Center for Childhood Cancer, The Research Institute at Nationwide Children's Hospital; Department of Otolaryngology, The Ohio State University College of Medicine, Columbus, Ohio, USA 43205.
Cancer Res. 2013 Jan 15;73(2):792-803. doi: 10.1158/0008-5472.CAN-12-1888. Epub 2012 Nov 14.
Meningiomas constitute about 34% of primary intracranial tumors and are associated with increased mortality in patients with neurofibromatosis type 2 (NF2). To evaluate potential medical therapies for these tumors, we have established a quantifiable orthotopic model for NF2-deficient meningiomas. We showed that telomerase-immortalized Ben-Men-1 benign meningioma cells harbored a single nucleotide deletion in NF2 exon 7 and did not express the NF2 protein, merlin. We also showed that AR-42, a pan-histone deacetylase inhibitor, inhibited proliferation of both Ben-Men-1 and normal meningeal cells by increasing expression of p16(INK4A), p21(CIP1/WAF1), and p27(KIP1). In addition, AR-42 increased proapoptotic Bim expression and decreased anti-apoptotic Bcl(XL) levels. However, AR-42 predominantly arrested Ben-Men-1 cells at G(2)-M whereas it induced cell-cycle arrest at G(1) in meningeal cells. Consistently, AR-42 substantially decreased the levels of cyclin D1, E, and A, and proliferating cell nuclear antigen in meningeal cells while significantly reducing the expression of cyclin B, important for progression through G(2), in Ben-Men-1 cells. In addition, AR-42 decreased Aurora A and B expression. To compare the in vivo efficacies of AR-42 and AR-12, a PDK1 inhibitor, we generated and used luciferase-expressing Ben-Men-1-LucB cells to establish intracranial xenografts that grew over time. While AR-12 treatment moderately slowed tumor growth, AR-42 caused regression of Ben-Men-1-LucB tumors. Importantly, AR-42-treated tumors showed minimal regrowth when xenograft-bearing mice were switched to normal diet. Together, these results suggest that AR-42 is a potential therapy for meningiomas. The differential effect of AR-42 on cell-cycle progression of normal meningeal and meningioma cells may have implications for why AR-42 is well-tolerated while it potently inhibits tumor growth.
脑膜瘤约占原发性颅内肿瘤的 34%,与神经纤维瘤病 2 型 (NF2) 患者的死亡率增加有关。为了评估这些肿瘤的潜在医学治疗方法,我们建立了一种可量化的 NF2 缺陷脑膜瘤原位模型。我们表明,端粒酶永生化的 Ben-Men-1 良性脑膜瘤细胞在 NF2 外显子 7 中存在单一核苷酸缺失,并且不表达 NF2 蛋白 merlin。我们还表明,pan-histone deacetylase 抑制剂 AR-42 通过增加 p16(INK4A)、p21(CIP1/WAF1)和 p27(KIP1)的表达来抑制 Ben-Men-1 和正常脑膜细胞的增殖。此外,AR-42 增加了促凋亡 Bim 的表达,降低了抗凋亡 Bcl(XL)的水平。然而,AR-42 主要将 Ben-Men-1 细胞阻滞在 G2-M 期,而在脑膜细胞中诱导细胞周期阻滞在 G1 期。一致地,AR-42 显著降低了脑膜细胞中环素 D1、E 和 A 以及增殖细胞核抗原的水平,同时显著降低了 Ben-Men-1 细胞中环素 B 的表达,这对于通过 G2 期的进展很重要。此外,AR-42 降低了 Aurora A 和 B 的表达。为了比较 AR-42 和 PDK1 抑制剂 AR-12 的体内疗效,我们生成并使用表达荧光素酶的 Ben-Men-1-LucB 细胞建立了随时间推移而生长的颅内异种移植物。虽然 AR-12 治疗适度减缓了肿瘤生长,但 AR-42 导致 Ben-Men-1-LucB 肿瘤消退。重要的是,当携带异种移植物的小鼠切换到正常饮食时,接受 AR-42 治疗的肿瘤几乎没有再生长。总之,这些结果表明 AR-42 是脑膜瘤的一种潜在治疗方法。AR-42 对正常脑膜和脑膜瘤细胞细胞周期进程的不同影响可能解释了为什么 AR-42 耐受性良好,同时强烈抑制肿瘤生长。