THZ1 Hydrochloride 

For kinase assays following immunoprecipitation of FLAG-CDK7 protein from HCT116 or FLAG-CDK12 from 293A cellular lysates, cells are first treated with THZ1, THZ1-R, or DMSO for 4 hrs at 37°C. Cells are then harvested by lysis in 50 mM Tris HCl pH 8.0, 150 mM NaCl, 1% NP-40, 5 mM EDTA, and protease/phosphatase cocktails. Exogenous CDK7 or CDK12 proteins are immunoprecipitated from cellular lysates using FLAG antibody- conjugated agarose beads. Precipitated proteins are washed with lysis buffer 6 times, followed by 2 washes with kinase buffer (40 mM Hepes pH 7.5, 150 mM NaCl, 10 mM MgCl₂, 5% glycerol) and subjected to in vitro kinase assays at 30°C for 45 minutes using 1 μg of the large subunit of RNAPII (RPB1) as substrate and 25 μM ATP and 10 μCi of 32P ATP. Note: no additional inhibitors are added to the kinase reaction mixture, therefore any inhibition results from the activity of the compounds that are added directly to cells (ie-intracellular inhibition). This suggests that the inhibitors are either covalently tethered to the kinase or have strong non-covalent character. Kinase assays using recombinant CDK7/TFIIH/MAT1 are conducted in the manner as described above using 25 ng of CAK complex per reaction. For kinase assays designed to test time-dependent inactivation of CDK7 kinase activity, CAK complex is pre-incubated with indicated concentrations of THZ1, THZ1-R, or DMSO in kinase buffer without ATP for 4 hrs at 30°C prior to being subjected to kinase assay conditions^[1].

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

Jurkat, Loucy, KOPTK1, and DND-41 cell lines are seeded in 384-well microplates at 15% confluency in medium with 5% FBS and penicillin/streptavidin. Cells are treated with THZ1 (2, 10, 50, 250, 1250, and 6250 nM) or DMSO for 72 hrs and cell viability is determined using resazurin^[1].

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

Mice^[1]
Thirty-two NOD-SCIDIL2Rcγnull (NSG) 9-week old female mice are divided into treatment groups based on mean BLI as follows: THZ1 10 mg/kg qD, THZ1 10 mg/kg BID, and vehicle (10% DMSO in D5W) BID (n=10 for all groups). Two mice are excluded, one with the highest and one with the lowest BLI. All treatments are administered via IV injection in the lateral tail vein in a volume of 3.3 μL/g (non-blinded). Mice are imaged and weighed every 3-5 days. Mice are treated for four weeks and on the final day mice are imaged, dosed and sacrificed approximately 5-6 hrs post dose. Upon sacrifice, blood is collected via cardiac puncture in EDTA tubes; a portion (300 uL) is processed for plasma. Liver and spleen tissues are collected from each mouse with half of each sample flash frozen and half of each sample fixed. Blood plasma and liver samples are processed for pharmacokinetics analysis of THZ1. Spleen tissues are homogenized and lysed and processed for pharmacodynamics analysis of THZ1 target engagement.

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

• [1]. Kwiatkowski N, et al. Targeting transcription regulation in cancer with a covalent CDK7 inhibitor. Nature. 2014 Jul 31;511(7511):616-20.  [Content Brief]

  [2]. Jiang YY, et al. Targeting super-enhancer-associated oncogenes in oesophageal squamous cell carcinoma. Gut. 2016 May 10. pii: gutjnl-2016-311818.  [Content Brief]

  [3]. Christensen CL, et al. Targeting transcriptional addictions in small cell lung cancer with a covalent CDK7 inhibitor. Cancer Cell. 2014 Dec 8;26(6):909-22.  [Content Brief]

  [4]. Chipumuro, et al. CDK7 inhibition suppresses super-enhancer-linked oncogenic transcription in MYCN-driven cancer. Cell. 2014 Nov 20;159(5):1126-39. ?  [Content Brief]