Overexpression of human phosphoglycerate kinase 1 (PGK1) induces a multidrug resistance phenotype.
BACKGROUND
Multidrug resistance is a significant barrier to the development of successful cancer treatment. To identify genetic alterations that are directly involved in paclitaxel resistance, a functional cloning strategy was developed.


METHODS
Using mRNA from paclitaxel resistant human ovarian cancer cell line SW626TR, a cDNA library was established in a pCMV-Script vector that permits expression of cDNA inserts in mammalian cells. Transfection of the pCMV-Script/SW626TR cDNA library into the paclitaxel-sensitive human osteogenic sarcoma cell line, U-20S, resulted in several paclitaxel-resistant clones.


RESULTS
DNA sequencing of clone C16 demonstrates complete homology to human phosphoglycerate kinase 1 (PGK1). Retransfection of the PGK1 insert into U-20S confers a multidrug resistant phenotype, characterized by a 30-fold increase in paclitaxel resistance, and cross-resistance to vincristine; adriamycin and mitoxantrone, but not methotrexate or cisplatin. Enzymatic analysis of the PGK1 transfectants demonstrates an increase in PGK1 activity as compared to the parental cell line, U-20S. Northern and Western analysis of PGK1 transfectants reveals no change in MDR-1 expression compared with the parental cell line. In addition, co-culture of PGK1 transfectants with verapamil only partially reverses the multidrug resistant phenotype. Rhodamine 123 studies are also consistent with an MDR-1 independent mechanism of increased drug efflux.


CONCLUSIONS
Together this data suggests that PGK1 can induce a multidrug resistant phenotype through an MDR-1 independent mechanism.
Duan
Z
Z
Department of Hematology/Oncology, Massachusetts General Hospital, Boston 02114, USA.
Lamendola
D E
DE
Yusuf
R Z
RZ
Penson
R T
RT
Preffer
F I
FI
Seiden
M V
MV
D000970:Antineoplastic Agents / Q000633:toxicity*; D001692:Biological Transport; D001859:Bone Neoplasms / Q000235:genetics*; D002470:Cell Survival / Q000187:drug effects; D018432:Drug Resistance, Multiple / Q000235:genetics*; D015723:Gene Library; D006801:Humans; D007527:Isoenzymes / Q000235:genetics*; D012516:Osteosarcoma / Q000235:genetics*; D017239:Paclitaxel / Q000633:toxicity; D010735:Phosphoglycerate Kinase / Q000235:genetics*; D014700:Verapamil / Q000493:pharmacokinetics
D000970:Antineoplastic Agents; D007527:Isoenzymes; D014700:Verapamil; D010735:Phosphoglycerate Kinase; D017239:Paclitaxel