PTGS2 and colorectal carcinoma: Lastly, to confirm that the observed phenotypes are indeed due to downregulation of PTGS2 and not to an off-target effect, we performed a rescue experiment by transfecting a PTGS2 expression plasmid into PTGS2-silenced HCT116 and SW480 CRC cells and found that the plasmid reversed sh-PTGS2-mediated inhibition of PTGS2 expression (Supplementary Fig. 1B).