Regulation of type 1 insulin-like growth factor (IGF) receptors and IGF-I mRNA by age and nutrition in ovine skeletal muscles

1996 ◽  
Vol 148 (2) ◽  
pp. 337-346 ◽  
Author(s):  
J M Oldham ◽  
J A K Martyn ◽  
S P Kirk ◽  
J R Napier ◽  
J J Bass
Keyword(s):  
Connective Tissue ◽  
Muscle Fibre ◽  
Relative Abundance ◽  
Specific Binding ◽  
Biceps Femoris ◽  
Competitive Binding Assay ◽  
Igf Receptors ◽  
Igf I

Abstract The relative abundance and location of type 1 IGF receptors in sheep muscles have been measured to determine whether changes occur during post-natal growth and nutritional stress. Using the technique of histological autoradiography, specific binding of 125I-IGF-I in muscle fibre and connective tissue of M. biceps femoris and M. gastrocnemius was demonstrated, as was specific binding to the tendon of M. gastrocnemius and the surrounding connective tissue. The binding site in both muscles was characterised as the type 1 IGF receptor in membrane preparations using competitive binding assay and SDS-PAGE. Type 1 receptors were more abundant in connective tissue than muscle fibre or tendon (P≤0·001). Levels changed significantly with age in all tissues (P=0·054 to P≤ 0·001), while change as a result of fasting was limited to a receptor increase in the connective tissue of M. gastrocnemius (P=0·034). IGF-I mRNA in M. bicepsfemoris, as assessed by in situ hybridisation, showed changes in expression with increasing age (P≤ 0·025) but no change with fasting. These data indicate that the distribution, relative abundance and nutritional sensitivity of type 1 receptors are related to cell type in vivo. The overall decline of receptors with increasing age may be a feature of transition from linear animal growth to cell maintenance in adult animals. Connective tissue appears to be more sensitive than muscle fibre to nutrition, possibly allowing the reduction of non-essential metabolism during fasting. Journal of Endocrinology (1996) 148, 337–346

scholarly journals Tumor Uptake of Triazine Dendrimers Decorated with Four, Sixteen, and Sixty-Four PSMA-Targeted Ligands: Passive versus Active Tumor Targeting

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 421 ◽  
Author(s):  
Jongdoo Lim ◽  
Bing Guan ◽  
Kien Nham ◽  
Guiyang Hao ◽  
Xiankai Sun ◽  
...  
Keyword(s):  
Specific Binding ◽  
Quantitative Imaging ◽  
Molecular Size ◽  
Tumor Uptake ◽  
Competitive Binding Assay ◽  
The Core ◽  
Positron Emission ◽  
Pentanedioic Acid

Various glutamate urea ligands have displayed high affinities to prostate specific membrane antigen (PSMA), which is highly overexpressed in prostate and other cancer sites. The multivalent versions of small PSMA-targeted molecules are known to be even more efficiently bound to the receptor. Here, we employ a well-known urea-based ligand, 2-[3-(1,3-dicarboxypropyl)-ureido] pentanedioic acid (DUPA) and triazine dendrimers in order to study the effect of molecular size on multivalent targeting in prostate cancer. The synthetic route starts with the preparation of a dichlorotriazine bearing DUPA in 67% overall yield over five steps. This dichlorotriazine reacts with G1, G3, and G5 triazine dendrimers bearing a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) group for 64Cu-labeling at the core to afford poly(monochlorotriazine) intermediates. Addition of 4-aminomethylpiperidine (4-AMP) and the following deprotection produce the target compounds, G1-(DUPA)4, G3-(DUPA)16, and G5-(DUPA)64. These targets include 4/16/64 DUPA groups on the surface and a DOTA group at the core, respectively. In vitro cell assay using PC3-PIP (PSMA positive) and PC3-FLU (PSMA negative) cells reveals that G1-(DUPA)4 has the highest PC3-PIP to PC3-FLU uptake ratio (10-fold) through the PSMA-mediated specific uptake. While G5-(DUPA)64 displayed approximately 12 times higher binding affinity (IC50 23.6 nM) to PC3-PIP cells than G1-(DUPA)4 (IC50 282.3 nM) as evaluated in a competitive binding assay, the G5 dendrimer also showed high non-specific binding to PC3-FLU cells. In vivo uptake of the 64Cu-labeled dendrimers was also evaluated in severe combined inmmunodeficient (SCID) mice bearing PC3-PIP and PC3-FLU xenografts on each shoulder, respectively. Interestingly, quantitative imaging analysis of positron emission tomograph (PET) displayed the lowest tumor uptake in PC3-PIP cells for the midsize dendrimer G3-(DUPA)16 (19.4 kDa) (0.66 ± 0.15%ID/g at 1 h. p.i., 0.64 ± 0.11%ID/g at 4 h. p.i., and 0.67 ± 0.08%ID/g at 24 h. p.i.). Through the specific binding of G1-(DUPA)4 to PSMA, the smallest dendrimer (5.1 kDa) demonstrated the highest PC3-PIP to muscle and PC3-PIP to PC3-FLU uptake ratios (17.7 ± 5.5 and 6.7 ± 3.0 at 4 h p.i., respectively). In addition, the enhanced permeability and retention (EPR) effect appeared to be an overwhelming factor for tumor uptake of the largest dendrimer G5-(DUPA)64 as the uptake was at a similar level irrelevant to the PSMA expression.

Insulin-like growth factors and the multiplication of Tera-2, a human teratoma-derived cell line

1988 ◽  
Vol 90 (3) ◽  
pp. 475-484
Author(s):  
C. Biddle ◽  
C.H. Li ◽  
P.N. Schofield ◽  
V.E. Tate ◽  
B. Hopkins ◽  
...  
Keyword(s):  
Growth Factors ◽  
Cell Line ◽  
Serum Free Medium ◽  
Free Medium ◽  
Maximal Stimulation ◽  
Igf Receptors ◽  
Igf I ◽  
Insulin Like Growth Factors

A human teratoma cell line (Tera-2) was grown in serum-free medium, and the population multiplication was stimulated by the addition of somatomedins/insulin-like growth factors (IGFs). Both IGF-I and IGF-II gave maximal stimulation when added daily at 10 ng ml-1. The IGFs did not substantially change the labelling index of the cells, and the IGFs appeared to exert their effect on population multiplication by increasing cell survival. Membranes isolated from Tera-2 cells displayed both type 1 and type 2 IGF receptors.

scholarly journals Nutritional dependence of insulin-like growth factor (IGF) receptors in skeletal muscle: measurement by light microscopic autoradiography.

1993 ◽  
Vol 41 (3) ◽  
pp. 415-421 ◽  
Author(s):  
J M Oldham ◽  
A K Hodges ◽  
P N Schaare ◽  
P C Molan ◽  
J J Bass
Keyword(s):  
Skeletal Muscle ◽  
Growth Factor ◽  
Connective Tissue ◽  
Blood Vessels ◽  
Muscle Fiber ◽  
Insulin Like Growth Factor ◽  
Igf Receptors

To determine the cellular location, capacity, and nutritional sensitivity of insulin-like growth factor (IGF) receptors, we measured the in vitro binding of [125I]-IGFs to skeletal muscle using light microscopic autoradiography. Muscle was collected from 8-month lambs that had received high or low nutrition diets (3% and 1.25% of body weight/day in pellets, respectively). Half of each group had also received growth hormone (0.25 mg/kg/day). Cryosections were incubated with [125I]-IGF alone or with unlabeled IGF-1, IGF-2, or insulin to characterize binding sites as probable Type 1 IGF, Type 2 IGF, or insulin receptors. [125I]-IGF-1 was found to bind to blood vessels and Type 1 receptors in connective tissue (p < or = 0.001), but not to muscle fiber or nerves. In muscle from 6-month lambs that were fed or fasted, [125I]-IGF-1 bound to Type 1 receptors in connective tissue (p < or = 0.01 fed; p < or = 0.05 fasted) and muscle fiber (p < or = 0.05). The binding to connective tissue was also greater in fasted than in fed animals (p < or = 0.05). Binding of [125I]-IGF-2 to the Type 2 receptor was located in blood vessels and connective tissue (p < or = 0.01) and did not alter with fasting. Therefore, these experiments have demonstrated that Type 1 and Type 2 receptors vary in their distribution and nutritional sensitivity in skeletal muscle.

scholarly journals Autocrine role of IGF-II in proliferation of human adrenocortical carcinoma NCI H295R cell line

1999 ◽  
Vol 23 (1) ◽  
pp. 23-32 ◽  
Author(s):  
A Logie ◽  
N Boulle ◽  
V Gaston ◽  
L Perin ◽  
P Boudou ◽  
...  
Keyword(s):  
Cell Line ◽  
In Vitro Model ◽  
Igf System ◽  
Igf Receptors ◽  
Igf I ◽  
H295r Cells ◽  
Igf Receptor ◽  
Vitro Model

In adrenocortical tumors, the malignant phenotype is associated with rearrangements (paternal isodisomy) at the 11p15 locus and IGF-II gene overexpression, strongly suggesting that the IGF system is a major determinant of adrenocortical tumor progression. The aim of this study was to validate an in vitro model for investigating the involvement of the IGF system in adrenocortical tumorigenesis. We analyzed the production of IGF mRNA and proteins, IGF-binding proteins (IGFBPs) and IGF receptors by the NCI H295R cell line, which is derived from a human adult adrenocortical carcinoma. H295R cells were shown to proliferate for a long period (26 days) in the absence of serum or any added growth factor. Northern blot analyses showed high IGF-II mRNA contents in H295R cells. The cells secreted large amounts of IGF-II protein (14 ng/10(6) cells per 48 h) although no IGF-I protein was detected. Western ligand blot analyses of conditioned media detected the presence of large amounts of a 34 kDa protein, which was identified as IGFBP-2 by immunoblotting. The presence of high-affinity binding sites for IGF-I and IGF-II on H295R cells was shown by binding experiments using radiolabeled IGFs and confirmed by reverse transcription PCR analyses showing type 1 and type 2 IGF receptors. Proliferation of H295R cells was inhibited by anti-IGF-II antibody (45%) and by anti-type 1 IGF receptor antibody (53%) indicating that IGF-II is an autocrine growth factor for these cells and that its effects are, at least in part, mediated by the type 1 IGF receptor. These findings confirm the involvement of the IGF system in adrenocortical tumors and suggest that the H295R cell line is a suitable in vitro model for studying the molecular mechanisms of adrenocortical tumor proliferation.

Insulin-like growth factor I receptors are more abundant than insulin receptors in human micro- and macrovascular endothelial cells

2004 ◽  
Vol 286 (6) ◽  
pp. E896-E901 ◽  
Author(s):  
Simona I. Chisalita ◽  
Hans J. Arnqvist
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Dna Synthesis ◽  
Specific Binding ◽  
Insulin Receptors ◽  
Receptor Protein ◽  
Β Subunit ◽  
Igf I ◽  
Long Acting

Micro- and macroangiopathy are major causes of morbidity and mortality in patients with diabetes. Our aim was to characterize IGF-I receptor (IGF-IR) and insulin receptor (IR) in human micro- and macrovascular endothelial cells. Cultured human dermal microvascular endothelial cells (HMVEC) and human aortic endothelial cells (HAEC) were used. Gene expression was measured by quantitative real-time RT-PCR and receptor protein by ligand-binding assay. Phosphorylation of IGF-IR β-subunit was analyzed by immunoprecipitation and Western blot. Glucose metabolism and DNA synthesis was assessed using [3H]glucose and [3H]thymidine incorporation, respectively. We detected gene expression of IGF-IR and IR in HAEC and HMVEC. IGF-IR gene expression was severalfold higher than that of IR. The specific binding of 125I-IGF-I was higher than that of 125I-insulin in HAEC and HMVEC. Insulin and the new, long-acting insulin analog glargine interacted with the IGF-IR with thousand- and hundred-fold less potency than IGF-I itself. Phosphorylation of the IGF-IR β-subunit was shown in HAEC for IGF-I (10−8 M) and insulin (10−6 M) and in HMVEC for IGF-I and glargine (10−8 M, 10−6 M). IGF-I 10−7 M stimulated incorporation of [3H]thymidine into DNA, and 10−9–10−7 M also the incorporation of [3H]glucose in HMVEC, whereas glargine and insulin had no significant effects at 10−9–10−7 M. Human micro- and macrovascular endothelial cells express more IGF-IR than IR. IGF-I and high concentrations of glargine and insulin activates the IGF-IR. Glargine has a higher affinity than insulin for the IGF-IR but probably has no effect on DNA synthesis at concentrations reached in vivo.

Insulin-like growth factor axis in airway smooth muscle cells

1994 ◽  
Vol 267 (6) ◽  
pp. L761-L765 ◽  
Author(s):  
J. P. Noveral ◽  
A. Bhala ◽  
R. L. Hintz ◽  
M. M. Grunstein ◽  
P. Cohen
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Airway Smooth Muscle Cells ◽  
Igf Binding Proteins ◽  
Cell Proliferation And Differentiation ◽  
Igf Receptors ◽  
Igf I ◽  
Igf Receptor ◽  
Mediate Cell

Insulin-like growth factors (IGFs) mediate cell proliferation and differentiation and bind with high affinities and specificities to IGF receptors and IGF-binding proteins (IGFBPs). We examined the roles of these three groups of proteins in cultured rabbit airway smooth muscle (ASM) cells. Affinity cross-linking of IGF-I and IGF-II to membranes of ASM cells revealed type 1 and type 2 IGF receptors. Western ligand blot analysis of ASM cell-conditioned medium revealed the presence of a single IGFBP band that precipitated with an antibody specific to IGFBP-2. ASM cells secreted radioimmunoassayable IGF-II; however, no IGF-I was detected under the same conditions. Two molecular weight forms of IGF-II were produced by the ASM cells. Exposure of cells to 1,000 ng/ml of IGF-I stimulated them to proliferate to 230 +/- 9.7% of their respective controls. Exposure to 1,000 ng/ml of IGF-II was approximately 40% as effective as exposure to 1,000 ng/ml of IGF-I. Both IGF-I and IGF-II exhibited binding to the type 1 IGF receptor. In summary, IGFs are mitogens for cultured rabbit ASM cells, and their actions are most likely mediated through the type 1 IGF receptor. The ASM cells secrete IGF-II and IGFBP-2, and the latter could modulate the actions of the IGFs in these cells.

scholarly journals Purification, amino acid sequence and characterisation of kangaroo IGF-I

1998 ◽  
Vol 156 (1) ◽  
pp. 195-204 ◽  
Author(s):  
CA Yandell ◽  
GL Francis ◽  
JF Wheldrake ◽  
Z Upton
Keyword(s):  
Amino Acid ◽  
Protein Sequencing ◽  
Lung Fibroblasts ◽  
Terminal Protein ◽  
Factor I ◽  
Sminthopsis Crassicaudata ◽  
Igf Receptors ◽  
Igf I

Insulin-like growth factor-I (IGF-I) and IGF-II have been purified to homogeneity from kangaroo (Macropus fuliginosus) serum, thus this represents the first report of the purification, sequencing and characterisation of marsupial IGFs. N-Terminal protein sequencing reveals that there are six amino acid differences between kangaroo and human IGF-I. Kangaroo IGF-II has been partially sequenced and no differences were found between human and kangaroo IGF-II in the 53 residues identified. Thus the IGFs appear to be remarkably structurally conserved during mammalian radiation. In addition, in vitro characterisation of kangaroo IGF-I demonstrated that the functional properties of human, kangaroo and chicken IGF-I are very similar. In an assay measuring the ability of the proteins to stimulate protein synthesis in rat L6 myoblasts, all IGF-I proteins were found to be equally potent. The ability of all three proteins to compete for binding with radiolabelled human IGF-I to type-1 IGF receptors in L6 myoblasts and in Sminthopsis crassicaudata transformed lung fibroblasts, a marsupial cell line, was comparable. Furthermore, kangaroo and human IGF-I react equally in a human IGF-I RIA using a human reference standard, radiolabelled human IGF-I and a polyclonal antibody raised against recombinant human IGF-I. This study indicates that not only is the primary structure of eutherian and metatherian IGF-I conserved, but also the proteins appear to be functionally similar.

Characterization of serum-derived and recombinant rat IGF-I and their use for measuring true concentrations of IGF-I in rat plasma

1996 ◽  
Vol 149 (3) ◽  
pp. 379-387 ◽  
Author(s):  
Z Upton ◽  
H Webb ◽  
F M Tomas ◽  
F J Ballard ◽  
G L Francis
Keyword(s):  
Rat Plasma ◽  
Reference Standards ◽  
Igf Binding Proteins ◽  
Igf I ◽  
Igf Binding ◽  
Igf Receptor

Abstract While numerous researchers have used rat models to investigate the in vivo actions of IGF-I, interpretation of the results in terms of true concentrations of rat IGF-I (rIGF-I) in plasma has been hampered by the absence of homologous reference standards. In order to overcome this we have produced recombinant rIGF-I (rrIGF-I) from Escherichia coli using procedures similar to those we have previously described for the production of other recombinant IGFs. The rrIGF-I is indistinguishable from serum-derived rIGF-I when characterized in a number of in vitro assays including ability to stimulate protein synthesis and inhibit protein degradation in cultured rat cells, as well as in interactions with the rat type-1 IGF receptor and with rat IGF-binding proteins. Moreover, both the serum-derived and the recombinant rat proteins are similar to recombinant human IGF-I (rhIGF-I) in these assays. However, differences between the human and rat IGFs are apparent when tested in immunoassays using some antibodies raised against rhIGF-I. Furthermore, the differences between rhIGF-I and rrIGF-I are even greater when rhIGF-I is used as the competing radiolabel in these assays, a situation that can lead to a two- to threefold underestimation of the actual concentration of IGF-I in rat plasma. These results indicate that, while immunoassays employing antibodies raised against rhIGF-I and rhIGF-I reference standards reliably indicate trends in IGF-I concentrations in rat plasma, the true amounts of rIGF-I present can only be assured in an assay using homologous tracer and reference peptides. Journal of Endocrinology (1996) 149, 379–387

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