Using Carboxyfluorescein Succinimidyl Ester (CFSE) to Measure the Effects of Sulforaphane on Cell Division in a Human Leukemia Cell Line.

Abstract

Sulforaphane (SFN), an organic isoscyanate found in broccoli and other cruciferous vegetables, has been shown to be an important chemopreventitive agent with chemotherapeutic potential. In preliminary experiments we have shown that SFN is cytotoxic to a variety of tumor cell lines including HL‐60, a cell line derived from a patient with acute myeloid leukemia. In order to investigate the mechanism how SFN effects HL‐60 cells, we used CFDA‐SE, a non‐permeable fluorescent molecule, to measure the number of doublings in a population of HL‐60 cells grown in SFN for 96 hours. Once inside the membrane, cellular esterase cleaves off the acetate groups creating Carboxyfluorescein Succinimidyl Ester (CFSE). With each cell division the amount of CFSE is cut in half, which can be observed via flow cytometry. Preliminary experiments compared the effect of different serum concentration with sulforaphane's effect on cell division. Both low serum concentrations and SFN concentrations in the range of 0.1316 mM to 0.2632 mM could inhibit cell division; whereas, SFN concentrations greater than 0.2632 mM caused both growth inhibition and cell death. Cells grown in SFN at a concentration of 0.3948 mM showed 40% survival and fewer divisions. Future research will investigate the mechanism of this growth inhibition and the role of apoptosis induction in the observed toxicity of SFN.