Association of insulin-like growth factor-binding protein-3 with radiotherapy response and prognosis of esophageal squamous cell carcinoma

Background: Insulin?like growth factor?binding protein?3(IGFBP?3) is suggested to predict the radiosensitivity and/or prognosis of patients with esophageal squamous cell carcinoma(ESCC). The present study was designed to investi?gate the clinical and prognostic efects of IGFBP?3 on ESCC.Methods: IGFBP?3 was detected by immunohistochemistry in parain?embedded tissues from 70 ESCC patients treated with radiotherapy alone and further examined by western blotting analysis in 10 pairs of fresh ESCC tissues and adjacent non?malignant esophageal specimens. Receiver operating characteristic(ROC) analysis was used to determine cut?of scores for tumor positivity and to evaluate patient survival status. The χ2 test was performed to analyze the association of IGFBP?3 expression with clinical characteristics and radiotherapy response. Associations between prognostic outcomes and IGFBP?3 expression were investigated using Kaplan–Meier analysis and the Cox proportional hazards model.Results: The threshold for IGFBP?3 positivity was set to greater than 65% [area under the ROC curve(AUC)(45.7%) were deined as having high IGFBP?3 expression= 0.690, P < 0.019]. Of the 70 ESCC patient tissues tested, 32. The levels of IGFBP?3 protein expression were decreased in 70.0%(7 of 10) of ESCC tissues compared with adjacent non?malignant esophageal tissue. In addition, IGFBP?3 expression was associated with pathologic classiication(P < 0.05 for T, N, and M categories and clinical stage). Patients with elevated protein level of IGFBP?3 in the tumor had an improved radiotherapy response and prolonged overall survival(P < 0.001).Conclusions: High level of IGFBP?3 expression in ESCC associates with early clinical stages and are predictive for favorable survival of the patients treated with radiotherapy.

Increased expression of insulin-like growth factor-binding protein-3 is implicated in erectile dysfunction in two-kidney one-clip hypertensive rats after propranolol treatment

This study aimed to investigate the role of insulin-like growth factor-binding protein-3 （IGFBP-3） in erectUe dysfunction （ED） in two-kidney one-clip （2K-1C） hypertensive rats treated with the β-blocking agent propranolol. Adult male Wistar rats were randomly divided into three groups： a normal control group, a hypertensive control group and a propranolol treatment group （n=9）. After 4 weeks of propranolol treatment, intracavemous pressure （ICP） responses to electrical stimulation of the cavernous nerves were evaluated. The expression of IGFBP-3 and insulin-like growth factor-1 （IGF-1） mRNA and protein in the rat cavernous tissue were detected by quantitative real-time PCR and Western blot, respectively. The concentration of cyclic guanosine monophosphate （cGMP） in the cavernous tissue was determined by enzyme-linked immunosorbent assay （ELISA）. Cavernosal pressure in response to cavernous nerve stimulation was decreased 4 weeks after propranolol treatment （P〈0.01, compared to the hypertensive control group）. IGFBP-3 mRNA and protein expression was increased in the propranolol treatment group compared to the hypertensive control group （P〈O.01）, whereas IGF-1 expression was decreased in the propranolol treatment group compared to the hypertensive control group （P〈0.01）. In addition, cavernous cGMP concentration was decreased in the prepranolol treatment group compared to the hypertensive control group （P〈0.01）. Taken together, these results suggest that the upregulation of IGFBP-3 may play a role in the development of ED in hypertensive rats.

Insulin-like growth factor-binding protein-3 inhibits IGF-1-induced proliferation of human hepatocellular carcinoma cells

OBJECTIVE Basic fibroblast growth factor(b FGF)and platelet-derived growth factor(PDGF)produced by hepatocellular carcinoma(HCC)cells are responsible for the cell growth.Accumulating evidence shows that insulin-like growth factor-binding protein-3(IGFBP-3)suppresses HCC cell proliferation in both IGF-dependent and independent manners.The present study is to investigate whether treatment with exogenous IGFBP-3 inhibits bF GF and PDGF production and the cell proliferation of HCC cells.METHODS Cell Counting Kit 8 assay were designed to detect HCC cell proliferation,transcription factor early growth response-1(EGR1)involving in IGFBP-3 regulation of b FGF and PDGF were detected by RT-PCR and Western blot assays.Western blot assay was adopted to detect the IGFBP-3 regulating insulin-like growth factor 1 receptor(IGF-1R)signaling pathway.RESULTS The present study demonstrates that IGFBP-3 suppressed IGF-1-induced b FGF and PDGF expression while it does not affect their expression in the absence of IGF-1.To delineate the underlying mechanism,Western-blot and RT-PCR assays confirmed that the transcription factor early growth response protein 1(EGR1)is involved in IGFBP-3 regulation of b FGF and PDGF.IGFBP-3 inhibition of type 1 insulin-like growth factor receptor(IGF1R),ERK and AKT activation is IGF-1-dependent.Furthermore,transient transfection with constitutively activated AKT or MEK partially blocks the IGFBP-3 inhibition of EGR1,b FGF and PDGF expression.CONCLUSION In conclusion,these findings suggest that IGFBP-3suppresses transcription of EGR1 and its target genes b FGF and PDGF through inhibiting IGF-1-dependent ERK and AKT activation.It demonstrates the importance of IGFBP-3 in the regulation of HCC cell proliferation,suggesting that IGFBP-3 could be a target for the treatment of HCC.

A peptide containing the receptor binding site of insulin-like growth factor binding protein-2 enhances bone mass in ovariectomized rats

Male Igfbp2-/-mice have a significant reduction in bone mass and administration of a peptide that contains the insulin-like growth factor binding protein-2(IGFBP-2) receptor-binding domain stimulates bone formation in these animals. Female Igfbp2-/-mice do not have this phenotype but following ovariectomy(OVX) lose more bone than OVX wild-type mice. This suggests that in the absence of estrogen, IGFBP-2 is required to maintain bone mass. Therefore these studies were undertaken to determine if this peptide could stimulate bone acquisition in OVX rats. OVX rats were divided into seven treatment groups: sham animals, OVX animals, OVX animals receiving a control scrambled peptide, or one of three doses of the active peptide termed PEG-HBD-1(0.7, 2,and 6 mg·kg^(-1)) and an OVX group receiving parathyroid hormone(PTH)(50 μg·kg-1 per day). The peptides were administered for8 weeks. DXA revealed a significant reduction in femoral and tibial areal bone mineral density(aBMD) after OVX, whereas treatment with the high-dose peptide increased aBMD by 6.2% ± 2.4%(P < 0.01) compared to control peptide; similar to the increase noted with PTH(5.6% ± 3.0%, P < 0.01). Similar increases were noted with two lower doses of the peptide(3.8% ± 1.5%, P < 0.05 for low dose; 3.1% ± 1.6%, P = 0.07 for middle dose). Micro CT showed that the OVX control peptide animals had reductions of 41% and64% in femoral trabecular BV/TV and trabecular number, respectively. All three doses of the peptide increased bone volume/total volume(BV/TV) significantly, while the low and middle doses increased trabecular number. Cortical BV/TV and thickness at the midshaft increased significantly with each dose of peptide(18.9% ± 9.8%, P < 0.01 and 14.2% ± 7.9%, P < 0.01 for low dose; 23.7% ±10.7%, P < 0.001 and 15.8% ± 6.1%, P < 0.001 for middle dose; 19.0% ± 6.9%, P < 0.01 and 16.2% ± 9.7%, P < 0.001 for high dose)and with PTH(25.8% ± 9.2%, P < 0.001 and 19.4% ± 8.8%, P < 0.001). Histomorphometry showed that the lowest dose of peptide stimulated BV/TV, trabecular thickness, mineral apposition rate(MAR), bone formation rate/bone surface(BFR/BS), number of osteoblasts/bone perimeter(N.ob/B.pm), and decreased osteoclast surface/bone perimeter(Oc.S/B.Pm). The highest dose stimulated each of these parameters except MAR and BFR/BS. Thus, the heparin-binding domain receptor region of IGFBP-2 accounts for its anabolic activity in bone. Importantly, this peptide enhances bone mass in estrogen-deficient animals.

Insulin-like growth factor binding protein-7 induces activation and transdifferentiation of hepatic stellate cells in vitro

AIM:To investigate the role of insulin-like growth factor binding protein-7 (IGFBP-7) in the activation and transdifferentiation of hepatic stellate cells (HSC) in vitro.METHODS:Rat HSC-T6 cells were cultured in separate dishes and treated with various concentration of transforming growth factor (TGF)-β1,IGFBP-7 or antiIGFBP-7 antibody for 24 h.The supernatant or a cytoplasm suspension was obtained from cultured HSC,followed by transfer of cells to form cell-coated dishes.Immunocytochemistry and Western blotting were used to analyze the expression of IGFBP-7 induced by TGF-β1 and the level of fibronectin,collagen and α-smooth muscle actin (SMA).The pro-apoptotic effect of antiIGFBP-7 antibody was determined by flow cytometry.RESULTS:Immunocytochemistry and Western blotting revealed that the expression of IGFBP-7 in TGF-β1 treated HSC was significantly up-regulated compared to that in the control group.In addition,fibronectin,collagen and α-SMA also showed enhanced expression in accordance with the transdifferentiation process in a dose-dependent manner to some extent.Moreover,flow cytometry suggested that anti-IGFBP-7 antibody induced apoptosis of activated HSC,which is responsible for the development of liver fibrosis,and may represent a novel pathway and target for therapeutic intervention.CONCLUSION:IGFBP-7 showed increased expression in activated HSC and played an important role in the activation and transdifferentiation process of HSC.AntiIGFBP-7 antibody may ameliorate liver fibrogenesis.

Serum measurements of testosterone, insulin-like growth factor 1, and insulin-like growth factor binding protein-3 in the diagnosis of prostate cancer among Korean men

Aim： To investigate the relationships of serum testosterone, insulin-like growth factor （IGF）- 1 and IGF-binding protein （IGFBP）-3 levels with prostate cancer risk and also with known prognostic parameters of prostate cancer in Korean men who received radical retropubic prostatectomy （RRP） for clinically-localized prostate cancer. Methods： Serum levels of total testosterone, free testosterone, IGF-1 and IGFBP-3 were determined in 592 patients who subsequently received prostate biopsy. Results were compared between patients who eventually received RRP for prostate cancer （n = 159） and those who were not diagnosed with prostate cancer from biopsy （control group, n = 433）. Among the prostate cancer only patients, serum hormonal levels obtained were analyzed in relation to serum prostate specific antigen （PSA）, pathological T stage and pathological Gleason score. Results： Prostate cancer patients and the control group demon- strated no significant differences regarding serum levels of total testosterone, free testosterone, IGF-I and IGFBP-3 across the different age groups. Among the cancer only patients, no significant associations were observed for serum levels of total testosterone, free testosterone, IGF-1 and IGFBP-3 levels with pathological T stage, pathological Oleason score and preoperative PSA. Conclusion： Our data indicate that simple quantifications of serum testosterone and IGF-1 along with IGFBP-3 levels might not provide useful clinical information in the diagnosis of clinically localized prostate cancer in Korean men. Also, our results suggest that serum levels of testosterone, IGF-1 and IGFBP-3 might not be significantly associated with known prognostic factors of clinically localized prostate cancer in Korean men. （Asian J Androl 2008 Mar; 10： 207-213）

Cloning and Sequence Analysis of IGFBP-7 Gene in Sheep

In this study, full-length CDS sequence of IGFBP-7 gene was cloned from Liangshan semi-fine wool sheep with RT-PCR method and analyzed with bioinformatics methods. The results showed that the full-length CDS sequence of IGFBP-7 gene in Liangshan semi-fine wool sheep was 846 bp in length, encoding 282 amino acids. The CDS sequence shared 99%, 95% and 90% homology with bovine, human and rat, respectively; the amino acid sequence shared 98%, 93% and 89%, respectively. The GenBank accession number was FJ589640.1. The amino acid molecular weight of IGFBP-7 was 29.0 kD, and the theoretical isoelec- tric point （pl） was 8.25. The result of phylogenetic analysis showed that IGFBP-7 gone in Liangshan semi-fine wool sheep exhibited close phylogenetic relationships with bovine, goat and other mammals, and distant phylogenetic relationships with Danio rerio and Haliotis diversicolor. IGFBP-7 gene had uniformly distributed hy- drophobic and hydrophilic regions, harboring one signal peptide, two transmembrane regions, 16 phosphorylation sites, four N-glycosylation sites and one O-glyco- sylation site. The result of secondary structure analysis showed that the random coil, or-helix and β-sheet regions accounted for 64.89%, 19.86% and 15.25%, respectively. The result of tertiary structure analysis showed that IGFBP-7 harbors an IGFBP_N domain and an Ig-like domain. This study provided scientific basis for further investigating the function of IGFBP-7 gene in sheep.

Cloning and Sequence Analysis of IGFBP-1 Gene in Sheep

In this study, using Liangshan semi-fine wool sheep as an experimental material, full-length CDS sequence of IGFBP-1 gene was cloned with RT-PCR method and analyzed with bioinformatics methods. The results showed that the full-length CDS sequence of IGFBP-1 gene in Liangshan semi-fine wool sheep was 792 bp in length, encoding 263 amino acids. The CDS sequence shared 97%, 76% and 74% homology with bovine, human and rat, respectively; the amino acid sequence shared 97% , 69% and 71%, respectively. The GenBank accession number was FJ589639.1. The amino acid molecular weight of IGFBP-1 was 27.8 kD, and the theoretical isoelectric point （pl） was 5.99. The result of phylogenetic analysis showed that IGFBP-1 gene in Liangshan semi-fine wool sheep exhibited close phylogenetic relationships with bovine, goat and other mammals, and distant phylogenetic relationships with chicken and fish. IGFBP-1 gene had obvious hy- drophobic and hydrophilic regions, harboring one signal peptide, one transmembrane region, 16 phosphorylation sites, six N-glycesylation sites and eight O-glycosy- lation sites. The result of secondary structure analysis showed that the random coil, a-helix and 13-sheet regions accounted for 61.98%, 24.33% and 13.69%, re- spectively. The result of tertiary structure analysis showed that IGFBP-1 harbors an IGFBP_N domain and a thyrnglobulin type-1 domain. This study laid a solid foundation for further investigating the function of IGFBP-1 gene in sheep.