Nilotinib is a positive hit in a cellular MALDI-TOF MS
drug discovery screen and inhibits inflammation in response to LPS.
(A) Inhibition of the TLR2 and TLR4 signaling pathways. MRT68601 inhibits
TBK1 (TANK-binding kinase-1), which blocks production of type I interferons
(IFNs). NG-25 inhibits TAK1 (TGF-beta-activated kinase-1), which induces
TNF-α and IL-6 production. BI2536 inhibits BET proteins (bromodomain
and extra-terminal motif proteins), which are required for pro-inflammatory
gene transcription. (B) TNF-α secretion of THP-1 cells treated
in either vehicle control-treated (DMSO), 100 ng/mL LPS-treated, or
pre-treated with 5 μM NG-25, BI2536 or 1 μM MRT68601 for
1 h before 100 ng/mL LPS treatment for up to 24 h measured by ELISA.
(C) MALDI-TOF MS relative quantitation of the normalized ratio m/z 4964/4632 in THP-1 cells as treated in panel (B). (D)
PCA of all features identified by the MALDI-TOF MS of experiment in
panel (B) and 0.5 μM staurosporine-treated cells serving as
control for apoptotic cells. (E) Compound hit map of the mean of three
biological replicates with a 40% effectiveness cutoff showing nilotinib
and NG-25 as positive hits and imatinib as the negative hit (arrows).
(F) MALDI-TOF MS relative quantitation of the normalized ratio m/z 4964/4632 in THP-1 cells in vehicle control-treated
(DMSO), 100 ng/mL LPS-treated, or pre-treated with 5 μM nilotinib,
imatinib, 1 μM dasatinib, bosutinib, or ponatinib for 1 h before
100 ng/mL LPS-treatment for up to 24 h. (G) TNF-α secretion
of cells treated as in panel (F) measured by ELISA after 24 h. Significant
differences between two groups were determined by a Mann–Whitney
U-test. The statistical significance of the comparisons with LPS is
indicated as follows: ns, not significant; *, P ≤
0.05; **, P ≤ 0.01; ***, P ≤ 0.001. Error bars represent the standard deviation of four
biological replicates.