Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

IGF-II is abundant in the nascent mesoderm of the gastrulating mouse embryo. Its function at this developmental stage is unknown. We investigated it by following the in vitro and in vivo differentiation of several androgenetic, biparental, parthenogenetic, and androgenetic Igf2 -/- murine ES cell lines; these cells differed in endogenous IGF-II levels because Igf2 is paternally expressed in the mouse embryo in most tissues. The expression of mesoderm markers and the subsequent formation of muscle structures were correlated with endogenous IGF-II level during teratoma formation and during in vitro differentiation. In addition, the absence of Igf2 in androgenetic Igf2 -/- ES cells led to a severe impairment of mesoderm development, demonstrating the dependence of the preferential mesoderm development of androgenetic ES cells upon Igf2 activity, among the numerous known imprinted genes. The addition of exogenous IGF-II to in vitro differentiation culture medium led to a specific increase in the expression of mesoderm markers. Thus, we propose a novel model in which the binding of IGF-II to its principal signaling receptor, IGF1R, at the surface of mesoderm precursor cells increases the formation of mesoderm cells.
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PMID:IGF-II promotes mesoderm formation. 1107 82

Neuronal apoptosis is considered to play a significant role in several neuropathological conditions. However, the molecular mechanisms underlying neuronal apoptosis are poorly understood. Insulin-like growth factor (IGF) signalling is considered to be an important regulator of neuronal differentiation, survival and apoptosis. We have examined the expression of two members of the IGF system, insulin-like growth factor binding protein 5 (IGFBP-5) and the type-1 IGF receptor (IGF1R), during apoptosis of rat cerebellar granule cells (CGCs) in vitro. We describe a prominent downregulation of IGFBP-5 mRNA and protein expression. We also show that IGF-I increases IGFBP-5 expression in CGCs and that the downregulation of IGFBP-5 mRNA can be suppressed by inhibiting mRNA synthesis with actinomycin D. The expression of IGF1R mRNA showed a transient upregulation during potassium chloride (KCl) deprivation induced apoptosis, in contrast to the IGF1R protein level, which was downregulated during KCl deprivation. Our results provide insight into the expression of IGF-related genes during neuronal apoptosis, and indicate that they mediate a protective response to the withdrawal of trophic stimulation. It seems that the expression of IGFBP-5 and IGF1R is regulated to maximize the availability of IGF and the activity of IGF-triggered survival signalling.
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PMID:Insulin-like growth factor binding protein 5 and type-1 insulin-like growth factor receptor are differentially regulated during apoptosis in cerebellar granule cells. 1114 73

The insulin-like growth factor (IGF) system exerts pleiotropic effects on mammalian cells. This review focuses on type I IGF receptor (IGF1R)-mediated signal transduction and its relevance in breast cancer. Upon activation by the IGFs, IGF1R, a transmembrane tyrosine kinase receptor, undergoes autophosphorylation, and then binds and phosphorylates additional signaling molecules. These intermediates initiate a series of downstream signaling events that are involved in multiple physiologic processes for cells. Recent data demonstrate that the IGF receptor system actively interacts with the estrogen receptor and integrin receptor systems. Cross-talk among these pathways regulates breast cancer proliferation, protection from cell death, and metastasis. Better understanding of IGF biochemical signaling pathways is of utmost importance for developing therapies for breast cancer.
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PMID:Tyrosine kinase signalling in breast cancer: insulin-like growth factors and their receptors in breast cancer. 1125 Jul 6

The insulin-like growth factor (IGF) system plays an important role in postnatal somatic and skeletal muscle growth in pigs. There is little information on the occurrence and distribution of components of the IGF system in postnatal porcine skeletal muscle. IGF-I, IGF receptor 1 (IGF1R) and the IGF-binding proteins IGFBP-1 and -3 in longissimus dorsi and triceps brachii were localized in muscle biopsies from 12 commercially crossbred pigs aged from 28 to 199 days as well as from the sire generation, by immunohistochemistry. Plasma IGF-I concentrations were also determined using radio-immunoassays. Unlike other species, IGF-I was localized in porcine skeletal muscle fibres. Staining intensity correlated with the highest plasma IGF-I levels and phases of intensive muscle growth from the 11th to 22nd week. The pattern of IGF1R immunostaining, which was strong, correlated with that of IGF-I, IGF1R was also localized in endomysial tissues. IGFBP-1 was not detected within muscle fibres, but was found in the endomysium and vessel walls, while IGFBP-3 was localized with IGF-1 and its receptor. Higher magnification revealed that IGF1R, IGFBP-3 and probably IGF-I appeared in the tubular system. Inhibitory as well as stimulating controls of IGFBP-1 and -3 on IGF functions are discussed, which may maintain a balance between autocrine growth promoting activities of IGF-I and IGF1R.
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PMID:Immunohistochemical detection of components of the insulin-like growth factor system during skeletal muscle growth in the pig. 1128 63

Our previous comparative genomic hybridization (CGH) study revealed a novel amplified region at 15q26 in two cell lines established from diffuse types of gastric cancer (GC). In this amplified region, FES and IGF1R, known targets on 15q26, were located telomeric to the amplicon in the two cell lines, HSC39 and 40A, suggesting that another tumor-associated gene exists in this region. While screening expressed sequence tags (ESTs) for novel genes in this region, we identified the IQGAP1 amplification. IQGAP1 has been reported to encode a ras GAP-related protein, and its interaction with cadherin and/or beta-catenin induces a dissociation of beta-catenin from the cadherin-catenin complex, one of the mechanisms for cell-cell adhesion. Northern and Western blot analyses revealed that amplification of this gene was accompanied by corresponding increases in mRNA and protein expression. Moreover, immunocytochemical staining showed that overexpressed IQGAP1 accumulated at the membrane, suggesting its colocalization with beta-catenin. Taken together, these findings suggest that IQGAP1 may be one of the target genes in the 15q26 amplicon correlated with a malignant phenotype of gastric cancer cells, such as diffuse and invasive characteristics, through the disruption of E-cadherin-mediated cell-cell adhesion.
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PMID:IQGAP1, a negative regulator of cell-cell adhesion, is upregulated by gene amplification at 15q26 in gastric cancer cell lines HSC39 and 40A. 1128 14

A major problem which is poorly understood in the management of bladder cancer is low sensitivity to chemotherapy and high recurrence after transurethral resection. Insulin-like growth factor 1 receptor (IGF-1R) signaling plays a very important role in progression, invasion and metastasis of bladder cancer cells. In this study, we investigated whether IGF-1R was involved in the growth stimulating activity and drug resistance of bladder cancer cells. The results showed: The mRNAs of IGF-1, IGF-2 and IGF-1R were strongly expressed in serum-free cultured T24 cell line, whereas normal urothelial cells did not express these factors/receptors or only in trace levels; T24 cell responded far better to growth stimulation by IGF-1 than did normal urothelial cells; blockage of IGF1R by antisense oligodeoxynucleotide (ODN) significantly inhibited the growth of T24 cell and enhanced sensitivity and apoptosis of T24 cells to mitomycin (MMC). These results suggested that blockage of IGF-IR signaling might potentially contribute to the treatment of bladder cancer cells which are insensitive to chemotherapy.
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PMID:Blockage of IGF-1R signaling sensitizes urinary bladder cancer cells to mitomycin-mediated cytotoxicity. 1145 42

The type 1 insulin-like growth factor receptor (IGF1R) is required for growth, tumorigenicity and protection from apoptosis. IGF1R overexpression is associated with radioresistance in breast cancer. We used antisense (AS) RNA to downregulate IGF1R expression in mouse melanoma cells. Cells expressing AS-IGF1R transcripts were more radiosensitive in vitro and in vivo than controls. Also they showed reduced radiation-induced p53 accumulation and p53 serine 18 phosphorylation, and radioresistant DNA synthesis. These changes were reminiscent of the cellular phenotype of the human genetic disorder ataxia-telangiectasia (A-T), caused by mutations in the ATM gene. Cellular Atm protein levels were lower in AS-IGF1R-transfected cells than in control cells, although there was no difference in Atm expression at the transcriptional level. AS-IGF1R cells had detectable basal Atm kinase activity, but failed to induce kinase activity after irradiation. This suggests that IGF1R signalling can modulate the function of Atm, and supports the concept of targeted IGF1R downregulation as a potential treatment for malignant melanoma and other radioresistant tumours.
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PMID:Downregulation of the type 1 insulin-like growth factor receptor in mouse melanoma cells is associated with enhanced radiosensitivity and impaired activation of Atm kinase. 1149 31

The epithelium to mesenchyme transition is thought to play a fundamental role during embryonic development and tumor progression. Loss of cell-cell adhesion and modification of both cell morphology and gene expression are the main events associated with this transition. There is a large amount of evidence suggesting that growth factors can initiate these events. Yet, the connection from growth factor induction to changes in cell adhesion and morphology is largely unknown. To elucidate this connection, we have investigated the action of IGF-II on E-cadherin/beta-catenin complex-mediated cell-cell adhesion and on beta-catenin/TCF-3 mediated gene expression. We can show that (1) IGF-II induces a rapid epithelium to mesenchymal transition; (2) IGF1R, the receptor for IGF-II, belongs to the same membrane complex as E-cadherin and beta-catenin; (3) IGF-II induces a redistribution of beta-catenin from the plasma membrane to the nucleus and an intracellular sequestration and degradation of E-cadherin; (4) IGF-II induces the transcription of beta-catenin/TCF-3 target genes. Based on the given case of IGF-II and E-cadherin/beta-catenin complex, this study reveals the backbone of a cascade connecting growth factor signaling with cell-cell adhesion during EMT.
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PMID:IGF-II induces rapid beta-catenin relocation to the nucleus during epithelium to mesenchyme transition. 1152 79

A cDNA encoding the porcine type 1 insulin-like growth factor receptor (IGF1R) was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR). The sequence of a 4.2-kb product was determined and had an open reading frame, encoding 1367 amino acids with 98.1 and 95.2% sequence similarity to the human and rat IGF1R, respectively. In the comparison of RT-PCR derived IGF1R sequences from 12 unrelated pigs, 12 silent sequence variants were found.
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PMID:Cloning of porcine IGF1 receptor cDNA and detection of sequence polymorphisms using RT-PCR. 1173 11

The retinoblastoma (Rb) tumor suppressor controls cellular proliferation, survival, and differentiation and is functionally inactivated by mutations or hyperphosphorylation in most human cancers. Although activation of endogenous Rb is thought to provide an effective approach to suppress cell proliferation, long-term inhibition of apoptosis by active Rb may have detrimental consequences in vivo. To directly test these paradigms, we targeted phosphorylation-resistant constitutively active Rb alleles, Rb Delta Ks, to the mouse mammary gland. Pubescent transgenic females displayed reduced ductal elongation and cell proliferation at the endbuds. Post-puberty transgenic mice exhibited precocious cellular differentiation and beta-casein expression and extended survival of the mammary epithelium with a moderate but specific effect on the expression of E2F1, IGF1R alpha, and phospho-protein kinase B/AKT. Remarkably, approximately 30% Rb Delta K transgenic females developed focal hyperplastic nodules, and approximately 7% exhibited full-blown mammary adenocarcinomas within 15 mo. Expression of the Rb Delta K transgene in these mammary tumors was reduced greatly. Our results suggest that transient activation of Rb induces cancer by extending cell survival and that the dual effects of Rb on cell proliferation and apoptosis impose an inherent caveat to the use of the Rb pathway for long-term cancer therapy.
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PMID:Activation of retinoblastoma protein in mammary gland leads to ductal growth suppression, precocious differentiation, and adenocarcinoma. 1177 37


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