Bojmar Linda, Karlsson Elin, Ellegård Sander, Olsson Hans, Björnsson Bergthor, Hallböök Olof, Larsson Marie, Stål Olle, Sandström Per
Surgery, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Department of Surgery in Östergötland, County Council of Östergötland, Linköping, Sweden.
Oncology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Department of Oncology, County Council of Östergötland, Linköping, Sweden.
PLoS One. 2013 Dec 20;8(12):e84815. doi: 10.1371/journal.pone.0084815. eCollection 2013.
The role of the epithelial-mesenchymal transition (EMT) in cancer has been studied extensively in vitro, but involvement of the EMT in tumorigenesis in vivo is largely unknown. We investigated the potential of microRNAs as clinical markers and analyzed participation of the EMT-associated microRNA-200-ZEB-E-cadherin pathway in cancer progression. Expression of the microRNA-200 family was quantified by real-time RT-PCR analysis of fresh-frozen and microdissected formalin-fixed paraffin-embedded primary colorectal tumors, normal colon mucosa, and matched liver metastases. MicroRNA expression was validated by in situ hybridization and after in vitro culture of the malignant cells. To assess EMT as a predictive marker, factors considered relevant in colorectal cancer were investigated in 98 primary breast tumors from a treatment-randomized study. Associations between the studied EMT-markers were found in primary breast tumors and in colorectal liver metastases. MicroRNA-200 expression in epithelial cells was lower in malignant mucosa than in normal mucosa, and was also decreased in metastatic compared to non-metastatic colorectal cancer. Low microRNA-200 expression in colorectal liver metastases was associated with bad prognosis. In breast cancer, low levels of microRNA-200 were related to reduced survival and high expression of microRNA-200 was predictive of benefit from radiotheraphy. MicroRNA-200 was associated with ER positive status, and inversely correlated to HER2 and overactivation of the PI3K/AKT pathway, that was associated with high ZEB1 mRNA expression. Our findings suggest that the stability of microRNAs makes them suitable as clinical markers and that the EMT-related microRNA-200-ZEB-E-cadherin signaling pathway is connected to established clinical characteristics and can give useful prognostic and treatment-predictive information in progressive breast and colorectal cancers.
上皮-间质转化（EMT）在癌症中的作用已在体外进行了广泛研究，但EMT在体内肿瘤发生中的参与情况在很大程度上尚不清楚。我们研究了微小RNA作为临床标志物的潜力，并分析了与EMT相关的微小RNA-200-ZEB-E-钙黏蛋白通路在癌症进展中的参与情况。通过对新鲜冷冻和显微切割的福尔马林固定石蜡包埋的原发性结直肠癌肿瘤、正常结肠黏膜及匹配的肝转移灶进行实时RT-PCR分析，对微小RNA-200家族的表达进行定量。通过原位杂交和恶性细胞的体外培养验证微小RNA的表达。为了评估EMT作为预测标志物，在一项治疗随机研究的98例原发性乳腺癌中研究了在结直肠癌中被认为相关的因素。在原发性乳腺癌和结直肠癌肝转移灶中发现了所研究的EMT标志物之间的关联。上皮细胞中微小RNA-200的表达在恶性黏膜中低于正常黏膜，并且与非转移性结直肠癌相比，在转移性结直肠癌中也降低。结直肠癌肝转移灶中微小RNA-200低表达与不良预后相关。在乳腺癌中，微小RNA-200低水平与生存率降低相关，而微小RNA-200高表达可预测放疗获益。微小RNA-200与雌激素受体（ER）阳性状态相关，与人类表皮生长因子受体2（HER2）及磷脂酰肌醇-3激酶/蛋白激酶B（PI3K/AKT）通路的过度激活呈负相关，PI3K/AKT通路过度激活与锌指E盒结合蛋白1（ZEB1）mRNA高表达相关。我们的研究结果表明，微小RNA的稳定性使其适合作为临床标志物，并且与EMT相关的微小RNA-200-ZEB-E-钙黏蛋白信号通路与既定的临床特征相关，可为进展期乳腺癌和结直肠癌提供有用的预后和治疗预测信息。
