JQ1 reduces the cell viability of MM cells, modulates c-MYC and p21 expression, and induces apoptosis. (A) JQ1 decreases MM cell viability. A panel of MM cell lines was treated with the indicated concentrations of JQ1 for 72 hours. Cell viability was measured by MTT assay. (B) Quantitative RT-PCR (qRT-PCR) analysis of c-MYC and CDKN1A levels. MM cells were treated with 500 nM JQ1 for 24 hours, and gene expression was measured by qRT-PCR. (C) JQ1 treatment decreases c-MYC protein expression and induces p21. RPMI-8226, LP-1, and OPM-2 MM cells were treated with the indicated concentrations of JQ1 for 24 hours (left) or 500 nM JQ1 (right) for the indicated times. Protein expression was determined by immunoblotting. (D) JQ1 stimulates apoptosis in MM cell lines. LP-1 and OPM-2 MM cells were treated with the indicated concentrations of JQ1 for 48 hours. Apoptosis was determined by propidium iodide fluorescence-activated cell sorting (PI-FACS) analysis. Data are shown as mean ± standard deviation (SD); n = 3. *Indicates a significant difference from controls. P < .05.