Figure 1.

miR-1278 is downregulated in CRC, and the miR-1278 mimic inhibits tumor growth in vitro and in vivo. (A) The expression of miR-1278 was determined in 42 pairs of CRC samples and the associated peritumoral tissues by qRT-PCR. miR-1278 was downregulated in 34 pairs, while it was upregulated in 8 pairs. (B,C) Relative expression of miR-1278 in CRC tissues compared to the reference gene. ΔCq refers to the Cq of the target gene minus that of the reference gene; thus, –ΔCq represents the miR-1278 expression level normalized to GAPDH. When stratified by T stage, high grade was associated with low expression of miR-1278. When stratified by TNM stage, high grade was correlated with low expression of miR-1278. (D) HT29 and HCT116 cells were transfected with the miR-1278 mimic and verified by qRT-PCR. (E) A colony formation assay was performed to determine the colony formation ability. Transfection of the miR-1278 mimic reduced colony formation in HT29 and HCT116 cells. (F,G) The EdU assay showed that transfection of the miR-1278 mimic significantly inhibited cell proliferation in HT29 and HCT116 cells. (H) Transwell assays showed that transfection of the miR-1278 mimic greatly impaired the migration of HCT116 and SW620 cells. (I) HCT116 cells transfected with miR-1278 or control were subcutaneously injected into nude mice followed by one injection at a 3-day interval. Tumor sizes were measured every 5 days. (J) After ~4 weeks, mice were sacrificed, and tumors were collected. (K) IHC staining of Ki67 demonstrated that Ki67 was downregulated in the miR-1278 mimic group compared to the control group. NC, negative control; Mimic, miR-1278 mimic; **P < 0.01, ***P < 0.001.