Jin Min-Sun, Hyun Chang Lim, Park In Ae, Kim Ji Young, Chung Yul Ri, Im Seock-Ah, Lee Kyung-Hun, Moon Hyeong-Gon, Ryu Han Suk
Department of Pathology, Buchen St. Mary's Hospital, Catholic university, Gyeonggi-do, South Korea.
Department of Pathology, Jeju National University Hospital, Jeju, South Korea.
Tumour Biol. 2016 Apr;37(4):4743-53. doi: 10.1007/s13277-015-4231-3. Epub 2015 Oct 30.
Absence of therapeutic targets poses a critical hurdle in improving prognosis for patients with triple negative breast cancer (TNBC). We evaluated interaction between SIRT1 and epithelial mesenchymal transition (EMT)-associated proteins as well as the role of combined protein expression as a predictor of lymph node metastasis and clinical outcome in TNBC through in vivo and vitro studies. Three hundred nineteen patients diagnosed with TNBC were chosen, immunohistochemical staining for SIRT1 and EMT-related markers' expression was performed on tissue microarrays, and in vitro experiments with each of the three human TNBC cell lines were carried out. The cohort was reclassified according to the use of adjuvant chemotherapy, tumor size, and AJCC stage to analyze the prognostic role of SIRT1 and EMT-related proteins' expression considering different therapeutic modalities and AJCC stages. Combination of four proteins including SIRT1 and three EMT-related proteins was revealed to be a statistically significant independent predictor of lymph node metastasis in the tumor size cohort as well as in the total patient population. Upon Cox regression analysis, increased expression level of the combined proteins correlated with decreased disease-free survival in the total patients as well as those who received adjuvant chemotherapy and those who had early stage breast cancer. In additional in vitro experiments, inhibition of SIRT1 expression with small interfering RNA (siRNA) suppressed tumor invasion in three different TNBC cell lines, and altered expression levels of EMT-related proteins following SIRT1 gene inhibition were identified on western blotting and fluorescence activated cell sorting (FACS) analysis; on the other hand, no change in expression levels of the cell cycle-related factors was observed. Our analysis showed the potential role of SIRT1 in association with EMT-related factors on tumor invasion, metastasis, and disease-free survival in TNBC, SIRT1, and associated EMT-related markers may offer a new prognostic indicator as well as a novel therapeutic candidate.
缺乏治疗靶点是改善三阴性乳腺癌（TNBC）患者预后的关键障碍。我们通过体内和体外研究评估了SIRT1与上皮-间质转化（EMT）相关蛋白之间的相互作用，以及联合蛋白表达作为TNBC淋巴结转移和临床结局预测指标的作用。选取319例诊断为TNBC的患者，在组织芯片上进行SIRT1和EMT相关标志物表达的免疫组化染色，并对三种人TNBC细胞系分别进行体外实验。根据辅助化疗的使用、肿瘤大小和美国癌症联合委员会（AJCC）分期对队列进行重新分类，以分析SIRT1和EMT相关蛋白表达在考虑不同治疗方式和AJCC分期时的预后作用。包括SIRT1和三种EMT相关蛋白在内的四种蛋白的联合被证明是肿瘤大小队列以及全部患者人群中淋巴结转移的统计学显著独立预测指标。经Cox回归分析，联合蛋白表达水平升高与全部患者以及接受辅助化疗的患者和早期乳腺癌患者的无病生存期缩短相关。在另外的体外实验中，用小干扰RNA（siRNA）抑制SIRT1表达可抑制三种不同TNBC细胞系的肿瘤侵袭，并且在蛋白质印迹和荧光激活细胞分选（FACS）分析中确定了SIRT1基因抑制后EMT相关蛋白表达水平的变化；另一方面，未观察到细胞周期相关因子表达水平的变化。我们的分析显示了SIRT1与EMT相关因子在TNBC肿瘤侵袭、转移和无病生存方面的潜在作用，SIRT1以及相关的EMT相关标志物可能提供一种新的预后指标以及一种新的治疗候选物。
