Fig. 1

Niclosamide potentiates anti-PD-L1 efficacy in vitro. a The Cytotoxicity of niclosamide on different human cancer cells. Above assay were determined by MTT as described in materials and methods. Each point represents the mean ± standard deviations (SDs) of three independent experiments performed. b-e T cell cytotoxicity test by colony formation assay. The survival of niclosamide pretreated H460 and A549 cells, un-pre-treated cells, treated with PD-L1 Ab or without, and co-cultured with PBMCs (targeted cells: effector cells = 1:0, 1:1, 1:4, 1:16) in 24-well plates for 4 days was estimated. Colonies were visualized by Giemsa staining. Survival relative to control is shown. f-i The effect of different treatments on CD4+ and CD8+ populations among CD3+ T cells. Results are presented as means ± S.D. of a representative experiment performed in triplicate. j-k Intracellular cytokine staining of granzyme B in T cell-mediated tumor cell killing assay in niclosamide-pretreated H460 and A549 cells and un-pre-treated cells, treated with PD-L1 Ab or without. l-m Intracellular cytokine staining of TNF-α in T cell-mediated tumor cell killing assay in niclosamide-pretreated and un-pre-treated H460 and A549 cells, treated with PD-L1 Ab or without. Results are presented as means ± S.D. of a representative experiment performed in triplicate. * P < 0.05, ** P < 0.01, *** P < 0.001