doi:10.1007/s12250-019-00145-w

Name	Cell-type	Signal to background ratio (SBR)^a
Name	Cell-type	NA^b	CCL2^c	CXCL10^c	IL-8^c	IL-6^c
A549	Lung epithelial cell line	2.3±0.5	1.6±0.1	1.5±0.3	1.9±0.1	3.6±0.1
THP-1	Monocyte cell line	5.8±2.1	3.2±0.7	1.7±0.2	2.0±0.2	1.2±0.1
iTHP-1^d	Macrophage-like cell	1.5±0.6	1.4±0.2	3.4±0.2	1.2±0.1	1.1±0.1
U937	Monocyte cell line	7.3±1.1	16.2±2.5	23.6±3.3	17.9±2.3	13±3.7
iU937^d	Macrophage-like cell	2.4±0.7	1.1±0.1	2.5±0.2	1.2±0.2	1.6±0.2
HL-60	Promyeloblast	6.1±0.6	13.0±2.7	1.2±0.2	4.4±0.1	1.3±0.3
iHL-60^e	Neutrophil-like cell	4.1±0.4	1.4±0.3	1.0±0.1	2.2±0.3	13.2±2.6
^aCells were incubated with 0.1 MOI of A/PuertoRico/8/1934 (H1N1) influenza virus and tested for the signal to background ratios (SRBs) at 48 h post infection. The SBR was calculated from the fluorescence value of the infected wells (signal) divided by the uninfected control wells (background) for each assay. ^b NA (neuraminidase), measured by neuraminidase activity assay, represents the replication level of the influenza virus. ^cCytokine expression was measured by AlphaLISA. ^diU937 and iTHP-1 cells were prepared from U937 and THP-1 cells induced by 100 ng/mL TPA for 24 h. ^eiHL-60 was prepared from HL-60 induced by 1.25% DMSO for 5 days.

Table 1. Identification of U937 cell line as a cell-based model for drug discovery against cytokines induced by influenza virus infection.

Chemical name	CC₅₀^a	IC₅₀^b NA	SI^d NA	IC50^c CCL2	IC50^c CXCL10	SI^d CCL2	SI^d CXCL10	Target and possible mechanisme	In vivo ^f	References^g
Ibrutinib	26.5	–^h	–	0.62	0.96	42.7	27.6	TPK inhibitor	+ⁱ	Florence et al.(2018)
Vorapaxar	> 80	–	–	5.2	13.3	> 15.4	> 6	PAR1 antagonist	+	Khoufache et al.(2013)
Ozanimod	26	–	–	7.7	10.7	3.4	2.4	S1PR1 agonist	+	Teijaro et al. (2011)
Ascomycin	62	21.3	2.9	8.1	9.9	7.7	6.3	Macrolides antibiotics	+	Sato et al. (1998)
Ribavirin	> 160	26.2	> 6.1	–	–	–	–	Anti-influnenza	+	Smee et al. (2008)
Oseltamivir	> 100	0.58	> 172.4	–	–	–	–	Anti-influnenza	+	Tsai et al. (2015)
Rosiglitazone	> 100	–	–	–	–	–	–	PPARγ agonist	+	Moseley et al.(2010)
Etoricoxib	> 50	–	–	–	–	–	–	COX-2 inhibitor	±^j	Zheng et al. (2008)
Ibuprofen	> 50	–	–	–	–	–	–	COX non-selective inhibitor	±	Lauder et al. (2011)
^aCC₅₀: 50% cytotoxic concentration (μmol/L) determined by MTS assay. ^bNA IC₅₀: 50% inhibition concentration (μmol/L) determined by NA activity assay. ^cCCL2/CXCL10 IC₅₀: 50% inhibition concentration (μmol/L) determined by AlphaLISA. ^dSI (Selective Index): a ratio of CC₅₀/ IC₅₀. ^eTarget and possible mechanism attributed to the compound as stated on either its "label" or literature. ^fIn vivo: the protective effect of mice from lethal influenza infection. ^gRef.: the reference of the reported protection effect of antiviral or immunomodulation agents in vivo. ^h"–": lower than 50% inhibition or not effective. ⁱ"+": Agent used alone can protect mice against lethal influenza virus infection according to the literature. ^j"±": Agent is effective in combination therapy, but when used alone cannot protect mice against lethal influenza virus infection.

Table 2. Validation of U937 cell model with a panel of antiviral and immunomodulatory agents.

Chemical name	IC₅₀ CCL2	IC₅₀ CXCL10	CC₅₀	SI CCL2	SI CXCL10	Approved of intended use	Possible mechanism and target
Dasatinib	0.63	0.71	> 90	> 142.9	> 126.8	Antineoplastic	Tyrosine-protein kinases inhibitor
Pitavastatin	0.85	0.87	> 90	> 105.9	> 103.4	Antilipemic HMG-CoA	reductase inhibitor
Simvastatin	1.16	1.75	66.8	57.6	38.2	Antilipemic HMG-CoA	reductase inhibitor
Fluvastatin	2.43	2.95	> 90	> 37.0	> 30.5	Antilipemic HMG-CoA	reductase inhibitor
Protriptyline	2.23	3.15	> 90	> 40.4	> 28.6	Antidepressant	Serotonin reuptake inhibitor
Levofloxacin	8.94	3.12	> 90	> 10.1	> 28.8	Antibiotic	DNA gyrase and topoisomerase IV inhibitor

Table 3. Six compounds were confirmed to inhibit influenza-induced CCL2/CXCL10 expression in U937 cell model.