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Objective To investigate the effect of interleukin( IL)-6 secreted by bone marrow stromal cells HS-5 on activity and apoptosis of human acute myeloid leukemia( AML) cells HL-60 and its possible mechanism. Methods HL-60 cells and HS-5 cells were cultured in vitro, and the co-culture system was established. Scanning electron microscope, ELISA, cell counting kit-8( CCK-8) , AnnexinV-FITC/PI, double-staining flow cytometry, Real-time PCR and Western blotting techniques were used to detect the changes of viability and apoptosis of HL-60 cells, respectively. HL-60 cells from different groups were inoculated into BALB/c nude mice to observe and record tumorigenesis. Results IL-6 secreted by bone marrow stromal cells HS-5 could enhance the viability and inhibit the apoptosis of HL-60 cells, and down-regulate the expression of pro-apoptotic gene Bax and and up-regulate the expression of anti-apoptotic gene Bcl-2 in HL-60 cells. HL-60 cells in co-culture group had the strongest tumorigenicity in BALB/c nude mice, while HL-60 cells alone had the weakest tumorigenicity. Conclusion Part of the mechanism by which bone marrow stromal cells HS-5 promote the proliferation of HL-60 cells and inhibit their apoptosis may be through the secretion of IL-6.
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Objective@#To investigate the effects of miR-23a-3p on proliferation, migration and apoptosis on human acute myeloid leukemia (AML) cells by targeting SMC1A.@*Methods@#Microarray analysis was used to screen differentially expressed microRNAs and mRNAs in human AML cells. Real-time fluorescence quantitative PCR (RT-qRCR) was used to detect the expressions of miR-23a-3p and SMCA in human AML cell line U937. TargetScan database was used to analyze the correlation between miR-23a-3p and SMC1A. Double luciferase reporter gene was used to detect the interaction between miR-23a-3p and SMC1A. The effect of miR-23a-3p expression on the proliferation of U937 cells was detected by clonal assay. The migration, apoptosis, cell cycle and caspase-3 activity of U937 cells regulated by miR-23a-3p were detected by cell scratch assay and flow cytometry, respectively. Western blot was used to detect the expressions of Bax and Bcl-2 in U937 cells.@*Results@#Compared with human normal monocyte SC group (1.00), the expression of miR-23a-3p in U937 cells was up-regulated (2.56±0.78) (P<0.01), while the expression of SMC1A was down-regulated (0.48±0.56, P<0.01). miR-23a-3p specifically bond to SMC1A 3′UTR and regulated the expression activity of SMC1A. Overexpression of miR-23a-3p promoted the proliferation and migration of U937 cells and inhibited the apoptosis of U937 cells, while up-regulation of SMC1A inhibited the proliferation and migration of U937 cells and promoted the apoptosis of U937 cells. The percentages of G0/G1 phase, G2/M phase and S phase cells in the negative control group were (37.48±0.21)%, (16.78±0.18)% and (45.74±0.15)% respectively, and those in the miR-23a-3p mimics group were (19.96±0.11)%, (41.69±0.24)% and (38.24±0.34)%, respectively. The difference was statistically significant (all P<0.05). The proportions of G0/G1 phase, G2/M phase and S phase cells in the group of miR-23a-3p mimics+ pcDNA3.1-SMC1A were (36.88±0.21)%, (30.44±0.33)% and (32.88±0.16)%, respectively, without significant difference when compared with those of the miR-23a-3p mimics group (P>0.05). The relative expression levels of Bax and Bcl-2 protein in the negative control group were 0.55±0.45 and 0.31±0.54, respectively. Overexpression of miR-23a-3p inhibited the expression of Bax protein in U937 cells (0.23±0.13, P<0.001), promoted the expression of Bcl-2 protein (0.50±0.23, P<0.01), while SMC1A increased the expression of Bax protein in U937 cells (0.40±0.11, P<0.01), and inhibited the expression of Bcl-2 protein (0.37±0.15). In the negative control group, caspase-3 activity was (25.82±0.89)%. Overexpression of miR-23a-3p inhibited caspase-3 activity in U937 cells (3.64±0.56)%, P<0.01, while up-regulation of SMC1A promoted caspase-3 activity in U937 cells (15.29±0.85)%, P<0.01.@*Conclusion@#miR-23a-3p can inhibit the proliferation and migration and promote apoptosis of human AML cells by targeting SMC1A.