OTSSP167 (OTS167) hydrochloride is a highly potent and ATP-competitive MELK inhibitor with IC₅₀ value of 0.41 nM.

IC50: 0.41 nM (MELK)

OTSSP167 inhibits the growth of A549 (lung), T47D (breast), DU4475 (breast), 22Rv1 (prostate) and HT1197 (bladder) cancer cells with IC₅₀ values of 6.7, 4.3, 2.3, 6.0 and 97 nM, respectively^[1]. OTSSP167 can abrogate the mitotic checkpoint, disrupt MCC and MCC-APC/C interaction in MCF7 cells. OTSSP167 causes GFP-MELK localization to cell cortex in prometaphase cells^[2]. OTSSP167 is a MELK selective inhibitor, exhibits a strong in vitro activity, conferring an IC₅₀ of 0.41 nM^[3].

上海金畔生物科技有限公司 has not independently confirmed the accuracy of these methods. They are for reference only.

OTSSP167 (20 mg/kg, i.v.) results in tumor growth inhibition (TGI) of 73% in xenograft mouse model; OTSSP167 (1, 5, and 10 mg/kg, p.o.) reveals TGI of 51, 91, and 108%, respectively. OTSSP167 (20 mg/kg, p.o.) shows no tumor growth suppressive effect on PC-14 xenografts^[1].

上海金畔生物科技有限公司 has not independently confirmed the accuracy of these methods. They are for reference only.

523.88

C₂₅H₂₉Cl₃N₄O₂

1431698-10-0

Room temperature in continental US; may vary elsewhere.

4°C, sealed storage, away from moisture

*In solvent : -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture)

DMSO : 33.33 mg/mL (63.62 mM; Need ultrasonic)

H₂O : 7.14 mg/mL (13.63 mM; Need ultrasonic)

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 (sealed storage, away from moisture)。-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： 10% DMSO    40% PEG300    5% Tween-80    45% saline

  Solubility: ≥ 3 mg/mL (5.73 mM); Clear solution

  此方案可获得 ≥ 3 mg/mL (5.73 mM，饱和度未知) 的澄清溶液。

  以 1 mL 工作液为例，取 100 μL 30.0 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

• 2.

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

  Solubility: ≥ 3 mg/mL (5.73 mM); Clear solution

  此方案可获得 ≥ 3 mg/mL (5.73 mM，饱和度未知) 的澄清溶液。

  以 1 mL 工作液为例，取 100 μL 30.0 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
• 3.

  请依序添加每种溶剂： 10% DMSO    90% corn oil

  Solubility: 3 mg/mL (5.73 mM); Suspended solution; Need ultrasonic

  此方案可获得 3 mg/mL (5.73 mM) 的均匀悬浊液，悬浊液可用于口服和腹腔注射。

  以 1 mL 工作液为例，取 100 μL 30.0 mg/mL 的澄清 DMSO 储备液加到 900 μL玉米油中，混合均匀。

• 4.

  请依序添加每种溶剂： PBS

  Solubility: 1 mg/mL (1.91 mM); Clear solution; Need ultrasonic

• [1]. Chung S, Suzuki H, Miyamoto T, et al. Development of an orally-administrative MELK-targeting inhibitor that suppresses the growth of various types of human cancer. Oncotarget. 2012 Dec 21.

  [2]. Ji W, et al. OTSSP167 Abrogates Mitotic Checkpoint through Inhibiting Multiple Mitotic Kinases. PLoS One. 2016 Apr 15;11(4):e0153518.

  [3]. Cho YS, et al. The crystal structure of MPK38 in complex with OTSSP167, an orally administrative MELK selective inhibitor. Biochem Biophys Res Commun. 2014 Apr 25;447(1):7-11.

  [4]. Jurmeister S, et al. Identification of potential therapeutic targets in prostate cancer through a cross-species approach. EMBO Mol Med. 2018 Feb 5. pii: e8274.

  [5]. Meel MH, et al. MELK inhibition in Diffuse Intrinsic Pontine Glioma. Clin Cancer Res. 2018 Jul 30. pii: clincanres.0924.2018.

For in vitro kinase assay, MELK recombinant protein (0.4 μg) is mixed with 5 μg of each substrate in 20 μL of kinase buffer containing 30 mM Tris-HCl (pH), 10 mM DTT, 40 mM NaF, 10 mM MgCl₂, 0.1 mM EGTA with 50 μM cold-ATP and 10 Ci of [γ-³²P]ATP for 30 min at 30°C. The reaction Is terminated by addition of SDS sample buffer and boiled for 5 min prior to SDS-PAGE. The gel is dried and autoradiographed with intensifying screens at room temperature. OTSSP167 (final concentration of 10 nM) is dissolved in DMSO and added to kinase buffer before the incubation.

上海金畔生物科技有限公司 has not independently confirmed the accuracy of these methods. They are for reference only.

In vitro cell viability is measured by the colorimetric assay using Cell Counting Kit-8. Cells are plated in 100 μL in 96-well plates at a density that generates continual linear growth (A549, 1×10³ cells; T47D, 3×10³ cells; DU4475, 4×10³ cells; 22Rv1, 6×10³ cells; and HT1197, 2×10³ cells, in 100 μL per well). The cells are allowed to adhere overnight before exposure to OTSSP167 for 72 hours at 37°C. Plates are read using a spectrophotometer at a wavelength of 450 nm. All assays are carried out in triplicate.

上海金畔生物科技有限公司 has not independently confirmed the accuracy of these methods. They are for reference only.

MDA-MB-231 cells are injected into the mammary fat pads of NOD.CB17-Prkdc^scid/J mice. A549, MIAPaCa-2 and PC-14 cells (1×10⁵ cells) are injected subcutaneously in the left flank of female BALB/cSLC-nu/nu mice. DU145 cells are injected subcutaneously in the left flank of male BALB/cSLC-nu/nu mice. When MDA-MB-231, A549, DU145, MIAPaCa-2, and PC-14 xenografts has reached an average volume of 100, 210, 110, 250, and 250 mm³, respectively, animals are randomized into groups of 6 mice (except for PC-14, for which groups of 3 mice are used). For oral administration, OTSSP167 and other compounds are prepared in a vehicle of 0.5% methylcellulose and given by oral garbage at the indicated dose and schedule. For intravenous administration, compounds are formulated in 5% glucose and injected into the tail vein. An administration volume of 10 mL per kg of body weight is used for both administration routes. Tumor volumes are determined every other day using a caliper.

上海金畔生物科技有限公司 has not independently confirmed the accuracy of these methods. They are for reference only.

• [1]. Chung S, Suzuki H, Miyamoto T, et al. Development of an orally-administrative MELK-targeting inhibitor that suppresses the growth of various types of human cancer. Oncotarget. 2012 Dec 21.

  [2]. Ji W, et al. OTSSP167 Abrogates Mitotic Checkpoint through Inhibiting Multiple Mitotic Kinases. PLoS One. 2016 Apr 15;11(4):e0153518.

  [3]. Cho YS, et al. The crystal structure of MPK38 in complex with OTSSP167, an orally administrative MELK selective inhibitor. Biochem Biophys Res Commun. 2014 Apr 25;447(1):7-11.

  [4]. Jurmeister S, et al. Identification of potential therapeutic targets in prostate cancer through a cross-species approach. EMBO Mol Med. 2018 Feb 5. pii: e8274.

  [5]. Meel MH, et al. MELK inhibition in Diffuse Intrinsic Pontine Glioma. Clin Cancer Res. 2018 Jul 30. pii: clincanres.0924.2018.