Thompson T A, Lewis J M, Dejneka N S, Severs W B, Polavarapu R, Billingsley M L
Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA, USA.
J Pharmacol Exp Ther. 1996 Mar;276(3):1201-16.
Immortalized cell lines and primary neuronal cultures were used to characterize the selective toxicity of trimethyltin (TMT),triethyltin (TET) and tributyltin (TBT). TBT and TET were cytotoxic at similar concentrations in the immortalized cell lines tested; the 50% toxic concentration (TC50) was 1 to 11 microM. In contrast, immortalized cell lines varied considerably in their sensitivity to TMT, with sensitive cell lines (neuroblastomas, T-, B-cell lines) showing TC50 values of 2 to 8 microM, whereas insensitive cells (NIH-3T3 fibroblast, HTB-14 glioma, TC-7 kidney cells) had TC 50 values > 100 microM. Primary neuronal cell cultures were very sensitive to organotins (TC50 values, 1-10nM), and showed patterns of selective toxicity with respect to neuronal and glial cells. Because organotin toxicity evolves over 24 to 48 hr. we determined whether these compounds induced apoptosis in primary cultures. TMT increased (P < .05) the fraction of apoptotic cells 6 and 12 hr after treatment with TMT at TC50 concentrations. Prior studies suggested that a protein, stannin, was localized in cells sensitive to organotins. Stannin was expressed in several TMT-sensitive cell lines (PC12, T, B cells) and in primary neurons in culture. Stannin was absent in the resistant HTB-14 glioma cell line. The role of stannin in mediating TMT toxicity in primary cultures was investigated by blocking stannin expression with specific antisense oligonucleotides. Treatment of primary cultures with antisense oligonucleotides for 48 hr before and during TMT treatment significantly protected neurons from the neurotoxic and apoptotic effects of TMT. This effect was not observed with scrambled oligonucleotide controls. Thus, TMT may induce apoptosis in sensitive cells, which is partly mediated by stannin. Based on the available data we conclude that stannin expression is necessary, but not sufficient for TMT toxicity.
使用永生化细胞系和原代神经元培养物来表征三甲基锡（TMT）、三乙基锡（TET）和三丁基锡（TBT）的选择性毒性。在测试的永生化细胞系中，TBT和TET在相似浓度下具有细胞毒性；50%毒性浓度（TC50）为1至11微摩尔。相比之下，永生化细胞系对TMT的敏感性差异很大，敏感细胞系（神经母细胞瘤、T细胞、B细胞系）的TC50值为2至8微摩尔，而不敏感细胞（NIH-3T3成纤维细胞、HTB-14胶质瘤细胞、TC-7肾细胞）的TC50值>100微摩尔。原代神经元细胞培养物对有机锡非常敏感（TC50值为1-10纳摩尔），并且在神经元和神经胶质细胞方面表现出选择性毒性模式。由于有机锡毒性在24至48小时内逐渐显现。我们确定了这些化合物是否在原代培养物中诱导细胞凋亡。在TC50浓度下用TMT处理6小时和12小时后，TMT增加了（P<.05）凋亡细胞的比例。先前的研究表明，一种名为锡蛋白的蛋白质定位于对有机锡敏感的细胞中。锡蛋白在几种对TMT敏感的细胞系（PC12、T细胞、B细胞）和培养的原代神经元中表达。在抗性HTB-14胶质瘤细胞系中不存在锡蛋白。通过用特异性反义寡核苷酸阻断锡蛋白表达，研究了锡蛋白在介导原代培养物中TMT毒性中的作用。在TMT处理之前和期间，用反义寡核苷酸处理原代培养物48小时，可显著保护神经元免受TMT的神经毒性和凋亡作用。在乱序寡核苷酸对照中未观察到这种效果。因此，TMT可能在敏感细胞中诱导细胞凋亡，这部分是由锡蛋白介导的。根据现有数据，我们得出结论，锡蛋白的表达对于TMT毒性是必要的，但不是充分的。
