OSMI-4 is a low nanomolar O-GlcNAc transferase (OGT) inhibitor (EC50 of 3 μM in cells) that can be used to study OGT inhibition in different human cell lines.

OGT:3 μM (EC50)

METHODS: HEK293T cells were treated with OSMI-4 (10 μM, 2 hours) and quantitative PCR was performed using primers for the OGT retained intron (intron 4) and spliced ​​exon (exon 4).
RESULTS The bar graph shows that OSMI-4 increases retained intron splicing. [1]
METHODS: HEK293T cells were treated with OSMI-4 (20, 50 μM, 24 hours); HEK293T cells were treated with OSMI-4 (0.1, 1, 5, 5, 10, 20 μM, 2, 24, 48 hours); Western blot analysis of total O-GlcNAc was performed.
RESULTS O-GlcNAc levels were reduced to a greater extent following OSMI-4 treatment; 24 hours of OSMI-4 treatment of HEK293T cells resulted in a dose-dependent decrease in O-GlcNAc levels, with effects seen with only 5 µM of compound treatment, and these effects could be observed in as little as 2 hours or 48 hours. [1]