Fig. 4

PGE2 regulates its own degradation by regulating miR-21 and its target gene HPGD. UM1 cells were treated with either control siRNA or specific siRNAs against COX2 (a), or treated with either COX2 inhibitor CelecoxiB or vehicle (b), or treated with either PGE2 or vehicle (c), or treated with either control siRNA or specific siRNAs against HPGD (d). The relative level of miR-21 was assessed by qRT-PCR. e UM1 cells were treated with PGE2, CelecoxiB or vehicle, and the cell proliferation was assessed by MTT assay. Data represent at least 3 independent experiments with similar results. *: p < 0.05. f Potential role of the positive feed-forward loop among PGE2, miR-21 and PHGD in OTSCC