Autocrine production of prostaglandin F2{alpha} enhances phenotypic transformation of normal rat kidney fibroblasts

• Published in: American Journal of Physiology: Cell Physiology 2005-07, Vol.289 (1), p.C130
• Main Authors: Harks, E. G. A, Peters, P. H. J, van Dongen, J. L. J, van Zoelen, E. J. J, Theuvenet, A. P. R
• Format: Article
• Language: English
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00416.2004

1 Department of Cell Biology, Radboud University Nijmegen, Nijmegen; and 2 Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands Submitted 24 August 2004 ; accepted in final form 11 February 2005 We have used normal rat kidney (NRK) fibroblasts as an in vitro model system to study cell transformation. These cells obtain a transformed phenotype upon stimulation with growth-modulating factors such as retinoic acid (RA) or transforming growth factor- (TGF- ). Patch-clamp experiments showed that transformation is paralleled by a profound membrane depolarization from around –70 to –20 mV. This depolarization is caused by a compound in the medium conditioned by transformed NRK cells, which enhances intracellular Ca 2+ levels and thereby activates Ca 2+ -dependent Cl – channels. This compound was identified as prostaglandin F 2 (PGF 2 ) using electrospray ionization mass spectrometry. The active concentration in the medium conditioned by transformed NRK cells as determined using an enzyme immunoassay was 19.7 ± 2.5 nM ( n = 6), compared with 1.5 ± 0.1 nM ( n = 3) conditioned by nontransformed NRK cells. Externally added PGF 2 was able to trigger NRK cells that had grown to density arrest to restart their proliferation. This proliferation was inhibited when the FP receptor (i.e., natural receptor for PGF 2 ) was blocked by AL-8810. RA-induced phenotypic transformation of NRK cells was partially ( 25%) suppressed by AL-8810. Our results demonstrate that PGF 2 acts as an autocrine enhancer and paracrine inducer of cell transformation and suggest that it may play a crucial role in carcinogenesis in general. membrane potential; intracellular calcium; mass spectrometry; FP receptor Address for reprint requests and other correspondence: A. P. R. Theuvenet, Dept. of Cell Biology, Radboud Univ. Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands