ACSL4 and breast cancer: However, the results described above, along with our findings showing that the effects of rosiglitazone on breast cancer growth in vitro and in vivo are similar to those obtained with the specific inhibition of ACSL4 by doxycycline treatment in MCF-7 Tet-Off/ACSL4 cells [4], strongly suggest that rosiglitazone effects are due to the inhibition of ACSL4 activity.