during the first 2 months of life, a 24-fold increase in the soluble leptin receptor and a 19-fold increase in plasma leptin levels. Deletion of the insulin receptor also produced derangements in fatty acid metabolism, with a decrease in the expression of the lipogenic enzymes, hepatic diglycerides, and plasma triglycerides; in parallel, it increased expression of the fatty acid oxidation enzymes. Mice with deletion of both insulin receptor and FoxO1 showed a much more modest phenotype, with normal or near-normal glucose levels, growth, leptin levels, hepatic diglycerides, and fatty acid oxidation gene expression; however, lipogenic gene expression remained low. Taken together, these data reveal the pervasive role of FoxO1 in mediating the effects of insulin on not only glucose metabolism but also other hormonal signaling pathways and even some aspects of lipid metabolism.

Funding information:
  • NCI NIH HHS - CA157581(United States)
  • NIDDK NIH HHS - R01 DK094162(United States)
  • NIDDK NIH HHS - R01 DK101579(United States)

Male Brown Fat-Specific Double Knockout of IGFIR/IR: Atrophy, Mitochondrial Fission Failure, Impaired Thermogenesis, and Obesity.

  • Viana-Huete V
  • Endocrinology
  • 2018 Jan 1

Literature context:


Abstract:

It is unknown how the lack of insulin receptor (IR)/insulinlike growth factor I receptor (IGFIR) in a tissue-specific manner affects brown fat development and mitochondrial integrity and function, as well as its effect on the redistribution of the adipose organ and the metabolic status. To address this important issue, we developed IR/IGFIR double-knockout (DKO) in a brown adipose tissue-specific manner. Lack of those receptors caused severe brown fat atrophy, enhanced beige cell clusters in inguinal fat; loss of mitochondrial mass; mitochondrial damage related to cristae disruption; and the loss of proteins involved in autophagosome formation, mitophagy, mitochondrial quality control, and dynamics and thermogenesis. More important, DKO mice showed an impaired thermogenesis upon cold exposure, based on a failure in the mitochondrial fission mechanisms and a much lower uncoupling protein 1 transcription rate and content. As a result, DKO mice under normal conditions showed an obesity susceptibility, revealed by increased body fat mass and insulin resistance. Upon consumption of a high-fat diet, DKO mice displayed frank obesity, as shown by increased body weight, increased adiposity, insulin resistance, hyperinsulinemia, and hypertriglyceridemia, all consistent with a metabolic syndrome. Collectively, our data suggest a cause-and-effect relationship between failure in brown fat thermogenesis and increased adiposity and obesity.

Funding information:
  • NIDDK NIH HHS - P30 DK036836()
  • NIDDK NIH HHS - R01 DK031036()

Apolipoprotein E4 Impairs Neuronal Insulin Signaling by Trapping Insulin Receptor in the Endosomes.

  • Zhao N
  • Neuron
  • 2017 Sep 27

Literature context:


Abstract:

Diabetes and impaired brain insulin signaling are linked to the pathogenesis of Alzheimer's disease (AD). The association between diabetes and AD-associated amyloid pathology is stronger among carriers of the apolipoprotein E (APOE) ε4 gene allele, the strongest genetic risk factor for late-onset AD. Here we report that apoE4 impairs neuronal insulin signaling in human apoE-targeted replacement (TR) mice in an age-dependent manner. High-fat diet (HFD) accelerates these effects in apoE4-TR mice at middle age. In primary neurons, apoE4 interacts with insulin receptor and impairs its trafficking by trapping it in the endosomes, leading to impaired insulin signaling and insulin-stimulated mitochondrial respiration and glycolysis. In aging brains, the increased apoE4 aggregation and compromised endosomal function further exacerbate the inhibitory effects of apoE4 on insulin signaling and related functions. Together, our study provides novel mechanistic insights into the pathogenic mechanisms of apoE4 and insulin resistance in AD.

Funding information:
  • NIA NIH HHS - P50 AG016574()
  • NIA NIH HHS - R01 AG027924()
  • NIA NIH HHS - R01 AG035355()
  • NIA NIH HHS - R01 AG046205()
  • NIA NIH HHS - R37 AG027924()
  • NIA NIH HHS - RF1 AG051504()

A Hypothalamic Phosphatase Switch Coordinates Energy Expenditure with Feeding.

  • Dodd GT
  • Cell Metab.
  • 2017 Aug 1

Literature context:


Abstract:

Beige adipocytes can interconvert between white and brown-like states and switch between energy storage versus expenditure. Here we report that beige adipocyte plasticity is important for feeding-associated changes in energy expenditure and is coordinated by the hypothalamus and the phosphatase TCPTP. A fasting-induced and glucocorticoid-mediated induction of TCPTP, inhibited insulin signaling in AgRP/NPY neurons, repressed the browning of white fat and decreased energy expenditure. Conversely feeding reduced hypothalamic TCPTP, to increase AgRP/NPY neuronal insulin signaling, white adipose tissue browning and energy expenditure. The feeding-induced repression of hypothalamic TCPTP was defective in obesity. Mice lacking TCPTP in AgRP/NPY neurons were resistant to diet-induced obesity and had increased beige fat activity and energy expenditure. The deletion of hypothalamic TCPTP in obesity restored feeding-induced browning and increased energy expenditure to promote weight loss. Our studies define a hypothalamic switch that coordinates energy expenditure with feeding for the maintenance of energy balance.

Funding information:
  • NEI NIH HHS - R01 EY017097(United States)

The Ubiquitin Ligase CHIP Integrates Proteostasis and Aging by Regulation of Insulin Receptor Turnover.

  • Tawo R
  • Cell
  • 2017 Apr 20

Literature context:


Abstract:

Aging is attended by a progressive decline in protein homeostasis (proteostasis), aggravating the risk for protein aggregation diseases. To understand the coordination between proteome imbalance and longevity, we addressed the mechanistic role of the quality-control ubiquitin ligase CHIP, which is a key regulator of proteostasis. We observed that CHIP deficiency leads to increased levels of the insulin receptor (INSR) and reduced lifespan of worms and flies. The membrane-bound INSR regulates the insulin and IGF1 signaling (IIS) pathway and thereby defines metabolism and aging. INSR is a direct target of CHIP, which triggers receptor monoubiquitylation and endocytic-lysosomal turnover to promote longevity. However, upon proteotoxic stress conditions and during aging, CHIP is recruited toward disposal of misfolded proteins, reducing its capacity to degrade the INSR. Our study indicates a competitive relationship between proteostasis and longevity regulation through CHIP-assisted proteolysis, providing a mechanistic concept for understanding the impact of proteome imbalance on aging.

Dual Role of Insulin in Spexin Regulation: Functional Link Between Food Intake and Spexin Expression in a Fish Model.

  • Ma A
  • Endocrinology
  • 2017 Mar 1

Literature context:


Abstract:

Spexin (SPX), a neuropeptide discovered by the bioinformatics approach, has been recently identified as a satiety factor in a fish model. However, the functional link between feeding and SPX expression as well as the signal transduction for SPX regulation are totally unknown. In this study, we used goldfish as a model to examine the functional role of insulin as a postprandial signal for SPX regulation in bony fish. In goldfish, feeding could elevate plasma levels of glucose, insulin, and SPX with concurrent rises in insulin and SPX messenger RNA (mRNA) expression in the liver. Similar elevation in SPX mRNA level was also observed in the liver and brain areas involved in appetite control in goldfish after intraperitoneal injection of glucose and insulin, respectively. In parallel experiments with goldfish hepatocytes and brain cell culture, insulin signal induced by glucose was shown to exert a dual role in SPX regulation, namely (1) acting as an autocrine/paracrine signal to trigger SPX mRNA expression in the liver and (2) serving as an endocrine signal to induce SPX gene expression in the brain. Apparently, the peripheral (in the liver) and central actions of insulin (in the brain) on SPX gene expression were mediated by insulin receptor (to a lesser extent by insulin-like growth factor I receptor) coupled to mitogen-activated protein kinase kinase 3/6/p38 mitogen-activated protein kinase and phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin but not mitogen-activated protein kinase kinase 1/2/extracellular signal-regulated kinase 1/2 cascades. Our findings indicate that an insulin component inducible by glucose is present in the liver of the fish model and may serve as the postprandial signal linking food intake with SPX expression both in the central as well as at the hepatic level.

Essential Role of IGFIR in the Onset of Male Brown Fat Thermogenic Function: Regulation of Glucose Homeostasis by Differential Organ-Specific Insulin Sensitivity.

  • Viana-Huete V
  • Endocrinology
  • 2016 Aug 17

Literature context:


Abstract:

Brown fat is a thermogenic tissue that generates heat to maintain body temperature in cold environments and dissipate excess energy in response to overfeeding. We have addressed the role of the IGFIR in the brown fat development and function. Mice lacking IGFIR exhibited normal brown adipose tissue/body weight in knockout (KO) vs control mice. However, lack of IGFIR decreased uncoupling protein 1 expression in interscapular brown fat and beige cells in inguinal fat. More importantly, the lack of IGFIR resulted in an impaired cold acclimation. No differences in the total fat volume were found in the KO vs control mice. Epididymal fat showed larger adipocytes but with a lower number of adipocytes in KO vs control mice at age 12 months. In addition, KO mice showed a sustained moderate hyperinsulinemia and hypertriglyceridemia upon time and hepatic insulin insensitivity associated with lipid accumulation, with the outcome of a global insulin resistance. In addition, we found that the expression of uncoupling protein 3 in the skeletal muscle was decreased and its expression was increased in the heart in parallel with the expression of beta-2 adrenergic receptors. Upon nonobesogenic high-fat diet, we found a severe insulin resistance in the liver and in the skeletal muscle, but unchanged insulin sensitivity in the heart. In conclusion, our data suggest that IGFIR it is not an essential growth factor in the brown fat development in the presence of the IR and very high plasma levels of IGF-I, but it is indispensable for full brown fat functionality.

Funding information:
  • NINDS NIH HHS - 5K01NS085071-03(United States)

Diets Containing α-Linolenic (ω3) or Oleic (ω9) Fatty Acids Rescues Obese Mice From Insulin Resistance.

  • Oliveira V
  • Endocrinology
  • 2015 Nov 17

Literature context:


Abstract:

Subclinical systemic inflammation is a hallmark of obesity and insulin resistance. The results obtained from a number of experimental studies suggest that targeting different components of the inflammatory machinery may result in the improvement of the metabolic phenotype. Unsaturated fatty acids exert antiinflammatory activity through several distinct mechanisms. Here, we tested the capacity of ω3 and ω9 fatty acids, directly from their food matrix, to exert antiinflammatory activity through the G protein-coupled receptor (GPR)120 and GPR40 pathways. GPR120 was activated in liver, skeletal muscle, and adipose tissues, reverting inflammation and insulin resistance in obese mice. Part of this action was also mediated by GPR40 on muscle, as a novel mechanism described. Pair-feeding and immunoneutralization experiments reinforced the pivotal role of GPR120 as a mediator in the response to the nutrients. The improvement in insulin sensitivity in the high-fat substituted diets was associated with a marked reduction in tissue inflammation, decreased macrophage infiltration, and increased IL-10 levels. Furthermore, improved glucose homeostasis was accompanied by the reduced expression of hepatic gluconeogenic enzymes and reduced body mass. Thus, our data indicate that GPR120 and GPR40 play a critical role as mediators of the beneficial effects of dietary unsaturated fatty acids in the context of obesity-induced insulin resistance.

Funding information:
  • NIDDK NIH HHS - P30 DK020572(United States)
  • NIDDK NIH HHS - P30 DK090971(United States)

Coenzyme Q10 Prevents Insulin Signaling Dysregulation and Inflammation Prior to Development of Insulin Resistance in Male Offspring of a Rat Model of Poor Maternal Nutrition and Accelerated Postnatal Growth.

  • Tarry-Adkins JL
  • Endocrinology
  • 2015 Oct 19

Literature context:


Abstract:

Low birth weight and rapid postnatal growth increases the risk of developing insulin resistance and type 2 diabetes in later life. However, underlying mechanisms and potential intervention strategies are poorly defined. Here we demonstrate that male Wistar rats exposed to a low-protein diet in utero that had a low birth weight but then underwent postnatal catch-up growth (recuperated offspring) had reductions in the insulin signaling proteins p110-β (13% ± 6% of controls [P < .001]) and insulin receptor substrate-1 (39% ± 10% of controls [P < .05]) in adipose tissue. These changes were not accompanied by any change in expression of the corresponding mRNAs, suggesting posttranscriptional regulation. Recuperated animals displayed evidence of a proinflammatory phenotype of their adipose tissue with increased IL-6 (139% ± 8% [P < .05]) and IL1-β (154% ± 16% [P < .05]) that may contribute to the insulin signaling protein dysregulation. Postweaning dietary supplementation of recuperated animals with coenzyme Q (CoQ10) (1 mg/kg of body weight per day) prevented the programmed reduction in insulin receptor substrate-1 and p110-β and the programmed increased in IL-6. These findings suggest that postweaning CoQ10 supplementation has antiinflammatory properties and can prevent programmed changes in insulin-signaling protein expression. We conclude that CoQ10 supplementation represents an attractive intervention strategy to prevent the development of insulin resistance that results from suboptimal in utero nutrition.

Funding information:
  • NINDS NIH HHS - NS080889(United States)

Role of VGF-derived carboxy-terminal peptides in energy balance and reproduction: analysis of "humanized" knockin mice expressing full-length or truncated VGF.

  • Sadahiro M
  • Endocrinology
  • 2015 May 18

Literature context:


Abstract:

Targeted deletion of VGF, a secreted neuronal and endocrine peptide precursor, produces lean, hypermetabolic, and infertile mice that are resistant to diet-, lesion-, and genetically-induced obesity and diabetes. Previous studies suggest that VGF controls energy expenditure (EE), fat storage, and lipolysis, whereas VGF C-terminal peptides also regulate reproductive behavior and glucose homeostasis. To assess the functional equivalence of human VGF(1-615) (hVGF) and mouse VGF(1-617) (mVGF), and to elucidate the function of the VGF C-terminal region in the regulation of energy balance and susceptibility to obesity, we generated humanized VGF knockin mouse models expressing full-length hVGF or a C-terminally deleted human VGF(1-524) (hSNP), encoded by a single nucleotide polymorphism (rs35400704). We show that homozygous male and female hVGF and hSNP mice are fertile. hVGF female mice had significantly increased body weight compared with wild-type mice, whereas hSNP mice have reduced adiposity, increased activity- and nonactivity-related EE, and improved glucose tolerance, indicating that VGF C-terminal peptides are not required for reproductive function, but 1 or more specific VGF C-terminal peptides are likely to be critical regulators of EE. Taken together, our results suggest that human and mouse VGF proteins are largely functionally conserved but that species-specific differences in VGF peptide function, perhaps a result of known differences in receptor binding affinity, likely alter the metabolic phenotype of hVGF compared with mVGF mice, and in hSNP mice in which several C-terminal VGF peptides are ablated, result in significantly increased activity- and nonactivity-related EE.

Funding information:
  • NINDS NIH HHS - N01NS02331(United States)

Hypoxia inhibits Cavin-1 and Cavin-2 expression and down-regulates caveolae in adipocytes.

  • Regazzetti C
  • Endocrinology
  • 2015 Mar 21

Literature context:


Abstract:

During obesity, a hypoxic state develops within the adipose tissue, resulting in insulin resistance. To understand the underlying mechanism, we analyzed the involvement of caveolae because they play a crucial role in the activation of insulin receptors. In the present study, we demonstrate that in 3T3-L1 adipocytes, hypoxia induces the disappearance of caveolae and inhibits the expression of Cavin-1 and Cavin-2, two proteins necessary for the formation of caveolae. In mice, hypoxia induced by the ligature of the spermatic artery results in the decrease of cavin-1 and cavin-2 expression in the epididymal adipose tissue. Down-regulation of the expression of cavins in response to hypoxia is dependent on hypoxia-inducible factor-1. Indeed, the inhibition of hypoxia-inducible factor-1 restores the expression of cavins and caveolae formation. Expression of cavins regulates insulin signaling because the silencing of cavin-1 and cavin-2 impairs insulin signaling pathway. In human, cavin-1 and cavin-2 are decreased in the sc adipose tissue of obese diabetic patients compared with lean subjects. Moreover, the expression of cavin-2 correlates negatively with the homeostatic model assessment index of insulin resistance and glycated hemoglobin level. In conclusion, we propose a new mechanism in which hypoxia inhibits cavin-1 and cavin-2 expression, resulting in the disappearance of caveolae. This leads to the inhibition of insulin signaling and the establishment of insulin resistance.

Funding information:
  • NIDA NIH HHS - R21 DA034195(United States)

Effects of the antitumor drug OSI-906, a dual inhibitor of IGF-1 receptor and insulin receptor, on the glycemic control, β-cell functions, and β-cell proliferation in male mice.

  • Shirakawa J
  • Endocrinology
  • 2014 Jun 19

Literature context:


Abstract:

The IGF-1 receptor has become a therapeutic target for the treatment of cancer. The efficacy of OSI-906 (linstinib), a dual inhibitor of IGF-1 receptor and insulin receptor, for solid cancers has been examined in clinical trials. The effects of OSI-906, however, on the blood glucose levels and pancreatic β-cell functions have not yet been reported. We investigated the impact of OSI-906 on glycemic control, insulin secretion, β-cell mass, and β-cell proliferation in male mice. Oral administration of OSI-906 worsened glucose tolerance in a dose-dependent manner in the wild-type mice. OSI-906 at a dose equivalent to the clinical daily dose (7.5 mg/kg) transiently evoked glucose intolerance and hyperinsulinemia. Insulin receptor substrate (IRS)-2-deficient mice and mice with diet-induced obesity, both models of peripheral insulin resistance, exhibited more severe glucose intolerance after OSI-906 administration than glucokinase-haploinsufficient mice, a model of impaired insulin secretion. Phloridzin improved the hyperglycemia induced by OSI-906 in mice. In vitro, OSI-906 showed no effect on insulin secretion from isolated islets. After daily administration of OSI-906 for a week to mice, the β-cell mass and β-cell proliferation rate were significantly increased. The insulin signals in the β-cells were apparently unaffected in those mice. Taken together, the results suggest that OSI-906 could exacerbate diabetes, especially in patients with insulin resistance. On the other hand, the results suggest that the β-cell mass may expand in response to chemotherapy with this drug.

Funding information:
  • NIEHS NIH HHS - R01ES015145(United States)
  • NINDS NIH HHS - NS072202(United States)

Metformin inhibits androgen-induced IGF-IR up-regulation in prostate cancer cells by disrupting membrane-initiated androgen signaling.

  • Malaguarnera R
  • Endocrinology
  • 2014 Apr 24

Literature context:


Abstract:

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.

Funding information:
  • Intramural NIH HHS - ZIA ES102805(United States)