Constitutive production of parathyroid hormone-related protein (PTHrP) by fibroblasts derived from normal and pathological human breast tissue.
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.
Cros
Magali
M
INSERM U349, Laboratoire de Biologie Cellulaire et Moléculaire de l'Os et du Cartilage, Hôpital Lariboisière, 75475 Paris Cedex 10, France.
Cataisson
Christophe
C
Cho
Yong Mee
YM
Berthois
Yolande
Y
Bernard-Poenaru
Oana
O
Denne
Maryannick
M
Graulet
Anne-Marie
AM
De Vernejoul
Marie-Christine
MC
Foley
John
J
Bouizar
Zhor
Z
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
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