The IGF-PAPP-A-Stanniocalcin Axis in Serum and Ascites Associates with Prognosis in Patients with Ovarian Cancer

Pregnancy-associated plasma protein-A (PAPP-A) and PAPP-A2 modulate insulin-like growth factor (IGF) action and are inhibited by the stanniocalcins (STC1 and STC2). We previously demonstrated increased PAPP-A and IGF activity in ascites from women with ovarian carcinomas. In this prospective, longitudinal study of 107 women with ovarian cancer and ascites accumulation, we determined corresponding serum and ascites levels of IGF-1, IGF-2, PAPP-A, PAPP-A2, STC1, and STC2 and assessed their relationship with mortality. As compared to serum, we found highly increased ascites levels of PAPP-A (51-fold) and PAPP-A2 (4-fold). Elevated levels were also observed for IGF-1 (12%), STC1 (90%) and STC2 (68%). In contrast, IGF-2 was reduced by 29% in ascites. Patients were followed for a median of 38.4 months (range: 45 days to 8.9 years), during which 73 patients (68.2%) died. Overall survival was longer for patients with high serum IGF-1 (hazard ratio (HR) per doubling in protein concentration: 0.60, 95% CI: 0.40-0.90). However, patients with high ascites levels of IGF-1 showed a poorer prognosis (HR: 2.00 (1.26-3.27)). High serum and ascites IGF-2 levels were associated with increased risk of mortality (HR: 2.01 (1.22-3.30) and HR: 1.78 (1.24-2.54), respectively). Similarly, serum PAPP-A2 was associated with mortality (HR: 1.26 (1.08-1.48)). Our findings demonstrate the presence and activity of the IGF system in the local tumor ecosystem, which is likely a characteristic feature of malignant disease and plays a role in its peritoneal dissemination. The potential clinical implications are supported by our finding that serum levels of the proteins are associated with patient prognosis.

Associations of insulin-like growth factor binding protein-2 (IGFBP-2) with metabolic profile and hepatic fat deposition in asymptomatic men and women

BACKGROUND AND HYPOTHESIS

Low circulating levels of insulin-like growth-factor binding protein-2 (IGFBP-2) have been associated with increased adiposity and metabolic alterations such as insulin resistance, dyslipidemia, and non-alcoholic fatty liver disease in individuals with obesity. However, whether IGFBP-2 affects energy metabolism in the early stages of these disorders remains unclear. Herein, we hypothesized that plasma IGFBP-2 concentrations are inversely associated with early liver fat accumulation and alterations in lipid and glucose homeostasis in apparently healthy and asymptomatic men and women.

METHODS

333 middle-aged Caucasian men and women apparently healthy and without cardiovascular symptoms were enrolled for a cross-sectional cardiometabolic imaging study. Individuals with BMI ≥ 40 kg/m², cardiovascular disease, dyslipidemia, hypertension, and diabetes were excluded. Fasting glucose and lipid profiles were measured and an oral glucose tolerance test was performed. Liver fat content was assessed by magnetic resonance spectroscopy. Volume of visceral adipose tissue (VAT) was evaluated by magnetic resonance imaging. Plasma IGFBP-2 levels were quantified by ELISA.

RESULTS

Participants with low IGFBP-2 levels were characterized by a higher body fat mass (p<0.0001), insulin resistance (p<0.0001), higher plasma triglyceride (TG) (p<0.0001) and lower HDL-cholesterol levels (p<0.0001) in a sex-independent manner. IGFBP-2 levels were inversely correlated with liver fat fraction in both men (r=-0.36, p<0.0001) and women (r=-0.40, p<0.0001). IGFBP-2 concentrations were negatively associated with hepatic fat fraction independently of age and VAT in both men (R²=0.23, p=0.012) and women (R²=0.27, p=0.028).

CONCLUSIONS

Our findings show that even in asymptomatic, apparently healthy individuals, low IGFBP-2 levels are associated with a more deteriorated cardiometabolic risk profile and with a high hepatic fat content in a VAT-independent manner. However, IGFBP-2 does not appear to influence the established sexual dysmorphism observed for metabolic variables and hepatic fat fraction. Additional studies are required to better understand the relationships between IGFBP-2 and liver fat content.

Screening and characterization of a novel efficient tumor cell-targeting peptide derived from insulin-like growth factor binding proteins

Targeted delivery of antitumor drugs is particularly important in tumor treatment. Tumor-targeted peptide is a very effective drug carrier for tumor therapy. Here, we screened and characterized a highly efficient targeted peptide named IHP5, which was derived from insulin-like growth factor binding proteins (IGFBPs). IHP5 exhibited preferential binding to the tested tumor cell lines. The delivery efficiency of IHP5 was higher in various tested tumor cells than in normal cells, especially in the human cervical cancer cell line HeLa, which was 11.7-fold higher than in normal human embryonic kidney cells HEK293. Moreover, the penetration efficiency of IHP5 was 13 times higher than that of the classical cell penetrating peptide TAT in HeLa cells. Detail analysis revealed that IHP5 endocytosis was possibly correlated with acetylated heparan sulfate proteoglycans including phosphatidylinositol proteoglycan 3 (GPC3), phosphatidylinositol proteoglycan 5 (GPC5) and syndecan 2 (SDC2). Subsequently, the introduction of IHP5 enhanced the inhibitory effect of trichosanthin (TCS) on tumor cells, resulting in at least 19-fold increase in tumor cells without enhanced cytotoxicity in normal cells HEK293. These results suggested that IHP5, as a novel tumor cell-targeting penetrating peptide with the ability to target tumor cells, has great potential in drug delivery applications.

A Systematic Review and Meta-Analysis on the Effect of Flavonoids on Insulin-like Growth Factor and Insulin-like Growth Factor Binding Protein and Incidence of Breast Cancer

BACKGROUND

Insulin-like growth factor (IGF-1) is associated with breast cancer in menopausal women. Naturally occurring biomolecules found in common dietary protocols, such as flavonoids, play a key role in the inhibition and treatment of cancer. In-vitro/in-vivo studies showed that treatment involving flavonoids led to a reduced risk of breast cancer due to the decrease of IGF-1 level in addition to an increased insulin-like growth factor binding protein (IGFBP)-3. However, clinical studies did not show conclusive results in this regard because they are contradictory.

OBJECTIVE

The aim of the present study was to find the effect of flavonoids on IGF-1 and IGFBP-3 and the incidence of breast cancer.

METHODS

This systematic review was performed using PubMed, Scopus, ISI Web of Science, and EMBASE databases to collect results about the clinical use of flavonoids and their effects on breast cancer. After eliminating duplicate articles, the title and abstract of the remaining articles were examined in thematic communication, and related clinical articles were selected and studied based on inclusion criteria. The data were extracted from each article, and then statistical analysis was subsequently carried out by Comprehensive Meta-Analysis.

RESULTS

The results showed that the effect of flavonoids on changes in IGF1 and IGFBP-3 was not statistically significant. No significant heterogeneity was detected across the studies. Pooled effect size also indicated that the mean change was not statistically significant. No significant heterogeneity was detected across the studies. There was no evidence of publication bias for IGF1 and IGFBP-3.

CONCLUSION

This meta-analysis study suggests that flavonoid supplementations have no significant effect on IGF-1 and IGFBP-3, and a high soy diet has beneficial effects on IGF system components, which might be useful in breast cancer.

Longitudinal Analysis of Urinary Cytokines and Biomarkers in COVID-19 Patients with Subclinical Acute Kidney Injury

In hospitalized COVID-19 patients, disease progression leading to acute kidney injury (AKI) may be driven by immune dysregulation. We explored the role of urinary cytokines and their relationship with kidney stress biomarkers in COVID-19 patients before and after the development of AKI. Of 51 patients, 54.9% developed AKI. The principal component analysis indicated that in subclinical AKI, epidermal growth factor (EGF) and interferon (IFN)-α were associated with a lower risk of AKI, while interleukin-12 (IL-12) and macrophage inflammatory protein (MIP)-1β were associated with a higher risk of AKI. After the manifestation of AKI, EGF and IFN-α remained associated with a lower risk of AKI, while IL-1 receptor (IL-1R), granulocyte-colony stimulating factor (G-CSF), interferon-gamma-inducible protein 10 (IP-10) and IL-5 were associated with a higher risk of AKI. EGF had an inverse correlation with kidney stress biomarkers. Subclinical AKI was characterized by a significant up-regulation of kidney stress biomarkers and proinflammatory cytokines. The lack of EGF regenerative effects and IFN-α antiviral activity seemed crucial for renal disease progression. AKI involved a proinflammatory urinary cytokine storm.

Association of Salivary IGF and IGF/IGFBP-3 Molar Ratio with Cervical Vertebral Maturation Stages from Pre-Adolescent to Post-Adolescent Transition Period-A Cross-Sectional Exploratory Study

Background: The relevance of growth determination in orthodontics is driving the search for the most precise and least invasive way of tracking the pubertal growth spurt. Objectives: The aim was to explore whether minimally invasive salivary estimation of biomarkers Insulin-like growth factor (IGF-1) and Insulin-like growth factor binding protein-3 (IGFBP-3) could be used to estimate skeletal maturity with diagnostic accuracy, especially in children and adolescent age groups. Subjects and methods: The cross-sectional study was conducted on 105 participants aged 6−25 years from the out-patient Department of Preventive Dental Science at Majmaah University between the period 2 January 2021 and 12 July 2021. Each subject’s lateral cephalogram radiograph was categorized based on skeletal maturity, and saliva samples were estimated for IGF-1 and IGFBP-3 using the respective ELISA kits. Two-way ANOVA with interaction was applied to examine the main effects due to cervical vertebral maturation staging (CVS), Sex and interaction effect due to CVS, and Sex on study parameters. Karl Pearson’s Product Moment Correlation Coefficient was calculated for finding a significant association between IGF, IGFBP3, and the IGF-1/IGFBP3 molar ratio. Results: Highest mean salivary IGF-1 was observed in the pubertal peak stage, which coincides with cervical vertebral maturity stages 3 and 4 (CVS3 and CVS4) for both males (2.57 ng/mL) and females (1.57 ng/mL) and the lowest mean level of IGF-1 for females (0.85 ng/mL) and males (1.22 ng/mL) was observed during the prepubertal stage. There exists a significant variation in IGF-1 between males and females in the pubertal stage (p < 0.01), but the difference is very narrow in the prepubertal and post-pubertal groups (p > 0.05). There was no significant interaction effect of different skeletal stages and gender on the IGFBP3 and the IGF-1/IGFBP3 molar ratio (p > 0.05), but there exists a significant interaction effect on IGF-1 (p < 0.05). Conclusion: Estimation of the IGF-1 and the IGF-1/IGFBP3 molar ratio in saliva, being a non-invasive biological marker, could serve as an adjunctive tool along with radiographic assessment in estimating growth maturity in the adolescence age group. By initiating orthodontic treatment during the mandibular growth peak in adolescence, a positive outcome is ensured in managing skeletal deformities within the craniofacial complex.

Correlation between Salivary Levels of IGF-1, IGFBP-3, IGF-1/IGFBP3 Ratio with Skeletal Maturity Using Hand-Wrist Radiographs

Objective: The relevance of growth determination in orthodontics is driving the search for the most precise and least invasive way of tracking the pubertal growth spurt. Our aim was to explore whether minimally invasive salivary estimation of biomarkers Insulin-like growth factor (IGF-1) and Insulin-like growth factor binding protein-3 (IGFBP-3) could be used to estimate skeletal maturity for clinical convenience, especially in children and adolescent age groups. Materials and Method: The cross-sectional study was conducted on 90 participants (56 girls and 34 males) with ages ranging from 6 to 25 years. Each subject’s hand-wrist radiograph was categorized based on skeletal maturity, and saliva samples were estimated for IGF-1 and IGFBP-3 using the respective ELISA kits. Kruskal−Wallis nonparametric ANOVA was applied to compare different skeletal stages. Results: The study demonstrated low salivary IGF-1 levels at the prepubertal stage, with increase during pubertal onset and peak pubertal stage followed by a decline during pubertal deceleration to growth completion. Spearman’s correlation coefficient demonstrated a strong positive association (r = 0.98 p < 0.01) between salivary IGF/IGFBP-3 ratio and different stages of skeletal maturity. Conclusion: Salivary IGF-1, IGFBP-3, and IGF/IGFBP-3 ratio could serve as a potential biochemical marker for predicting the completion of skeletal maturity.

The Origination of Growth Hormone/Insulin-Like Growth Factor System: A Story From Ancient Basal Chordate Amphioxus

The growth hormone/insulin-like growth factor (GH/IGF) system, also called the pituitary-liver axis, has a somatotrophic role in the body. Although the GH/IGF system has always been regarded as a vertebrate-specific endocrine system, its actual origin remained unknown for a long time. The basal chordate, amphioxus, occupies an evolutionary position between vertebrates and invertebrates. Impressively, most of the members of the GH/IGF system are present in the amphioxus. The GH-like molecule in the amphioxus is mainly expressed in Hatschek's pit. It functions similarly to vertebrate GH and has a GH receptor-like binding partner. The amphioxus IGF-like peptide shows mitogenic activity and an expression pattern resembling that of vertebrate IGF-I. The receptor of IGF-like peptide and IGF binding protein (IGFBP) have also been demonstrated to exist in the amphioxus. These results reveal the origin of the gene families in the GH/IGF system, providing strong evidence that this system emerged in the amphioxus.

Cathepsin G-Induced Insulin-Like Growth Factor (IGF) Elevation in MCF-7 Medium Is Caused by Proteolysis of IGF Binding Protein (IGFBP)-2 but Not of IGF-1

Cathepsin G (CG), a neutrophil serine protease, induces cell migration and multicellular aggregation of human breast cancer MCF-7 cells. It has been suggested that tumor cell aggregates are associated with tumor embolism, thus CG-induced cell aggregation may promote tumor metastasis. We have revealed that cell aggregation is caused by elevated free insulin-like growth factor (IGF)-1 in the medium, followed by activation of IGF-1 receptor (IGF-1R). However, the molecular mechanism underlying IGF-1 elevation induced by CG remains unclear. Here, we aimed to elucidate the mechanism by examining the degradative effects of CG on IGF-1, and the IGF binding proteins (IGFBPs), which interfere with the binding of IGF-1 to its receptor. CG specifically evoked MCF-7 cell aggregation at less than 1 nM in a dose-dependent manner, however, neutrophil elastase (NE), chymotrypsin, and trypsin did not. Free IGF-1 concentration was continuously elevated in the medium of cells treated with CG, whereas treatments with other serine proteases resulted in only a transient or slight increase. IGFBP-2, the predominant IGFBP in MCF-7 cells, was gradually digested by CG. CG did not cleave IGF-1 for at least 48 h, whereas other proteases completely digested it. Moreover, CG induced continuous phosphorylation of IGF-1R and Akt, whereas NE-induced phosphorylation was transient, possibly due to insulin receptor substrate (IRS)-1 digestion. These results indicated that CG-specific IGF-1 elevation in the medium is caused by digestion of IGFBP-2, not IGF-1. Hence, this study clarifies the molecular mechanism of CG-specific cell aggregation.

Pregnancy-Associated Plasma Protein-A2 Is Associated With Mortality in Patients With Lung Cancer

Pregnancy-associated plasma protein-A (PAPP-A) and its homolog PAPP-A2 are enzymes that modulate the availability and mitogenic activity of insulin-like growth factor-I (IGF-I). PAPP-A has been implicated in numerous cancers but reports on PAPP-A2 in malignancy are non-existent. In a prospective observational study of 689 patients under suspicion of lung cancer, we examined levels of PAPP-A and PAPP-A2 and their relationship with mortality. Serum PAPP-A and PAPP-A2 concentrations were determined in pre-diagnostic blood samples using ELISA, and immunohistochemical staining of PAPP-A and PAPP-A2 was performed in malignant tissue from five operable patients. A total of 144 patients were diagnosed with lung cancer, whereas the diagnosis was rejected in 545 subjects, who served as a control group. PAPP-A2 concentrations were higher in patients with lung cancer [median (IQR): 0.33 (0.21-0.56) ng/mL] than in controls [0.27 (0.17-0.39) ng/mL], p < 0.001, whereas PAPP-A levels did not differ. Presence of PAPP-A and PAPP-A2 were confirmed in tumor specimens, and staining occurred in a heterogeneous pattern. Patients were observed for a median (range) of 7 (6; 8) years, during which 114 patients (79.2%) died. Patient mortality differed according to PAPP-A2 tertile (p < 0.001). PAPP-A2 was associated with mortality with an unadjusted hazard ratio (95% CI) per doubling in protein concentration of 1.30 (1.12; 1.53), p = 0.001. In a multivariable model adjusted for age, sex, and BMI, PAPP-A2 remained predictive of the endpoint with a hazard ratio per doubling in protein concentration of 1.25 (1.05; 1.48), p = 0.013. Collectively, PAPP-A2, but not PAPP-A, is elevated in patients with lung cancer and associated with mortality. This novel role of PAPP-A2 in cancer warrants further functional studies as well as validation in external cohorts.

Physiological Regulation of Growth during Social Ascension in a Group-Living Fish

In social groups, dominant animals typically are larger and have better access to resources than subordinates. When subordinates are given the opportunity to ascend to a dominant position, they will elevate their rates of growth to help secure dominance. This study investigated the physiological mechanisms facilitating this increased growth. Using the group-living cichlid, Neolamprologus pulcher, we investigated whether the insulin-like growth factor (IGF) system-a key regulator of growth-is involved in the regulation of growth during social ascension. We also assessed differences in energy storage and expenditure among dominant, subordinate, and ascending males to determine the energetic costs associated with ascension. Daily growth rates tripled during ascension, and ascending males expended more energy after ascension, owing to higher rates of energetically costly social behaviors, increased locomotor activity, and larger home ranges. Ascenders did not increase food intake to offset increasing energetic costs but had half the liver glycogen energy stores of subordinates. Together, these results indicate a reliance on stockpiled energy reserves to fuel the high energetic demands associated with ascension. Transcript abundance of IGF binding proteins 1 (igfbp1) and 2a (igfbp2a) were low in ascenders relative to subordinates, suggesting a higher capacity for growth during ascension through increased bioavailability of circulating IGF-1. Our findings provide clear evidence of the energetic costs of social ascension and offer novel insight into the physiological mechanisms modulating the social regulation of growth.

Insulin-Like Growth Factor Axis Biomarkers and Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

The insulin-like growth factor (IGF) axis has been implicated in glucose homeostasis. It is plausible to hypothesize that the IGF axis is involved in the development of gestational diabetes mellitus (GDM). In a systematic review of the evidence on IGF axis biomarkers in relation to GDM, we searched the PubMed and EMBASE for publications up to May 31, 2018, on the associations of circulating IGF axis biomarkers with GDM. Eligible studies must meet the pre-specified quality assessment criteria. Meta-analyses were conducted where there were at least three studies on the same biomarker at the same gestational age window-early (<20 weeks), mid (20-29 weeks), or late (30+ weeks) gestation. Twelve studies were included (484 GDM, 1755 euglycemic pregnancies). Meta-analyses showed that GDM was consistently associated with higher IGF-I concentrations in mid-gestation (six studies) and late gestation (six studies). There were only two studies on IGF-I in early gestation and GDM with inconsistent findings. GDM was associated with lower IGFBP-2 concentrations in early, mid-, or late gestation, according to data from one or two studies. GDM was associated with higher IGFBP-3 concentrations in late gestation according to a meta-analysis of five studies. There was no association with GDM for IGFBP-3 in early or mid-gestation, according to data from one study. Other IGF axis biomarkers (IGF-II, IGFBP-1,-4,-5-6, and -7) showed no or inconsistent associations, and the data at early gestation were scanty or absent. Available evidence is suggestive but inconclusive concerning whether the IGF axis is involved in the development of GDM. More studies on IGF axis biomarkers in early gestation are warranted. If a specific IGF axis molecule is proven to be involved in the development of GDM, this may point to a new molecular target for designing interventions to reduce the incidence of GDM.

Insulin-Like Growth Factor-Binding Proteins of Teleost Fishes

The insulin-like growth factor (Igf) binding protein (Igfbp) family has a broad range of physiological functions and a fascinating evolutionary history. This review focuses on the Igfbps of teleost fishes, where genome duplication events have diversified gene repertoire, function, and physiological regulation-with six core Igfbps expanded into a family of over twenty genes in some lineages. In addition to briefly summarizing the current state of knowledge on teleost Igfbp evolution, function, and expression-level regulation, we highlight gaps in our understanding and promising areas for future work.

Insulin-Like Growth Factor Binding Proteins and IGFBP Proteases: A Dynamic System Regulating the Ovarian Folliculogenesis

The aim of the present article is to update our understanding of the expression of the insulin-like growth factor binding proteins (IGFBPs), IGFBP proteases and their implication in the different processes of ovarian folliculogenesis in mammals. In the studied species, IGFs and several small-molecular weight IGFBPs (in particular IGFBP-2 and IGFBP-4) are considered, respectively, as stimulators and inhibitors of follicular growth and maturation. IGFs play a key role in sensitizing ovarian granulosa cells to FSH action during terminal follicular growth. Concentrations of IGFBP-2 and IGFBP-4 in follicular fluid strongly decrease during follicular growth, leading to an increase in IGF bioavailability. Inversely, atresia is characterized by an increase of IGFBP-2 and IGFBP-4 levels, leading to a decrease in IGF bioavailability. Changes in intrafollicular IGFBPs content are due to variations in mRNA expression and/or proteolytic degradation by the pregnancy-associated plasma protein-A (PAPP-A), and likely participates in the selection of dominant follicles. The identification of PAPP-A2, as an IGFBP-3 and -5 protease, and stanniocalcins (STCs) as inhibitors of PAPP-A activity extends the IGF system. Studies on their implication in folliculogenesis in mammals are still in the early stages.

Serum Insulin-Like Growth Factor Axis and the Risk of Pancreatic Cancer: Systematic Review and Meta-Analysis

Objective: To investigate the association between serum concentration of insulin-like growth factor (IGF) and the risk of pancreatic cancer (PaC). Methods: We identified eligible studies in Medline and EMBASE databases (no reference trials from 2014 to 2016) in addition to the reference lists of original studies and review articles on this topic. A summary of relative risks with 95% confidence intervals (CI) was calculated using a random-effects model. The heterogeneity between studies was assessed using Cochran Q and I² statistics. Results: Ten studies (seven nested case-control studies and three retrospective case-control studies) were selected as they met our inclusion criteria in this meta-analysis. All these studies were published between 1997 and 2013. The current data suggested that serum concentrations of IGF-I, IGF-II and insulin-like growth factor binding protein-3 (IGFBP-3)in addition to the IGF-I/IGFBP-3 ratio were not associated with an increased risk of PaC (Summary relative risks (SRRs) = 0.92, 95% CI: 0.67–1.16 for IGF-I; SRRs = 0.84, 95% CI: 0.54–1.15 for IGF-II; SRRs = 0.93, 95% CI: 0.69–1.17 for IGFBP-3; SRRs = 0.97, 95% CI: 0.71–1.23 for IGF-I/IGFBP-3 ratio). There was no publication bias in the present meta-analysis. Conclusion: Serum concentrations of IGF-I, IGF-II, IGFBP-1 and IGFBP-3 as well as the IGF-I/IGFBP-3 ratio were not associated with increased risk of PaC.

Early midtrimester serum insulin-like factors and cervical length to predict preterm delivery

OBJECTIVE

To investigate which ultrasound findings or serum biomarkers, including insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 1 and 3 (IGFBP-1 and IGFBP-3, respectively), in the first and early second trimesters are the best predictors for preterm delivery.

MATERIALS AND METHODS

This was a case-control study conducted between March 2011 and March 2013 with women presenting for routine antenatal care at 11-18 weeks. We collected serum samples from pregnant women and stored them at -80°C. All patients underwent cervical length (CL) measurement at 18-21 weeks. We retrieved frozen samples for analysis from women with subsequent preterm and term delivery. Prediction models were developed using multivariate stepwise logistic regression. Receiver-operating characteristics curves were used to determine the most useful cutoff point.

RESULTS

Of the 72 women recruited, 24 women underwent spontaneous preterm delivery, and 48 women with term delivery were randomly selected as the control group, in a 1:2 ratio. The maternal serum concentration of IGFBP-3 and CL were significantly associated with preterm birth.

CONCLUSION

Among the various known ultrasound findings and serum biomarkers in the early midtrimester, only CL and IGFBP-3 are independent predictors for preterm delivery in asymptomatic women.

Effect of insulin-like growth factor-I during the early postnatal period in intrauterine growth-restricted rats

BACKGROUND

Insulin-like growth factor-I (IGF-I) is essential for perinatal growth and development; low serum IGF-I has been observed during intrauterine growth restriction (IUGR). We investigated the effects of recombinant human (rh) IGF-I in IUGR rats during the early postnatal period.

METHODS

Intrauterine growth restriction was induced by bilateral uterine artery ligation in pregnant rats. IUGR pups were divided into two groups injected daily with rhIGF-I (2 mg/kg; IUGR/IGF-I, n = 16) or saline (IUGR/physiologic saline solution (PSS), n = 16) from postnatal day (PND) 7 to 13. Maternal sham-operated pups injected with saline were used as controls (control, n = 16). Serum IGF-I and IGF binding proteins (IGFBP) 3 and 5 were measured on PND25. The expression of Igf-i, IGF-I receptor (Igf-ir), Igfbp3, and 5 mRNA in the liver and brain was measured using real-time polymerase chain reaction on PND25. Immunohistochemical staining of the liver for IGF expression was performed.

RESULTS

Mean bodyweight on PND3 and PND25 in the IUGR pups (IUGR/IGF-I and IUGR/PSS) was significantly lower than that of the control pups. Serum IGF-I and hepatic Igf-ir mRNA in the IUGR pups were significantly lower than those in the control pups. In the IUGR/IGF-I group, hepatic Igfbp3 mRNA and liver immunohistochemical staining were increased. In the IUGR/PSS and control pups, there were no significant differences between these two groups in serum IGFBP3 and IGFBP5, hepatic Igf-i and Igfbp-5 mRNA, or brain Igf mRNA.

CONCLUSIONS

No benefits on body and brain weight gain but an effective increase in hepatic IGFBP-3 was observed after treatment with 2 mg/kg rhIGF-I during the early postnatal period.

A Meta-analysis of Individual Participant Data Reveals an Association between Circulating Levels of IGF-I and Prostate Cancer Risk

The role of insulin-like growth factors (IGF) in prostate cancer development is not fully understood. To investigate the association between circulating concentrations of IGFs (IGF-I, IGF-II, IGFBP-1, IGFBP-2, and IGFBP-3) and prostate cancer risk, we pooled individual participant data from 17 prospective and two cross-sectional studies, including up to 10,554 prostate cancer cases and 13,618 control participants. Conditional logistic regression was used to estimate the ORs for prostate cancer based on the study-specific fifth of each analyte. Overall, IGF-I, IGF-II, IGFBP-2, and IGFBP-3 concentrations were positively associated with prostate cancer risk (Ptrend all ≤ 0.005), and IGFBP-1 was inversely associated weakly with risk (Ptrend = 0.05). However, heterogeneity between the prospective and cross-sectional studies was evident (Pheterogeneity = 0.03), unless the analyses were restricted to prospective studies (with the exception of IGF-II, Pheterogeneity = 0.02). For prospective studies, the OR for men in the highest versus the lowest fifth of each analyte was 1.29 (95% confidence interval, 1.16-1.43) for IGF-I, 0.81 (0.68-0.96) for IGFBP-1, and 1.25 (1.12-1.40) for IGFBP-3. These associations did not differ significantly by time-to-diagnosis or tumor stage or grade. After mutual adjustment for each of the other analytes, only IGF-I remained associated with risk. Our collaborative study represents the largest pooled analysis of the relationship between prostate cancer risk and circulating concentrations of IGF-I, providing strong evidence that IGF-I is highly likely to be involved in prostate cancer development. Cancer Res; 76(8); 2288-300. ©2016 AACR.

Pappa2 deletion in mice affects male but not female fertility

BACKGROUND

Recent studies have found associations between the gene encoding pregnancy associated plasma protein-A2 (PAPP-A2), a protease of insulin-like growth factor binding protein -5 (IGFBP-5), and measures of female reproductive performance in cattle. The purpose of the present study was to test the effects of Pappa2 deletion on reproduction in mice.

FINDINGS

We measured the fertility and offspring growth of Pappa2 deletion females, and also performed reciprocal matings (i.e., deletion males mated to control females) to control for the effects of offspring genotype. Ovarian and testicular IGFBP-5 levels were measured by Western blotting. As expected, deletion of Pappa2 increased ovarian IGFBP-5 levels. However, Pappa2 deletion in females had no effect on the interval between pairing and the birth of the first litter, the interval between the births of the first and second litters, or litter size. Offspring weight was lower in the offspring of Pappa2 deletion females, but effects of similar magnitude were observed in the offspring of Pappa2 deletion males, suggesting that the effects were due to heterozygosity for the deletion in the offspring. Pappa2 deletion in males had no effect on litter size or the interval between pairing and the birth of the first litter. However, the interval between the births of the first and second litters was significantly longer in deletion males.

CONCLUSIONS

Pappa2 deletion had no effect on female reproductive performance. In contrast, Pappa2 deletion had subtle effects on male fertility, although the underlying mechanism remains to be elucidated.

Cellular proliferation rate and insulin-like growth factor binding protein (IGFBP)-2 and IGFBP-3 and estradiol receptor alpha expression in the mammary gland of dairy heifers naturally infected with gastrointestinal nematodes during development

Mammary ductal morphogenesis during prepuberty occurs mainly in response to insulin-like growth factor-1 (IGF-1) and estradiol stimulation. Dairy heifers infected with gastrointestinal nematodes have reduced IGF-1 levels, accompanied by reduced growth rate, delayed puberty onset, and lower parenchyma-stroma relationship in their mammary glands. Immunohistochemical studies were undertaken to determine variations in cell division rate, IGF-1 system components, and estradiol receptors (ESR) during peripubertal development in the mammary glands of antiparasitic-treated and untreated Holstein heifers naturally infected with gastrointestinal nematodes. Mammary biopsies were taken at 20, 30, 40, and 70 wk of age. Proliferating cell nuclear antigen immunolabeling, evident in nuclei, tended to be higher in the parenchyma of the glands from treated heifers than in those from untreated. Insulin-like growth factor binding proteins (IGFBP) type 2 and type 3 immunolabeling was cytoplasmic and was evident in stroma and parenchyma. The IGFBP2-labeled area was lower in treated than in untreated heifers. In the treated group, a maximal expression of this protein was seen at 40 wk of age, whereas in the untreated group the labeling remained constant. No differences were observed for IGFBP3 between treatment groups or during development. Immunolabeling for α ESR (ESR1) was evident in parenchymal nuclei and was higher in treated than in untreated heifers. In the treated group, ESR1 peaked at 30 wk of age and then decreased. These results demonstrate that the parasite burden in young heifers negatively influence mammary gland development, affecting cell division rate and parameters related to estradiol and IGF-1 signaling in the gland.

Mechanisms of obesity-induced gastrointestinal neoplasia

Obesity is among the fastest growing diseases worldwide; treatment is inadequate, and associated disorders, including gastrointestinal cancers, have high morbidity and mortality. An increased understanding of the mechanisms of obesity-induced carcinogenesis is required to develop methods to prevent or treat these cancers. In this report, we review the mechanisms of obesity-associated colorectal, esophageal, gastric, and pancreatic cancers and potential treatment strategies.

Artificial Neural Networks, and Evolutionary Algorithms as a systems biology approach to a data-base on fetal growth restriction

One of the specific aims of systems biology is to model and discover properties of cells, tissues and organisms functioning. A systems biology approach was undertaken to investigate possibly the entire system of intra-uterine growth we had available, to assess the variables of interest, discriminate those which were effectively related with appropriate or restricted intrauterine growth, and achieve an understanding of the systems in these two conditions. The Artificial Adaptive Systems, which include Artificial Neural Networks and Evolutionary Algorithms lead us to the first analyses. These analyses identified the importance of the biochemical variables IL-6, IGF-II and IGFBP-2 protein concentrations in placental lysates, and offered a new insight into placental markers of fetal growth within the IGF and cytokine systems, confirmed they had relationships and offered a critical assessment of studies previously performed.

Impact of targeting insulin-like growth factor signaling in head and neck cancers

The IGF system has been shown to have either negative or negligible impact on clinical outcomes of tumor development depending on specific tumor sites or stages. This review focuses on the clinical impact of IGF signaling in head and neck cancer, the effects of IGF targeted therapies, and the multi-dimensional role of IRS 1/2 signaling as a potential mechanism in resistance to targeted therapies. Similar to other tumor sites, both negative and positive correlations between levels of IGF-1/IGF-1-R and clinical outcomes in head and neck cancer have been reported. In addition, utilization of IGF targeted therapies has not demonstrated significant clinical benefit; therefore the prognostic impact of the IGF system on head and neck cancer remains uncertain.

Kininogen 1 and insulin-like growth factor binding protein 6: candidate serum biomarkers of proliferative vitreoretinopathy

BACKGROUND

The aim was to validate whether kininogen 1 (KNG1) or insulin-like growth factor binding protein 6 (IGFBP-6) are serum biomarkers of proliferative vitreoretinopathy (PVR).

METHODS

Samples from vitreous and corresponding serum samples were collected from patients with PVR. The donor vitreous samples and serum samples from healthy volunteers and volunteers who had undergone vitrectomies for other conditions were used as controls. The samples were subsequently analysed using Western blotting (WB) and enzyme-linked immunosorbent assay.

RESULTS

The Western blotting outcomes indicated both IGFBP-6 and KNG1 could be specifically detected in the vitreous and serum samples of patients with PVR. The concentrations of KNG1 and IGFBP-6 were significantly higher in both vitreous and serum samples from patients with severe PVR than in the samples from patients with moderate PVR. The serum concentrations of KNG1 or IGFBP-6 had decreased by the post-vitrectomy examinations. The receiver operating characteristic (ROC) analyses when the concentrations of IGFBP-6 or KNG1 were greater than 181.4 pg/ml or 441.75 ng/ml, respectively, predicted severe PVR with both a sensitivity and specificity of over 70 per cent. When the concentrations of IGFBP-6 or KNG1 were greater than 98.5 pg/ml or 88.5 ng/ml, respectively, they predicted the PVR prognosis with both a sensitivity and specificity of 80 per cent.

CONCLUSIONS

KNG1 and IGFBP-6 may be candidate serum biomarkers of PVR.

The insulin-like growth factor system in bone: basic and clinical implications

The insulin-like growth factor (IGF) regulatory system is critical for skeletal growth and maintenance. Initially there was great hope that the recombinant IGFs might be used clinically for disorders ranging from short stature to fracture repair and osteoporosis. Although this potential was not realized, basic and translational studies have continued, providing significant insights into the role of this family of growth factors in skeletal homeostasis and the pathophysiology of several bone disorders. This article reviews the importance of the IGF regulatory system in skeletal growth and maintenance.

Androgen mediated translational and postranslational regulation of IGFBP-2 in androgen-sensitive LNCaP human prostate cancer cells

The insulin-like growth factor (IGF) axis is associated intimately with prostate cancer (PCa) development, growth, survival and metastasis. In particular, increased levels of IGFBP-2 expression are associated with advanced PCa, bone metastasis, and the development of castrate resistant PCa. Previously, we reported that androgen treatment decreased intracellular and extracellular IGFBP-2 in the androgen sensitive (AS) PCa cell line, LNCaP. Nonetheless, the mechanism by which androgen treatment decreases expression of IGFBP-2 is not clear. Since elevated IGFBP-2 is associated with a variety of advanced cancers, including PCa, coupled with the fact that hormone ablation is the customary treatment modality for advanced PCa, a complete understanding of the influence of androgens on IGFBP-2 expression is essential. Androgen treatment initially increased steady state IGFBP-2 mRNA levels in LNCaP cells. Extended androgen treatment on LNCaP resulted in a time-dependent decrease in both steady state IGFBP-2 mRNA and protein. Polysomal mRNA analysis showed no difference in IGFBP-2 association with a given fraction; however, Q-PCR revealed less IGFBP-2 mRNA in each androgen-treated fraction. In addition, there was an overall decrease in polysome mRNA after androgen treatment. Extracellular proteolysis of IGFBP-2 was prevented in the presence of serine protease inhibitors. These data indicate that androgen acts via multiple levels to down-regulate IGFBP-2 in LNCaP PCa cells.

Novel actions of IGFBP-3 on intracellular signaling pathways of insulin-secreting cells

Understanding mechanisms underlying apoptotic destruction of insulin-secreting cells is critical to validate therapeutic targets for type 1 diabetes mellitus. We recently reported insulin-like growth factor binding protein-3 (IGFBP-3) as a novel mediator of apoptosis in insulin-secreting cells. In light of emerging IGF-independent roles for IGFBP-3, we investigated the mechanisms underlying actions of the novel, recombinant human mutant G(56)G(80)G(81)-IGFBP-3, which lacks intrinsic IGF binding affinity. Using the rat insulinoma RINm5F cell line, we report the first studies in insulin-secreting cells that IGFBP-3 selectively suppresses multiple, key intracellular phosphorelays. By immunoblot, we demonstrate that G(56)G(80)G(81)-IGFBP-3 suppresses phosphorylation of c-raf-MEK-ERK pathway and p38 kinase in time-dependent and dose-dependent manners. SAPK/JNK signaling was unaffected. These data delineate several novel intracellular sites of action for IGFBP-3 in insulin-secreting cells.

Insulin-like growth factor binding protein-3 mediates cytokine-induced mesangial cell apoptosis

Mesangial cells are critical for glomerular filtration. Mesangial cell dysfunction, the hallmark of diabetic nephropathy, results from disordered mesangial growth induced by cytokines, abnormal hemodynamic influence, and metabolic factors associated with chronic hyperglycemia. Insulin-like growth factors (IGFs) and their high affinity binding proteins (IGFBPs) exert major actions on mesangial cell survival, but their underlying mechanisms remain unclear. In light of emerging IGF-independent roles for IGFBP-3, we investigated IGFBP-3 actions during mesangial cell apoptosis induced by cytokine or high glucose concentration. Quantified by DNA fragmentation ELISA and Annexin V flow cytometry, apoptosis occurred in rat mesangial cells (RMC) exposed to 2 microg/mL IGFBP-3 for 24 h under high ambient or standard glucose. Anti-sense IGFBP-3 oligo at 10 microg/mL significantly inhibited apoptosis induced by 100 ng/mL TNF-alpha, serum-free conditions, or high (25 mM) glucose. Increased IGFBP-3 release associated with high ambient glucose or TNF-alpha was inhibited by pre-treatment with anti-sense oligo. Under serum-free conditions, recombinant human IGFBP-3 blocked Akt phosphorylation at threonine 308 (pThr308), whereas anti-sense oligo treatment was associated with enhanced pThr308 activity. In summary, these data support a novel mechanism for TNF-alpha-induced mesangial cell apoptosis mediated by IGFBP-3 and present regulation of pThr308 activity as a novel mechanism underlying IGFBP-3 action.

The Twisted gastrulation family of proteins, together with the IGFBP and CCN families, comprise the TIC superfamily of cysteine rich secreted factors

AIMS

To analyse the similarities between the Twisted gastrulation (TSG) proteins known to date; in addition, to determine phylogenetic relations among the TSG proteins, and between the TSGs and other protein families--the CCN (for example, CCN2 (CTGF), CCN1 (CYR61), and CCN3 (NOV)) and IGFBP (insulin-like growth factor binding protein) families.

METHODS

TBLASTN and FASTA3 were used to identify new tsg genes and relatives of the TSG family. The sequences were aligned with ClustalW. The predictions of sites for signal peptide cleavage, post-translational modifications, and putative protein domains were carried out with software available at various databases. Unrooted phylogenetic trees were calculated using the UPGMA method.

RESULTS

Several tsg genes from vertebrates and invertebrates were compared. Alignment of protein sequences revealed a highly conserved family of TSG proteins present in both vertebrates and invertebrates, whereas the slightly less well conserved IGFBP and CCN proteins are apparently present only in vertebrates. The TSG proteins display strong homology among themselves and they are composed of a putative signal peptide at the N-terminus followed by a cysteine rich (CR) region, a conserved domain devoid of cysteines, a variable midregion, and a C-terminal CR region. The most striking similarity between the TSGs and the IGFBP and CCN proteins occurs in the N-terminal conserved cysteine rich domain and the characteristic 5' cysteine rich domain(s), spacer region, and 3' cysteine rich domain structure.

CONCLUSION

The family of highly conserved TSG proteins, together with the IGFBP and CCN families, constitute an emerging multigene superfamily of secreted cysteine rich factors. The TSG branch of the superfamily appears to pre-date the others because it is present in all species examined, whereas the CCN and IGFBP genes are found only in vertebrates.

The IGF/IGFBP system in CNS malignancy

The insulin-like growth factor (IGF) system includes IGF-I and IGF-II, the type I and type II IGF receptors, and specific IGF binding proteins (IGFBP-1 to IGFBP-6). These factors regulate both normal and malignant brain growth. Enhanced expression of IGF-I and IGF-II mRNA transcripts has been demonstrated in gliomas, meniningiomas, and other tumours. Abnormal imprinting of IGF-II occurs in gliomas, medulloblastomas, and meningiomas. Both types of IGF receptor are expressed in gliomas and, in particular, the type I IGF receptor appears to be upregulated in malignant brain tissue. Antisense IGF-I receptor mRNA induces an antitumour response, resulting in complete brain tumour regression. Clinical trials for the treatment of brain tumours in humans based on a gene transfer protocol using IGF-I receptor antisense are under way. All six IGFBPs are expressed to a variable extent in brain tumours. High concentrations of IGFBP-2 are found in cerebrospinal fluid from patients with malignant central nervous system tumours; therefore, IGFBP-2 might be a useful marker for these tumours. IGFBP-4 appears to be a negative regulator of tumour proliferation. Both in vitro and in vivo experiments suggest that the IGF system represents an important target for the treatment of malignant central nervous system tumours and the ongoing trials should provide valuable information for future therapeutic approaches.