Department of Urology, National Defense Medical College, Tokorozawa, Saitama, Japan.
J Urol. 2012 Dec;188(6):2410-8. doi: 10.1016/j.juro.2012.07.108. Epub 2012 Oct 22.
Protein ubiquitination is a novel strategy used to treat malignancies. We investigated whether the histone deacetylase inhibitor vorinostat (Cayman Chemical, Ann Arbor, Michigan) and the proteasome inhibitor bortezomib (LC Laboratories, Woburn, Massachusetts) would synergistically cause the accumulation of ubiquitinated proteins in prostate cancer cells.
LNCaP, PC-3 and DU 145 cells (ATCC™) were treated with vorinostat and/or bortezomib. Cell viability and induction of apoptosis were assessed. In vivo efficacy was evaluated in a murine subcutaneous tumor model using PC-3 cells. The influence of androgen receptor expression on bortezomib efficacy was examined using RNA interference. Changes in the expression of ubiquitinated proteins, cell cycle associated proteins and acetylated histone were evaluated.
Androgen receptor expression seemed to decrease bortezomib activity. PC-3 and DU 145 cells were more susceptible to bortezomib than LNCaP cells and the silencing of androgen receptor expression in LNCaP cells enhanced bortezomib activity. Vorinostat and bortezomib synergistically induced apoptosis, inhibited prostate cancer cell growth and suppressed tumor growth in a murine xenograft model. The combination decreased cyclin D1 and cyclin-dependent kinase 4 expression, and increased p21 expression. The combination synergistically caused the accumulation of ubiquitinated proteins and histone acetylation. This histone acetylation was a consequence of the accumulation of ubiquitinated proteins.
Vorinostat and bortezomib inhibit the growth of prostate cancer cells synergistically by causing ubiquitinated proteins to accumulate in cells. The current study provides a framework for testing the combination in patients with advanced prostate cancer.
蛋白质泛素化是一种用于治疗恶性肿瘤的新策略。我们研究了组蛋白去乙酰化酶抑制剂伏立诺他（密歇根州安阿伯市凯默公司）和蛋白酶体抑制剂硼替佐米（马萨诸塞州沃本市 LC 实验室）是否会协同作用导致前列腺癌细胞中泛素化蛋白的积累。
LNCaP、PC-3 和 DU145 细胞（ATCCTM）用伏立诺他和/或硼替佐米处理。评估细胞活力和诱导凋亡的情况。在使用 PC-3 细胞的小鼠皮下肿瘤模型中评估体内疗效。使用 RNA 干扰研究雄激素受体表达对硼替佐米疗效的影响。评估泛素化蛋白、细胞周期相关蛋白和乙酰化组蛋白的表达变化。
雄激素受体表达似乎降低了硼替佐米的活性。PC-3 和 DU145 细胞比 LNCaP 细胞对硼替佐米更敏感，LNCaP 细胞中雄激素受体表达的沉默增强了硼替佐米的活性。伏立诺他和硼替佐米协同诱导细胞凋亡，抑制前列腺癌细胞生长，并抑制小鼠异种移植模型中的肿瘤生长。联合用药降低了细胞周期蛋白 D1 和细胞周期蛋白依赖性激酶 4 的表达，增加了 p21 的表达。联合用药协同导致泛素化蛋白和组蛋白乙酰化的积累。这种组蛋白乙酰化是泛素化蛋白积累的结果。
伏立诺他和硼替佐米通过使细胞内泛素化蛋白积累，协同抑制前列腺癌细胞的生长。本研究为在晚期前列腺癌患者中测试该联合用药提供了框架。
