Epigenetic silencing of DACH1 induces the invasion and metastasis of gastric cancer by activating TGF-β signalling.
Bottom Line: DACH1 is methylated in 63.3% (62/98) of primary GC and 38% (19/50) of adjacent non-tumour tissues, while no methylation was found in normal gastric mucosa.DACH1 suppresses GC proliferation, invasion and metastasis by inhibiting TGF-β signalling pathways both in vitro and in vivo.Epigenetic silencing DACH1 may induce GC cells' resistance to docetaxel.
Affiliation: Institute of Digestive Diseases, Chinese PLA General Hospital, Beijing, China.Show MeSH
Related in: MedlinePlus
Mentions: To evaluate the effect of DACH1 on GC cell proliferation, colony formation and cell viability were examined. As shown in Figure 5A, the colony number was 678 ± 43 versus 402 ± 57 in BGC823 cells (P < 0.01) and 276 ± 28 versus 167 ± 39 in AGS (P < 0.05) cells before and after restoration of DACH1 expression, showing a 40% reduction in colony formation with restored DACH1 expression. Cell viability was determined by using the CCK-8 kit. The OD value was 1.55 ± 0.24 versus 0.78 ± 0.18 in BGC823 cells (P < 0.01) and 2.08 ± 0.19 versus 1.32 ± 0.17 in AGS cells (P < 0.05) before and after re-expression of DACH1 (Fig. 5B), with a reduction of viability by 37–50% after re-expression of DACH1 in GC cells. These results suggest that DACH1 inhibits GC cell proliferation. To examine the way in which this occurred through cell cycle alterations, flow cytometry technique was employed. The cell phase distribution of DACH1 -unexpressed and -re-expressed BGC823 cells was as follows: 60.22 ± 1.41% versus 48.85 ± 1.37% for G0/1 phase (P < 0.01), 28.17 ± 2.2% versus 23.33 ± 1.2% for S phase (P < 0.05) and 11.6 ± 0.8% versus 27.83 ± 2.05% for G2/M phase (P < 0.01). The cell phase distribution of DACH1 -unexpressed and -re-expressed AGS cells was as follows: 59.03 ± 1.65% versus 47.11 ± 1.12% for G0/1 phase (P < 0.01), 25.66 ± 0.68% versus 23.32 ± 0.33% for S phase (P < 0.05) and 15.31 ± 1.12% versus 29.53 ± 0.85% for G2/M phase (P < 0.01). For both cell lines, G0/1 and S phase were reduced and G2/M phase was increased significantly in BGC823 and AGS cells (Fig. 5C), suggesting induction of a G2/M arrest. To further validate the effect of DACH1 on cell cycle, the expression of cdc2 and cyclinB1, the mitosis initiators, was examined by western blot in BGC823 and AGS cells (Fig. 5D). Both cdc2 and cyclinB1 were decreased after re-expression of DACH1. These results further demonstrated the G2/M phase arrest induced by DACH1 in GC.
Affiliation: Institute of Digestive Diseases, Chinese PLA General Hospital, Beijing, China.