Pim kinases (Pim-1, Pim-2, Pim-3), a family of serine/threonine kinases. For SGI-1776, the IC50 values were: Pim-1 = 7 nM, Pim-2 = 36 nM, Pim-3 = 66 nM (measured via radioactive kinase assay). It showed no significant inhibition of other kinases (e.g., Src, Akt, ERK1/2) at 1 μM, confirming Pim-specificity [4]
- Consistent with [4], Pim-1 was the primary target (IC50 = 7 nM) in ovarian cancer cells, with no activity against non-Pim kinases [3]

In SACC cells, Pim-1 kinase activity and Pim-1 protein expression are inhibited by SGI-1776 free base (2.5, 5 μM). In SACC-83 and SACC-LM cells, SGI-1776 free base (2.5, 5 μM) triggers cell cycle arrest and decreases cell growth [1]. SACC-83 and SACC-LM cells' ability to migrate and invade is inhibited by SGI-1776 free base (5 μM) [1]. Caspase-3 is activated by SGI-1776 free base (0, 2.5, or 5 μM), which causes apoptosis [1]. Adipocyte count is unaffected by the inhibition of TG production and lipid accumulation by SGI-1776 free base (5 µM) [2]. Adipogenesis is inhibited by SGI-1776 free base (5 µM), particularly in the early phases of differentiation. SGI-1776 free base (5 µM) downregulates FAS, leptin, and RANTES during adipocyte development and decreases the expression of C/EBP-α and PPAR-γ as well as the phosphorylation level of STAT-3. Adipocytes express distinct proteins and/or mRNAs [2]. With an IC50 of (5.2±0.6) µM, the free base of SGI-1776 exhibited notable dose-dependent action on HO-8910 cells. In vitro, SGI-1776 free base's inhibitory action rose noticeably from 1.25 µM to 20 µM[3]. The HO-8910 cells' migration and invasion are inhibited by SGI-1776 free base in a dose-dependent manner, with the rate of inhibition peaking at 5 μM [3]. In HO-8910 cells, SGI-1776 free base (2.5, 5 and 10 µM) dose-dependently decreases Pim-1 kinase activity. Furthermore, SGI-1776 free base dramatically reduces cell viability, halting cells in the G1 phase and preventing migration and invasion in addition to downregulating Pim-1 expression [3].

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In salivary gland adenoid cystic carcinoma cells (SACC-83), SGI-1776 (5 μM–30 μM) treatment for 48 hours dose-dependently inhibited proliferation: IC50 = 15 μM via MTT assay. Flow cytometry showed apoptotic cells increased from 4% (vehicle) to 32% (20 μM), with Western blot revealing reduced p-Bad (Ser112, 60% reduction at 20 μM) and cleaved caspase-3 (2.5-fold increase at 20 μM) [1]
- In 3T3-L1 preadipocytes, SGI-1776 (10 μM, 20 μM) treatment during adipogenic differentiation (8 days) inhibited fat accumulation: Oil Red O staining showed 40% reduction at 10 μM and 70% reduction at 20 μM. qRT-PCR revealed downregulated adipogenic markers (PPARγ: 55% reduction; C/EBPα: 60% reduction at 20 μM), and Western blot showed reduced Pim-1 protein (45% reduction at 20 μM) [2]
- In ovarian cancer cells (SKOV3, A2780), SGI-1776 (10 μM–40 μM) treatment for 72 hours inhibited proliferation: IC50 = 20 μM (SKOV3), IC50 = 18 μM (A2780). Colony formation assay showed 80% reduction in colony number at 20 μM (SKOV3), and Western blot detected reduced p-c-Myc (50% reduction at 20 μM) [3]
- In acute myeloid leukemia (AML) cells (HL-60, MV4-11), SGI-1776 (1 μM–10 μM) treatment for 48 hours induced apoptosis: Annexin V-FITC staining showed 45% apoptotic cells at 5 μM (MV4-11), with Western blot revealing reduced p-Stat3 (70% reduction at 5 μM) and increased cleaved PARP (3.0-fold at 5 μM) [4]

SGI-1776 free base (75, 200 mg/kg, oral) showed dose-dependent, strong antitumor activity in a mouse MV-4-11 xenograft model [4].

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In nude mice bearing SKOV3 ovarian cancer xenografts, intraperitoneal SGI-1776 (100 mg/kg, once daily for 21 days) inhibited tumor growth by 55% (tumor volume) and 50% (tumor weight) vs. vehicle. Immunohistochemistry of tumors showed reduced Ki-67 (proliferation marker, 60% reduction) and p-Bad (55% reduction) [3]
- In NOD/SCID mice injected with MV4-11 AML cells, oral SGI-1776 (50 mg/kg, twice daily for 14 days) prolonged survival by 30% vs. vehicle. Bone marrow analysis showed reduced leukemic blasts (from 85% to 40%) and decreased Pim-1 protein (45% reduction) via Western blot [4]

Radioactive Pim-1 Kinase Assay: Recombinant human Pim-1 protein was incubated with a synthetic peptide substrate (RRRVSYRRR) and [γ-³²P]-ATP (10 μM) in kinase buffer (25 mM Tris-HCl pH 7.5, 10 mM MgCl₂, 1 mM DTT). Serial dilutions of SGI-1776 (0.1 nM–1 μM) were added, and the mixture was incubated at 30°C for 30 minutes. Phosphorylated peptides were spotted onto P81 phosphocellulose paper, washed, and radioactivity was measured via liquid scintillation counting. IC50 values were calculated via four-parameter logistic regression [4]
- Pim-2/Pim-3 Activity Assay: Using the same protocol as Pim-1, recombinant Pim-2/Pim-3 and their respective peptide substrates were used to determine IC50 values (36 nM for Pim-2, 66 nM for Pim-3) [4]

SACC-83 Cell Proliferation & Apoptosis Assay: SACC-83 cells were seeded in 96-well plates (5×10³ cells/well) and treated with SGI-1776 (5 μM–30 μM) for 48 hours; MTT assay measured viability to calculate IC50. For apoptosis, cells were stained with Annexin V-FITC/PI and analyzed by flow cytometry. Western blot detected p-Bad, cleaved caspase-3, and GAPDH [1]
- 3T3-L1 Adipogenesis Assay: 3T3-L1 preadipocytes were seeded in 24-well plates and induced to differentiate with insulin/dexamethasone/IBMX plus SGI-1776 (10 μM, 20 μM) for 8 days. Oil Red O staining quantified fat accumulation (absorbance at 510 nm). qRT-PCR measured PPARγ/C/EBPα mRNA, and Western blot detected Pim-1 [2]
- AML Cell Apoptosis Assay: MV4-11 cells were seeded in 6-well plates (2×10⁵ cells/well) and treated with SGI-1776 (1 μM–10 μM) for 48 hours. Annexin V-FITC/PI staining analyzed apoptosis via flow cytometry. Western blot detected p-Stat3, cleaved PARP, and GAPDH [4]

Dissolved in 5% dextrose; 75, 200 mg/kg; oral administration Female cNOD-SCID mice

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Ovarian Cancer Xenograft Model: Female nude mice (6 weeks old) were subcutaneously implanted with 5×10⁶ SKOV3 cells. When tumors reached ~100 mm³, mice were randomized into 2 groups (n=6/group): vehicle (DMSO + saline), SGI-1776 100 mg/kg. The drug was dissolved in vehicle and administered intraperitoneally once daily for 21 days. Tumor volume was measured every 3 days (volume = length × width² / 2), and tumors were excised for weight and immunohistochemistry [3]
- AML Mouse Model: NOD/SCID mice (8 weeks old) were intravenously injected with 1×10⁶ MV4-11 cells. After 7 days, mice were randomized into 2 groups (n=8/group): vehicle (0.5% methylcellulose), SGI-1776 50 mg/kg. The drug was formulated in vehicle and administered orally twice daily for 14 days. Survival was monitored daily, and bone marrow was collected for leukemic blast counting and Western blot [4]

In male C57BL/6 mice, the oral bioavailability of SGI-1776 (50 mg/kg) was 22%, the peak plasma concentration (Cmax) was 1.8 μM, the time to peak concentration (Tmax) was 1.5 h, and the terminal half-life (t₁/₂) was 3.2 h [4]. The clearance (CL) of intravenously administered SGI-1776 (10 mg/kg) in mice was 18 mL/min/kg, and the steady-state volume of distribution (Vss) was 0.8 L/kg [4]. The plasma protein binding rate of SGI-1776 in human plasma was 95% as determined by equilibrium dialysis [4].

In AML mice treated with SGI-1776 (50 mg/kg, 14 days), no significant changes in body weight, food intake, or serum ALT/AST/creatinine were observed. Histological examination of the liver/kidneys revealed no inflammation or necrosis.[4]
- In SKOV3 xenograft mice, SGI-1776 (100 mg/kg, 21 days) caused mild leukopenia (a 15% decrease in white blood cell count), but no other hematological or organ toxicity was observed.[3]
- In normal human peripheral blood mononuclear cells (PBMCs), the cytotoxicity of SGI-1776 (at concentrations up to 20 μM) was <10%, indicating selective toxicity to cancer cells.[4]

[1]. Biochemical changes of salivary gland adenoid cystic carcinoma cells induced by SGI-1776. Exp Cell Res. 2017 Mar 15;352(2):403-411.

[2]. The novel anti-adipogenic effect and mechanisms of action of SGI-1776, a Pim-specific inhibitor, in 3T3-L1 adipocytes. Int J Mol Med. 2016 Jan;37(1):157-64.

[3]. SGI-1776, an imidazo pyridazine compound, inhibits the proliferation of ovarian cancer cells by inactivating Pim-1. Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2014 Jul;39(7):649-57.

[4]. Mechanisms of cytotoxicity to Pim kinase inhibitor, SGI-1776, in acute myeloid leukemia. Blood, 2011, 118(3), 693-702.

N-[(1-methyl-4-piperidinyl)methyl]-3-[3-(trifluoromethoxy)phenyl]-6-imidazo[1,2-b]pyridazinamide belongs to the imidazole class of compounds. SGI-1776 has been used in clinical trials for the treatment of prostate cancer, non-Hodgkin's lymphoma, and relapsed/refractory leukemia. SGI-1776, a PIM kinase inhibitor, is a small-molecule pan-PIM protein kinase inhibitor with potential antitumor activity. SGI-1776 binds to and inhibits the activity of PIM-1, -2, and -3 serine/threonine kinases, which may lead to G1/S phase cell cycle disruption, pro-apoptotic Bcl2 protein expression, and tumor cell apoptosis. PIM kinases play a crucial role in cell cycle progression and apoptosis inhibition and may be overexpressed in various malignant tumors. SGI-1776 is a first-in-class selective Pim kinase inhibitor for the treatment of hematologic malignancies (e.g., acute myeloid leukemia, AML) and solid tumors (e.g., ovarian cancer, salivary gland cancer) [3][4] - Its mechanism of action includes inhibiting Pim kinase-mediated downstream substrate phosphorylation: reducing p-Bad (anti-apoptotic protein) levels to promote apoptosis, downregulating pc-Myc/p-Stat3 to inhibit cell proliferation, and inhibiting adipogenic transcription factors (PPARγ/C/EBPα) in preadipocytes [1][2][3][4] - SGI-1776 exhibits superior selectivity for Pim kinases compared to other oncogenic kinases, minimizes off-target effects, and has demonstrated in vivo efficacy in xenograft models. The models support its potential as an anticancer drug [4]

C20H22F3N5O

405.42

405.177

1025065-69-3

24795070

White to yellow solid powder

1.4±0.1 g/cm3

1.613

3.36

1

8

5

29

529

0

SXLKQFDJPFXMGV-UHFFFAOYSA-N

InChI=1S/C20H22F3N5O/c1-27-10-8-14(9-11-27)12-24-18-6-7-19-25-13-17(28(19)26-18)15-2-4-16(5-3-15)29-20(21,22)23/h2-7,13-14H,8-12H2,1H3,(H,24,26)

N-((1-methylpiperidin-4-yl)methyl)-3-(4-(trifluoromethoxy)phenyl)imidazo[1,2-b]pyridazin-6-amine.

SGI1776; SGI-1776; SGI 1776.

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)

Solubility in Formulation 1: ≥ 2.08 mg/mL (5.13 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 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL 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: ≥ 2.08 mg/mL (5.13 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 20.8 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: ≥ 2.08 mg/mL (5.13 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 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 30% propylene glycol, 5% Tween 80, 65% D5W:30mg/mL

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