Enhanced E2F1 activity increases invasive and proliferative activity of breast cancer cells through non-coding RNA CDKN2B-AS1

Abstract

Long non-coding RNAs have recently appeared as fundamental regulators of gene transcription in several biological processes, but only a few have known functional influences in the malignant transformation of breast cancer. CDKN2B-AS1 gene, also termed ANRIL, encoding a long non-coding RNA is located in the CDKN2B-CDKN2A gene cluster, loss of which is the most frequent alternation in several types of human malignancies. CDKN2B-AS1 is involved in the suppression of tumor suppressor genes (INK4a, ARF, and INK4b) and has been recognized as a direct target of E2F1. However, the roles of E2F1–CDKN2B-AS1 interaction in breast cancer have remained muchly mysterious. In this particular study, we reveal that both CDKN2B and CDKN2B-AS1 genes were differentially expressed in breast cancer cells in contrast to breast epithelial cells. Ectopic expression of E2F1 activated CDKN2B-AS1 but not CDKN2B expression. Lastly, overexpression of E2F1 improved the colony formation and migratory capacities of breast cancer cells. These results suggest that enhanced E2F1 activity increased invasive and proliferative activity of breast cancer but not breast epithelial cells possibly through up-regulating CDKN2B-AS1 transcript.