Insulin-like Growth Factor-1 Receptor Expression Research Articles

Addition of zoledronic acid to neoadjuvant chemotherapy is not beneficial in patients with HER2-negative stage II/III breast cancer: 5-year survival analysis of the NEOZOTAC trial (BOOG 2010-01)

BackgroundAdjuvant bisphosphonates are associated with improved breast cancer survival in postmenopausal patients. Addition of zoledronic acid (ZA) to neoadjuvant chemotherapy did not improve pathological complete response in the phase III NEOZOTAC trial. Here we report the results of the secondary endpoints, disease-free survival, (DFS) and overall survival (OS).Patients and methodsPatients with HER2-negative, stage II/III breast cancer were randomized to receive the standard 6 cycles of neoadjuvant TAC (docetaxel/doxorubicin/cyclophosphamide) chemotherapy with or without 4 mg intravenous (IV) ZA administered within 24 h of chemotherapy. This was repeated every 21 days for 6 cycles. Cox regression models were used to evaluate the effect of ZA and covariates on DFS and OS. Regression models were used to examine the association between insulin, glucose, insulin growth factor-1 (IGF-1) levels, and IGF-1 receptor (IGF-1R) expression with survival outcomes.ResultsTwo hundred forty-six women were eligible for inclusion. After a median follow-up of 6.4 years, OS for all patients was significantly worse for those who received ZA (HR 0.468, 95% CI 0.226–0.967, P = 0.040). DFS was not significantly different between the treatment arms (HR 0.656, 95% CI 0.371–1.160, P = 0.147). In a subgroup analysis of postmenopausal women, no significant difference in DFS or OS was found for those who received ZA compared with the control group (HR 0.464, 95% CI 0.176–1.222, P = 0.120; HR 0.539, 95% CI 0.228–1.273, P = 0.159, respectively). The subgroup analysis of premenopausal patients was not significantly different for DFS and OS ((HR 0.798, 95% CI 0.369–1.725, P = 0.565; HR 0.456, 95% CI 0.156–1.336, P = 0.152, respectively). Baseline IGF-1R expression was not significantly associated with DFS or OS. In a predefined additional study, lower serum levels of insulin were associated with improved DFS (HR 1.025, 95% CI 1.005–1.045, P = 0.014).ConclusionsOur results suggest that ZA in combination with neoadjuvant chemotherapy was associated with a worse OS in breast cancer (both pre- and postmenopausal patients). However, in a subgroup analysis of postmenopausal patients, ZA treatment was not associated with DFS or OS. Also, DFS was not significantly different between both groups. IGF-1R expression in tumor tissue before and after neoadjuvant treatment did not predict survival.Trial registrationClinicalTrials.gov, NCT01099436, April 2010.

Higher IL-6 peri-tumoural expression is associated with gastro-intestinal neuroendocrine tumour progression

An association of well-differentiated gastroenteropancreatic neuroendocrine tumours (WD GEP NETs) with metabolic syndrome (MetS) was recently described. Yet no molecular mechanisms linking the two conditions are known. This study's aim was to identify putative molecular signatures linking WD GEP NETs and MetS to gain further insight into potential mechanisms for this association. Patients with WD GEP NETs (n=39), pancreatic (panNET) and gastro-intestinal (GI-NET), were clinically evaluated for presence of MetS. WD GEP NETs immunohistochemistry staining for Forkhead box protein M1 (FOXM1), insulin growth factor 1 receptor (IGF1R), Ki-67 and interleukin 6 (IL-6) was performed and quantified by computerised morphometric analysis. FOXM1, Ki-67, IGF1R or IL-6 expression in WD GEP NETs was not influenced by the presence of MetS. IL-6 peritumoural expression was higher in GI-NETs of patients with low HDL cholesterol (0.018±0.005% vs 0.030±0.005%, p=0.02). In GI-NETs, a higher IL-6 expression was also associated with disease progression (0.026±0.004% vs 0.016±0.002%, p=0.03). In WD GEP-NETs, MetS did not influence FOXM1, IGF1R and IL-6 expression. In GI-NETs, IL-6 expression was influenced by the MetS feature low HDL, and positively associated with disease progression. These data suggest that local and systemic inflammatory status can potentially modulate GI-NET behaviour.

Pathogenetic implications of early growth response 1 in Ewing sarcoma

Ewing sarcoma (ES) is the second most common primary malignant bone tumour, mainly occurs in children and adolescents, and has an overwhelming mortality. Despite extensive studies, few effective oncogenic signals have been described. Therefore, it is crucial to exploit novel pathognomonic factors and targetable biomarkers for ES patients. Based on previous studies, we speculate that insulin-like growth factor 1 receptor (IGF1R), which is upregulated by early growth response 1 (EGR1), may play a pivotal role in strengthening the downward transmission of IGF1 cascades. Therefore, in this study, we concentrated on determining the pathogenetic contribution of EGR1 in diverse ES cells. This report is the first to study the pathogenic role of EGR1 in ES. ES cells were cultured and transfected with Stealth RNAi human EGR1 small interfering RNA (siRNA) or negative control. Cell proliferation and invasion potential were measured. mRNA and protein expression of EGR1, IGF1R, and EWS-FLI1 also were assessed. In all EGR1 siRNA-transfected cells (SK-ES-1, RD-ES, and HS863.T), cell proliferation and invasive potential decreased significantly in EGR1 siRNA-transfected ES cells. mRNA and protein expression for EGR1, IGF1R, and EWS-FLI1 were also significantly reduced. In conclusion, EGR1 upregulated IGF1R expression and enhanced the expression of the oncogenic fusion protein EWS-FLI1. The EWS-FLI1/EGR1/IGF1R cascade combined with the previously confirmed pathways can form a speculative circuit, implicating positive feedback for tumourigenesis in ES. Therefore, EGR1 inhibitors are expected to be useful for the treatment of ES by preventing oncogenic IGF1/IGF1R expression.

Long Noncoding RNA-Maternally Expressed Gene 3 Contributes to Hypoxic Pulmonary Hypertension.

The expression and function of long noncoding RNAs (lncRNAs) in the development of hypoxic pulmonary hypertension (HPH), especially in the proliferation of pulmonary artery smooth muscle cells (PASMCs), are largely unknown. Herein, we examined the expression and role of lncRNA-maternally expressed gene 3 (lncRNA-MEG3) in HPH. lncRNA-MEG3 was significantly increased and primarily localized in the cytoplasm of hypoxic PASMCs. lncRNA-MEG3 knockdown by lung-specific delivery of small interfering RNAs (siRNAs) significantly inhibited the development of HPH invivo. Silencing of lncRNA-MEG3 by siRNAs and gapmers attenuated proliferation and cell-cycle progression in both PASMCs from idiopathic pulmonary arterial hypertension (iPAH) patients (iPAH-PASMCs) and hypoxia-exposed PASMCs invitro. Mechanistically, we found that lncRNA-MEG3 interacts with and leads to the degradation of microRNA-328-3p (miR-328-3p), leading to upregulation of insulin-like growth factor 1 receptor (IGF1R). Additionally, higher expression of lncRNA-MEG3 and IGF1R and lower expression of miR-328-3p were observed in iPAH-PASMCs and relevant HPH models. These data provide insights into the contribution of lncRNA-MEG3 to HPH. Upregulation of lncRNA-MEG3 sequesters cytoplasmic miR-328-3p, eventually leading to expression of IGF1R, revealing a regulatory mechanism by lncRNAs in hypoxia-induced PASMC proliferation.

Antitumor effect of insulin-like growth factor-1 receptor inhibition in head and neck squamous cell carcinoma.

The insulin-like growth factor-1 receptor (IGF1R) has been implicated in therapeutic resistance in head and neck squamous cell carcinoma (HNSCC), and small molecule tyrosine kinase inhibitors (TKIs) of IGF1R activity may have anticancer activity. Therefore, the relationship between survival and IGF1R expression was assessed for oral cavity (OC) cancer, and the antitumor effects of two IGF1R-TKIs, OSI-906 and BMS-754807, were evaluated in HNSCC cell lines in vitro. Clinical outcome data and tissue microarray immunohistochemistry were used to generate IGF1R expression-specific survival curves. Immunoblot, alamarBlue proliferation assay, trypan blue exclusion viability test, clonogenic assay, flow cytometry, and reverse phase protein array (RPPA) were used to evaluate in vitro responses to IGF1R-TKIs. For patients with stage III/IV OCSCC, higher IGF1R expression was associated with poorer overall 5-year survival (P = 0.029). Both BMS-754807 and OSI-906 caused dose-dependent inhibition of IGF1R and Akt phosphorylation and inhibited proliferation; BMS-754807 was more potent than OSI-906. Both drugs reduced HNSCC cell viability; only OSI-906 was able to eliminate all viable cells at 10 μM. The two drugs similarly inhibited clonogenic cell survival. At 1 μM, only BMS-754807 caused a fourfold increase in the basal apoptotic rate. RPPA demonstrated broad effects of both drugs on canonical IGF1R signaling pathways and also inhibition of human epidermal growth factor receptor-3 (HER3), Src, paxillin, and ezrin phosphorylation. OSI-906 and BMS-754807 inhibit IGF1R activity in HNSCC cell lines with reduction in prosurvival and proliferative signaling and with concomitant antiproliferative and proapoptotic effects. Such antagonists may have utility as adjuvants to existing therapies for HNSCC. NA Laryngoscope, 130:1470-1478, 2020.

IGF1R as druggable target mediating PI3K-δ inhibitor resistance in a murine model of chronic lymphocytic leukemia

AbstractTargeted therapy is revolutionizing the treatment of cancers, but resistance evolves against these therapies and derogates their success. The phosphatidylinositol 3-kinase delta (PI3K-δ) inhibitor idelalisib has been approved for treatment of chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma, but the mechanisms conferring resistance in a subset of patients are unknown. Here, we modeled resistance to PI3K-δ inhibitor in vivo using a serial tumor transfer and treatment scheme in mice. Whole-exome sequencing did not identify any recurrent mutation explaining resistance to PI3K-δ inhibitor. In the murine model, resistance to PI3K-δ inhibitor occurred as a result of a signaling switch mediated by consistent and functionally relevant activation of insulin-like growth factor 1 receptor (IGF1R), resulting in enhanced MAPK signaling in the resistant tumors. Overexpression of IGF1R in vitro demonstrated its prominent role in PI3K-δ inhibitor resistance. IGF1R upregulation in PI3K-δ inhibitor–resistant tumors was mediated by functional activation and enhanced nuclear localization of forkhead box protein O1 transcription factors and glycogen synthase kinase 3β. In human CLL, high IGF1R expression was associated with trisomy 12. CLL cells from an idelalisib-treated patient showed decreased sensitivity to idelalisib in vitro concomitant with enhanced MAPK signaling and strong upregulation of IGF1R upon idelalisib exposure. Thus, our results highlight that alternative signaling cascades play a predominant role in the resistance and survival of cancer cells under PI3K-δ inhibition. We also demonstrate that these pathway alterations can serve as therapeutic targets, because inhibition of IGF1R offered efficacious salvage treatment of PI3K-δ inhibitor–resistant tumors in vitro and in vivo.

Detection and targeting insulin growth factor receptor type 2 (IGF2R) in osteosarcoma PDX in mouse models and in canine osteosarcoma tumors

Osteosarcoma (OS) represents 3.4% of all childhood cancers with overall survival of 70% not improving in 30 years. The consistent surface overexpression of insulin-like growth factor-2 receptor (IGF2R) has been reported in commercial and patient-derived xenograft (PDX) OS cell lines. We aimed to assess efficacy and safety of treating PDX and commercial OS tumors in mice with radiolabeled antibody to IGF2R and to investigate IGF2R expression on canine OS tumors. IGF2R expression on human commercial lines 143B and SaOS2 and PDX lines OS-17, OS-33 and OS-31 was evaluated by FACS. The biodistribution and microSPECT/CT imaging with 111Indium-2G11 mAb was performed in 143B and OS-17 tumor-bearing SCID mice and followed by radioimmunotherapy (RIT) with 177Lutetium-2G11 and safety evaluation. IGF2R expression in randomly selected canine OS tumors was measured by immunohistochemistry. All OS cell lines expressed IGF2R. Biodistribution and microSPECT/CT revealed selective uptake of 2G11 mAb in 143B and OS-17 xenografts. RIT significantly slowed down the growth of OS-17 and 143B tumors without local and systemic toxicity. Canine OS tumors expressed IGF2R. This study demonstrates the feasibility of targeting IGF2R on OS in PDX and spontaneous canine tumors and sets the stage for further development of RIT of OS using comparative oncology.

Upregulation of Insulin-Like Growth Factor-1 Receptor (IGF-1R) Reverses the Inhibitory Effect of Let-7g-5p on Migration and Invasion of Nasopharyngeal Carcinoma.

BackgroundLet-7 microRNAs (miRNAs) have the effects of inhibiting tumor growth and metastasis, however, the research in nasopharyngeal carcinoma (NPC) is limited. This study focused on the effects of Let-7 on NPC migration and invasion and the mechanism of action.Material/MethodsPlasmid transfection was used to upregulate the expression levels of Let-7g-5p and insulin-like growth factor-1 receptor (IGF-1R). Cell counting kit-8 (CCK-8) assay was applied to test the cell viability. Scratch assay and Transwell assay were performed to detect the migration and invasion abilities. Bioinformatics prediction and luciferase reporter assay were used to determine and verify the downstream target genes for Let-7g-5p. Protein and mRNA were detected by western blot and real-time quantitative polymerase chain reaction (RT-qPCR), respectively.ResultsLet-7g-5p was under-expressed in human NPC cells. Overexpression of Let-7g-5p could inhibit cell viability and inhibit the migration and invasion of SUNE1 cells. The dual-luciferase reporter assay showed that IGF-1R was a direct target gene of Let-7g-5p, which was directly regulated IGF-1R expression by 3′UTR. Let-7g-5p overexpression could inhibit the expression of IGF-1R gene, and upregulation of IGF-1R gene expression reversed the inhibitory effect of Let-7g-5p on cell viability and epithelial-mesenchymal transition processes.ConclusionsLet-7g-5p is lowly expressed in NPC and it was the first to discover that IGF-1R was a target gene of let-7g-5p in NPC. Upregulation of IGF-1R reversed the inhibitory effect of Let-7g-5p on epithelial-mesenchymal transition.

Enhancer of zeste 2 polycomb repressive complex 2 subunit promotes sorafenib resistance of hepatocellular carcinoma though insulin-like growth factor 1 receptor.

Enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) is the core component of polycomb repressive complex 2 and is overexpressed in several types of solid malignancies. It has been reported that EZH2 contributes to sorafenib resistance of hepatocellular carcinoma (HCC). However, its underlying molecular mechanisms remain unknown. In this study, we demonstrated that EZH2 induced sorafenib resistance of HCC cells in vitro. Mechanistically, EZH2 was a potent regulator of insulin-like growth factor 1 receptor (IGF1R) and EZH2-modulated IGF1R expression by directly transcriptionally repressing a set of microRNAs (miRNAs) including miR-101, miR-122, miR-125b, and miR-139. These miRNAs were required for EZH2-mediated sorafenib resistance by promoting IGF1R expression. Surprisingly, IGF1R inhibitors significantly reversed EZH2-induced sorafenib resistance. Collectively, we proposed a novel model for an EZH2 - miRNAs - IGF1R regulatory axis, which might provide insights into how EZH2 contributes to sorafenib resistance in HCC.

Abstract 78: IGF-1R inhibition activates p70S6K1 to promote survival via MEK1/2 activation in colon cancer cells

Abstract The insulin-like growth factor 1 receptor (IGF-1R) is a heterotetramer with tyrosine kinase activity, composed of two α subunits containing the ligand-binding site and two β subunits harboring the tyrosine kinase activity. Upon binding with ligands (IGF-1, IGF-2, and insulin), IGF-1R leads to activation of downstream pathways including PI3-K/AKT and Ras/MAPK, two frequently activated pathways for promoting cell survival and proliferation in various cancers including colorectal cancer. Immunohistochemical studies revealed that IGF-1R is over-expressed in colorectal cancer tissues compared to the adjacent normal tissues. Most importantly, a higher expression of IGF-1R is associated with a higher grade and stage in colorectal cancer patients. Since the IGF-1R signaling pathway plays an essential role in development, maintenance, and survival of tumors, many small molecule compounds and antibodies targeting IGF-1R have been developed. Unfortunately, these anti-IGF-1R agents demonstrate very limited efficacy in clinical trials, suggesting the existence of a mechanism to overcome the inhibitory effect of IGF-1R in cancer cells. In this study, we aim to understand the resistance mechanism of IGF-1R inhibition in colon cancer cells. Prolonged treatment of IGF-1R resistant colon cancer cells with IGF-1R inhibitors (OSI-906, BMS-754807, and GSK1838705A) stimulates p70S6K1 activation, a well-known kinase signaling for cell survival. We also found that p70S6K1 activation is independent of mutation of K-RAS and PIK3CA, frequently occurring in colorectal cancer. Genetic knockdown or pharmacologic inhibition of p70S6K1 efficiently suppresses cell viability in response to IGF-1R inhibition, indicating that p70S6K1 activation contributes to the survival of IGF-1R inhibitor-treated cells. In addition to the increased phosphorylation of p70S6K1, phosphorylation of MEK1/2 is also elevated in colon cancer cells with prolonged inhibition of IGF-1R. Knockdown of MEK1/2 results in reduction of p70S6K1 activation in response to IGF-1R inhibition and subsequently increases apoptosis, suggesting that MEK1/2 is involved in p70S6K1 activation for survival. Furthermore, the combination of BMS754807 and U0126, a MEK1/2 inhibitor, effectively decreases the cell viability and increases apoptosis. Our data suggest that inhibition of MEK1/2 enhances the anti-proliferation effects of IGF-1R inhibitors, pointing out a new direction for overcoming the resistance of IGF-1R inhibition in colorectal cancer. Citation Format: Qing Wang, Hsin-Sheng Yang. IGF-1R inhibition activates p70S6K1 to promote survival via MEK1/2 activation in colon cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 78.

Effects of branched-chain volatile fatty acids and fibrolytic enzyme on rumen development in pre- and post-weaned Holstein dairy calves

The study evaluated the effects of branched-chain volatile fatty acids (BCVFA) and fibrolytic enzyme (FE) on rumen development in calves. Forty Holstein male calves at the same ages (15 ± 2.5 days of age) and weights (45 ± 3.3 kg of body weight [BW]) were assigned randomly to four groups with a 2 × 2 factorial arrangement of treatments. Supplemental BCVFA (0 g/d or 18 g/d) and FE (0 g/d or 1.83 g/d) were fed to calves. Data were analyzed as a 2 × 2 factorial arrangement random design by the mixed procedure of SAS. The BCVFA × FE interaction was observed for ruminal propionate, blood growth hormone (GH) and insulin-like growth factor-1 (IGF-1), and GH receptor (GHR) and IGF-1 receptor (IGF-1R) expression in the rumen mucosa. Dry matter intake was higher for BCVFA addition. The higher average daily gain and ruminal volatile fatty acids were observed for BCVFA or FE addition. Stomach weight and the length and width of rumen papillae were higher for BCVFA addition. The higher expression of GHR, IGF-1R and 3-hydroxy-3-methylglutaryl-CoA synthase 1 in rumen mucosa, and blood GH and IGF-1 were observed with BCVFA or FE addition. Blood β-hydroxybutyrate and acetoacetate were higher for BCVFA addition. The results indicated that rumen development was promoted by BCVFA, but was not affected with FE addition in calves.

Exendin-4 enhances proliferation of senescent osteoblasts through activation of the IGF-1/IGF-1R signaling pathway

A growing body of evidence indicates that treatment with glucagon-like peptide-1 (GLP-1) receptor agonists can be beneficial for patients with osteoporosis. However, the underlying mechanism by which GLP-1 receptor agonists improve osteoporosis remains unclear. In this study, we assessed the anti-osteoporosis effects of Exendin-4, a highly potent GLP-1 receptor agonist, using a rat senescent osteoblast model. We found that Exendin-4 improved proliferation of senescent osteoblasts, as indicated by MTT assay and ALP activity detection. RT-qPCR revealed that Exendin-4 up-regulated the expression of bone metabolism genes (OPG, RANKL, BGP) and down-regulated the expression of aging-related genes (p16, p21, p53). Meanwhile, we observed a sustained increase in IGF-1 receptor (IGF-1R) expression, and not GLP-1 receptor (GLP-1R) expression, in senescent osteoblasts treated with Exendin-4. Furthermore, intervention with Exendin-4 in senescent osteoblasts increased IGF-1, p-PI3K, and p-Akt protein levels, as shown by western blot analysis. Finally, downregulation of IGF-1 by RNAi inhibited the anti-osteoporosis effects of Exendin-4, which is associated with the IGF-1/PI3K/Akt signaling pathway. In summary, these results indicate that the GLP-1 receptor agonist Exendin-4 promotes proliferation of senescent osteoblasts by up-regulating IGF-1R expression and activating the IGF-1/PI3K/Akt signaling pathway, thereby preventing senile osteoporosis.

Long non-coding RNA deleted in lymphocytic leukaemia 1 promotes hepatocellular carcinoma progression by sponging miR-133a to regulate IGF-1R expression.

Long non‐coding RNA (lncRNA) deleted in lymphocytic leukaemia 1 (DLEU1) was reported to be involved in the occurrence and development of multiple cancers. However, the exact expression, biological function and underlying mechanism of DLEU1 in hepatocellular carcinoma (HCC) remain unclear. In this study, real‐time quantitative polymerase chain reaction (qRT‐PCR) in HCC tissues and cell lines revealed that DLEU1 expression was up‐regulated, and the increased DLEU1 was closely associated with advanced tumour‐node‐metastasis stage, vascular metastasis and poor overall survival. Function experiments showed that knockdown of DLEU1 significantly inhibited HCC cell proliferation, colony formation, migration and invasion, and suppressed epithelial to mesenchymal transition (EMT) process via increasing the expression of E‐cadherin and decreasing the expression of N‐cadherin and Vimentin. Luciferase reporter gene assay and RNA immunoprecipitation (RIP) assay demonstrated that DLEU1 could sponge miR‐133a. Moreover, miR‐133a inhibition significantly reversed the suppression effects of DLEU1 knockdown on HCC cells. Besides, we found that silenced DLEU1 significantly decreased insulin‐like growth factor 1 receptor (IGF‐1R) expression (a target of miR‐133a) and its downstream signal PI3K/AKT pathway in HCC cells, while miR‐133a inhibitor partially reversed this trend. Furthermore, DLEU1 knockdown impaired tumour growth in vivo by regulating miR‐133a/IGF‐1R axis. Collectively, these findings indicate that DLEU1 promoted HCC progression by sponging miR‐133a to regulate IGF‐1R expression. Deleted in lymphocytic leukaemia 1/miR‐133a/IGF‐1R axis may be a novel target for treatment of HCC.

MicroRNA‑877 inhibits cell proliferation and invasion in non‑small cell lung cancer by directly targeting IGF‑1R

MicroRNAs (miRNAs/miRs) are frequently differentially expressed in non-small cell lung cancer (NSCLC), and differential miRNAs expression may be closely associated with NSCLC genesis and development. Therefore, an in-depth investigation of the cancer-associated miRNAs that are crucial for NSCLC pathogenesis may provide effective therapeutic targets for patients with this aggressive malignant tumor type. The expression levels and roles of miR-877 have been well studied in hepatocellular carcinoma and renal cell carcinoma. However, the expression pattern and functions of miR-877 in NSCLC as well as associated underlying mechanisms, to the best of our knowledge, have not yet been investigated. The present study revealed that miR-877 expression was downregulated in NSCLC tissues and cell lines. Low miR-877 expression was significantly associated with TNM stage and distant metastasis in patients with NSCLC. Functional experiments demonstrated that recovery of miR-877 expression restricted the proliferation and invasion of NSCLC cells. In addition, bioinformatics analysis predicted insulin-like growth factor 1 receptor (IGF-1R) as a potential target of miR-877. Luciferase reporter assays, reverse transcription-quantitative PCR and western blot analysis further validated that IGF-1R was a direct target of miR-877 in NSCLC. Furthermore, IGF-1R expression was markedly upregulated in NSCLC tissues, and exhibited an inverse correlation with miR-877 expression. Additionally, IGF-1R overexpression reversed the inhibitory effects in NSCLC cells caused by miR-877 upregulation. These findings demonstrated that miR-877 attenuated NSCLC cell proliferation and invasion, at least partly, by downregulating IGF-1R expression, thereby providing an new candidate biomarker for the diagnosis and therapy of patients with NSCLC.

Selective receptor-mediated impairment of growth factor activity in neonatal- and X-linked adrenoleukodystrophy patients.

Background Neonatal adrenoleukodystrophy (n-ALD) and X-linked ALD (X-ALD) patients present with demyelination, poor growth and progressive mental retardation. Growth factors are known to play a vital role in the development of children. Objective To examine the mitogenic activity of various growth factors in skin fibroblasts from n-ALD and X-ALD patients. Methods Skin fibroblast cultures from n-ALD and X-ALD patients, and controls were treated with 50 ng/mL of platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF) or insulin-like growth factor-1 (IGF-1) to examine DNA synthesis by 5-bromo-2'-deoxyuridine (BrdU) incorporation. Expression of receptors for PDGF, bFGF and IGF-1 was measured by western blotting. Serum levels of IGF-1 were assayed by enzyme-linked immunosorbent assay (ELISA). Results Fibroblasts from n-ALD and X-ALD patients had significantly (p < 0.01) less BrdU incorporation in response to fetal bovine serum (FBS). The mitogenic effect of PDGF, bFGF and IGF-1 was significantly lower in n-ALD as compared to control and X-ALD cells. X-ALD cells showed significant impairment in IGF-1-induced DNA synthesis. Expression of the FGF receptor (FGF-R) was significantly reduced in n-ALD cells. PDGF receptor remained unaffected, and IGF-1 receptor (IGF-1R) expression and serum IGF-1 levels were significantly (p < 0.01) reduced in n-ALD and X-ALD patients as compared to controls. Conclusions Growth factor activity differs in n-ALD and X-ALD patients, with marked impairment of IGF-1 function through receptor down-regulation.

Seasonal expressions of growth hormone receptor, insulin-like growth factor 1 and insulin-like growth factor 1 receptor in the scented glands of the muskrats (Ondatra zibethicus)

The growth hormone (GH)/insulin-like growth factor-1 (IGF-1) system plays an important role in regulating the cellular growth and organ development. The present study investigated the seasonal expressions of growth hormone receptor (GHR), IGF-1 and insulin-like growth factor 1 receptor (IGF-1R) in the scented glands of the muskrats. Morphological changes in the scented glands of the muskrats were observed significantly between the breeding and non-breeding seasons. Immunohistochemically, the expressions of GH, GHR, IGF-1 and IGF-1R were found in glandular cells and epithelial cells of the scented glands in both seasons. The protein and mRNA expression levels of GHR, IGF-1 and IGF-1R in the scented glands during the breeding season were noticeably higher than those of the non-breeding season. In parallel, the levels of GH and IGF-1 in the sera and scented glands were remarkably higher during the breeding season. In addition, small RNA sequencing showed that the predicted targets of the significantly changed hsa-miR-5100 and mmu-miR-6937-5p might regulate the expressions of Ghr, Igf-1 or Igf-1r. These results suggested that the morphological changes in the scented glands of the muskrats during the different seasons might be related to the expression levels of GHR, IGF-1 and IGF-1R. Meanwhile, GHR/IGF-1 system might regulate the scented glandular functions via endocrine or autocrine/paracrine manners.

CircRASSF2 promotes laryngeal squamous cell carcinoma progression by regulating the miR-302b-3p/IGF-1R axis.

Background: Circular RNAs (circRNAs) are a class of non-coding RNAs (ncRNAs) broadly expressed in cells of various species. However, the molecular mechanisms that link circRNAs with laryngeal squamous cell carcinoma (LSCC) are not well understood. In the present study, we attempted to provide novel basis for targeted therapy for LSCC from the aspect of circRNA-microRNA (miRNA)-mRNA interaction.Methods: We investigated the expression of circRNAs in three paired LSCC tissues and adjacent non-tumor tissues by microarray analysis. Differentially expressed circRNAs were identified between LSCC tissues and non-cancerous matched tissues, including 527 up-regulated circRNAs and 414 down-regulated circRNAs. We focused on hsa_circ_0059354, which is located on chromosome 20 and derived from RASSF2, and thus we named it circRASSF2.Results: circRASSF2 was found to be significantly up-regulated in LSCC tissues and LSCC cell lines compared with paired adjacent non-tumorous tissues and normal cells. Moreover, knockdown of circRASSF2 significantly inhibited cell proliferation and migration in vitro, which was blocked by miR-302b-3p inhibitor. Bioinformatics analysis predicted that there is a circRASSF2/miR-302b-3p/ insulin-like growth factor 1 receptor (IGF-1R) axis in LSCC progression. Dual-luciferase reporter system validated the direct interaction of circRASSF2, miR-302b-3p, and IGF-1R. Western blot verified that inhibition of circRASSF2 decreased IGF-1R expression. Furthermore, silencing circRASSF2 suppressed LSCC growth in vivo Importantly, we demonstrated that circRASSF2 was up-regulated in serum exosomes from LSCC patients. Altogether, silencing circRASSF2 suppresses progression of LSCC by interacting with miR-302b-3p and decreasing inhibiting IGF-1R expression.Conclusion: In conclusion, these data suggest that circRASSF2 is a central component linking circRNAs to progression of LSCC via an miR-302b-3p/IGF-1R axis.

MicroRNA-15b participates in the development of peripheral arterial disease by modulating the growth of vascular smooth muscle cells.

As an atherosclerotic disease, the process of peripheral arterial disease (PAD) is complicated and includes the abnormal proliferation of vascular smooth muscle. The current study aimed to determine the role of microRNA-15b (miR-15b) in the development of PAD and its associated mechanisms. Human vascular smooth muscle cells (hVSMCs) were used in the current study. To assess the effects of miR-15b on hVSMCs, miR-15b was up- or downregulated in hVSMCs using miR-15b mimics or miR-15b inhibitors respectively. Cell viability, migration and apoptosis were then determined via MTT, transwell and flow cytometry assays, respectively. TargetScan bioinformatics software was utilized to predict the targets of miR-15b, and the binding sites between insulin growth factor 1 receptor (IGF1R) and miR-15b were confirmed by dual-luciferase reporter assay. The results reveled that the miR-15b mimic significantly reduced hVSMC cell viability and migration, and promoted cell apoptosis. However, the opposite effect was observed following miR-15b inhibitor transfection. It was also determined that miR-15b directly targeted IGF1R and negatively regulated its expression in hVSMCs. Additionally, the results demonstrated that the miR-15b mimic inhibited the PI3K/AKT signaling pathway in hVSMCs, whereas the miR-15b inhibitor promoted it. Furthermore, the results indicated that the effect of the miR-15b mimic on hVSMCs was reversed by IGF1R overexpression. In conclusion, the data indicated that miR-15b participated in the occurrence and development of PAD by modulating hVSMC proliferation, apoptosis and migration via the regulation of IGF1R expression.

Retraction: Corrigendum: Insulin-like growth factor-I receptor is suppressed through transcriptional repression and mRNA destabilization by a novel energy restriction-mimetic agent.

Insulin-like growth factor-I receptor (IGF-IR) represents one of the major targets by which dietary or chemically induced energy restriction mediates chemopreventive effects in animal tumor models. However, the mechanism underlying this cellular response remains unclear. In the course of investigating the suppressive effect of the energy restriction-mimetic agent CG-5 on IGF-IR expression in prostate cancer cells, we identified a novel posttranscriptional mechanism by which the RNA-binding protein human antigen R (HuR) regulates IGF-IR expression through messenger RNA (mRNA) stabilization. Previously, we demonstrated that Sp1 and HuR proteins were concomitantly targeted for ubiquitin-dependent degradation by β-transducin repeat-containing protein in response to CG-5. Although this loss of Sp1 expression contributed to CG-5-mediated IGF-IR downregulation, enforced specific protein 1 (Sp1) expression could only partially protect cells from the drug effect. The small interfering RNA-mediated silencing of HuR suppressed IGF-IR expression by reducing mRNA stability, whereas ectopic HuR expression increased IGF-IR mRNA stability and protein expression and, when coexpressed with Sp1, blocked CG-5-mediated IGF-IR ablation. RNA pull-down and immunoprecipitation analyses indicated that HuR selectively bound to the distal region of the IGF-IR 3′ untranslated region (UTR), whereas no interaction with the 5′UTR was noted. Evaluation of a series of truncated HuR mutants revealed that the RNA recognition motifs (RRM2 and RRM3) were involved in IGF-IR 3′UTR binding and the consequent increase in IGF-IR mRNA stability. Although these data contrast with a previous report that HuR acted as a translation repressor of IGF-IR mRNA through 5′UTR binding, our finding is consistent with the reported oncogenic role of HuR in conferring stability to target mRNAs encoding tumor-promoting proteins.

Insulin-Like Growth Factor and SLC12A7 Dysregulation: A Novel Signaling Hallmark of Non-Functional Adrenocortical Carcinoma

Insulin-like growth factor (IGF) dysregulation and gene copy number variations (CNV) are hallmarks of adrenocortical carcinoma (ACC). The contribution of IGF CNVs in adrenal carcinogenesis has not been studied previously. In addition, studies demonstrating an association between SLC12A7 gene amplifications and enhanced metastatic behavior in ACC, as well as reported IGF-SLC12A7 signaling interactions in other cancers, suggest a potential IGF-SLC12A7 signaling circuitry in ACC. Here we investigate the potential complicity of IGF-SLC12A7 signaling in ACC. Insulin-like growth factor CNVs were determined by whole-exome sequencing analysis in an exploratory cohort of ACC. Quantitative polymerase chain reaction methods determined IGF1 and IGF2 expression levels and were evaluated for correlation with SLC12A7 expression and tumor characteristics. Insulin-like growth factor CNVs and expression patterns were compared with The Cancer Genome Atlas. Invitro studies determined the relationship of IGF and SLC12A7 co-expression in 2 ACC cell lines, SW-13 and NCI-H295R. Immunohistochemistry assessed IGF1 receptor (IGF1R) activation. The IGF1 gene was amplified in 9 of 19 ACC samples, similar to findings in The Cancer Genome Atlas database. The IGF1 overexpression was observed in 5 samples and was associated with SLC12A7 overexpression and non-functional, early-stage tumors (p < 0.05). In contrast, IGF2 overexpression was associated with larger tumors (p < 0.05). Invitro IGF treatment of ACC cell lines did not stimulate SLC12A7 expression, and endogenous overexpression and silencing of SLC12A7 significantly altered IGF1 and IGF1R expression without impacting other IGFs. The IGF1R activation was associated with IGF1 overexpression in ACC tumor samples. These findings indicate that IGF1 overexpression, caused in part by gene amplifications, is correlated with SLC12A7 overexpression in non-functional, early-stage ACCs, suggesting a potentially targeted IGF1-SLC12A7 therapeutic opportunity for these tumors.