[Bortezomib Inhibits Extranodal Natural Killer/T Cell Lymphoma, Nasal Type by Targeting NF-κB Signaling Pathway]

Objective: To investigate the anti-tumor effect of bortezomib on extranodal natural killer/T cell lymphoma, nasal type (ENKTL).

Methods: SNK-6 cells were treated with different mass concentrations of bortezomib (0, 1, 2, 4, 5, 6 ng/mL) for 24, 48, 72 h, and different concentrations of nuclear factor-kappa B (NF-κB) signaling pathway inhibitor BAY11-7082 (0, 1, 2, 2.5, 5, 10, 20 μmol/L) for 24 h respectively, then the cell viability was measured by CCK8 kit and the half inhibitory concentration (IC ₅₀) was calculated. SNK-6 cells were treated with 30μmol/L Z-VAD-FMK (Pan-caspase inhibitor)+3ng/mL bortezomib, and 5, 10 μmol/L BAY11-7082+3 ng/mL bortezomib for 24 h respectively, then the cell viability was measured by CCK8 kit. After treatment of SNK-6 cells with different mass concentrations of bortezomib for 24 h, apoptosis was detected by AnnexinⅤ/PI flow cytometry; the expression of apoptosis-related protein Caspase-3, poly ADP-ribose polymerase (PARP) and Bcl-2 and NF-κB signaling pathway key proteins P65 and P100/P52 were detected by Western blot.

Results: Bortezomib inhibited the proliferation of SNK-6 cells in a dose-dependent manner ( P<0.05), and IC ₅₀( (2.87±0.06) ng/mL) at 24 h was lower than that at 48 h and 72 h ( P<0.05). BAY11-7082 also inhibited the proliferation of SNK-6 cells with an IC ₅₀= (9.73±0.36) μmol/L at 24 h. The combination treatment indicated that Z-VAD-FMK could attenuate the inhibitory effect of bortezomib on the proliferation of SNK-6 cells ( P<0.05), while BAY11-7082 could enhance the inhibitory effect of bortezomib on the proliferation of SNK-6 cells ( P<0.05). After treatment of SNK-6 cells with bortezomib for 24 h, apoptosis-related protein Caspase-3 cleavage, PARP activation, and Bcl-2 cleavage; NF-κB signaling pathway-related protein P65 phosphorylation level decreased, and P52 decreased.

Conclusion: Bortezomib inhibits ENKTL cells proliferation by inhibiting NF-κB signaling pathway and induces apoptosis of ENKTL cells via mitochondria-mediated caspase pathway.