1. Antifungal styrylquinolines as inhibitors of Cdr1 transporter of Candida albicans
Joanna Szczepaniak1, Robert Musioł2, Wioleta Cieślik2, Anna Romanowicz1 and Anna Krasowska1*
1Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
2Institute of Chemistry, University of Silesia, Katowice, Poland
Candida species is a part of human microflora in healthy humans but under certain conditions, Candida may cause a wide variety of infections on mucosal surfaces as well as a bloodstream infections, which is known as candidaemia [Fig.1].
Fig.1. Candida albicans yeast, pseudohyphae and hyphae form
C. albicans is shown to gain resistance to commonly used antifungals, such as azoles. One of the main mechanism of resistance is activity of ABC (ATP-binding cassettes) transporters, Cdr1p and Cdr2p, which actively export xenobiotics out of the cell. We used strains with deletions of gene encoded Cdr1p and Cdr2p [Tab.1]. R1 R2
In this study we present styrylquinolines as new antifungal agents [Fig.2].
Preliminary screening showed inhibition of the C. albicans growth by those compounds and their synergistic activity with fluconazole. [Tab.2 and Tab.3].
Tab.1. C. albicans strains used in this study
Fig.2. Chemical structure of styryloquinolines
Strain
Genotype
CAF 2-1
ura3Δ::imm434/URA3
DSY 448
cdr1Δ::hisG-URA3-hisG/cdr1Δ::hisG
DSY 653
cdr2Δ::hisG-URA3-hisG/cdr2Δ::hisG
DSY 654
cdr1Δ::hisG/cdr1Δ::hisG cdr2Δ::hisG-URA3-hisG/cdr2Δ::hisG
Tab.2. Minimal Inhibitory Concentrations (MIC) of styryloguinolins
Styrylquinolines are substrate for Cdr1p pump which we
confirmed using the rhodamine 6G assay [Fig.3]
Tab.3. Synergistic effect of fluconazole and styryloquinolines [mM]
CAF 2-1
CDR1Δ
CDR2Δ
CDR1Δ CDR2Δ
0,05
0,1
0,2
WK86
100
90,7
91,5
89,0 81
69,6
68,8
90,5
87,9
78,9
79,4
74,3
73,5
92,4
87,1
88,4
85,5
95,9
85,2
79,7
67,1
92,5
81,6
82,2
78,7
91,3
72,8
47,1
43,9
78,5
86,6
88,1
86,0
74,6
71,2
58,2
85,4
81,5
82,0
76,2
79,1
63,5
26,5
23,4
62,1
86,5
88,3
86,1
57,4
57,8
54,4
42,6
65,9
82,5
84,3
80,0
56,5
29,7
25,2
23,3
0,4
WK86B
91,1
87,4
77,7
95,8
88,8 82
92,8
89,7
89,1
49,3
51,1
93,9
90,0
82,3
81,2
80,4
85,9
92,1
86,2
58,6
21,2
13,2
78,3
88,6
85,3
79,5
64,2
82,1
65,6
48,8
73,1
86,8
84,9
53,0
16,3
12,1
64,7
85,8
53,3
54,5
41,5
33,1
48,9
88,0
85,6
80,7
47,6
15,7
12,6
10,1
Fig.3. Rhodamine G6 efflux in C.albicans CAF2-1
strain blocked by styryloquinolines WK86
and WK86B
The work was supported by Wroclaw Research Centre EIT+
within the project "The Application of Nanotechnology
in Advanced Materials” - NanoMat (POIG /08)
co-financed by the European Regional Development Fund
(Operational Program Innovative Economy, 1.1.2)
and by National Centre Science Poland 2013/09/B/NZ7/00423