Department of Paediatric Surgery and Paediatric Urology, University Children's Hospital, Hoppe-Seyler-Strasse 1, D-72076 Tübingen, Germany.
BMC Cancer. 2011 Aug 19;11:362. doi: 10.1186/1471-2407-11-362.
The primary goal of current chemotherapy in hepatoblastoma (HB) is reduction of tumour volume and vitality to enable complete surgical resection and reduce risk of recurrence or metastatic disease. Drug resistance remains a major challenge for HB treatment. In some malignancies inhibition of anti-apoptotic pathways using small BH3 mimetic molecules like ABT-737 shows synergistic effects in combination with cystotoxic agents in vitro. Now we analysed toxicology and synergistic effects of this approach in HB cells and HB xenografts.
Viability was monitored in HB cells (HUH6 and HepT1) and fibroblasts treated with paclitaxel, ABT-737 and a combination of both in a MTT assay. HUH6 xenotransplants in NOD/LtSz-scid IL2Rγnull mice (NSG) were treated accordingly. Tumour volume and body weight were monitored. Xenografted tumours were analysed by histology and immunohistochemistry (Ki-67 and TUNEL assay).
ABT-737 reduced viability in HUH6 and HepT1 cells cultures at concentrations above 1 μM and also enhanced the cytotoxic effect of paclitaxel when used in combination. Thereby paclitaxel could be reduced tenfold to achieve similar reduction of viability of tumour cells. In contrast no toxicity in fibroblasts was observed at the same regiments. Subcutaneous HB (HUH6) treated with paclitaxel (12 mg/kg body weight, n = 7) led to delayed tumour growth in the beginning of the experiment. However, tumour volume was similar to controls (n = 5) at day 25. Combination treatment with paclitaxel and ABT-737 (100 mg/kg, n = 8) revealed significantly 10 fold lower relative tumour volumes compared to control and paclitaxel groups. Paclitaxel dependent toxicity was observed in this mice strain.
Our results demonstrate enhancement of chemotherapy by using modulators of apoptosis. Further analyses should include improved pharmacological formulations of paclitaxel and BH3 mimetics in order to reduce toxicological effects. Sensitising HB to apoptosis may also render resistant HB susceptible to established chemotherapy regimens.
目前肝癌（HB）化疗的主要目标是降低肿瘤体积和活力，以实现完全手术切除，并降低复发或转移性疾病的风险。耐药性仍然是 HB 治疗的主要挑战。在一些恶性肿瘤中，使用小分子 BH3 模拟物如 ABT-737 抑制抗凋亡途径，在体外与细胞毒性药物联合使用时显示出协同作用。现在我们分析了这种方法在 HB 细胞和 HB 异种移植中的毒理学和协同作用。
用 MTT 法检测紫杉醇、ABT-737 及两者联合处理 HB 细胞（HUH6 和 HepT1）和成纤维细胞的活力。用相应方法处理 NOD/LtSz-scid IL2Rγnull 小鼠（NSG）中的 HUH6 异种移植瘤。监测肿瘤体积和体重。用组织学和免疫组化（Ki-67 和 TUNEL 检测）分析异种移植瘤。
ABT-737 在浓度高于 1 μM 时降低 HUH6 和 HepT1 细胞培养物的活力，并且与紫杉醇联合使用时增强其细胞毒性作用。因此，紫杉醇的用量可以减少十倍，而肿瘤细胞活力的降低程度相似。相反，在相同的条件下，成纤维细胞没有毒性。用紫杉醇（12 mg/kg 体重，n = 7）处理皮下 HB（HUH6），在实验开始时导致肿瘤生长延迟。然而，在第 25 天，肿瘤体积与对照组（n = 5）相似。与对照组和紫杉醇组相比，紫杉醇和 ABT-737 联合治疗（100 mg/kg，n = 8）的相对肿瘤体积显著降低 10 倍。在这种小鼠品系中观察到紫杉醇依赖的毒性。
我们的结果表明，使用凋亡调节剂增强化疗效果。进一步的分析应包括改进紫杉醇和 BH3 模拟物的药理学配方，以降低毒理学效应。使 HB 对凋亡敏感也可能使耐药 HB 对现有化疗方案敏感。
