Re: Apoptotic assay for fibroblasts

From: William Telford (TelfordW@mail.nih.gov)
Date: Tue Feb 12 2002 - 12:45:26 EST


Hello Ger...

A significant problem with detecting apoptosis in adherent cell lines is
cell damage associated with removal from their substrate - scraping or
trypsinization can alter annexin V binding and membrane permeability,
muddying up your cell death assay.  If you have access to a laser scanning
cytometer (LSC), you can do "flow" analysis on the cells in the adherent
state - we find this gives a much cleaner assay.  "Late" apoptotic cells
will round up and release from the slide, but cells with "earlier" markers
(such as annexin V binding, caspase activation, 7-AAD permeability) are
still attached and can be detected.

In our hands, serum removal induces cell cycle arrest but not apoptosis (at
least not soon enough!) in murine fibroblasts.  A protein transcription or
translation inhibitor (such as actinomycin D or cycloheximide) induces
apoptosis in these cells and may make a useful positive control -
cycloheximide at 10 ug/ml within 4 hours, actinomycin D at 5 ug/ml within
12 hours.

Regards,

Bill Telford
NCI-NIH

  At 11:29 AM 2/12/2002 +0100, Gerard Bowe wrote:

>Hello everyone,
>
>We are looking for a reliable apoptotic assay for Balb/c 3T3
>(fibroblasts). We have tried the Annexin V FITC/PI with little success.
>After inducing apoptosis by serum removal we get PI +ve, but FITC -ve.
>We've tried various methods of inducing apoposis, but got little or no
>FITC +ve. We detach the cells using trypsin.
>
>Any suggestions/ help would be appreciated.
>
>
>Thanking you,
>Ger



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