Catalog No.S7261 Synonyms: β-Lapachone, ARQ-501
Molecular Weight(MW): 242.27
Beta-Lapachone is a selective DNA topoisomerase I inhibitor, exhibiting no inhibitory activities against DNA topoisomerase II or ligase. Phase 2.
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|Description||Beta-Lapachone is a selective DNA topoisomerase I inhibitor, exhibiting no inhibitory activities against DNA topoisomerase II or ligase. Phase 2.|
Beta-Lapachone inhibits DNA relaxation induced by DNA topoisomerase I in a dose-dependent manner.  Treatment of beta-lapachone (100 nM or greater) results in >95% inhibition of Topo I DNA unwinding activity compared to the DMSO control. beta-lapachone (1-5 μM) causes a block in G0/G1 of the cell cycle and induces apoptosis by locking Topo I onto DNA and blocking replication fork movement in HL-60 and three human prostate cancer (DU-145, PC-3, and LNCaP) cells.  Beta-Lapachone facilitates the migration of mouse 3T3 fibroblasts and human endothelial EAhy926 cells through different MAPK signaling pathways, and thus accelerates scrape-wound healing in vitro.  In addition, beta-Lapachone inhibits purified recombinant IDO1 activity through uncompetitive inhibition with IC50 of 0.44 μM, and beta-lapachone also exhibits superior retention of intracellular IDO1 inhibitory activity with an IC50 of 1.0 μM, partially dependent on biotransformation by NQO1.  Beta-lapachone induces programmed necrosis of NQO1+ cancer cells by NQO1-dependent reactive oxygen species (ROS) formation and PARP1 hyperactivation. 
|In vivo||Beta-lapachone treatment (50 mg/kg) leads to potent inhibition of in vivo tumor growth in a xenograft mouse model of human ovarian cancer, and the combination of beta-lapachone and taxol produces a synergistic induction of apoptosis.  In normal and diabetic (db/db) mice, treatment of beta-lapachone results in a faster healing process than vehicle only. |
Topoisomerase I Catalytic Actioity Assay :Topoisomerase I Catalytic Actioity Assay: The enzymatic activity is analyzed by the DNA unwinding assay. DNA topoisomerase I, from TopoGEN (1 unit, which is defined as the amount of enzyme that converts 0.5 μg of superhelical DNA to the relaxed state in 30 minutes at 37 °C), is incubated with 0.5 μg of 6x174 RF DNA, in the presence or absence of Beta-Lapachone, in 20 μL of relaxation buffer (50 mM Tris (pH 7.5). 50 mM KCI, 10 mM MgCl2, 0.5 mM dithiothreitol, 0.5 mM EDTA, 30 μg/mL bovine serum albumin) for 30 minutes at 37 °C. Reactions are stopped by adding 1% SDS and proteinase K (50 μg/mL). After an additional 1-hour incubation at 37 °C, the products are separated by electrophoresis in 1% agarose gel in TAE buffer (0.04 M tris acetate, 0.001 M EDTA). The gel is stained with ethidium bromide after electrophoresis. The photographic negative is scanned with an NIH image analysis system.
-  Li CJ, et al. J Biol Chem. 1993, 268(30), 22463-22468.
-  Planchon SM, et al. Cancer Res. 1995, 55(17), 3706-3711.
-  Kung HN, et al. Am J Physiol Cell Physiol. 2008, 295(4), C931-943.
|In vitro||DMSO||33 mg/mL warmed (136.21 mM)|
|Ethanol||10 mg/mL (41.27 mM)|
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