THP-1 / HL-60 apoptosis inducing agent

Does anyone know a good, high expression means of inducing apoptosis in
THP-1 or HL-60 monocytes to be detected electrophoreticly?   I have several
protocols for FACS and have run the TUNNEL assay (dUTP),  but am currently
in need of a simple agent to use for obtaining a good apoptotic DNA
laddering effect for a positive controll to be routinely run along-side
various samples.

Any suggestions?

Thank you for your time,

John B. Edgar
Stella Duncan Institute
University of Montana, Missoula