LY333531 is a β-specific protein kinase C inhibitor. It competitively and reversibly inhibits PKCβ1 and PKCβ2 with IC50 values of 4.7 and 5.9 nM respectively.

Alantolactone, a naturally occurring eudesmane-type sesquiterpene lactone (SL), could induce activin/SMAD3 signaling and disrupt Cripto-1/activin receptor type II A interaction.