hi Jumana,

1-how about check your cell number first, is it high and the ammount of drug may be not enough to block NFKB !!, try also to make titer for the drug and see how this work as well.

2- try to decrease the FBS or do serum starvation for short time !

Thanks Yousef... Actually I started optimizing ,simultaneously, with Luciferase assay (p-55A2) using different drug concentrations but since my experiment is really urgent so I thought finding an already established protocol in HeLa would help to get results sooner. I will consider the serum starvation condition. Thank you so much

You will find useful information inlinks below:

Article Therapeutic potential of inhibition of the NF-??B pathway in...

Article Inhibition of NF-κB/Rel nuclear translocation by dexamethaso...

Article Effect of Dexamethasone on NF-kB Activation, Tumor Necrosis ...

Follow this link may be helpful

https://www.ncbi.nlm.nih.gov/m/pubmed/9679644/

Kind regards