title: Factors regulating pS2-reporter gene expression in MCF-7 breast cancer cell line.
abstract: From the estrogen receptor containing breast cancer cell line MCF-7, several genes were shown to be hormone-inducible. The regulatory components involved in transcriptional regulation of one of them, the pS2 gene, was determined using 1100 bp of its 5'-flanking region to drive the luciferase reporter gene in transiently transfected cells. MCF-7 breast cancer cells expressed 4-times as much luciferase compared to the pancreatic cell line PANG-I, that has ceased endogenous pS2 expression, as well as the colonic cell line CX-1. In MCF-7, pS2-triggered reporter gene expression is greatly enhanced by the tumor promoter TPA, and, to some extend by EGF, demonstrating that pS2 gene expression is due to specific trans-activating factors present in MCF-7, but not in PANG-I or CX-1. Cotransfection by estrogen receptor stimulated expression 10-fold, and combination with TPA had a synergistic effect, inducing expression 100-fold. EGF and estrogen receptor also work synergistically. The enhancing effect was abolished by deleting cis-acting regulatory sequences near the estrogen responsive element, suggesting that the corresponding regulatory factors may physically interact. This luciferase reporter gene assay quickly and conveniently tests the responsiveness to exogenous stimuli and the presence of specific transcription factors in different tumor cell lines.
authors.affiliation: UNIV TUBINGEN,DEPT ANTHROPOL & HUMAN GENET,DIV MOL GENET,D-72074 TUBINGEN,GERMANY.
authors.forename: S
authors.initials: S
authors.lastname: Beck
authors.forename: P
authors.initials: P
authors.lastname: Fegert
authors.forename: P
authors.initials: P
authors.lastname: Gott