Inhibition of c-MYC-miRNA 19 Pathway Sensitized CML K562 Cells to Etoposide via NHE1 Upregulation

Figure 4

Identification of 3 UTR of NHE1 mRNA as a possible target of miRNAs. (a) K562 cells transfected with pGL3-SLC9A1 showed lower relative luciferase activity than cells transfected with pGL3-control. This result was in according with what was found by introducing another luciferase report assay psiCHECK-2 vector constructed with the same sequence. (b) A schematic diagram of the putative seed regions in the 3 UTR of NHE1. Highly conserved regions among vertebrates were shown in the diagram. By analyzing the sequence of 3 UTR in silico, NHE1 was computationally predicted to be a target of multiple miRNAs, including hsa-miR-19. (c) The mutation of miR-19 binding site could increase activity of 3 UTR, and the same trend was found by using miR-19 inhibitor. (d, e) Activity of SLC9A1 promoter and 3 UTR responded to signaling inhibitors in K562 cells. (f) NHE1 expression at mRNA level was detected in K562 cells with indicated treatments. (g–i) NHE1 expression at protein level was detected in K562 cells with indicated treatments. (j) The pHi value in K562 cells with indicated treatments was detected. Data was shown as of triplicate assays. . . . .

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