Entinostat is an oral and selective class I HDAC inhibitor, with IC₅₀s of 243 nM, 453 nM, and 248 nM for HDAC1, HDAC2, and HDAC3, respectively.

Binding affinity of Entinostat (MS-275) against HDAC1 and HDAC2 is 282 nM and 156 nM, respectively^[1]. Effects of the HDAC inhibitor Entinostat (MS-275) have been examined in human leukemia and lymphoma cells (U937, HL-60, K562, and Jurkat) as well as in primary acute myelogenous leukemia blasts in relation to differentiation and apoptosis. MS-275 displays dose-dependent effects in each of the cell lines. When administered at a low concentration (e.g., 1 μM), MS-275 exhibits potent antiproliferative activity, inducing p21CIP1/WAF1-mediated growth arrest and expression of differentiation markers (CD11b) in U937 cells. Entinostat (MS-275) potently induces cell death, triggering apoptosis in ~70% of cells at 48 h^[2].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Entinostat (MS-27-275) at 49 mg/kg shows marked antitumor effects against KB-3-1, 4-1St, and St-4 tumor lines, and a moderate effect against Capan-1 tumor. Entinostat at 24.5 mg/kg and 12.3 mg/kg also shows significant effects against these tumors. In addition, oral administration of Entinostat apparently increases the level of histone acetylation in HT-29 tumor xenografts 4-24 h after the administration^[3]. MS-275 administration (3.5 mg/kg i.p.) to Experimental autoimmune neuritis (EAN) rats once daily from the appearance of first neurological signs greatly reduces the severity and duration of EAN and attenuated local accumulation of macrophages, T cells and B cells, anddemyelination of sciatic nerves. In addition, MS-275 treatment increases proportion of infiltrated Foxp3⁺ cells and anti-inflammatory M2 macrophages in sciatic nerves of EAN rats^[4].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

376.41

C₂₁H₂₀N₄O₃

209783-80-2

恩替诺特

Room temperature in continental US; may vary elsewhere.

DMSO : 50 mg/mL (132.83 mM; ultrasonic and warming and heat to 60°C)

请根据产品在不同溶剂中的溶解度选择合适的溶剂配制储备液；一旦配成溶液，请分装保存，避免反复冻融造成的产品失效。
储备液的保存方式和期限：-80°C, 6 months; -20°C, 1 month。-80°C 储存时，请在 6 个月内使用，-20°C 储存时，请在 1 个月内使用。

请根据您的实验动物和给药方式选择适当的溶解方案。以下溶解方案都请先按照 In Vitro 方式配制澄清的储备液，再依次添加助溶剂：

——为保证实验结果的可靠性，澄清的储备液可以根据储存条件，适当保存；体内实验的工作液，建议您现用现配，当天使用； 以下溶剂前显示的百
分比是指该溶剂在您配制终溶液中的体积占比；如在配制过程中出现沉淀、析出现象，可以通过加热和/或超声的方式助溶

• 1.

  请依序添加每种溶剂： 5% DMSO    40% PEG300    5% Tween-80    50% saline

  Solubility: ≥ 2.5 mg/mL (6.64 mM); Clear solution
• 2.

  请依序添加每种溶剂： 10% DMSO    40% PEG300    5% Tween-80    45% saline

  Solubility: ≥ 2.08 mg/mL (5.53 mM); Clear solution

  此方案可获得 ≥ 2.08 mg/mL (5.53 mM，饱和度未知) 的澄清溶液。

  以 1 mL 工作液为例，取 100 μL 20.8 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀；向上述体系中加入50 μL Tween-80，混合均匀；然后继续加入 450 μL生理盐水定容至 1 mL。

  将 0.9 g 氯化钠，完全溶解于 100 mL ddH₂O 中，得到澄清透明的生理盐水溶液

• 3.

  请依序添加每种溶剂： 10% DMSO    90% (20% SBE-β-CD in saline)

  Solubility: ≥ 2.08 mg/mL (5.53 mM); Clear solution

  此方案可获得 ≥ 2.08 mg/mL (5.53 mM，饱和度未知) 的澄清溶液。

  以 1 mL 工作液为例，取 100 μL 20.8 mg/mL 的澄清 DMSO 储备液加到 900 μL 20% 的 SBE-β-CD 生理盐水水溶液中，混合均匀。

  将 2 g 磺丁基醚 β-环糊精加入 5 mL 生理盐水中，再用生理盐水定容至 10 mL，完全溶解，澄清透明
• 4.

  请依序添加每种溶剂： 10% DMSO    90% corn oil

  Solubility: ≥ 2.08 mg/mL (5.53 mM); Clear solution

  此方案可获得 ≥ 2.08 mg/mL (5.53 mM，饱和度未知) 的澄清溶液，此方案不适用于实验周期在半个月以上的实验。

  以 1 mL 工作液为例，取 100 μL 20.8 mg/mL 的澄清 DMSO 储备液加到 900 μL玉米油中，混合均匀。

• [1]. Lauffer BE, et al. Histone deacetylase (HDAC) inhibitor kinetic rate constants correlate with cellular histone acetylation but not transcription and cell viability. J Biol Chem. 2013 Sep 13;288(37):26926-43.

  [2]. Rosato RR, et al. The histone deacetylase inhibitor MS-275 promotes differentiation or apoptosis in human leukemia cells through a process regulated by generation of reactive oxygen species and induction of p21CIP1/WAF1 1. Cancer Res. 2003 Jul 1;63(13):36

  [3]. Saito A, et al. A synthetic inhibitor of histone deacetylase, MS-27-275, with marked in vivo antitumor activity against human tumors. Proc Natl Acad Sci U S A, 1999, 96(8), 4592-4597.

  [4]. Zhang ZY, et al. MS-275, an histone deacetylase inhibitor, reduces the inflammatory reaction in rat experimental autoimmune neuritis. Neurosci, 2010, 169, 370-377.

Biochemical assays of HDAC activity are carried out by Nanosyn in a reaction volume of 10 μL in 384-well microplates. A standard enzymatic reaction contains 5 μL of 2× HDAC inhibitor (e.g., Entinostat), 4 μL of 2.5× enzyme, and 1 μL of 10× substrate in assay buffer (100 mM HEPES, pH 7.5, 25 mM KCl, 0.1% BSA, 0.01% Triton X-100, 1% DMSO). Final concentration of all HDACs in the enzymatic assays is between 0.5 and 5 nM. A final substrate concentration of 1 μM FAM-RHKK(Ac)-NH₂ or FAM-RHKK(trifluoroacetyl)-NH₂ is used in all assays and found to be below the determined K_m,app for each enzyme^[1].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

SH-SY5Y cells are maintained under normal culture conditions in a humidified incubator at 37°C with 5% CO₂ and are split twice weekly. Cells are plated in black 384-well plates at 2500 cells/well in 20-μL volume of DMEM/F-12 culture media supplemented with 10% FBS and permitted to adhere overnight. The following day, HDAC inhibitors (e.g., Entinostat) are serially diluted in 100% DMSO, and this series is subsequently cross-diluted into culture media. 5 μL of compound (e.g., Entinostat) diluted in media is added to the appropriate well of the cell plate to afford the indicated final concentration of inhibitor (e.g., Entinostat) with a final 0.1% DMSO. Treated cells are incubated under normal tissue culture conditions for 6, 24, 48, 72, or 96 h prior to quantitation of cellular ATP levels as measured using CellTiter-Glo reagents. Similarly, after 6 h of incubation with HDAC inhibitors (e.g., Entinostat), media from separate cell plates are aspirated, and cells are washed once with media containing no inhibitors. 25 μL of media supplemented with 10% FBS and 0.1% DMSO (no inhibitors) is added back to the cells, and cellular ATP levels are determined using CellTiter-Glo after 24, 48, 72, or 96 h of incubation. Luminescence is measured at each time point using an Envision Instrument with a 0.1 s count time^[1].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Mice^[3]
A2780 cells (9×10⁶) are suspended in PBS and are injected subcutaneously into the flank of nude mouse. For the other tumor lines, KB-3-1, HCT-15, 4-1St, Calu-3, St-4, Capan-1, and HT-29, tumors are passaged several times before starting in vivo antitumor testing, and a tumor lump (2-3 mm in diameter) is transplanted subcutaneously into the flank of a nude mouse by using a trocar needle. Treatment (four or five mice in each experimental group) with the drugs is started after the tumors are confirmed to have grown in the body (tumor size, 20-100 mm³). Entinostat is administered orally once daily 5 days per week for 4 weeks. Tumor length and width are monitored twice weekly, and tumor volume is calculated.
Rats^[4]
Male Lewis rats (8-10 weeks, 170-200 g) are housed under a 12-h light/dark cycle with free access to food and water. For therapeutic treatment, EAN rats receive i.p. injection of MS-275 (3.5 mg/kg) daily from day 10 to day 14 (six rats/group). For injection, MS-275 is suspended in phosphate buffered saline (PBS) and the same volume (1 mL) of PBS is given to control rats.

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

• [1]. Lauffer BE, et al. Histone deacetylase (HDAC) inhibitor kinetic rate constants correlate with cellular histone acetylation but not transcription and cell viability. J Biol Chem. 2013 Sep 13;288(37):26926-43.

  [2]. Rosato RR, et al. The histone deacetylase inhibitor MS-275 promotes differentiation or apoptosis in human leukemia cells through a process regulated by generation of reactive oxygen species and induction of p21CIP1/WAF1 1. Cancer Res. 2003 Jul 1;63(13):36

  [3]. Saito A, et al. A synthetic inhibitor of histone deacetylase, MS-27-275, with marked in vivo antitumor activity against human tumors. Proc Natl Acad Sci U S A, 1999, 96(8), 4592-4597.

  [4]. Zhang ZY, et al. MS-275, an histone deacetylase inhibitor, reduces the inflammatory reaction in rat experimental autoimmune neuritis. Neurosci, 2010, 169, 370-377.