Role of insulin-like growth factor binding proteins (IGFBPs) in breast cancer proliferation and metastasis

Cancers of the breast, prostate, and lung commonly metastasize to the bone resulting in osteolysis, pathologic fracture, pain and significant clinical morbidity. To date, the reason for such selectivity in the site of metastasis remains largely unknown. The bone is a rich source of many chemokines and growth factors, including: insulin-like growth factor (IGF) I and II, transforming growth factor-β (TGF-β), interleukins, and tumour necrosis factor-α (TNF-α) [1]. We propose that exposure of breast cancer cells to the bone microenvironment results in alterations in gene expression that favour the growth and proliferation of tumour cells in the bone. To investigate this hypothesis, MDA-MB-231 breast carcinoma cells were exposed to bone-derived conditioned media (BDCM) generated by culturing fetal rat calvaria for 24 h under serum free conditions. Using cDNA microarray technology, we have identified the insulin-like growth factor family of binding proteins (IGFBPs) as genes whose expression profiles are consistently and significantly altered with exposure to this simulated bone environment in vitro, when compared to untreated controls. Our data suggests that the upregulation of IGFBP-3 seen with exposure to the bone microenvironment is directly linked to an increase in TGF-β mediated cell proliferation. Furthermore, this process appears to be functioning through an IGF-independent mechanism. This revised version was published online in July 2006 with corrections to the Cover Date.     

直肠癌患者手术治疗前后血清IGF-I、CEA和TSGF检测的临床意义

目的:探讨了直肠癌患者手术治疗前后的血清IGF-I、CEA和TSGF水平的变化及临床意义.方法:分别应用放免法和化学法对36例直肠癌患者进行了血清IGF-I、CEA和TSGF水平的检测,并与35名正常健康人作比较.结果:手术前直肠癌患者血清IGF-I、CEA和TSGF水平非常显著地高于正常人 (P＜0.01),手术治疗一年后复发组明显地高于未复发组(P＜0.01).结论:检测直肠癌患者血清IGF-I、CEA和TSGF水平的变化与直肠癌患者的病情和预后密切相关,具有重要的临床价值.     

Prenatal expression of growth hormone receptor/binding protein and insulin-like growth factor-I (IGF-I) in the enamel organ

Immunohistochemistry was used to study the ontogeny of GH receptor/binding protein (GHR/BP) and IGF-I from the 13-day-old embryo (E13) to the E19 rat fetus in the developing incisor and molar. Analysis of serial sections revealed diffuse staining of GHR/BP and IGF-I at the bud and early cap stages within both the mesenchyme of the dental papilla and the ectodermal-erived enamel organ. Just before transition to the cap stage, immunoreactivity of GHR/BP and IGF-I increased in the epithelial bud and extended to the condensed dental mesenchyme. At the cap stage, the dental epithelium showed an intense expression of GHR/BP and IGF-I, whereas the dental mesenchymal cells showed very weak staining. The inner enamel epithelium and the outer enamel epithelium were positive for both GHR/BP and IGF-I in the bell stage. Differentiating ameloblasts, odontoblasts and the secretory ameloblasts and odontoblasts continued to express GHR/BP and IGF-I in incisors. These findings support the premise that growth hormone and IGF-I may play a role in embryonic tooth development by regulating the epithelial-mesenchymal interactions that influence events in growth and cytodifferentiation.     

Antiproliferative effects and insulin-like growth factor-I expression in Balb-C 3T3 fibroblasts after treatment with somatostatin and gonadotropin-releasing hormone analogs

The present study was aimed to compare antiproliferative effects of somatostatin (SS) and gonadotropin-releasing hormone analogs (GnRHa) on a fibroblast cell line. Proliferation index, cell count, viability of the cells and insulin-like growth factor-I (IGF-I) immunoreactivity were determined after treatment with either SS (100 microM/ml), GnRHa (35 nM/ml) or SS and GnRHa of Balb-C 3T3 mouse fibroblasts. It was found that the proliferation index, cell count, viability and IGF-I immunoreactivity were not affected by GnRHa treatment as compared with no treatment (p > 0.05). Application of SS to the fibroblasts resulted in a significant reduction in proliferation index, cell count, and IGF-I immunoreactivity as compared with GnRHa treatment and no treatment, but it had no effect on cell viability. The labelling index in SS-treated cells was significantly reduced as compared with combined treatment with SS and GnRHa. In conclusion, a direct effect of GnRHa on fibroblast cells in culture could not be demonstrated. SS had direct inhibitory effects on cell proliferation possibly via inhibition of IGF-I effects without affecting cell viability.     

A simplified method of analysis of cell-conditioned medium forInsulin-like Growth Factor-I (IGF-I) activity

To facilitate further investigation of the relationship between IGF-I and IGF binding proteins (IGFBPs) and their effect on myogenic satellite cells, we developed a procedure for rapid screening of cell-conditioned medium for free IGF-I. This method involves the adaptation and implementation of a DNA vacuum blotting manifold, which allows detection of a broad range of IGF-I and is rather sensitive (detection < 10 ng) when compared to western immunoblots. Additionally, this dot-blot method requires less than 40 minutes prior to the addition of the blotto-antibody mixture. Application of the dot-blot method for analysis of free IGF-I levels in conditioned medium samples offers an alternative to the use of western immunoblots, and may be used in initial screening of large numbers of conditioned medium samples.     

前列腺癌患者血清IGF-I、PRL及SE-cad测定的临床意义

目的：探讨前列腺癌患者血清IGF-Ⅰ、PRL及SE-cad水平的变化及临床意义。方法：血清IGF-Ⅰ采用放射免疫分析;fPSA及PRL采用化学发光法;血清SE-cad采用酶联免疫分析法。结果：前列腺增生组患者血清IGF-Ⅰ水平较对照组升高显著（P〈0.05）;血清PRL含量也较对照组显著升高（P〈0.05）;SE-cad浓度其测定数值也存在显著性差异（P〈0.05）。而前列腺癌患者组血清IGF-Ⅰ水平较对照组升高更为显著（P〈0.01）;血清PRL含量也较对照组升高极其显著（P〈0.01）;SE-cad浓度其测定数值升高同样非常显著（P〈0.01）。灵敏度分析表明,fPSA＋IGF-Ⅰ和fPSA＋SE-cad两组灵敏度显著高于fPSA单项测定组;fPSA＋PRL组灵敏度略低,但P〉0.05。特异性分析则fPSA＋SE-cad组fPSA单项测定组显著增高（P〈0.05）,fP-SA＋PRL降低明显,fPSA＋IGF-Ⅰ组与单项组差异并不显著（P〉0.05）。结论：血清IGF-Ⅰ、PRL及SE-cad水平的变化与前列腺癌的发生关系密切,与fPSA的联合测定可提高诊断的灵敏度及特异性,有助于前列腺癌的辅助诊断。     

Regulation of pancreatic inflammation by connective tissue growth factor (CTGF/CCN2)

Pancreatitis is caused by long‐term heavy alcohol consumption, which results in injury and death of pancreatic acinar cells (PAC). The PAC play a pivotal role in mediating early inflammatory responses but the underlying mechanisms remain poorly understood. Treatment of C57BL/6 mice with ethanol and cerulein resulted in increased staining for acinar interleukin‐1β (IL‐1β), chemokine (C‐C motif) ligand 3 (CCL3), or connective tissue growth factor (CTGF/CCN2) by Day 16 and this was associated with increased infiltration of F4/80‐positive macrophages and increased expression of pancreatic CTGF/CCN2 mRNA. Compared with wild‐type Swiss Webster mice, ethanol treatment of pan‐green fluorescent protein (GFP)‐CTGF/CCN2 transgenic mice caused enhanced acinar staining for GFP or CTGF/CCN2 and a significant increase in pancreatic infiltration of F4/80‐positive macrophages or NIMP‐R14‐positive neutrophils. Treatment of primary mouse PAC or the rat AR42J PAC line with ethanol or CTGF/CCN2 resulted in enhanced expression of IL‐1β or CCL3. Conditioned medium from CTGF/CCN2‐treated AR42J cells induced chemotaxis in NR8383 macrophages and this response was abrogated in a dose‐dependent manner by addition of BX471, an inhibitor of chemokine (C‐C motif) receptor 1. These results reveal that acinar CTGF/CCN2 plays a novel role in alcohol‐induced inflammatory processes in the pancreas by increasing infiltration of macrophages and neutrophils and increasing acinar production of inflammatory mediators such as IL‐1β or CCL3. The early production of CTGF/CCN2 by PAC to drive inflammation is distinct from its previously reported production by pancreatic stellate cells to drive fibrosis at later stages of pancreatic injury.     

Growth hormone (GH), insulin-like growth factors (IGFs), and IGF-binding protein-3 (IGFBP-3) in a child with Proteus syndrome

Proteus syndrome is a congenital hamartomatous disorder characterized by partial overgrowth involving all germ layers. A somatic mutation model has been proposed since familial cases are extremely rare. We report on a 3-year-old girl with typical manifestations of Proteus syndrome, including local, asymmetric hypertrophy of various parts of the body. Total body length was reduced. Serum levels of IGF-I and especially IGF-II and their major growth hormone dependent binding protein (IGFBP-3) were significantly reduced, although growth hormone secretion after a pharmacological stimulus was normal. In vitro studies of fibroblasts derived from hypertrophied tissue showed normal IGF-I production and somewhat reduced IGF-II and IGFBP-3 production as compared to normal human skin fibroblasts. Affinity cross-linking experiments showed that fibroblasts of the affect tissue in Proteus syndrome produced an unusual pattern of IGF bindings proteins containing large amounts of an IGFBP with high affinity to IGF-II. The data suggest that IGF production is generally disturbed in Proteus syndrome with imbalanced levels of specific IGFBP in affected tissue. © 1994 Wiley-Liss, Inc.     

Synergistic effects of 1,25-Dihydroxyvitamin D3 and TGF-beta1 on the production of insulin-like growth factor binding protein 3 in human bone marrow stromal cell cultures

1,25-Dihydroxyvitamin D3 (calcitriol), transforming growth factor-beta (TGF-beta), and insulin-like growth factors (IGFs) are all important bone regulatory factors known to affect proliferation and differentiation of human bone-forming cells (osteoblasts). We have previously shown that TGF-beta1 increased IGF-I and IGF-binding protein (IGFBP)-3 production in human bone marrow stromal (hMS) osteoblast progenitors and calcitriol stimulated IGFBP-3 and IGFBP-4 production. As interaction between signaling pathways of these factors has been reported, the present study aimed at examining the concerted actions on components of the IGF-system. We report that co-treatment with TGF-beta1 and calcitriol resulted in a synergistic increase in IGFBP-3 production, thereby suggesting that the effects of these factors on hMS osteoblast differentiation may involve the observed increase in IGFBP-3.     

检测血清IGF-1和IGFBP-3对儿童生长激素缺乏症的诊断价值

目的：探讨血清胰岛素样生长因子-1(IGF-1)和胰岛素样生长因子结合蛋白-3(IGFBP-3)浓度在诊断生长激素缺乏症(GHD)患儿中的应用价值。方法：用免疫放射分析检测38例GHD患儿和42例对照儿童的血清IGF-1和IGFBP-3,同时进行生长激素(GH)激发试验,用化学发光法检测GH,对两组结果进行比较。结果：GHD组患儿IGF-1和IGFBP-3均显著低于对照组儿童,且在GH激发试验中,GH的增加值也明显低于对照组。结论：检测血清中的IGF-1和IGFBP-3,对诊断GHD儿童具有重要价值。     

Pathological evaluation of uterine leiomyomas treated with gonadotropin-releasing hormone agonist (GnRH-a) therapy: role of mast cells and a possible mechanism of GnRH-a resistance in leiomyomas

Gonadotropin-releasing hormone agonist (GnRH-a) therapy is frequently applied to reduce the volume of uterine leiomyomas (UL). In addition, the possible relationship between mast cells (MC) within UL and the development of UL has been suggested, but the role of MC in UL remains to be determined. UL with or without GnRH-a therapy in 121 premenopausal patients were reviewed. The number of MC was evaluated between the two groups, immunohistochemistry was done for insulin-like growth factor-I (IGF-I), and the association between the IGF-I immunoreactivity in UL and the GnRH-a therapy was analyzed. The number of MC significantly increased in UL in GnRH-a therapy, while IGF-I immunoreactivity was significantly reduced in smooth muscle cells of these UL. Furthermore, IGF-I immunoreactivity in MC was inversely correlated with the size reduction rate of UL in GnRH-a therapy. Although GnRH-a therapy is considered to reduce the size of UL transiently, the regression of UL was in part hampered by the increased IGF-I secretion from the increased MC after GnRH-a therapy. Therefore, the more the IGF-I secretion from MC in UL increases, the less effective the GnRH-a therapy is on the size reduction of UL. Thus, the present study may provide an explanation of the possible mechanism of GnRH-a resistance in UL.     

Nuclear translocation of fibroblast growth factor receptor 3 and its significance in pancreatic cancer

Nuclear translocation of fibroblast growth factor receptor 3 (FGFR3) was previously observed in some kinds of cancer. However, whether the phenomenon occurs in pancreatic cancer (PC), a malignancy with very dismal prognosis, remains unknown. In the present study, FGFR3 expression was firstly detected by Western blot and immunohistochemical staining in specimens of PC. Then, its correlations with clinicopathologic features and patient survival were evaluated. It was shown that FGFR3 was highly expressed in all the nuclear extracts, but in only one out of four whole tissue lysates, of tumor tissues, in contrast to those of non-tumor ones. Using immunohistochemistry, nuclear expression of FGFR3 was found to mainly locate in tumor cells, and was significantly associated with N stage. Furthermore, high FGFR3 nuclear expression was revealed to be associated with poor overall and disease-free survival in univariate analysis. For overall survival in the whole cohort and disease-free survival in patients with curative resection, high nuclear expression of FGFR3 was significant or marginally significant in multivariate analysis. However, its cytoplasmic expression was not related to clinical, pathologic variables and prognosis. These data suggest that nuclear translocation of FGFR3 is frequent and carries clinicopathologic as well as prognostic significances in PC.     

A cross-sectional analysis of the associations between adult height,BMI and serum concentrations of IGF-I and IGFBP-1 -2 and -3 in the European Prospective Investigation into Cancer and Nutrition (EPIC)

Background: Height and BMI are risk factors for several types of cancer and may be related to circulating concentrations of insulin-like growth factor-I (IGF-I), a peptide associated with increased cancer risk.

Aim: To assess the associations between height, BMI and serum concentrations of IGF-I and IGF binding protein (IGFBP)-1, -2 and -3.

Subjects and methods: This cross-sectional analysis included 1142 men and 3589 women aged 32–77 years from the multi-centre study, the European Prospective Investigation of Cancer and Nutrition (EPIC).

Results: In men, there was a positive association between height and IGF-I; each 10 cm increment in height was associated with an increase in IGF-I concentrations of 4.3% (95% confidence interval (CI): 1.3–7.5%, p for trend = 0.005), but this association was not statistically significant for women (0.9%, 95% CI: ? 0.7 to 2.6%, p for trend = 0.264). In both men and women, the association between IGF-I and BMI was non-linear and those with a BMI of 26–27 kg/m² had the highest IGF-I concentration. BMI was strongly inversely related to concentrations of IGFBP-1 and IGFBP-2 in men and in women (p for trend for all < 0.001).

Conclusion: Height and BMI are associated with IGF-I and its binding proteins, which may be mechanisms through which body size contributes to increased risk of several cancers.     

Circulating insulin-like growth factor I and cognitive function: Neuromodulation throughout the lifespan

Insulin-like growth factor I (IGF-I) is central to the somatotropic (growth hormone) axis. It promotes tissue growth and continues to have anabolic effects in adulthood. Accumulating evidence from the last decade, however, reveals that circulating levels of IGF-I also significantly affects cognitive brain function. Specifically, the decline of serum IGF-I might be associated with the age-related cognitive decline in elderly people. Moreover, psychiatric and neurological conditions characterized by cognitive impairment may be characterized by altered levels of IGF-I. Some evidence is emerging that interventions that target the GH/IGF-I axis may improve cognitive functioning, at least in deficient states. As there is evidence linking high serum IGF-I levels with cancer risk, these interventions should be carefully evaluated. On a cellular and molecular level, IGF-I may be a crucial component of neural homeostasis since disturbed IGF-I input is inevitably linked to perturbed function. Consistent with this, all nerve cells are potential targets of IGF-I actions, including neurons, glia, endothelial, epithelial, and perivascular cells. Indeed, many key cellular processes in the brain are affected by IGF-I's neurotrophic and modulatory actions. We review the regulation by IGF-I of neurotransmission and neuronal plasticity and conclude that serum IGF-I is an important mediator of neuronal growth, survival and function throughout the lifespan. The role of IGF-I in synaptic plasticity render its neurotrophic potential a key target for remediating the cognitive impairment associated with a range of neurological conditions.     

Regulation of Insulin-Like Growth Factor-I (IGF-I) Delivery by IGF Binding Proteins and Receptors

Delivery of growth factors via the bloodstream for the treatment of various diseases is regulated in part by interactions with cell surface binding elements. Understanding the kinetics of growth factor binding and transport by cells would, therefore, be advantageous. This report quantifies the binding, internalization, and transport of insulin-like growth factor-I (IGF-I) across bovine aortic endothelial cells (BAEC) cultured in vitro. Binding analysis indicated that IGF binding proteins (IGFBPs), primarily localized with the extracellular matrix, were the primary IGF-I binding elements in our system, with twice as many binding sites (8.0 ± 1.9 × 10⁴ per cell) as IGF-I receptors (IGF-IR) (3.9 ± 0.6 × 10⁴ per cell). Internalization of IGF-I by IGF-IR, but not IGFBPs, was detected, however both receptor and IGFBP binding were shown to inhibit rather than enhance the transport of intact IGF-I, albeit in different ways. IGFBPs retained IGF-I in the apical region while IGF-IR binding led to protein degradation. Based on our computational modeling and experimental data, we hypothesize that IGFBPs could function as a reservoir for IGF-I, sequestering it for later release and transport, and that this reservoir function of the IGFBPs could be used to promote controlled localized delivery of IGF-I.     

Polymorphisms of insulin-like growth factor-1 (IGF-1) and IGF-1 receptor (IGF-1R) contribute to pathologic progression in childhood IgA nephropathy

Previous studies have suggested that insulin-like growth factor-1 (IGF-1) signaling might play an important role in renal fibrosis and regulation of the proliferation of mesangial cells and podocytes. We conducted the present study to investigate association between single nucleotide polymorphisms (SNPs) of IGF-1 (IGF-1) and IGF-1 receptor (IGF-1R) genes and childhood immunoglobulin (Ig) A nephropathy (IgAN). We analyzed five SNPs of IGF-1 and IGF-1R in 188 pediatric IgAN patients and in 263 healthy controls. We compared variations in SNPs in several sets of IgAN subgroups that were designated based on the presence of nephrotic range proteinuria (>40 mg/m² per h), podocyte foot process effacement, and pathological progression. Genotyping of IgAN patients and controls revealed differences in IGF-1R rs2229765. Moreover, the rs2195239, rs978458, and rs1520220 SNPs of IGF-1 showed significant association with pathological progression. Thus, in the present study, we observed associations between the IGF-1/1R pathway, susceptibility to IgAN, and the pathologic progression of IgAN.     

Differential distribution of fibroblast growth factor (FGF)-7 and FGF-10 in L-arginine-induced acute pancreatitis

The regenerative process of the pancreas after acute pancreatitis (AP) is characterized by acinar and ductal cell proliferation with synthesis and transient deposition of extracellular matrices. Various growth factors were reported to be highly expressed in AP, but their regulation has not yet been clarified. Fibroblast growth factor (FGF)-7, also known as keratinocyte growth factor (KGF), and FGF-10 are members of the FGF family and show high structural homology and similar biological characteristics. Both are mainly synthesized by mesenchymal cells and stimulate epithelial cells via KGF receptor (KGFR) which is a splice variant of FGFR-2. In the present study, we attempted to immunohistochemically determine the localization of FGF-7 and FGF-10 in pancreatic tissues of an L-arginine-induced rat pancreatitis model. Furthermore, highly specific KGFR antibodies were prepared and used for Western blot analysis and immunohistochemistry. In the normal pancreas, FGF-7 was localized in alpha cells of islets, but FGF-10 was not detected. KGFR was also localized in islet cells, ductal cells, and centroacinar cells in the normal pancreas. In the pancreatic tissues of rats with L-arginine-induced pancreatitis, FGF-7 was localized in alpha cells, whereas FGF-10 was expressed in vascular smooth muscle cells (VSMCs). KGFR was not expressed in centroacinar cells and its level decreased after L-arginine treatment. However, KGFR was detected instead in some acinar cells and VSMCs in addition to islet cells. These findings suggest that FGF-7 and FGF-10 contribute to the regeneration and differentiation of acinar cells and angiogenesis in AP through KGFR.     

High nuclear poly-(ADP-ribose)-polymerase expression is prognostic of improved survival in pancreatic cancer

Klauschen F, von Winterfeld M, Stenzinger A, Sinn B V, Budczies J, Kamphues C, Bahra M, Wittschieber D, Weichert W, Striefler J, Riess H, Dietel M & Denkert C
(2012) Histopathology  61, 409–416 High nuclear poly‐(ADP‐ribose)‐polymerase expression is prognostic of improved survival in pancreatic cancer Aims: Poly‐(ADP‐ribose)‐polymerases (PARPs) act as post‐translational modifiers of proteins that are mainly involved in the DNA repair machinery, and have recently been shown to be predictive of pathologically complete remission after chemotherapy in breast cancer. In the pancreas, PARP expression has so far only been studied in inflammatory conditions. Therefore, in this study, we investigated the relevance of PARP in pancreatic cancer. Methods and results: Cytoplasmic and nuclear PARP expression was assessed by immunohistochemistry in a population‐based cohort of 178 adenocarcinomas of the pancreas and correlated with clinicopathological parameters. We found that low‐level nuclear expression of PARP is associated with a poor prognosis (median survival 9.6 versus 14.5 months, P = 0.004). Conclusions: Our analysis shows that nuclear PARP is an independent prognostic marker with respect to standard clinicopathological parameters. These results suggest that PARP should be further explored as a predictive factor with respect to conventional chemotherapy and concepts of PARP inhibitor therapy in pancreatic cancer.