Multidrug resistance-associated protein 1 (MRP1) expression in neuroblastoma cell lines and primary tumors.
METHODS
MRP1 expression by neuroblastomas was evaluated by Northern blot analysis in 21 cell lines and 90 primary untreated tumors. Cytotoxicity assay in cell lines was performed for five anticancer drugs used in treating neuroblastoma.


RESULTS
MRP1 expression did not correlate with drug resistance or with MYCN RNA expression in cell lines. MRP1 expression was higher in drug-sensitive cell lines established after chemotherapy relative to cell lines at diagnosis, but highly drug-resistant cell lines showed low MRP1 expression. Positive expression of MRP1 RNA in primary tumors was associated with a poorer survival relative to MRP1-negative tumors. However, MRP1 expression levels did not correlate with age, stage, MYCN amplification, or MYCN expression, and higher MRP1 expression was not associated with a worse outcome.


CONCLUSIONS
In neuroblastoma, positive MRP1 RNA expression at diagnosis has prognostic significance, but high drug resistance is conferred by mechanisms other than MRP1.
Goto
H
H
Division of Hematology-Oncology, Childrens Hospital Los Angeles, University of Southern California School of Medicine, Los Angeles, California 90027, USA.
Keshelava
N
N
Matthay
K K
KK
Lukens
J N
JN
Gerbing
R B
RB
Stram
D O
DO
Seeger
R C
RC
Reynolds
C P
CP
D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D019008:Drug Resistance, Neoplasm; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007223:Infant; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009447:Neuroblastoma / Q000188:drug therapy* / Q000235:genetics*; D011379:Prognosis; D012333:RNA, Messenger / Q000096:biosynthesis; D014407:Tumor Cells, Cultured
D018528:ATP-Binding Cassette Transporters; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012333:RNA, Messenger