title: T-2307, a novel arylamidine, is transported into Candida albicans by a high-affinity spermine and spermidine carrier regulated by Agp2.
abstract: T-2307, a novel arylamidine, exhibits potent broad-spectrum activities against pathogenic fungi, particularly Candida albicans. We previously reported that T-2307 uptake was mainly mediated by a saturable high-affinity carrier at the MIC for C. albicans. Since we hypothesized that the potent anticandidal activity arose from accumulation via the high-affinity carrier, we characterized the specificity and kinetic features of the carrier.
  
  
  
  The MICs of T-2307 for C. albicans strains were evaluated in the presence and absence of potential competitive substrates. The cells were exposed to [(14)C]T-2307, [(14)C]spermine or [(14)C]spermidine in the presence of unlabelled T-2307, pentamidine, propamidine, or competitive substrates if necessary, and the radioactivity in the cells was measured. C. albicans gene deletion was performed using a one-step PCR-based technique.
  
  
  
  Coapplication with exogenous spermine or spermidine decreased the antifungal activity and uptake of T-2307 in C. albicans strains. T-2307 competitively inhibited spermine and spermidine uptake with inhibition constants similar to its Km for the high-affinity carrier. The comparison of MICs and kinetic values between T-2307 and other diamidine compounds suggested that the different antifungal properties could be partially attributable to the variations in their affinity with the carrier. Studies of gene deletion mutants revealed that T-2307 was transported into C. albicans by a high-affinity spermine and spermidine carrier regulated by Agp2.
  
  
  
  Uptake of T-2307 via the high-affinity spermine and spermidine carrier regulated by Agp2 could contribute to its potent antifungal activity. Further investigation is required to identify the high-affinity carrier for potential targeting with novel therapies.
authors.affiliation: Research Laboratories, Toyama Chemical Co., Ltd, 2-4-1 Shimookui, Toyama, Japan Second Department of Internal Medicine, Nagasaki University, Nagasaki, Japan Division of Infectious Diseases, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan hiroshi_nishikawa@toyama-chemical.co.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nishikawa
authors.affiliation: Research Laboratories, Toyama Chemical Co., Ltd, 2-4-1 Shimookui, Toyama, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Sakagami
authors.affiliation: Research Laboratories, Toyama Chemical Co., Ltd, 2-4-1 Shimookui, Toyama, Japan.
authors.forename: Eio
authors.initials: E
authors.lastname: Yamada
authors.affiliation: Research Laboratories, Toyama Chemical Co., Ltd, 2-4-1 Shimookui, Toyama, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Fukuda
authors.affiliation: Research Laboratories, Toyama Chemical Co., Ltd, 2-4-1 Shimookui, Toyama, Japan.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Hayakawa
authors.affiliation: Research Laboratories, Toyama Chemical Co., Ltd, 2-4-1 Shimookui, Toyama, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Nomura
authors.affiliation: Research Laboratories, Toyama Chemical Co., Ltd, 2-4-1 Shimookui, Toyama, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Mitsuyama
authors.affiliation: Second Department of Internal Medicine, Nagasaki University, Nagasaki, Japan Division of Infectious Diseases, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors.forename: Taiga
authors.initials: T
authors.lastname: Miyazaki
authors.affiliation: Second Department of Internal Medicine, Nagasaki University, Nagasaki, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mukae
authors.affiliation: Second Department of Internal Medicine, Nagasaki University, Nagasaki, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kohno
mesh_terms: D000578:Amidines / Q000378:metabolism*; D000935:Antifungal Agents / Q000378:metabolism*; D001692:Biological Transport; D002176:Candida albicans / Q000378:metabolism*; D002250:Carbon Radioisotopes / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D017353:Gene Deletion; D007553:Isotope Labeling; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D013095:Spermidine / Q000378:metabolism; D013096:Spermine / Q000378:metabolism
chemical_list: D000578:Amidines; D000935:Antifungal Agents; D002250:Carbon Radioisotopes; D002352:Carrier Proteins; C573060:T-2307; D013096:Spermine; D013095:Spermidine