Medical Department 1, University hospital Erlangen-Nuernberg, Ulmenweg 18, 91054 Erlangen, Germany.
World J Gastroenterol. 2011 Aug 21;17(31):3623-9. doi: 10.3748/wjg.v17.i31.3623.
To evaluate the antitumoral effect of combined inhibitors of angiogenesis and histone deacetylases in an experimental rat hepatoma model.
MH7777A hepatoma cells were injected into the liver of male Buffalo rats. After 7 d treatment with the vascular endothelial growth factor receptor antagonist PTK787/ZK222584 (PTK/ZK), the histone deacetylase inhibitor MS-275, tamoxifen (TAM) and/or retinoic acid was initiated (n ≥ 8 animals/group). Natural tumor development was shown in untreated control groups (control 1 with n = 12, control 2 with n = 8). The control groups were initiated at different time points to demonstrate the stability of the hepatoma model. For documentation of possible side effects, we documented any change in body weight, loss of fur and diarrhea. After 21 d treatment, the rats were euthanized. Main target parameters were tumor size and metastasis rate. Additionally, immunohistochemistry for the proliferating cell nuclear antigen (PCNA) and TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay were performed.
The control groups developed large tumor nodules with extrahepatic tumor burden in the lung and abdominal organs (control 1: 6.18 cm(3) ± 4.14 cm(3) and control 2: 8.0 cm(3) ± 4.44 cm(3) 28 d after tumor cell injection). The tumor volume did not differ significantly in the control groups (P = 0.13). As single agents MS-275 and PTK/ZK reduced tumor volume by 58.6% ± 2.6% and 48.7% ± 3.2% vs control group 1, which was significant only for MS-275 (P = 0.025). The combination of MS-275 and PTK/ZK induced a nearly complete and highly significant tumor shrinkage by 90.3% ± 1% (P = 0.005). Addition of TAM showed no further efficacy, while quadruple therapy with retinoic acid increased antitumoral efficacy (tumor reduction by 93 ± 1%) and side effects. PCNA positive cells were not significantly reduced by the single agents, while dual therapy (MS-275 and PTK/ZK) and quadruple therapy reduced the PCNA-positive cell fraction significantly by 9.1 and 20.6% vs control 1 (P < 0.05). The number of TUNEL-positive cells, markers for ongoing apoptosis, was increased significantly by the single agents (control 1: 6.9%, PTK/ZK: 11.4%, MS-275: 12.2% with P < 0.05 vs control 1). The fraction of TUNEL-positive cells was upregulated highly significantly by dual therapy (18.4%) and quadruple therapy (24.8%, P < 0.01 vs control 1). For the proliferating (PCNA positive) and apoptotic cell fraction, quadruple therapy was significantly superior to dual therapy (P = 0.01).
Combined PTK/ZK and MS-275 were highly effective in this hepatoma model. Quadruple therapy enhanced the effects microscopically, but not macroscopically. These results should be investigated further.
评估血管生成和组蛋白去乙酰化酶双重抑制剂在实验性大鼠肝癌模型中的抗肿瘤作用。
将 MH7777A 肝癌细胞注入雄性水牛大鼠肝脏。在第 7 天用血管内皮生长因子受体拮抗剂 PTK787/ZK222584（PTK/ZK）治疗后，开始给予组蛋白去乙酰化酶抑制剂 MS-275、他莫昔芬（TAM）和/或维甲酸治疗（每组 n = 8 只动物）。未治疗的对照组（对照组 1，n = 12；对照组 2，n = 8）显示自然肿瘤发展。对照组在不同时间点开始启动，以证明肝癌模型的稳定性。为了记录可能的副作用，我们记录了体重变化、掉毛和腹泻等任何变化。治疗 21 天后，处死大鼠。主要目标参数为肿瘤大小和转移率。此外，还进行了增殖细胞核抗原（PCNA）的免疫组织化学和末端转移酶介导的 dUTP-生物素缺口末端标记（TUNEL）检测。
对照组在肿瘤细胞注射后 28 天形成了具有肝外肿瘤负担的大肿瘤结节（对照组 1：6.18cm³±4.14cm³，对照组 2：8.0cm³±4.44cm³）。对照组之间的肿瘤体积没有显著差异（P = 0.13）。作为单一药物，MS-275 和 PTK/ZK 使肿瘤体积分别减少了 58.6%±2.6%和 48.7%±3.2%，与对照组 1相比，MS-275 的效果显著（P = 0.025）。MS-275 和 PTK/ZK 的联合治疗导致肿瘤几乎完全和显著缩小 90.3%±1%（P = 0.005）。添加 TAM 没有进一步的疗效，而添加维甲酸的四联疗法增加了抗肿瘤疗效（肿瘤缩小 93±1%）和副作用。单一药物对 PCNA 阳性细胞没有显著减少，而双重治疗（MS-275 和 PTK/ZK）和四联治疗使 PCNA 阳性细胞分数分别显著减少 9.1%和 20.6%，与对照组 1相比（P < 0.05）。正在凋亡的 TUNEL 阳性细胞标志物的数量显著增加，与对照组 1相比，单一药物（对照组 1：6.9%，PTK/ZK：11.4%，MS-275：12.2%）（P < 0.05）。双重治疗（18.4%）和四联治疗（24.8%）使 TUNEL 阳性细胞的比例显著上调（P < 0.01 与对照组 1 相比）。对于增殖（PCNA 阳性）和凋亡细胞比例，四联疗法明显优于双重疗法（P = 0.01）。
在该肝癌模型中，PTK/ZK 和 MS-275 的联合治疗非常有效。四联疗法在显微镜下增强了效果，但在宏观上没有增强。这些结果应进一步研究。
