Diethylstilbestrol-induced immortalization of human endometrial cells: Alterations in p53 and estrogen receptor

✍ Scribed by Clifford A. Rinehart; Li-hui Xu; Linda Van Le; David G. Kaufman

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 959 KB
• Volume: 15
• Category: Article
• ISSN: 0899-1987
• DOI: 10.1002/(sici)1098-2744(199602)15:2<115::aid-mc4>3.0.co;2-i

✦ Synopsis

carcinogenesis is a process requiring multiple steps. Immortalization is one step in this process and may be rate limiting. To ,further our understanding of estrogen-induced carcinogenesis, we evaluated diethylstilbestrol (DES)-induced irnmortalization of human endometrial stromal cells. This was achieved by assessing at the restrictive temperature the colony-forming efficiency of cells that were conditionally immortalized with a temperature-sensitive simian virus 40 large T antigen. Treatment with DES for 1 wk did not increase the immortalization frequency; however, cultures that were treated for 20 wk had a twofold increase in immortalization frequency, and continued treatment for a total of 44 wk produced a threefold increase in immortalization frequency that vvas dose dependent. DES-treated restrictive temperature variants (RWs) but not spontaneous RTVs lost the temperature-sensitive phenotype. DES-RTVs also had a shorter doubling time than spontaneous RTVs did. p53 exlpression was increased in DES-RTVs, and its localization within the cell was altered. Conversely, expression of the estrogen receptor was decreased in DES-immortalized cells. These changes in gene expression often occur in estrogen-related malignancies, and our results are consistent with a causal role for estrogens in these p53 and the estrogen receptor alterations. Immortalization of human cells may be analogous t o initiation of rodlent cells, and our results suggest that estrogen-induced alterations in p 5 3 or other genes that regulate life span could contribute t o estrogen-induced initiation.