Fig. 1: Cell proliferation assay and secretome profiling of oleate-treated and untreated HepG2 cells.

a, b MTT assays for measuring proliferation of HepG2 cells after treatment with different concentrations (50, 100, 250, 500, and 1000 μM) of oleate (a) and after cotreatment with palmitate (500 μM) and oleate (0, 100, 250, or 500 μM) (b). The data are shown as the mean ± SEM (n = 4). *P < 0.05 by Student’s t-test. The dashed line denotes the threshold of relative proliferation = 1. c An overall scheme for the secretome profiling. HepG2 cells were subjected to serum starvation for 12 h and then treated with oleate (500 μM). Oleate-treated (n = 4) and untreated (n = 4) samples were incubated for 24 h with conditioned media, and supernatants from the conditioned media were collected for sample preparation. LC-MS/MS analyses were performed for Peptide samples from oleate-treated and untreated samples with three technical replicates. The resulting LC-MS/MS datasets were analyzed using PE-MMR analysis, MS-GF + search, and AMT DB analysis for identification, assignment, and alignment of UMCs (see text)