How to define drug_resistant or drug_sensitive when knowing the IC50 values?

Question

[zero_hsy]

Hello:

I have got the IC50 data for each cell line and drug. For one cell line, how to define the drug is sensitive or resistant towards this cell line?

Could anyone tell me how to define?

Answer 1

[Devon Ryan]

This is probably more appropriate for the biology stackexchange.

"Sensitive" and "insensitive" are dose-dependent descriptors and the relevant dose ranges will depend on the off-target effects (assuming they're even known). If you just have to randomly pick some thresholds, then an IC50 in the pM to nM range would tend to indicate a sensitive line, while IC50 in the µM or higher range is probably insensitive. The reason for this is simply that off-target effects increase with dose. Note that these vague ranges are just ballpark estimates, there necessarily exists no strict definition.

Realistically, if you have a bunch of cell lines and some are likely sensitive to a compound and others not, then simply graphing the IC50 values will likely show you the group structure and whether there's a reasonable discrimination threshold. There are statistical techniques that can be applied here, but they're overkill and you should look at a graph anyway.

If you're not overly familiar with the compounds and/or biological system that you're using then just sit down with a biologist/chemist familiar with the specific project and show him/her the IC50 values. He/she can then give you some insight into reasonable ranges.

[zero_hsy]

Thanks a lot!