The levels of the endocannabinoid receptor CB2 and its ligand 2-arachidonoylglycerol are elevated in endometrial carcinoma.

The endocannabinoid system plays protective roles against the growth and the spreading of several types of carcinomas. Because estrogens regulate this system both in physiological states and cancer, in this paper we evaluated its involvement in endometrial carcinoma, a well-known estrogen-dependent tumor. To test whether the endocannabinoid system is expressed in endometrial cancer, tissue samples were collected both from 18 patients undergoing surgical treatment for endometrial adenocarcinoma and 16 healthy age-matched controls, and treated for Western blot and immunohistochemical analysis. Moreover, tissues were dounce homogenized and submitted to endocannabinoid measurement by liquid chromatography-mass spectrometry. To evaluate the physiological role of the endocannabinoid system, a human endometrial cancer cell-line (AN3CA) was used and transiently transfected with a plasmid containing the cDNA for the endocannabinoid receptor CB(2). Cells were incubated for 48 h with an agonist (JWH133) (10 mum) or antagonist (SR144528) (1 mum) of CB(2) 24 h after transfection, and cell proliferation was measured by the 3-[4,5-dimethyltiazol-2yl]-2,5 diphenyltetrazolium bromide formazan assay. In human endometrial carcinoma biopsies the expression of CB(2) receptor and the levels of its ligand, 2-arachidonoylglycerol increased, whereas monoacylglycerol lipase, an enzyme responsible for 2-arachidonoylglycerol degradation, was down-regulated. Immunohistochemical analysis revealed that CB(2) was overexpressed only in malignant endometrial cells. CB(2)-overexpressing AN3CA cells showed a significant reduction in cell vitality compared with parental AN3CA cells: incubation with the selective CB(2) antagonist SR144128 restored the viability of CB(2)-overexpressing cells to that of untransfected cells. In conclusion, the endocannabinoid system seems to play an important role in human endometrial carcinoma, and modulation of CB(2) activity/expression may account for a tumor-suppressive effect.

[1]  B. Cravatt,et al.  Transcriptional regulation of the mouse fatty acid amide hydrolase gene. , 2002, Gene.

[2]  M. De Felici,et al.  Down-regulation of anandamide hydrolase in mouse uterus by sex hormones. , 2000, European journal of biochemistry.

[3]  R. Pertwee,et al.  Pharmacological actions of cannabinoids. , 2005, Handbook of experimental pharmacology.

[4]  N. Weiss,et al.  Long-term use of postmenopausal estrogen and progestin hormone therapies and the risk of endometrial cancer. , 2007, American journal of obstetrics and gynecology.

[5]  S. Munro,et al.  Molecular characterization of a peripheral receptor for cannabinoids , 1993, Nature.

[6]  I. Galve-Roperh,et al.  Cannabinoids and cell fate. , 2002, Pharmacology & therapeutics.

[7]  Jaime Prat,et al.  Prognostic parameters of endometrial carcinoma. , 2004, Human pathology.

[8]  M. Guzmán,et al.  Cannabinoids: potential anticancer agents , 2003, Nature Reviews Cancer.

[9]  B. Sander,et al.  The endocannabinoid system in cancer-potential therapeutic target? , 2008, Seminars in cancer biology.

[10]  V. Adhami,et al.  Cannabinoids for cancer treatment: progress and promise. , 2008, Cancer research.

[11]  F. Pentimalli,et al.  Endocannabinoids as emerging suppressors of angiogenesis and tumor invasion (review). , 2007, Oncology reports.

[12]  R. Ganju,et al.  Δ9-Tetrahydrocannabinol inhibits epithelial growth factor-induced lung cancer cell migration in vitro as well as its growth and metastasis in vivo , 2008, Oncogene.

[13]  G. Velasco,et al.  Hypothesis: cannabinoid therapy for the treatment of gliomas? , 2004, Neuropharmacology.

[14]  T. Bisogno,et al.  Possible endocannabinoid control of colorectal cancer growth. , 2003, Gastroenterology.

[15]  J. Trojan,et al.  Evaluation of angiogenesis, p-53 tissue protein expression and serum VEGF in patients with endometrial cancer. , 2004, Neoplasma.

[16]  J. Girault,et al.  Regulation of Extracellular Signal-Regulated Kinase by Cannabinoids in Hippocampus , 2003, The Journal of Neuroscience.

[17]  M. L. de Ceballos,et al.  Inhibition of glioma growth in vivo by selective activation of the CB(2) cannabinoid receptor. , 2001, Cancer research.

[18]  F. Berrendero,et al.  Decreased Cannabinoid CB1 Receptor mRNA Levels and Immunoreactivity in Pituitary Tumors Induced by Prolonged Exposure to Estrogens , 2000, Pituitary.

[19]  S. Petrosino,et al.  Endocannabinoids and the regulation of their levels in health and disease , 2007, Current opinion in lipidology.

[20]  M. Guida,et al.  Selective CB2 up-regulation in women affected by endometrial inflammation , 2007, Journal of cellular and molecular medicine.

[21]  M. Malumbres,et al.  Cannabinoid receptors as novel targets for the treatment of melanoma , 2006, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[22]  A. Franchi,et al.  17beta-oestradiol and progesterone regulate anandamide synthesis in the rat uterus. , 2009, Reproductive biomedicine online.

[23]  C. Adra,et al.  Anti-inflammatory potential of CB1-mediated cAMP elevation in mast cells. , 2005, The Biochemical journal.

[24]  T. Bonner,et al.  Structure of a cannabinoid receptor and functional expression of the cloned cDNA , 1990, Nature.

[25]  V. Marzo,et al.  Targeting the endocannabinoid system in cancer therapy: A call for further research , 2002, Nature Medicine.

[26]  A. Taylor,et al.  Localisation and Function of the Endocannabinoid System in the Human Ovary , 2009, PloS one.

[27]  Soichi Obara,et al.  Anandamide induces apoptosis of PC‐12 cells: involvement of superoxide and caspase‐3 , 2000, FEBS letters.

[28]  A. Carracedo,et al.  Cannabinoids inhibit glioma cell invasion by down-regulating matrix metalloproteinase-2 expression. , 2008, Cancer research.

[29]  T. Bisogno,et al.  Cannabinoid CB1 receptor stimulation affords neuroprotection in MPTP-induced neurotoxicity by attenuating S100B up-regulation in vitro , 2007, Journal of Molecular Medicine.

[30]  S. Dey,et al.  Aspects of endocannabinoid signaling in periimplantation biology , 2008, Molecular and Cellular Endocrinology.

[31]  C. Lunn,et al.  Targeting the CB2 receptor for immune modulation , 2006, Expert opinion on therapeutic targets.

[32]  R. Ness,et al.  Inflammation and Endometrial Cancer: A Hypothesis , 2005, Cancer Epidemiology Biomarkers & Prevention.

[33]  Saori Oka,et al.  Biochemistry, pharmacology and physiology of 2-arachidonoylglycerol, an endogenous cannabinoid receptor ligand. , 2006, Progress in lipid research.

[34]  G. Morrill,et al.  Effects of cannabinoids on reproduction and development. , 1978, Vitamins and hormones.

[35]  Michael T. Fisher,et al.  Targeting CB2 cannabinoid receptors as a novel therapy to treat malignant lymphoblastic disease. , 2002, Blood.

[36]  C. Foresta,et al.  Human sperm express cannabinoid receptor Cb1, the activation of which inhibits motility, acrosome reaction, and mitochondrial function. , 2005, The Journal of clinical endocrinology and metabolism.