Discovery of lesser known flavones as inhibitors of NF-κB signaling in MDA-MB-231 breast cancer cells--A SAR study.

Seventeen flavonoids with different substitutions were evaluated for inhibition of nuclear factor-κB (NF-κB) signaling in the invasive breast cancer cell line MDA-MB-231. They were screened using an engineered MDA-MB-231 cell line reporting NF-κB activation. The modulation of expression of two NF-κB regulated genes involved in tumorigenesis, matrix metalloproteinase-9 (MMP-9), and cyclooxygenase-2 (COX-2) were also analyzed in these cells. Among the compounds tested, all except gossypetin and quercetagetin inhibited the activation of NF-κB, and the expression of MMP-9 and COX-2 to different degree. Methylated flavone, chrysoeriol (luteolin-3'-methylether), was found to be the most potent inhibitor of MMP-9 and COX-2 expressions. The effect of chrysoeriol on cell proliferation, cell cycle, apoptosis and metastasis was analyzed by established methods. Chrysoeriol caused cell cycle arrest at G2/M and inhibited migration and invasion of MDA-MB-231 cells. The structure-activity relations amongst the flavonoids as NF-κB signaling inhibitors was studied. The study indicates differences between the actions of various flavonoids on NF-κB activation and on the biological activities of breast cancer cells. Flavones in general, were more active than the corresponding flavonols.

Validation of a human cell based high-throughput genotoxicity assay 'Anthem's Genotoxicity screen' using ECVAM recommended lists of genotoxic and non-genotoxic chemicals.

A novel high throughput-enabled human cell based screen, Anthem's Genotoxicity screen, was developed to achieve higher specificity for predicting in vivo genotoxins by an in vitro method. The assay employs engineered human colon carcinoma cell line; HCT116 cells that are stably engineered with three promoter-reporter cassettes such that an increased reporter activity reflects the activation of associated signaling events in a human cell. The current study focuses on the evaluation of sensitivity and specificity of Anthem's Genotoxicity screen using 62 compounds recommended by the European Centre for the Validation of Alternative Methods (ECVAM). The concordance of Anthem's Genotoxicity screen with in vivo tests was 95.5% with sensitivity of 95.2% and specificity of 95.7%. Thus Anthem's Genotoxicity screen, a high-throughput mechanism based genotox indicator test can be employed by a variety of industries for rapid screening and early detection of potential genotoxins.