MCF-7 cells dying after siRNA transfection + estrogen - (Aug/28/2009 )

Hi,
I am struggling with a serious problem: after siRNA transfection MCF-7 cells die.

Since I want to treat the cells with estrogen later on, I usually grow them for 2-3 days in phenol-free medium containing 10% charcoal-stripped FCS. Then I transfect the cells with siRNA using lipofecatmine RNAiMax and leave the transfection mix on the cells. After 1 day cells do not look great.

however, after siRNA transfection with normal medium, normal FCS cells are OK, while after siRNA transfection in the steroid-free medium cells die. Has anybody an idea what can be improved?

Many thanks,
eeri

What happens if you culture the cells in the stripped medium and don't transfect them? Do they also die? Maybe you should also look into a different transfection reagent, or using less of your current lipofectamine, since transfection stresses cells.