Interaction between CD147 and P-glycoprotein and their regulation by ubiquitination in breast cancer cells.
BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Wang
Wen-Juan
WJ
Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, China.
Li
Qing-Quan
QQ
Xu
Jing-Da
JD
Cao
Xi-Xi
XX
Li
Hai-Xia
HX
Tang
Feng
F
Chen
Qi
Q
Yang
Jin-Ming
JM
Xu
Zu-De
ZD
Liu
Xiu-Ping
XP
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D051926:Basigin / Q000235:genetics / Q000378:metabolism*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D017364:Collagenases / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D017239:Paclitaxel / Q000494:pharmacology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D043222:Ubiquitin Thiolesterase / Q000235:genetics / Q000378:metabolism; D054875:Ubiquitination
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051926:Basigin; D043222:Ubiquitin Thiolesterase; D017364:Collagenases; D046988:Proteasome Endopeptidase Complex; D017239:Paclitaxel