Bortezomib (LDP 341) is a 20S proteasome inhibitor (Ki=0.6 nM) that is reversible and selective. Bortezomib has antitumor activity and inhibits NF-κB, which can disrupt the cell cycle and induce apoptosis.

20S proteasome:0.6 nM (cell free)

方法：人舌鳞癌细胞 SCC-15 和 CAL-27、人咽鳞癌细胞 FaDu、人唾液腺癌细胞 A-253 和 SALTO-5 用 Bortezomib (6.25-100 nM) 处理 24-72 h，使用 SRB 方法检测细胞生长抑制情况。
结果：Bortezomib 对五种肿瘤细胞增殖的影响是剂量和时间依赖性的。SCC-15 是对 Bortezomib 作用最敏感的细胞。[1]
方法：人小细胞肺癌细胞 NCI-H69 和 NCI-H2171 用 Bortezomib (0.05 μM; 0.5 μM) 处理 48 h，使用 Flow Cytometry 方法检测细胞周期和细胞凋亡情况。
结果：Bortezomib 引起 G2-M 过渡状态下的细胞周期停滞，G2 期细胞增加，S 期细胞减少。Bortezomib 诱导肿瘤细胞凋亡。[2]
方法：人大细胞肺癌细胞 H460 用 Bortezomib (0.01-10 μM) 孵育 3-48 h，使用 Western Blot 方法检测靶点蛋白表达水平。
结果：Bortezomib 处理导致 Bcl-2 蛋白的浓度依赖性磷酸化。从 12 h 开始，观察到可辨别的 Bcl-2 切割产物，Bcl-2 磷酸化先于 Bcl-2 切割至少 9 h。[3]

方法：为检测体内抗肿瘤活性，将 Bortezomib (0.3 mg/kg) 腹腔注射给携带原发性渗出性淋巴瘤 (PEL) UM-PEL-1 的 NOD/SCID 小鼠，每天一次，持续三周。
结果：Bortezomib 诱导 PEL 缓解，并延长淋巴瘤渗出小鼠的总生存期。Bortezomib 下调细胞周期进程、DNA 复制和 Myc 靶基因。[4]
方法：为研究 Bortezomib 对肾纤维化的影响，将 Bortezomib (0.5 mg/kg) 腹腔注射给马兜铃酸I (AA)诱导的纤维化 C57BL/6J 小鼠模型，每周两次，持续十周。
结果：Bortezomib 治疗显著减轻了 AA 诱导的肾功能障碍和蛋白尿，降低了肾纤维化相关蛋白和肾损伤标志物的表达，如 αSMA、Kim1 和 Ngal，并在组织病理学水平上预防了肾纤维化。[5]

Inhibitors were synthesized and purified according to the procedures described in Adams et al.The inhibition constant (Ki) for each inhibitor was measured according to the method of Stein et al.using a fluorometric assay,monitoring peptide substrate cleavage of Z-Leu-Leu-Val-Tyr-amino methyl coumarin (Z = carbobenzyloxy) by the 20S proteasome [1].

PC-3 cells were treated with different doses of PS-341 for different periods of time. The cells were washed with PBS, harvested, and fixed in suspension with 3.7% formaldehyde in the neutral buffer for 10 min at room temperature. The cells were centrifuged, and the cell pellet was resuspended in 0.5 ml of 80% ethanol. The cell suspension (25–50 μl) was then placed onto a microscope slide precoated with poly-l-lysine and air-dried. The slides were washed four times with 0.1% Triton X-100 in PBS. The slide was incubated with the DNA stain Hoechst 33342 (Molecular Probes; 1.0 μg/ml in PBS with 0.1% Triton-X-100) for 1.0 min. The slides were rinsed in PBS and mounted with 70% glycerol containing 25 mg/ml 1,4-diazabicyclo[2.2.2]octane. Nuclear staining was visualized using a fluorescent microscope [1].

Mice were inoculated s.c. into the right flank with 3 × 10^7 MM cells in 100 μl of RPMI 1640, together with 100 μl of Matrigel basement membrane matrix. When tumor was measurable, mice were assigned into four treatment groups receiving PS-341 or into a control group. Treatment with PS-341 was given i.v. twice weekly via tail vein at 0.05, 0.1, 0.5, and 1.0 mg/kg for 4 weeks. Subsequently, it was administered once weekly. The control group received the vehicle alone (0.9% sodium chloride) at the same schedule. Caliper measurements of the longest perpendicular tumor diameters were performed every alternate day to estimate the tumor volume, using the following formula: 4π/3 × (width/2)^2 × (length/2), representing the three-dimensional volume of an ellipse. Animals were sacrificed when their tumors reached 2 cm or when the mice became moribund. Survival was evaluated from the first day of treatment until death [4].