title: Constitutive production of parathyroid hormone-related protein (PTHrP) by fibroblasts derived from normal and pathological human breast tissue.
abstract: Parathyroid hormone-related protein (PTHrP) is expressed in the mammary gland and appears to be critical to the morphogenesis of this structure. PTHrP production in the breast is generally attributed to epithelial cells. Because the stromal component of the breast produces factors implicated in proliferation and differentiation of mammary epithelial tissue and tumors, the aim of this study was to investigate the PTHrP expression by mammary fibroblasts from breast cancer tumors and normal breast. PTHrP antibodies labeled intralobular fibroblasts in normal breast and stromal fibroblasts that surround tumor cells. PTHrP was constitutively produced by the cultured mammary fibroblasts, independent of serum stimulation. Normal (15.83 +/- 1.72 fmol/10(6) cells) and pathological breast fibroblasts (19.87 +/- 5.76) secreted similar amounts of PTHrP. PTH/PTHrP receptor mRNA was detected by RT-PCR in all the samples tested. Fibroblasts from normal breast were both PTH and PTHrP-cAMP responsive (453 +/- 133% and 513 +/- 133%, respectively, from basal stimulation), whereas pathological breast fibroblasts were minimally PTHrP-cAMP responsive (183 +/- 36%). The production of other fibroblastic factors implicated in tumor growth and invasiveness was also examined. Interleukin-6 (IL-6), tumor necrosis factor-alpha (INF-alpha), and pro-matrix metalloproteinase (MMP)-1 were not affected by the status of the tissue. In contrast, increased levels of pro-MMP-2 were produced in fibroblasts that originated from pathological (290 +/- 62 ng/10(6) cells) samples compared with those from normal donors (125 +/- 41 ng/10(6) cells). PTHrP production was correlated with TNF-alpha and pro-MMP-2 production. However, inhibition with specific neutralizing antibodies against TNF-alpha or PTHrP, or with a PTHrP antagonist, showed that these factors did not regulate each other. In conclusion, breast fibroblasts are constitutive PTHrP-producing cells with the potential for autocrine signaling through the PTH/PTHrP receptor.
authors.affiliation: INSERM U349, Laboratoire de Biologie Cellulaire et Moléculaire de l'Os et du Cartilage, Hôpital Lariboisière, 75475 Paris Cedex 10, France.
authors.forename: Magali
authors.initials: M
authors.lastname: Cros
authors.forename: Christophe
authors.initials: C
authors.lastname: Cataisson
authors.forename: Yong Mee
authors.initials: YM
authors.lastname: Cho
authors.forename: Yolande
authors.initials: Y
authors.lastname: Berthois
authors.forename: Oana
authors.initials: O
authors.lastname: Bernard-Poenaru
authors.forename: Maryannick
authors.initials: M
authors.lastname: Denne
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Graulet
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: De Vernejoul
authors.forename: John
authors.initials: J
authors.lastname: Foley
authors.forename: Zhor
authors.initials: Z
authors.lastname: Bouizar
mesh_terms: D000906:Antibodies / Q000494:pharmacology; D001940:Breast / Q000166:cytology / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism; D004792:Enzyme Precursors / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D010281:Parathyroid Hormone / Q000494:pharmacology; D044162:Parathyroid Hormone-Related Protein; D036361:Peptide Hormones / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D044168:Receptor, Parathyroid Hormone, Type 1; D018016:Receptors, Parathyroid Hormone / Q000235:genetics / Q000378:metabolism; D012016:Reference Values; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000378:metabolism
chemical_list: D000906:Antibodies; D016207:Cytokines; D004792:Enzyme Precursors; C470121:PTHLH protein, human; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D036361:Peptide Hormones; D044168:Receptor, Parathyroid Hormone, Type 1; D018016:Receptors, Parathyroid Hormone; D014409:Tumor Necrosis Factor-alpha; D000242:Cyclic AMP; D010450:Endopeptidases; D020778:Matrix Metalloproteinase 2; D020781:Matrix Metalloproteinase 1