Ibulocydine
Ibulocydine is an isobutyrate prodrug of the Cdk inhibitor BMK-Y101 (HY-188159), with oral activity, and exhibits IC50 values of approximately 50 nM against CDK1/CDK2, 530 nM against CDK7/cyclin H/Mat1, and 85 nM against CDK9/cyclin T. Ibulocydine reduces the phosphorylation levels of Rb, nucleolin, and RNA polymerase II CTD Ser-5 and Ser-2, downregulates the expression of Mcl-1, survivin, and XIAP, decreases MMP-9 expression, and lowers the Bcl-2/Bax ratio, activates calpain-mediated Bax cleavage, cytochrome c release, and caspase activation. Ibulocydine induces apoptosis, inhibits the growth of cancer cells and xenografts, enhances the sensitivity of cancer cells to TRAIL and radiotherapy, and blocks cancer cell metastasis. Ibulocydine can be used in research related to various cancers, including hepatocellular carcinoma, triple-negative breast cancer, lung cancer, and colon cancer.
For research use only. We do not sell to patients.
- CAS No.: 1314096-68-8
- Formula: C16H20BrN5O6
- Molecular Weight:458.26
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Storage:
Please store the product under the recommended conditions in the Certificate of Analysis.
Biological Activity
Description
IC50 & Target
[1]|
CDK1 ~50 nM (IC50) |
CDK2 ~50 nM (IC50) |
CDK7/Cyclin H/MAT1 530 nM (IC50) |
CDK9/cyclinT1 85 nM (IC50) |
Cellular Effect
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Cell Line
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Type | Value | Description | References |
|---|---|---|---|---|
| SNU-354 | IC50 |
0.45 μM
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Inhibition of Cdk7-mediated Ser-5 phosphorylation of RNA polymerase II in human HCC SNU-354 cells assessed via Western blot analysis after 24 h incubation.
Inhibition of Cdk7-mediated Ser-5 phosphorylation of RNA polymerase II in human HCC SNU-354 cells assessed via Western blot analysis after 24 h incubation.
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21478145 |
| SNU-354 | IC50 |
0.33 μM
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Inhibition of Cdk9-mediated Ser-2 phosphorylation of RNA polymerase II in human HCC SNU-354 cells assessed via Western blot analysis after 24 h incubation.
Inhibition of Cdk9-mediated Ser-2 phosphorylation of RNA polymerase II in human HCC SNU-354 cells assessed via Western blot analysis after 24 h incubation.
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21478145 |
| Hs-578T | IC50 |
3.07 μM
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Cytotoxicity against human Hs578T triple-negative breast cancer cells assessed as reduction in cell viability incubated for 24 hrs by CCK-8 assay.
Cytotoxicity against human Hs578T triple-negative breast cancer cells assessed as reduction in cell viability incubated for 24 hrs by CCK-8 assay.
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38892310 |
| MDA-MB-231 | IC50 |
4.64 μM
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Cytotoxicity against human MDA-MB-231-Luc triple-negative breast cancer cells assessed as reduction in cell viability incubated for 24 hrs by CCK-8 assay.
Cytotoxicity against human MDA-MB-231-Luc triple-negative breast cancer cells assessed as reduction in cell viability incubated for 24 hrs by CCK-8 assay.
|
38892310 |
| MDA-MB-435S | IC50 |
3.25 μM
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Cytotoxicity against human MDA-MB-435S triple-negative breast cancer cells assessed as reduction in cell viability incubated for 24 hrs by CCK-8 assay.
Cytotoxicity against human MDA-MB-435S triple-negative breast cancer cells assessed as reduction in cell viability incubated for 24 hrs by CCK-8 assay.
|
38892310 |
In Vitro
Ibulocydine (0-50 μM; 18-24 h) dose-dependently inhibits the viability of SK-HEP-1, HepG2, and SNU-354 cells and suppresses DNA synthesis in SNU-354 cells[1].
Ibulocydine (0.1-50 μM; 24 h) inhibits Cdk7-mediated RNA polymerase II Ser-5 phosphorylation and Cdk9-mediated RNA polymerase II Ser-2 phosphorylation in SNU-354, SK-HEP-1, and HepG2 cells; the corresponding IC50 values in SNU-354 cells are 0.45 μM and 0.33 μM, respectively, with minimal effects on total RNA polymerase II levels[1].
Ibulocydine (50 μM; 6-12 h) inhibits Cdk1-mediated nucleolin phosphorylation by approximately 50% within 12 h and suppresses Cdk2-mediated Rb phosphorylation by about 50% within 6 h in human hepatocellular carcinoma SNU-354 cells[1].
Ibulocydine (10 μM; 6-24 h) time-dependently reduces the mRNA and protein levels of Mcl-1, survivin, and XIAP in SNU-354, SK-HEP-1, and HepG2 cells[1].
Ibulocydine (50 μM; 6 h) induces PARP cleavage (a marker of apoptosis) in SNU-354, SK-HEP-1, and HepG2 cells[1].
Ibulocydine (0.1-50 μM; 24 h) dose-dependently activates caspase-3 activity in SNU-354 cells[1].
Ibulocydine (10-50 μM; 12 h) increases the sub-G1 apoptotic cell population in SNU-354, SK-HEP-1, and HepG2 cells in a dose- and time-dependent manner, but has no effect on the sub-G1 cell population in normal mouse hepatocytes AML-12[1].
Ibulocydine (24 h) reduces the viability of Hs578T, MDA-MB-231-Luc, and MDA-MB-435S cells in a dose-dependent manner, with IC50 values of 3.07 μM, 4.64 μM, and 3.25 μM, respectively[2].
Ibulocydine (1-3 μM; 12 h exposure followed by 9 days of incubation) inhibits long-term colony formation in Hs578T, MDA-MB-231-Luc, and MDA-MB-435S cells[2].
Ibulocydine (0.25-3 μM; 24 h) induces dose-dependent increases in cleaved caspase-3 and cleaved PARP in Hs578T, MDA-MB-231-Luc, and MDA-MB-435S cells, and decreases the expression of anti-apoptotic proteins XIAP, Bcl-xL, survivin, and Mcl-1, as well as dose-dependent reductions in the protein levels of MMP-2, MMP-9, Snail 1/2, TWIST, and ZEB1[2].
Ibulocydine (3 μM; 24 h) induces apoptotic cell death in Hs578T, MDA-MB-231-Luc, and MDA-MB-435S cells[2].
Ibulocydine (50-100 nM; 24 h) sensitizes TRAIL-resistant human hepatocellular carcinoma cells Hep3B and SK-Hep1 to TRAIL-induced caspase-dependent apoptosis, and synergistic cell death is observed upon combined treatment[3].
Ibulocydine (0.05 μM) inhibits Cdk7/Cdk9 activity in Hep3B cells, and co-treatment with TRAIL induces apoptosis in Hep3B and SK-Hep1 cells through calpain-mediated Bax cleavage[3].
Ibulocydine (50-100 nM; 24 h) enhances the sensitivity of human hepatocellular carcinoma cells Hep3B and SK-Hep1 to TRAIL through calpain activation, which mediates Bax cleavage and subsequent caspase-dependent apoptosis[3].
Combined treatment with ibulocydine (50 nM; 24 h) and TRAIL induces apoptosis in human hepatoma Hep3B cells overexpressing Bcl-xL, and this effect is not blocked by Bcl-xL overexpression[3].
Ibulocydine (0.4-0.8 μM, 30 min followed by 10 Gy radiotherapy, with a total incubation time of 24 h) induces caspase-dependent apoptosis in human lung cancer A549 cells and human colon cancer RKO cells through the cleavage of caspase-3, caspase-9, and PARP[4].
Ibulocydine (0.1-1 μM; 16-24 h) inhibits RNA polymerase II phosphorylation at Ser-2 and Ser-5 sites and regulates Bcl-2 and Bax expression at the transcriptional level in a dose-dependent manner; in human lung cancer A549 cells and human colon cancer RKO cells, its combination with radiotherapy reduces the Bcl-2/Bax ratio[4].
Ibulocydine (1-3 μM; 24 h) inhibits the migration of Hs578T and MDA-MB-231-Luc cells in a dose-dependent manner; at (0.5-1 μM), it inhibits the migration of MDA-MB-435S cells[2].
Ibulocydine (0.5-1 μM; 24 h) inhibits the invasion of Hs578T, MDA-MB-231-Luc, and MDA-MB-435S cells in a dose-dependent manner[2].
Combined treatment with ibulocydine (50-100 nM; 24 h) and TRAIL induces apoptosis in Hep3B and SK-Hep1 human hepatocellular carcinoma cells through mitochondrial translocation of cleaved Bax, which mediates MMP loss and cytochrome c release[3].
Ibulocydine (0.4-0.8 μM; pretreatment for 30 min before 10 Gy radiotherapy, with a total incubation time of 24 h) induces significant mitochondrial dysfunction in human lung cancer A549 cells and human colon cancer RKO cells, including MMP loss and cytochrome c release, and its effect depends on the downregulation of Bcl-2 expression levels[4].
Ibulocydine (24 h) synergizes with radiotherapy to reduce the viability of A549, RKO, Hep3B, and MCF-7 cells; among these, the viability inhibitory effect begins at 1 μM in A549 cells and at concentrations above 0.8 μM in RKO cells[4].
Ibulocydine (0.4-0.8 μM; pretreatment for 30 min before 10 Gy radiotherapy, with a total incubation time of 24 h) increases sub-G1 cell accumulation in human lung cancer A549 cells and human colon cancer RKO cells[4].
MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only. Further protocols information, click here.
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Cell Line:human HCC SNU-354, SK-HEP-1, HepG2 cells
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Concentration:0.1, 0.5, 1, 5, 10, 50 μM (24 h incubation); 10 μM (6, 12, 18, 24 h incubation)
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Incubation Time:24 h (0.1-50 μM); 6-24 h (10 μM)
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Result:Inhibited Cdk7-mediated Ser-5 phosphorylation of RNA polymerase II with an IC50 of 0.45 μM in SNU-354 cells.
Inhibited Cdk9-mediated Ser-2 phosphorylation of RNA polymerase II with an IC50 of 0.33 μM in SNU-354 cells, with greater potency than comparison compounds.
Reduced Ser-5 and Ser-2 phosphorylation in a time-dependent manner in SK-HEP-1 and HepG2 cells, with greater efficacy than parent compound BMK-Y101.
Left total RNA polymerase II levels minimally affected.
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Cell Line:human HCC SNU-354, SK-HEP-1, HepG2 cells, mouse normal hepatocyte AML-12 cells
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Concentration:0.1, 0.5, 1, 5, 10, 50 μM (24 h incubation); 50 μM (6, 12, 18, 24 h incubation); 10, 50 μM (12 h incubation)
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Incubation Time:24 h (0.1-50 μM); 6-24 h (50 μM); 12 h (10-50 μM)
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Result:Increased the sub-G1 population in dose- and time-dependent manners in SNU-354 cells, with greater efficacy than parent compound BMK-Y101.
Increased the sub-G1 population in SK-HEP-1, HepG2, and SNU-354 cells after treatment with 10 or 50 μM for 12 h.
Caused no increase in the sub-G1 population in AML-12 normal hepatocyte cells.
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Cell Line:human TNBC cell lines Hs578T, MDA-MB-231-Luc, and MDA-MB-435S
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Concentration:1 μM, 3 μM
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Incubation Time:12 h exposure followed by 9 days of incubation
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Result:Inhibited long-term survival by reducing the number of colonies formed in all three TNBC cell lines.
Showed greater inhibition at the 3 μM dose compared to the 1 μM dose.
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Cell Line:human TNBC cell lines Hs578T, MDA-MB-231-Luc, and MDA-MB-435S
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Concentration:0.25 μM, 0.5 μM, 1 μM, 3 μM
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Incubation Time:24 h
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Result:Increased cleavage levels of caspase-3 and PARP in a dose-dependent manner.
Reduced protein levels of anti-apoptotic proteins XIAP, Bcl-xL, survivin, and Mcl-1 in a dose-dependent manner.\nReduced protein levels of MMP-2, MMP-9, and mesenchymal markers Snail 1/2, TWIST, and ZEB1 in a dose-dependent manner across all three TNBC cell lines.
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Cell Line:human TNBC cell lines Hs578T, MDA-MB-231-Luc, and MDA-MB-435S
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Concentration:0.5 μM, 1 μM
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Incubation Time:24 h
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Result:Significantly reduced the number of invading cells in a dose-dependent manner across all three TNBC cell lines.
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Cell Line:A549 cells, RKO cells
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Concentration:0.8 μM (A549 cells); 0.4 μM (RKO cells)
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Incubation Time:30 min pretreatment before 10 Gy radiotherapy; 24 h total incubation
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Result:Did not increase sub-G1 phase cell accumulation when used alone.
Did not increase sub-G1 phase cell accumulation when radiotherapy was used alone.
Significantly increased sub-G1 phase cell accumulation in both A549 and RKO cells when combined with radiotherapy.
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Cell Line:A549 cells, RKO cells
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Concentration:0.8 μM (A549 cells); 0.4 μM (RKO cells)
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Incubation Time:30 min pretreatment before 10 Gy radiotherapy; 24 h total incubation
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Result:Induced only small amounts of Annexin V-positive cells when used alone.
Induced only small amounts of Annexin V-positive cells when radiotherapy was used alone.
Markedly increased Annexin V-positive cells, reaching ~20% in both A549 and RKO cells, when combined with radiotherapy.
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Cell Line:A549 cells, RKO cells
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Concentration:0.8 μM (A549 cells); 0.4 μM (RKO cells)
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Incubation Time:30 min pretreatment before 10 Gy radiotherapy; 24 h total incubation
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Result:Did not induce cleavage of caspase-3, caspase-9, or PARP when used alone.
Did not induce cleavage of caspase-3, caspase-9, or PARP when radiotherapy was used alone.
Induced cleavage of caspase-3, caspase-9, and PARP in both A549 and RKO cells when combined with radiotherapy, while precursor levels of caspase-8 remained unchanged.
Blocked cell death induced by the combined treatment when pre-treated with the pan-caspase inhibitor zVAD-fmk.
In Vivo
Ibulocydine (100 μg per mouse; intrathecal injection; once every 3 days for a total of 3 doses) combined with radiotherapy significantly delays tumor growth in A549 xenograft mice, accompanied by decreased Bcl-2 expression, without causing body weight loss[4].
Ibulocydine (3 µM; in vitro pretreatment; 6 h) inhibits lung metastasis of triple-negative breast cancer cells in a mouse model, as evidenced by persistently lower total flux of luciferase at day 56 and reduced tumor burden in the lungs[2].
MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.
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Animal Model:athymic nude mice (male, 5-6 weeks old, subcutaneous xenograft of SNU-354 human HCC cells)[1]
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Dosage:4 mg/kg; 20 mg/kg
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Administration:i.p.; five times weekly; 3 weeks
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Result:Suppressed SNU-354 xenograft growth by 15% at 4 mg/kg.
Suppressed SNU-354 xenograft growth by 47% at 20 mg/kg.
Induced apoptosis in xenografted HCC cells in a dose-dependent manner.
Caused no change in body weight.
Detected no apoptosis in normal liver tissues.
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Animal Model:BALB/c nude mice (female, 6 weeks old, experimental lung metastasis model via intravenous injection of MDA-MB-231-Luc cells)[2]
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Dosage:3 µM
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Administration:in vitro pretreatment; 6 h
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Result:Maintained luciferase total flux near baseline throughout 56-day observation period.
Reduced lung tumor burden markedly at study endpoint compared to control mice.
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Animal Model:Balb/c nude (male, 5-week old)[4]
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Dosage:100 μg/mouse
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Administration:i.t.; 3 times at 3-day intervals; administered 2 hours prior to radiotherapy
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Result:Induced marked tumor growth delay, with tumor growth almost halted for 15 days.
Showed no body weight loss.
Reduced Bcl-2 protein levels significantly in tumor specimens compared to controls.
Chemical Information
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CAS No. 1314096-68-8
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Molecular Weight 458.26
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Formula C16H20BrN5O6
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SMILES
O=C(C(C)C)OC[C@H]1[C@@H](O)[C@H](O)[C@@H](N2C3=NC(Br)=C(C3=C(N)N=C2)C(N)=O)O1
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Shipping
Room temperature in continental US; may vary elsewhere.
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Storage
Please store the product under the recommended conditions in the Certificate of Analysis.
Protocols
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Western Blot
Western blotting (WB) is a commonly used experimental method in molecular biology, biochemistry, and immunogenetics for identifying and quantifying target proteins. It combines gel electrophoresis with immunoassay, enabling researchers to analyze protein expression, post-translational modifications, and molecular weight.
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RNA extraction experimental
By lysing cells, releasing RNA, and removing impurities such as proteins and DNA, high-purity RNA products are finally obtained. The commonly used traditional method is the guanidine isothiocyanate/phenol/chloroform method (Trizol), which is suitable for a variety of animal materials including animal tissues, microorganisms, cultured cells, etc., and most plant materials.
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Mitochondrial membrane-potential fluorescent assay
Mitochondrial membrane potential fluorescent assays estimate ΔΨm in living cells using lipophilic cationic dyes such as TMRM, TMRE, rhodamine 123, and JC-1, which accumulate in mitochondria according to membrane polarization; loss of signal after FCCP or CCCP treatment is interpreted as mitochondrial depolarization. TMRM/TMRE and rhodamine 123 are commonly used for semi-quantitative live-cell microscopy or flow cytometry, while JC-1 can report a shift from red aggregate fluorescence to green monomer fluorescence during depolarization; interpretation requires controls because dye concentration, quenching mode, cell type, dye efflux, and mitochondrial mass can affect fluorescence independently of ΔΨm.
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Annexin V plus membrane-impermeant dye apoptosis staining
Annexin V-based apoptosis assays rely on the detection of phosphatidylserine (PS) externalization from the inner leaflet of the plasma membrane to the outer leaflet, an early biochemical hallmark of apoptosis. Fluorescently labeled Annexin V binds PS in a calcium-dependent manner, enabling identification of early apoptotic cells by flow cytometry or fluorescence microscopy. When combined with a membrane-impermeant DNA-binding dye (e. g. , propidium iodide), this approach allows discrimination between viable (Annexin V−/dye−), early apoptotic (Annexin V+/dye−), and late apoptotic or necrotic (Annexin V+/dye+) cell populations by assessing membrane integrity and PS exposure.
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Liver Cancer Modeling
Liver cancer can be classified into primary liver cancer and secondary liver cancer. Secondary liver cancer is the metastatic liver cancer. Primary liver cancer includes hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (ICC) and fibrolamellar HCC, of which HCC is the most common form, accounting for approximately 90% of primary liver cancers[1]. HCC mouse models include chemical agent-induced models, transplanted tumor models, and genetic engineered models.
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Breast Cancer Modeling
Breast cancer is a heterogeneous cancer, and it has been distinguished into four subtypes: luminal A, luminal B, HER2-positive and basal-like. Molecular mutations, epigenetic alterations, hormone exposure and immune microenvironment are related to the progression of breast cancer.
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Kinase activity and phosphorylation assays
Kinase activity assays measure the ability of kinases to transfer phosphate groups from ATP to specific substrates, while phosphorylation assays detect the presence and levels of phosphorylated proteins. Common methods include radiolabeled ATP incorporation (e. g. ,), ADP release detection via bioluminescence (e. g. ,[3]), enzyme-linked immunosorbent assays (ELISA) for phospho-specific epitopes (e. g. ,[6]), and microtiter-based formats for high-throughput screening (e. g. ,[8]). The ADP-Glo assay quantifies kinase activity by measuring ADP produced during phosphorylation using a luciferase-based system. Radiometric assays involve autoradiography or scintillation counting after incorporation of 32P-labeled ATP into substrate proteins. ELISA-based approaches rely on phospho-specific antibodies to detect activated kinases in cell lysates or purified samples.
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Apoptosis
Apoptosis, also called programmed cell death, is generally characterized by distinct morphological characteristics.
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TUNEL staining for apoptotic DNA fragmentation
TUNEL staining detects DNA strand breaks by using terminal deoxynucleotidyl transferase to add labeled nucleotides to exposed 3′-OH DNA termini, generating either microscopic staining in fixed cells or tissue sections, or fluorescence/cytometric signal in cell suspensions. TUNEL positivity reflects DNA fragmentation but should not be interpreted alone as definitive apoptosis, because TUNEL can also label necrotic, autolytic, mechanically damaged, or DNA-repair-associated DNA breaks.
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Cell Cytotoxicity Assay
Cytotoxicity assays are usually based on the assessment of cell membrane damage, which can also be indirectly detected by measuring cell viability. Detection methods include MTT assay, CKK-8 assay, LDH assay and ATP assay, etc.
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Mitochondrial membrane-potential and mitochondrial mass staining
Mitochondrial membrane potential staining measures the electrochemical polarization across the mitochondrial inner membrane in live cells using lipophilic cationic fluorescent probes; early rhodamine-based work showed that selective mitochondrial dye accumulation is lost when the mitochondrial transmembrane potential is dissipated. JC-1 reports mitochondrial polarization by shifting from green monomer fluorescence to red J-aggregate fluorescence as dye concentration increases within energized mitochondria; therefore, the red/green fluorescence ratio is used as a relative readout of mitochondrial membrane potential. TMRE or TMRM staining provides a single-channel relative readout because these cationic rhodamine esters accumulate in polarized mitochondria, and lower fluorescence indicates reduced mitochondrial polarization when acquisition and dye-loading conditions are controlled. Mitochondrial mass staining is commonly performed with MitoTracker Green FM or related MitoTracker dyes as
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Apoptosis Solutions
Apoptosis is a regulated, generally non-lytic cell-death pathway that removes unwanted, damaged, infected, or abnormal cells through coordinated morphological changes, caspase activation, DNA fragmentation, and membrane remodeling. The intrinsic apoptosis pathway is controlled mainly by mitochondrial outer membrane permeabilization, BCL-2 family proteins, cytochrome c release, apoptosome formation, caspase-9 activation, and downstream executioner caspase-3/7 activation. The extrinsic apoptosis pathway is initiated by death receptors such as Fas, TNFR, and TRAIL receptors, which recruit adaptor proteins and activate caspase-8 before engaging executioner caspases or mitochondrial amplification through BID cleavage. Apoptosis is linked to many phenotypes, including cancer cell killing, tissue homeostasis, immune regulation, neurodegeneration, infection response, and treatment-induced cytotoxicity; unresolved questions include how apoptosis interacts with necroptosis, pyroptosis, ferroptos
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Protocol for Kinase activity and phosphorylation assays
Kinase activity assays measure transfer of phosphate from ATP to a protein or peptide substrate, generating phosphorylated substrate, ADP, or incorporated radiolabeled phosphate as the readout; phosphorylation assays measure site-specific phosphorylation in cells or tissues as a proxy for kinase-pathway activation, inhibition, or substrate regulation. Phosphorylation can be detected by phospho-specific Western blot, immunoprecipitation kinase assay, phospho-immunofluorescence, phospho-flow cytometry, luminescent ADP detection, radiolabeled ATP incorporation, or reporter-based pathway assays, and these readouts can be applied to cancer cells, primary neurons, mouse tumors, organoids, inflammatory macrophages, ferroptosis studies, and mitophagy studies when the kinase target is biologically relevant.
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Orthotopic Cell-Line Xenograft
Orthotopic cell-line xenograft models involve implantation of human cancer cell lines into the anatomically corresponding organ of immunodeficient mice to reproduce tumor growth within a native microenvironment, enabling more clinically relevant tumor behavior compared with subcutaneous models. These models are widely used because orthotopic placement better recapitulates tumor progression, including invasion and metastatic spread, which are often underrepresented in heterotopic implantation systems. Compared with conventional xenografts, orthotopic implantation is described as more technically complex but provides improved simulation of tumor-microenvironment interactions and metastatic behavior, making it particularly valuable for translational oncology research. Surgical orthotopic implantation approaches have been emphasized as enabling faithful reproduction of clinical cancer features, including metastasis and disease progression patterns that align with the tumor’s organ of origi
Purity & Documentation
References
Calculators
Concentration (start) × Volume (start) = Concentration (final) × Volume (final)