Influence of the mycotoxins α- and β-zearalenol (ZOL) on regulators of cap-dependent translation control in pig endometrial cells

The molecular mechanisms that control the mycotoxin-mediated effects in porcine endometrial cells are far from being completely understood. Recent results show that they could inhibit cell proliferation. Therefore, the present study investigated the effects of the mycotoxins alpha-zearalenol (alpha-ZOL) and beta-zearalenol (beta-ZOL) on a cellular level. Mainly, the abundance and phosphorylation state (activity) of the cell cycle-dependent kinases MAPK and Akt (PKB) and their potential targets eIF4E (eukaryotic initiation factor 4E) and 4E-BP1 (4E binding protein, eIF4E repressor protein) were investigated. The results show that alpha-ZOL has apparently only a slight influence on the phosphorylation state of MAP kinases, Akt and on eIF4E and 4E-BP1. In contrast, their phosphorylation was strongly reduced in beta-ZOL-treated cells in a concentration-dependent manner. Therefore, our results indicate that beta-ZOL potentially not only influences transcription but also effects gene expression on translational level. The effect of alpha- and beta-ZOL on endometrial cell proliferation and their toxicology are discussed.

[1]  A. Gingras,et al.  eIF4 initiation factors: effectors of mRNA recruitment to ribosomes and regulators of translation. , 1999, Annual review of biochemistry.

[2]  M. Polymenis,et al.  Coordination of cell growth with cell division. , 1999, Current opinion in genetics & development.

[3]  C. Proud,et al.  Protein phosphorylation in translational control. , 1992, Current topics in cellular regulation.

[4]  A. Gingras,et al.  4E-BP1, a repressor of mRNA translation, is phosphorylated and inactivated by the Akt(PKB) signaling pathway. , 1998, Genes & development.

[5]  L. Murphy,et al.  Measurement of the relative binding affinity of zearalenone, alpha-zearalenol and beta-zearalenol for uterine and oviduct estrogen receptors in swine, rats and chickens: an indicator of estrogenic potencies. , 1989, Comparative biochemistry and physiology. C, Comparative pharmacology and toxicology.

[6]  O. Kayisli,et al.  In Vivo and In Vitro Regulation of Akt Activation in Human Endometrial Cells Is Estrogen Dependent , 2004, Biology of reproduction.

[7]  J. Warwicker,et al.  A Quantitative Molecular Model for Modulation of Mammalian Translation by the eIF4E-binding Protein 1* , 2001, The Journal of Biological Chemistry.

[8]  A. Gingras,et al.  Insulin-dependent stimulation of protein synthesis by phosphorylation of a regulator of 5'-cap function , 1994, Nature.

[9]  F. Schneider,et al.  Effects of organochlorine pesticides on DNA synthesis of cultured oviductal and uterine cells and on estrogen receptor of uterine tissue from heifers , 1996, Archives of Toxicology.

[10]  Y. Taketani,et al.  Akt as a possible intracellular mediator for decidualization in human endometrial stromal cells. , 2003, Molecular human reproduction.

[11]  A. Schulze,et al.  Cell cycle regulation of the cyclin A gene promoter is mediated by a variant E2F site. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[12]  R. Watson,et al.  Cell cycle regulation by the B-Myb transcription factor , 2003, Cellular and Molecular Life Sciences CMLS.

[13]  W. Rychlik,et al.  Alteration of the major phosphorylation site of eukaryotic protein synthesis initiation factor 4E prevents its association with the 48 S initiation complex. , 1990, The Journal of biological chemistry.

[14]  N. Sonenberg,et al.  Cell-cycle-dependent translational control. , 2001, Current opinion in genetics & development.

[15]  J. Pestka,et al.  Toxicology of deoxynivalenol (vomitoxin). , 1996, Journal of toxicology and environmental health.

[16]  Jonathan A. Cooper,et al.  The Phosphorylation of Eukaryotic Initiation Factor eIF4E in Response to Phorbol Esters, Cell Stresses, and Cytokines Is Mediated by Distinct MAP Kinase Pathways* , 1998, The Journal of Biological Chemistry.

[17]  C. Dees,et al.  Dietary estrogens stimulate human breast cells to enter the cell cycle. , 1997, Environmental health perspectives.

[18]  Jonathan A. Cooper,et al.  Phosphorylation of the Cap-Binding Protein Eukaryotic Translation Initiation Factor 4E by Protein Kinase Mnk1 In Vivo , 1999, Molecular and Cellular Biology.

[19]  T. Viergutz,et al.  Influence of the mycotoxins α- and β-zearalenol and deoxynivalenol on the cell cycle of cultured porcine endometrial cells , 2003 .

[20]  F. Schneider,et al.  Influence of organochlorine pesticides on physiological potency of cultured granulosa cells from bovine preovulatory follicles. , 1996, Theriogenology.

[21]  A. Gingras,et al.  Human eukaryotic translation initiation factor 4G (eIF4G) recruits Mnk1 to phosphorylate eIF4E , 1999, The EMBO journal.

[22]  M. Anger,et al.  Regulation of Translation During In Vitro Maturation of Bovine Oocytes: The Role of MAP Kinase, eIF4E (Cap Binding Protein) Phosphorylation, and eIF4E-BP11 , 2002, Biology of reproduction.

[23]  A. Gingras,et al.  Requirement for Akt (Protein Kinase B) in Insulin-induced Activation of Glycogen Synthase and Phosphorylation of 4E-BP1 (PHAS-1)* , 1999, The Journal of Biological Chemistry.

[24]  R L Juliano,et al.  Cell adhesion molecules, signal transduction and cell growth. , 1999, Current opinion in cell biology.

[25]  P. Anderson,et al.  Trichothecene Mycotoxins Trigger a Ribotoxic Stress Response That Activates c-Jun N-terminal Kinase and p38 Mitogen-activated Protein Kinase and Induces Apoptosis* , 1999, The Journal of Biological Chemistry.

[26]  P. Scott,et al.  Risk assessment of the mycotoxin zearalenone. , 1987, Regulatory toxicology and pharmacology : RTP.

[27]  S. Kimball,et al.  Regulation of translation initiation by amino acids in eukaryotic cells. , 2001, Progress in molecular and subcellular biology.

[28]  M. Schwartz,et al.  Integrins and cell proliferation: regulation of cyclin-dependent kinases via cytoplasmic signaling pathways. , 2001, Journal of cell science.

[29]  G. Scheper,et al.  The Mitogen-Activated Protein Kinase Signal-Integrating Kinase Mnk2 Is a Eukaryotic Initiation Factor 4E Kinase with High Levels of Basal Activity in Mammalian Cells , 2001, Molecular and Cellular Biology.

[30]  L. New,et al.  Phosphorylation of eIF-4E on Ser 209 in response to mitogenic and inflammatory stimuli is faithfully detected by specific antibodies. , 2000, Molecular cell biology research communications : MCBRC.

[31]  D. Bhatnagar,et al.  Mycotoxins in Agriculture and Food Safety , 1998 .

[32]  G. Scheper,et al.  Phosphorylation of Eukaryotic Initiation Factor 4E Markedly Reduces Its Affinity for Capped mRNA* , 2002, The Journal of Biological Chemistry.

[33]  T. Haystead,et al.  Identification of Phosphorylation Sites in the Translational Regulator, PHAS-I, That Are Controlled by Insulin and Rapamycin in Rat Adipocytes* , 1997, The Journal of Biological Chemistry.

[34]  H. Trachsel,et al.  Altered mRNA cap recognition activity of initiation factor 4E in the yeast cell cycle division mutant cdc33. , 1989, Nucleic acids research.

[35]  T. Viergutz,et al.  Fluorometric detection of platelet activating factor receptor in cultured oviductal epithelial and stromal cells and endometrial stromal cells from bovine at different stages of the oestrous cycle and early pregnancy. , 2001, Domestic animal endocrinology.

[36]  Wen-rong Gong,et al.  Activation of the Src/p21ras/Erk pathway by progesterone receptor via cross‐talk with estrogen receptor , 1998, The EMBO journal.

[37]  N. Sonenberg,et al.  eIF4G Dramatically Enhances the Binding of eIF4E to the mRNA 5′-Cap Structure* , 1997, The Journal of Biological Chemistry.

[38]  G. Gibori,et al.  PRL antiapoptotic effect in the rat decidua involves the PI3K/protein kinase B-mediated inhibition of caspase-3 activity. , 2001, Endocrinology.

[39]  Cheorl-Ho Kim,et al.  ERK1/2 mediates TNF‐α‐induced matrix metalloproteinase‐9 expression in human vascular smooth muscle cells via the regulation of NF‐κB and AP‐1: Involvement of the ras dependent pathway , 2004, Journal of cellular physiology.

[40]  J. Marks,et al.  Inhibition of mitogen-activated protein kinase and phosphatidylinositol 3-kinase activity in MCF-7 cells prevents estrogen-induced mitogenesis. , 2000, Cell growth & differentiation : the molecular biology journal of the American Association for Cancer Research.

[41]  M. Kastan,et al.  Participation of ATM in insulin signalling through phosphorylation of eIF-4E-binding protein 1 , 2000, Nature Cell Biology.

[42]  M. M. Bradford.  A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.

[43]  C. Proud,et al.  The Extracellular Signal-regulated Kinase Pathway Regulates the Phosphorylation of 4E-BP1 at Multiple Sites* , 2002, The Journal of Biological Chemistry.

[44]  J. S. Foster,et al.  Signal transduction through the ras/Erk pathway is essential for the mycoestrogen zearalenone‐induced cell‐cycle progression in MCF‐7 cells , 2001, Molecular carcinogenesis.

[45]  A. Gingras,et al.  The mRNA 5' cap-binding protein eIF4E and control of cell growth. , 1998, Current opinion in cell biology.

[46]  L. McKendrick,et al.  Involvement of Stress-activated Protein Kinase and p38/RK Mitogen-activated Protein Kinase Signaling Pathways in the Enhanced Phosphorylation of Initiation Factor 4E in NIH 3T3 Cells* , 1997, The Journal of Biological Chemistry.