Multidrug-resistant cancer cells overexpressing P-glycoprotein (P-gp) display variations in invasive and metastatic ability through the upregulation of the extracellular matrix metalloproteinase (MMP) inducer (CD147). However, the direct linkage between these two proteins is still unclear.We used immunoprecipitation, immunofluorescence analysis, migration and invasion assays, drug sensitivity assay and Western blot to measure the physical and functional interaction between P-gp and CD147. Then we transfected vectors carrying ubiquitin C-terminal hydrolase L1 (UCH-L1) or UCH-L1 siRNA into MCF7 and MCF7/Adr cells, respectively, and investigated the role of UCH-L1 in the regulation of the expression and degradation of P-gp, CD147 and MMP-1, MMP-2, and MMP-9 by quantitative real-time polymerase chain reaction, Western blot and immunoprecipitation.In this paper, we showed that P-gp and CD147 interacted with each other, and that the ubiquitin-proteasome pathway played an important role in the turnover of them. In addition, we found that inhibition of N-glycosylation increased the ubiquitination and degradation of P-gp and CD147, and affected their function. UCH-L1 not only regulated the expression of P-gp, CD147 and MMP-1, MMP-2, and MMP-9, but also the ubiquitination and degradation of P-gp and CD147 in breast cancer cells.Our results demonstrate a mechanism underlying the linkage between multidrug resistance and tumor metastasis, and suggest for the first time that modulating the ubiquitination of P-gp and CD147 might be a novel method for tumor therapy.

作者：Wen-Juan, Wang；Qing-Quan, Li；Jing-Da, Xu；Xi-Xi, Cao；Hai-Xia, Li；Feng, Tang；Qi, Chen；Jin-Ming, Yang；Zu-De, Xu；Xiu-Ping, Liu

来源：Chemotherapy 2008 年 54卷 4期