Figure 5
Inhibition of B16 melanoma cells growth in GABARAP KO mice and a working model to explain these results. (a) Still pictures taken from sacrificed Wt and GABARAP KO mice at the seventeenth day after the inoculation of 2.5 × 105 B16 melanoma cells. Scale bars=10 mm. (b) Growth curve of B16 melanoma cells in Wt and KO mice. Values are representative of 12 mice and are shown as means±S.E.M. **P<0.01, ***P<0.001. (c) Working model summarizing the potential mechanisms of tumor suppression by GABARAP. The subjection of GABARAP KO mice to a genotoxic stress (DMBA) leads to the over and differential expression of the tumor-suppressor gene Xaf1 in non-immune cells, an effect that may trigger cell death events underlying the inhibition of tumor formation. GABARAP-deficient immune cells produce elevated levels of several cytokines under genotoxic stress, which could suppress tumor formation and/or may trigger cell death. Similar mechanisms in the derangement of immune signaling may be involved in growth suppression seen in the GABARAP KO tumor graft model. This prediction requires further investigation in order to clarify the role of GABARAP removal in the reduction of inoculated tumor cell growth
