1
|
Role of Alternatively Spliced Messenger RNA (mRNA) Isoforms of the Insulin-Like Growth Factor 1 (IGF1) in Selected Human Tumors. Int J Mol Sci 2020; 21:ijms21196995. [PMID: 32977489 PMCID: PMC7582825 DOI: 10.3390/ijms21196995] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023] Open
Abstract
Insulin-like growth factor 1 (IGF1) is a key regulator of tissue growth and development that is also implicated in the initiation and progression of various cancers. The human IGF1 gene contains six exons and five long introns, the transcription of which is controlled by two promoters (P1 and P2). Alternate promoter usage, as well as alternative splicing (AS) of IGF1, results in the expression of six various variants (isoforms) of mRNA, i.e., IA, IB, IC, IIA, IIB, and IIC. A mature 70-kDa IGF1 protein is coded only by exons 3 and 4, while exons 5 and 6 are alternatively spliced code for the three C-terminal E peptides: Ea (exon 6), Eb (exon 5), and Ec (fragments of exons 5 and 6). The most abundant of those transcripts is IGF1Ea, followed by IGF1Eb and IGF1Ec (also known as mechano-growth factor, MGF). The presence of different IGF1 transcripts suggests tissue-specific auto- and/or paracrine action, as well as separate regulation of both of these gene promoters. In physiology, the role of different IGF1 mRNA isoforms and pro-peptides is best recognized in skeletal muscle tissue. Their functions include the development and regeneration of muscles, as well as maintenance of proper muscle mass. In turn, in nervous tissue, a neuroprotective function of short peptides, produced as a result of IGF1 expression and characterized by significant blood-brain barrier penetrance, has been described and could be a potential therapeutic target. When it comes to the regulation of carcinogenesis, the potential biological role of different var iants of IGF1 mRNAs and pro-peptides is also intensively studied. This review highlights the role of IGF1 isoform expression (mRNAs, proteins) in physiology and different types of human tumors (e.g., breast cancer, cervical cancer, colorectal cancer, osteosarcoma, prostate and thyroid cancers), as well as mechanisms of IGF1 spliced variants involvement in tumor biology.
Collapse
|
2
|
Hobeika E, Armouti M, Fierro MA, Winston N, Scoccia H, Zamah AM, Stocco C. Regulation of Insulin-Like Growth Factor 2 by Oocyte-Secreted Factors in Primary Human Granulosa Cells. J Clin Endocrinol Metab 2020; 105:5582040. [PMID: 31588501 PMCID: PMC6938692 DOI: 10.1210/clinem/dgz057] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 09/20/2019] [Indexed: 01/02/2023]
Abstract
CONTEXT Human granulosa cells (hGCs) produce and respond to insulin-like growth factor 2 (IGF2) but whether the oocyte participates in IGF2 regulation in humans is unknown. OBJECTIVE To determine the role of oocyte-secreted factors (OSFs) such as growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) in IGF2 production by hGCs. DESIGN Primary human cumulus GCs in culture. SETTING University infertility center. PATIENTS OR OTHER PARTICIPANTS GCs of women undergoing in vitro fertilization. INTERVENTION(S) Cells treated with GDF9 and BMP15 in the presence of vehicle, follicle-stimulating hormone (FSH), dibutyryl cyclic-AMP (dbcAMP), or mothers against decapentaplegic homolog (SMAD) inhibitors. MAIN OUTCOME MEASURE(S) Quantification of mRNA, protein, promoter activity, and DNA methylation. RESULTS FSH stimulation of IGF2 (protein and mRNA) was significantly potentiated by the GDF9 and BMP15 (G+B) combination (P < 0.0001) in a concentration-dependent manner showing a maximal effect at 5 ng/mL each. However, GDF9 or BMP15 alone or in combination (G+B) have no effect on IGF2 in the absence of FSH. FSH stimulated IGF2 promoter 3 activity, but G+B had no effect on promoter activity. G+B potentiated IGF2 stimulation by cAMP. SMAD3 inhibitors inhibited G+B enhancement of IGF2 stimulation by FSH (P < 0.05) but had no effect on FSH induction. Moreover, inhibition of insulin-like growth factor receptor partially blocked G+B potentiation of FSH actions (P < 0.009). CONCLUSIONS For the first time, we show that the oocyte actively participates in the regulation of IGF2 expression in hGCs, an effect that is mediated by the specific combination of G+B via SMAD2/3, which in turn target mechanisms downstream of the FSH receptor.
Collapse
Affiliation(s)
- Elie Hobeika
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Illinois at Chicago College of Medicine, Chicago, Illinois
| | - Marah Armouti
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Michele A Fierro
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Illinois at Chicago College of Medicine, Chicago, Illinois
| | - Nichola Winston
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Illinois at Chicago College of Medicine, Chicago, Illinois
| | - Humberto Scoccia
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Illinois at Chicago College of Medicine, Chicago, Illinois
| | - Alberuni M Zamah
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, the University of Chicago Medicine, Chicago, Illinois
| | - Carlos Stocco
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
- Correspondence: Carlos Stocco, 835 S Wolcott Ave, Chicago, Illinois, 60612. E-mail:
| |
Collapse
|
3
|
Rotwein P. Characterizing the complexity of Australian marsupial insulin-like growth factor 1 genes. Mol Cell Endocrinol 2019; 488:52-69. [PMID: 30871962 PMCID: PMC6996716 DOI: 10.1016/j.mce.2019.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 01/15/2023]
Abstract
Insulin-like growth factor 1 (IGF1) actions are essential for somatic growth and tissue repair. IGF1 gene regulation is controlled by many inputs, with growth hormone playing a major role. In most mammals, the 6-exon IGF1/Igf1 gene produces multiple transcripts via independent activity of its promoters plus alternative RNA splicing and differential polyadenylation. Here, by analyzing public genomic and RNA-sequencing repositories, I have characterized three Australian marsupial IGF1 genes. Koala, Tasmanian devil, and wallaby IGF1 are more complicated than other mammals, as they contain up to 11 exons, and encode multiple mRNAs and predicted protein precursors, including potentially novel isoforms. Moreover, just two of multiple growth hormone-stimulated transcriptional enhancers found in other IGF1/Igf1 loci are detected in these species. These observations define Australian marsupial IGF1 genes and demonstrate that comprehensive interrogation of genomic and RNA-sequencing resources is an effective strategy for characterizing genes and gene expression in otherwise experimentally intractable organisms.
Collapse
Affiliation(s)
- Peter Rotwein
- Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech Health University Health Sciences Center, El Paso, TX 79905, USA
| |
Collapse
|
4
|
Rotwein P. Insulinlike Growth Factor 1 Gene Variation in Vertebrates. Endocrinology 2018; 159:2288-2305. [PMID: 29697760 PMCID: PMC6692883 DOI: 10.1210/en.2018-00259] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 04/19/2018] [Indexed: 12/31/2022]
Abstract
IGF1-a small, single-chain, secreted peptide in mammals-is essential for normal somatic growth and is involved in a variety of other physiological and pathophysiological processes. IGF1 expression appears to be controlled by several different signaling mechanisms in mammals, with GH playing a key role by activating an inducible transcriptional pathway via the Jak2 protein kinase and the Stat5b transcription factor. Here, to understand aspects of Igf1 gene regulation over a substantially longer timeline than is discernible in mammals, Igf1 genes have been examined in 21 different nonmammalian vertebrates representing five different classes and ranging over ∼500 million years of evolutionary history. Parts of vertebrate Igf1 genes resemble components found in mammals. Conserved exons encoding the mature IGF1 protein are detected in all 21 species studied and are separated by a large intron, as seen in mammals; the single promoter contains putative regulatory elements that are similar to those functionally mapped in human IGF1 promoter 1. In contrast, GH-activated Stat5b-binding enhancers found in mammalian IGF1 loci are completely absent, there is no homolog of promoter 2 or exon 2 in any nonmammalian vertebrate, and different types of "extra" exons not present in mammals are found in birds, reptiles, and teleosts. These data collectively define properties of Igf1 genes and IGF1 proteins that were likely present in the earliest vertebrates and support the contention that common structural and regulatory features in Igf1 genes have a long evolutionary history.
Collapse
Affiliation(s)
- Peter Rotwein
- Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas
- Correspondence: Peter Rotwein, MD, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, Texas 79905. E-mail:
| |
Collapse
|
5
|
Rotwein P. Diversification of the insulin-like growth factor 1 gene in mammals. PLoS One 2017; 12:e0189642. [PMID: 29240807 PMCID: PMC5730178 DOI: 10.1371/journal.pone.0189642] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 11/29/2017] [Indexed: 12/12/2022] Open
Abstract
Insulin-like growth factor 1 (IGF1), a small, secreted peptide growth factor, is involved in a variety of physiological and patho-physiological processes, including somatic growth, tissue repair, and metabolism of carbohydrates, proteins, and lipids. IGF1 gene expression appears to be controlled by several different signaling cascades in the few species in which it has been evaluated, with growth hormone playing a major role by activating a pathway involving the Stat5b transcription factor. Here, genes encoding IGF1 have been evaluated in 25 different mammalian species representing 15 different orders and ranging over ~180 million years of evolutionary diversification. Parts of the IGF1 gene have been fairly well conserved. Like rat Igf1 and human IGF1, 21 of 23 other genes are composed of 6 exons and 5 introns, and all 23 also contain recognizable tandem promoters, each with a unique leader exon. Exon and intron lengths are similar in most species, and DNA sequence conservation is moderately high in orthologous exons and proximal promoter regions. In contrast, putative growth hormone-activated Stat5b-binding enhancers found in analogous locations in rodent Igf1 and in human IGF1 loci, have undergone substantial variation in other mammals, and a processed retro-transposed IGF1 pseudogene is found in the sloth locus, but not in other mammalian genomes. Taken together, the fairly high level of organizational and nucleotide sequence similarity in the IGF1 gene among these 25 species supports the contention that some common regulatory pathways had existed prior to the beginning of mammalian speciation.
Collapse
Affiliation(s)
- Peter Rotwein
- Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America
- * E-mail:
| |
Collapse
|
6
|
Rotwein P. Variation in the Insulin-Like Growth Factor 1 Gene in Primates. Endocrinology 2017; 158:804-814. [PMID: 28324014 PMCID: PMC5460808 DOI: 10.1210/en.2016-1920] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 01/13/2017] [Indexed: 12/21/2022]
Abstract
Insulin-like growth factor 1 (IGF1) is a multifunctional peptide that is involved in a wide range of physiological and pathophysiological processes in many animal species, ranging from somatic growth in children to metabolism and tissue regeneration and repair in adults. The IGF1 gene is under multifactorial regulation in the few species in which it has been studied, with major control being exerted by growth hormone through a gene expression pathway involving inducible binding of the STAT5b transcription factor to dispersed enhancer elements. In this study, using resources available in public genomic databases, genes encoding IGF1 have been analyzed in a cohort of six nonhuman primate species representing >60 million years of evolutionary diversification from a common ancestor: chimpanzee, gorilla, macaque, olive baboon, marmoset, and mouse lemur. The IGF1 gene has been well conserved among these primates. Similar to human IGF1, each gene appears to be composed of six exons and five introns, and contains recognizable tandem promoters, each with a unique leader exon. Exon and intron lengths are very similar, and DNA sequence conservation is high, not only in orthologous exons and promoter regions, but also in putative growth hormone-activated STAT5b-binding enhancers that are found in analogous locations in IGF1 intron 3 and in 5' distal intergenic DNA. Taken together, the high level of organizational and nucleotide sequence similarity in the IGF1 gene and locus among these seven species supports the contention that common regulatory paradigms had existed prior to the onset of primate speciation >85 million years ago.
Collapse
Affiliation(s)
- Peter Rotwein
- Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech Health University Health Sciences Center, El Paso, Texas 79905
| |
Collapse
|
7
|
Mukherjee A, Alzhanov D, Rotwein P. Defining human insulin-like growth factor I gene regulation. Am J Physiol Endocrinol Metab 2016; 311:E519-29. [PMID: 27406741 PMCID: PMC5005972 DOI: 10.1152/ajpendo.00212.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/08/2016] [Indexed: 11/22/2022]
Abstract
Growth hormone (GH) plays an essential role in controlling somatic growth and in regulating multiple physiological processes in humans and other species. Insulin-like growth factor I (IGF-I), a conserved, secreted 70-amino acid peptide, is a critical mediator of many of the biological effects of GH. Previous studies have demonstrated that GH rapidly and potently promotes IGF-I gene expression in rodents and in some other mammals through the transcription factor STAT5b, leading to accumulation of IGF-I mRNAs and production of IGF-I. Despite this progress, very little is known about how GH or other trophic factors control human IGF1 gene expression, in large part because of the absence of any cellular model systems that robustly express IGF-I. Here, we have addressed mechanisms of regulation of human IGF-I by GH after generating cells in which the IGF1 chromosomal locus has been incorporated into a mouse cell line. Using this model, we found that physiological levels of GH rapidly stimulate human IGF1 gene transcription and identify several potential transcriptional enhancers in chromatin that bind STAT5b in a GH-regulated way. Each of the putative enhancers also activates a human IGF1 gene promoter in reconstitution experiments in the presence of the GH receptor, STAT5b, and GH. Thus we have developed a novel experimental platform that now may be used to determine how human IGF1 gene expression is controlled under different physiological and pathological conditions.
Collapse
Affiliation(s)
- Aditi Mukherjee
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon; and
| | - Damir Alzhanov
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon; and
| | - Peter Rotwein
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon; and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech Health University Health Sciences Center, El Paso, Texas
| |
Collapse
|
8
|
Baumgarten SC, Convissar SM, Zamah AM, Fierro MA, Winston NJ, Scoccia B, Stocco C. FSH Regulates IGF-2 Expression in Human Granulosa Cells in an AKT-Dependent Manner. J Clin Endocrinol Metab 2015; 100:E1046-55. [PMID: 26066673 PMCID: PMC4524996 DOI: 10.1210/jc.2015-1504] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT IGF-2 is highly expressed in the granulosa cells of human dominant ovarian follicles; however, little is known about the regulation of the IGF-2 gene or the interaction of IGF-2 and FSH during follicle development. OBJECTIVE To examine the mechanisms involved in the regulation of the IGF-2 gene by FSH and the interplay between FSH and IGF-2 during granulosa cell differentiation. Design, Setting, Patients, and Interventions: Cumulus granulosa cells were separated from cumulus-oocyte complexes isolated from the follicular aspirates of in vitro fertilization patients and cultured for in vitro studies. MAIN OUTCOME Protein and mRNA levels of IGF-2 and CYP19A1 (aromatase) were quantified using Western blot and quantitative real-time PCR. IGF-2 promoter-specific activation was determined by the amplification of alternative exons by PCR. Cell proliferation was assessed after treatment with FSH and/or IGF-2. RESULTS FSH significantly enhanced IGF-2 expression after 8 hours of treatment and at low doses (1 ng/mL). Reciprocally, IGF-2 synergized with FSH to increase cell proliferation and the expression of CYP19A1. When IGF-2 activity was blocked, FSH was no longer able to stimulate CYP19A1 expression. Determination of IGF-2 promoter usage in human cumulus cells showed that the IGF-2 gene is driven by promoters P3 and P4. However, FSH exclusively increased P3 promoter-derived transcripts. Moreover, the FSH-induced stimulation of P3-driven IGF-2 transcripts was blocked by cotreatment with inhibitors of AKT or IGF-1 receptor (IGF-1R). The inhibitory effect of the IGF-1R inhibitor on FSH-induced IGF-2 mRNA accumulation was reversed by overexpression of a constitutively active AKT construct. CONCLUSIONS FSH is a potent enhancer of IGF-2 expression in human granulosa cells. In return, IGF-2 activation of the IGF-1R and AKT is required for FSH to stimulate CYP19A1 expression and proliferation of granulosa cells. These findings suggest a positive loop interaction between FSH and IGF-2 that is critical for human granulosa cell proliferation and differentiation.
Collapse
Affiliation(s)
- Sarah C Baumgarten
- Department of Physiology and Biophysics (S.C.B., S.M.C., C.S.), and Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology (A.M.Z., M.A.F., N.J.W., B.S.), University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612
| | - Scott M Convissar
- Department of Physiology and Biophysics (S.C.B., S.M.C., C.S.), and Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology (A.M.Z., M.A.F., N.J.W., B.S.), University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612
| | - A Musa Zamah
- Department of Physiology and Biophysics (S.C.B., S.M.C., C.S.), and Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology (A.M.Z., M.A.F., N.J.W., B.S.), University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612
| | - Michelle A Fierro
- Department of Physiology and Biophysics (S.C.B., S.M.C., C.S.), and Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology (A.M.Z., M.A.F., N.J.W., B.S.), University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612
| | - Nicola J Winston
- Department of Physiology and Biophysics (S.C.B., S.M.C., C.S.), and Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology (A.M.Z., M.A.F., N.J.W., B.S.), University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612
| | - Bert Scoccia
- Department of Physiology and Biophysics (S.C.B., S.M.C., C.S.), and Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology (A.M.Z., M.A.F., N.J.W., B.S.), University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612
| | - Carlos Stocco
- Department of Physiology and Biophysics (S.C.B., S.M.C., C.S.), and Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology (A.M.Z., M.A.F., N.J.W., B.S.), University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612
| |
Collapse
|
9
|
PELLEGRINI M, ARGIBAY P, GOMEZ D. Dietary factors, genetic and epigenetic influences in colorectal cancer. Exp Ther Med 2010; 1:241-250. [PMID: 22993535 PMCID: PMC3445943 DOI: 10.3892/etm_00000038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Accepted: 11/10/2009] [Indexed: 01/05/2023] Open
Abstract
Genetic influences, together with epigenetic components and dietary factors, play a fundamental role in the initiation and progression of cancer by causing a number of deregulations. Colorectal cancer (CRC) is a disease influenced by dietary factors, for which established genetic and epigenetic alterations have been identified. Within CRC, there are hereditary syndromes that present mutations in the germ-line hMLH1, and also alterations in the methylation of the promoters. Epigenetics has also been established as a pathway of carcinogenesis. In the present review, we analyzed studies conducted to discern the different pathways leading to established CRC, stressing the importance of identifying factors that may predict CRC at an early stage, since it is mostly a silent disease observed at the clinical level in advanced stages.
Collapse
Affiliation(s)
- M.L. PELLEGRINI
- Instituto de Ciencias Básicas y Medicina Experimental, Hospital Italiano de Buenos Aires
| | - P. ARGIBAY
- Instituto de Ciencias Básicas y Medicina Experimental, Hospital Italiano de Buenos Aires
| | - D.E. GOMEZ
- Laboratorio de Oncología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Buenos Aires,
Argentina
| |
Collapse
|
10
|
Breuhahn K, Longerich T, Schirmacher P. Dysregulation of growth factor signaling in human hepatocellular carcinoma. Oncogene 2006; 25:3787-800. [PMID: 16799620 DOI: 10.1038/sj.onc.1209556] [Citation(s) in RCA: 432] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Dysregulation of pleiotropic growth factors, receptors and their downstream signaling pathway components represent a central protumorigenic principle in human hepatocarcinogenesis. Especially the Insulin-like Growth Factor/IGF-1 receptor (IGF/IGF-1R), Hepatocyte Growth Factor (HGF/MET), Wingless (Wnt/beta-catenin/FZD), Transforming Growth Factor alpha/Epidermal Growth Factor receptor (TGFalpha/EGFR) and Transforming Growth Factor beta (TGFbeta/TbetaR) pathways contribute to proliferation, antiapoptosis and invasive behavior of tumor cells. This review focuses on the relevant alterations in these pathways identified in human human hepatocellular carcinomas (HCCs). Resultant functional effects are modulated by multiple cross-talks between the different signaling pathways and additional tumor-relevant factors, such as cyclooxygenase-2 and p53. Several specific strategies are currently under development such as receptor kinase inhibitors, neutralizing antibodies and antagonistic proteins, which may improve the systemic treatment of human HCCs.
Collapse
Affiliation(s)
- K Breuhahn
- Institute of Pathology, University of Heidelberg, Heidelberg, Germany
| | | | | |
Collapse
|
11
|
Miyamoto S, Nakamura M, Shitara K, Nakamura K, Ohki Y, Ishii G, Goya M, Kodama K, Sangai T, Maeda H, Shi-Chuang Z, Chiba T, Ochiai A. Blockade of Paracrine Supply of Insulin-Like Growth Factors Using Neutralizing Antibodies Suppresses the Liver Metastasis of Human Colorectal Cancers. Clin Cancer Res 2005; 11:3494-502. [PMID: 15867252 DOI: 10.1158/1078-0432.ccr-04-1701] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Environmental stimuli, such as organ-specific growth factors, can influence the metastatic potential of a tumor. The liver is the main source of insulin-like growth factors (IGFs). The importance of IGF signal in hepatic metastasis has been clarified mainly by IGF-I receptor targeting strategies. This study aims to confirm these precedent reports by novel tool, neutralizing antibodies against IGFs and to show that IGFs are promising therapeutic targets for hepatic metastasis in vivo. Hepatic metastasis was induced by intrasplenic injection of human colorectal cancer cell line, HT29. The antimetastatic effects of three antibodies (anti-mouse IGF-I, anti-mouse IGF-II, and anti-human/mouse IGF-II designated KM1468) were tested singly or in combination in the early phase of metastasis. The dose escalation effect of KM1468 and its survival benefit were examined in the early and late phases of metastasis. The mechanism of IGF neutralization was investigated with immunohistochemistry. Dual neutralization of paracrine IGF-I and IGF-II showed modest additive antimetastatic effects than single neutralization of IGF-I or IGF-II. In any phase of metastasis, neutralization led to significant tumor growth inhibition and longer survival. Dose escalation of KM1468 influenced survival only in the late phase of metastasis. Apoptosis increased significantly in the antibody-treated group compared with the control group (P = 0.0025) In conclusion, IGFs are promising therapeutic targets for hepatic metastases of colorectal cancers. However, the IGF dependency is probably variable in the metastatic process.
Collapse
Affiliation(s)
- Shin'ichi Miyamoto
- Pathology Division, National Cancer Center Research Institute East, Chiba, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
van Doorn J, Hoogerbrugge CM, Koster JG, Bloemen RJ, Hoekman K, Mudde AH, van Buul-Offers SC. Antibodies Directed against the E Region of Pro-Insulin-like Growth Factor-II Used to Evaluate Non-Islet Cell Tumor-induced Hypoglycemia. Clin Chem 2002. [DOI: 10.1093/clinchem/48.10.1739] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
AbstractBackground: Detection of incompletely processed precursor forms of insulin-like growth factor-II (“big” IGF-II) in plasma is essential for both the diagnosis and follow-up of non-islet cell tumor-induced hypoglycemia (NICTH) and may be relevant to other diseases as well. RIA using an antibody raised against a synthetic peptide consisting of the first 21 amino acids of the E domain [E(68–88)] of human pro-IGF-II cannot distinguish between E-peptide-containing big IGF-II and cleaved E domain or fragments. We therefore developed and validated an ELISA that specifically detects big IGF-II in plasma.Methods: The ELISA used a solid-phase antibody to E(68–88) and a liquid-phase monoclonal hIGF-II antibody. Pro-IGF-II purified from normal human plasma was used as a calibrator. Acid Sep-Pak C18 extracts of plasma from NICTH patients were analyzed, and the results were compared with those obtained for plasma samples from healthy individuals. In addition, blood specimens derived from dialyzed patients with chronic renal failure, which contained relatively high concentrations of cleaved E domain or fragments, were studied. The results were validated by acid Sephadex G-50 gel filtration.Results: Results from this ELISA indicated that the concentration of big IGF-II in NICTH plasma was higher (mean ± SD, 22.6 ± 9.4 nmol/L) than in normal plasma (3.8 nmol/L). Conversely, the concentrations in pooled CRF plasma (2.0 ± 0.8 nmol/L) were low. Antibodies directed against either E(68–88) or E(13–134) of pro-IGF-II could be used to detect these peptides in tumor tissue by immunohistochemistry.Conclusions: The possibility of quantifying pro-IGF-II by ELISA in plasma represents a potentially useful tool for the diagnosis and follow-up of NICTH and should facilitate further in vitro and in vivo studies on its regulation and function in humans.
Collapse
Affiliation(s)
- Jaap van Doorn
- Department of Pediatrics, Laboratory of Endocrinology, Wilhelmina Children’s Hospital/University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands
| | - Cok M Hoogerbrugge
- Department of Pediatrics, Laboratory of Endocrinology, Wilhelmina Children’s Hospital/University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands
| | - Johanna G Koster
- Department of Pediatrics, Laboratory of Endocrinology, Wilhelmina Children’s Hospital/University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands
| | - Ruud J Bloemen
- Department of Pediatrics, Laboratory of Endocrinology, Wilhelmina Children’s Hospital/University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands
| | - Klaas Hoekman
- Department of Medical Oncology, Free University Medical Center, 1007 MB Amsterdam, The Netherlands
| | - Aart H Mudde
- Slingeland Hospital, 7000 AD Doetinchem, The Netherlands
| | - Sylvia C van Buul-Offers
- Department of Pediatrics, Laboratory of Endocrinology, Wilhelmina Children’s Hospital/University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands
| |
Collapse
|
13
|
Wu HK, Squire JA, Song Q, Weksberg R. Promoter-dependent tissue-specific expressive nature of imprinting gene, insulin-like growth factor II, in human tissues. Biochem Biophys Res Commun 1997; 233:221-6. [PMID: 9144427 DOI: 10.1006/bbrc.1997.6431] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The insulin-like growth factor II (IGF2) is a polypeptide with structure homology to insulin which possesses mitogen activity, and imprinted with paternal allele. In order to elucidate the distribution of imprinting pattern and relationship between allele- and tissue-specific expression of IGF2 in growth and maturation of human tissues, we investigated allele-specific expression of IGF2 in a wide spectrum of normal maturated human tissues by a PCR-based assay and found monoallelic expression in all eight-type tissues tested except human adult liver. Moreover, when a RT-PCR based sensitive allele-specific primer extension for an Apa I polymorphism within exon 9 of IGF2 was used, the analysis revealed the gene was normally imprinted in placenta; in contrast to the finding with placenta, IGF2 transcripts were biallelically expressed in human adult liver. Our results have clearly demonstrated preferential paternal expression and tissue-specific imprinting pattern of IGF2 in all human tissues tested in this study. Collectively, since IGF2 expression in developing fetal and adult liver is specified by distinct promoters, these extensive observations definitively indicate that transcriptional imprinting of IGF2 is more likely a promoter dependent manner.
Collapse
Affiliation(s)
- H K Wu
- Department of Molecular Pathology, The Hospital for Sick Children, Faculty of Medicine, University of Toronto, Ontario, Canada
| | | | | | | |
Collapse
|
14
|
Reiss K, Cheng W, Ferber A, Kajstura J, Li P, Li B, Olivetti G, Homcy CJ, Baserga R, Anversa P. Overexpression of insulin-like growth factor-1 in the heart is coupled with myocyte proliferation in transgenic mice. Proc Natl Acad Sci U S A 1996; 93:8630-5. [PMID: 8710922 PMCID: PMC38724 DOI: 10.1073/pnas.93.16.8630] [Citation(s) in RCA: 219] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Transgenic mice were generated in which the cDNA for the human insulin-like growth factor 1B (IGF-1B) was placed under the control of a rat alpha-myosin heavy chain promoter. In mice heterozygous for the transgene, IGF-1B mRNA was not detectable in the fetal heart at the end of gestation, was present in modest levels at 1 day after birth, and increased progressively with postnatal maturation, reaching a peak at 75 days. Myocytes isolated from transgenic mice secreted 1.15 +/- 0.25 ng of IGF-1 per 10(6) cells per 24 hr versus 0.27 +/- 0.10 ng in myocytes from homozygous wild-type littermates. The plasma level of IGF-1 increased 84% in transgenic mice. Heart weight was comparable in wild-type littermates and transgenic mice up to 45 days of age, but a 42%, 45%, 62%, and 51% increase was found at 75, 135, 210, and 300 days, respectively, after birth. At 45, 75, and 210 days, the number of myocytes in the heart was 21%, 31%, and 55% higher, respectively, in transgenic animals. In contrast, myocyte cell volume was comparable in transgenic and control mice at all ages. In conclusion, overexpression of IGF-1 in myocytes leads to cardiomegaly mediated by an increased number of cells in the heart.
Collapse
Affiliation(s)
- K Reiss
- Department of Medicine, New York Medical College, Valhalla 10595, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Ekström TJ, Cui H, Nyström A, Rutanen EM, Ohlsson R. Monoallelic expression of IGF2 at the human fetal/maternal boundary. Mol Reprod Dev 1995; 41:177-83. [PMID: 7654371 DOI: 10.1002/mrd.1080410208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
IGF2 is expressed in both placental and decidual tissues, enabling an analysis of the parental imprinting over the fetomaternal boundary. Evidence is provided that IGF2 is monoallelically expressed in both placenta and pregnant, as well as nonpregnant, endometrium. These observations suggest that the maternally derived IGF2 allele is inactivated during germline transmission. Comparison of promoter usage in decidua and placental samples shows that the P3 promoter appears to regulated independently of the others. These observations are discussed with respect to current models of IGF2 imprinting and the hypothesized conflict of parental reproductive interests which bears on the phenomenon of parental imprinting.
Collapse
Affiliation(s)
- T J Ekström
- Department of Clinical Neuroscience, Karolinska Hospital, Stockholm, Sweden
| | | | | | | | | |
Collapse
|
16
|
Ekström TJ, Cui H, Li X, Ohlsson R. Promoter-specific IGF2 imprinting status and its plasticity during human liver development. Development 1995; 121:309-16. [PMID: 7768174 DOI: 10.1242/dev.121.2.309] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
IGF2 has been shown to be expressed preferentially from the paternally derived allele, although the maternal allele can be found active during both prenatal and postnatal development as well as in neoplastic tumours in humans. We addressed here whether or not the biallelic expression patterns that can be seen during postnatal human liver development reflected a coordinated change in the activities of the four promoters of human IGF2. We show here that the P2, P3 and P4 promoters, but not the P1 promoter, display monoallelic activity in embryonic, neonatal and younger infant liver specimens. The P2, P3 and P4 promoters can, however, be found active either monoallelically or biallelically or even monoallelically on opposite parental alleles in older infant and adult liver specimens. In contrast, H19, which is closely linked to IGF2, is monoallelically expressed in all postnatal liver samples analysed. We conclude that the functional imprinting status of IGF2 during postnatal liver development appears to be promoter/enhancer-specific and either partly or completely independent of H19.
Collapse
Affiliation(s)
- T J Ekström
- Department of Clinical Neuroscience, Karolinska Hospital, Stockholm, Sweden
| | | | | | | |
Collapse
|
17
|
Rivkin M, Rosen KM, Villa-Komaroff L. Identification of an antisense transcript from the IGF-II locus in mouse. Mol Reprod Dev 1993; 35:394-7. [PMID: 8398118 DOI: 10.1002/mrd.1080350413] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We have identified a novel antisense RNA transcribed from the insulin-like growth factor-II (IGF-II) locus in mouse. This transcript was identified using probes derived from cloned genomic DNA lying between the insulin II locus and the IGF-II locus. S1 protection assays confirmed that this transcript is transcribed from the strand complementary to the stand encoding IGF-II. A 3.75 kb RNA was consistently detected on northern analysis of mouse tissue using different randomly primed DNA probes generated from this region. S1 nuclease protection analysis identified three exons contained in the transcript. Developmental northern analysis was performed using RNA from embryonic (E) and postnatal (P) tissues of E10, E13, E18, P1, P4, P10, and adult mice. The antisense RNA was most abundant in E13 and E18 mouse and was present in greatest amounts in skull, skeletal muscle, cardiac muscle, and placenta. No signal for this RNA was detected after the fourth day of life in any tissue studied.
Collapse
Affiliation(s)
- M Rivkin
- Department of Neurology, Harvard Medical School, Boston, Massachusetts 02115
| | | | | |
Collapse
|