Chemical structure of etoposide.
Western blot analysis of extracts from Jurkat cells, untreated (-) or etoposide-treated (25 μM, overnight; +), using Cleaved PARP (Asp214) (D64E10) XP® Rabbit mAb #5625 (upper) or total PARP Antibody #9542 (lower).
Etoposide is supplied as a lyophilized powder. For a 50 mM stock, reconstitute the 5.9 mg in 200 µl DMSO. Working concentrations and length of treatments vary depending on the desired effect, but it is typically used at 5-50 µM for 4-24 hr. Soluble in DMSO at 100 mg/ml; very poorly soluble in ethanol and water with maximum solubility in water ~20-50 µM.
Store lyophilized or in solution at -20ºC, desiccated. In lyophilized form, the chemical is stable for 24 months. Once in solution, use within 3 months to prevent loss of potency. Aliquot to avoid multiple freeze/thaw cycles.
An anti-tumor agent that is commonly used as an apoptosis inducer, etoposide (VP-16) is a topoisomerase II inhibitor with an IC50 of 59.2 µM (1). Etoposide stabilizes a covalent topoisomerase II-cleaved DNA intermediate complex in the catalytic cycle of the enzyme, leading to genomic instability and cell death (2,3). This mechanism of action has been shown to delay progression of the cell cycle through the late S and early G2 phase (4,5).
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