Sorcin, an important gene associated with multidrug-resistance in human leukemia cells.
Sorcin, or soluble resistance-related calcium-binding protein, is a 22kD calcium-binding protein initially identified in many mutli-drug resistant (MDR) cell lines. We previously observed by gene profiling that sorcin is significantly up-regulated in a doxorubicin-induced MDR leukemia cell line, K562/A02, over its parent cells. We have also demonstrated that the level of sorcin expression in leukemia patients correlates not only directly with that of the mdr1 gene, but also inversely with patients' response to chemotherapies and overall prognosis. In this report, we have carried out experiments to dissect out the contribution of sorcin by itself to drug resistant phenotype in K562 cells. Overexpression of sorcin protein by gene transfection in K562 cells resulted in increased drug resistance, from 4.1- to 22.5-fold, to a variety of chemotherapeutic agents, including doxorubicin, etoposide, homoharringtonine and vincristine. On the other hand, inhibition of sorcin expression in both MDR K562/A02 and the sorcin-transfected K562 cells with sorcin-targeting small interfering RNA led to varying extent of reversal of drug resistance. These results confirm that sorcin is an important gene associated with the development of MDR in leukemia cells.
Zhou
Yuan
Y
Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 288 Nanjing Road, Tianjin 300020, PR China.
Xu
Yuanfu
Y
Tan
Yaohong
Y
Qi
Jing
J
Xiao
Ying
Y
Yang
Chunzheng
C
Zhu
Zhenping
Z
Xiong
Dongsheng
D
D001483:Base Sequence; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000235:genetics*; D017931:DNA Primers; D018432:Drug Resistance, Multiple / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D006801:Humans; D020014:K562 Cells; D007938:Leukemia / Q000235:genetics* / Q000473:pathology; D034741:RNA, Small Interfering
D002135:Calcium-Binding Proteins; D017931:DNA Primers; D034741:RNA, Small Interfering; C503113:SRI protein, human