Fig. 3

Pharmacological inhibition of NAMPT by FK866 or NAMPT knockdown reduces the NAD⁺ levels and cell viability of CRC cell lines. The viability assays of LoVo (a) or RKO (b) cells treated with 2% DMSO, FK866 (10 nM), NMN (100 μM), or NMN (100 μM) + FK866 (10 nM) for 3 days. The data are presented as the mean ± SD of three independent experiments. Student’s t-test was used for statistical analysis. c The viability of LoVo cells treated with shCtrl + 2% DMSO, shNAMPT + 2% DMSO, shNAMPT + NMN (100 μM) for 5 days. The data are presented as the mean ± SD of three independent experiments. Student’s t-test was used for statistical analysis. d Representative images of the colony formation and cell apoptosis assays using LoVo cells treated with 2% DMSO, FK866 (10 nM), or NMN (100 μM) + FK866 (10 nM). e The bar graphs show the quantification of the colony formation and cell apoptosis assay data. The data are presented as the mean ± SD of three independent experiments. Student’s t-test was used for statistical analysis. f The expressions of NAMPT and Ki-67 in LoVo cells treated with 2% DMSO, FK866 (10 nM), or NMN (100 μM) + FK866 (10 nM) for 3 days were analyzed by immunofluorescence staining. The scale bar (white) indicates 20 μm. The quantification of NAMPT and Ki-67 expression are presented as the mean ± SD of three independent experiments. Student’s t-test was used for statistical analysis. g The NAD⁺ levels of LoVo or RKO cells treated with 2% DMSO, FK866 (10 nM), NMN (100 μM), or NMN (100 μM) + FK866 (10 nM) for 3 days. The intracellular levels of NAD⁺ were measured using the NAD+/NADH Quantification Kit. The data are presented as the mean ± SD of three independent experiments. Student’s t-test was used for statistical analysis. h The NAD⁺ levels of LoVo cells treated with shCtrl + 2% DMSO, shNAMPT + 2% DMSO, shNAMPT + NMN (100 μM) for 5 days. The data are presented as the mean ± SD of three independent experiments. Student’s t-test was used for statistical analysis. * P < 0.05, ** P < 0.01, *** P < 0.001, and **** P < 0.0001 compared with the control group