Abstract C26: Nuclear factor I/B regulates cell proliferation of ER negative breast cancer

Abstract

Previously, we reported that DNA copy number of NFIB is amplified in triple negative breast cancer (TNBC; estrogen(−)/progesterone(−)/HER2(−)). The transcriptional activator NFIB plays wide roles in regulation of gene transcription, cell proliferation, viral DNA replication and development. But the functional role of NFIB in breast cancer cell has not been elucidated. In order to understand the role of upregulated NFIB in breast cancers, we examined mRNA and protein level of NFIB in 20 breast cancer tissues. In ER negative breast cancer subtype, expression of NFIB is up-regulated and correlated with Ki67 expression. And intracellular localization of NFIB is restricted in nucleus. In ER negative cell line, knock-down of NFIB leads to reduced cell proliferation by cell cycle arrest. Cell cycle arrest is accompanied by S phase arrest and alteration of S phase regulating protein expression. Take together, transcription activator of NFIB regulates cancer cell proliferation in ER negative breast cancer and it may act as a therapeutic marker. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C26.