title: Identification of a New Pathway for Tumor Progression: MicroRNA-181b Up-Regulation and CBX7 Down-Regulation by HMGA1 Protein.
abstract: High mobility group A (HMGA) overexpression plays a critical role in neoplastic transformation. To investigate whether HMGA acts by regulating the expression of microRNAs, we analyzed the microRNA expression profile of human breast adenocarcinoma cells (MCF7) transfected with the HMGA1 gene, which results in a highly malignant phenotype. Among the microRNAs induced by HMGA1, we focused on miR-181b, which was overexpressed in several malignant neoplasias including breast carcinomas. We show that miR-181b regulates CBX7 protein levels, which are down-regulated in cancer, and promotes cell cycle progression. We also demonstrate that CBX7, being negatively regulated by HMGA, is able to negatively regulate miR-181b expression. Finally, there was a direct correlation between HMGA1 and miR-181b expression and an inverse correlation between HMGA1 and CBX7 expression in human breast carcinomas. These data indicate the presence of a novel pathway involving HMGA1, miR-181b, and CBX7, which leads to breast cancer progression.
authors.affiliation: Dipartimento di Biologia e Patologia Cellulare e Molecolare, Istituto di Endocrinologia ed Oncologia Sperimentale del CNR, Università di Napoli "Federico II", Naples, Italy.
authors.forename: Gelsomina
authors.initials: G
authors.lastname: Mansueto
authors.forename: Floriana
authors.initials: F
authors.lastname: Forzati
authors.forename: Angelo
authors.initials: A
authors.lastname: Ferraro
authors.forename: Pierlorenzo
authors.initials: P
authors.lastname: Pallante
authors.forename: Mimma
authors.initials: M
authors.lastname: Bianco
authors.forename: Francesco
authors.initials: F
authors.lastname: Esposito
authors.forename: Antonino
authors.initials: A
authors.lastname: Iaccarino
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Troncone
authors.forename: Alfredo
authors.initials: A
authors.lastname: Fusco