– MCI-INI-3 is a potent, selective, competitive inhibitor of ALDH1A3 (Ki=0.55 uM), shows poor inhibitory effect on the structurally related isoform ALDH1A1 (>140-fold selectivity).MCI-INI-3 also displays on inhibition against six isoforms of ALDH (ALDH16A1, ALDH7A1, ALDH9A1, ALDH2, ALDH1B1, ALDH18A1).MCI-INI-3 demonstrates selective binding to ALDH1A3 in glioma stem cell lysates, inhibits ALDH activity and affects RA synthesis in cells.