HIF1A and colorectal cancer: To further confirm the possibility that downregulation of these genes transactivation resulting from miR-1 led to reduction of binding of Smad3 to the promoter sequence, ChIP assays were used to determine whether the binding of Smad3 to HIF-1α, HK2 and MCT4 promoters activated transcription in colorectal cancer cells and confirm the functional importance of miR-1 in recruitment of Smad3.