CBP/β-catenin interaction

PRI-724 treatment reduced mRNA expression of β-catenin target genes in SL4-inoculated livers.[1]
PRI-724 treatment reduced mRNA expression of β-catenin target genes in SL4-inoculated livers.[1]
PRI-724 increased T-lymphocyte infiltration into metastatic liver tumors.[1]
CD8+ T-cells were required for the anti-tumor effect of combined anti-PD-L1 Ab and PRI-724 treatment.[1]

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PRI-724 exhibits antitumor activity in the mouse xenograft models of colon cancer. The initial results of the Phase I clinic trial of PRI-724 has been disclosed publically. The drug exhibits an acceptable toxicity profile with only one dose-limiting toxicity of grade 3 reversible hyperbilirubinaemia. An Open-Label dose-escalation phase I/II study of PRI-724 for patients with advanced myeloid malignancies is still ongoing.

Measurement of serum cytokines and chemokines [1]
Serum ALT levels were measured using a Wako Transaminase CII-test Kit. Serum cytokines and chemokines were measured using a Luminex MILLIPLEX MAP Mouse Cytokine/Chemokine Magnetic Bead Panel - Immunology Multiplex Assay. This procedure was performed in accordance with the manufacturer’s instructions.

Isolation of mouse IHLs [1]
Single-cell suspensions were prepared from the liver median lobe by digesting the tissue in RPMI-1640 containing 0.02% collagenase IV and 0.002% DNase I for 40 min at 37°C. The cells were overlaid onto Lympholyte-M in PBS. After density separation, the isolated IHLs were evaluated by FACS analysis.

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FACS analysis [1]
The cells were surface-stained with fluorochrome-conjugated Abs for 20 min on ice using the following Abs: anti-CD3, anti-CD4, anti-CD8, anti-NK1.1, anti-CD69, and anti-Foxp3. To perform intracellular cytokine staining, IHLs were co-cultured with SL4 cells (1 × 105 cells/well) for 4 h at 37°C in 96-well round-bottom plates containing 200 μL/well RPMI-1640 medium. Mouse recombinant IL-2 (50 units) and 0.2 μL of BD GolgiPlug protein transport inhibitor were added to each well. After incubation, the cells were harvested, washed in PBS containing 1% FBS, and incubated for 10 min on ice with unlabeled anti-mouse CD16/32 Ab to block FcγRII/III binding. The cells were then surface-stained for 20 min on ice with the indicated Abs. Following staining, the cells were washed to remove unbound Ab and fixed using a Cytofix/Cytoperm Kit. Cells were then subjected to secondary staining with reagents obtained from BioLegend except as noted, including the following: FITC-conjugated CD107a, PE-conjugated anti-interferon gamma, and anti-IL-10.

Liver metastasis model [1]
Male wild-type C57BL/6J mice 8-weeks of age were obtained from Japan SLC. After making a small incision under anesthesia to expose the spleen, 0.1 mL of a viable cell suspension containing 5 × 106 cells/mL was injected into the spleen. We chose SL4 cells because the cells grow rapidly, even in the liver of wild-type mice. The animals were then each intraperitoneally injected with or without 0.4 mg PRI-724 and/or 200 μg of an anti-PD-L1 Ab (10F.9G2) three times per week. In addition, some mice treated with PRI-724 and the anti-PD-L1 Ab were administrated anti-mouse CD4 or CD8 Ab (250 μg/mouse) three times per week. After the course of treatment, the mice were anesthetized and humanely sacrificed by exsanguination 14 days post cell-inoculation. The livers of the animals were immediately removed, washed in ice-cold PBS, and weighed before a portion of the dissected liver tissue was frozen in liquid nitrogen. Additional animals were maintained and used for survival analysis.

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Dissolved in PBS; 300 mg/kg; i.p. administration

C57BL/6 and Balb/c mice

[1]. Oncotarget.2019Apr 30;10(32):3013-3026;
[2]. Transl Respir Med.2014 Sep 11;2:8;
[3]. Am J Cancer Res.2015 Jul 15;5(8):2344-60.

PRI-724 is under investigation in clinical trial NCT03620474 (Safety and Effectiveness of PRI-724 for Hepatitis C or B Virus Derived Liver Cirrhosis).
Foscenvivint is a potent, specific inhibitor of the canonical Wnt signaling pathway in cancer stem cells with potential antineoplastic activity. Foscenvivint specifically inhibits the recruiting of beta-catenin with its coactivator CBP (the binding protein of the cAMP response element-binding protein CREB); together with other transcription factors beta-catenin/CBP binds to WRE (Wnt-responsive element) and activates transcription of a wide range of target genes of Wnt/beta-catenin signaling. Blocking the interaction of CBP and beta-catenin by this agent prevents gene expression of many proteins necessary for growth, thereby potentially suppressing cancer cell growth. The Wnt/beta-catenin signaling pathway regulates cell morphology, motility, and proliferation; aberrant regulation of this pathway leads to neoplastic proliferation.

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Emami and colleagues have identified the small molecule PRI-724 (also named as ICG-001) that down-regulates the Wnt/β-catenin signaling by specifically binding to CBP. PRI-724 was shown to selectively induce apoptosis in colon carcinoma cells but not in normal colon cells, and exhibit antitumor activity in the mouse xenograft models of colon cancer. Interestingly, PRI-724 binds specifically to the co-activator CBP, but not to the closely related homologue p300.[3]

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Immune checkpoint blockade with specific antibodies can accelerate anti-tumor immunity, resulting in clinical responses in patients with various types of cancer. However, these antibodies achieve only partial tumor regression. Thus, a wide variety of treatment combinations based on programmed death-ligand 1 (PD-L1) pathway inhibition are under development to enhance such therapeutic effects. In this study, the effects of combination treatment using PRI-724, a selective inhibitor of CBP/β-catenin, and an anti-PD-L1 antibody were examined in a mouse model of colon cancer liver metastasis. Mice were inoculated with SL4 colon cancer cells to produce metastatic liver tumors. The combination treatment resulted in regression of tumor growth, whereas monotherapy with each treatment individually failed to exhibit any anti-tumor activity. In addition, co-administration of the inhibitor and antibody induced CD8+CD44lowCD62Llow cells and interferon (IFN)-γ production in CD8+ T-cells in the liver compared with that in control mice. Administration of an anti-CD8 antibody mitigated the anti-tumor effects of the combined treatment of PRI-724 and anti-PD-L1 antibody. In conclusion, targeting CBP/β-catenin, combined with PD-1/PD-L1 immune checkpoint blockade, shows potential as a new therapeutic strategy for treating liver metastasis during colon cancer.[1]

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Background: Wnt/β-catenin signaling has been suggested to regulate proximal-distal determination of embryonic lung epithelium based upon genetically modified mouse models. The previously identified and characterized small molecule inhibitor IQ1 can pharmacologically decrease the interaction between β-catenin and its transcriptional coactivator p300, thereby enhancing the β-catenin/CBP interaction. Inhibition of the β-catenin/p300 interaction by IQ1 blocks the differentiation of embryonic stem cells and epicardial progenitor cells; however, whether differential coactivator usage by β-catenin plays a role in proximal-distal determination of lung epithelium is unknown. Methods: We examined the effects of inhibiting the β-catenin/p300 interaction with IQ1 on lung branching morphogenesis in mouse embryos in utero and mouse embryonic lung organ culture ex vivo. The phenotype of IQ1 treated lungs was analyzed by epithelial staining, histology, quantitative PCR and in situ hybridization. Results: Inhibition of the β-catenin/p300 interaction by IQ1 disrupted the distal branching of mouse lung epithelium both in utero and ex vivo. IQ1 proximalized lung epithelium with decreased expression of the genes Bmp4 and Fgf10, hallmarks of distal lung determination, and increased expression of the proximal genes Sox2 and Scgb1a1 (CC10) as shown by quantitative PCR and in situ hybridization. The disruption of branching was reversible ex vivo as branching was reinitiated after removal of IQ1 from the media. Conclusions: The results demonstrate that the β-catenin/p300 interaction plays a critical role in proximal-distal determination of the epithelium in mouse lung branching morphogenesis and β-catenin/p300 inhibition pharmacologically proximalizes lung epithelium.[2]

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As described previously, small molecule PRI-724 can block interaction of CBP with β-catenin for Wnt signaling inhibition. The initial results of the Phase I clinic trial of PRI-724 has been disclosed publically. Overall, PRI-724 was given to 18 patients as a continuous infusion for 7 days, and the drug exhibited an acceptable toxicity profile with only one dose-limiting toxicity of grade 3 reversible hyperbilirubinaemia. An Open-Label dose-escalation phase I/II study of PRI-724 for patients with advanced myeloid malignancies is still ongoing. Additionally, clinical trials of combination of PRI-724 with other therapeutic agents are underway. For instance, a Phase I trial was initiated to treat patient with colorectal cancer by administering PRI-724 in combination with a modified regimen of FOLFOX6 (mFOLFOX 6). Furthermore, a current Phase I trial is testing continuous intravenous doses of PRI-724, in combination with Gemcitabine, to treat patients with advanced or metastatic pancreatic adenocarcinoma.[3]

C33H35N6O7P

658.6408

658.23

C, 60.18; H, 5.36; N, 12.76; O, 17.00; P, 4.70

1422253-38-0

1422253-38-0 (PRI-724);1198780-38-9 847591-62-2 (deleted);780757-88-2 (ICG001);

71509318

Solid powder

0.3

3

9

8

47

1170

3

P(=O)(O)(O)OC1C=CC(=CC=1)C[C@H]1C(N(CC2=CC=CC3C=CC=NC2=3)[C@@H](C)[C@]2([H])N(C(NCC3C=CC=CC=3)=O)N(C)CC(N21)=O)=O

VHOZWHQPEJGPCC-AZXNYEMZSA-N

InChI=1S/C33H35N6O7P/c1-22-31-38(29(40)21-36(2)39(31)33(42)35-19-24-8-4-3-5-9-24)28(18-23-13-15-27(16-14-23)46-47(43,44)45)32(41)37(22)20-26-11-6-10-25-12-7-17-34-30(25)26/h3-17,22,28,31H,18-21H2,1-2H3,(H,35,42)(H2,43,44,45)/t22-,28-,31-/m0/s1

(6S,9aS)-N-benzyl-6-(4-hydroxybenzyl)-8-(naphthalen-1-ylmethyl)-4,7-dioxooctahydro-1H-pyrazino[1,2-a]pyrimidine-1-carboxamide

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)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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