Description |
Temsirolimus is an inhibitor of mTOR with an IC50 of 1.76 μM.
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Target |
mTOR:1.76 μM (IC50)
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In Vitro |
Temsirolimus potently inhibits mTOR kinase activity with IC50 of 1.76 μM, similar to that of rapamycin with IC50 of 1.74 μM in the absence of FKBP12. Temsirolimus (10 nM to <5 μM) displays a modest and selective antiproliferative activity via FKBP12-dependent mechanism, but can completely inhibit the proliferation of a broad panel of tumor cells at low micromolar concentrations (5-15 μM), involving FKBP12-independent suppression of mTOR signaling. Temsirolimus treatment at micromolar but not nanomolar concentrations (20 μM) causes a marked decline in global protein synthesis and disassembly of polyribosomes, accompanied by rapid increase in the phosphorylation of translation elongation factor eEF2 and the translation initiation factor eIF2A[1]. Temsirolimus inhibits the phosphorylation of ribosomal protein S6, more potently in PTEN-positive DU145 cells than in PTEN-negative PC-3 cells, and inhibits cell growth and clonogenic survival of both cells in a concentration-dependent manner[2]. Temsirolimus (100 ng/mL) potently inhibits proliferation and induces apoptosis in primary human lymphoblastic leukemia (ALL) cells[3].
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In Vivo |
CCI-779 (20 mg/kg, i.p.) inhibits the growth of both prostate cancer xenografts, and the rowth of PC-3 tumors is inhibited in a dose-dependent manner and growth inhibition is greater than for DU145 tumors[2]. In the NOD/SCID xenograft models with human ALL, Temsirolimus treatment at 10 mg/kg/day produces a decrease in peripheral blood blasts and in splenomegaly[3]. Administration of Temsirolimus (20 mg/kg, i.p. 5 days/week) significantly delays the growth of DAOY xenografts by 160% after 1 week and 240% after 2 weeks, compared with controls. Single high-dose of Temsirolimus (100 mg/kg, i.p) treatment induces 37% regression of tumor volume within 1 week. Temsirolimus treatment for 2 weeks also delays the growth of rapamycin-resistant U251 xenografts by 148%[4]. Inhibition of mTOR by Temsirolimus improves performance on four different behavioral tasks and decreases aggregate formation in a mouse model of Huntington disease[5]. Administration of Temsirolimus induces significant dose-dependent, antitumor responses against subcutaneous growth of 8226, OPM-2, and U266 xenografts with ED50 of 20 mg/kg and 2 mg/kg for 8226 and OPM-2, respectively, which are associated with inhibited proliferation and angiogenesis, induction of apoptosis, and reduction in tumor cell size[6].
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Cell Assay |
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.
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Animal Admin |
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.
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Density | 1.2±0.1 g/cm3 |
Boiling Point | 1048.4±75.0 °C at 760 mmHg |
Flash Point | 587.8±37.1 °C |
Exact Mass | 1029.602539 |
PSA | 241.96000 |
LogP | 2.96 |
Vapour Pressure | 0.0±0.6 mmHg at 25°C |
Storage condition | -20°C Freezer |