[Expression of Blimp1、ATF4 and CHOP in Multiple Myeloma Cells and Effect of Aspirin on Their Expression]

To explore the expression of Blimp1, ATF4 and CHOP in bone marrow mononuclear cells from patients with multiple myeloma as well as the effect of aspirin on their expression.

Sixty untreated patients with multiple myeloma and 30 patients with relatively normal bone marrow were selected. Mononuclear cells from the bone marrow fluid were separated using Ficoll separation solution. CD138⁺ plasma cells were sorted by immunomagnetic beads method. RT-PCR was used to detect the expression levels of Blimp1, ATF4 and CHOP mRNA in U266 cells cultured in vitro. The cells were divided into blank control group, negative control group (no-loaded virus transfection) and positive experimental group [LV-Blimp1-RNAi (40051-2) transfection] by lentivirus transfection. RT-PCR was used to detect the expression of Blimp1, ATF4 and CHOP mRNA in cells of different groups. U266 cells were stimulated in vitro with different concentrations of aspirin solution (0, 0.5 mmol/L, 2.5 mmol/L, 5.0 mmol/L) for 24, 48 h and 72 h, respectively. The ability of cell proliferation in different groups was measured by CCK-8. U266 cells were stimulated with different concentrations of aspirin for 48 hours. And the mRNA expression of Blimp1, ATF4 and CHOP was detected by RT-PCR.

Compared with plasma cells in normal group, the expression of Blimp1 mRNA in CD138⁺ plasma cells of MM patients significantly increased (8.040±1.878), and the mRNA expression levels of ATF4 and CHOP significantly decreased (0.735±0.089; 0.837±0.062) (P＜0.05). U266 cells were cultured in vitro. Compared with the blank control group and the negative control group, the mRNA expression level of Blimp in the positive experimental group was significantly down-regulated after infection with LV-Blimp1-RNAi (40051-2) lentiviral expression vector (0.637±0.021). ATF4 and CHOP mRNA expression levels were significantly increased (1.452 ± 0.027; 1.721 ± 0.038) (P＜0.05). The proliferation of U266 cells decreased after stimulation with aspirin. In the range of (0.5-5) mmol/L, aspirin could significantly inhibit the proliferation of U266 cells. The inhibition effect of aspirin was increased along with prolongation of time and increase of concentrations. After aspirin stimulation of different concentrations for 48 hours, the expression level of Blimp1 in U266 cells decreased with increasing of drug concentration, while the expression levels of ATF4 and CHOP increased with increasing of drug concentration.

Inhibition of Blimp1 expression in multiple myeloma cells can promote the expression of ATF4 and CHOP. Aspirin can inhibit the proliferation activity of myeloma cells by down-regulating Blimp1 expression in myeloma cells and up-regulating ATF4 and CHOP expression, therefore plays an anti-tumor rote.