Kleiner-Hancock et al. BMC Cancer 2010, 10:394 http://www.biomedcentral.com/1471-2407/10/394 Page 4 of 10 Figure 1 ACA and AUR suppress LPS-induced NF- B activation in NF- B-RE-luc (Oslo) mice. Picture depicts live animal imaging of luciferase. with LPS (2.7 mg/kg bw) and imaged 3 h and 24 h after LPS treatment, as described in materials and methods. Mice dosed with LPS expressed a significant increase in NF- B luciferase at 3 h after LPS (Figures 1, 2). Both ACA and AUR significantly inhibited NF- B luciferase expression by 65% and 76%, respectively at 3 h after LPS (Figure 2). There was very little luciferase expres- sion at the pre-screen time point, confirming that the pre-treatments did not activate NF- B. By 24 h, the expression of luciferase declined and there were no sig- nificant differences in any of the treatment groups. ACA and ATRA suppression of skin SCC tumor growth: A potentially beneficial combination Previous data generated by our groups and others sug- gests that ATRA and ACA suppress Stat3 and NF- B activation, respectively [7,22]. As both pathways have been shown to be important in the development of var- ious cancers including skin SCC, we hypothesized that the simultaneous suppression of each pathway using ATRA + ACA would be more effective than using either agent alone at suppressing SCC growth. To address this hypothesis, female SCID/bg mice were inoculated with 1 × 106 SRB12-p9 cells and weighed and their tumors were measure by digital calipers over the course of 25 days. Groups of 5-8 mice each were fed control diets or diets containing ATRA (5, 10, and 30 ppm), ACA (500 ppm), or ATRA + ACA, starting 1 week prior to tumor cell inoculation and for the duration of the study. The dose of ACA was selected based on its activity in pre- vious dietary studies [31-34]. Tumor volume increased Figure 2 Quantitation of luminescence activity in the NF- B study. Figures represent means ± SE (n = 3-4). * Significantly different from control at the same time-point (p ≤ 0.05) (ANOVA followed by Tukey’s test).