Is there anybody who is doing MTT assay with M NFS 60 cells for GCSF

Hey even i have trouble with the MNSF 60 cells. I am trying to use them for GCSF assay using MTT protocol but unfortunately dont see any colour after incubating with MTT.
Does any one have a protocol thats working to share with me.

We use Cell Titer Blue (Promega) for our M-NFS-60 prolif assays, but you need a fluorescence plate reader for better dynamic range. Still, it can be used with visible wavelengths. 10K cells/well in 96-well plates for 72hrs, then 3hrs with CTB before reading.