Upregulation Of Insulin-like Growth Factor Research Articles

Pharmacological interventions for improved colonic anastomotic healing: a meta-analysis.

To identify pharmaceuticals for the prophylaxis of anastomotic leakage (AL), we systematically reviewed studies on anastomosis repair after colorectal surgery. We searched PubMed and EMBASE for articles published between January 1975 and December 2012. We included studies in English with the primary purpose of promoting healing of anastomoses made in the colon or rectum under uncomplicated conditions. We excluded studies on adverse events from interventions, nutritional interventions or in situ physical supporting biomaterials. The primary outcome was biomechanical strength or AL. We performed meta-analyses on therapeutic agents investigated by three or more independent research groups using the same outcome. The DerSimonian-Laird method for random effects was applied with P < 0.05. Of the 56 different therapeutic agents assessed, 7 met our inclusion criteria for the meta-analysis. The prostacyclin analog iloprost increased the weighted mean of the early bursting pressure of colonic anastomoses in male rats by 60 mmHg (95%CI: 30-89) vs the controls, and the immunosuppressant tacrolimus increased this value by 29 mmHg (95%CI: 4-53) vs the controls. Erythropoietin showed an enhancement of bursting pressure by 45 mmHg (95%CI: 14-76). The anabolic compound growth hormone augmented the anastomotic strength by 21 mmHg (95%CI: 7-35), possibly via the up-regulation of insulin-like growth factor-1, as this growth factor increased the bursting pressure by 61 mmHg (95%CI: 43-79) via increased collagen deposition. Hyperbaric oxygen therapy increased the bursting pressure by 24 mmHg (95%CI: 13-34). Broad-spectrum matrix metalloproteinase inhibitors increased the bursting pressure by 48 mmHg (95%CI: 31-66) on postoperative days 3-4. In the only human study, the AL incidence was not significantly reduced in the 103 colorectal patients treated with aprotinin (11.7%) compared with the 113 placebo-treated patients (9.7%). This systematic review identified only one randomized clinical trial and seven therapeutic agents from pre-clinical models that could be explored further for the prophylaxis of AL after colorectal surgery.

Reversion of erlotinib-acquired resistance twice by chemotherapy

Epidermal growth factor receptor (EGFR) mutations in patients with non-small cell lung cancer (NSCLC) usually develop disease progression after a median of 10 to 14 mo on tyrosine kinase inhibitor (TKI). Several mechanisms of resistance to TKI have been described, threonine-methionine substitution at position 790 (T790M), mesenchymal–epithelial transition factor (MET) amplification, overexpression of hepatocyte growth factor (HGF), upregulation of insulin-like growth factor (IGF) receptor signaling, transformation to small cell lung cancer, and so on. A variety of different therapeutic approaches aimed at overcoming resistance are motivated, irreversible EGFR inhibitors, combination with EGFR targeted antibodies, mesenchymal–epithelial transition factor (MET) inhibitors, HGF inhibitors, and so forth. Nevertheless, the results were not optimistic. Here we report a case of reversion of erlotinib-acquired resistance twice, and had a good improvement of outcomes every time. There are some possible reasons for this phenomenon. Considering this report, the patients who acquired resistance after retreatment of EGFR-TKI, using EGFR-TKI repeatedly may be a choice selectively.

Expression and clinical significance of IGF-1, IGFBP-3, and IGFBP-7 in serum and lung cancer tissues from patients with non-small cell lung cancer

The expression and clinical significance of insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP-3), and insulin-like growth factor binding protein 7 (IGFBP-7) were investigated in serum and lung cancer tissues from 57 patients with non-small cell lung cancer (NSCLC). Lung cancer tissues at different pathologic stages (27 patients at stages I–II and 30 patients at stages III–IV), normal lung tissues from 17 patients with benign pulmonary disease, and serum samples from both lung cancer and benign pulmonary disease patients were collected during surgery. Enzyme-linked immunosorbent assay and avidin-biotin-peroxidase complex immunohistochemical staining were used to detect IGF-1, IGFBP-3, and IGFBP-7 expression in serum and tissues, respectively. The results show that expression of IGF-1 in lung cancer tissues and serum from NSCLC patients were significantly higher than in the control (P < 0.05). However, expression of IGFBP-3 and IGFBP-7 in cancer tissues and serum from NSCLC patients was significantly lower than in the control (P < 0.05). These results suggest that upregulation of IGF-1 and downregulation of IGFBP-3 and IGFBP-7 may be potential diagnostic biomarkers for NSCLC.

Enhanced delivery of human growth hormone across cell membrane by Tat-PTD

In this study, we utilized the HIV protein Tat protein transduction domain (Tat-PTD) to enhance the intestinal absorption of recombinant human growth hormone (rhGH) delivered by oral administration. Insulin-like growth factor 1 (IGF-1), the key factor in the GH signal transduction pathway, was differentially affected at the mRNA level by various concentrations of rhGH. At high rhGH concentrations (500 ng/ml), IGF-1 was downregulated, while low concentrations (5 ng/ml) caused IGF-1 upregulation. The addition of Tat-PTD had a significant facilitating effect on rhGH. Frozen tissue sections visualized with fluorescence microscopy, cultured cells visualized by confocal microscopy and flow cytometry all confirmed that rhGH fused to Tat-PTD demonstrated more intracellular fluorescent signal when compared to rhGH alone. ELISA showed that after 2 h of incubation, Tat-rhGH levels in the rat intestinal cavity were 1.38-fold higher than rhGH. These data indicated that Tat-PTD effectively improved the internalization of rhGH and enhance the signal transduction of rhGH, possibly laying a solid foundation for the novel oral administration of rhGH.

Upregulation of insulin‐like growth factor and interleukin 1β occurs in neurons but not in glial cells in the cochlear nucleus following cochlear ablation

One of the main mechanisms used by neurons and glial cells to promote repair following brain injury is to upregulate activity-dependent molecules such as insulin-like growth factor 1 (IGF-1) and interleukin-1β (IL-1β). In the auditory system, IGF-1 is crucial for restoring synaptic transmission following hearing loss; however, whether IL-1β is also involved in this process is unknown. In this study, we evaluated the expression of IGF-1 and IL-1β within neurons and glial cells of the ventral cochlear nucleus in adult rats at 1, 7, 15, and 30 days following bilateral cochlear ablation. After the lesion, significant increases in both the overall mean gray levels of IGF-1 immunostaining and the mean gray levels within cells of the cochlear nucleus were observed at 1, 7, and 15 days compared with control animals. The expression and distribution of IL-1β in the ventral cochlear nucleus of ablated animals was temporally and spatially correlated with IGF-1. We also observed a lack of colocalization between IGF-1 and IL-1β with either astrocytes or microglia at any of the time points following ablation. These results suggest that the upregulation of IGF-1 and IL-1β levels within neurons-but not within glial cells-may reflect a plastic mechanism involved in repairing synaptic homeostasis of the overall cellular environment of the cochlear nucleus following bilateral cochlear ablation.

GW24-e2363 PHD2 Silencing enhances the survival and paracrine function of transplanted adipose-derived stem cells in infarcted myocardium

ObjectivesWe studied if and how PHD2 silencing in human adipose-derived stem cells (ADSCs) enhances their cardioprotective effects after transplantation into infarcted hearts.MethodsADSCs were transduced with lentiviral shPHD2 to silence PHD2....

Autocrine IGF-I/insulin receptor axis compensates for inhibition of AKT in ER-positive breast cancer cells with resistance to estrogen deprivation

IntroductionEstrogen receptor α-positive (ER+) breast cancers adapt to hormone deprivation and acquire resistance to antiestrogen therapies. Upon acquisition of hormone independence, ER+ breast cancer cells increase their dependence on the phosphatidylinositol-3 kinase (PI3K)/AKT pathway. We examined the effects of AKT inhibition and its compensatory upregulation of insulin-like growth factor (IGF)-I/InsR signaling in ER+ breast cancer cells with acquired resistance to estrogen deprivation.MethodsInhibition of AKT using the catalytic inhibitor AZD5363 was examined in four ER+ breast cancer cell lines resistant to long-term estrogen deprivation (LTED) by western blotting and proliferation assays. Feedback upregulation and activation of receptor tyrosine kinases (RTKs) was examined by western blotting, real-time qPCR, ELISAs, membrane localization of AKT PH-GFP by immunofluorescence and phospho-RTK arrays. For studies in vivo, athymic mice with MCF-7 xenografts were treated with AZD5363 and fulvestrant with either the ATP-competitive IGF-IR/InsR inhibitor AZD9362 or the fibroblast growth factor receptor (FGFR) inhibitor AZD4547.ResultsTreatment with AZD5363 reduced phosphorylation of the AKT/mTOR substrates PRAS40, GSK3α/β and S6K while inducing hyperphosphorylation of AKT at T308 and S473. Inhibition of AKT with AZD5363 suppressed growth of three of four ER+ LTED lines and prevented emergence of hormone-independent MCF-7, ZR75-1 and MDA-361 cells. AZD5363 suppressed growth of MCF-7 xenografts in ovariectomized mice and a patient-derived luminal B xenograft unresponsive to tamoxifen or fulvestrant. Combined treatment with AZD5363 and fulvestrant suppressed MCF-7 xenograft growth better than either drug alone. Inhibition of AKT with AZD5363 resulted in upregulation and activation of RTKs, including IGF-IR and InsR, upregulation of FoxO3a and ERα mRNAs as well as FoxO- and ER-dependent transcription of IGF-I and IGF-II ligands. Inhibition of IGF-IR/InsR or PI3K abrogated AKT PH-GFP membrane localization and T308 P-AKT following treatment with AZD5363. Treatment with IGFBP-3 blocked AZD5363-induced P-IGF-IR/InsR and T308 P-AKT, suggesting that receptor phosphorylation was dependent on increased autocrine ligands. Finally, treatment with the dual IGF-IR/InsR inhibitor AZD9362 enhanced the anti-tumor effect of AZD5363 in MCF-7/LTED cells and MCF-7 xenografts in ovariectomized mice devoid of estrogen supplementation.ConclusionsThese data suggest combinations of AKT and IGF-IR/InsR inhibitors would be an effective treatment strategy against hormone-independent ER+ breast cancer.

Prolyl Hydroxylase Domain Protein 2 Silencing Enhances the Survival and Paracrine Function of Transplanted Adipose-Derived Stem Cells in Infarcted Myocardium

Transplantation of stem cells into damaged hearts has had modest success as a treatment for ischemic heart disease. One of the limitations is the poor stem cell survival in the diseased microenvironment. Prolyl hydroxylase domain protein 2 (PHD2) is a cellular oxygen sensor that regulates 2 key transcription factors involved in cell survival and inflammation: hypoxia-inducible factor and nuclear factor-κB. We studied whether and how PHD2 silencing in human adipose-derived stem cells (ADSCs) enhances their cardioprotective effects after transplantation into infarcted hearts. ADSCs were transduced with lentiviral short hairpin RNA against prolyl hydroxylase domain protein 2 (shPHD2) to silence PHD2. ADSCs, with or without shPHD2, were transplanted after myocardial infarction in mice. ADSCs reduced cardiomyocyte apoptosis, fibrosis, and infarct size and improved cardiac function. shPHD2-ADSCs exerted significantly more protection. PHD2 silencing induced greater ADSC survival, which was abolished by short hairpin RNA against hypoxia-inducible factor-1α. Conditioned medium from shPHD2-ADSCs decreased cardiomyocyte apoptosis. Insulin-like growth factor-1 (IGF-1) levels were significantly higher in the conditioned medium of shPHD2-ADSCs versus ADSCs, and depletion of IGF-1 attenuated the cardioprotective effects of shPHD2-ADSC-conditioned medium. Nuclear factor-κB activation was induced by shPHD2 to induce IGF-1 secretion via binding to IGF-1 gene promoter. PHD2 silencing promotes ADSCs survival in infarcted hearts and enhances their paracrine function to protect cardiomyocytes. The prosurvival effect of shPHD2 on ADSCs is hypoxia-inducible factor-1α dependent, and the enhanced paracrine function of shPHD2-ADSCs is associated with nuclear factor-κB-mediated IGF-1 upregulation. PHD2 silencing in stem cells may be a novel strategy for enhancing the effectiveness of stem cell therapy after myocardial infarction.

Expression of insulin-like growth factor 1 receptor in rat retina following optic nerve injury

To investigate the apoptosis in retinal ganglion cells (RGCs) and insulin-like growth factor 1 receptor (IGF-1R) in the retina following optic nerve crush. Healthy Wistar rats (N = 70) were divided into two groups: a normal control group and an optic nerve injury group. Immunohistochemistry and flow cytometry were performed to detect the expression of IGF-1R and to measure the apoptosis of RGCs, respectively. Immunohistochemistry revealed that at 1 hr after optic nerve injury, IGF-1R immunoreactivity began to increase and reached a maximal level at 24 hr (p < 0.05), where it remained elevated up to 14 days after injury. RGC apoptosis in the normal control group was 0.53%, while the apoptosis rate in the optic nerve injury group increased over time. The apoptosis rate in the optic nerve injury group was 1.4% at 1 hr, 4.4% at 6 hr, 5.2% at 12 hr and reached a maximal level (8.5%) at 24 hr. Subsequently, the rate declined to 1.9% 7 days after injury and 0.9% 2 weeks after injury. The IGF-1R immunereactivity in the retina increased after optic nerve injury. IGF-1R may regulate the apoptosis and regeneration of RGCs at different stages after optic nerve injury.

Deficiency in androgens and upregulation of insulin-like growth factor-1 are involved in high bone turnover in men receiving androgen deprivation therapy for prostate cancer

ObjectiveThis study was performed to elucidate the mechanism of high bone turnover during androgen deprivation therapy (ADT) in terms of osteogenic endocrine activity by testosterone, adrenal androgens, and insulin-like growth factor-1 (IGF-I), and to identify markers reflecting the bone mineral density (BMD) during ADT. DesignBMD and samples of blood and urine were studied before and after 6months of ADT in 70 patients with localized prostate cancer. ResultsBefore ADT, serum free-testosterone, dehydroepiandrosterone sulfate (DHEA-S), androstenedione, and IGF-I levels were correlated with BMD (rs=0.344, p=0.004; rs=0.264, p=0.027; rs=0.329, p=0.005; rs=0.300, p=0.012, respectively). The serum IGF-I level was independently correlated with the pretreatment BMD (Multivariate p=0.001). These relationships disappeared after ADT (p=0.519, 0.316, 0.116, and 0.597, respectively). After ADT, serum levels of free-testosterone decreased (7.9 to 0.2pg/mL), and DHEA-S and androstenedione were also reduced (3.6 to 2.3μmol/L and 5.6 to 2.9nmol/L, respectively) (p<0.001 in all). In contrast, IGF-I levels were elevated after ADT by 11.6% (19.9 to 22.3nmol/L, p<0.001). Delta-values of IGF-I (post- minus pretreatment levels, mean: +2.2, ranged between −7.1 and +15.3) were inversely correlated with the pretreatment (rs=−0.333 p=0.005) and post-treatment (rs=−0.408, p=0.001) BMD. After ADT, the serum IGF-I level was closely correlated with the serum level of the bone formation marker bone-specific alkaline phosphatase (BAP) (rs=0.328, p=0.006), and delta-IGF-I and delta-BAP showed a close positive correlation (rs=0.388, p=0.001). The post-treatment BMD was correlated only with the urine deoxypyridinoline (DPD) concentration (rs=−0.302, p=0.024) among the bone formation/resorption markers including serum/urine N-telopeptide. ConclusionsSerum IGF-I levels increased during ADT in men with a low BMD. Coupled with reduced androgen levels, elevated IGF-I levels, which were positively correlated with BAP during ADT, possibly explain the mechanism of ADT-related high bone turnover. The increase of IGF-I is more prominent in men whose BMD is already low at the baseline, and urine DPD might be a marker that reflects BMD during ADT.

Elevation of IGF‐2 receptor and the possible underlying implications in end‐stage heart failure patients before and after heart transplantation

Up-regulation of insulin-like growth factor 2 receptor (IGF-2R) involved in angiotensin II–induced cell apoptosis in cardiomyoblasts, and correlated with cardiomyocyte apoptosis in hypertensive rat hearts. Here, we detected IGF-2R levels and explored the possible underlying implications in end-stage heart failure (HF) patients before and after heart transplantation. Western blot and immunohistochemistry were used to measure cardiac IGF-2R levels. ELISA was used to detect serum IGF-2R and CD8 levels. Labelling of DNA strand breaks and dihydroethidium detection were used to determine cellular apoptosis and reactive oxygen species, respectively. Cardiac IGF-2R levels increased in end-stage HF patients (n = 11) compared with non-failing control subjects. Leu27-IGF-2, an IGF-2 analogue to activate specially the IGF-2R, could induce apoptosis and reactive oxygen species production in neonatal rat ventricular myocytes. The serum IGF-2R levels were significantly higher in HF patients than those in non-failing control subjects. An unexpected observation is that the serum IGF-2R levels further increased after heart transplantation, peaked at the first month, and gradually reduced close to the levels before heart transplantation at the 6th months after heart transplantation. Serum CD8, a marker of acute rejection, had no change after heart transplantation, but IGF-2R and Granzyme B, as a ligand for the IGF-2R and a marker for CD8 T lymphocyte activation, coexisted in the transplanted hearts. Our preliminary studies suggest that elevation of IGF-2R may participate in pathological process of end-stage HF and involved in the acute cellular rejection after heart transplantation.

The retinoic acid-induced up-regulation of insulin-like growth factor 1 and 2 is associated with prolidase-dependent collagen synthesis in UVA-irradiated human dermal equivalents

Ultraviolet (UV) A irradiation causes the degeneration of extracellular matrix in the skin dermis, mainly due to disrupted collagen homeostasis, resulting in the photo-aging of human skin. All-trans retinoic acid (ATRA) improves photo-aged human skin in vivo. Although the effects of ATRA on collagen synthesis and MMP regulation are well known, the effects of ATRA on other collagen homeostasis-associated genes have not been elucidated. This study was aimed to study the factors that are pharmacologically associated with the effect of ATRA on collagen homeostasis. The gene transcription profile of collagen homeostasis-associated genes was systematically evaluated in three-dimensional human dermal equivalents (HDEs) following UVA-irradiation and/or ATRA treatment. In addition to the expected changes in MMPs and collagen synthesis in HDEs in response to ATRA, prolidase, an important enzyme in the recycling of proline and hydroxyproline from degraded collagen molecules, was significantly decreased by UVA irradiation, and its down-regulation was antagonized by ATRA. Transfection with a prolidase-specific siRNA led to a significant decrease in procollagen synthesis in human fibroblasts. ATRA inhibited the UVA irradiation-induced decrease in prolidase activity through an insulin-like growth factor (IGF) receptor signaling pathway in HDEs. ARTA increased IGF1 and IGF2 production in HDEs, and neutralizing IGFs with anti-IGF antibodies abolished the effect of ATRA on proliase activity. These data demonstrate that ATRA regulates prolidase activity in HDEs via IGF receptor signaling, suggesting one of the pharmacological mechanisms by which improves photo-aged human skin.

Mesenchymal stem cells attenuate angiotensin II-induced aortic aneurysm growth in apolipoprotein E-deficient mice

Aortic aneurysm (AA) is associated with loss of elastin and structural integrity, accompanied by increased matrix metalloproteinase (MMP) expression. These processes are supported by inflammatory macrophages, with mediators such as tumor necrosis factor-α (TNF-α). Mesenchymal stem cells (MSCs) contribute to aortic remodeling. Therefore, to clarify whether MSCs might be useful for AA cell therapy, we examined the effect of MSCs on vascular smooth muscle cells (SMCs) and macrophages in vitro, on aortic tissue ex vivo, and on aorta in vivo. Murine macrophages and SMCs were cultured, with or without bone marrow-derived murine MSCs, for 96 hours in vitro. Gene expression of MMPs and TNF-α from macrophages and that of elastin from SMCs were measured. The murine aortic tissues were cultured with or without MSCs for up to 14 days, followed by measurement of MMP enzyme activity and elastin content. The in vivo aneurysm model used apolipoprotein E-deficient (apoE(-/-)) male mice receiving angiotensin II (Ang II) infusion for 28 days. MSCs were implanted by laparotomy to the abdominal aortic adventitial surface from the superior mesenteric artery origin to the left renal artery. Age-matched apoE(-/-) mice with or without Ang II infusion were used for control groups. At the end point, aortic diameter, elastin content, MMPs' activity, and cytokines expressed, including interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1), TNF-α, insulin-like growth factor-1 (IGF-1), and tissue inhibitor of metalloproteinases-1 (TIMP-1) were quantified. MSCs suppressed MMP-2 with or without MSCs (2.59 vs 3.94, P < .05), MMP-9 (5.83 vs 9.70, P < .05), and TNF-α (2.79 vs 3.38, P < .05) expression in macrophages, and promoted elastin expression in SMCs (19.35 vs 3.23, P < .05) in vitro. MSCs also decreased active MMP-2 activity (0.310 vs 0.0609 U/μL, P < .05) and preserved elastin content (68.05 vs 40.29 μg/mg, P < .05) ex vivo. AA development was site-specifically inhibited (0.73 vs 1.04 mm aortic diameter, P < .05) and elastin content was preserved (46.9 vs 25.6 μg/mg, P < .05) at 4 weeks. Downregulation of MMPs and IL-6, MCP-1, and TNF-α, and upregulation of IGF-1 and TIMP-1 were demonstrated with MSC implantation in vivo. MSC implantation inhibits Ang II-induced AA development in apoE(-/-) mice through elastin preservation in the aortic wall and is associated with attenuated levels of MMPs and inflammatory cytokines.

Acute skeletal muscle injury: CCL2 expression by both monocytes and injured muscle is required for repair

CC chemokine ligand 2 (CCL2), a ligand of CC chemokine receptor 2 (CCR2), is essential to mount an adequate inflammatory response to repair acute skeletal muscle injury. We studied the mechanisms by which CCL2 regulates muscle inflammation and regeneration. Mobilization of monocytes/macrophages (MOs/MPs) but not lymphocytes or neutrophils was impaired from bone marrow to blood and from blood to injured muscles in Ccl2(-/-) mice. This was accompanied by poor phagocytosis, reduced up-regulation of insulin-like growth factor-1 (IGF-1), and impaired muscle regeneration. Bone marrow transfer from wild-type mice to irradiated Ccr2(-/-) but not Ccl2(-/-) mice restored muscle inflammation. Intravenously injected CCL2-deficient bone marrow monocytes could not enter wild-type injured muscles as well as wild-type bone marrow monocytes. Intravenously injected wild-type bone marrow monocytes could not enter CCL2-deficient injured muscles as well as wild-type injured muscles. CCL2 stimulated IGF-1 expression by wild-type but not CCR2-deficient intramuscular macrophages. A single intramuscular injection of IGF-1, but not PBS, markedly improved muscle regeneration in Ccl2(-/-) mice. We conclude that CCL2 is a major ligand of CCR2 to recruit MOs/MPs into injured muscles to conduct phagocytosis and produce IGF-1 for injury repair. CCL2 needs to be expressed by bone marrow cells, circulating monocytes, and injured muscle tissue cells to recruit MOs/MPs into injured muscles. CCL2/CCR2 signaling also up-regulates IGF-1 expression by intramuscular macrophages to promote acute skeletal muscle injury repair.

Abstract 5031: Insulin-like growth factor-1 (IGF-1) is upregulated in low-grade serous ovarian carcinoma

Abstract Introduction: Low-grade (LG) serous ovarian carcinomas are clinically and genetically distinct from high-grade serous ovarian carcinomas (HG), and emerging evidence supports that LG form a molecular continuum with serous borderline ovarian tumors (SBOT). Despite an improved survival, LG ovarian cancer is relatively chemoresistant, and difficult to treat when it recurs. We sought to identify and validate the upregulation of IGF-1 in low-grade serous ovarian carcinomas. Methods: Gene expression profiling was performed with Affymetrix U133 to identify genes over-expressed in LG tumors compared to SBOT. Over-expression of IGF-1 in 18 LG tumors was validated by quantitative real-time polymerase chain reaction (qRT-PCR) and compared to IGF-1 expression in 9 serous borderline ovarian tumors (SBOT) and 15 HG tumors. Immunohistochemistry (IHC) of IGF-1 was performed on SBOT, LG, and HG samples and graded according to staining intensity. A low-grade cell line (HOC-7) was used to generate IGF-1 receptor (IGF-1R) knockdown stable cell lines with shRNA. Similarly, an IGF-1 plasmid was transfected into HOC-7 cells with resultant IGF-1 over-expression. Cells were then treated with IGF-1 at a concentration of 100 ng/mL for 15 and 60 minutes with controls. Phospho-Akt, total Akt, IGF-1R, and β-actin expression was confirmed by Western Blot analysis. Cell migration assays were performed with an HOC-7 control and shRNA IGF-1R knockdown cell lines. Finally, expression of IGF-1R was performed on LG paraffin sections and graded according to staining intensity on 43 patients. Clinical data including survival status, overall survival, stage, and debulking status was gathered and Kaplan-Meier curves were generated according to staining intensity. Results: In the Affymetrix analysis, several genes were significantly differentially expressed in LG tumors, one of which was IGF-1. Based on qRT-PCR results, expression of IGF-1 was significantly higher in LG tumors than SBOT (p&amp;lt;0.0005) and HG carcinomas (p=0.033). LG tumors also exhibited more robust IGF-1 IHC staining than SBOT or HG specimens. Phospho-Akt expression increased with increasing time of exposure to IGF-1 and in the IGF-1 over-expressing cell line compared to controls; whereas phospho-Akt expression was decreased in the IGF-1R knockdown cell lines. Decreased cellular migration was noted in the IGF-1R knockdown compared to the control. In the IHC analysis, 92% of the 43 LG slides stained positive for IGF-1R expression; however, correlation between staining intensity and patient survival was not significant. Conclusions: IGF-1 is overexpressed in low-grade serous epithelial ovarian tumors, and activates the phospho-Akt pathway through the IGF-IR. Particularly in LG ovarian tumors, which are less sensitive to chemotherapy and difficult to cure upon recurrence, further clinical investigation into the utility of IGF-targeted therapy is warranted. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5031. doi:10.1158/1538-7445.AM2011-5031

Manganese Induces IGF-1 and Cyclooxygenase-2 Gene Expressions in the Basal Hypothalamus during Prepubertal Female Development

Precocious puberty is a significant child health problem, especially in girls, because 95% of cases are idiopathic. Our earlier studies demonstrated that low-dose levels of manganese (Mn) caused precocious puberty via stimulating the secretion of luteinizing hormone-releasing hormone (LHRH). Because glial-neuronal communications are important for the activation of LHRH secretion at puberty, we investigated the effects of prepubertal Mn exposure on specific glial-derived puberty-related genes known to affect neuronal LHRH release. Animals were supplemented with MnCl(2) (10 mg/kg) or saline by gastric gavage from day 12 until day 22 or day 29, then decapitated, and brains removed. The site of LHRH release is the medial basal hypothalamus (MBH), and tissues from this area were analyzed by real-time PCR for transforming growth factor α (TGFα), insulin-like growth factor-1 (IGF-1), and cyclooxygenase-2 (COX-2) messenger RNA levels. Protein levels for IGF-1 receptor (IGF-1R) were measured by Western blot analysis. LHRH gene expression was measured in the preoptic area/anteroventral periventricular (POA/AVPV) region. In the MBH, at 22 days, IGF-1 gene expression was increased (p < 0.05) with a concomitant increase (p < 0.05) in IGF-1R protein expression. Mn also increased (p < 0.01) COX-2 gene expression. At 29 days, the upregulation of IGF-1 (p < 0.05) and COX-2 (p < 0.05) continued in the MBH. At this time, we observed increased (p < 0.05) LHRH gene expression in the POA/AVPV. Additionally, Mn stimulated prostaglandin E(2) and LHRH release from 29-day-old median eminences incubated in vitro. These results demonstrate that Mn, through the upregulation of IGF-1 and COX-2, may promote maturational events and glial-neuronal communications facilitating the increased neurosecretory activity, including that of LHRH, resulting in precocious pubertal development.

Localization and Function of Insulin-like Growth Factor 1 in Dorsal Root Ganglia in a Rat Disc Herniation Model

we investigated the localization of insulin-like growth factor 1 (IGF-1) using immunohistochemistry and the effects of small interfering RNA (siRNA) on IGF-1 in dorsal root ganglions (DRG) in a rat lumbar disc herniation (LDH) model. to determine the localization and function of IGF-1 in DRG of an experimental model of LDH. mechanical compression and chemical irritation are 2 major causative factors of radiculopathy in LDH. IGF-1, Ccnd1, Cdc2a, and CyclinA2 genes have been shown to be significantly upregulated in the mechanical model, but not in the chemical model. However, the localization and function of IGF-1 in DRG remain unknown in the mechanical compression animals. twenty-six adult female Sprague-Dawley rats were used in this study. A mechanical compression model was prepared by inserting a stainless rod. The rod was not inserted in the sham model. Expression of IGF-1 and Neuronal Nucli (NeuN) or glial fibrillary acidic protein was determined using double-fluorescence 7 days after mechanical compression (n = 5). Rats were randomly separated into 3 groups for the siRNA study (n = 7 in each group): (1) vehicle group; (2) siRNA group; and (3) sham group. The mechanical withdrawal threshold of the plantar food pad was examined using von Frey filaments for 35 days. IGF-1 was localized particularly in the neuronal cell body, and revealed that it colocalized with NeuN but not with glial fibrillary acidic protein. The threshold was reduced in the vehicle and siRNA groups compared with the sham group. The threshold of the siRNA group significantly recovered from reduction compared with the vehicle group at 5 days after surgery, and this effect persisted throughout the experimental period. CONCLUSION.: IGF-1 was localized with neuronal cell bodies in DRG. IGF-1 knockdown caused a reduction in mechanical allodynia. The upregulation of IGF-1 might be a key factor in painful radiculopathy induced by mechanical factors.

Insulin-like growth factor 1 mediates 5-fluorouracil chemoresistance in esophageal carcinoma cells through increasing survivin stability

Insulin-like growth factor 1 (IGF-1) inhibits 5-fluorouracil (5-Fu)-induced apoptosis in esophageal carcinoma cells; however, the mechanisms for IGF-1-induced 5-Fu chemoresistance remain unknown. In the human esophageal carcinoma cell line, CE48T/VGH, we show that IGF-1 up-regulated survivin expression at the post-transcriptional level and this up-regulation is mediated by both the PI3-K/Akt and casein kinase 2 signaling pathways. We then examine whether IGF-1-induced 5-Fu chemoresistance is mediated through up-regulation of survivin. Ectopic expression of survivin inhibits 5-Fu-induced apoptosis; furthermore, the abolition of survivin expression sensitizes cells to 5-Fu treatment and prevents the anti-apoptotic function of IGF-1 in esophageal carcinoma cell lines. We also found that ectopic expression of survivin or treatment with IGF-1 inhibits the release of Smac/DIABLO and caspases activation after 5-Fu treatment. Our results strongly suggest that IGF-1 inhibits 5-Fu induced apoptosis through increasing survivin levels, which prevents Smac/DIABLO release and blocks the activation of caspases. Therefore, up-regulation of IGF-1 and survivin would seem to be responsible for 5-Fu chemoresistance in esophageal cancer patients and these factors may be the valuable predictors of 5-Fu chemoresistance in esophageal carcinoma.

Growth Factor Preconditioning Increases the Function of Diabetes-Impaired Mesenchymal Stem Cells

Bone marrow-derived mesenchymal stem cells (MSCs) possess multilineage differentiation potential and can be used for the treatment of diabetic heart failure. However, hyperglycemia can affect the function of MSCs adversely and merits the requirement for a strategy to correct this anomaly. MSCs were isolated from the tibias and femurs of C57BL/6 wild-type mice at 60 days after induction of diabetes by streptozotocin. MSCs were characterized by flow cytometry for CD44 (97.7%), CD90 (95.4%), and CD105 (92.3%) markers and were preconditioned with insulin-like growth factor-1 (IGF-1) (50 ng/mL) and fibroblast growth factor-2 (FGF-2) (50 ng/mL) in combination for 1 h in serum-free Iscove's modified Dulbecco's medium. This was followed by hypoxic and high glucose insults to mimic diabetic heart microenvironment and to study the effect of preconditioning. Diabetic MSCs after treatment showed upregulation of IGF-1, FGF-2, Akt, GATA-4, and Nkx 2.5 and downregulation of p16(INK4a), p66(shc), p53, Bax, and Bak. Under hypoxic stress, preconditioned diabetic MSCs showed high superoxide dismutase activity (52.3%) compared with untreated cells (36.9%). This was concomitant with low numbers of annexin-V-positive cells, high in vitro tube-forming ability, and high chemotactic mobility to stromal cell-derived factor-1α after preconditioning in diabetic MSCs. Upregulation of Ang-I and VEGF and downregulation of p16(INK4a) were also observed in preconditioned cells under conditions of high glucose insult. Therefore, preconditioning with IGF-1 and FGF-2 in combination represents a novel strategy to augment MSC function affected by diabetes and holds significance for future strategies to treat diabetic heart failure.

Down-regulation of achaete-scute complex homolog 1 (ASCL1) in neuroblastoma cells induces up-regulation of insulin-like growth factor 2 (IGF2)

Neuroblastoma (NB) is the most common extra-cranial solid pediatric tumor. The prognosis of patients with NB has been improved during the last decades. However, treatment results for patients with advanced tumor stages are still unsatisfying. NB cells are characterized by a high tendency for spontaneous or induced differentiation. During differentiation, down-regulation of the basic helix-loop-helix transcription factor achaete-scute complex homolog 1 (ASCL1) has been observed but the consequences of ASCL1 down-regulation have not been elucidated. We used RNA interference to knock-down ASCL1 in NB cells. DNA microarray analysis was used for the identification of ASCL1-regulated genes. Furthermore, conventional and quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used for validation of ASCL1-regulated genes. Down-regulation of ASCL1 influenced the expression of several genes. After down-regulation of ASCL1, we observed very high expression of insulin-like growth factor 2 (IGF2), a factor that is known to be induced during differentiation of NB cells. RT-PCR indicated up-regulation of multiple IGF2 transcript variants after ASCL1 knock-down. Our data suggest that the ASCL1-pathway is responsible for the up-regulation of IGF2 during NB differentiation.