title: Naringenin enhances the anti-tumor effect of doxorubicin through selectively inhibiting the activity of multidrug resistance-associated proteins but not P-glycoprotein.
abstract: OBJECTIVE
  Naringenin has shown paradoxical results to modulate the function of multidrug resistance-associated proteins (MRPs). The aim of this study is to interpret whether naringenin can reverse intrinsic and/or acquired resistance of cancer cells to chemotherapeutic agents.
  
  
  METHODS
  The effects of naringenin on the uptake, retention and cytotoxicity of doxorubicin were investigated in A549, MCF-7, HepG2 and MCF-7/DOX cells. Cellular efflux pathways modulated by naringenin were assessed with their specific substrates and inhibitors. The improved antitumor activity of doxorubicin in combination with naringenin was also investigated in vivo.
  
  
  RESULTS
  The IC(50) values of doxorubicin in combination with naringenin in A549 and MCF-7 cells were approximately 2-fold lower than that of doxorubicin alone. The increased sensitivity to doxorubicin by naringenin in HepG2 and MCF-7/DOX cells was not observed. Naringenin increased the cellular doxorubicin accumulation through inhibiting doxorubicin efflux in the cells expressing MRPs but not P-gp. In contrast to doxorubicin alone, doxorubicin in combination with naringenin enhanced antitumor activity in vivo with low systemic toxicity.
  
  
  CONCLUSIONS
  Naringenin enhances antitumor effect of doxorubicin by selective modulating drug efflux pathways. Naringenin will be a useful adjunct to improve the effectiveness of chemotherapeutic agents in treatment of human cancers.
authors.affiliation: Protein and Peptide Pharmaceutical Laboratory, National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Fa Yun
authors.initials: FY
authors.lastname: Zhang
authors.forename: Gang Jun
authors.initials: GJ
authors.lastname: Du
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Chun Ling
authors.initials: CL
authors.lastname: Zhang
authors.forename: Wan Liang
authors.initials: WL
authors.lastname: Lu
authors.forename: Wei
authors.initials: W
authors.lastname: Liang
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000378:metabolism / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000378:metabolism / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D005260:Female; D044950:Flavanones / Q000494:pharmacology*; D006801:Humans; D020128:Inhibitory Concentration 50; D051379:Mice; D008810:Mice, Inbred C57BL; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D009369:Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D023041:Xenograft Model Antitumor Assays
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D004317:Doxorubicin; D044950:Flavanones; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012333:RNA, Messenger; C513055:ABCB1 protein, human; C005273:naringenin