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Bellissimo T, Ganci F, Gallo E, Sacconi A, Tito C, De Angelis L, Pulito C, Masciarelli S, Diso D, Anile M, Petrozza V, Giangaspero F, Pescarmona E, Facciolo F, Venuta F, Marino M, Blandino G, Fazi F. Thymic Epithelial Tumors phenotype relies on miR-145-5p epigenetic regulation. Mol Cancer 2017; 16:88. [PMID: 28486946 PMCID: PMC5424390 DOI: 10.1186/s12943-017-0655-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 04/24/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Thymoma and thymic carcinoma are the most frequent subtypes of thymic epithelial tumors (TETs). A relevant advance in TET management could derive from a deeper molecular characterization of these neoplasms. We previously identified a set of microRNA (miRNAs) differentially expressed in TETs and normal thymic tissues and among the most significantly deregulated we described the down-regulation of miR-145-5p in TET. Here we describe the mRNAs diversely regulated in TETs and analyze the correlation between these and the miRNAs previously identified, focusing in particular on miR-145-5p. Then, we examine the functional role of miR-145-5p in TETs and its epigenetic transcriptional regulation. METHODS mRNAs expression profiling of a cohort of fresh frozen TETs and normal tissues was performed by microarray analysis. MiR-145-5p role in TETs was evaluated in vitro, modulating its expression in a Thymic Carcinoma (TC1889) cell line. Epigenetic transcriptional regulation of miR-145-5p was examined by treating the TC1889 cell line with the HDAC inhibitor Valproic Acid (VPA). RESULTS Starting from the identification of a 69-gene signature of miR-145-5p putative target mRNAs, whose expression was inversely correlated to that of miR-145-5p, we followed the expression of some of them in vitro upon overexpression of miR-145-5p; we observed that this resulted in the down-regulation of the target genes, impacting on TETs cancerous phenotype. We also found that VPA treatment of TC1889 cells led to miR-145-5p up-regulation and concomitant down-regulation of miR-145-5p target genes and exhibited antitumor effects, as indicated by the induction of cell cycle arrest and by the reduction of cell viability, colony forming ability and migration capability. The importance of miR-145-5p up-regulation mediated by VPA is evidenced by the fact that hampering miR-145-5p activity by a LNA inhibitor reduced the impact of VPA treatment on cell viability and colony forming ability of TET cells. Finally, we observed that VPA was also able to enhance the response of TET cells to cisplatin and erlotinib. CONCLUSIONS Altogether our results suggest that the epigenetic regulation of miR-145-5p expression, as well as the modulation of its functional targets, could be relevant players in tumor progression and treatment response in TETs.
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Affiliation(s)
- Teresa Bellissimo
- Deptartment of Anatomical, Histological, Forensic & Orthopaedic Sciences, Section of Histology & Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - Federica Ganci
- Oncogenomic and Epigenetic Unit, "Regina Elena" National Cancer Institute, Rome, Italy
| | - Enzo Gallo
- Department of Pathology, "Regina Elena" National Cancer Institute, Rome, Italy
| | - Andrea Sacconi
- Oncogenomic and Epigenetic Unit, "Regina Elena" National Cancer Institute, Rome, Italy
| | - Claudia Tito
- Deptartment of Anatomical, Histological, Forensic & Orthopaedic Sciences, Section of Histology & Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - Luciana De Angelis
- Deptartment of Anatomical, Histological, Forensic & Orthopaedic Sciences, Section of Histology & Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - Claudio Pulito
- Molecular Chemoprevention Unit, "Regina Elena" National Cancer Institute, Rome, Italy
| | - Silvia Masciarelli
- Deptartment of Anatomical, Histological, Forensic & Orthopaedic Sciences, Section of Histology & Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - Daniele Diso
- Department of Thoracic Surgery, Azienda Policlinico Umberto I, Sapienza University of Rome, Rome, Italy.,Fondazione Eleonora Lorillard Spencer Cenci, Rome, Italy
| | - Marco Anile
- Department of Thoracic Surgery, Azienda Policlinico Umberto I, Sapienza University of Rome, Rome, Italy.,Fondazione Eleonora Lorillard Spencer Cenci, Rome, Italy
| | - Vincenzo Petrozza
- Pathology Unit, ICOT, Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Latina, Italy
| | - Felice Giangaspero
- Department of Radiological, Oncological, and Anatomo-pathological Science, Sapienza University of Rome, Rome, Italy and IRCCS Neuromed, Pozzilli, Italy
| | - Edoardo Pescarmona
- Department of Pathology, "Regina Elena" National Cancer Institute, Rome, Italy
| | - Francesco Facciolo
- Thoracic Surgery Unit, "Regina Elena" National Cancer Institute, Rome, Italy
| | - Federico Venuta
- Department of Thoracic Surgery, Azienda Policlinico Umberto I, Sapienza University of Rome, Rome, Italy.,Fondazione Eleonora Lorillard Spencer Cenci, Rome, Italy
| | - Mirella Marino
- Department of Pathology, "Regina Elena" National Cancer Institute, Rome, Italy
| | - Giovanni Blandino
- Oncogenomic and Epigenetic Unit, "Regina Elena" National Cancer Institute, Rome, Italy.
| | - Francesco Fazi
- Deptartment of Anatomical, Histological, Forensic & Orthopaedic Sciences, Section of Histology & Medical Embryology, Sapienza University of Rome, Rome, Italy.
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