Experimental setup to address the role of JNK signaling in mammary tumor progression and metastasis. MDA231-LM2 or SUM159-LM1 cells were implanted bilaterally into the fourth mammary fat pads of NSG mice. In vivo treatment with the JNK inhibitor CC-401 (JNKi) commenced at day 5 post implantation and was repeated every three days thereafter until analysis. 