FIGURE 7.

Blockade of Fas signaling in vivo suppresses tumor growth and metastasis in tumor-bearing mice. 5 × 0⁵ 4T1 tumor cells suspended in 200 μl of Hanks' balanced salt solution were inoculated s.c. into the flank (4th mammary gland) of BALB/c mice; 10 days after tumor inoculation, the cholesterol-conjugated Fas gene siRNA (Fas siRNA) or cholesterol-conjugated negative control siRNA (Ctrl siRNA) (10 nmol of RNA in 0.1 ml of saline buffer) or PBS was intratumorally injected once every 3 days for 2 weeks. Tumor growth (A) and tumor weight from mice 40 days after tumor inoculation (B) were measured as indicated. Data are represented as the mean value ± S.E. from six mice per group. Tumor size was compared at various time points. C, images show representative liver, lung, or DLN metastasis (upper) or metastatic tumor in liver, lung, and DLN via HE staining after 40 days of tumor inoculation (lower). The bar represents 100 μm. The black arrow indicates metastatic tumor. D, top, quantification of the proportion of animals with liver, lung, and DLN micrometastasis. Bottom, contingency table listing the number and percentage of animals in each treatment/metastasis case. *, p < 0.05; **, p < 0.01.