Peng Li
§
, Chao Huang
§
, Yingxue Fu
§
, Jinan Wang
§
, Ziyin Wu, Jinlong Ru, Chunli Zheng, Zihu
Guo, Xuetong Chen, Wei Zhou, Wenjuan Zhang, Yan Li, Jianxin Chen , Aiping Lu, Yonghua
Wang*
§
Contributing equally to this work
*Corresponding author: Yonghua Wang; E-mail: yh_wang@nwsuaf.edu.cn
Supplementary Figure 1. The drug –drug similarity between components of each drug combination. The drug
–drug similarity of known effective drug combinations were separately measured for six molecular/pharmacological descriptors, i.e., (a) Anatomical Therapeutic and
Chemical (ATC) classification system, (b) chemical structure, (c) target protein sequence, (d) distance in protein-protein interaction (PPI) network, (e) Gene Ontology (GO) and (f) drug side effects. The distribution of similarities for all the six descriptors are shifted toward higher values compared with that of random control ( P < 0.01). For instance, the distribution of ATC similarity shows that 70% of combinations belong to the same therapeutic category (from the first to fifth level of the ATC code) compared with 20% expected by chance ( P ≪ 0.01), indicating that drugs in combinations often have therapeutic effects in common. The most obvious example is the combination of anticancer drugs.
Supplementary Figure 2.
Database evaluation.
Comparison of the (a) chemical diversity and
(b) disease diversity of PreDC (blue line) with DrugBank (green line).
1
Supplementary Figure 3. The red line corresponds to the disease similarity between our prediction results and the benchmark datasets (mean = 0.56). The green line corresponds to random similarity distribution (mean = 0.16).
Supplementary Table 1 . The Pearson correlation coefficients of six features between each other effective drug combinations (EDCs).
PCC (P value) Structure ATC Side Effect GO PPI Sequence
Structure
1 0.48 0.32 0.4 0.25 0.35
ATC
0.48 1 0.23 0.39 0.18 0.38
Side Effect
0.32 0.23 1 0.16 0.12 0.06
GO
0.4 0.39 0.16 1 0.29 0.44
PPI
0.25 0.18 0.12 0.29 1 0.4
Sequence
Structure
0.35 0.38 0.06 0.44 0.4 1
Supplementary Table 2 . The Pearson correlation coefficients of six features between each other undesirable drug-drug interactions (UDDIs).
PCC (P value) Structure ATC Side Effect GO PPI Sequence
1 0.33 0.15 0.3 0.24 0.29
ATC
0.33 1 0.1 0.35 0.23 0.36
Side Effect
0.15 0.1 1 0.04 0.16 0.05
GO
0.3 0.35 0.04 1 0.37 0.51
2
PPI
0.24 0.23 0.16 0.37 1 0.43
Sequence
0.29 0.36 0.05 0.51 0.43 1
Supplementary Table 3 .
Performance of PEA model by dividing drugs into ‘new drugs’ and ‘known drugs’.
AUC of
(ROC)
Both known drugs One known and one new drug
Both new drugs
EDCs
UDDIs
0.88
0.92
0.836
0.86
0.76
0.71
Supplementary Table 4 . Distribution of experimentally validated drug combinations in the binary diagram
Quadrant 1' 1 2 4
Anti-infection 11 (8) 27 (23)
Anti-cancer 33 (27) 48 (34)
Total 44 (35) 75 (57)
1 (1)
1 (0)
2 (1)
19 (14)
6 (5)
25 (19)
Supplementary Table 5 . Benchmark datasets of drug combinations derived from the literature
Supplementary Table 5 can be downloaded as additional excel fileat our website http://sm.nwsuaf.edu.cn/lsp/predc.php.
3
Supplementary Table 6 . The full list of the verified proportion and q-values between or within drug classes
Drug class Drug class
Number of all possible drug combinations
Number of predicted drug combinations
Number of drug combinations in gold-standard dataset
Number of drug combinations in benchmark dataset a b
Verified proportion
P -value q-value
(<0.05)
L01B
D06A
D06A
D10A
D10A
H02A
L01B
M01A
R03D
G01A
D07A
A01A
J05A
D07X
D10A
H02A
L01B
D10A
J01D
A07A
L01C
A01A
R01A
L01C
H02A
J01X
M01A
R03A
S02A
L01D
R05D
R06A
S03B
R03A
R03A
J05A
R03A
L04A
R03A
L04A
G01A
J01X
J01X
L01X
J01X
R03A
72
143
90
105
52
80
111
117
64
93
216
96
336
122
387
167
135
300
48
180
64
194
153
12
16
10
12
15
28
13
25
14
10
14
10
14
18
20
11
22
45
15
10
15
12
14
2
1
3
1
3
2
7
12
2
6
3
1
11
9
44
6
5
16
0
2
0
5
2
6
7
13
6
6
8
5
13
7
5
7
5
8
10
11
6
12
29
9
6
9
7
8
0.52
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.47
0.46
0.46
0.64
0.60
0.60
0.60
0.58
0.57
0.57
0.56
0.55
0.55
0.55
1.0E-11 7.1E-09
3.7E-03 2.4E-02
9.0E-06 5.8E-04
5.5E-04 8.3E-03
1.1E-05 6.4E-04
7.3E-06 5.8E-04
9.5E-07 1.1E-04
4.8E-04 7.3E-03
4.7E-05 1.6E-03
1.5E-04 3.5E-03
3.4E-05 1.4E-03
2.7E-03 2.0E-02
6.3E-03 3.1E-02
7.7E-03 3.4E-02
8.2E-06 5.8E-04
8.9E-04 1.1E-02
6.0E-03 3.0E-02
4.1E-05 1.5E-03
1.2E-02 4.1E-02
6.0E-04 8.4E-03
1.7E-02 4.8E-02
8.0E-03 3.4E-02
4.5E-04 7.1E-03
4
D10A
R01A
R03B
D07X
G01A
A01A
J01F
S01B
D10A
J01C
J01G
L01B
A07E
D10A
L01D
A07E
A01A
R03A
G01A
A01A
D07A
L01X
A01A
A01A
M02A
R01A
C05A
A01A
A02B
D06A
J01G
R03C
S03A
G01A
H02A
S02A
S01A
S03A
S01A
J01X
S02A
L01X
S03A
M02A
L01X
R03A
G01A
S01B
S02B
S03A
R03C
L01X
D10A
J02A
N02A
S03A
G01A
A07A
R06A
S01B
96
101
56
78
104
120
177
96
357
216
69
559
120
135
130
148
210
96
109
60
903
167
151
64
120
473
64
167
96
65
10
10
15
23
23
13
13
16
27
11
11
102
14
17
23
29
21
21
12
12
58
15
10
11
11
33
16
23
21
19
5
3
3
6
2
2
2
0
4
7
4
1
37
6
1
3
5
1
2
6
0
55
2
7
2
1
18
2
4
0
2
9
9
5
5
4
4
6
6
10
4
4
37
10
7
7
5
6
8
5
5
24
6
4
5
5
15
7
10
9
8
1.2E-02 4.3E-02
5.6E-04 8.3E-03
1.5E-08 3.6E-06
1.4E-02 4.5E-02
6.3E-05 1.8E-03
6.5E-04 8.5E-03
1.8E-02 4.9E-02
9.7E-03 3.7E-02
9.0E-03 3.6E-02
2.6E-10 9.2E-08
2.2E-04 4.5E-03
7.5E-03 3.4E-02
6.6E-03 3.2E-02
5.6E-03 3.0E-02
1.5E-02 4.5E-02
1.8E-02 4.9E-02
3.3E-03 2.3E-02
9.6E-03 3.7E-02
4.0E-04 6.7E-03
1.1E-02 4.0E-02
2.0E-06 2.0E-04
1.2E-03 1.2E-02
1.8E-02 4.9E-02
1.3E-07 2.3E-05
9.8E-03 3.7E-02
8.5E-04 1.1E-02
1.3E-03 1.2E-02
2.7E-03 2.0E-02
7.5E-05 1.9E-03
1.4E-02 4.4E-02
0.40
0.40
0.40
0.39
0.39
0.38
0.38
0.38
0.37
0.36
0.36
0.36
0.36
0.35
0.35
0.34
0.33
0.33
0.45
0.45
0.45
0.44
0.43
0.43
0.42
0.42
0.42
0.41
0.40
0.40
D11A
S01A
S01A
C05A
A01A
S01A
A07A
D07X
D10A
D11A
H02A
R01A
S01B
S02A
S03A
R03A
D06A
S03B
G01A
S01A
N03A
R01A
S01A
S02A
180
252
102
240
153
71
234
204
80
109
120
137
50
10
10
50
20
12
18
18
19
16
29
13
6
2
0
6
1
0
6
4
1
3
4
4
15
3
3
15
6
4
6
6
6
5
9
4
0.33
0.33
0.33
0.32
0.31
0.31
0.31
0.30
0.30
0.30
0.30
0.30
1.3E-02 4.4E-02
6.1E-04 8.4E-03
5.8E-04 8.4E-03
1.7E-02 4.8E-02
1.3E-02 4.3E-02
1.0E-02 3.8E-02
1.2E-02 4.1E-02
2.6E-03 2.0E-02
2.0E-03 1.7E-02
9.1E-03 3.6E-02
1.8E-04 3.9E-03
1.2E-03 1.2E-02
6
Supplementary Table 7 . Combination effects of predicted drug pairs on the growth of the human non-small cell lung cancer A549 cells.
Drug
Combinations
IMA + DOX
GEF + DOX
5FU + DOX
EPI + SUN
IMA + TET
CIS + TET
DOX + EPI
FLU + ETO
EPI + CAR
TET + DOX
DOC + FLU
EPI + SOR
DOX + CAR
ETO + CAR
EPI + IMA
CAR + FLU
BOR + 5FU
TET + BOR
5FU + FLU
GEF + 5FU
BOR + CAR
5FU + IMA
5FU + CAR
5FU + ETO
5FU + SUN
5FU + EPI
BOR + EPI
FLU + TET
DOX + SUN
ETO + DOX
EPI + CIS
CIS + SOR
BOR + FLU
DOX + FLU
GEF + SOR
FLU + CIS
EPI + FLU
CAR + SUN
ETO + SOR
FLU + SOR
FLU + VIN
VIN + CIS
CI Values at:
IC50 IC75 IC90 IC95
0.331 0.141 0.065 0.040
0.351 0.152 0.086 0.063
0.544 0.264 0.130 0.081
0.502 0.301 0.188 0.140
0.386 0.250 0.217 0.214
0.626 0.309 0.194 0.164
0.481 0.370 0.315 0.296
0.669 0.453 0.336 0.287
0.679 0.473 0.366 0.324
0.672 0.461 0.392 0.380
0.663 0.495 0.452 0.451
0.817 0.604 0.451 0.371
0.774 0.596 0.458 0.383
0.448 0.486 0.528 0.558
0.558 0.538 0.524 0.517
0.542 0.541 0.540 0.540
0.640 0.592 0.551 0.526
0.782 0.630 0.550 0.518
0.830 0.683 0.563 0.494
0.453 0.530 0.622 0.695
0.693 0.689 0.686 0.683
0.640 0.674 0.711 0.738
0.473 0.572 0.718 0.851
0.926 0.805 0.702 0.641
0.698 0.701 0.750 0.809
0.991 0.887 0.795 0.739
0.821 0.803 0.808 0.824
0.952 0.885 0.823 0.784
0.856 0.847 0.839 0.834
1.222 0.993 0.812 0.711
1.434 1.044 0.786 0.658
0.805 0.815 0.850 0.885
0.997 0.897 0.850 0.842
0.947 0.903 0.888 0.889
1.000 0.924 0.898 0.900
1.175 1.025 0.904 0.833
1.113 0.991 0.911 0.873
1.167 1.027 0.913 0.848
1.813 1.125 0.881 0.777
0.427 0.676 1.087 1.517
1.472 1.268 1.096 0.995
1.928 1.414 1.077 0.913
0.985 0.845
0.988 0
0.950 0.001
0.946 0.030
0.323 0.381
0.914 0.290
0.976 0.002
0.985 0.002
0.831 0
0.972 0.347
0.983 0.001
0.987 0.030
0.946 0.241
0.865 0
0.978 0.568
0.984 0
0.965 0
0.959 0.260
0.967 0
0.971 0
0.849 0
0.984 0.044
0.967 0
0.970 0
0.992 0
0.832 0
0.989 0
0.976 0.001
0.992 0.296
0.988 0.001
0.987 0.008
0.994 0.450
0.982 0.001
0.976 0.008
0.999 0
0.985 0.032
0.976 0.001
0.994 0.008
0.985 0.008
0.988 0.010
0.827 0.440
0.935 0.720
1'
1
4
1
1'
4
1
1'
1'
4
1
1'
1'
1
1'
1'
1'
1'
1
1'
1'
1'
1'
4
4
1'
1'
1'
1
1'
1'
1'
1'
1'
1
1'
1'
1'
1'
1'
4
1
Weighted
Average CI
Values
0.721
0.758
0.811
0.815
0.833
0.840
0.849
0.851
0.540
0.558
0.577
0.586
0.616
0.686
0.708
0.717
0.373
0.402
0.429
0.481
0.486
0.487
0.524
0.527
0.097
0.117
0.178
0.223
0.239
0.248
0.335
0.852
0.871
0.897
0.914
0.927
0.932
0.935
0.981
1.111
1.127
1.164
P
1
P
2
Quadrant
7
ETO + SUN
BOR + IMA
PAC + VIN
SOR + IMA
FLU + SUN
EPI + VIN
GEF + VIN
DOC + VIN
PAC + FLU
VIN + SOR
DOC + SOR
GEF + FLU
DOC + PAC
0.751 0.980 1.279 1.533
0.832 0.725 1.153 2.076
2.719 1.913 1.395 1.146
2.640 2.020 1.558 1.313
0.905 1.362 2.255 3.301
1.885 2.114 2.396 2.624
1.154 1.729 2.697 3.740
3.039 2.789 2.713 2.729
1.322 1.868 2.734 3.604
0.829 1.537 2.855 4.352
1.664 2.235 3.010 3.691
2.707 2.996 3.377 3.695
1.489 3.100 6.671 11.386
1.268
1.405
1.532
1.661
2.360
2.380
2.766
2.767
2.768
2.988
2.993
3.361
7.325
0.983 0.008
0.988 0.487
0.984 0.440
0.997 0.754
0.985 0.007
0.938 0.394
0.980 0.654
0.984 0.482
0.983 0
0.921 0.957
1.000 0.403
0.985 0.001
0.957 0
Supplementary Table 8 . Combination effects of predicted drug pairs on the growth of E. coli.
Drug
Combinations
CI Values at:
IC50 IC75 IC90 IC95
IMI + TRI
CIS + TRI
1.008 0.843 0.711 0.590
1.240 0.953 0.758 0.661
STR + TRI 1.176 0.963 0.792 0.695
CEF + ERY 1.138 0.962 0.823 0.697
CEF + AMO 0.982 0.899 0.827 0.782
ERY + SUL 1.004 0.930 0.861 0.818
TET + RIF 0.962 0.932 0.932 0.882
PEF + SUL 1.117 1.003 0.922 0.881
PEF + AMO 1.034 0.985 0.943 0.917
IMI + PEF 1.069 1.010 0.956 0.920
PEF + ERY 1.114 1.023 0.953 0.915
IMI + AMO 1.280 1.113 0.968 0.880
RIF + SUL 1.175 1.081 1.012 0.977
CIS + PEF 1.014 1.021 1.033 1.042
TET + PEF 1.122 1.081 1.049 1.031
IMI + SUL 1.354 1.167 1.025 0.948
CEF + STR 1.262 1.149 1.047 0.983
CEF + TRI 1.645 1.260 1.006 0.887
IMI + STR 1.095 1.095 1.095 1.096
TET + TRI 1.108 1.100 1.105 1.116
IMI + CEF 1.496 1.287 1.110 0.937
TET + CEF 0.991 1.052 1.122 1.175
PEF + STR 1.241 1.181 1.124 1.087
TET + SUL 1.354 1.228 1.115 1.046
TET + ERY 1.248 1.171 1.128 1.112
TET + AMO 1.174 1.161 1.148 1.139
ERY + TRI 1.385 1.253 1.136 1.064
RIF + TRI 1.291 1.221 1.159 1.119
STR + SUL 0.994 1.110 1.266 1.398
Weighted
Average CI
Values
0.964
0.968
0.993
1.028
1.032
1.055
1.056
1.063
1.073
1.095
0.718
0.806
0.826
0.832
0.839
0.872
0.915
0.941
0.950
1.109
1.115
1.116
1.133
1.134
1.142
1.149
1.155
1.169
1.260
P
1
P
2
Quadrant
0.761 0.001
0.892 0.001
0.836 0
0.997 0.504
0.990 0.001
0.934 0.062
1.000 0.918
0.876 0.011
1.000 0.118
0.989 0.012
0.939 0.364
0.999 0.122
0.572 0.286
0.837 0.016
0.970 0.475
0.561 0.004
0.997 0.162
0.677 0
0.958 0.457
0.935 0
0.975 0.006
0.986 0.737
0.996 0.020
0.745 0.045
0.935 0.002
0.973 0.756
0.939 0.002
0.736 0.187
0.636 0
1
4
1
4
1
1'
1
1
4
4
1'
1'
2
4
1
4
4
4
1
1'
1
1'
4
4
1'
1'
1
1
4
8
1'
2
1
1'
1'
1
1'
1
1
1
1'
1
1
TET + STR 1.394 1.342 1.294 1.263
AMO + SUL 1.221 1.250 1.310 1.367
RIF + IMI 1.291 1.305 1.321 1.332
ERY + STR 1.500 1.410 1.351 1.324
PEF + TRI 1.425 1.385 1.361 1.352
CEF + SUL 1.717 1.560 1.467 1.429
AMO + TRI 1.494 1.537 1.600 1.657
RIF + PEF 1.817 1.699 1.595 1.532
IMI + ERY 1.474 1.599 1.774 1.923
RIF + STR 1.265 1.528 1.847 2.100
RIF + AMO 1.399 1.684 2.027 2.300
RIF + CEF 1.655 1.887 2.171 2.402
AMO + STR 1.944 2.088 2.247 2.365
TET + IMI 2.094 2.335 2.605 2.808
ERY + AMO 2.242 2.461 2.783 3.316
1.301
1.312
1.319
1.367
1.369
1.495
1.600
1.613
1.769
1.826
2.005
2.155
2.232
2.581
2.878
0.945 0
0.610 0.012
0.783 0.351
0.924 0
0.984 0
0.628 0.003
0.650 0
0.730 0.481
0.995 0.532
0.987 0.730
0.681 0.350
0.725 0.351
0.994 0.208
0.991 0.808
0.996 0.412
4
1
1
4
4
1
1
1
1'
4
4
1'
1'
4
4
Supplementary Table 9 . Combination effects of predicted drug pairs on the growth of S. aureus.
Drug
Combinations
CI Values at:
IC50 IC75 IC90
TET + RIF 0.595 0.461
RIF + STR 0.385 0.412
RIF + TRI
IMI + TRI
0.543
0.561
0.460
0.538
PEF + AMO 0.551 0.595
RIF + IMI 0.722 0.677
PEF + STR 0.569 0.612
TET + ERY 0.693 0.672
IMI + AMO 0.625 0.634
RIF + PEF 0.577 0.629
RIF + AMO 0.642 0.664
TET + IMI 0.874 0.765
RIF + SUL 0.844 0.702
CEF + STR 0.663 0.703
TET + STR 0.537 0.640
TET + CEF 0.864 0.800
AMO + STR 0.677 0.725
CEF + TRI 0.669 0.716
IMI + CEF 1.032 0.940
IMI + SUL
EPI + TRI
EPI + TET
1.220
1.418
0.884
1.026
1.095
0.891
IMI + ERY 1.453 1.113
TET + AMO 0.662 0.777
EPI + CEF 1.151 1.058
TET + TRI 0.697 0.797
CEF + SUL 0.833 0.924
IC95
0.727
0.716
0.643
0.748
0.785
0.864
0.725
0.820
0.830
0.805
0.308
0.463
0.426
0.521
0.682
0.607
0.694
0.646
0.691
0.772
0.714
0.924
0.713
1.037
0.926
1.172
1.169
0.686
0.692
0.685
0.696
0.749
0.764
0.751
0.779
0.778
0.857
0.361
0.442
0.426
0.524
0.644
0.634
0.660
0.655
0.661
0.865
0.848
0.908
0.854
0.920
0.976
0.983
1.056
Weighted
Average CI
Values
0.680
0.691
0.703
0.733
0.746
0.757
0.762
0.774
0.776
0.870
0.383
0.439
0.444
0.529
0.640
0.641
0.655
0.659
0.664
0.895
0.901
0.909
0.909
0.912
0.990
0.993
1.053
P
1
P
2
1.000 0.918
0.987 0.730
0.736 0.187
0.761 0.001
1.000 0.118
0.783 0.351
0.996 0.020
0.935 0.002
0.999 0.122
0.730 0.481
0.681 0.350
0.991 0.808
0.572 0.286
0.997 0.162
0.945 0
0.986 0.737
0.994 0.208
0.677 0.000
0.975 0.006
0.561 0.004
0.855 0
0.943 0.511
0.995 0.532
0.973 0.756
0.930 0.000
0.935 0.000
0.628 0.003
Quadrant
1'
1
1
4
1'
4
4
1
4
1
1
4
1
1'
1
2
1
4
4
4
4
1
1
1
1'
1'
4
9
TET + PEF 0.996 1.005
IMI + PEF 1.102 1.121
ERY + AMO 1.242 1.177
AMO + TRI 0.812 0.969
ERY + TRI 1.168 1.211
ERY + SUL 1.452 1.381
PEF + ERY 1.466 1.469
TET + SUL 0.910 1.090
CEF + AMO 0.700 1.081
STR + SUL 1.580 1.494
IMI + STR 1.044 1.378
STR + TRI 2.187 2.040
RIF + CEF 1.116 1.561
PEF + TRI 2.038 2.262
ERY + STR 1.867 2.969
2.185
2.561
4.781
PEF + SUL 8.239 7.438 6.890
AMO + SUL 3.595 10.705 32.737
CEF + ERY 1.372 2.597 4.916
1.056
1.144
1.146
1.174
1.302
1.444
1.488
1.478
1.684
1.692
1.819
1.916
1.112
1.162
1.141
1.346
1.397
1.555
1.509
1.901
2.288
1.945
2.199
1.843
2.746
2.806
6.652
6.588
70.656
7.586
1.062
1.142
1.160
1.166
1.308
1.477
1.490
1.513
1.707
1.742
1.805
1.939
2.178
2.547
4.876
7.014
40.584
5.166
0.970 0.475
0.989 0.012
0.996 0.412
0.650 0
0.939 0.002
0.934 0.062
0.939 0.364
0.745 0.045
0.990 0.001
0.636 0
0.958 0.457
0.836 0
0.725 0.351
0.984 0
0.924 0
0.876 0.011
0.610 0.012
0.997 0.504
Supplementary Table 10 . Table list of all drugs used in this study, their abbreviation, therapeutic class and mechanism of action.
Drug Name Abbreviation Class Mechanism of action
4
1'
4
1
4
1
1'
1
4
1'
1'
1
4
4
1
4
1'
1'
Docetaxel
Paclitaxel
Cisplatin
Carboplatin
Fludarabine
Epirubicin
Etoposide
DOC
PAC
CIS
CAR
FLU
EPI
ETO
Antimicrotubule agent
Antimicrotubule agent
Cross-linking reagent
Cross-linking reagent
DNA synthesis inhibitor
Inhibits the microtubule network
Inhibits the microtubule network
Inhibits DNA synthesis
Inhibits DNA synthesis
Inhibits DNA polymerase alpha, ribonucleotide reductase and DNA primase
Inhibits activity of topoisomerase II and
DNA helicase
Inhibits DNA topoisomerase II
Doxorubicin
5-Fluorouracil
Bortezomib
Gefitinib
Sorafenib
Imatinib
Sunitinib
Vinblastine
Ceftazidime
DOX
5FU
BOR
GEF
SOR
IMA
SUN
VIN
CEF
Nucleic acid and protein synthesis inhibitor
Nucleic acid synthesis inhibitor
Nucleic acid synthesis inhibitor
Nucleic acid synthesis inhibitor
Proteasome inhibitor
Protein kinase inhibitor
Protein kinase inhibitor
Protein kinase inhibitor
Protein kinase inhibitor
Tubulin modulator
Inhibits DNA topoisomerase II
Inhibits the thymidylate synthetase
Inhibits the 26S proteasome
Inhibits EGFR tyrosine kinase
Interacts with multiple intracellular and cell surface kinases
Inhibits the Bcr-Abl tyrosine kinase
Inhibits multiple RTKs binds to the microtubular proteins of the mitotic spindle
Inhibits penicillin binding protein 3
Imipenem IMI
Cell wall synthesis inhibitor
Cell wall synthesis Inhibits pencillin binding proteins
10
Amoxicillin
Trimethoprim
Sulfamethoxazole SUL
Pefloxacin
Rifampin
Tetracycline
Erythromycin
Streptomycin
AMO
TRI
PEF
RIF
TET
ERY
STR inhibitor
Cell wall synthesis inhibitor
Folic acid synthesis
Inhibits penicillin-binding protein 1A
Inhibits dihydrofolate reductase inhibitor
Folic acid synthesis inhibitor
Nucleic acid synthesis inhibitor
Inhibits dihydrofolate synthetase
Inhibits activity of DNA gyrase and topoisomerase IV
Nucleic acid synthesis inhibitor
Inhibits RNA polymerase activity
Protein synthesis inhibitor Inhibits binding of aminoacyl t-RNA
Protein synthesis inhibitor Inhibits translocation of peptidyl t-RNA
Protein synthesis inhibitor Inhibits binding of formylmethionyl t-RNA
Supplementary Table 11 . In vitro experimental validation
Model Effective Ineffective Prediction accuracy
Anti-bacterial ( S. Aureus, E. coli ) 38 9 0.81 (38/47)
Anti-cancer (A549)
Total
39
77
16
25
0.71 (39/55)
0.75
Materials
(PPI) data were assembled from multiple sources. including Biomolecular Interaction Network Database (BIND)
Molecular INTeraction database (MINT) (Zanzoni, et al., 2002), Mammalian Protein-Protein Interaction
Chemical (ATC) codes of drugs were extracted from DrugBank (Knox, et al., 2011).
Database building and evaluation
To systematically identify effective drug pairs, we combined drug combination data from multiple sources
Importantly, we included information about drug side effects, target proteins and associated diseases, as this
11
information is often critical for determining whether a drug combination is practical or not. In addition, we also
UDDIs are defined as those interactions in which two drugs can interact to cause an adverse effect, such as the increase of toxicity or the decrease of effect. To our knowledge, PreDC database is currently the world's largest database of drug combinations either approved by FDA or validated by in vitro or in vivo experiments.
To evaluate the database quality, the chemical and disease diversities were calculated and further
of chemical space of PreDC database is not statistically significantly different from Drugbank (Supplementary
Figure 2a, p = 0, Kolmogorov –Smirnov test), which indicates that the PreDC database is sufficiently large enough to cover diverse chemical spaces. In addition, the radar chart analysis shows that the diseases in
PreDC concentrate on four major classes: i.e., C04 - neoplasms, C10 - nervous system diseases, C01 - bacterial infections and mycoses, and C14 - cardiovascular diseases (Supplementary Figure 2b, blue line), which are very similar to Drugbank (Supplementary Figure 2b, green line). All these indicate that PreDC database is chemically and pharmacologically diverse, so as to ensure the generation of predictive models with reliable performance and generalization ability.
Disease distribution analysis
Figure 3a shows the disease distribution changing with P
1
and P
2
. The results show that, with the increasing of P
2
, there's a clear downward trend for the numbers of the four major groups of diseases, corresponding to the numbers of drug combinations. Importantly, when P
2
is in a small range of 0.0~0.2, the anti-cancer drug combination gets the most votes that has demonstrated therapeutic benefit in clinical trials (about 68% in all anti-cancer combinations), followed by cardiovascular disease (52%), infections (37%) and nervous system disease (39%). While in the range of 0.8~1.0, the cancer treatment is the lowest in number (5%), and the infection disease treatment (22%) makes up the greatest percentage of all combinations. It is known that most
severe side effects when combined together (large P
2
). In this context, the identification of drugs which show weak negative interaction with a specific drug with strong cytotoxicity has been a high priority. One means to achieve this is to combine them with drugs of mild lethality such as the anti-infections drugs, although their P
2 is possibly high (with high tendency of producing adverse effects). It is found that nearly 77% of the diseases are distributed in the range of 0.8~1 of P
1
, which is consistent with the fact that the majority of existing drug combinations are located in the regions with high P
1
value. All these demonstrate that the two quantitative standards provided by PEA can clearly distinguish the effective drug combinations and undesirable drug-drug interactions.
12
Association of diseases for drug combinations
For novel drug combinations, we inferred their indications based on their similarity to the known drug combinations and the known drug combination –disease associations. The drug combination which has the largest LR value to the query drug pair is regarded as a reference and its indications are then assigned to the novel drug combination.
Looking specifically at the 3269 optimal drug combinations, we acquire 3614 drug combination –disease associations, among which the neoplasms (C04) are the most common class of diseases that are related to
712 drug pairs (21.8% of all drug pairs), followed by the bacterial infections and mycoses (C01) (648, 19.8%), nervous system diseases (C10) (428, 13.1%) and cardiovascular diseases (C14) (353, 10.8%) (Figure 4c).
This is in good agreement with the interest of current combination therapies for complex and chronic
diseases(Woodcock, et al., 2011).
To validate these new associations, we used an independent benchmark dataset as mentioned above to compute the disease similarity between our predictions and corresponding diseases derived from literature.
We first mapped all diseases to the relevant Medical Subject Heading (MeSH) concepts manually, and then
Semantic Measures Library and ToolKit (SML-Toolkit)(Harispe, et al., 2014). We used 10
4 random same-size set of diseases to generate a background distribution for comparison. The significance of difference was computed using a Wilcoxon ranked sum test, which is equivalent to the Mann-Whitney U-test.
Compared to random similarity distribution (mean = 0.16), we found a much more significant similarity
(mean = 0.56) between our predictions and the benchmark datasets ( p = 8.6×10 -61 , Wilcoxon ranked sum test,
Supplementary Figure 3). In addition, the present experiment also shows that 81% predicted antibacterial drug pairs are effective against S. aureus or E. coli models, and 71% predicted to treat cancer are effective against the A549 cells. These results suggest that it is a feasible way to explore the indications of a novel drug pair by the extended PEA model. The full list of predicted indications for the 3269 optimal combinations is available in the PreDC database (http://sm.nwsuaf.edu.cn/lsp/predc.php).
In vitro experimental validation
15 antitumor drugs were obtained from Shanghai Biochempartner Co., Ltd. (Shanghai, China). 10 antibiotics were purchased from Nanjing Zelang Medical Technology Co., Ltd. (Nanjing, China). Supplementary Table 10 lists the detailed information for all 25 drugs including their therapeutic class and mode of action. Antibiotics stock solutions were stored in the dark at -20
℃
, and were thawed and diluted in sterilized broth for experimental use. All antitumor drugs were freshly prepared when used. All experiments were conducted with
13
the standard reference strains Gram-negative Escherichia coli ( E. coli ) ATCC 25922 and Gram-positive
Staphylococcus aureus ( S. aureus ) ATCC 29213 (for antibacterial experiments) and Non-small cell lung cancer (NSCLC) line A549/ATCC (for antitumor experiment). S. aureus , E. coli and A549 cell lines were kindly provided by Prof. Jinyou Duan from NWSUAF, Yangling, China.
The A549 cell lines were grown as monolayer cultures in RPMI medium 1640 (Hyclone) supplemented with
10% FBS, 100 U/mL penicillin, and 100 μg/mL streptomycin at 37°C in 5% CO2/95% air, and were harvested with trypsin/EDTA when they were in the logarithmic phase of growth. Cytotoxic effects of drugs on cells were determined by the MTT assay. Briefly, 100 μL cells were plated at a density of 2000-4000 cells per well in
96-well plates. Following 24h incubation, cells were treated with a serial fivefold dilution of drug in growth medium to give 8 concentrations and cultivated for 72h. After incubation for specified times at 37°C in a humidified incubator, 20 μL of MTT (5 mg∕mL in PBS) were added to each well, and cells were incubated for a fu rther 4 h. After removal of the medium, 100 μL DMSO was added to each well. The absorbance was recorded on a microplate reader (DNM-9602, Beijing Pulang new technology Co., LTD. Beijing, China) at the wavelength of 490 nm. Each experiment was performed in sextuplicate for each drug concentration and was independently performed 2 or 3 times.
S. aureus/E. coli cells were inoculated into trypticase-soy broth (TSB) and incubated to exponential growth at 37
℃
. The growth density was adjusted to match an optical density at 600 nm (OD
600
) of about 0.1 (1×10 8 cfu/ml). Afterwards, a 1:200 dilution was prepared in a fresh TSB and used as the inoculum (≈5×10 5 cfu/ml).
We then transferred 180 μL cells plus medium to 96-well plates and to each well we added 20 μL of drugs with the desired concentrations. In the presence of the drugs, we grew the cells for 6 h at 37°C. Antimicrobial activity was determined by measuring the absorbance at 600 nm using a microplate reader (DNM-9602,
Beijing Pulang new technology Co., LTD. Beijing, China).
Median IC
50
values of each drug were first obtained using the antitumor and antibacterial assays as described above. Next, each drug was added at a 1:1 ratio based on their IC
50
values to create a mixture of combination drugs. Each experiment was performed in sextuplicate for each drug concentration and was independently performed 2 or 3 times. Combination effects were evaluated by identifying the combination
index (CI) as described by Chou and Talalay(Chou and TaLaLay, 1981).
CI
(
D
D x
)
1
1
(
D
D x
)
2
2
(1)
In the denominator, ( D x
)
1 and ( D x
)
2 are the concentration of two agents that individually achieve x % inhibition of a system. In the numerators, ( D )
1
+( D )
2
“in combination” also inhibit x %. CI < 1, = 1, and > 1 indicate the synergistic, additive, or antagonistic effect, respectively. In this analysis, because the high degrees of effects
14
are more important to the chemotherapy than the low degrees of effects, the weighted CI value was designed as CI wt
= (CI
50
+ 2CI
75
+ 3CI
90
+ 4CI
95
)/10 to quantify the combination effects. For infection and cancer models, the additive and synergistic drug combinations are thought to be therapeutically effective on diseases.
In total, we examined 102 novel predicted drug pairs, resulting in the confirmation of 77 effective combinations (~75% of all tested drug pairs) (Supplementary Table 11).
In the cancer model, we examined 55 predicted drug pairs against the human non-small cell lung cancer
A549 cells. Resultantly, 39 of these pairs are found effective (~71% accuracy), among which 34 cases are synergistic and 5 are additive (Supplementary Table 7 and 11). The drug pair with the greatest synergy is bortezomib + 5-fluorouracil (quadrant 1'; CI = 0.097), followed by bortezomib + tetracycline (quadrant 1; CI =
0.12), 5-fluorouracil + Fludarabine (quadrant 1'; CI = 0.18), Gefitinib + 5-fluorouracil (quadrant 1'; CI = 0.22), etc. These potent combinations are demonstrated promising for treatment of the lung cancer. More interestingly, we find that some drugs, so called promiscuous drugs, are inherently more likely to participate in the synergistic combinations. One example is epirubicin, which partakes in the effective combination with all the tested drugs (except vinblastine) against cancer cells. Indeed, intrinsic promiscuity of combinational drugs
may be the dominant factor in drug synergy(Cokol, et al., 2011).
For anti-bacterial model, 47 drug pairs were tested by S. aureus and E. coli . We validate that 38 pairs (~81% of all 47 antibacterial pairs) are effective (Supplementary Table 8, 9 and 11). Among them, 9 drug pairs exhibit activities (synergy or additivity) against both bacterial species. Examples include imipenem + trimethoprim
(quadrant 4; CI = 0.53 for S. aureus and 0.72 for E. coli ) and tetracycline + rifampin (quadrant 2; CI = 0.38 for S. aureus and 0.92 for E. coli ). These combinations may be used as antibacterial combinations with a broad spectrum of antimicrobial activity. Remaining combinations exert effects exclusively on one particular species:
S. aureus and E. coli are uniquely susceptible to 17 and 8 drug pairs, respectively. For example, S. aureus exhibits unique synergistic susceptibilities to rifampin in combination with streptomycin (quadrant 1; CI = 0.43) and trimethoprim (quadrant 4; CI = 0.44), while E. coli . is susceptible to the combinations of streptomycin and trimethoprim (quadrant 4; CI = 0.83) and of ceftazidime and erythromycin (quadrant 1; CI = 0.83). These drug pairs can only treat either Gram-positive or Gram-negative infections.
It should be noted that these in vitro assessments do not consider the potential adverse effects of the drug combinations, especially those drug pairs with high P
2
values, which must be evaluated through further appropriate clinical trials. For example, the combination of rifampin and tetracycline has been proved to be active against S. aureus (quadrant 2; CI = 0.44) in our antimicrobial assays, but its concomitant therapy might be restricted because rifampin, which, as a potent inducer of the hepatic microsomal system, might reduce the serum concentrations of tetracycline in vivo .
Nevertheless, these results confirm that our systematic
15
computational screening has sufficient accuracy and sensitivity to provide a wealth of novel hypotheses that can drive discovery of drug combinations.
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, et al.
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, et al.
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,
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Higher ‐ Order Kinetic Systems with Two or More Mutually Exclusive and Nonexclusive Inhibitors, Eur. J. Biochem.
,
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, et al.
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, et al.
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, et al.
(2009) Mechanisms of drug combinations: interaction and network perspectives, Nat Rev Drug Discov ,
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Knox, C.
, et al.
(2011) DrugBank 3.0: a comprehensive resource for ‘omics’ research on drugs, Nucleic Acids Res.
,
39 , D1035-D1041.
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, et al.
(2010) DCDB: drug combination database, Bioinformatics , 26 , 587-588.
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,
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, et al.
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, 40 , D1128-D1136.
Chari, R.V. (2007) Targeted cancer therapy: conferring specificity to cytotoxic drugs, Acc. Chem. Res.
, 41 , 98-107.
Chou, T.C. and TaLaLay, P. (1981) Generalized Equations for the Analysis of Inhibitions of Michaelis
‐
Menten and
Higher ‐ Order Kinetic Systems with Two or More Mutually Exclusive and Nonexclusive Inhibitors, Eur. J. Biochem.
,
115 , 207-216.
Cokol, M.
, et al.
(2011) Systematic exploration of synergistic drug pairs, Mol. Syst. Biol.
, 7 .
Jia, J.
, et al.
(2009) Mechanisms of drug combinations: interaction and network perspectives, Nat Rev Drug Discov ,
8 , 111-128.
Knox, C.
, et al.
(2011) DrugBank 3.0: a comprehensive resource for ‘omics’ research on drugs, Nucleic Acids Res.
,
39 , D1035-D1041.
Liu, Y.
, et al.
(2010) DCDB: drug combination database, Bioinformatics , 26 , 587-588.
Woodcock, J., Griffin, J.P. and Behrman, R.E. (2011) Development of novel combination therapies, N. Engl. J. Med.
,
364 , 985-987.
Zhu, F.
, et al.
(2012) Therapeutic target database update 2012: a resource for facilitating target-oriented drug discovery, Nucleic Acids Res.
, 40 , D1128-D1136.
Chari, R.V. (2007) Targeted cancer therapy: conferring specificity to cytotoxic drugs, Acc. Chem. Res.
, 41 , 98-107.
Chou, T.-C. (2006) Theoretical basis, experimental design, and computerized simulation of synergism and antagonism in drug combination studies, Pharmacol. Rev.
, 58 , 621-681.
Chou, T.C. and TaLaLay, P. (1981) Generalized Equations for the Analysis of Inhibitions of Michaelis ‐ Menten and
Higher ‐ Order Kinetic Systems with Two or More Mutually Exclusive and Nonexclusive Inhibitors, Eur. J. Biochem.
,
115 , 207-216.
Cokol, M.
, et al.
(2011) Systematic exploration of synergistic drug pairs, Mol. Syst. Biol.
, 7 .
Jia, J.
, et al.
(2009) Mechanisms of drug combinations: interaction and network perspectives, Nat Rev Drug Discov ,
8 , 111-128.
Knox, C.
, et al.
(2011) DrugBank 3.0: a comprehensive resource for ‘omics’ research on drugs, Nucleic Acids Res.
,
39 , D1035-D1041.
Liu, Y.
, et al.
(2010) DCDB: drug combination database, Bioinformatics , 26 , 587-588.
Woodcock, J., Griffin, J.P. and Behrman, R.E. (2011) Development of novel combination therapies, N. Engl. J. Med.
,
364 , 985-987.
18
Zhu, F.
, et al.
(2012) Therapeutic target database update 2012: a resource for facilitating target-oriented drug discovery, Nucleic Acids Res.
, 40 , D1128-D1136.
Chari, R.V. (2007) Targeted cancer therapy: conferring specificity to cytotoxic drugs, Acc. Chem. Res.
, 41 , 98-107.
Chou, T.-C. (2006) Theoretical basis, experimental design, and computerized simulation of synergism and antagonism in drug combination studies, Pharmacol. Rev.
, 58 , 621-681.
Cokol, M.
, et al.
(2011) Systematic exploration of synergistic drug pairs, Mol. Syst. Biol.
, 7 .
Jia, J.
, et al.
(2009) Mechanisms of drug combinations: interaction and network perspectives, Nat Rev Drug Discov ,
8 , 111-128.
Knox, C.
, et al.
(2011) DrugBank 3.0: a comprehensive resource for ‘omics’ research on drugs, Nucleic Acids Res.
,
39 , D1035-D1041.
Liu, Y.
, et al.
(2010) DCDB: drug combination database, Bioinformatics , 26 , 587-588.
Woodcock, J., Griffin, J.P. and Behrman, R.E. (2011) Development of novel combination therapies, N. Engl. J. Med.
,
364 , 985-987.
Zhu, F.
, et al.
(2012) Therapeutic target database update 2012: a resource for facilitating target-oriented drug discovery, Nucleic Acids Res.
, 40 , D1128-D1136.
Chari, R.V. (2007) Targeted cancer therapy: conferring specificity to cytotoxic drugs, Acc. Chem. Res.
, 41 , 98-107.
Jia, J.
, et al.
(2009) Mechanisms of drug combinations: interaction and network perspectives, Nat Rev Drug Discov ,
8 , 111-128.
Knox, C.
, et al.
(2011) DrugBank 3.0: a comprehensive resource for ‘omics’ research on drugs, Nucleic Acids Res.
,
39 , D1035-D1041.
Liu, Y.
, et al.
(2010) DCDB: drug combination database, Bioinformatics , 26 , 587-588.
Woodcock, J., Griffin, J.P. and Behrman, R.E. (2011) Development of novel combination therapies, N. Engl. J. Med.
,
364 , 985-987.
Zhu, F.
, et al.
(2012) Therapeutic target database update 2012: a resource for facilitating target-oriented drug discovery, Nucleic Acids Res.
, 40 , D1128-D1136.
Chari, R.V. (2007) Targeted cancer therapy: conferring specificity to cytotoxic drugs, Acc. Chem. Res.
, 41 , 98-107.
Jia, J.
, et al.
(2009) Mechanisms of drug combinations: interaction and network perspectives, Nat Rev Drug Discov ,
8 , 111-128.
Knox, C.
, et al.
(2011) DrugBank 3.0: a comprehensive resource for ‘omics’ research on drugs, Nucleic Acids Res.
,
39 , D1035-D1041.
Liu, Y.
, et al.
(2010) DCDB: drug combination database, Bioinformatics , 26 , 587-588.
Zhu, F.
, et al.
(2012) Therapeutic target database update 2012: a resource for facilitating target-oriented drug discovery, Nucleic Acids Res.
, 40 , D1128-D1136.
Jia, J.
, et al.
(2009) Mechanisms of drug combinations: interaction and network perspectives, Nat Rev Drug Discov ,
8 , 111-128.
Knox, C.
, et al.
(2011) DrugBank 3.0: a comprehensive resource for ‘omics’ research on drugs, Nucleic Acids Res.
,
39 , D1035-D1041.
Liu, Y.
, et al.
(2010) DCDB: drug combination database, Bioinformatics , 26 , 587-588.
Zhu, F.
, et al.
(2012) Therapeutic target database update 2012: a resource for facilitating target-oriented drug discovery, Nucleic Acids Res.
, 40 , D1128-D1136.
19