Temsirolimus  (Synonyms: CCI-779)

The Flag-tagged wild-type human mTOR (Flag-mTOR) DNA constructs are transiently transfected into HEK293 cells. Protein extraction and purification of Flag-mTOR are carried out 48 hours later. In vitro kinase assays of purified Flag-mTOR in the presence of various concentrations of Temsirolimus without FKBP12 are performed in 96-well plate and detected by dissociation-enhanced lanthanide fluorescent immunoassay (DELFIA) using His6-S6K1 as the substrate. Enzymes is first diluted in kinase assay buffer (10 mM Hepes (pH 7.4), 50 mM NaCl, 50 mM β-glycerophosphate, 10 mM MnCl₂, 0.5 mM DTT, 0.25 μM microcystin LR, and 100 μg/mL BSA). To each well, 12 μL of the diluted enzyme is mixed briefly with 0.5 μL Temsirolimus. The kinase reaction is initiated by adding 12.5 μL kinase assay buffer containing ATP and His6-S6K to give a final reaction volume of 25 μL containing 800 ng/mL FLAG-mTOR, 100 μM ATP, and 1.25 μM His6-S6K. The reaction plate is incubated for 2 hours (linear at 1-6 hours) at room temperature with gentle shaking and then terminated by adding 25 μL Stop buffer (20 mM Hepes (pH 7.4), 20 mM EDTA, and 20 mM EGTA). The DELFIA detection of the phosphorylated (Thr-389) His6-S6K is performed at room temperature using a monoclonal anti-P(T389)-p70S6K antibody labeled with Europium-N1-ITC (Eu) (10.4 Eu per antibody). 45 μL of the terminated kinase reaction mixture is transferred to a MaxiSorp plate containing 55 μL PBS. The His6-S6K is allowed to attach for 2 hours after which the wells are aspirated and washed once with PBS. 100 μL of DELFIA buffer with 40 ng/mL Eu-P(T389)-S6K antibody is added. The antibody binding is continued for 1 hour with gentle agitation. The wells are then aspirated and washed four times with PBS containing 0.05% Tween 20 (PBST). 100 μL of DELFIA Enhancement solution is added to each well and the plates are read in a PerkinElmer Victor model plate reader.

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

Survival of prostate cancer cells following various treatments is also determined in a colony-forming assay. Exponentially growing cells are exposed to varying doses of mitoxantrone or docetaxel for 24 hours, or to CCI-779 for 3 days. Following this treatment, the cells are washed and trypsinized. Serial dilutions are plated in 6-well plates in 5 mL medium. The plates are incubated for 10 days at 37°C in an atmosphere containing 5% CO₂ at 90% humidity. The plates are then stained with methylene blue and colonies containing >50 cells are counted.

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

For generation of xenografts, cells are implanted in matrigel; matrigel is stored at −20°C and then thawed on ice at 4°C for 3 hours before use. Cells are gently resuspended in 1 mL of PBS and incubated on ice for 5 minutes. A prechilled pipette is used to transfer cells to the tube containing 1 mL of matrigel, and the cell concentration is adjusted to 3×10⁷/mL. The cells (3×10⁶ in 0.1 mL) are injected s.c. into both flanks of mice using a 25-gauge needle. When xenografts grew to a size of about 5 mm in diameter, animals are assorted randomLy into groups of 10 mice. The following experiments are conducted: Mice bearing PC-3 tumors are treated with CCI-779 (1, 5, 10, and 20 mg per kg per day), or vehicle solution for 3 or 5 days per week for 3 weeks. Mice bearing DU145 tumors are only treated with CCI-779 (20 mg per kg per day) or vehicle solution for 3 weeks. Mice bearing PC-3 tumors receive the following treatments: (a) control, vehicle solution for CCI-779; (b) chemotherapy alone, mitoxantrone 1.5 mg/kg or docetaxel 10 mg/kg is injected i.p. weekly for 3 doses; (c) CCI-779 alone, 5 or 10 mg/kg is injected i.p. daily, three times a week for 3 weeks; (4) chemotherapy followed by CCI-779.

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

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  [2]. Wu L, et al. Effects of the mammalian target of rapamycin inhibitor CCI-779 used alone or with chemotherapy on human prostate cancer cells and xenografts. Cancer Res, 2005, 65(7), 2825-2831.  [Content Brief]

  [3]. Teachey DT, et al. The mTOR inhibitor CCI-779 induces apoptosis and inhibits growth in preclinical models of primary adult human ALL. Blood, 2006, 107(3), 1149-1155.  [Content Brief]

  [4]. Geoerger B, et al. Antitumor activity of the rapamycin analog CCI-779 in human primitive neuroectodermal tumor/medulloblastoma models as single agent and in combination chemotherapy. Cancer Res, 2001, 61(4), 1527-1532.  [Content Brief]

  [5]. Ravikumar B, et al. Inhibition of mTOR induces autophagy and reduces toxicity of polyglutamine expansions in fly and mouse models of Huntington disease. Nat Genet. 2004 Jun;36(6):585-95. Epub 2004 May 16.  [Content Brief]

  [6]. Frost P, et al. In vivo antitumor effects of the mTOR inhibitor CCI-779 against human multiple myeloma cells in a xenograft model. Blood. 2004 Dec 15;104(13):4181-7. Epub 2004 Aug 10.  [Content Brief]

  [7]. Dela Cruz FS, et al. A case study of an integrative genomic and experimental therapeutic approach for rare tumors: identification of vulnerabilities in a pediatric poorly differentiated carcinoma. Genome Med. 2016 Oct 31;8(1):116.  [Content Brief]

  [8]. Jason C. Choi, et al. Temsirolimus activates autophagy and ameliorates cardiomyopathy caused by lamin A/C gene mutation. Sci Transl Med. 2012 Jul 25; 4(144): 144ra102.  [Content Brief]