P-glycoprotein and vacuolar ATPase synergistically confer anthracycline resistance to fission yeast and human cells.
Drug resistance is a major hurdle to the success of chemotherapy. The permeability glycoprotein (P-gp) is an important factor dictating drug access to the cells, as it controls the efflux of chemotherapeutic agents against the concentration gradient. Pmd1, a P-gp-like protein, was recently isolated as a doxorubicin resistance gene in fission yeast. Although the null mutant of pmd1 (Δpmd1) exhibited sensitivity to doxorubicin, it showed an unexpectedly high resistance to the drug at relatively high concentrations. The data presented here suggest that this is due to the presence of cooperative processes that can complement and counteract drug cytotoxicity in the absence of Pmd1. One such factor, Rav1, is an essential factor in controlling the assembly of the pH-regulating transporter vacuolar-ATPase (V-ATPase) in fission yeast. The simultaneous disruption of Pmd1 and Rav1 resulted in a prominent accumulation of doxorubicin in the cytoplasm of cells, accompanied by a decline in cell viability. With concurrent treatment of pharmacological inhibitors in human cervical cancer cells, P-gp and V-ATPase were further shown to act synergistically to sensitize cells to doxorubicin also in the human cells. Furthermore, a novel Cornichon-like protein SPAC2C4.05 (herein named as Cor1) was demonstrated for the first time to be involved in the interaction with P-gp and V-ATPase to counteract doxorubicin-dependent cytotoxicity. Therefore this study identified a molecular cooperation between multiple membrane transporter proteins that confers chemoresistance to cells against the chemical insult of doxorubicin. Interestingly, this network exhibited differential effects to doxorubicin as compared with its close epimeric analog epirubicin, suggestive of the intricacy of the drug response regulated by this synergistic interaction. A model is discussed on how the versatility of this network can differentiate closely related chemical drug structures yet allow for the robustness to counteract a vast range of drugs.
Department of Biochemistry, National University of Singapore, 8 Medical Drive, MD7, #03-08, Singapore 117597. bchces@nus.edu.sg.
Zoey
Z
Tay
Seok Hwee
SH
Koo
Trang Thi Thuy
TT
Nguyen
Tsu Soo
TS
Tan
Ming Li
ML
Chen
Chee Fei
CF
Chin
Kim Kiat
KK
Lim
Wee Han
WH
Ang
Boon Huat
BH
Bay
Edmund J D
EJ
Lee
Ee Sin
ES
Chen
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018943:Anthracyclines / Q000737:chemistry / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004351:Drug Resistance / Q000187:drug effects*; D005260:Female; D006801:Humans; D012568:Schizosaccharomyces / Q000187:drug effects*; D002583:Uterine Cervical Neoplasms / Q000201:enzymology / Q000378:metabolism / Q000473:pathology
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018943:Anthracyclines; D000970:Antineoplastic Agents; D000251:Adenosine Triphosphatases