Takeuchi Hisashi, Mmeje Chinedu O, Jinesh Goodwin G, Taoka Rikiya, Kamat Ashish M
Department of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Oncol Rep. 2015 Nov;34(5):2738-44. doi: 10.3892/or.2015.4220. Epub 2015 Aug 21.
Bladder cancer is a common malignancy for which regional or metastatic disease is identified at diagnosis. The aim of this study was to determine whether tamoxifen (Tam), an estrogen receptor (ER) antagonist, can sensitize bladder cancer cell lines to gemcitabine (Gem) chemotherapy. ERα and ERβ protein levels were determined in each cell line using western blot analysis. The TCC-Sup, 5637, and RT4 bladder cancer cells were exposed to various concentrations and regimens of Tam or Gem alone or in combination. Cell viability and apoptosis were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and propidium iodide followed by flow cytometry. Apoptosis was then evaluated by western blot analysis. Treated TCC-Sup cells were subjected to soft agar colony formation assay to determine the cellular transformation. Western blot analysis results revealed ER expression in the three cell lines. TCC-Sup and 5637 cells treated with a combination of Tam and Gem had lower cell viabilities than those treated with Tam or Gem alone for 72 h in TCC-Sup and 5637. Compared with the other treatments, sequential Gem followed by Tam (Gem→Tam) treatment caused the largest increase in DNA fragmentation at 72 h in TCC-Sup cells. Western blot analysis results revealed that this sequential Gem→Tam treatment increased poly(ADP-ribose) polymerase cleavage in TCC-Sup cells. Sequential Gem→Tam inhibited the cell transformation in TCC-Sup cells. In conclusion, sequential Gem→Tam enhanced the cytotoxicity of Gem in vitro. This regimen be useful to enhance the efficacy of Gem in bladder cancer. However, future in vivo studies are required to verify the results.
膀胱癌是一种常见的恶性肿瘤，在诊断时可发现局部或转移性疾病。本研究的目的是确定雌激素受体（ER）拮抗剂他莫昔芬（Tam）是否能使膀胱癌细胞系对吉西他滨（Gem）化疗敏感。使用蛋白质印迹分析确定每个细胞系中的ERα和ERβ蛋白水平。将TCC-Sup、5637和RT4膀胱癌细胞单独或联合暴露于不同浓度和方案的Tam或Gem。通过3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐测定法和碘化丙啶随后进行流式细胞术评估细胞活力和凋亡。然后通过蛋白质印迹分析评估凋亡。对处理过的TCC-Sup细胞进行软琼脂集落形成试验以确定细胞转化。蛋白质印迹分析结果显示这三种细胞系中均有ER表达。在TCC-Sup和5637中，联合使用Tam和Gem处理的TCC-Sup和5637细胞在72小时时的细胞活力低于单独使用Tam或Gem处理的细胞。与其他处理相比，先使用Gem后使用Tam（Gem→Tam）的序贯处理在72小时时导致TCC-Sup细胞中DNA片段化增加最多。蛋白质印迹分析结果显示，这种Gem→Tam序贯处理增加了TCC-Sup细胞中聚（ADP-核糖）聚合酶的切割。Gem→Tam序贯处理抑制了TCC-Sup细胞中的细胞转化。总之，Gem→Tam序贯处理增强了Gem在体外的细胞毒性。该方案可能有助于提高Gem在膀胱癌中的疗效。然而，需要未来的体内研究来验证结果。
