NKD1 and colonic neoplasm: The pcDNA3.1 plasmid, pcDNA3.1-PPARδ plasmid, pcDNA3.1-PPARδ + negative control siRNA (NC siRNA), and pcDNA3.1-PPARδ + NKD1 siRNA were consecutively transfected into colon cancer HCT116 and SW480 cells.