Department of Anatomy, Chang Gung University, Kwei-Shan, Taiwan, Republic of China.
J Urol. 2010 Nov;184(5):2158-64. doi: 10.1016/j.juro.2010.06.093. Epub 2010 Sep 17.
While cardiac glycosides are the mainstay of congestive heart failure treatment, early studies showed that pharmacological doses of cardiac glycosides inhibited prostate cancer cell line proliferation. We evaluated the mechanisms of cardiac glycosides, including digoxin, digitoxin and ouabain (Sigma®), on prostate specific antigen gene expression in vitro.
We cultured LNCaP cells (ATCC®) and used them to determine the effect of cardiac glycosides on prostate derived Ets factor and prostate specific antigen expression. We determined prostate derived Ets factor and prostate specific antigen expression by reverse transcription-polymerase chain reaction, immunoblot, transient gene expression assay or enzyme-linked immunosorbent assay.
Noncytotoxic doses (100 nM) of cardiac glycosides for 24 hours inhibited prostate specific antigen secretion by LNCaP cells. Reverse transcriptase-polymerase chain reaction and immunoblot revealed that cardiac glycosides significantly down-regulated prostate specific antigen and prostate derived Ets factor expression. Transient gene expression assays showed that prostate derived Ets factor over expression enhanced prostate specific antigen promoter activity. However, prostate specific antigen and prostate derived Ets factor gene promoter activity was attenuated when LNCaP cells were treated with 100 nM cardiac glycosides. When LNCaP cells were treated with 25 nM digitoxin or digoxin for 60 hours, prostate specific antigen secretion decreased by 30%.
Results suggest that cardiac glycoside inhibition of prostate specific antigen gene expression may be caused by the down-regulation of prostate derived Ets factor gene expression. When cells were chronically treated with digoxin or digitoxin at concentrations close to or at therapeutic plasma levels, prostate specific antigen secretion decreased. This phenomenon merits further study to determine whether it occurs in men on cardiac glycoside therapy.
虽然强心苷是治疗充血性心力衰竭的主要药物，但早期的研究表明，药理剂量的强心苷能抑制前列腺癌细胞系的增殖。我们评估了强心苷（包括地高辛、洋地黄毒苷和哇巴因，Sigma®）在体外对前列腺特异性抗原基因表达的作用机制。
我们培养 LNCaP 细胞（ATCC®），并使用它们来确定强心苷对前列腺衍生的 Ets 因子和前列腺特异性抗原表达的影响。我们通过逆转录-聚合酶链反应、免疫印迹、瞬时基因表达测定或酶联免疫吸附试验来确定前列腺衍生的 Ets 因子和前列腺特异性抗原的表达。
非细胞毒性剂量（100 nM）的强心苷作用 24 小时可抑制 LNCaP 细胞前列腺特异性抗原的分泌。逆转录-聚合酶链反应和免疫印迹显示，强心苷显著下调前列腺特异性抗原和前列腺衍生的 Ets 因子的表达。瞬时基因表达试验表明，前列腺衍生的 Ets 因子过表达增强了前列腺特异性抗原启动子的活性。然而，当 LNCaP 细胞用 100 nM 的强心苷处理时，前列腺特异性抗原和前列腺衍生的 Ets 因子基因启动子的活性减弱。当 LNCaP 细胞用 25 nM 的地高辛或 digoxin 处理 60 小时时，前列腺特异性抗原的分泌减少了 30%。
结果表明，强心苷抑制前列腺特异性抗原基因表达可能是由于前列腺衍生的 Ets 因子基因表达下调所致。当细胞以接近或治疗血浆水平的浓度长期用地高辛或 digoxin 处理时，前列腺特异性抗原的分泌减少。这种现象值得进一步研究，以确定它是否发生在接受强心苷治疗的男性中。
