Effect of 3F plasmid in combination with Pax4 overexpression on the expression of genes associated with the differentiation of human umbilical cord mesenchymal stem cells to pancreatic β-like cells. The genes assessed included NKX6-1, SLC2A2, GCK, PCSK1, NEUROD1, ISL1, PAX6 and PCSK2. Values are expressed as the mean ± standard deviation (n=5). *P<0.05, **P<0.01, ***P<0.001 vs. EGFP group; #P<0.05, ##P<0.01 vs. 3F group. Groups: EGFP, cells transfected with EGFP plasmid; 3F, cells transfected with Pdx1/MafA/Ngn3 plasmid; Pax4, cells transfected with Pax4 plasmid; 3F/Pax4, cells transfected with Pdx1/MafA/Ngn3 plasmid and Pax4 plasmid. Pdx1, pancreatic and duodenal homeobox 1; MafA, MAF bZIP transcription factor A; Ngn3, neurogenin 3; Pax4, paired box 4; EGFP, enhanced green fluorescence plasmid; GCK, glucokinase; NKx6.1, NK6 homeobox 1; SLC2A2, glucokinase; PCSK1, proprotein convertase subtilisin/kexin type 1; NEUROD1, neuronal differentiation 1; ISL1, ISL LIM homeobox 1; PCSK2, proprotein convertase subtilisin/kexin type 2.