Expression Of Insulin-like Growth factor-II Research Articles

Determinants of IGF-II influencing stability, receptor binding and activation

Insulin like growth factor II (IGF-II) is involved in metabolic and mitogenic signalling in mammalian cells and plays important roles in normal fetal development and postnatal growth. It is structurally similar to insulin and binds not only with high affinity to the type 1 insulin-like growth factor receptor (IGF-1R) but also to the insulin receptor isoform A (IR-A). As IGF-II expression is commonly upregulated in cancer and its signalling promotes cancer cell survival, an antagonist that blocks IGF-II action without perturbing insulin signalling would be invaluable. The high degree of structural homology between the IR and IGF-1R makes selectively targeting either receptor in the treatment of IGF-II-dependent cancers very challenging. However, there are sequence differences between insulin and IGF-II that convey receptor selectivity and influence binding affinity and signalling outcome. Insulin residue YB16 is a key residue involved in maintaining insulin stability, dimer formation and IR binding. Mutation of this residue to glutamine (as found in IGF-II) results in reduced binding affinity. In this study we sought to determine if the equivalent residue Q18 in IGF-II plays a similar role. We show through site-directed mutagenesis of Q18 that this residue contributes to IGF-II structural integrity, selectivity of IGF-1R/IR binding, but surprisingly does not influence IR-A signalling activation. These findings provide insights into a unique IGF-II residue that can influence receptor binding specificity whilst having little influence on signalling outcome.

Effect of a copper intrauterine device on HLA-G and IGF-II levels during pregnancy

ObjectiveAn intrauterine device (IUD) is one of the most effective reversible contraceptive methods currently available. Women who use IUDs may become pregnant, albeit rarely, and many such women continue to use IUDs. Because it is difficult to remove or it may cause miscarriage. This study measured the changes in human leucocyte antigen-G (HLA-G) and insulin-like growth factor II (IGF-II) levels in the decidua and villi to explore the effect of a copper IUD on embryonic development. DesignA total of 54 samples of decidual and villus tissue were collected from pregnant women with IUDs (27 samples) or without IUDs (27 samples). Hematoxylin-eosin staining was used to identify morphological characteristics. Immunohistochemistry was used to detect HLA-G and IGF-II; the protein expression levels were measured via Western blotting. ResultsHLA-G was expressed on the membranes of trophoblasts of villus tissues and the glandular epithelium, and in stromal cells of decidual tissues, in both the IUD and control groups. IGF-II was expressed in the glandular epithelium and cytoplasm of trophoblasts and decidual cells in both groups. Compared to the control group, IGF-II expression was significantly reduced in villus tissues of the IUD group (p < 0.05). The mean sac diameter was significantly positively correlated with IGF-II expression in the villi (p < 0.05). ConclusionsA copper IUD may affect embryonic development by regulating the expression of villus IGF-II.

The expression of platelet-derived growth factor, epidermal growth factor, and insulin-like growth factor-II in patients with polycystic ovary syndrome and its correlation with pregnancy outcomes.

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder with complex pathogenesis. This study aimed to analyze the expression of platelet-derived growth factor (PDGF), epidermal growth factor (EGF), and insulin-like growth factor-II (IGF-II) in patients with PCOS and its correlation with pregnancy outcomes. A total of 104 PCOS patients admitted to the Cangzhou Central Hospital from January 2015 to February 2018 were selected as the PCOS group, and 92 healthy pregnant women who received health examinations in the hospital during the same period were selected as the control group. Levels of PDGF, EGF, and IGF-II in serum were detected. The expression of PDGF, EGF, and IGF-II in different populations were compared. Age at pregnancy, body mass index (BMI), waist-to-hip ratio before pregnancy, parity, family history of hypertension, family history of diabetes, and serological indicators of pregnant women in the PCOS group were collected, such as follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), fasting insulin (INS), and free testosterone index (FTI). Multivariate logistic regression was used to analyze the risk factors that affect the pregnancy outcomes of PCOS patients. The expression levels of PDGF, EGF, and IGF-II in the PCOS group were significantly higher than those in the control group (P<0.05). Among 76 pregnant PCOS patients, 34 cases had adverse pregnancy outcomes and 42 did not. Age at pregnancy, BMI before pregnancy, waist-to-hip ratio before pregnancy, LH, INS, FTI, PDGF, EGF, and IGF-II expression levels were positively correlated with the pregnancy outcome of PCOS patients (P<0.05). The BMI before pregnancy, waist-to-hip ratio before pregnancy, INS, FTI, and expression levels of PDGF, EGF, and IGF-II were revealed as independent risk factors that affect the pregnancy outcomes of PCOS patients (P<0.05). The expression levels of PDGF, EGF, and IGF-II are high in PCOS patients. The BMI, waist-to-hip ratio before pregnancy, INS, FTI, and the expression levels of PDGF, EGF, IGF-II are independent risk factors that affect the pregnancy outcomes of PCOS patients. Corresponding measures should be actively taken for PCOS patients with high-risk factors to improve both maternal and infant outcomes.

Alteration of Metabolic Conditions Impacts the Regulation of IGF-II/H19 Imprinting Status in Prostate Cancer.

Simple SummaryInsulin-like growth factor II (IGF-II) is a potent growth factor implicated in several cancer types. The IGF-II gene shares its locus with the long non-coding RNA, H19. IGF-II/H19 is an imprinted gene—a phenomenon where only the maternal copy is expressed. The silencing of the paternal copy is lost in many cancer types—including prostate. Our in vitro findings show it is possible to disrupt imprinting through the alteration of metabolic conditions, with changes occurring at the molecular level only. Comparing with prostate tissue samples we additionally found a positive correlation to exist between IGF-II and H19 mRNA expression, which was further confirmed by in silico data from the Cancer Genome Atlas.Prostate cancer is the second major cause of male cancer deaths. Obesity, type 2 diabetes, and cancer risk are linked. Insulin-like growth factor II (IGF-II) is involved in numerous cellular events, including proliferation and survival. The IGF-II gene shares its locus with the lncRNA, H19. IGF-II/H19 was the first gene to be identified as being “imprinted”—where the paternal copy is not transcribed—a silencing phenomenon lost in many cancer types. We disrupted imprinting behaviour in vitro by altering metabolic conditions and quantified it using RFLP, qPCR and pyrosequencing; changes to peptide were measured using RIA. Prostate tissue samples were analysed using ddPCR, pyrosequencing and IHC. We compared with in silico data, provided by TGCA on the cBIO Portal. We observed disruption of imprinting behaviour, in vitro, with a significant increase in IGF-II and a reciprocal decrease in H19 mRNA; the increased mRNA was not translated into peptides. In vivo, most specimens retained imprinting status apart from a small subset which showed reduced imprinting. A positive correlation was seen between IGF-II and H19 mRNA expression, which concurred with findings of larger Cancer Genome Atlas (TGCA) cohorts. This positive correlation did not affect IGF-II peptide. Our findings show that type 2 diabetes and/or obesity, can directly affect regulation growth factors involved in carcinogenesis, indirectly suggesting a modification of lifestyle habits may reduce cancer risk.

Insulin-like growth factor-II overexpression accelerates parthenogenetic stem cell differentiation into cardiomyocytes and improves cardiac function after acute myocardial infarction in mice

BackgroundParthenogenetic stem cells (PSCs) are a promising source of regenerated cardiomyocytes; however, their application may be limited without a paternal genome. Insulin-like growth factor-II (IGF-II), a paternally expressed growth hormone, is critical in embryonic differentiation. This study investigated whether forced expression of IGF-II in PSCs can accelerate their differentiation.MethodsOverexpression and re-knockdown of IGF-II in PSCs were performed to investigate the role of IGF-II in PSC differentiation. The derivatives of PSCs with different IGF-II manipulations were transplanted into infarcted murine hearts to investigate the role of IGF-II in cardiomyocyte differentiation in vivo.ResultsData showed that the expression of cardiac troponin T and troponin I in IGF-II-PSC outgrowths preceded that of parental PSC outgrowths, suggesting that IGF-II can accelerate PSC differentiation into cardiac lineage. Overexpression of IGF-II accelerated PSC differentiation towards cardiomyocytes while inhibiting PSC proliferation via the IGF-II/IGF1R signaling. Similar to that observed in cardiac marker expression, on differentiation day 24, IGF-II-PSCs showed PCNA and cyclin D2 expression comparable to juvenile mouse cardiomyocytes, showing that IGF-II-PSCs at this stage possess differential and proliferative properties similar to those of juvenile cardiomyocytes. Moreover, the expression pattern of cardiac markers in IGF-II-overexpressing PSC derivatives resembled that of juvenile mouse cardiomyocytes. After transplantation into the infarcted mouse hearts, IGF-II-PSC-derived cardiomyocytes displayed significant characteristics of mature cardiomyocytes, and IGF-II-depletion by shRNA significantly reversed these effects, suggesting the critical role of IGF-II in promoting cardiomyocyte maturation in vivo. Furthermore, IGF-II-overexpressing PSC derivatives reduced collagen deposition and mitochondrial damage in the infarcted areas and improved cardiac function. The re-knockdown of IGF-II could counteract these favorable effects of IGF-II.ConclusionsThese findings suggest that the ectopic expression of IGF-II accelerates PSC differentiation into the cardiac lineage and promotes cardiomyocyte maturation. The underlying process includes the IGF-II/IGF1R signaling, which is involved in the suppressive effect of IGF-II on PSC proliferation. Moreover, transplanting IGF-II-overexpressing PSC derivatives into the infarcted heart could reduce collagen deposition and improve mitochondria biogenesis and measurements of cardiac function, highlighting the importance of IGF-II in the application of PSCs in cardiac regeneration.

A preliminary study on abnormal expression of long noncoding RNA CTD- 2012K14.6 in placentas and its role in inducing macrosomia

Objective To explore the role of long noncoding RNA (lncRNA) CTD-2012K14.6 in the development of gestational diabetes mellitus (GDM) related macrosomia. Methods The quantitative real-time PCR (qRT-PCR) was performed to measure the expression of CTD-2012K14.6 in placentas of women with or without GDM, and the quantity of CTD-2012K14.6 expression and its association with fetal weights were analyzed; Bioinformatic analysis was performed to predict the downstream molecules. CTD-2012K14.6 over-expressing lentiviral and siRNA was constructed in human trophoblastic cell line HTR-8/SVneo cells, qRT-PCR and Western blot (WB) were used to invest its effect in modulating the expression of downstream molecules. Results The expression of CTD-2012K14.6 in GDM placentas was significantly higher than that in normal controls (1.70±0.63 vs 1.00±0.56, t=3.68, P<0.01), and positively correlated with fetal weight (r=0.8501, P<0.01); on-line analysis showed that CTD-2012K14.6 was located at chr16: 67, 549, 214-67, 563, 958, which was located in the intron of CCCTC-binding factor(CTCF); Up-regulating CTD-2012K14.6 could significantly reduce the expression of CTCF mRNA and protein, and increase the expression of insulin-like growth factor-Ⅱ(IGF-Ⅱ) mRNA and protein, while down-regulating CTD-2012K14.6 could significantly increase the expression of CTCF mRNA and protein, and reduce the expression of IGF-Ⅱ mRNA and protein. Conclusion The CTD-2012K14.6 may play an important role in the pathogenesis of GDM related macrosomia by upregulating the expression of CTCF and IGF-Ⅱ. Key words: Gestational diabetes mellitus; Macrosomia; Long noncoding RNA CTD-2012K14.6; CCCTC-binding factor; Insulin-like growth factor 2

Alteration of oncogenic IGF-II gene methylation status associates with hepatocyte malignant transformation

BackgroundOncogenic insulin-like growth factor-II (IGF-II) is overexpressed in hepatocellular carcinoma (HCC). The present study aimed to analyze the dynamic alteration of IGF-II CpG site methylation status and its molecular mechanism in HCC progression. MethodsIGF-II alterations were observed in rat hepatocarcinogenesis models induced by 2-acetylaminofluorene. Liver IGF-II expression was compared by immunohistochemistry or tissue IGF-II specific concentration (nmol/mg protein). Status of human IGF-II promoter 3 (P3) or rat IGF-II P2 CpG site methylation was amplified by methylation-specific polymerase chain reaction (MSP). Serum IGF-II levels were quantitatively detected by an enzyme-linked immunosorbent assay. ResultsThe levels of hepatic IGF-II expression were significantly elevated in the HCC group (P < 0.001). The unmethylation rate of IGF-II P3 CpG sites was 100% in the HCC-, 52.5% in the paracancerous-, and none (0%) in the distal noncancerous-tissues. Abnormal IGF-II expression was related to differentiation degree, tumor invasion, and positive HBV-DNA (all P < 0.001), with a negative correlation between P3 methylation degree and IGF-II expression. There was a positive correlation between liver IGF-II specific concentration and circulating IGF-II level (r = 0.97, P < 0.001). Significantly negative correlation was found between IGF-II P2 CpG site methylation and circulating IGF-II (rs = −0.89, P < 0.001) or liver IGF-II level (rs = −0.84, P < 0.001). ConclusionsThe increase of serum IGF-II and the alteration of oncogenic gene IGF-II methylation may be biomarkers for HCC diagnosis and DNA methylation may be the therapeutic target of HCC.

A Loss of Epigenetic Control Can Promote Cell Death through Reversing the Balance of Pathways in a Signaling Network

Epigenetic control of regulatory networks is only partially understood. Expression of Insulin-like growth factor-II (IGF2) is controlled by genomic imprinting, mediated by silencing of the maternal allele. Loss of imprinting of IGF2 (LOI) is linked to intestinal and colorectal cancers, causally in murine models and epidemiologically in humans. However, the molecular underpinnings of the LOI phenotype are not clear. Surprisingly, in LOI cells, we find a reversal of the relative activities of two canonical signaling pathways triggered by IGF2, causing further rebalancing between pro- and anti-apoptotic signaling. A predictive mathematical model shows that this network rebalancing quantitatively accounts for the effect of receptor tyrosine kinase inhibition in both WT and LOI cells. This mechanism also quantitatively explains both the stable LOI phenotype and the therapeutic window for selective killing of LOI cells, and thus prevention of epigenetically controlled cancers. These findings suggest a framework for understanding epigenetically modified cell signaling.

Silencing IGF-II impairs C-myc and N-ras expressions of SMMC-7721 cells via suppressing FAK/PI3K/Akt signaling pathway

Emerging evidence confirms that insulin-like growth factor -II (IGF-II), oncogenes C-myc and N-ras are an essential regulator for development and growth in hepatocellular carcinoma (HCC). Although our previous study also indicated that IGF-II might upregulate levels of oncogenes C-myc and N-ras in hepatoma carcinoma cells, the molecular mechanism had not been fully elucidated. Herein, we successfully silenced IGF-II expression in SMCC-7721 cells by small RNA interference. Functional analysis showed that knockdown of IGF-II significantly suppressed growth and proliferation of SMMC-7721 cells and decreased C-myc and N-ras mRNA and protein levels. And this function was mediated by the FAK/PI3K/Akt signaling pathway. Taken together, IGF-II siRNA inactivates the FAK/PI3K/Akt signaling pathway, and further reduces cell proliferation, N-ras and C-myc levels in SMMC-7721 cells. Especially, understanding the relationship between IGF-II and oncogenes N-ras and C-myc in cancer cells will provide novel clues for clinic HCC treatment in the future.

Insulin-Like Growth Factor II (IGF-II) Inhibits IL-1β-Induced Cartilage Matrix Loss and Promotes Cartilage Integrity in Experimental Osteoarthritis.

Osteoarthritis (OA) is a widespread chronic joint disease characterized by articular cartilage destruction and accompanied by pain and disability. In this study, we found that the expression of Insulin-like Growth Factor II (IGF-II) was reduced in articular cartilage in human OA patients as well as in the murine experimental OA model of destabilization of the medial meniscus (DMM). In primary human articular chondrocytes, ectopic expression of lentiviral IGF-II inhibited pro-inflammatory cytokine IL-1β-induced NF-κB activation as well as catabolic gene expression. Interestingly, IGF-II did not significantly alter the phosphorylation states of ERK1/2 or Akt, which are kinases typically activated by IGF-I. Instead, it induced the activity of phospholipase C (PLC) and a PLC inhibitor blocked the inhibitory activity of IGF-II against IL-1β, suggesting that this activity is mediated through PLC. Furthermore, IGF-II increased cartilage matrix levels and decreased MMP13 protein expression in explanted human OA cartilage cultures in vitro. In the in vivo DMM model, intraarticular injection of lentiviral IGF-II led to enhanced cartilage matrix levels and decreased MMP13 protein expression, as well as reduced osteophyte formation and subchondral bone sclerosis. Therefore, our results suggest that IGF-II can promote cartilage integrity and halt knee joint destruction in OA.

Prenatal cocaine exposure impairs cognitive function of progeny via insulin growth factor II epigenetic regulation

Studies have showed that prenatal cocaine exposure (PCOC) can impair cognitive function and social behavior of the offspring; however, the mechanism underlying such effect is poorly understood. Insulin-like growth factor II (Igf-II), an imprinted gene, has a critical role in memory consolidation and enhancement. We hypothesized that epigenetic regulation of hippocampal Igf-II may attribute to the cognitive deficits of PCOC offspring. We used Morris water maze and open-field task to test the cognitive function in PCOC offspring. The epigenetic alteration involved in hippocampal Igf-II expression deficit in PCOC offspring was studied by determining Igf-II methylation status, DNA methyltransferases (DNMT) expressions and l-methionine level. Moreover, IGF-II rescue experiments were performed and the downstream signalings were investigated in PCOC offspring. In behavioral tests, we observed impaired spatial learning and memory and increased anxiety in PCOC offspring; moreover, hippocampal IGF-II mRNA and protein expressions were significantly decreased. Hippocampal methylation of cytosine-phospho-guanine (CpG) dinucleotides in differentially methylated region (DMR) 2 of Igf-II was elevated in PCOC offspring, which may be driven by the upregulation of l-methionine and DNA methyltransferase (DNMT) 1. Importantly, intra-hippocampal injection of recombinant IGF-II reactivated the repressed calcium calmodulin kinase II α (CaMKIIα) and reversed cognitive deficits in PCOC offspring. Collectively, our findings suggest that cocaine exposure during pregnancy impairs cognitive function of offspring through epigenetic modification of Igf-II gene. Enhancing IGF-II signaling may represent a novel therapeutical strategy for cocaine-induced cognitive impairment.

Evaluation of antiglypican-3 therapy as a promising target for amelioration of hepatic tissue damage in hepatocellular carcinoma

In Egypt, hepatocellular carcinoma (HCC) was predicted to continue to rise over the next few decades causing a national problem. Meanwhile, glypican-3 (GPC3), a highly expressed glypican, has emerged as a potential target for HCC immunotherapy. Therefore, we aimed to identify the impact of blocking GPC3 on liver damage in HCC as well as a possible mechanism. Fifty four HCC patients, 20 cirrhotic patients and 10 healthy subjects were recruited. Serum levels of GPC3, sulfatase-2 (SULF-2), heparan sulfate proteoglycan (HSPG), insulin-like growth factor-II (IGF-II) were measured by ELISA. In parallel, HCC was induced in 40 male Sprague-Dawley rats in presence/absence of antiGPC-3. Liver impairment was detected by investigating liver sections stained with hematoxylin/eosin and serum α-fetoprotein (AFP). Liver homogenates of GPC3, SULF-2, and HSPG were measured by ELISA. Gene expression of caspase-3 and IGF-II were assayed by RT-PCR. HCC patients showed significant elevated serum levels of GPC3, IGF-II and SULF-2 accompanied by decreased HSPG. However, treatment of HCC rats with antiGPC-3 significantly reduced serum AFP and showed nearly normal hepatocytes. In addition, antiGPC-3 significantly reduced elevated liver homogenates protein levels of GPC3 and SULF-2 and gene expression of IGF-II and caspase-3. antiGPC-3 restored the reduced hepatic HSPG. antiGPC-3 showed anti-tumor activity as well as hepatoprotective effects. antiGPC-3-chemoprotective effect can be explained by forced reduction of IGF-II expression, restoration of HSPGs, deactivation of SULF-2 and reduction of gene expression of caspase-3. Targeting GPC3 is a promising therapeutic approach for HCC.

Effect of iron deficiency on the expression of insulin-like growth factor-II and its receptor in neuronal and glial cells

IntroductionMany studies have demonstrated that iron deficiency modifies the normal function of the central nervous system (CNS) and alters cognitive abilities. When cellular damage occurs in the CNS, neuroprotective mechanisms, such as the production of neurotrophic factors, are essential in order for nervous tissue to function correctly. Insulin-like growth factor II (IGF-II) is a neurotrophic factor that was recently shown to be involved in the normal functioning of cognitive processes in animal models. However, the impact of iron deficiency on the expression and function of this molecule has not yet been clarified. MethodsMixed primary cell cultures from the CNS were collected to simulate iron deficiency using deferoxamine. The expression of IGF-I, IGF-II, IGF-IR, and IGF-IIR was determined with the Western blot test. ResultsWe observed increased expression of IGF-II, along with a corresponding decrease in the expression of IGF-IIR, in iron-deficient (DFe) mixed primary cell cultures. We did not observe alterations in the expression of these proteins in isolated microglia or neuronal cultures under the same conditions. We did not detect differences in the expression of IGF-I and IGF-IR in DFe cultures. ConclusionsIn vitro iron deficiency increases the expression of IGF-II in mixed glial cell cultures, which may have a beneficial effect on brain tissue homeostasis in a situation in which iron availability is decreased.

Knockdown of IGF2R suppresses proliferation and induces apoptosis in hemangioma cells in vitro and in vivo.

Insulin-like growth factor-II (IGF-II)/IGF2R signaling plays a pivotal role in cell growth, migration and differentiation in many malignancies. An individual with high IGF-II expression levels has a high risk of developing cancer, but IGF2R is often considered to be a tumor suppressor. To date, little has been reported about the role of IGF-II/IGF2R signaling in hemangiomas (HAs). Thus, uncovering the mechanisms of IGF-II/IGF2R signaling is very important to understanding the development of HAs. In the present study, the expression of IGF-II and IGF2R was investigated in 27 cases of HAs of different phases by immunohistochemistry. Through lentivirus-mediated IGF2R siRNA (Lv-siIGF2R) in HA-derived endothelial cells (HDECs), we observed the effects of IGF2R knockdown on the biological behavior of HA cells. We found that the expression of IGF-II and IGF2R was significantly increased in proliferating phase HAs, but decreased in involuting phase HAs. Furthermore, knockdown of IGF2R in vitro significantly diminished the proliferative activity and induced apoptosis and cycle arrest with decreased expression of PCNA, Ki-67, Bcl-2, Cyclin D1 and E and increased the expression of Bax in the proliferative phase HAs (HDEC and CRL-2586 EOMA cells). In addition, the tumor volumes in a subcutaneous HDEC nude mouse model treated with Lv-siIGF2R were significantly smaller than those of the control group. Taken together, our findings indicate that the expression of IGF-II and IGF2R is increased in proliferating phase HAs, and knockdown of IGF2R suppresses proliferation and induces apoptosis in HA cells in vitro and in vivo, suggesting that IGF2R may represent a novel therapeutic target for the treatment of human HAs.

Insulin‐like growth factor‐II: its role in metabolic and endocrine disease

Insulin-like growth factor-II (IGF-II) is a widely expressed 7·5 kDa mitogenic peptide hormone. Although it is abundant in serum, understanding of its physiological role is limited compared with that of IGF-I. IGF-II regulates foetal development and differentiation, but its role in adults is less well understood. Evidence suggests roles in a number of tissues including skeletal muscle, adipose tissue, bone and ovary. Altered IGF-II expression has been observed in metabolic conditions, notably obesity, diabetes and the polycystic ovary syndrome. This article summarizes what is known about the actions of IGF-II and its dysregulation in metabolic and endocrine diseases. The possible causes and consequences of dysregulation are discussed along with the implications for diagnostic tests and future research.

Effects of different dietary intake on mRNA levels of MSTN, IGF-I, and IGF-II in the skeletal muscle of Dorper and Hu sheep hybrid F1 rams.

MSTN, IGF-І(insulin-like growth factor-І) and IGF-II (insulin-like growth factor-II) regulate skeletal muscle growth. This study investigated the effects of different dietary intake levels on skeletal muscles. Sheep was randomly assigned to 3 feeding groups: 1) the maintenance diet (M), 2) 1.4 x the maintenance diet (1.4M), and 3) 2.15 x the maintenance diet (2.15M). Before slaughtering the animals, blood samples were collected to measure plasma urea, growth hormone, and insulin concentrations. After slaughtering, the longissimus dorsi, semitendinosus, semimembranosus, gastrocnemius, soleus, and chest muscle were removed to record various parameters, including the mRNA expression levels of MSTN and IGFs, in addition to skeletal muscle fiber diameter and cross-sectional area. The result showed that as dietary intake improved, the mRNA expression levels of MSTN and IGF-II decreased, whereas IGF-Іexpression increased. The mRNA expression levels of MSTN and IGFs were significantly different in the same skeletal muscle under different dietary intake. The skeletal muscle fiber diameter and cross-sectional area increased with greater dietary intake, as observed for the mRNA expression of IGF-І; however, it contrasted to that observed for the mRNA expression of MSTN and IGF-II. In conclusion, dietary intake levels have a certain influence on MSTN and IGFs mRNA expression levels, in addition to skeletal muscle fiber diameter and cross-sectional area. This study contributes valuable information for enhancing the molecular-based breeding of sheep.

Anti-insulin-like growth factor-IIP3 DNAzymes inhibit cell proliferation and induce caspase-dependent apoptosis in human hepatocarcinoma cell lines

BackgroundInsulin-like growth factor II (IGF-II) is a fetal growth protein and an important proangiogenic factor controlled by four promoters (P), of which P2–P4 are inactive in the adult liver. Reactivation and dysregulation of IGF-IIP3 in particular is associated with the attenuation of apoptosis and increased proliferation in a number of liver cancer cell types. Its involvement in experimental liver carcinogenesis makes it a potential target for cancer gene therapy. We designed two IGF-IIP3 specific DNAzymes (DRz1 and DRz2) that target IGF-IIP3 messenger RNA (mRNA) with the aim of reducing IGF-II expression through promoter 3.MethodsIGF-IIP3 mRNA and protein expression levels were assessed using real-time polymerase chain reaction and gel electrophoresis/western blotting after transfection with Lipofectamine® in SMMC-7721, Huh7, and HepG2 cell lines. Cell proliferation was determined via MTT assay; apoptosis was evaluated by fluorescence microscopy and with flow cytometry; procaspase-3 and -9 expression were detected via western blotting; and caspase activity was assayed colorimetrically. Standard procedures were used to calculate means and standard deviations, and P-values below 0.05 were considered to indicate significant differences.ResultsDRzs were transfected into hepatocellular carcinoma cells and the results showed that DRz1, in particular, could decrease the expression of IGF-IIP3 by nearly 50%. Furthermore, DRz1 significantly inhibited cell proliferation and induced apoptosis. In addition, the down-regulation of IGF-IIP3 expression was associated with increased caspase-3 and -9 activity in SMMC-7721 cells after 24 hours of transfection. In all experiments, the efficacy of DRz2 to influence IGF-IIP3 levels and associated effects remained second to DRz1.ConclusionOverall, these results suggest that DRz1-based targeting of IGF-IIP3 mRNA might have antitumorigenic activity and may potentially provide the basis for a novel therapeutic intervention in liver cancer treatment, although further development is required.

Non–Islet Cell Tumor-Induced Hypoglycemia Associated with Macronodular Pulmonary Metastases from Poorly Differentiated Thyroid Carcinoma

Non-islet cell tumor-induced hypoglycemia (NICTH), a major cause of fasting hypoglycemia, is caused by the overproduction of incompletely processed, high molecular-weight insulin-like growth factor-II (IGF-II), termed "big" IGF-II. To the best of our knowledge, only two cases of thyroid carcinoma associated with NICTH have been documented. We report the case of a 72-year-old woman who was brought to the emergency department with impaired consciousness. The patient had a history of pulmonary metastases from poorly differentiated thyroid carcinoma (PDTC), spanning 12 years since initial treatment. Laboratory tests showed decreased plasma glucose levels even though immunoreactive insulin, IGF-I, and growth hormone (GH) were undetectable. Computed tomography (CT) scan revealed macronodular pulmonary metastases the estimated volume of which was 456 mL. Both the biochemical data and imaging results suggested NICTH. The results of Western blot analysis performed on a fractionated serum sample showed an increased expression of big IGF-II, an important indicator in the diagnosis of NICTH. Because the massive pulmonary metastases were considered inoperable, immunohistochemical analysis of stored formalin-fixed, paraffin-embedded tissues was performed. The analysis revealed that the tumor cells were positive for both IGF-II and thyroglobulin. A whole-body CT excluded extrapulmonary metastatic lesions. A retrospective review revealed a gradual decrease in glycohemoglobin levels accompanied by an increase in the estimated volume of pulmonary metastases. These findings suggested that NICTH had been caused by pulmonary metastases from PDTC. We describe here the third reported case of NICTH associated with thyroid carcinoma. This is also the first case reporting big IGF-II in the serum of a patient with thyroid carcinoma.

An insulin-like growth factor-II intronic variant affects local DNA conformation and ovarian cancer survival

Insulin-like growth factor-II (IGF-II) may be a prognostic marker in ovarian cancer, and its intronic single nucleotide polymorphism (SNP) rs4320932 has been associated with risk of the disease. We determined whether rs4320932 is associated with IGF-II expression and patient survival in ovarian cancer, and explored whether the SNP variation affects DNA conformation both in the absence of and presence of carboplatin. IGF-II genotype (rs4320932) and phenotype were analyzed in 212 primary invasive epithelial ovarian cancer tissue samples with Taqman® SNP genotyping assays, quantitative reverse transcription-polymerase chain reaction and commercial enzyme-linked immunosorbent assay. DNA conformation was evaluated by circular dichroism (CD) spectra. Kaplan-Meier survival curves and Cox proportional hazard regression models were used to analyze the SNP associations with patient survival. The C allele of rs4320932, previously associated with decreased risk of ovarian cancer development, was here associated with significantly elevated risks of relapse (Ptrend = 0.0002) and death (Ptrend = 0.0006), remaining significant in multivariate analyses. The adjusted hazard ratios were 3.05 (95% confidence interval [CI]: 1.47-6.37) for relapse and 3.28 (95% CI: 1.64-6.57) for death, respectively. The variant was also significantly associated with chemotherapy response, but not with other clinicopathologic variables or with IGF-II expression. DNA with genotypes TT and CC had distinct CD spectra in both the absence of and presence of carboplatin. These findings suggest that the intronic SNP rs4320932 affects patient survival and chemotherapy response via alteration of DNA conformation, but not through regulation of IGF-II expression. This novel finding may have implications in individualized medicine for the design of specific molecules targeting DNA of specific conformations.

Abstract 536: Insulin-like growth factor II (IGF-II) is a potential target for the treatment of triple negative breast cancers (TNBC).

Abstract In the United States, African American (AA) women have a lower incidence of breast cancer compared to Caucasian (CA) women, but higher overall mortality. Our lab have demonstrated that Breast Cancer from AA patients express significantly higher levels of IGF-II and show a higher activation of the IGF signaling system in African American (AA) when compared to Caucasian (CA) women. We showed that IGF-II promotes breast cancer progression and metastasis by inhibiting tumor cell death and promoting resistance to chemotherapy, thus contributing to increased breast cancer (BC) mortality. This study was designed to determine how IGF-II contributes to the aggressiveness of TNBC, the most deadly of breast tumors, which is highly prevalent among AA. To analyze IGF-II in a TNBC cell model, we chose cell lines established from tumors of AA and CA breast cancer patients. Expression of IGF-II and IGF-II regulated proteins mRNA expression was probed using the CFX96 real time PCR system. Similarly, IGF-II and related proteins expression was analyzed by western blots and chemiluminescence. We also characterized the epigenetic activation of IGF-II in these cell lines since variation in the expression of IGF-II alleles regulates a signature of proteins associated with tumor aggressiveness. Our exciting results demonstrated that higher IGF-II levels in TNBC cells from AA was associated with distinct epigenetic changes that included different promoter activation and higher levels of IGF-II translation which are inheritable traits. In contrast, TNBC from CA had higher IGF-II levels due to different molecular IGF-II regulation. Thus, IGF-II is an important biomarker and can be used as therapeutic target for treatment of TNBC. Citation Format: Vinodh Kumar Radhakrishnan, Qianwei Tan, Marino A. De León, Daisy D. De León. Insulin-like growth factor II (IGF-II) is a potential target for the treatment of triple negative breast cancers (TNBC). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 536. doi:10.1158/1538-7445.AM2013-536