Figure 8
Overexpression of SIRT1 represses lung metastasis. SIRT1 inhibited cancer cell metastasis in vivo in a floor-of-the mouth murine model with SCID mice. Six-week-old male CB17-SCID mice were anesthetized and injected with human OSCC cell line OECM1-S1 (2.5 × 105 cells/mL) stably expressing SIRT1 expression plasmid or vector alone. All surviving mice were sacrificed after 42 days, and orthotopic tumor and lung tissues were removed, fixed, paraffin-embedded, serially sectioned, and subjected to hematoxylin and eosin (H&E) and immunohistochemical (IHC) staining (magnification, ×100). Upper two panels show results of H&E staining and lower two panels show results of Smad4 IHC staining. The lung metastasis index was calculated as follows: metastatic tumor areas/total lung area. T, tumor tissue; M, metastatic nodule. Quantitative metastasis index is indicated as the mean ± SD. The asterisk indicates as statistically significant difference (*, p <0.05) compared to the control.