My friend is having troubles with her MCF-7 cells. She cultured the cells from frozen cell and has used RPMI + 10% FBS as her media as suggested by the data sheet. The following day, majority of her cells died (but still adhering) which I think it's because of her media which was almost 6 mths old. She has changed her media to DMEM + 10% FBS + 1% Pen but hasn't seen much difference yet. Should she wait for a day more? Or should she just discard it?
ATCC recommends F-12K/10% FBS for these cells. Part of the problem might be the medium. Although these cells might grow in RPMI, the fact that it was so old could have compromised the cells. I would suggest switching to F-12K/10% FBS as soon as possible. Let the cells go for at least a couple of days to see if they will make it.
That being said, the best thing to do is to start a new vial with the correct medium. Since some proportion of the cells died from the first vial, the population may have been altered which could lead to artifacts, especially with continued passage. If most of these cells die also, then the problem could be with the frozen stocks. If that is the case, she might need to get some more from ATCC or somewhere else that guarantees the health of the line.