Figure 7.

MLN8237 induces the apoptosis of erythroleukemia cells while minimally affecting the normal hematopoietic cells. (a) MLN8237 (1μM) induced increased apoptosis in HEL, K562, Kasumi-1 and THP1 cells (all P<0.01). (b) MLN8237 (1μM) induced obviously cell apoptosis in erythroleukemia CD34+ cells and other primary leukemia cells (all P<0.01). However, MLN8237 only induced mild cell apoptosis in normal CD34+ hematopoietic. (c) MLN8237 (1 μM) induced significant G2/M phase block and decreased the percentage of cells in S phase in HEL (P=0.007) and K562 (P<0.001). (d) MLN8237 (0.5 μM) obviously inhibited the cell growth of HEL (P<0.001) and K562 cells (P<0.001). (e) MLN8237 (0.5 μM) treatment resulted in apparently increased percentage of senescence cells in HEL (P<0.001) and K562 (P<0.001) cells. (f) GEM analysis was performed in the HEL cells treated with MLN8237 or DMSO to identify some differential genes which are also regulated by MYCN. A total of 120 genes including EZH2 were differentially shared. (g) The representative cross genes are listed. (h) FCM analysis showed that MLN8237 (0.5 μM) repressed the expression of MYCN and EZH2 (all P<0.05). (i) MLN8237 (0.5 μM) treatment diminished the H3K27me3 level while activating the expression of P21 (all P<0.05). (j) WB analysis showed that MLN8237 (0.5 μM) repressed the expression of MYCN, EZH2 and H3K27me3, whereas enhanced the expression of P21. (k) MYCN/EZH2 axis is critical for cell growth, anti-apoptosis, cycle progression, anti-senescence and self-renewal of leukemia cells through repression of p21 expression