Growth Inhibition of Multiple Myeloma Cells Caused by MicroRNA-15a and Its Mechanisms / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore the effect and possible mechanisms of miR-15a on growth of multiple myeloma(MM) cells.</p><p><b>METHODS</b>MM cell lines (U266 and RPMI8226) were transfected by lentiviral particles. MM stable cell lines were selected and collected by flow cytometry (FCM). Proliferation of MM cells before and after miR-15a high expression was detected by CCK-8 method. Apoptosis of MM cells before and after miR-15a high expression was detected by AO/EB dying, Hoechst 33258 dying and FCM, respectively. Cell cycle of MM cells before and after miR-15a high expression was detected by FCM. The expressions of miR-15a, BMI-1 and BCL-2 mRNA of MM cells before and after miR-15a high expression were detected by real-time PCR. The expressions of BMI-1 protein of MM cells before and after miR-15a high expression were detected by Western blot.</p><p><b>RESULTS</b>MM stable cell lines with miR-15a high expression was acquired. CCK-8 result showed that high expression of miR-15a could inhibit growth of MM cells (U266 and RPMI8226). AO/EB dying, Hoechst 33258 dying and FCM testing results showed that high expression of miR-15a could significantly induce apoptosis of MM cells (U266 and RPMI8226). The apoptosis rates of U266 and RPMI8226 cells in high expression group and control group were 90.52% vs 37.08% and 59.40% vs 44.17%, respectively. Meanwhile, FCM testing results showed that high expression of miR-15a could induce G1 arrest of MM cells (U266 and RPMI8226), which proportion of G1 phase were 41.50%±0.64%, 45.31%±0.77%, respectively. Real-time PCR results showed that during the growth inhibition process of MM cells caused by miR-15a high expression, the expression of BCL-2 mRNA decreased, but there was no significant changes in the expression of BMI-1 mRNA, while the expression of BMI-1 protein decreased significantly.</p><p><b>CONCLUSION</b>High expression of miR-15a can induce cell cycle arrest and apoptosis of MM cells, then inhibit their growth. The mechanisms may be related with the negative regulation of BMI-1 and BCL-2 genes in post-transcription level caused by miR-15a.</p>

Expression and Clinical Significance of Bmi-1 and P14 in Extranodal NK/T-cell Lymphoma / 中国实验血液学杂志

<p><b>OBJECTIVE</b>This study was aimed to investigate the expression and clinical significance of Bmi-1 and P14 in extranodal NK/T-cell lymphoma (ENKTCL) tissue.</p><p><b>METHODS</b>Maxvision immunohistochemistry technique was used to detect the expression level of Bmi-1 and P14 in the tissues of 21 patients with ENKTCL and 11 normal lymph nodes. The correlation of Bmi-1 or P14 expression with the clinical features and the correlation between Bmi-1 and P14 expression were analyzed.</p><p><b>RESULTS</b>The expression of Bmi-1 protein was higher in tissues of ENKTCL than that in tissues of lymph nodes, and the Bmi-1 expression levels did not correlate with patients' sex, age, lactate dehydrogenase (LDH), International Prognostic Index (IPI) scores and B symptoms (P > 0.05), except for clinical stage (P < 0.05). The P14 protein expression level was lower in ENKTCL tissues than in normal lymph node tissues, which did not correlate with age, sex, LDH, IPI scores, clinical stage and B symptoms. Correlation test showed a negative correlation between Bmi-1 and P14 (r = -0.472, P = 0.031).</p><p><b>CONCLUSION</b>Bmi-1 protein over-expresses in ENKTCL tissues that may display a negative-regulation effect on P14 in the genesis and progress of ENKTCL.</p>

Anti-leukemia mechanism of miR-17 and miR-20a silencing mediated by miRNA sponge / 中国实验血液学杂志

This study was aimed to quantitatively detect the expression levels of pre-miR-17 and pre-miR-20a in acute leukemia patients and eight kinds of leukemia cell lines, and to investigate the anti-leukemia mechanism of miR-17 and miR-20a silence mediated by miRNA Sponge. Quantitative real-time PCR was used to detect the mRNA expression levels of pre-miR-17 and pre-miR-20a in patients with various types of leukemia and leukemia cell lines. The Jurkat cells over-expressing miR-17 and miR-20a were transfected with recombinant lentivirus-transfecting units targeted at miR-17 and miR-20a plus 6 µg/ml of polybrene. Then the proliferation ability and cell cycle of Jurkat cells was evaluated by CCK-8 and flow cytometry respectively. The results showed that the expression level of pre-miR-17 and pre-miR-20a in all leukemia patients was significantly higher than that in normal group(P < 0.05), the expression of pre-miR-17 and pre-miR-20a in acute lymphoid leukemia was significantly higher than that in acute myeloid leukemia(P < 0.05), and the pre-miR-17 and pre-miR-20a expression level did not correlate significantly with high white blood cell count>20.0×10(9)/L(P > 0.05). The miR-17 and miR-20a silencing mediated by miRNA Sponge led to a significant decrease of cell growth, restored G1 accumulation and increase of cell apoptosis. It is concluded that the expression of miR-17 and miR-20a is upregulated in leukemia patients, which may contribute to leukemogenesis. Over-expressed miR-17 and miR-20a promote cell growth and cell cycle progression, and inhibit apoptosis through negatively-regulating P21 and E2F1 after-transcriptionally.