Organic UV filters inhibit multixenobiotic resistance (MXR) activity in Tetrahymena thermophila: investigations by the Rhodamine 123 accumulation assay and molecular docking.
Multixenobiotic resistance (MXR) transporters, which belong to ATP-binding cassette (ABC) family proteins, are present in living organisms as a first line of defense system against xenobiotics and environmental contaminants. The effects of six organic UV filters (4-methyl -benzylidene camphor, 4-MBC; benzophenone-3, BP-3; butyl methoxydibenzoyl-methane, BM-DBM; ethylhexyl methoxy cinnamate, EHMC; octocrylene, OC and homosalate, HMS) on multixenobiotic resistance (MXR) in Tetrahymena thermophila were investigated in this study. It was found that 4-MBC, BP-3 and BM-DBM could significantly inhibit activity of the MXR system, causing concentration dependent accumulation of rhodamine 123; while EHMC, OC and HMS had weak MXR inhibition. The IC50 (50 % inhibition concentration) values of 4-MBC, BP-3 and BM-DBM were 23.54, 40.59 and 26.37 μM, respectively, with inhibitory potentials of 23.1, 13.4 and 20.6 % relative to verapamil (VER, a model inhibitor of P-glycoprotein). Our results firstly provide the evidence for UV filters inhibition effect on MXR in aquatic organisms. In addition, it was revealed by molecular docking analysis that the selected six UV filters can occupy the same binding site on T. thermophila P-gp as VER does; and form H-bonds with residues Ser 328 and/or Asn 281. This study raises the awareness of aquatic ecological risk from the organic UV filters exposure, as they would be involved in potentiating toxic effects by chemosensitizing.
School of Environmental Science and Engineering, Shanghai Jiao Tong University, No.800 Dongchuan Road, Minhang District, Shanghai, 200240, China.|School of Resource and Environment, Ningxia University, Yinchuan, 750021, China.
Li
L
Gao
School of Environmental Science and Engineering, Shanghai Jiao Tong University, No.800 Dongchuan Road, Minhang District, Shanghai, 200240, China. taoyuan@sjtu.edu.cn.
Tao
T
Yuan
School of Life Science, Hubei University, Wuhan, 430062, China.
Peng
P
Cheng
School of Environmental Science and Engineering, Shanghai Jiao Tong University, No.800 Dongchuan Road, Minhang District, Shanghai, 200240, China.
Chuanqi
C
Zhou
School of Environmental Science and Engineering, Shanghai Jiao Tong University, No.800 Dongchuan Road, Minhang District, Shanghai, 200240, China.
Junjie
J
Ao
School of Environmental Science and Engineering, Shanghai Jiao Tong University, No.800 Dongchuan Road, Minhang District, Shanghai, 200240, China.
Wenhua
W
Wang
School of Life Science, Hubei University, Wuhan, 430062, China.
Haimou
H
Zhang
D018435:ATP Binding Cassette Transporter, Subfamily B; D001681:Biological Assay; D004351:Drug Resistance / Q000187:drug effects*; D062105:Molecular Docking Simulation; D020112:Rhodamine 123 / Q000378:metabolism*; D013473:Sunscreening Agents / Q000633:toxicity*; D016808:Tetrahymena thermophila / Q000502:physiology*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D018435:ATP Binding Cassette Transporter, Subfamily B; D013473:Sunscreening Agents; D014874:Water Pollutants, Chemical; D020112:Rhodamine 123
Molecular docking; Multixenobiotic resistance; P-glycoprotein; Tetrahymena thermophila; UV filter