PARP as measurement of apoptosis - (Mar/10/2006 )

Hi,

I'm trying to evaluate apoptosis in my cells, after treatment with drugs (like etoposide, and camptotecin). I see diferences in the growth, but when I try to see the activation of PARP (poly(ADP-ribose) polymerase), I don't see any diferences, between the samples and the controls. Has it ever happened to anyone?
I'm thinking that maybe PARP has any other post-transcriptional modification that I can´t detect with the antibody. Does anyone know something about that?
I already made a quick search on the net but I can't find anything about that.
Can anyone help me?

Thanks

pals

Any suggestions?

PARP cleavage is generally the indicator of apoptosis you are looking for on a western blot. I have never had much luck using cleaved PARP, and instead use other measures such caspase-3 activity and TUNEL staining. If a flow cytometer is available I would also recommend trying an AnnexinV assay.

As for post-translational modifications of PARP, I don't believe that would be the definitive measurement of apoptosis you seek.