Identification of a stemness-related gene panel associated with BET inhibition in triple negative breast cancer
Identification of a stemness-related gene panel associated with BET inhibition in triple negative breast cancer
复制标题
DOI：
10.1007/s13402-020-00497-6
复制
发表时间：
2020-06-01
影响因子：
6.6
通讯作者：
Maria Galan-Moya, Eva
中科院分区：
文献类型：
--
作者：
Serrano-Oviedo, Leticia;Nuncia-Cantarero, Miriam;Maria Galan-Moya, Eva
目的三阴性乳腺癌(TNBCs)富含具有干细胞样特征的细胞，即肿瘤干细胞(CSCs)，是肿瘤进展的基础。因此，靶向干细胞可能是一种有趣的治疗方法。表观遗传机制是维持茎的表型的关键。溴结构域和末端外结构域(BET)表观遗传阅读器家族成员正在成为癌症治疗的新靶点，并已在乳腺癌中显示出临床前效果。在这里，我们的目的是评估BET抑制剂JQ1对TNBC茎的影响。方法对体外培养的JQ1暴露的TNBC细胞进行转录、功能注释和qRT-PCR研究。所获得的结果在球体和球体来源的肿瘤中得到证实。此外，通过极限稀释法、二、三级肿瘤球体形成、基质侵袭、免疫荧光和流式细胞仪检测，评价JQ1对CSC特性的影响。对于临床结果分析，使用了在线工具Kaplan-Meier绘图仪和综合反应数据库。结果我们发现JQ1对两种TNBC来源的细胞株MDA-MB-231和BT549的干性相关基因的表达有影响。在这些变化中，CD44抗原/CD24抗原(CD44/CD24)比率和乙醛脱氢酶1家族成员A1(ALDH1A1)的表达水平都被发现被JQ1降低，即这两个经典的茎性标记。使用一个有效的球体模型来模拟CSCs的内在特征，我们发现JQ1降低了表面CD44的表达，抑制了自我更新和侵袭，并诱导G0/G1细胞周期停滞，从而改变了干细胞的表型。我们还发现四个已识别的干性基因，缝隙连接蛋白Alpha1(GJA1)，CD24，上皮黏附分子(EpCAM)和SRY相关的HMG-box基因9(SOX9)与TNBC患者的预后较差有关。另外两个与干性相关的基因，即三磷酸腺苷结合盒G成员2(ABCG2)和RUNX2的表达被JQ1下调，这预示着TNBC患者对化疗的低反应性，这支持RUNX2作为TNBC化疗反应的潜在预测标志。结论我们确定了一个与JQ1相关的干性相关基因小组，并描述了该抑制物如何改变TNBC的干性景观。因此，我们提出了JQ1作为干基靶向药物的新作用。通过JQ1治疗失去干细胞表型可能会导致侵袭性较低、对化疗更敏感的肿瘤，反映出患者预后较好。因此，确定的基因小组可能对侵袭性TNBC患者的临床治疗感兴趣。
Purpose Triple negative breast cancers (TNBCs) are enriched in cells bearing stem-like features, i.e., cancer stem cells (CSCs), which underlie cancer progression. Thus, targeting stemness may be an interesting treatment approach. The epigenetic machinery is crucial for maintaining the stemness phenotype. Bromodomain and extra-terminal domain (BET) epigenetic reader family members are emerging as novel targets for cancer therapy, and have already shown preclinical effects in breast cancer. Here, we aimed to evaluate the effect of the BET inhibitor JQ1 on stemness in TNBC. Methods Transcriptomic, functional annotation and qRT-PCR studies were performed on JQ1-exposed TNBC cells in culture. The results obtained were confirmed in spheroids and spheroid-derived tumours. In addition, limiting dilution, secondary and tertiary tumour sphere formation, matrigel invasion, immunofluorescence and flow cytometry assays were performed to evaluate the effect of JQ1 on CSC features. For clinical outcome analyses, the online tool Kaplan-Meier Plotter and an integrated response database were used. Results We found that JQ1 modified the expression of stemness-related genes in two TNBC-derived cell lines, MDA-MB-231 and BT549. Among these changes, the CD44 Antigen/CD24 Antigen (CD44/CD24) ratio and Aldehyde Dehydrogenase 1 Family Member A1 (ALDH1A1) expression level, i.e., both classical stemness markers, were found to be decreased by JQ1. Using a validated spheroid model to mimic the intrinsic characteristics of CSCs, we found that JQ1 decreased surface CD44 expression, inhibited self-renewal and invasion, and induced cell cycle arrest in G0/G1, thereby altering the stemness phenotype. We also found associations between four of the identified stemness genes, Gap Junction Protein Alpha 1 (GJA1), CD24, Epithelial Adhesion Molecule (EPCAM) and SRY-related HMG-box gene 9 (SOX9), and a worse TNBC patient outcome. The expression of another two of the stemness-related genes was found to be decreased by JQ1, i.e., ATP Binding Cassette Subfamily G Member 2 (ABCG2) and RUNX2, and predicted a low response to chemotherapy in TNBC patients, which supports a role for RUNX2 as a potential predictive marker for chemotherapy response in TNBC. Conclusions We identified a stemness-related gene panel associated with JQ1 and describe how this inhibitor modifies the stemness landscape in TNBC. Therefore, we propose a novel role for JQ1 as a stemness-targeting drug. Loss of the stem cell phenotype via JQ1 treatment could lead to less aggressive and more chemo-sensitive tumours, reflecting a better patient prognosis. Thus, the identified gene panel may be of interest for the clinical management of patients with aggressive TNBC.