title: Diethylstilbestrol-induced immortalization of human endometrial cells: alterations in p53 and estrogen receptor.
abstract: 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 immortalization 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 was dose dependent. DES-treated restrictive temperature variants (RTVs) but not spontaneous RTVs lost the temperature-sensitive phenotype. DES-RTVs also had a shorter doubling time than spontaneous RTVs did. p53 expression 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 to initiation of rodent cells, and our results suggest that estrogen-induced alterations in p53 or other genes that regulate life span could contribute to estrogen-induced initiation.
authors.affiliation: Department of Pathology, University of North Carolina at Chapel Hill, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Rinehart
authors.forename: L H
authors.initials: LH
authors.lastname: Xu
authors.forename: L
authors.initials: L
authors.lastname: Van Le
authors.forename: D G
authors.initials: DG
authors.lastname: Kaufman
mesh_terms: D001483:Base Sequence; D001943:Breast Neoplasms; D002455:Cell Division / Q000187:drug effects; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic; D017931:DNA Primers; D004054:Diethylstilbestrol / Q000494:pharmacology*; D004717:Endometrium / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D016158:Genes, p53 / Q000187:drug effects*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D011960:Receptors, Estrogen / Q000096:biosynthesis* / Q000187:drug effects; D011980:Receptors, Progesterone / Q000096:biosynthesis; D013696:Temperature; D014407:Tumor Cells, Cultured
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D004054:Diethylstilbestrol