Figure 4.

Constitutive Myd88-dependent signaling contributes to tumor growth. In vitro and in vivo growth were examined over time using a stable cell line expressing shRNA specific for Myd88 (_consMyd^low; A, B). Growth was also examined for a cell line expressing shRNA specific for Myd88 under a tetracycline-inducible promoter upon treatment with 2 µg/mL tetracycline in vitro (_indMyd^low, C) or with 0.2 mg/mL doxycycline in vivo (_indMyd^low, D). 4T1 cells treated with 100 µM of a Myd88-specific inhibitory peptide (MP) was also followed for growth over time in vitro (E) and in vivo (F). All data are presented with the appropriate controls (cntrl) and represent the average and standard error of at least three separate experiments. For in vitro growth, where indicated (*), P < 0.05 using Student’s t-test relative to control at the 72-hour time point. For in vivo studies, at least five mice per group were used for each experiment, and where indicated (*), P < 0.05 using two-way ANOVA.