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Updated: Aug 16, 2026

Analysis of Combinatorial miRNA Treatments to Regulate Cell Cycle and Angiogenesis
Published on: March 30, 2019
Endothelial p21(WAF1/CiP1) cell cycle inhibitor is down-regulated in breast cancer
T Vrekoussis1, E N Stathopoulos, M Kafousi
1Department of General Surgery, University Hospital and Medical School University of Crete, Heraklion, Greece.
Background:
Tumor angiogenesis is considered a multi-pathway process, while p21(WAF1/CiP1) is a CDK inhibitor involved in cell division and survivaL Herein the tumor environment effect on endothelial p21(WAF1/Cip1) expression is examined.
Materials And Methods:
The EA.hy 926 endothelial cell line and tumor-conditioned medium (TCM) from the MDA-MB-468 breast cancer cell line were used. Endothelial cells grown alone and in TCM were immunostained for p21(WAF1/Cip1) and analyzed by RT-PCR Forty-four cases of breast cancer and forty-three cases of normal breast tissue were immunostained for p21(WAF1/Cip1).
Results:
Endothelial p21(WAF1/Cip1) is transcriptionally down-regulated under the influence of TCM. Moreover, it seems that breast cancer tumor endothelium does not express p21(WAF1/Cip1).
Conclusion:
P21(WAF1/Cip1) plays a major role in angiogenesis, since tumor cells seem to down-regulate endothelial p21(WAF1/Cip1), compared to endothelial cells grown in serum-free medium. The verification of the tissue culture experiment results by immunohistochemistry on tissue sections indicates p21(WAF1/Cip1) as a target of modern molecular therapy.
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