Ding Zhihu, Shi Chaomei, Jiang Lan, Tolstykh Tatiana, Cao Hui, Bangari Dinesh S, Ryan Susan, Levit Mikhail, Jin Taiguang, Mamaat Karl, Yu Qunyan, Qu Hui, Hopke Joern, Cindhuchao May, Hoffmann Dietmar, Sun Fangxian, Helms Mike W, Jahn-Hofmann Kerstin, Scheidler Sabine, Schweizer Liang, Fang Douglas D, Pollard Jack, Winter Christopher, Wiederschain Dmitri
Sanofi Oncology Therapeutic Area, Cambridge, MA, USA.
Sanofi Translational In Vivo Models, Framingham, MA, USA.
Oncotarget. 2017 Sep 28;8(70):114526-114539. doi: 10.18632/oncotarget.21298. eCollection 2017 Dec 29.
Hepatocellular carcinoma (HCC) represents a serious public health challenge with few therapeutic options available to cancer patients.Wnt/β-catenin pathway is thought to play a significant role in HCC pathogenesis. In this study, we confirmed high frequency of CTNNB1 (β-catenin) mutations in two independent cohorts of HCC patients and demonstrated significant upregulation of β-catenin protein in the overwhelming majority of HCC patient samples, patient-derived xenografts (PDX) and established cell lines. Using genetic tools validated for target specificity through phenotypic rescue experiments, we went on to investigate oncogenic dependency on β-catenin in an extensive collection of human HCC cells lines. Our results demonstrate that dependency on β-catenin generally tracks with its activation status. HCC cell lines that harbored activating mutations in CTNNB1 or displayed elevated levels of non-phosphorylated (active) β-catenin were significantly more sensitive to β-catenin siRNA treatment than cell lines with wild-type CTNNB1 and lower active β-catenin. Finally, significant therapeutic benefit of β-catenin knock-down was demonstrated in established HCC tumor xenografts using doxycycline-inducible shRNA system. β-catenin downregulation and tumor growth inhibition was associated with reduction in AXIN2, direct transcriptional target of β-catenin, and decreased cancer cell proliferation as measured by Ki67 staining. Taken together, our data highlight fundamental importance of aberrant β-catenin signaling in the maintenance of oncogenic phenotype in HCC.
肝细胞癌（HCC）是一项严峻的公共卫生挑战，癌症患者可用的治疗选择寥寥无几。Wnt/β-连环蛋白信号通路被认为在HCC发病机制中起重要作用。在本研究中，我们在两个独立的HCC患者队列中证实了CTNNB1（β-连环蛋白）突变的高频率，并在绝大多数HCC患者样本、患者来源的异种移植瘤（PDX）和已建立的细胞系中证明了β-连环蛋白蛋白的显著上调。通过表型拯救实验验证了针对靶标特异性的遗传工具，我们接着在大量人类HCC细胞系中研究了对β-连环蛋白的致癌依赖性。我们的结果表明，对β-连环蛋白的依赖性通常与其激活状态相关。在CTNNB1中携带激活突变或显示非磷酸化（活性）β-连环蛋白水平升高的HCC细胞系，比具有野生型CTNNB1和较低活性β-连环蛋白的细胞系对β-连环蛋白siRNA治疗明显更敏感。最后，使用强力霉素诱导的shRNA系统在已建立的HCC肿瘤异种移植瘤中证明了β-连环蛋白敲低具有显著的治疗益处。β-连环蛋白下调和肿瘤生长抑制与AXIN2（β-连环蛋白的直接转录靶标）的减少以及通过Ki67染色测量的癌细胞增殖减少有关。综上所述，我们的数据突出了异常β-连环蛋白信号在维持HCC致癌表型中的根本重要性。
