Abstract
EGR1 regulates the expression of its downstream target genes and may exert different biological effects in different tumours. We found that the expression of EGR1 was increased in gastric cancer (GC), and silencing the expression of EGR1 promoted the apoptosis of GC cells. Moreover, overexpression of EGR1 repressed the apoptosis of GC cells. Bioinformatics analysis showed that EGR1 had binding sites at the upstream promoter region of miR-195; ChIP assays were applied to determine EGR1 occupancy of the miR-195 promoter. The RT-PCR results showed that EGR1 suppressed the expression of miR-195. The mechanism by which EGR1 acts as a transcriptional repressor is still unclear. Bioinformatics analysis showed that EGR1 may interact with DNMT3L. We confirmed that EGR1 and DNMT3L formed a complex, and EGR1 was an important player in the transcriptional control of miR-195. Overexpression of miR-195 inhibited proliferation and promoted apoptosis in GC cells. We found a well-matched miR-195 binding site at the AKT3 3'-UTR. Double luciferase reporter assays showed that AKT3 was a target of miR-195, and silencing AKT3 repressed cell proliferation and promoted apoptosis. Our results indicated EGR1 may interact with DNMT3L to inhibit the miR-195-AKT3 axis and regulate the GC cell apoptosis.