Jin Yiting, Zhang Wei, Xu Jiawen, Wang Hongying, Zhang Zijing, Chu Chengyu, Liu Xiuping, Zou Qiang
Department of General Surgery, Huashan Hospital, Fudan University Shanghai, P. R. China.
Department of Pathology, School of Basic Medical Sciences, Fudan University Shanghai, P. R. China.
Int J Clin Exp Pathol. 2015 Oct 1;8(10):12500-8. eCollection 2015.
Ubiquitin carboxy terminal hydrolase-L1 (UCHL1) belongs to the UCH proteases family that deubiquitinates ubiquitin-protein conjugates in the ubiquitin-proteasome system. Our previous research showed that UCH-L1 and EGFR could regulate the expression of P-gp, CD147 and MMPs in multi-drug resistance (MDR) breast cancer cells, respectively. But it is still unclear whether direct regulation exists between the UCH-L1 and EGFR in MDR breast cancer. In order to clarify this, MDR human breast carcinoma cell line MCF7/Adr, that expresses relatively high UCH-L1, and its parental cell line MCF7, that expresses relatively low UCH-L1, were chosen for this study. We added ubiquitin proteasome inhibitor MG-132 into the culture of MCF7/Adr cells and transfected pIRES2-UCH-L1-EGFP plasmid into MCF7 cells, respectively. Using quantitative real-time polymerase chain reaction and western blot analyses, we found accompanying over-expression of UCH-L1, EGFR was up-regulated in both MCF7/ADR and MCF7 cells. Preliminary results indicated the degradation of EGFR might be regulated by ubiquitin level. So we speculated that up-regulated UCH-L1 could promote expression level of EGFR, thereby enhance the invasion and metastasis abilities of tumor cells. Moreover, to further explore the role of UCH-L1 and EGFR, we investigated the expression of UCH-L1, EGFR and P-gp in 65 local advanced breast cancer cases by immunohistochemistry assay. The result showed that the patients not responding to chemotherapy had higher UCH-L1, EGFR and P-gp expression levels and more lymph nodes metastasis. The Kaplan-Meier survival analysis showed that the patients with elevated UCH-L1 expression after chemotherapy presented shorter overall survival and disease free survival times than those with down-regulated or unchanged expression of UCH-L1. Our findings suggest that UCH-L1 may be an indicator of chemotherapy-response and poor-survival in breast cancer. UCH-L1 might be an appropriate target for improving chemo-resistant breast cancer therapy.
泛素羧基末端水解酶L1（UCHL1）属于泛素C末端水解酶家族，在泛素 - 蛋白酶体系统中使泛素 - 蛋白质缀合物去泛素化。我们之前的研究表明，UCH - L1和表皮生长因子受体（EGFR）可分别调节多药耐药（MDR）乳腺癌细胞中P - 糖蛋白（P - gp）、CD147和基质金属蛋白酶（MMPs）的表达。但在MDR乳腺癌中，UCH - L1与EGFR之间是否存在直接调控关系仍不清楚。为了阐明这一点，本研究选用了表达相对较高UCH - L1的MDR人乳腺癌细胞系MCF7/Adr及其表达相对较低UCH - L1的亲本细胞系MCF7。我们分别在MCF7/Adr细胞培养物中添加泛素蛋白酶体抑制剂MG - 132，并将pIRES2 - UCH - L1 - EGFP质粒转染到MCF7细胞中。通过定量实时聚合酶链反应和蛋白质印迹分析，我们发现随着UCH - L1的过表达，MCF7/ADR和MCF7细胞中的EGFR均上调。初步结果表明，EGFR的降解可能受泛素水平调控。因此我们推测，UCH - L1上调可促进EGFR表达水平，从而增强肿瘤细胞的侵袭和转移能力。此外，为进一步探究UCH - L1和EGFR的作用，我们通过免疫组织化学检测了65例局部晚期乳腺癌病例中UCH - L1、EGFR和P - gp的表达。结果显示，化疗无反应的患者UCH - L1、EGFR和P - gp表达水平更高，且淋巴结转移更多。Kaplan - Meier生存分析表明，化疗后UCH - L1表达升高的患者总生存期和无病生存期比UCH - L1表达下调或不变的患者短。我们的研究结果表明，UCH - L1可能是乳腺癌化疗反应和不良生存的一个指标。UCH - L1可能是改善化疗耐药性乳腺癌治疗的一个合适靶点。
