Limonta P, Dondi D, Moretti R M, Fermo D, Garattini E, Motta M
Department of Endocrinology, University of Milano, Italy.
J Clin Endocrinol Metab. 1993 Mar;76(3):797-800. doi: 10.1210/jcem.76.3.8445038.
Recent evidence suggests that LHRH or a LHRH-like peptide might be produced by human prostatic tumor cells. To test this hypothesis, we have studied whether a mRNA for LHRH is expressed in the human prostatic cancer cell line LNCaP, by means of the RT-PCR (reverse transcription-polymerase chain reaction) technique. For these experiments, mRNA was extracted from LNCaP cells, from rat hypothalami and from rat pituitaries, reverse transcribed to cDNA and amplified via the PCR utilizing a pair of oligonucleotide primers complementary to the LHRH cDNA. Following gel electrophoresis, a band of the expected size of 228 base pairs was found in LNCaP cells as well as in the rat hypothalamus, but not in the rat anterior pituitary. This 228 base pair band from LNCaP cells and from the rat hypothalamus specifically hybridized to a 32P-labeled LHRH oligonucleotide probe. The cDNA band obtained from LNCaP cells was subcloned into a plasmid vector, and the analysis of its sequence showed a complete match with the authentic human placental LHRH cDNA. These observations clearly demonstrate that a mRNA for LHRH is expressed in human prostatic cancer cells, and suggest that LHRH or a LHRH-like peptide may be produced by these cells. To test the hypothesis whether this material might act as a local growth regulating factor on tumor cell proliferation, LNCaP cells, grown in a steroid-free medium, were treated daily with a potent LHRH antagonist. After 9, 12 and 15 days, the treatment resulted in a significant increase of tumor cell proliferation. These data clearly suggest that the LHRH mRNA expressed in LNCaP cells is possibly translated into LHRH or a LHRH-like peptide which probably functions as a local growth inhibitory factor on prostatic tumor cell proliferation, by acting on LHRH receptors.
最近有证据表明，人前列腺肿瘤细胞可能产生促黄体生成素释放激素（LHRH）或一种类似LHRH的肽。为了验证这一假设，我们通过逆转录聚合酶链反应（RT-PCR）技术研究了LHRH的信使核糖核酸（mRNA）是否在人前列腺癌细胞系LNCaP中表达。在这些实验中，从LNCaP细胞、大鼠下丘脑和大鼠垂体中提取mRNA，逆转录成互补脱氧核糖核酸（cDNA），并使用一对与LHRH cDNA互补的寡核苷酸引物通过聚合酶链反应进行扩增。凝胶电泳后，在LNCaP细胞以及大鼠下丘脑中发现了一条预期大小为228个碱基对的条带，但在大鼠垂体前叶中未发现。来自LNCaP细胞和大鼠下丘脑的这条228个碱基对的条带与一个用32P标记的LHRH寡核苷酸探针发生特异性杂交。从LNCaP细胞获得的cDNA条带被亚克隆到一个质粒载体中，对其序列的分析表明它与真正的人胎盘LHRH cDNA完全匹配。这些观察结果清楚地表明，LHRH的mRNA在人前列腺癌细胞中表达，并提示这些细胞可能产生LHRH或一种类似LHRH的肽。为了验证这种物质是否可能作为一种局部生长调节因子影响肿瘤细胞增殖的假设，在无类固醇培养基中生长的LNCaP细胞每天用一种强效LHRH拮抗剂处理。9天、12天和15天后，这种处理导致肿瘤细胞增殖显著增加。这些数据清楚地表明，在LNCaP细胞中表达的LHRH mRNA可能被翻译成LHRH或一种类似LHRH的肽，其可能通过作用于LHRH受体而作为一种局部生长抑制因子对前列腺肿瘤细胞增殖发挥作用。
