Research Area
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Description
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Cancer |
Biological Activity
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Description
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BSI-201 (Iniparib, SAR240550) is a PARP1 inhibitor. |
Targets
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IC50 |
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In Vitro
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BSI-201 is described as a prodrug of 4-iodo-3-nitrosobenzamide, an agent that covalently inhibits PARP1 by binding to its first zinc finger under cell-free conditions. Treatment of 120 μM BSI-201 plus buthionine sulfoximine (BSO) induces a 95% cell death among 855-2 cells, and displays a similar effect in other human cancer cells. [1] BSI-201 inhibits the growth of E-ras 20 cells, the effect of which can be augmented 4-fold when BOS is added. [2] Recently BSI-201 shows no ability to inhibit PARP enzymatic or cellular activity, but can non-selectively modify cysteine-containing proteins in tumor cells, suggesting the mechanism of action for BSI-201 is likely not via inhibition of PARP activity. [3] BSI-201 (100 μM) inhibits ionizing radiation-induced single-strand breaks (SSBs) repair in human lymphoid cell lines based on large endogenous Epstein–Barr virus (EBV) circular episomes assay, resulting in 55% repair by 2 hours, which can be reversed surprisingly by knockdown of PARP1, indicating that the mechanism of inhibition does not involve trapping PARP at SSBs. [4] BSI-201 is not able to selectively kill homologous recombination (HR)-deficient cells between BRCA2-deficient PEO1 and BRCA2-revertant PEO4, or ATM-deficient GM16666 and ATM-restored GM16667 fibroblasts. Although able to modestly sensitize cells to etoposide, BSI-201 fails to sensitize SKOV3 cells to topoisomerase I poisons, cisplatin, gemcitabine, or paclitaxel, or inhibit pADPr formation in situ at concentrations up to 100 μM. In contrast, BSI-201 is cytotoxic to a variety of cell lines at concentrations above 40 μM reflecting a mechanism independent of PARP. [5] |
In Vivo
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Clinical Trials
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Features
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Combination Therapy
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Description
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A Phase II study to assess the effect of BSI-201 in combination with gemcitabine/cisplatin in non-small cell lung cancer has been completed. |
Protocol
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Cell Assay
[3]
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Cell Lines |
MDA-MB-231, and MDA-MB-436 |
Concentrations |
Dissolved in DMSO, final concentrations ~10 μM |
Incubation Time |
5, and 9 days |
Methods |
Cells are exposed to various concentrations of BSI-201 for 5, and 9 days in the presence or absence of buthionine sulfoxamide (BSO). After treatment, cell proliferation is measured by CellTiter-Glo assay. |
References |
[1] Mendeleyev J, et al. Biochem Pharmacol, 1995, 50(5), 705-714.
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[2] Bauer PI, et al. Biochem Pharmacol, 2002, 63(3), 455-462.
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[3] Liu X, et al. Clin Cancer Res, 2012, 18(2), 510-523.
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[4] Ma W, et al. Proc Natl Acad Sci U S A, 2012, 109(17), 6590-6595.
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[5] Patel AG, et al. Clin Cancer Res, 2012, 18(6), 1655-1662.
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