Figure 2

BORG induces the reactivation of proliferative programs and outgrowth of latent D2.OR cells both in vitro and in vivo. (a–c) Constitutive BORG expression (a) dramatically induced D2.OR organoid growth in 3D-cultures as determined by longitudinal bioluminescent assays (b; mean ± SEM; *P < 0.05) and phase contrast microscopy (c; 100X). (d and e) BORG promoted cell cycle progression in D2.OR cells propagated in 3D-cultures (d; mean ± SEM; *P < 0.05; **P < 0.01), but not in 2D-cultures (e). Grey shading indicates overlapping cell cycle distribution. (f and g) Quantification (f) and representative bioluminescent images (g) of parental (empty vector) or BORG-expressing D2.OR cells in the lungs of BALB/c mice (mean ± SEM; *P < 0.05). (h and i) Representative images (h) and quantification (i) of lungs and surface metastases produced by parental and BORG-expressing D2.OR cells from Panels h-j (mean ± SEM; **P < 0.01). (j) H&E, Ki-67, or isotype IgG control-stained tumor sections of lungs of BALB/c mice inoculated with BORG-expressing D2.OR cells.