In article <3i9s7o$dtl at dux.dundee.ac.uk>, (k.c.breen at dundee.ac.uk) writes:
> One method to differentiate neuroblastoma cells is to treat the cells with
> retinoic acid (RA). I have seen two protocols; one uses RA in ethanol, the
> other RA in DMSO. Both are made up at a stock of 10-2M and then diluted 1
> in 1000 when treating the cells. Which method is preferable, or is there
> any particular difference? Furthermore, I believe that RA is
> light-sensitive and the solution is unstable. Would anybody have
> suggestions for storage conditions, and is is sensitive to repeated
> freeze-thaw cycles?
I have used retinoic acid to differential N-tera 2 cells in culture. I usually
dissolve an ampule at a time in DMSO. I have no experience with EtOH. I am
told that drugs dissolved in DMSO can be absorbed through the skin, so wear
gloves when handling this RA solution. I similarly use a working solution of
10mM and dilute it to 10uM in my growth media. Retinoic acid is light
sensitive, so I store it covered at -80 degrees. I aliquot my samples into
individual tubes and have not trusted RA that has been thawed and re-frozen. I
have also found that the effeectiveness of RA in differentiating NT2 cells
diminishes after about a month of storage, so only make up enough for a month
of experiments at a time.
I hope this is helpful.
Brian Brooks
University of Pennsylvania School of Medicine
Philadelphia, PA
