Pandya Vrajesh, Glubrecht Darryl, Vos Larissa, Hanson John, Damaraju Sambasivarao, Mackey John, Hugh Judith, Goping Ing Swie
Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
Department of Oncology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
Oncotarget. 2016 May 31;7(22):33272-85. doi: 10.18632/oncotarget.8924.
Breast cancer is the leading cause of cancer-associated deaths in women worldwide. Clinical biomarkers give information on disease progression and identify relevant biological pathways. A confounding factor that uncouples markers from disease outcome is the ability of tumor cells to mutate and evade clinical intervention. Therefore, we focussed on apoptotic genes that modulate tumor regression. Using gene and tissue microarray analyses, we identified an association of Bcl-2 interacting killer (Bik) with poor breast cancer prognosis. Bik prognostic ability was independent of Estrogen Receptor/Progesterone Receptor and Her2 status. Additionally, Bik was independent of anti-apoptotic Bcl-2, Bcl-xL, Mcl-1 and Bcl-w suggesting a complex mechanism of tumor promotion identified by Bik high tumors. Bik also stimulates autophagy, which can contribute to enhanced tumor fitness. We found a significant association between the autophagy marker ATG5 and Bik. Combined high expression level of ATG5 and Bik was a stronger predictor of outcome than either alone. Thus, our study identifies Bik as a novel, independent prognostic biomarker for poor outcomes in breast cancer and suggests that Bik-mediated autophagy contributes to disease recurrence.
乳腺癌是全球女性癌症相关死亡的主要原因。临床生物标志物可提供疾病进展信息并识别相关生物途径。肿瘤细胞发生突变并逃避临床干预的能力是使标志物与疾病结果脱钩的一个混杂因素。因此,我们聚焦于调节肿瘤消退的凋亡基因。通过基因和组织微阵列分析,我们发现Bcl-2相互作用杀手(Bik)与乳腺癌预后不良有关。Bik的预后能力独立于雌激素受体/孕激素受体和Her2状态。此外,Bik独立于抗凋亡蛋白Bcl-2、Bcl-xL、Mcl-1和Bcl-w,这表明Bik高表达的肿瘤存在一种复杂的肿瘤促进机制。Bik还能刺激自噬,这可能有助于提高肿瘤的适应性。我们发现自噬标志物ATG5与Bik之间存在显著关联。ATG5和Bik的联合高表达水平比单独任何一个更能预测预后。因此,我们的研究将Bik确定为乳腺癌预后不良的一种新型独立预后生物标志物,并表明Bik介导的自噬促进疾病复发。