Fig. 6

S100A16 over-expression reduced tumorigenesis in vivo and the resulting tumor xenografts exhibited features of increased differentiation. a One thousand control or S100A16 over-expressing H357 cells were injected in the tongue of each mouse (NOD/SCID) and tumor development was monitored. All mice injected with control cells formed tumors (Tumor Take, TT = 6/6) whereas S100A16-H357 cells formed tumors in 5 of the mice (TT = 5/6). In addition, tumors formed by control cells were significantly larger as compared to that of the S100A16-H357 cells (P = 0.04, at 33 days). Error bars represent SEM. Student’s-t test was performed for statistical analysis. b S100A16-H357 cells took longer time (lag phase) to form tumors as compared to the control cells. Tumor xenografts were harvested, formalin fixed, paraffin embedded and examined for histomorphology, IHC expression of differentiation, proliferation and self-renewal markers. Representative images demonstrating highly differentiated phenotype of S100A16-H357 xenografts with formation of keratin pearls (arrowheads) and higher expression of involucrin (c–f). On the other hand, S100A16-H357 xenografts demonstrated lower expression levels of Ki67 (g and h) and Bmi-1 (i and j) as compared to the control-H357 xenografts. Arrowheads in (g) and (h) mark the invading front. Error bars in (h) represent SEM. Student’s-t test was performed for statistical analysis in (f). +++, strong; ++, moderate; +, weak staining