Adrenomedullin inhibits hypoxic cell death by upregulation of Bcl-2 in endometrial cancer cells: a possible promotion mechanism for tumour growth

Regions of hypoxia are a common feature of solid tumours. When tumour cells are exposed to hypoxic stress, transcription of a battery of genes is initiated. The angiogenic factor adrenomedullin (ADM) is a hypoxia regulated gene. ADM is thought to act through the G protein-coupled receptor calcitonin receptor-like receptor (CRLR), with specificity being conferred by the receptor associated modifying protein 2 (RAMP2). Here we report for the first time that ADM treated or stably transfected Ishikawa cells overexpressing ADM show increased resistance to hypoxia induced apoptosis. These cells also show an upregulation of the oncoprotein Bcl-2, which is protective against hypoxic cell death when transiently transfected into Ishikawa cells. Since Ishikawa cells express the putative ADM-receptor CRLR–RAMP2 the production and secretion of ADM with the consecutive upregulation of Bcl-2 could establish an autocrine/paracrine mechanism rescuing malignant cells from hypoxic cell death. These results, taken together with our previous findings that ADM is an angiogenic factor which is upregulated by the nonsteroidal antiestrogen tamoxifen (TAM) in endometrial cells, implicate this peptide as a promoter of tumour growth and a possible target for anticancer strategies.

[1]  R. Jäger,et al.  Overexpression of Bcl-2 inhibits alveolar cell apoptosis during involution and accelerates c-myc-induced tumorigenesis of the mammary gland in transgenic mice , 1997, Oncogene.

[2]  F. Cuttitta,et al.  Modulation of Endometrial Steroid Receptors and Growth Regulatory Genes by Tamoxifen , 2000, Obstetrics and gynecology.

[3]  Dean P. Jones,et al.  Prevention of Apoptosis by Bcl-2: Release of Cytochrome c from Mitochondria Blocked , 1997, Science.

[4]  M. Shichiri,et al.  Adrenomedullin as an autocrine/paracrine apoptosis survival factor for rat endothelial cells. , 1997, Endocrinology.

[5]  Y. Tsujimoto,et al.  Prevention of hypoxic liver cell necrosis by in vivo human bcl-2 gene transfection. , 1998, Biochemical and biophysical research communications.

[6]  O. Smithies,et al.  Extreme hydrops fetalis and cardiovascular abnormalities in mice lacking a functional Adrenomedullin gene. , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[7]  A. Kurtz,et al.  Tissue hypoxygenation activates the adrenomedullin system in vivo. , 2000, American journal of physiology. Regulatory, integrative and comparative physiology.

[8]  R. Barakat.  Tamoxifen and endometrial neoplasia. , 1996, Clinical obstetrics and gynecology.

[9]  L. K. Larsen,et al.  Improved RNase protection assay for quantifying LDL-receptor mRNA; estimation of analytical imprecision and biological variance in peripheral blood mononuclear cells. , 1995, Clinical chemistry.

[10]  Y. Tsujimoto,et al.  Prevention of hypoxia-induced cell death by Bcl-2 and Bcl-xL , 1995, Nature.

[11]  Beverly A. Teicher,et al.  Drug resistance in oncology , 1993 .

[12]  M. Asakawa,et al.  The RAMP2/CRLR complex is a functional adrenomedullin receptor in human endothelial and vascular smooth muscle cells , 1999, FEBS letters.

[13]  Lyna Zhang,et al.  PCR display identifies tamoxifen induction of the novel angiogenic factor adrenomedullin by a non estrogenic mechanism in the human endometrium , 1998, Oncogene.

[14]  Y. Tsujimoto,et al.  Induction of apoptosis as well as necrosis by hypoxia and predominant prevention of apoptosis by Bcl-2 and Bcl-XL. , 1996, Cancer research.

[15]  W. Claycomb,et al.  Hypoxia regulates the expression of the adrenomedullin and HIF-1 genes in cultured HL-1 cardiomyocytes. , 1999, Biochemical and biophysical research communications.

[16]  D. Fisher,et al.  Apoptosis in tumorigenesis and cancer therapy. , 1997, Frontiers in bioscience : a journal and virtual library.

[17]  M. Gassmann,et al.  Hypoxia-inducible factor-1 (HIF-1) up-regulates adrenomedullin expression in human tumor cell lines during oxygen deprivation: a possible promotion mechanism of carcinogenesis. , 2000, Molecular endocrinology.

[18]  David E. Housman,et al.  Hypoxia-mediated selection of cells with diminished apoptotic potential in solid tumours , 1996, Nature.

[19]  K. Kangawa,et al.  Adrenomedullin: a novel hypotensive peptide isolated from human pheochromocytoma. , 1993, Biochemical and biophysical research communications.

[20]  D. Hanahan,et al.  The rise and fall of apoptosis during multistage tumorigenesis: down-modulation contributes to tumor progression from angiogenic progenitors. , 1996, Genes & development.

[21]  T. Graeber,et al.  Modulation of c-Myc activity and apoptosis in vivo. , 1996, Cancer research.

[22]  T. Ishimitsu,et al.  Genomic structure of human adrenomedullin gene. , 1994, Biochemical and biophysical research communications.

[23]  D. Brooks,et al.  Regulation of glomerular mesangial cell proliferation in culture by adrenomedullin. , 1999, European journal of pharmacology.

[24]  B. Ebert,et al.  Regulation of angiogenic growth factor expression by hypoxia, transition metals, and chelating agents. , 1995, The American journal of physiology.

[25]  P. Bendel,et al.  Tamoxifen induced changes in MCF7 human breast cancer: In vitro and in vivo studies using nuclear magnetic resonance spectroscopy and imaging , 1992, The Journal of Steroid Biochemistry and Molecular Biology.

[26]  H. Watari,et al.  Bcl‐2 expression and prognosis of patients with endometrial carcinoma , 1998, International journal of cancer.

[27]  S. Wimalawansa,et al.  Amylin, calcitonin gene-related peptide, calcitonin, and adrenomedullin: a peptide superfamily. , 1997, Critical reviews in neurobiology.

[28]  C. Koch,et al.  Tamoxifen induces hypoxia in MCF-7 xenografts. , 1997, Cancer Research.

[29]  Frank Cuttitta,et al.  Adrenomedullin Expression in Human Tumor Cell Lines ITS POTENTIAL ROLE AS AN AUTOCRINE GROWTH FACTOR* , 1996, The Journal of Biological Chemistry.

[30]  I. White,et al.  Tamoxifen induces endometrial and vaginal cancer in rats in the absence of endometrial hyperplasia. , 2000, Carcinogenesis.

[31]  W. Claycomb,et al.  Adrenomedullin Gene Expression Is Developmentally Regulated and Induced by Hypoxia in Rat Ventricular Cardiac Myocytes* , 1998, The Journal of Biological Chemistry.

[32]  L. Zhang,et al.  Expression of the hypoxically regulated angiogenic factor adrenomedullin correlates with uterine leiomyoma vascular density. , 2000, Clinical cancer research : an official journal of the American Association for Cancer Research.

[33]  D. Smith,et al.  Adrenomedullin, a multifunctional regulatory peptide. , 2000, Endocrine reviews.

[34]  D. Mooney,et al.  Vascular endothelial growth factor (VEGF)-mediated angiogenesis is associated with enhanced endothelial cell survival and induction of Bcl-2 expression. , 1999, The American journal of pathology.

[35]  D. Vaux,et al.  Insights from Bcl-2 and Myc: malignancy involves abrogation of apoptosis as well as sustained proliferation. , 1999, Cancer research.

[36]  A. Ricca,et al.  bcl‐2 over‐expression enhances NF‐κB activity and induces mmp‐9 transcription in human MCF7ADR breast‐cancer cells , 2000, International journal of cancer.

[37]  Harry Hollema,et al.  Risk and prognosis of endometrial cancer after tamoxifen for breast cancer , 2000, The Lancet.

[38]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[39]  K. Takahashi,et al.  Induction of adrenomedullin by hypoxia and cobalt chloride in human colorectal carcinoma cells. , 1998, Biochemical and biophysical research communications.

[40]  Melanie G. Lee,et al.  RAMPs regulate the transport and ligand specificity of the calcitonin-receptor-like receptor , 1998, Nature.

[41]  M. Shichiri,et al.  Induction of max by adrenomedullin and calcitonin gene-related peptide antagonizes endothelial apoptosis. , 1999, Molecular endocrinology.

[42]  S. Cory,et al.  The Bcl-2 protein family: arbiters of cell survival. , 1998, Science.

[43]  J. Cuzick.  A brief review of the current breast cancer prevention trials and proposals for future trials. , 2000, European journal of cancer.

[44]  L. H. Gray,et al.  The Histological Structure of Some Human Lung Cancers and the Possible Implications for Radiotherapy , 1955, British Journal of Cancer.