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. 2016 Jan 5;6:18824. doi: 10.1038/srep18824

Figure 4. Down-regulation of miR-33b in gastric cancer cells is associated with hypermethylation of miR-33b upstream region.

Figure 4

(A) Schematic illustration of the CpG islands upstream of miR-33b gene within the chr 17p11.2 segment. (B) Effect of 5-Aza-CdR and TSA on miR-33b expression in MGC-803 and HGC-27 gastric cancer cell lines. There is a 1.5-fold increase of miR-33b level after treatment of 5′-AZA (1 μM) also both AZA and TSA, a 1.2-fold increase after treatment of TSA (300 nM) in MGC-803 cells, a 3-fold increase after treatment of 5′-AZA (1 μM), a 2-fold increase after treatment of TSA (300 nM) and 2.5-fold increase after treatment of both AZA and TSA in HGC-27 cells. (C) The analysis of SREBF-1 expression in GC cells treated with AZA and/or TSA. There is an obviously increase of SREBF-1 level after treatment of 5′-AZA (1 μM) (p < 0.01) also both AZA and TSA (p < 0.01), a 8-fold increase after treatment of TSA (300 nM) (p < 0.05) in HGC-27 cells, a 12-fold increase after treatment of 5′-AZA (1 μM) (p < 0.01), a 8-fold increase after treatment of TSA (300 nM) (p < 0.05) and 6-fold increase after treatment of both AZA and TSA (p < 0.05) in MGC-803 cells. All data are shown as mean ± SD. ∗p < 0.05; ∗∗p < 0.01. (D) The methylation level of the CpG island 1 was decreased in GC cells treated with 5′-AZA, suggesting that CpG island 1 was hypermethylated in MGC-803 and HGC-27 cell lines while CpG island 2 and 3 didn’t have obvious changes in these cells. (E) CpG island 1 methylation analysis using qMSP in GC cells. Similar to the results of MSP, the methylation level was decreased in GC cells treated with 5′-AZA. M, methylated state; U, unmethylated state; Methylated control, Methyltransferase treated normal lymphocytes DNA.