Insulin-like growth factor-1 induces lymphangiogenesis and facilitates lymphatic metastasis in colorectal cancer

AIM:To investigate the expression of insulin-like growth factor-1(IGF-1)/insulin-like growth factor-1 receptor(IGF-1R)in colorectal cancer(CRC)tissues and to analyze their correlation with lymphangiogenesis and lymphatic metastasis.METHODS:Immunohistochemistry was used to evaluate IGF-1 and IGF-1R expression and lymphatic vessel density(LVD)in 40 CRC specimens.The correlation between IGF-1/IGF-1R and LVD was investigated.Effects of IGF-1 on migration and invasion of CRC cells were examined using transwell chamber assays.A LoVo cell xenograft model was established to further detect the role of IGF-1 in CRC lymphangiogenesis in vivo. RESULTS:Elevated IGF-1 and IGF-1R expression in CRC tissues was correlated with lymph node metastasis(r=0.715 and 0.569,respectively,P<0.05)and tumor TNM stage(r=0.731 and 0.609,P<0.05).A higher LVD was also found in CRC tissues and was correlated with lymphatic metastasis(r=0.405,P<0.05).A positive correlation was found between LVD and IGF-1R expression(r=0.437,P<0.05).Transwell assays revealed that IGF-1 increased the migration and invasion of CRC cells.In vivo mouse studies showed that IGF-1 also increased LVD in LoVo cell xenografts.CONCLUSION:IGF-1/IGF-1R signaling induces tumorassociated lymphangiogenesis and contributes to lymphatic metastasis of CRC.

Improvement in erectile dysfunction after insulin-like growth factor-1 gene therapy in diabetic rats

Aim： To determine whether adenoviral gene transfer of insulin like growth factor-1 （IGF-1） to the penis of streptozotocin （STZ）-induced diabetic rats could improve erectile capacity. Methods： The STZ diabetic rats were transfected with AdCMV-βgal or AdCMV-IGF-1. These rats underwent cavernous nerve stimulation to assess erectile function and their responses were compared with those of age-matched control rats 1 to 2 days after transfection. In control and transfected STZ diabetic rats, IGF-1 expression were examined by reverse transcription polymerase chain reaction （RT-PCR）, Western blot and histology. The penis β-galactosidase activity and localization of the STZ diabetic rats were also determined. Results： One to two days after transfection, the β-galactosidase was found in the smooth muscle cells of the diabetic rat penis transfected with AdCMV-βgal. One to 2 days after administration of AdCMV- IGF-1, the cavernosal pressure, as determined by the ratio of maximal intracavernous pressure-to-mean arterial pressure （ICP/MAP） and total intracavernous pressure （ICP）, was increased in response to cavernous nerve stimulation. Transgene expression was confirmed by RT-PCR, Western blot and histology. Conclusion： Gene transfer of IGF-1 significantly increased erectile function in the STZ diabetic rats. These results suggest that in vivo gene transfer of IGF- 1 might be a new therapeutic intervention for the treatment of erectile dysfunction （ED） in the STZ diabetic rats.

Insulin like growth factor-1 increases fatty liver preservation in IGL-1 solution

AIM: To investigate the benefits of insulin like growth factor-1 (IGF-1) supplementation to serum-free institut georges lopez-1 (IGL-1) solution to protect fatty liver against cold ischemia reperfusion injury. METHODS: Steatotic livers were preserved for 24 h in IGL-1  solution supplemented with or without IGF-1 and then perfused "ex vivo " for 2 h at 37℃. We examined the effects of IGF-1 on hepatic damage and function (transaminases, percentage of sulfobromophthalein clearance in bile and vascular resistance). We also studied other factors associated with the poor tolerance of fatty livers to cold ischemia reperfusion injury such as mitochondrial damage, oxidative stress, nitric oxide, tumor necrosis factor-α (TNF-α) and mitogen-activated protein kinases.RESULTS: Steatotic livers preserved in IGL-1 solutionsupplemented with IGF-1 showed lower transaminase levels, increased bile clearance and a reduction in vascular resistance when compared to those preserved in IGL-1solution alone. These benefits are mediated by activation of AKT and constitutive endothelial nitric oxide synthase (eNOS), as well as the inhibition of inflammatory cytokines such as TNF-α. Mitochondrial damage and oxidative stress were also prevented.CONCLUSION: IGL-1  enrichment with IGF-1 increasedfatty liver graft preservation through AKT and eNOS activation, and prevented TNF-α release during normothermic reperfusion.

Effects of Bifidobacterium infantis on cytokine-induced neutrophil chemoattractant and insulin-like growth factor-1 in the ileum of rats with endotoxin injury

BACKGROUND The digestive tract is the maximal immunizing tissue in the body, and mucosal integrity and functional status of the gut is very important to maintain a healthy organism. Severe infection is one of the most common causes of gastrointestinal dysfunction, and the pathogenesis is closely related to endotoxemia and intestinal barrier injury. Bifidobacterium is one of the main probiotics in the human body that is involved in digestion, absorption, metabolism, nutrition, and immunity.Bifidobacterium plays an important role in maintaining the intestinal mucosal barrier integrity. This study investigated the protective mechanism of Bifidobacterium during ileal injury in rats.AIM To investigate the effects of Bifidobacterium on cytokine-induced neutrophil chemoattractant(CINC) and insulin-like growth factor 1(IGF-1) in the ileum of rats with endotoxin injury.METHODS Preweaning rats were randomly divided into three groups: Control(group C),model(group E) and treatment(group T). Group E was intraperitoneally injected with lipopolysaccharide(LPS) to create an animal model of intestinal injury.Group T was intragastrically administered Bifidobacterium suspension 7 d before LPS. Group C was intraperitoneally injected with normal saline. The rats were killed at 2, 6 or 12 h after LPS or physiological saline injection to collect ilealtissue samples. The expression of ileal CINC mRNA was evaluated by reverse transcription-polymerase chain reaction(RT-PCR), and expression of ileal IGF-1 protein and mRNA was detected by immunohistochemistry and RT-PCR,respectively.RESULTS The ileum of rats in Group C did not express CINC mRNA, ileums from Group E expressed high levels, which was then significantly decreased in Group T(F =23.947, P < 0.05). There was no significant difference in CINC mRNA expression at different times(F = 0.665, P > 0.05). There was a high level of IGF-1 brown granules in ileal crypts and epithelial cells in Group C, sparse staining in Group E, and dark, dense brown staining in Group T. There was a significant difference between Groups C and E and Groups E and T(P < 0.05). There was no significant difference in IGF-1 protein expression at different times(F = 1.269, P > 0.05). IGF-1 mRNA expression was significantly different among the three groups(P < 0.05),though not at different times(F = 0.086, P > 0.05).CONCLUSION Expression of CINC mRNA increased in the ileum of preweaning rats with endotoxin injury, and exogenous administration of Bifidobacterium reduced CINC m RNA expression. IGF-1 protein and mRNA expression decreased in the ileum of preweaning rats with endotoxin injury, and exogenous administration of Bifidobacterium prevented the decrease in IGF-1 expression. Bifidobacterium may increase IGF-1 expression and enhance intestinal immune barrier function in rats with endotoxin injury.

MELD score,insulin-like growth factor 1 and cytokines on bone density in end-stage liver disease

AIM:To determine the contributions of insulin-like growth factor 1 (IGF-1),cytokines and liver disease severity to bone mineral density in patients pre-transplantation.METHODS:Serum IGF-1,tumor necrosis factor-α (TNFα) and interleukin 6 (IL-6) were measured and the Model for End-Stage Liver Disease (MELD) score calculated in 121 adult patients referred to a single centre for liver transplantation.Bone mineral density (BMD) of the lumbar spine and femoral neck were assessed via dual energy X-ray absorptiometry.Demographics,liver disease etiology,medication use and relevant biochemistry were recorded.RESULTS:A total of 117 subjects were included,with low BMD seen in 68.6%,irrespective of disease etiol-ogy.In multivariable analysis,low body mass index (BMI),increased bone turnover and low IGF-1 were independent predictors of low spinal bone density.At the hip,BMI,IGF-1 and vitamin D status were predictive.Despite prevalent elevations of TNFα and IL-6,levels did not correlate with degree of bone loss.The MELD score failed to predict low BMD in this pre-transplant population.CONCLUSION:Osteopenia/osteoporosis is common in advanced liver disease.Low serum IGF-1 is weakly predictive but serum cytokine and MELD score fail to predict the severity of bone disease.

Insulin-like growth factor receptor-1 overexpression is associated with poor response of rectal cancers to radiotherapy

AIM:To explore the potential correlation between insulin-like growth factor receptor-1(IGF-1R)expression and rectal cancer radiosensitivity.METHODS:Eighty-seven rectal cancer patients(c TNMⅠ-Ⅲ)treated in our department between January 2011and December 2012 were enrolled.All subjects were treated with preoperative radiotherapy and radical resection of rectal carcinoma.Immunohistochemistry and reverse transcription polymerase chain reaction(RT-PCR)were performed to detect IGF-1R expression in pre-treatment and postoperative colorectal cancer specimens.Radiosensitivity for rectal cancer specimens was evaluated by observing rectal carcinoma mass regression combined with fibrosis on HE staining,degree of necrosis and quantity of remaining tumor cells.The relative IGF-1R expression was evaluated for association with tumor radiosensitivity.RESULTS:Immunohistochemistry showed diffuse IGF-1R staining on rectal cancer cells with various degrees of signal density.IGF-1R expression was significantly correlated with c TNM staging(P=0.012)while no significant association was observed with age,sex,tumor size and degree of differentiation(P=0.424,0.969,0.604,0.642).According to the Rectal Cancer Regression Grades(RCRG),there were 31 cases of RCRG1(radiation sensitive),28 cases of RCRG2 and 28 cases of RCRG3(radiation resistance)in 87 rectal cancer subjects.IGF-1R protein hyper-expression was significantly correlated with a poor response to radiotherapy(P<0.001,r=0.401).RT-PCR results from pre-radiation biopsy specimens also showed that IGF-1R m RNA negative group exhibited a higher radiation sensitivity(P<0.001,r=0.497).Compared with the pre-radiation biopsy specimens,the paired post-operative specimens showed a significantly increased IGF-1R protein and m RNA expression in the residual cancer cells(P<0.001,respectively).CONCLUSION:IGF-1R expression level may serve as a predictive biomarker for radiosensitivity of rectal cancer before preoperative radiotherapy.

Human insulin-like growth factor 1-transfected umbilical cord blood neural stem cell transplantation improves hypoxic-ischemic brain injury

Human insulin-like growth factor 1-transfected umbilical cord blood neural stem cells were transplanted into a hypoxic-ischemic neonatal rat model via the tail vein. BrdU-positive cells at day 7 post-transplantation, as well as nestin- and neuron specific enolase-positive cells at day 14 were increased compared with those of the single neural stem cell transplantation group. In addition, the proportion of neuronal differentiation was enhanced. The genetically modified cell-transplanted rats exhibited enhanced performance in correctly crossing a Y-maze and climbing an angled slope compared with those of the single neural stem cell transplantation group. These results showed that human insulin-like growth factor 1-transfected neural stem cell transplantation promotes the recovery of the leaming, memory and motor functions in hypoxic-ischemic rats.

Role of insulin/insulin-like growth factor 1 signaling pathway in longevity

The insulin/insulin-like growth factor 1 (IGF-1) signaling pathway is evolutionary conserved in diverse speciesincluding C.elegans, saccharomyces cerevisiae, Drosophila melanogaster, rodents and humans, which is involved in many interrelated functions that are necessary for metabolism, growth and reproduction. Interestingly, more and more research has revealed that insulin/IGF-1 signaling pathway plays a pivotal role in the regulation of longevity. Generally, disruption of the power of this pathway will extend longevity in species ranging from C.elegansto humans. The role of insulin/IGF-1 in longevit yis probably related to stress resistance. Although the underlying mechanisms of longevity are not fully understood, the Insulin/IGF-1 signaling pathway has attracted substantial attention and it will be a novel target to prevent or postpone age-related diseases and extend life span. In this review, we mainly focus on the similar constitution and role of insulin/IGF-1 signaling pathway in C.elegans, saccharomyces cerevisiae, rodents and humans.

Effect of sericin on diabetic hippocampal growth hormone/insulin-like growth factor 1 axis

Previous studies have shown that sericin extracted from silk cocoon significantly reduces blood glucose levels and protects the nervous system against diabetes mellitus. In this study, a rat type 2 diabetes mellitus model was established by intraperitoneal injection of 25 mg/kg streptozotocin for 3 successive days, following which the rats were treated with sericin for 35 days. After treatment, the blood glucose levels of the diabetic rats decreased significantly, the growth hormone level in serum and its expression in the hippocampus decreased significantly, while the insulin-like growth factor-1 level in serum and insulin-like growth factor-1 and growth hormone receptor expression in the hippocampus increased significantly. The experimental findings indicate that sericin improves disorders of the growth hormone/insulin-like growth factor 1 axis to alleviate hippocampal damage in diabetic rats.

Effects of Insulin-like Growth Factor 1 Receptor and Its Inhibitor AG1024 on the Progress of Lung Cancer

Summary： The type 1 insulin-like growth factor receptor （IGF-1R） and its downstream signaling com- ponents have been increasingly recognized to drive the development of malignancies, including non-small cell lung cancer （NSCLC）. This study aimed to investigate the effects of IGF-1R and its in- hibitor, AG1024, on the progression of lung cancer. Tissue microarray and immunohistochemistry were employed to detect the expressions of IGF-1 and IGF-1R in NSCLC tissues （n=198）. Western blotting was used to determine the expressions oflGF-1 and phosphorylated IGF-1R （p-IGF-1R） in A549 human lung carcinoma cells, and MTT assay to measure cell proliferation. Additionally, the expressions of IGF-1, p-IGF-1R and IGF-1R in a mouse model of lung cancer were detected by Western blotting and real-time fluorescence quantitative polymerase chain reaction （FQ-PCR）, respectively. The results showed that IGF-1 and IGF-1R were overexpressed in NSCLC tissues. The expression levels of IGF-1 and p-IGF-1R were significantly increased in A549 cells treated with IGF-1 as compared to those treated with IGF-1 ＋AG 1024 or untreated cells. In the presence of IGF-1, the proliferation of A549 cells was significantly increased. The progression of lung cancer in mice treated with IGF-1 was significantly increased as compared to the group treated with IGF-l＋AG1024 or the control group, with the same trend mirrored in IGF-1/p-IGF-1R/IGF-1R at the protein and/or mRNA levels. It was concluded that IGF- 1 and IGF inhibitor AG 1024 promotes lung cancer progression.

A predictive score for retinopathy of prematurity by using clinical risk factors and serum insulin-like growth factor-1 levels

AIM：To detect the impact of insulin-like growth factor-1（IGF-1）and other risk factors for the early prediction of retinopathy of prematurity（ROP）and to establish a scoring system for ROP prediction by using clinical criteria and serum IGF-1 levels.METHODS：The study was conducted with 127 preterm infants.IGF-1 levels in the 1st day of life,1st,2nd,3rd and4th week of life was analyzed.The score was established after logistic regression analysis,considering the impact of each variable on the occurrences of any stage ROP.A validation cohort containing 107 preterm infants was included in the study and the predictive ability of ROP score was calculated.RESULTS：Birth weights（BW）,gestational weeks（GW）and the prevalence of breast milk consumption were lower,respiratory distress syndrome（RDS）,bronchopulmonarydysplasia（BPD）and necrotizing enterocolitis（NEC）were more frequent,the duration of mechanical ventilation and oxygen supplementation was longer in patients with ROP（P〈0.05）.Initial serum IGF-1 levels tended to be lower in newborns who developed ROP.Logistic regression analysis revealed that low BW（〈1250 g）,presence of intraventricular hemorrhage（IVH）and formula feeding increased the risk of ROP.Afterwards,the scoring system was validated on 107 infants.The negative predictive values of a score less than 4 were 84.3%,74.7%and 79.8%while positive predictive values were 76.3%,65.5%and71.6%respectively.CONCLUSION：In addition to BW〈1250 g and IVH,formula consumption was detected as a risk factor for the development of ROP.Breastfeeding is important for prevention of ROP in preterm infants.

Insulin-like growth factor 2 mRNA-binding protein 1 promotes cell proliferation via activation of AKT and is directly targeted by microRNA-494 in pancreatic cancer

BACKGROUND Studies have shown that insulin-like growth factor 2 mRNA-binding protein 1(IGF2BP1)plays critical roles in the genesis and development of human cancers.AIM To investigate the clinical significance and role of IGF2BP1 in pancreatic cancer.METHODS Expression levels of IGF2BP1 and microRNA-494(miR-494)were mined based on Gene Expression Omnibus datasets and validated in both clinical samples and cell lines by quantitative real-time polymerase chain reaction and Western blot.The relationship between IGF2BP1 expression and clinicopathological factors of pancreatic cancer patients was analyzed.The effect and mechanism of IGF2BP1 on pancreatic cancer cell proliferation were investigated in vitro and in vivo.Analyses were performed to explore underlying mechanisms of IGF2BP1 upregulation in pancreatic cancer and assays were carried out to verify the posttranscriptional regulation of IGF2BP1 by miR-494.RESULTS We found that IGF2BP1 was upregulated and associated with a poor prognosis in pancreatic cancer patients.We showed that downregulation of IGF2BP1 inhibited pancreatic cancer cell growth in vitro and in vivo via the AKT signaling pathway.Mechanistically,we showed that the frequent upregulation of IGF2BP1 was attributed to the downregulation of miR-494 expression in pancreatic cancer.Furthermore,we discovered that reexpression of miR-494 could partially abrogate the oncogenic role of IGF2BP1.CONCLUSION Our results revealed that upregulated IGF2BP1 promotes the proliferation of pancreatic cancer cells via the AKT signaling pathway and confirmed that the activation of IGF2BP1 is partly due to the silencing of miR-494.

Insulin-like growth factor binding protein related protein 1 knockdown attenuates hepatic ?brosis via the regulation of MMPs/TIMPs in mice

Background: Previous research suggested that insulin-like growth factor binding protein related protein 1(IGFBPrP1), as a novel mediator, contributes to hepatic fibrogenesis. Matrix metalloproteinases(MMP) and tissue inhibitors of metalloproteinases(TIMP) play an essential role in hepatic fibrogenesis by regulating homeostasis and remodeling of the extracellular matrix(ECM). However, the interaction between IGFBPrP1 and MMP/TIMP is not clear. The present study was to knockdown IGFBPrP1 to investigate the correlation between IGFBPrP1 and MMP/TIMP in hepatic fibrosis. Methods: Hepatic fibrosis was induced by thioacetamide(TAA) in mice. Knockdown of IGFBPrP1 expression by ultrasound-targeted microbubble destruction-mediated CMB-shRNA-IGFBPrP1 delivery, or inhibition of the Hedgehog(Hh) pathway by cyclopamine treatment, was performed in TAA-induced liver fibrosis mice. Hepatic fibrosis was determined by hematoxylin and eosin and Sirius red staining. Hepatic expression of IGFBPrP1, α-smooth muscle actin( α-SMA), transforming growth factor β 1(TGF β1), collagen I, MMPs/TIMPs, Sonic Hedgehog(Shh), and glioblastoma family transcription factors(Gli1) were investigated by immunohistochemical staining and Western blotting analysis. Results: We found that hepatic expression of IGFBPrP1, TGF β1, α-SMA, and collagen I were increased longitudinally in mice with TAA-induced hepatic fibrosis, concomitant with MMP2/TIMP2 and MMP9/TIMP1 imbalance and Hh pathway activation. Knockdown of IGFBPrP1 expression, or inhibition of the Hh pathway, reduced the hepatic expression of IGFBPrP1, TGF β1, α-SMA, and collagen I and re-established MMP2/TIMP2 and MMP9/TIMP1 balance. Conclusions: Our findings suggest that IGFBPrP1 knockdown attenuates liver fibrosis by re-establishing MMP2/TIMP2 and MMP9/TIMP1 balance, concomitant with the inhibition of hepatic stellate cell activation, down-regulation of TGF β1 expression, and degradation of the ECM. Furthermore, the Hh pathway mediates IGFBPrP1 knockdown-induced attenuation of hepatic fibrosis through the regulation of MMPs/TIMPs balance.

Interaction between insulin-like growth factor binding protein-related protein 1 and transforming growth factor beta 1 in primary hepatic stellate cells

BACKGROUND: We previously showed that insulin-like growth factor binding protein-related protein 1 (IGFBPrP1) is a novel mediator in liver fibrosis. Transforming growth factor beta 1 (TGF beta 1) is known as the strongest effector of liver fibrosis. Therefore, we aimed to investigate the detailed interaction between IGFBPrP1 and TGF beta 1 in primary hepatic stellate cells (HSCs). METHODS: We overexpressed TGF beta 1 or IGFBPrP1 and inhibited TGF beta 1 expression in primary HSCs for 6, 12, 24, 48, 72, and 96 hours to investigate their interaction and observe the accompanying expressions of a-smooth muscle actin (alpha-SMA), collagen I, fibronectin, and phosphorylated-mothers against decapentaplegic homolog 2/3 (p-Smad2/3). RESULTS: We found that the adenovirus vector encoding the TGF beta 1 gene (AdTGF beta 1) induced IGFBPrP1 expression while that of alpha-SMA, collagen I, fibronectin, and TGF beta 1 increased gradually. Concomitantly, AdIGFBPrP1 upregulated TGF beta 1, alpha-SMA, collagen I, fibronectin, and p-Smad2/3 in a time-dependent manner while IGFBPrP1 expression was decreased at 96 hours. Inhibition of TGF beta 1 expression reduced the IGFBPrP1-stimulated expression of alpha-SMA, collagen I, fibronectin, and p-Smad2/3. CONCLUSIONS: These findings for the first time suggest the existence of a possible mutually regulation between IGFBPrP1 and TGF beta 1, which likely accelerates liver fibrosis progression. Furthermore, IGFBPrP1 likely participates in liver fibrosis in a TGF beta 1-depedent manner, and may act as an upstream regulatory factor of TGF beta 1 in the Smad pathway.

RNA interference affects tumorigenicity and expression of insulin-like growth factor-1,insulin-like growth factor-1 receptor,and basic fibroblast growth factor-2 in rat C6 glioma cells

BACKGROUND： Human gliomas are more likely to express basic fibroblast growth factor-2 （FGF-2） insulin-like growth factor-1（IGF-1）, and IGF-1 receptor （IGF-1R） than normal brain tissue. These factors activate signal transduction systems of Ras/MAPK and PI3K/Akl, which promote glioma growth. OBJECTIVE： To utilize RNA interference （RNAi） technique to down-regulate FGF-2, IGF-1, and IGF-1R gene expression, and to investigate the effects of these genes on rat C6 glioma cells, as well as the feasibility of RNAi for treating glioma. DESIGN, TIME AND SETTING： This neurooncological, randomized, controlled, in vivo and in vitro experiment, which used RNAi methodology, was performed at the Laboratory of Molecular Biology, Institute of Biochemistry, Chinese Academy of Sciences between August 2005 and February 2008. MATERIALS： Rat C6 cell lines were purchased from Shanghai Institute of Cellular Biology Affiliated to Chinese Academy of Sciences. Small interfering RNA （siRNA） was synthesized by Shanghai GenePharma. Anti-IGF-1, anti-IGF-1R, anti-FGF-2, anti-mouse and anti-rabbit IgG G1-HRP antibodies were provided by Santa Cruz Biotechnology, USA. Four to six week-old BALB/c nude mice were purchased from the Laboratory Animal Center, Chinese Academy of Sciences. METHODS： C6 glioma cells were transfected with siRNA, which was chemically synthesized in vitro to correspond to endogenous FGF-2, IGF-1, and IGF-1R genes. The inhibition ratio of targeting mRNA expression was detected by semiquantitative RT-PCR, and protein expression was determined by Western blot analysis. C6 glioma cell proliferation was observed using a growth curve C6 glioma cell apoptosis rate and cell cycle were detected by flow cytometry. C6 glioma cell growth regression was observed by transwell migration assay. In addition, nude mouse subcutaneous tumor models were used in this study. For studying the anti-tumor effects of IGF-1 and IGF-1R siRNA, two blank control groups, with six mice each, were set up： A （2.5 μg siRNA was injected one week after C6 cells were inoculated, Le., when tumor volume reached 8 mm × 8 mm） and B （siRNA was injected at the same time with C6 cells were inoculated. To study the effects of FGF-2 siRNA, the groups consisted of a blank control group, negative control group, 2.6 μg siRNA group, 4 μg siRNA group, and 5.3 μg siRNA group, with six mice each. MAIN OUTCOME MEASURES： mRNA and protein inhibition ratio of FGF-2, IGF-1, and IGF-1 R; C6 glioma cell proliferation, apoptosis, and cycle growth arrest; C6 glioma cell growth regression and subcutaneous tumorigenicity rates. RESULTS： All siRNA constructs proved to be effective. After 48 hours, transfection of 200 nmol/L siRNA resulted in a FGF-2 or IGF-1R gene inhibition ratio 〉 80% and an IGF-1 gene inhibition ratio of approximately 70%. Protein expression levels for FGF-2, IGF-1, and IGF-1R decreased in a dose-dependent manner following siRNA transfection, with an inhibition rate 〉 85%, 60%, and 50%, respectively. C6 glioma cell proliferation and apoptosis rates increased in proportion to siRNA. The apoptosis rate of C6 glioma cells induced by FGF-2, IGF-1, and IGF-1R siRNA was 39.96%, 15.07% and 22.47%, respectively （P 〈 0.01）. Transfection of 200 nmol/L IGF or IGF-1R siRNA for 48 hours suppressed C6 glioma cell migration. At 30 days after intratumoral injection of 2.6, 4, and 5.3 tJg FGF-2 siRNA, tumor growth regression rate of FGF-2 siRNA was 56%, 67%, and 86%, respectively. The tumor growth regression rate was 71.88% and 45.71%, respectively, when IGF-1 or IGF-1R siRNA was intratumorally injected 1 week after C6 glioma cell transplantation. When IGF-1 or IGF-1 R siRNA was intratumorally injected during C6 glioma cell transplantation, the tumor growth regression rate was 78.13% and 74.29%, respectively. CONCLUSION： siRNA transfection downregulated gene expression of FGF-2, IGF-1, and IGF-1R In addition, siRNA treatment markedly suppressed glioma cell proliferation, growth, and migration, and concomitantly reduced subcutaneous tumorigenicity.

Electroacupuncture-attenuated ischemic brain injury increases insulin-like growth factor-1 expression in a rat model of focal cerebral ischemia

Acupuncture has recently gained popularity in many countries as an alternative and complementary therapeutic intervention. Previous studies have shown that changes in genes, proteins, and their metabolites were measureable during acupuncture for treatment of cerebral ischemia. Through the use of in situ hybridization and immunohistochemistry, the present study confirmed that electroacupuncture increased insulin-like growth factor-1 mRNA and protein expression in the corpus stfiatum following cerebral ischemia, reduced brain edema following middle cerebral artery occlusion reperfusion, and decreased infarct volume. Results suggested that electroacupuncture is effective in the relief of cerebral ischemia by increasing endogenous insulin-like growth factor-1 expression.

Paravertebral fascial massage promotes brain development of neonatal rats via the insulin-like growth factor 1 pathway

Massage in traditional Chinese medicine can promote body and brain development of premature and normal newborn infants. In the present study, neonatal rats （1 day old） underwent paravertebral fascial massage （15 consecutive days）, followed by subcutaneous injection of insulin-like growth factor 1 receptor antagonist, JB1 （9 consecutive days）. Paravertebral fascial massage significantly increased insulin-like growth factor 1 expression and cell proliferation in the subventricular zone of the lateral ventricle and dentate gyrus of the hippocampus. However, JB1 inhibited this increase. Results suggest that paravertebral fascial massage can promote brain development of neonatal rats via the insulin-like growth factor I pathway.

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.

Associations between Placental Insulin-Like Growth Factor-1 Gene Expression, DNA Methylation and Intrauterine Growth Restriction

Intrauterine growth restriction (IUGR) is a common fetal development disorder which has great impact on neonatal health. Insulin-like growth factor-1 (IGF1) has an important role in regulating fetal growth. Whether IGF1 DNA methylation was associated with IUGR has not been studied. Placenta samples from IUGR (n = 27) and normal delivery (n = 29) were collected whereas basic information of mothers and infants were also collected. RT-PCR was performed to examine IGF1 transcriptions and bisulfite sequencing PCR was used for DNA methylation analysis. Gene expression analysis found IUGR had significantly lower IGF1 transcription compared to control group (IUGR: 0.330 ± 0.351;control group: 1.001 ± 0.800, t = 3.995, P IGF1 were all highly methylated and there is no difference on DNA methylation rate between IUGR and control group (IUGR: 75%;control group: 81%;P = 0.09). Interestingly, in both IUGR and control groups, male fetus had significantly higher methylation rate than female fetus (IUGR: male: 87%;female: 74%, P = 0.016;control: male: 82%;female: 69%, P = 0.012). There was no correlation between IGF1gene expression and DNA methylation rate (r = 0.095, P = 0.063). Intrauterine fetal growth restriction placenta had significantly lower IGF1gene expression;however, IGF1 DNA methylation level was similar. A potential fetus gender difference was also found in IGF1 DNA methylation rate.

Preparatory training attenuates drastic response of the insulin-like growth factor binding protein 1 at the point of maximal oxygen consumption in handball players

Background:Intensive exercise changes physiological need for glucose and several biochemical pathways responsible for its metabolism response.Among them are those which involve insulin,insulin-like growth factor(IGF-1),and IGF-binding proteins(IGFBPs).Different types and degrees of exercise,as well as an athlete's fitness,may induce a range of responses regarding concentrations and time needed for the alteration.The idea of the work was to find out whether and how insulin/IGF axis responds to additional physical activity in the already trained subjects and if so,is the adaptation potentially beneficial from the aspect of metabolic control.Methods:The effect of 4-week intensive training on campus(preparatory training) on the levels of insulin,IGF-1,and IGFBPs during maximal progressive exercise test(MPET) on a treadmill was compared to the results obtained during MPET conducted after a regular training season of a female elite handball team(n = 17,age:17 ± 1 years,height:171 ± 8 cm,weight:65 ± 8 kg,body mass index:22 ± 1 kg/m^2 at the beginning of the study;there were no significant changes at the end).Serum samples were obtained from players immediately before the test(basal),at the end of the test after reaching the point of maximal oxygen consumption(VO_(2max)),and after recovery.Results:The concentration of insulin decreased at VO_(2max),but remained higher in players after preparatory training(12.2 ± 2.5 m U/L vs.8.9 ± 4.4 m U/L,p = 0.049).The level of IGFBP-1 decreased in players at VO_(2max) in either case of training,but it remained much higher in tests performed after the preparatory regime than before(p = 0.029).Concentrations of IGF-1,IGFBP-2,-3,and-4 did not change significantly.Conclusion:The inverse relation between insulin and IGFBP-1 was lost during MPET,as these 2 molecules changed in the same direction.The results obtained suggest less severe stress-induced depression of insulin and IGFBP-1 after preparatory training.But another metabolic mechanism cannot be excluded,and that is potentially impaired insulin sensitivity resulting in higher level of IGFBP-1.