MicroRNA-221 Targets Bmf in Hepatocellular Carcinoma and Correlates with Tumor Multifocality

• Published in: Clinical cancer research 2009-08, Vol.15 (16), p.5073-5081
• Main Authors: GRAMANTIERI, Laura, FORNARI, Francesca, FERRACIN, Manuela, VERONESE, Angelo, SABBIONI, Silvia, CALIN, George Adrian, LUCA GRAZI, Gian, CROCE, Carlo Maria, BOLONDI, Luigi, NEGRINI, Massimo
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - genetics; Aged; Aged, 80 and over; Antineoplastic agents; apoptosis; Apoptosis - drug effects; Apoptosis - genetics; Biological and medical sciences; Bmf; Carcinoma, Hepatocellular - genetics; Carcinoma, Hepatocellular - mortality; Carcinoma, Hepatocellular - pathology; caspase-3; Female; Gastroenterology. Liver. Pancreas. Abdomen; Gene Expression Regulation, Neoplastic; Gene Targeting; HCC; Humans; Liver Neoplasms - genetics; Liver Neoplasms - mortality; Liver Neoplasms - pathology; Liver. Biliary tract. Portal circulation. Exocrine pancreas; Male; Medical sciences; microRNA; MicroRNAs - antagonists & inhibitors; MicroRNAs - physiology; Middle Aged; Neoplasm Recurrence, Local; Neoplasms, Multiple Primary - genetics; Neoplasms, Multiple Primary - mortality; Neoplasms, Multiple Primary - pathology; Pharmacology. Drug treatments; RNA, Small Interfering - pharmacology; time to recurrence; Tumor Cells, Cultured; Tumors
• ISSN: 1078-0432; 1557-3265
• DOI: 10.1158/1078-0432.CCR-09-0092

Deregulated cell proliferation and apoptosis play a major role in hepatocellular carcinoma (HCC). MicroRNAs participate in the modulation of key molecules linked to hepatocarcinogenesis. Purpose: This study aims to investigate the role of miR-221 in the modulation of Bmf, a proapoptotic BH3-only protein, and to characterize miR-221 contribution to hepatocarcinogenesis through modulation of apoptosis. Experimental Design: Transfection of miR-221 and anti-miR-221 in HCC-derived cell lines and luciferase reporter assay were used to assess Bmf as a target of miR-221. Modulation of miR-221 and Bmf expression contributed to characterize their role in anoikis. Primary HCC tissues were analyzed to assess the clinical relevance of in vitro findings. Results: Enforced miR-221 expression caused Bmf down-regulation, whereas anti-miR-221 induced its up-regulation. A luciferase reporter assay confirmed Bmf as a target of miR-221. Following matrix detachment, miR-221 silencing led to increased apoptotic cell death. The analysis of HCC tissues revealed an inverse correlation between miR-221 and Bmf expression and a direct correlation between Bmf and activated caspase-3, as a marker of apoptosis. High miR-221 levels were associated with tumor multifocality and reduced time to recurrence after surgery. Conclusions: Our results indicate that miR-221, by targeting Bmf, inhibits apoptosis. Moreover, in HCC, miR-221 overexpression is associated with a more aggressive phenotype. These findings, together with the previously reported modulation of CDKN1B/p27 and CDKN1C/p57, show that miR-221 simultaneously affects multiple pro-oncogenic pathways and suggest miR-221 as a potential target for nonconventional treatment against HCC. (Clin Cancer Res 2009;15(16):5073–81)