Insulin upregulates the expression of zinc finger and BTB domain-containing 7A in HepG2 cells

Tian,Jing; Jiang,Yuyang

doi:10.3892/mmr.2012.1113

Insulin upregulates the expression of zinc finger and BTB domain-containing 7A in HepG2 cells

Authors:
- Jing Tian
- Yuyang Jiang
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Affiliations: School of Life Sciences, Tsinghua University, Beijing 100084, P.R. China, The Ministry-Province Jointly Constructed Base for State Key Laboratory, Shenzhen Key Laboratory of Chemical Biology, the Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, P.R. China
Published online on: October 1, 2012 https://doi.org/10.3892/mmr.2012.1113
Pages: 1379-1384

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Abstract

Zinc finger and BTB domain-containing 7A (Zbtb7A) is a proto-oncogene overexpressed in numerous cancers. In this study, we explored the mechanism of insulin-induced Zbtb7A expression. Real-time PCR and western blotting were used to detect Zbtb7A expression. Zbtb7A promoter activity was monitored by Luciferase reporter assay. It was shown that insulin elevates the mRNA and protein levels of the Zbtb7A gene in HepG2 cells. Using chemical inhibitors of insulin downstream pathways, we demonstrated that the insulin‑induced Zbtb7A gene expression was completely blocked by LY294002, a PI3K/AKT inhibitor, and partially attenuated by the MAPK inhibitor PD98059. Transfection of HepG2 cells with a 1 kb Zbtb7A promoter-luciferase reporter construct revealed a dose‑dependent activation of the Zbtb7A promoter by insulin, while mutation of the Sp1 binding site within the Zbtb7A promoter resulted in the failure of insulin‑induced promoter activation, suggesting that insulin increases Zbtb7A expression through transcriptional regulation mediated by Sp1 in HepG2 cells.

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1	Maeda T, Hobbs RM, Merghoub T, et al: Role of the proto-oncogene Pokemon in cellular transformation and ARF repression. Nature. 433:278–285. 2005. View Article : Google Scholar : PubMed/NCBI
2	Morrison DJ, Pendergrast PS, Stavropoulos P, Colmenares SU, Kobayashi R and Hernandez N: FBI-1, a factor that binds to the HIV-1 inducer of short transcripts (IST), is a POZ domain protein. Nucleic Acids Res. 27:1251–1262. 1999. View Article : Google Scholar : PubMed/NCBI
3	Davies JM, Hawe N, Kabarowski J, et al: Novel BTB/POZ domain zinc-finger protein, LRF, is a potential target of the LAZ-3/BCL-6 oncogene. Oncogene. 18:365–375. 1999. View Article : Google Scholar : PubMed/NCBI
4	Kukita A, Kukita T, Ouchida M, Maeda H, Yatsuki H and Kohashi O: Osteoclast-derived zinc finger (OCZF) protein with POZ domain, a possible transcriptional repressor, is involved in osteoclastogenesis. Blood. 94:1987–1997. 1999.PubMed/NCBI
5	Pessler F, Pendergrast PS and Hernandez N: Purification and characterization of FBI-1, a cellular factor that binds to the human immunodeficiency virus type 1 inducer of short transcripts. Mol Cell Biol. 17:3786–3798. 1997.PubMed/NCBI
6	Apostolopoulou K, Pateras IS, Evangelou K, et al: Gene amplification is a relatively frequent event leading to ZBTB7A (Pokemon) overexpression in non-small cell lung cancer. J Pathol. 213:294–302. 2007. View Article : Google Scholar : PubMed/NCBI
7	Merghoub T, Cattoretti G, Piazza F, et al: Pokemon is required for cellular differentiation in multiple tissues. Blood. 98:792a2001.
8	Maeda T, Hobbs R, Merghoub T, et al: POKEMON is a proto-oncogene which plays a key role in lymphomagenesis. Blood. 104:951a2004.
9	Laudes M, Bilkovski R, Oberhauser F, et al: Transcription factor FBI-1 acts as a dual regulator in adipogenesis by coordinated regulation of cyclin-A and E2F-4. J Mol Med (Berlin). 86:597–608. 2008. View Article : Google Scholar : PubMed/NCBI
10	Jeon BN, Yoo JY, Choi WI, Lee CE, Yoon HG and Hur MW: Proto-oncogene FBI-1 (Pokemon/ZBTB7A) represses transcription of the tumor suppressor Rb gene via binding competition with Sp1 and recruitment of co-repressors. J Biol Chem. 283:33199–33210. 2008. View Article : Google Scholar : PubMed/NCBI
11	Choi WI, Jeon BN, Yun CO, et al: Proto-oncogene FBI-1 represses transcription of p21CIP1 by inhibition of transcription activation by p53 and Sp1. J Biol Chem. 284:12633–12644. 2009. View Article : Google Scholar : PubMed/NCBI
12	Roh HE, Lee MN, Jeon BN, et al: Regulation of Pokemon 1 activity by sumoylation. Cell Physiol Biochem. 20:167–180. 2007.PubMed/NCBI
13	Samson SL and Wong NC: Role of Sp1 in insulin regulation of gene expression. J Mol Endocrinol. 29:265–279. 2002. View Article : Google Scholar : PubMed/NCBI
14	Zu X, Yu L, Sun Q, et al: SP1 enhances Zbtb7A gene expression via direct binding to GC box in HePG2 cells. BMC Res Notes. 2:1752009. View Article : Google Scholar : PubMed/NCBI
15	Calera MR and Pilch PF: Induction of Akt-2 correlates with differentiation in Sol8 muscle cells. Biochem Biophys Res Commun. 251:835–841. 1998. View Article : Google Scholar : PubMed/NCBI
16	Roche S, Downward J, Raynal P and Courtneidge SA: A function for phosphatidylinositol 3-kinase beta (p85alpha-p110beta) in fibroblasts during mitogenesis: requirement for insulin- and lysophosphatidic acid-mediated signal transduction. Mol Cell Biol. 18:7119–7129. 1998.
17	Rother KI, Imai Y, Caruso M, Beguinot F, Formisano P and Accili D: Evidence that IRS-2 phosphorylation is required for insulin action in hepatocytes. J Biol Chem. 273:17491–17497. 1998. View Article : Google Scholar : PubMed/NCBI
18	Slieker LJ, Sloop KW and Surface PL: Differentiation method-dependent expression of leptin in adipocyte cell lines. Biochem Biophys Res Commun. 251:225–229. 1998. View Article : Google Scholar : PubMed/NCBI
19	Rosen OM: After insulin binds. Science. 237:1452–1458. 1987. View Article : Google Scholar : PubMed/NCBI
20	O’Brien RM and Granner DK: Regulation of gene expression by insulin. Physiol Rev. 76:1109–1161. 1996.
21	Koontz JW and Iwahashi M: Insulin as a potent, specific growth factor in a rat hepatoma cell line. Science. 211:947–949. 1981. View Article : Google Scholar : PubMed/NCBI
22	Block GD, Locker J, Bowen WC, et al: Population expansion, clonal growth, and specific differentiation patterns in primary cultures of hepatocytes induced by HGF/SF, EGF and TGF alpha in a chemically defined (HGM) medium. J Cell Biol. 132:1133–1149. 1996. View Article : Google Scholar
23	Scassa ME, Guberman AS, Varone CL and Cánepa ET: Phosphatidylinositol 3-kinase and Ras/mitogen-activated protein kinase signaling pathways are required for the regulation of 5-aminolevulinate synthase gene expression by insulin. Exp Cell Res. 271:201–213. 2001. View Article : Google Scholar : PubMed/NCBI
24	Saltiel AR and Pessin JE: Insulin signaling pathways in time and space. Trends Cell Biol. 12:65–71. 2002. View Article : Google Scholar : PubMed/NCBI
25	Boyd DB: Insulin and cancer. Integr Cancer Ther. 2:315–329. 2003. View Article : Google Scholar
26	Thompson AD III and Kakar SS: Insulin and IGF-1 regulate the expression of the pituitary tumor transforming gene (PTTG) in breast tumor cells. FEBS Lett. 579:3195–3200. 2005. View Article : Google Scholar : PubMed/NCBI
27	Messina JL: Inhibition and stimulation of c-myc gene transcription by insulin in rat hepatoma cells. Insulin alters the intragenic pausing of c-myc transcription. J Biol Chem. 266:17995–18001. 1991.PubMed/NCBI
28	Saltiel AR and Kahn CR: Insulin signalling and the regulation of glucose and lipid metabolism. Nature. 414:799–806. 2001. View Article : Google Scholar : PubMed/NCBI
29	Sun J and Jin T: Both Wnt and mTOR signaling pathways are involved in insulin-stimulated proto-oncogene expression in intestinal cells. Cell Signal. 20:219–229. 2008. View Article : Google Scholar : PubMed/NCBI
30	Zhao ZH, Wang SF, Yu L, et al: Overexpression of Pokemon in non-small cell lung cancer and foreshowing tumor biological behavior as well as clinical results. Lung Cancer. 62:113–119. 2008. View Article : Google Scholar : PubMed/NCBI
31	Flegal KM, Carroll MD, Kuczmarski RJ and Johnson CL: Overweight and obesity in the United States: prevalence and trends, 1960–1994. Int J Obes Relat Metab Disord. 22:39–47. 1998.
32	Mason AL, Lau JY, Hoang N, et al: Association of diabetes mellitus and chronic hepatitis C virus infection. Hepatology. 29:328–333. 1999. View Article : Google Scholar : PubMed/NCBI
33	Michalopoulos GK and DeFrances MC: Liver regeneration. Science. 276:60–66. 1997. View Article : Google Scholar
34	Motoo Y, Kobayashi K and Hattori N: Effect of insulin on the growth of a human hepatoma cell line PLC/PRF/5: a possible role of insulin receptor. Tohoku J Exp Med. 156:351–357. 1988. View Article : Google Scholar : PubMed/NCBI
35	Spydevold O, Sørensen H, Clausen OP and Gautvik KM: Dexamethasone inhibition of rat hepatoma cell growth and cell cycle traverse is reversed by insulin. Biochim Biophys Acta. 1052:221–228. 1990. View Article : Google Scholar : PubMed/NCBI
36	Au WS, Kung HF and Lin MC: Regulation of microsomal triglyceride transfer protein gene by insulin in HepG2 cells: roles of MAPKerk and MAPKp38. Diabetes. 52:1073–1080. 2003. View Article : Google Scholar : PubMed/NCBI