I will be determing the expression of apoptosis proteins in MDA-MB-231 cells upon drug treatment. What is the optimal number of cells usually used to get good protein concentration?
If you are doing western blot for determining proteins the number of the cells you need depended on some factors. The first is method of harvesting the cells. Let's say you are harvesting and treating the cells in 6 well place. Next factor is possible toxicity of the treatment or effect of the treatment on cell proliferation rate that will defined your final confluency. The last but not the least factor is how many western blot you are going to do. Let's say you are detecting 2 proteins that have different molecular weight (for example one is 60 KDa and another one is 13 kDa), then you need to run your lysate two times in different percentages of Gels.
If you give us some more information about your harvesting method and number of the proteins and their molecular weights that you are looking for, I would be more than happy to help.
You don't say how much protein you need or how you lyse the cells, but we get >100 ug of protein from 106 cells from this cell line. You just scale up proportionately to get more. It does depend on the lysis method used.