Evidence for insulin-like growth factor (IGF)-independent transcriptional regulation of IGF binding protein-3 by growth hormone in SKHEP-1 human hepatocarcinoma cells.

Insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) is a polypeptide that forms a ternary complex with IGFs and an acid-labile subunit. The hormonal regulation of the components of this complex is highly controversial, and both IGF-I and GH have been shown to mediate the expression/synthesis of IGFBP-3. This study investigates the regulation of IGFBP-3 protein, measured by RIA and Western ligand blot, and messenger RNA (mRNA) expression, measured by Northern analysis and reverse transcriptase-PCR, in SKHEP-1 human hepatocarcinoma cells. SKHEP-1 cells significantly increased the IGFBP-3 concentrations in conditioned medium (CM) when treated with GH (0.1-10 ng/ml), IGF-I (1-100 ng/ml), or Des(1-3)-IGF-I (1-100 ng/ml) in a dose-dependent manner (>3-fold). The increase in IGFBP-3 protein concentrations in CM was accompanied by a corresponding increase in IGFBP-3 mRNA levels. Interestingly, time-course studies showed that the GH-induced increase in IGFBP-3 mRNA preceded the IGF-I-induced increase (6 h for GH-induced IGFBP-3 mRNA; 12 h for IGF-I-induced IGFBP-3 mRNA). The half-life of IGFBP-3 mRNA was evaluated after transcriptional arrest by treatment with a RNA polymerase II inhibitor (5,6-dichloro-1beta-D-ribofuranosylbenzimidazole), and was found to be 14-18 h and unaltered by GH or IGF-I treatment. The induction of IGFBP-3 by GH was not due to the indirect action of locally synthesized IGF-I, because 1) no immunoreactive IGF-I was detected in the CM of control or GH-treated cells; 2) Northern blots revealed no IGF-I mRNA expression in SKHEP-1 cells; 3) reverse transcriptase-PCR did not detect any expression of the IGF-I gene; and 4) time-course studies showed an earlier increase in IGFBP-3 mRNA after GH treatment than after IGF-I treatment. Thus, the results obtained in this study are consistent with an IGF-I-independent regulation of IGFBP-3 gene expression by GH.

[1]  Z. Gucev,et al.  Insulin-like growth factor-binding proteins (IGFBPs) and their regulatory dynamics. , 1996, The international journal of biochemistry & cell biology.

[2]  J. Guevara-Aguirre,et al.  A randomized, double blind, placebo-controlled trial on safety and efficacy of recombinant human insulin-like growth factor-I in children with growth hormone receptor deficiency. , 1995, The Journal of clinical endocrinology and metabolism.

[3]  P. Lehtovirta,et al.  Suppressed expression of insulin‐like growth factor binding protein‐1 mRNA in the endometrium: A molecular mechanism associating endometrial cancer with its risk factors , 1994, International journal of cancer.

[4]  P. Clayton,et al.  Growth hormone induces tyrosine phosphorylation but does not alter insulin-like growth factor-I gene expression in human IM9 lymphocytes. , 1994, Journal of molecular endocrinology.

[5]  E. Canalis,et al.  Complex pattern of insulin‐like growth factor binding protein expression in primary rat osteoblast enriched cultures: Regulation by prostaglandin E2, growth hormone, and the insulin‐like growth factors , 1994, Journal of cellular physiology.

[6]  J. Guevara-Aguirre,et al.  Growth hormone (GH) insensitivity due to primary GH receptor deficiency. , 1994, Endocrine reviews.

[7]  P. Tapanainen,et al.  Administration of growth hormone (GH), but not insulin-like growth factor-I (IGF-I), by continuous infusion can induce the formation of the 150-kilodalton IGF-binding protein-3 complex in GH-deficient rats. , 1994, Endocrinology.

[8]  Y. Oh,et al.  Insulin‐like growth factor binding proteins and their regulation , 1994, Acta paediatrica (Oslo, Norway : 1992). Supplement.

[9]  R. Baxter,et al.  The composition and distribution of insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) in the serum of growth hormone receptor-deficient patients: effects of IGF-I therapy on IGFBP-3. , 1993, The Journal of clinical endocrinology and metabolism.

[10]  C. Roberts,et al.  Growth hormone (GH) stimulates insulin-like growth factor-I (IGF-I) and IGF-I-binding protein-3, but not GH receptor gene expression in livers of juvenile rats. , 1993, Endocrinology.

[11]  J. Guevara-Aguirre,et al.  Hormonal and metabolic effects and pharmacokinetics of recombinant insulin-like growth factor-I in growth hormone receptor deficiency/Laron syndrome. , 1993, The Journal of clinical endocrinology and metabolism.

[12]  C. Conover,et al.  Posttranslational regulation of insulin-like growth factor binding protein-4 in normal and transformed human fibroblasts. Insulin-like growth factor dependence and biological studies. , 1993, The Journal of clinical investigation.

[13]  F. Pekonen,et al.  The expression of insulin-like growth factors and their binding proteins in normal human lymphocytes. , 1993, Acta endocrinologica.

[14]  A. Karasik,et al.  Long-term treatment of Laron type dwarfs with insulin-like growth factor-1 increases serum insulin-like growth factor-binding protein-3 in the absence of growth hormone activity. , 1993, Acta endocrinologica.

[15]  R. Baxter,et al.  Enhancement of the anabolic effects of growth hormone and insulin-like growth factor I by use of both agents simultaneously. , 1993, The Journal of clinical investigation.

[16]  Y. Hasegawa,et al.  Comparison between insulin-like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3) measurement in the diagnosis of growth hormone deficiency. , 1993, Endocrine journal.

[17]  L. Giudice,et al.  Measurement and characterization of insulin-like growth factor binding protein-3 in human biological fluids: discrepancies between radioimmunoassay and ligand blotting. , 1992, Endocrinology.

[18]  D. Clemmons,et al.  Identification of the forms of insulin-like growth factor-binding proteins produced by human fibroblasts and the mechanisms that regulate their secretion. , 1992, The Journal of biological chemistry.

[19]  M. Ranke,et al.  IGF binding protein 3 in patients with Laron type dwarfism: effect of exogenous rIGF‐I , 1992, Clinical endocrinology.

[20]  R. Hintz,et al.  Effects of continuous infusion of insulin-like growth factor I and II, alone and in combination with thyroxine or growth hormone, on the neonatal hypophysectomized rat. , 1992, Endocrinology.

[21]  A. Herington,et al.  Tissue distribution and regulation of insulin-like growth factor (IGF)-binding protein-3 messenger ribonucleic acid (mRNA) in the rat: comparison with IGF-I mRNA expression. , 1992, Endocrinology.

[22]  D. Clemmons,et al.  Regulation of insulin-like growth factor (IGF) binding proteins in transgenic mice with altered expression of growth hormone and IGF-I. , 1991, Endocrinology.

[23]  L. Giudice,et al.  A simple assay for proteolysis of IGFBP-3. , 1991, The Journal of clinical endocrinology and metabolism.

[24]  A. Hoffman,et al.  Differential effects of insulin-like growth factor (IGF)-I and IGF-II on the expression of IGF binding proteins (IGFBPs) in a rat neuroblastoma cell line: isolation and characterization of two forms of IGFBP-4. , 1991, Endocrinology.

[25]  B. Posner,et al.  The differential regulation by glucagon and growth hormone of insulin-like growth factor (IGF)-I and IGF binding proteins in cultured rat hepatocytes. , 1991, Endocrinology.

[26]  A. N. Corps,et al.  Mitogens regulate the production of insulin-like growth factor-binding protein by Swiss 3T3 cells. , 1991, Endocrinology.

[27]  C. Conover,et al.  Structural and biological characterization of bovine insulin-like growth factor binding protein-3. , 1990, Endocrinology.

[28]  J. Wallace,et al.  Insulin-like growth factor-I (IGF-I) and IGF-binding proteins both decline in the rat during late pregnancy. , 1990, The Journal of endocrinology.

[29]  M. Binoux,et al.  Regulation of binding proteins for insulin-like growth factors (IGF) in humans. Increased expression of IGF binding protein 2 during IGF I treatment of healthy adults and in patients with extrapancreatic tumor hypoglycemia. , 1990, The Journal of clinical investigation.

[30]  G. Rodan,et al.  Increased activity of insulin-like growth factor (IGF) in osteoblastic cells in the presence of growth hormone (GH): positive correlation with the presence of the GH-induced IGF-binding protein BP-3. , 1990, Endocrinology.

[31]  H. Zeisel,et al.  A specific radioimmunoassay for the growth hormone (GH)-dependent somatomedin-binding protein: its use for diagnosis of GH deficiency. , 1990, The Journal of clinical endocrinology and metabolism.

[32]  M. Rechler,et al.  Tissue, developmental, and metabolic regulation of messenger ribonucleic acid encoding a rat insulin-like growth factor-binding protein. , 1990, Endocrinology.

[33]  D. Clemmons,et al.  Insulin-like growth factor-I (IGF-I) infusion into hypophysectomized or protein-deprived rats induces specific IGF-binding proteins in serum. , 1989, Endocrinology.

[34]  Y. Le Bouc,et al.  Molecular forms of serum insulin-like growth factor (IGF)-binding proteins in man: relationships with growth hormone and IGFs and physiological significance. , 1989, The Journal of clinical endocrinology and metabolism.

[35]  E. Froesch,et al.  Recombinant human insulin-like growth factor I induces its own specific carrier protein in hypophysectomized and diabetic rats. , 1989, Proceedings of the National Academy of Sciences of the United States of America.

[36]  E. Froesch,et al.  Release of insulin-like growth factor carrier proteins by osteoblasts: stimulation by estradiol and growth hormone. , 1989, Biochemical and biophysical research communications.

[37]  C. Conover,et al.  Insulin-like growth factor binding proteins from cultured human fibroblasts. Characterization and hormonal regulation. , 1989, The Journal of clinical investigation.

[38]  E. Froesch,et al.  Production of carrier proteins for insulin‐like growth factors (IGFs) by rat osteoblastic cells Regulation by IGF I and cortisol , 1989, FEBS letters.

[39]  W. Wood,et al.  Cloning and expression of the growth hormone-dependent insulin-like growth factor-binding protein. , 1988, Molecular endocrinology.

[40]  R. Baxter,et al.  Insulin-like growth factor-binding proteins (IGF-BPs) produced by human skin fibroblasts: immunological relationship to other human IGF-BPs. , 1988, Endocrinology.

[41]  R. Baxter,et al.  Radioimmunoassay of growth hormone-dependent insulinlike growth factor binding protein in human plasma. , 1986, The Journal of clinical investigation.

[42]  D. Powell,et al.  Serum somatomedin levels in adults with chronic renal failure: the importance of measuring insulin-like growth factor I (IGF-I) and IGF-II in acid-chromatographed uremic serum. , 1986, The Journal of clinical endocrinology and metabolism.

[43]  M. Binoux,et al.  Analysis of serum insulin-like growth factor binding proteins using western blotting: use of the method for titration of the binding proteins and competitive binding studies. , 1986, Analytical biochemistry.

[44]  A. Ullrich,et al.  Insulin-like growth factor II precursor gene organization in relation to insulin gene family , 1984, Nature.

[45]  R. Weinmann,et al.  Mechanism of action of DRB. III. Effect on specific in vitro initiation of transcription. , 1983, Journal of molecular biology.

[46]  J. Martial,et al.  A method for isolation of intact, translationally active ribonucleic acid. , 1983, DNA.