Payson R A, Chotani M A, Chiu I M
Department of Internal Medicine and Comprehensive Cancer Center, The Ohio State University, Columbus 43210, USA.
J Steroid Biochem Mol Biol. 1998 Aug;66(3):93-103. doi: 10.1016/s0960-0760(98)00051-x.
FGF-1 mRNA is expressed in the prostate cancer cell lines LNCaP and PC-3 and in the breast carcinoma cell line MDA-MB-231. Levels of FGF-1 mRNA have been shown to be up-regulated by serum, phorbol esters, and combinations of growth factors. It was shown that the major FGF-1 mRNA species expressed following serum stimulation in MDA-MB-231 cells is FGF-1.C. To better understand the potential role of FGF-1 in human prostate and breast cancer, we began an analysis of the cis- and trans-acting elements of one of its promoters required for the serum, PMA, and androgen regulation in breast and prostate cancer cell lines. We show that FGF-1.C steady-state mRNA levels are increased following serum or PMA stimulation of PC-3 cells. Further, we determine the FGF-1.C transcription start site in PC-3 cells. By sequence analysis, we show that consensus AP1, AP2, and Sp1 sites and ARE- and CRE-near consensus elements are present in the immediate 5' region of the FGF-1.C transcription start site. Gel-shift assays show that oligonucleotides containing FGF-1.C AP1, AP2, or Spl sequences form specific DNA-protein complexes with nuclear extracts from PC-3 cells. To determine if these or other cis-acting sequences are responsible for the serum, androgen, or growth factor regulation of FGF-1 expression, fragments of the FGF-1.C promoter region were cloned upstream of the luciferase reporter gene. We show that FGF-1 synergizes with androgen to enhance FGF-1.C transcription in LNCaP cells. We further show that the DNA fragment containing sequence up to 1614 nucleotides upstream of the FGF-1.C transcription start site is sufficient for stimulating promoter activity following serum treatment of MDA-MB-231 cells. Thus, FGF-1.C promoter contains sequences that are important for androgen or serum stimulation in prostate and breast cancer cells.
FGF - 1信使核糖核酸在前列腺癌细胞系LNCaP和PC - 3以及乳腺癌细胞系MDA - MB - 231中表达。已表明FGF - 1信使核糖核酸的水平会被血清、佛波酯和生长因子组合上调。结果显示，MDA - MB - 231细胞在血清刺激后表达的主要FGF - 1信使核糖核酸种类是FGF - 1.C。为了更好地理解FGF - 1在人类前列腺癌和乳腺癌中的潜在作用，我们开始分析其一个启动子的顺式和反式作用元件，该启动子是乳腺癌和前列腺癌细胞系中血清、佛波酯和雄激素调节所必需的。我们发现，PC - 3细胞在血清或佛波酯刺激后，FGF - 1.C的稳态信使核糖核酸水平会升高。此外，我们确定了PC - 3细胞中FGF - 1.C的转录起始位点。通过序列分析，我们发现FGF - 1.C转录起始位点紧邻的5'区域存在共有AP1、AP2和Sp1位点以及ARE - 和CRE - 近共有元件。凝胶迁移试验表明，含有FGF - 1.C AP1、AP2或Spl序列的寡核苷酸与PC - 3细胞的核提取物形成特异性DNA - 蛋白质复合物。为了确定这些或其他顺式作用序列是否负责FGF - 1表达的血清、雄激素或生长因子调节，将FGF - 1.C启动子区域的片段克隆到荧光素酶报告基因的上游。我们发现FGF - 1与雄激素协同作用，增强LNCaP细胞中FGF - 1.C的转录。我们进一步表明，包含FGF - 1.C转录起始位点上游多达1614个核苷酸序列的DNA片段足以在MDA - MB - 231细胞经血清处理后刺激启动子活性。因此，FGF - 1.C启动子包含对前列腺癌和乳腺癌细胞中的雄激素或血清刺激很重要的序列。
