肝母细胞瘤分子标志物检测、异体移植模型建立及靶向治疗

Activation of Hippo and Wnt pathway effectors in Chinese hepatoblastomas and molecular targeting in a patient-derived xenograft model

目的检测中国肝母细胞瘤(HB)样本中Hippo及Wnt抑癌信号通路活化状态、构建肝母细胞瘤小鼠异体移植模型(PDX),并在此基础上检测候选药物疗效。方法收集在复旦大学附属儿科医院病理确诊为HB患儿的肿瘤及瘤旁肝脏组织,通过免疫组化染色(IHC)检测组织中YAP和β-catenin(分别反映Hippo及Wnt通路活化状态)表达及亚细胞定位情况;利用HB细胞系HuH6,检测TNKS1/2抑制剂(XAV939)对YAP和β-catenin的抑制作用;构建HB小鼠PDX,并检测XAV939与其他候选药物对HB PDX生长的抑制效应。结果在本组病例中,YAP和β-catenin在HB肿瘤组织中的表达较瘤旁组织显著上调(P<0.05)。在HuH6细胞系中,XAV939能够通过稳定AMOT和AXIN1/2进而抑制YAP和β-catenin的活性。在HB PDX动物实验中,顺铂及顺铂+XAV939可以显著抑制肿瘤的生长且作用相似,而XAV939单独作用于PDX时,未检测到明显的肿瘤抑制作用;相反,成人肝癌药物索拉菲尼能够显著抑制HB PDX的生长。结论YAP和β-catenin在中国HB样本中同时被异常激活。然而在HB PDX模型中,相较于顺铂及索拉菲尼,TNKS1/2抑制剂未能显示明显的肿瘤抑制效应。因此,在HB中靶向Hippo和Wnt通路还需要更深入的研究。

Objective To determine status of both Hippo and Wnt tumor suppressor pathways in Chinese hepatoblastoma(HB) specimens, and to test anti-tumor effect of selected drugs in a HB PDX model. Methods Immunohistochemistry(IHC) staining of 20 HB specimens with paired adjacent normal tissues were performed to detect the status of YAP and β-catenin. Cell experiments using HB cells(Huh6) were performed to test the effect of XAV939, a TNKS1/2 inhibitor, on YAP and β-catenin activity. A HB patient-derived xenograft(PDX) model was established to test the effect of XAV939 and other drugs on tumor development. Results Concurrent activation of YAP and β-catenin were observed in Chinese HB patient samples. XAV939 inactivated YAP and β-catenin by accumulating AMOT and AXIN1/2 in Huh6 cells. While Cisplatin and Sorafenib had obvious inhibition effect on PDX tumor growth, XAV939 alone had no obvious effect, and the combination of XAV939 with Cisplatin showed similar effect as Cisplatin single therapy. Conclusion While YAP and β-catenin were activated in Chinese HB patients, XAV939 did not show a significant inhibition on the growth of tumor in a HB PDX model as Cisplatin did. Further work is needed to explore the role of Hippo and Wnt pathways in HB development and to target these two pathways molecularly.