LY2857785 is a potent and selective inhibitor of CDK9 (IC₅₀ = 0.011 μmol/L). It also inhibits CDK8 (IC₅₀ = 0.016 μmol/L) and CDK7 (IC₅₀ = 0.246 μmol/L). It shows good selectivity against a panel of 114 protein kinases, with only 14 kinases inhibited with IC₅₀ < 1 μmol/L.
It is a type I reversible and competitive ATP kinase inhibitor. [1]

For 114 protein kinases, LY2857785 shown good selectivity; only 5 other kinases had inhibitory potencies (IC50) less than 0.1 μM, while 14 kinases had inhibitory effects less than 1 μM. With an IC50 of 0.089 (n=13) and 0.042 (n=1) μM, respectively, LY2857785 inhibits CTD P-Ser2 and CTD P-Ser5 in U2OS cells at the cellular level. But with an EC50 of 0.135 μM, LY2857785 only slightly increased the amount of G2-M DNA, from 35% to 55%. The MV-4-11, RPMI8226, and L363 cells exhibited a strong compound exposure and a time-dependent reduction of cell proliferation when exposed to LY2857785. The cell growth inhibitory potency reached its peak effect after 4 to 24 hours of incubation; for MV-4-11, RPMI8226, and L363 cells, the IC50 values were 0.04, 0.2, and 0.5 μM, respectively. LY2857785 induces a time-dependent apoptosis in cancer cells, with a maximum effectiveness of 8 hours in L363 cells and an IC50 of 0.5 μM [1].

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LY2857785 inhibits RNA polymerase II C-terminal domain (CTD) phosphorylation at Ser2 (IC₅₀ = 0.089 μmol/L) and Ser5 (IC₅₀ = 0.042 μmol/L) in U2OS osteosarcoma cells. [1]
It potently inhibits cell proliferation in a variety of cancer cell lines. In hematologic cancer cells, the maximal inhibitory effect is reached at 8 hours of exposure (e.g., IC₅₀ = 0.04 μmol/L in MV-4-11 cells, 0.2 μmol/L in RPMI8226, and 0.5 μmol/L in L363 cells). In solid tumor cell lines (U2OS, HCT116, A549), IC₅₀ values after 24-hour exposure range from 0.01 to 0.05 μmol/L. [1]
It induces apoptosis in cancer cell lines, as evidenced by caspase-3 activation, TUNEL positivity, PARP cleavage, and reduction of anti-apoptotic proteins MCL1 and XIAP. The induction is time- and concentration-dependent. [1]
In a soft agar colony formation assay using 48 patient-derived solid tumor cell lines, LY2857785 showed a mean IC₅₀ of 0.22 μmol/L, with particular sensitivity in sarcoma, large cell lung cancer, and melanoma models. [1]
In a panel of 24 hematologic tumor cell lines, it showed a geometric mean IC₅₀ of 0.197 μmol/L, with 87% of lines showing intermediate to high sensitivity. Acute myeloid leukemia (AML) cell lines (e.g., MV-4-11, OC1AML2, PL21) were among the most sensitive (IC₅₀ = 0.049–0.072 μmol/L). [1]
In ex vivo studies using peripheral blood mononuclear cells (PBMCs) from AML and chronic lymphocytic leukemia (CLL) patients, LY2857785 potently inhibited CTD P-Ser2 (IC₅₀ = 0.0435 μmol/L in AML and 0.1449 μmol/L in CLL) and induced cell death in a time- and concentration-dependent manner. [1]
It inhibits the proliferation of normal human bone marrow myeloid progenitor cells (CFU-GM assay) in a concentration- and time-dependent manner, with significant inhibition observed after >8 hours of exposure, suggesting potential myelosuppressive toxicity. [1]

LY2857785 demonstrated strong suppression of RNAP II CTD P-Ser2 in HCT116 xenograft tumor mice, with a dose-dependent TED50 of 4.4 mg/kg and a TEC50 of 0.36 μM. Significant CTD P-Ser2 inhibition was also demonstrated by LY2857785 in HCT116 and MV-4-11 nude mouse xenograft models, with durations of 3 to 6 hours at TED70 (8 mg/kg). Additionally, LY2857785 demonstrated dose-dependent inhibition of CTD P-Ser2 at TED70 (7 mg/kg) and TED90 (10 mg/kg) for eight hours in a nude mouse MV-4-11 xenograft model. In the AML MV-4-11 xenograft tumor model, intravenous bolus injection in mice or intravenous infusion in rats showed the greatest tumor regression when LY2857785 was used [1].

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LY2857785 demonstrates dose-dependent inhibition of RNAP II CTD P-Ser2 phosphorylation in xenograft tumor models (HCT116, MV-4-11). The threshold effective dose for 50% inhibition (TED₅₀) was 4.4 mg/kg, with significant inhibition lasting 3–8 hours depending on dose. [1]
It shows potent antitumor efficacy in multiple preclinical models. In an AML MV-4-11 xenograft model in nude mice, intravenous (i.v.) bolus administration (18 mg/kg, TED₉₀) induced tumor regression. In nude rats, 4-hour i.v. infusion also caused dose-dependent tumor regression. [1]
In solid tumor xenograft models (U87MG glioblastoma, A375 melanoma), LY2857785 administered via i.v. bolus or infusion significantly inhibited tumor growth. [1]
In orthotopic murine leukemia models (myr-AKT/Eμ-Myc and Bcl2/Eμ-Myc), LY2857785 administered intravenously or intraperitoneally at various schedules (e.g., 18 mg/kg every 3–7 days) showed dose-dependent inhibition of tumor proliferation and significantly improved animal survival compared to vehicle controls. [1]

Biochemical kinase assays for CDK7, CDK8, and CDK9 were performed. For CDK7 and CDK9 assays, reaction mixtures contained Tris-HCl, HEPES, DTT, ATP, ³³P-ATP, MnCl₂, NaCl, Triton X-100, DMSO, specific peptide substrate, and the respective enzyme complex (CDK7/Mat1/cyclin H or CDK9/cyclin T1). Reactions were incubated at room temperature for 60 minutes and terminated with phosphoric acid or trichloroacetic acid. Product formation was measured by filter binding scintillation counting or ADP detection using fluorescent polarization.
For CDK8/cyclin C assay, reactions were performed in HEPES buffer with DTT, MgCl₂, Triton X-100, ATP, and a specific peptide substrate containing the enzyme. Reactions were similarly quenched and analyzed.
For broad kinase profiling, reactions were conducted in 96-well plates with enzyme, buffer, peptide substrate, diluted compound, and ATP/[³⁵P]. After incubation, reactions were stopped with phosphoric acid, spotted onto filtermats, washed, and counted via scintillation. [1]

For RNAP II CTD phosphorylation inhibition (Acumen assay), U2OS cells were plated in 96-well plates and treated with compounds for 16 hours. Cells were fixed, permeabilized, and incubated with primary antibodies against CTD P-Ser2 or P-Ser5 overnight at 4°C, followed by secondary antibody labeling and propidium iodide staining. Fluorescence was measured using a laser-scanning microplate cytometer.
For cell proliferation and apoptosis assays, solid tumor cells were plated on poly-D-lysine coated plates and hematologic cells on non-coated plates. After compound treatment, cells were fixed and permeabilized. Caspase-3 expression was measured by immunofluorescence, and TUNEL activity was measured using a commercial kit. Both were analyzed via fluorescence microplate cytometer. Hematologic tumor cell viability was also measured using a luminescent cell viability assay.
For the colony formation assay (CFU-GM), normal human bone marrow myeloid progenitor cells were isolated and seeded in methylcellulose-based media with cytokines. Cells were treated with compound for varying durations (4–24 hours). After 10–14 days of incubation, colonies were manually counted, and inhibition was calculated relative to vehicle-treated cells. [1]

For in vivo target inhibition and efficacy studies in xenograft models, human cancer cells (e.g., U87MG, MV-4-11, A375, HCT116) were implanted subcutaneously into female nude rats or mice. When mean tumor volume reached approximately 150–200 mm³, animals were randomized and treated.
LY2857785 was formulated in sterile normal saline (0.9% NaCl) and administered intravenously (i.v.) as a bolus or as a 4-hour or 16-hour infusion at specified doses (e.g., 4, 8, 18 mg/kg) and schedules (e.g., every 3–4 days). Tumor volume was measured and calculated using the formula: volume = length × width² × 0.536.
For orthotopic leukemia models (myr-AKT/Eμ-Myc and Bcl2/Eμ-Myc), transduced mouse embryonic liver cells expressing human oncogenes were transplanted into lethally irradiated C57BL/6 host mice. Leukemic cells from primary animals were passaged into secondary hosts. Mice were inoculated with leukemic cells and treated with LY2857785 (i.v. or i.p.) at various doses and schedules (e.g., 10–20 mg/kg every 1–7 days). Tumor burden and animal survival were monitored. [1]

LY2857785 has high water solubility (>2.0 mg/mL at pH 7.4) and good solution stability, and can be prepared into a 0.9% sodium chloride physiological saline solution at pH 5.5–6. Its logD value (pH 7.4) is 2.11. Its free fraction in human and mouse plasma is 22%. In HCT116 xenograft mice, the effective plasma concentration (TEC₅₀) that inhibits 50% CTD phosphorylation is 0.36 μmol/L. [1]

In vitro experiments showed that LY2857785 inhibited the proliferation of normal human bone marrow myeloid progenitor cells (CFU-GM) in a time- and concentration-dependent manner. Significant inhibition was observed after more than 8 hours of exposure, suggesting possible bone marrow suppression at pharmacologically relevant exposure doses. Its inhibitory efficacy against normal progenitor cells was comparable to its antitumor activity. In vivo experiments showed that high doses of LY2857785 (e.g., 18 mg/kg) were associated with mortality in some xenograft and orthotopic transplantation models (shown as dashed lines on tumor growth curves). No significant weight loss was observed in nude mice, but a maximum weight loss of 9% was observed in the 18 mg/kg group. [1]

[1]. A novel CDK9 inhibitor shows potent antitumor efficacy in preclinical hematologic tumor models. Mol Cancer Ther. 2014 Jun;13(6):1442-56. Mol Cancer Ther. 2014 Jun;13(6):1442-56.

LY2857785 is a novel CDK9 inhibitor discovered through structure-based drug design and medicinal chemistry SAR studies. Its antitumor activity is primarily derived from the inhibition of transcriptional CDKs (especially CDK9), leading to decreased phosphorylation of RNA polymerase II CTD, downregulation of short-lived pro-survival proteins (such as MCL1), and induction of apoptosis. The compound showed preferential activity against hematologic malignancies (especially acute myeloid leukemia and chronic lymphocytic leukemia) in both cell lines and in vitro samples from patients, consistent with the predicted expression profiles of 261 genes. The compound is a substrate of P-glycoprotein (P-gp), as evidenced by the reduced sensitivity observed in P-gp overexpressing cell lines and transport assays. Its in vitro and in vivo properties suggest that, despite its potent activity, its therapeutic window may be limited by myelosuppressive toxicity due to the important role of transcriptional CDKs in normal proliferating cells. [1]

C26H36N6O

448.6036

448.295

1619903-54-6

78357764

White to off-white solid powder

1.3±0.1 g/cm3

671.0±65.0 °C at 760 mmHg

359.6±34.3 °C

0.0±2.1 mmHg at 25°C

1.672

3.71

2

6

6

33

606

0

LHIUZPIDLZYPRL-MXVIHJGJSA-N

InChI=1S/C26H36N6O/c1-17(2)25-22-16-18(4-9-24(22)31-32(25)3)23-10-13-27-26(30-23)29-20-7-5-19(6-8-20)28-21-11-14-33-15-12-21/h4,9-10,13,16-17,19-21,28H,5-8,11-12,14-15H2,1-3H3,(H,27,29,30)/t19-,20-

(1r,4r)-N1-(4-(3-isopropyl-2-methyl-2H-indazol-5-yl)pyrimidin-2-yl)-N4-(tetrahydro-2H-pyran-4-yl)cyclohexane-1,4-diamine

LY2857785; LY-2857785; LY 2857785.

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~10 mg/mL (~22.29 mM)

Solubility in Formulation 1: ≥ 1 mg/mL (2.23 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 10.0 mg/mL clear DMSO stock solution to 400 μL of PEG300 and mix evenly; then add 50 μL of Tween-80 to the above solution and mix evenly; then add 450 μL of normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 1 mg/mL (2.23 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 10.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 1 mg/mL (2.23 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 10.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)