Romidepsin (FR 901228) is an HDAC inhibitor that inhibits HDAC1/2/4/6 (IC50=36/47/510/1400 nM). Romidepsin has antitumor activity and can be used for the treatment of peripheral T-cell lymphoma and cutaneous T-cell lymphoma.

HDAC1:36 nM, HDAC2:47 nM

方法：两种恶性 T 细胞系 PEER 和 SUPT1 用 Romidepsin (2.5-40 nM) 处理 48 h，使用 MTT Assay 检测细胞活力。
结果：Romidepsin 抑制 PEER 和 SUPT1细胞活力，IC50 值为 10.8 nM 和 7.9 nM。[1]
方法：CD20+ rituximab 敏感细胞 Raji 细胞和耐药细胞 Raji-2R、Raji-4RH 用 Romidepsin (10 ng/mL) 处理 2 天，使用 Flow Cytometry 检测胞内 caspase 3 激活水平。
结果：Raji 细胞中，Romidepsin 增加了 active caspase 3。在 Raji-2R 和 Raji-4RH 中未检测到 cleaved active caspase 3。[2]

方法：为检测体内抗肿瘤活性，将 Romidepsin (4.4 mg/kg) 腹腔注射给携带人 Burkitt 淋巴瘤 Raji 和 Raji-2R 的 NSG 小鼠，每周一次，持续三周。
结果：Romidepsin 显著抑制异种移植小鼠中 Raji 和 Raji-2R 细胞的生长。[2]
方法：为检测体内抗肿瘤活性，将 Romidepsin (0.03 mg/mouse，0.5% methylcellulose) 腹腔注射给 DEN 诱导肝癌的 C56BL/6 小鼠，每周两次，连续三周。
结果：Romidepsin 抑制肿瘤进展，这种效应与肿瘤细胞增殖减少和凋亡增加有关。[3]

HDAC-inhibitory activity: For the enzyme assay, 10 μL of [3H]acetyl-labeled histones (25,000 cpm/10 μg) are added to 90 μL of the HDAC enzyme fraction extracted from 293T cells overexpressing HDAC1 or HDAC2 in the presence of increasing concentrations of Romidepsin, and the mixture is incubated at 37 °C for 15 minutes. The enzyme reaction is linear for at least 1 hour. The reaction is stopped by the addition of 10 μL of concentrated HCl. The released [3H]acetic acid is extracted with 1 mL of ethylacetate, and 0.9 mL of the solvent layer is taken into 5 mL of aqueous counting scintillant II solution for determination of radioactivity. The IC50 values are determined from at least three independent dose-response curves.

Cells are exposed to various concentrations of Romidepsin for 72 hours in 96-well plates. 20 μL of 5 mg/mL MTT solution in PBS is added to each well for 4 hours. After removal of the medium, 170 μL of DMSO is added to each well to dissolve the formazan crystals. The absorbance at 540 nm is determined. In addition, cells are incubated with trypan blue, and the numbers of blue (dead) cells and transparent (live) cells are counted in a hemocytometer. For cell cycle analysis, cells are incubated for 30 minutes in propidium iodide staining solution containing 0.05 mg/mL propidium iodide, 1 mM EDTA, 0.1% Triton X-100, and 1 mg/mL RNase A in PBS. The suspension is then passed through a nylon mesh filter and analyzed on a Becton Dickinson FACScan. (Only for Reference)