Abstract
We have recently demonstrated that exposure of MCF7 cells to antiestrogens in vitro results in both accumulation of IGF-BP3 in media and reduced mitogenic responsivity to IGFs (Cancer Res. 53:5193-5198). We show here that MCF7 cell proliferation in steroid-stripped, serum containing media is significantly attenuated by rhIGF-BP3 (p<0.05), with a maximal 40% inhibition of serum stimulated growth achieved by 6.25nM IGF-BP3. 10 −10M estradiol (E 2) significantly stimulated MCF7 proliferation, and co-incubation of estrogen containing cultures with 50nM IGF-BP3 resulted in significant attenuation of the estrogen-stimulated proliferation ([ 3H]thymidine incorporation: E 2, 147±18% of control; E 2 + IGF-BP3, 111±18% of control, p<0.05). These results demonstrate antagonism of steroid stimulated proliferation by an IGF binding protein and are compatible with the hypothesis that antiestrogen-induced accumulation of IGF-BP3 in the conditioned media of MCF7 cells contributes to the cytostatic action of these drugs.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Biochemical and Biophysical Research Communications
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
