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

ABSTRACT

<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>