HepG2 cells were transfected with FMO3 cDNA (black bars), or eGFP cDNA (white bars) as control. Cells were incubated in the absence or presence of 0.75mM palmitate. Cell lysates were subjected to immunoblotting to determine FMO3 expression and changes in eIF2α phosphorylation, XBP-1s, JNK1/2 phosphorylation, and cleaved caspase 3 levels. Representative immunoblots from 4 independent experiments (A) and the mean ± SEM of densitometric analysis are shown (B–E). Alternatively, gene expression was analyzed by qRT-PCR, and mRNA levels expressed as mean fold change of the level in untreated control cells ± SEM (F–L). Changes in cell viability in response to palmitate treatment and FMO3 expression were determined by 2H-tetrazolium, 2-(4,5-dimethyl-2-thiazolyl)-3,5-diphenyl bromide (MTT) assay (M). Student's t test; *, P < .05; **, P < .01; ***, P < .001 vs untreated hepatocytes; ##, P < .01; ###, P < .001 vs palmitate-treated eGFP-expressing hepatocytes.