title: Beta-adrenergic and arachidonic acid-mediated growth regulation of human breast cancer cell lines.
abstract: Adenocarcinoma of the mammary gland is the leading type of cancer in women. Among these breast cancers those that are estrogen-responsive respond well to existing therapeutic regimens while estrogen non-responsive cancers metastasize widely, demonstrate a high relapse rate, and respond poorly to therapy. Over-expression of the arachidonic acid-metabolizing enzymes cyclooxygenase-2 and lypoxygenases is frequently observed in breast cancer, particularly the non-estrogen-responsive type, suggesting a role of the arachidonic acid (AA) cascade in the growth regulation of these malignancies. Adenocarcinomas of the lungs, pancreas and colon also frequently over-express AA-metabolizing enzymes, and recent evidence suggests that the growth-regulating AA-cascade in these malignancies is under beta-adrenergic control. Our current experiments have therefore tested the hypothesis that in analogy to these findings adenocarcinomas of the breast are also regulated by beta-adrenergic receptors via stimulation of the AA-cascade. Analysis of DNA synthesis by [3H]-thymidine incorporation assays in three estrogen-responsive and three estrogen non-responsive cell lines derived from human breast cancers demonstrated a significant reduction in DNA synthesis by beta-blockers and inhibitors of cyclooxygenase or lipoxygenases in all cell lines. Analysis of AA-release in one of the most responsive cell lines demonstrated a time-dependent increase in AA-release in response to the beta-adrenergic agonist isoproterenol. Analysis by RT-PCR revealed expression of beta2-adrenergic receptors in all cell lines whereas beta1-adrenergic receptors were not found in two of the estrogen non-responsive cell lines. Our data suggest that a significant subset of human breast cancers is under control of beta-adrenergic receptors via stimulation of the AA-cascade. These findings open up novel avenues for the prevention and clinical management of breast cancer, particularly the non-estrogen-responsive types. Moreover, our findings suggest that cardiovascular disease and adenocarcinomas in a variety of organ systems, including the breast may share common risk factors and benefit from similar preventive and treatment strategies.
authors.affiliation: Experimental Oncology Laboratory, Carcinogenesis and Developmental Therapeutics Program, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Cakir
authors.forename: H K
authors.initials: HK
authors.lastname: Plummer
authors.forename: P K
authors.initials: PK
authors.lastname: Tithof
authors.forename: H M
authors.initials: HM
authors.lastname: Schuller
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism; D016718:Arachidonic Acid / Q000378:metabolism*; D001241:Aspirin / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis; D004261:DNA Replication / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors; D007545:Isoproterenol / Q000494:pharmacology; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology*; D008565:Membrane Proteins; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases; D012333:RNA, Messenger / Q000378:metabolism; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D004967:Estrogens; D007527:Isoenzymes; D016859:Lipoxygenase Inhibitors; D008565:Membrane Proteins; D012333:RNA, Messenger; D018343:Receptors, Adrenergic, beta-2; D016718:Arachidonic Acid; D004247:DNA; D001094:Arachidonate 5-Lipoxygenase; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D007545:Isoproterenol; D001241:Aspirin