I am treating HepG2 cells with Lipoprotein. I seed cells in serum media (10%). Just before treatment, I change media to serum free media. Should I maintain cells in serum free media for 12 hours prior to the treatment?
I agree that for signalling events serum starvation is frequently pivotal. To see short term signalling such as growth factor receptor activation I prefer to starve the cells for just one or two hours. If I do this overnight the cells have gone into a sort of senescent state and the phosphorylation events are more variable.
If you want to know whether the serum would mask the effect of your treatment or not, I will tell you what I always do with my cell. I work with cytokines (pro-inflammatory cytokines) on cells and it is well known that high concentration of serum affects the effectiveness of those cytokines (in vitro). Therefore, I seed my cells in 5% serum for 24h before I add the cytokines, then I wash the cells three times by serum-free medium and I add my inducer with serum free medium or in 1%. We got clear effect as we expected
Serum is a great amount of cytokines and growth factors among other things. Frequently, we subject the cell to a starving period (8-16hours) after start any treatment with drugs or small molecules.
If your goal are study effects such as phosporilation or other transitory post-translational modification you should subject your cell to starving.
As mentioned for Niyaz Al-sharabi, starving conditions may vary according to the cell type or experimental conditions.
I have been worked if some cells quite sensitive to starving conditions. To solve this issue I did a gradual conditioning of the cell into less amount of serum/daily until obtain cells in serum free.
But you need to remember that in vitro experiments always will show some kind of bias. Try your treatments in serum free compared with the normal media conditions.
I agree that for signalling events serum starvation is frequently pivotal. To see short term signalling such as growth factor receptor activation I prefer to starve the cells for just one or two hours. If I do this overnight the cells have gone into a sort of senescent state and the phosphorylation events are more variable.