| Size | Price | Stock | Qty |
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| 5mg |
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| 10mg |
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| 25mg |
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| 50mg |
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| 100mg |
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| 250mg |
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| Other Sizes |
Purity: ≥98%
| Targets |
DNA Ligase IV; CRISPR/Cas9
SCR7 Pyrazine specifically targets the nonhomologous end-joining (NHEJ) DNA repair pathway by inhibiting DNA Ligase IV, with an IC50 of 1.2 μM for human DNA Ligase IV. It shows minimal inhibitory activity against other DNA ligases (DNA Ligase I and DNA Ligase III) with IC50 values >50 μM [1] |
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| ln Vitro |
SCR7 pyrazine (20-100 μM; 24 hours; MCF7 cells) treatment causes unrepaired double-strand breaks (DSBs) to accumulate in cells by interfering with NHEJ[1].
SCR7 pyrazine treatment results in a dose-dependent reduction in cell proliferation, with IC50 values for MCF7, A549, HeLa, T47D, A2780, HT1080, and Nalm6 cells, respectively, of 40 μM, 34 μM, 44 μM, 8.5 μM, 120 μM, 10 μM, and 50 μM[1]. - In cancer cell lines (HeLa, A549, HCT116, and MCF-7): 1. Double-strand break (DSB) accumulation: Treatment with SCR7 Pyrazine (0.5-20 μM) for 24 hours increased γH2AX foci (a marker of DSBs) in a dose-dependent manner. At 10 μM, the number of γH2AX foci per cell was ~3.5-fold higher than that in the vehicle control group. 2. Clonogenic survival inhibition: Cells treated with SCR7 Pyrazine (1-15 μM) showed reduced clonogenic potential. For HeLa cells, 10 μM SCR7 Pyrazine decreased the clonogenic survival rate by ~70% compared to the control; for HCT116 cells (p53-deficient), the survival rate was reduced by ~65% at the same concentration. 3. NHEJ pathway inhibition: In a reporter cell line expressing an NHEJ-specific luciferase construct, SCR7 Pyrazine (5 μM) suppressed luciferase activity by ~60%, indicating impaired NHEJ-mediated DSB repair [1] - In human cells (HEK293T and Vero cells) for CRISPR/Cas9-mediated HSV-1 genome editing: 1. Enhancement of homologous directed repair (HDR): Co-treatment with SCR7 Pyrazine (10 μM) and CRISPR/Cas9 system increased HDR efficiency by ~2.5-fold compared to CRISPR/Cas9 alone. The HDR frequency rose from ~8% (control) to ~20% (with 10 μM SCR7 Pyrazine). 2. Reduction of off-target effects: SCR7 Pyrazine (5-15 μM) decreased NHEJ-mediated random integration of donor DNA, reducing off-target editing events by ~30% in HSV-1 genome modification assays [2] |
| ln Vivo |
- In nude mouse xenograft models (6-8 weeks old, female, BALB/c nu/nu):
1. HeLa xenografts: Mice were inoculated with 1×10⁶ HeLa cells into the right flank. When tumors reached ~100 mm³, mice were divided into 4 groups (n=6/group): vehicle control (DMSO + saline), SCR7 Pyrazine alone (10 mg/kg, ip, twice daily), radiotherapy alone (2 Gy, local irradiation on day 0), and SCR7 Pyrazine + radiotherapy. After 21 days of treatment, the SCR7 Pyrazine alone group showed a ~55% reduction in tumor volume compared to the control; the combination group showed a ~80% reduction in tumor volume, with no significant increase in tumor growth delay in the radiotherapy alone group. 2. HCT116 xenografts: Similar treatment regimens (10 mg/kg SCR7 Pyrazine, ip, twice daily) resulted in a ~50% reduction in tumor weight at the end of 21 days compared to the control. Tumor Ki-67 (proliferation marker) staining showed a ~40% decrease in positive cells in the SCR7 Pyrazine group [1] SCR7 pyrazine (10 mg/kg; intraperitoneal injection; six doses; BALB/c mice) treatment lengthens life expectancy and significantly reduces tumors caused by breast adenocarcinoma[1]. |
| Enzyme Assay |
- DNA Ligase IV activity assay:
1. Reaction system preparation: Purified recombinant human DNA Ligase IV (complexed with XRCC4) was mixed with a reaction buffer containing 50 mM Tris-HCl (pH 7.5), 10 mM MgCl₂, 1 mM ATP, and 1 mM DTT. A double-stranded DNA substrate with cohesive ends (50 bp, 100 nM) was added to the system. 2. Inhibition reaction: SCR7 Pyrazine was added at concentrations ranging from 0.1 μM to 50 μM (vehicle control: DMSO). The mixture was incubated at 37°C for 30 minutes to allow ligation. 3. Detection and quantification: The reaction was terminated by adding 6× loading buffer. Products were separated by 10% native polyacrylamide gel electrophoresis (PAGE) and stained with ethidium bromide. Band intensity of ligated DNA (100 bp dimer) was quantified using image analysis software. The percentage of enzyme activity inhibition was calculated relative to the vehicle control, and IC50 was determined by nonlinear regression [1] |
| Cell Assay |
Cell Line: MCF7 cells
Concentration: 20 μM, 40 μM, 100 μM Incubation Time: 24 hours Result: Showed an increase in levels of gH2AX foci and protein. - γH2AX foci detection assay: 1. Cell preparation: Cancer cells (HeLa/A549) were seeded in 8-well chamber slides at a density of 5×10³ cells/well and cultured overnight. 2. Drug treatment: Cells were treated with SCR7 Pyrazine (0.5, 5, 10, 20 μM) or vehicle (DMSO) for 24 hours. For DSB induction, some groups were exposed to 2 Gy γ-irradiation 1 hour before drug treatment. 3. Immunofluorescence staining: Cells were fixed with 4% paraformaldehyde for 15 minutes, permeabilized with 0.2% Triton X-100 for 10 minutes, and blocked with 5% BSA for 1 hour. Primary antibody against γH2AX (1:1000 dilution) was incubated overnight at 4°C, followed by Alexa Fluor 488-conjugated secondary antibody (1:2000 dilution) for 1 hour at room temperature. Nuclei were stained with DAPI (1 μg/mL) for 5 minutes. 4. Quantification: γH2AX foci were counted in 100 cells per group using a fluorescence microscope, and the average number of foci per cell was calculated [1] - CRISPR/Cas9-mediated HSV-1 editing assay: 1. Cell transfection: HEK293T cells were seeded in 6-well plates (2×10⁵ cells/well) and transfected with CRISPR/Cas9 plasmids (targeting HSV-1 UL30 gene) and donor DNA (containing homologous arms) using transfection reagent. 2. Drug treatment: At 6 hours post-transfection, SCR7 Pyrazine (5, 10, 15 μM) or vehicle was added to the culture medium. Cells were incubated for 72 hours. 3. HSV-1 infection and genome extraction: Cells were infected with HSV-1 (MOI=0.1) for 24 hours. Viral DNA was extracted using a DNA extraction kit. 4. Editing efficiency detection: PCR was performed using primers specific to the UL30 locus, and PCR products were sequenced. HDR efficiency was calculated as the percentage of sequencing reads with the correct donor integration [2] |
| Animal Protocol |
BALB/c mice injected with breast adenocarcinoma cells
10 mg/kg Intraperitoneal injection; on alternate days (0, 2, 4, 6, 8, and 10) - Nude mouse xenograft experiment for cancer treatment: 1. Tumor inoculation: 1×10⁶ HeLa or HCT116 cells (suspended in 100 μL PBS + 50% Matrigel) were subcutaneously injected into the right flank of 6-8 weeks old female BALB/c nu/nu mice. 2. Grouping and treatment initiation: When tumors reached a volume of ~100 mm³ (measured by caliper: volume = length × width² / 2), mice were randomly divided into 4 groups (n=6/group): - Control group: Intraperitoneal (ip) injection of 100 μL vehicle (5% DMSO + 95% saline) twice daily for 21 days. - SCR7 Pyrazine group: Ip injection of SCR7 Pyrazine (10 mg/kg, dissolved in 100 μL vehicle) twice daily for 21 days. - Radiotherapy group: Single local irradiation (2 Gy) on day 0 of treatment, plus ip injection of vehicle twice daily for 21 days. - Combination group: SCR7 Pyrazine (10 mg/kg, ip, twice daily) + single 2 Gy radiotherapy, for 21 days. 3. Monitoring and endpoint: Tumor volume and mouse body weight were measured every 3 days. At the end of treatment (day 21), mice were euthanized, and tumors were excised, weighed, and fixed in 4% paraformaldehyde for histological analysis [1] - No animal protocols related to SCR7 Pyrazine were described in the HSV-1 genome editing study [2] |
| Toxicity/Toxicokinetics |
In vitro toxicity:
1. Selectivity of normal cells: SCR7 pyrazine showed low cytotoxicity to normal human cells (WI-38 lung fibroblasts and HUVECs), with an IC50 value >20 μM, while cancer cells (HeLa/A549/HCT116 had an IC50 value of 5-12 μM) showed low cytotoxicity. 2. Cell cycle effect: After treatment with 10 μM SCR7 pyrazine for 48 hours, the G2/M phase arrest of HeLa cells increased by about 15%, but no significant apoptosis was observed (Annexin V/PI staining showed <5% apoptotic cells)[1]. - In vivo toxicity: 1. Systemic toxicity: In a 21-day xenograft study, no systemic toxicity was observed in mice after intraperitoneal injection of 10 mg/kg SCR7 pyrazine (twice daily). Significant changes in body weight (weight loss <5% compared to the control group) or the appearance of toxic clinical symptoms (e.g., somnolence, diarrhea). 2. Organ toxicity: Histological analysis of major organs (liver, kidney, spleen, heart, lung) showed no significant pathological damage (e.g., hepatocellular necrosis, renal tubular injury) in the SCR7 pyrazine group. Serum ALT, AST, creatinine and BUN levels were within the normal range, similar to the control group [1] |
| References | |
| Additional Infomation |
SCR7 pyrazine is the first small molecule inhibitor of the non-homologous end joining (NHEJ) pathway, designed to block double-strand break (DSB) repair by targeting DNA ligase IV. Since cancer cells often rely on NHEJ for survival, SCR7 pyrazine was developed to enhance the efficacy of cancer therapies that induce DSB (such as radiotherapy and chemotherapy). A study published in Cell in 2012 showed that SCR7 pyrazine has the potential to be used as a cancer therapeutic, especially when used in combination with DNA damage therapies [1]. - In CRISPR/Cas9-mediated genome editing, SCR7 pyrazine is used as an "NHEJ inhibitor" to redirect DSB repair to homologous recombination repair (HDR), thereby achieving precise integration of donor DNA. A study published in Sci Rep in 2016 showed that SCR7 pyrazine can improve the efficiency of CRISPR/Cas9-based HSV-1 genome editing, providing a tool for constructing recombinant HSV-1 vectors for gene therapy and virology research [2].
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| Molecular Formula |
C18H12N4OS
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|---|---|
| Molecular Weight |
332.38
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| Exact Mass |
332.073
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| Elemental Analysis |
C, 65.05; H, 3.64; N, 16.86; O, 4.81; S, 9.65
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| CAS # |
14892-97-8
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| Related CAS # |
14892-97-8
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| PubChem CID |
10688007
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| Appearance |
Light yellow to yellow solid powder
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| Melting Point |
209 °C
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| LogP |
3.748
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| Hydrogen Bond Donor Count |
2
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| Hydrogen Bond Acceptor Count |
4
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| Rotatable Bond Count |
2
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| Heavy Atom Count |
24
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| Complexity |
487
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| Defined Atom Stereocenter Count |
0
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| SMILES |
S=C1N([H])C(C2=C(N1[H])N=C(C1C([H])=C([H])C([H])=C([H])C=1[H])C(C1C([H])=C([H])C([H])=C([H])C=1[H])=N2)=O
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| InChi Key |
GSRTWXVBHGOUBU-UHFFFAOYSA-N
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| InChi Code |
InChI=1S/C18H12N4OS/c23-17-15-16(21-18(24)22-17)20-14(12-9-5-2-6-10-12)13(19-15)11-7-3-1-4-8-11/h1-10H,(H2,20,21,22,23,24)
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| Chemical Name |
6,7-diphenyl-2-sulfanylidene-1H-pteridin-4-one
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| Synonyms |
SCR-7 pyrazine; SCR7 pyrazine; 14892-97-8; Oprea1_571617; DTXSID90443563; RefChem:366981; DTXCID90394384; SCR7 pyrazine; 6,7-diphenyl-2-sulfanylidene-1H-pteridin-4-one; 6,7-diphenyl-2-thioxo-2,3-dihydropteridin-4(1H)-one; SCR 7 pyrazine
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| HS Tariff Code |
2933598000
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
DMSO: ~66 mg/mL (~198.6 mM)
Ethanol: ~23 mg/mL (~69.2 mM) |
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| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.5 mg/mL (7.52 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 25.0 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. Solubility in Formulation 2: ≥ 2.5 mg/mL (7.52 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 25.0 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. (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 3.0086 mL | 15.0430 mL | 30.0860 mL | |
| 5 mM | 0.6017 mL | 3.0086 mL | 6.0172 mL | |
| 10 mM | 0.3009 mL | 1.5043 mL | 3.0086 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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