title: High-throughput screening identifies Ceefourin 1 and Ceefourin 2 as highly selective inhibitors of multidrug resistance protein 4 (MRP4).
abstract: Multidrug resistance protein 4 (MRP4/ABCC4), a member of the ATP-binding cassette (ABC) transporter superfamily, is an organic anion transporter capable of effluxing a wide range of physiologically important signalling molecules and drugs. MRP4 has been proposed to contribute to numerous functions in both health and disease; however, in most cases these links remain to be unequivocally established. A major limitation to understanding the physiological and pharmacological roles of MRP4 has been the absence of specific small molecule inhibitors, with the majority of established inhibitors also targeting other ABC transporter family members, or inhibiting the production, function or degradation of important MRP4 substrates. We therefore set out to identify more selective and well tolerated inhibitors of MRP4 that might be used to study the many proposed functions of this transporter. Using high-throughput screening, we identified two chemically distinct small molecules, Ceefourin 1 and Ceefourin 2, that inhibit transport of a broad range of MRP4 substrates, yet are highly selective for MRP4 over other ABC transporters, including P-glycoprotein (P-gp), ABCG2 (Breast Cancer Resistance Protein; BCRP) and MRP1 (multidrug resistance protein 1; ABCC1). Both compounds are more potent MRP4 inhibitors in cellular assays than the most widely used inhibitor, MK-571, requiring lower concentrations to effect a comparable level of inhibition. Furthermore, Ceefourin 1 and Ceefourin 2 have low cellular toxicity, and high microsomal and acid stability. These newly identified inhibitors should be of great value for efforts to better understand the biological roles of MRP4, and may represent classes of compounds with therapeutic application.
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: lcheung@ccia.unsw.edu.au.
authors: Leanna
authors: L
authors: Cheung
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: cflemming@ccia.unsw.edu.au.
authors: Claudia L
authors: CL
authors: Flemming
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: fwatt7@gmail.com.
authors: Fujiko
authors: F
authors: Watt
authors: Department of Pharmacology, University of Cambridge, Cambridge, UK. Electronic address: nana1017@gmail.com.
authors: Nanako
authors: N
authors: Masada
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: dyu@ccia.unsw.edu.au.
authors: Denise M T
authors: DM
authors: Yu
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: thuynh@ccia.unsw.edu.au.
authors: Tony
authors: T
authors: Huynh
authors: Division of Cancer Biology & Genetics, Queen's University Cancer Research Institute, Kingston, ON, Canada. Electronic address: conseilg@queensu.ca.
authors: Gwenaëlle
authors: G
authors: Conseil
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: amandativnan@rcsi.ie.
authors: Amanda
authors: A
authors: Tivnan
authors: OncoTartis, Inc., 640 Ellicott St., Suite 444, Buffalo, NY, USA. Electronic address: apolinsk@tartiscorp.com.
authors: Alexander
authors: A
authors: Polinsky
authors: Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, NY, USA. Electronic address: Andrei.Gudkov@RoswellPark.org.
authors: Andrei V
authors: AV
authors: Gudkov
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: m.munoz@centenary.org.au.
authors: Marcia A
authors: MA
authors: Munoz
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: suya_v@yahoo.com.
authors: Anasuya
authors: A
authors: Vishvanath
authors: Department of Pharmacology, University of Cambridge, Cambridge, UK. Electronic address: dmfc2@cam.ac.uk.
authors: Dermot M F
authors: DM
authors: Cooper
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: mhenderson@ccia.unsw.edu.au.
authors: Michelle J
authors: MJ
authors: Henderson
authors: Division of Cancer Biology & Genetics, Queen's University Cancer Research Institute, Kingston, ON, Canada. Electronic address: spc.cole@queensu.ca.
authors: Susan P C
authors: SP
authors: Cole
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: jfletcher@ccia.unsw.edu.au.
authors: Jamie I
authors: JI
authors: Fletcher
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: mhaber@ccia.unsw.edu.au.
authors: Michelle
authors: M
authors: Haber
authors: Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, PO Box 81, Randwick 2031, NSW, Australia. Electronic address: mnorris@ccia.unsw.edu.au.
authors: Murray D
authors: MD
authors: Norris
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D052160:Benzothiazoles / Q000494:pharmacology*; D002460:Cell Line / Q000187:drug effects; D018432:Drug Resistance, Multiple / Q000187:drug effects; D057166:High-Throughput Screening Assays / Q000379:methods*; D006801:Humans; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D018675:Toxicity Tests; D014230:Triazoles / Q000494:pharmacology*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D052160:Benzothiazoles; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins; D011720:Pyrazoles; D011743:Pyrimidines; D014230:Triazoles; C073492:ABCC4 protein, human; C116614:ABCG2 protein, human; C000592124:ceefourin 1; C000592125:ceefourin 2; C421109:multidrug resistance-associated protein 1
keywords: 6-Mercaptopurine (PubChem CID: 667490); ABCC4; Ceefourin; Cyclic AMP (PubChem CID: 6076); Estradiol 17-beta-d-glucuronide (PubChem CID: 5281887); High-throughput screening; MK-571 (PubChem CID: 5281888); MRP4 inhibitor; Multidrug resistance; SN-38 (PubChem CID: 104842); d-Luciferin (PubChem CID: 6800291)