ITSA-1 is membrane permeable and specifically suppresses TSA inhibition of HDAC (histone deacetylase), but shows no activity towards other HDAC inhibitors.

A549 cells ( 75% confluent) in 10-cm dishes are treated with DMSO (0.1%), TSA (500 nM), or tubacin (2 μM) for 4.5 h, and then either DMSO (0.1%) or ITSA1 (50 μM) is added for an additional 17.5 h. Samples are rinsed in PBS, trypsinized, and fixed for 2 h in 70% ethanol 30% PBS (4°C). Cells then are washed once in PBS and stored overnight in PBS (4°C).(Only for Reference)