Figure 5. Inhibition of gap junction activity controls brain metastatic outgrowth.

a, Dye transfer from astrocytes to MDA231-BrM2 cells in the presence of the indicated concentrations of Tonabersat (Tona) or meclofenamate (Meclo). (n ≥ 3 independent experiments). b, ELISA of IFNα and TNFα in conditioned media from co-cultured MDA231-BrM2 cell and astrocytes in the presence of Tonabersat (Tona) or meclofenamate (Meclo) ranging from 0.5 – 4 × 10⁻⁴ M Tona or 0.25 – 2 × 10⁻⁴ M Meclo. All graphs shown are mean ± S.E.M. (Data shown from 2 independent experiments with 4 replicates each). c, Tonabersat or meclofenamate was administered daily starting one day after cancer cell inoculation in mice. Brain metastatic lesions were quantified based on BLI. (n=2 independent experiments; 8 mice total per group). d, GFP staining of 14-day brain metastatic lesions. Representative images show large, progressive lesions. DAPI, nuclear staining. Scale Bar, 40μm. (n=10 mice). e,f,g, 14 days after inoculation with MDA231-BrM2 cells transduced with inducible control, CX43 or PCDH7 shRNAs, mice were treated with doxycycline and carboplatin. Representative images of matched ex vivo brain BLI and red fluorescence imaging (e). Brain metastatic lesions were quantified based on BLI (f). (2 independent experiments with n= 10 total mice per group). g, 14 days after inoculation with MDA231-BrM2 cells, mice were treated with Tonabersat, meclofenamate, and carboplatin. Following the indicated regimens, brain metastatic lesions were quantified based on BLI (i). (2 independent experiments with n=9 mice total per group).