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MO04 - Lung Cancer Biology I (ID 86)
- Event: WCLC 2013
- Type: Mini Oral Abstract Session
- Track: Biology
- Presentations: 1
MO04.08 - Activation of liver X receptor induces interferon-gamma production and inhibits tumor growth (ID 705)
16:15 - 17:45 | Author(s): Q. Wang
Interferon-γ (IFN-γ) has been well documented to have multiple functions including anti-tumorigenesis. Liver X receptors α and β (LXR) are members of ligand- activated nuclear receptor superfamily. LXR can be ac- tivated by natural ligands of some oxysterols and by numerous synthetic ligands (e.g. T317).The LXR-induced ABCA1 expression promotes free cholesterol efflux from macrophages thereby inhibiting the development of atherosclerosis. LXR has also been demonstrated the important functions in immune system . Here we tested the hypothesis that IFN-γ is a target for LXR activation, and the induction of IFN-γ expression by LXR can lead to inhibition of tumor growth.
C57 wild type or IFN-γ-/- mice (same background) in two groups were s.c. injected with2×10 5 LLC1 cells (ATCC) in the right ﬂank to establish a carcinoma tumor model. For carcinogen-induced tumor: at the ﬁrst week, C57 mice were i.p. injected with MCA (15 mg/kg body); from the second week, the mice were i.p. weekly injected with BHT for 6 weeks. The doses of BHT were: 1st injection, 150 mg/kg body weight; 2nd to 6th injections, 200 mg/kg.
In this study, we observed that LXR ligand (T317) induced IFN-γ protein expression which was associated with increased mRNA and secreted protein levels in culture medium. In vivo,T317 increased wild type mouse serum IFN-γ levels and IFN-γexpression in tissues. T317 inhibited the inoculated LLC1 tumor growth in wild type mice but not in IFN-γ knockout (IFN-γ-/-) mice. In addition, T317 displayed inhibitory and therapeutic effects on 3-methylcholanthrene/butylated hydroxytoluene (MCA/BHT)-induced pulmonary carcinomas. T317 inhibits the growth of inoculated LLC1 tumor in wild type mice but not in IFN-γ-/- mice Wild type or IFN-γ-/- mice. Figure 1 T1317 inhibits MCA/BHT-induced pulmonary tumors Figure 2
Our study demonstrates IFN-γ is a target gene of LXR activation. LXR-induced IFN-γ expression can be attributed, at least in part, to the anti-tumorigenic properties of LXR.
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