Do MCF7 cells need estradiol?

Fred Jacobs f_jacobs at
Thu Sep 7 17:35:48 EST 1995

Do MCF7 human breast cancer cells need estradiol for growth if they are at
very low densities? Our MCF7's grow fine in DMEM + 10% FBS if plated at
>10^4 per ml, but at lower concentrations, they just sit (attached) to the
plate after passaging. Since I am transfecting MCF7 cells with neomycin -
containing expression vectors (by lipofection) and trying to recover
clones expressing our gene, only a tiny fraction of the cells survive G418
selection (at least, by attaching) but then they just don't grow.
Replacing media with conditioned media (media from a confluent MCF7 plate)
doesn't seem to do much. We have successfully transfected lots of other
cell lines with the same DNA construct, so I don't think there's a generic
transfection problem. We've also titrated for G418 toxicity (at about
400ug/ml). I have also heard that, MCF7 being an "old" cell line, there
are lots of uncharacterized variants with different growth requirements. 
Thanks for any suggestions.

Fred Jacobs
Biomira Inc.
f_jacobs at

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