(A) One of our main research goals is the identification and characterization of microRNAs (miRNAs) involved in tumor progression, referring in particular to breast cancer and melanoma. Human tumor samples or metastases derived from patients that relapsed or not and differentially malignant tumor cell lines are used to evaluate miRNA expression by performing microarray and qRT-PCR analyses. In this way it is possible to identify signatures that can be used to classify tumors and predict the outcome of the deseases. The predictive miRNAs are then overexpressed or silenced in cell lines and their biological function is evaluated in terms of proliferation, apoptosis, tumor formation and in particular migration/invasion and metastasis dissemination by performing in vitro (cell culture) and in vivo (mouse) experiments. Since miRNAs regulate protein-coding gene expression it is essential to identify the miRNA target genes responsible of certain biological funcitons. For this purpose we are using protein-coding gene expression profiles and computational predictions with several algorithms. The targets are validated using luciferase reporter vectors containing 3’UTR sequences of the potential target genes and by western blot analyses. We are planning to generate trangenic and knock out mouse models for one or more identified miRNAs and use miRNAs as targets for gene therapy in tumors.
Example of results:
Fig. 1-Breast cancer
Fig. 2-Melanoma
(B) Another line of research going on in our laboratory regards the role of the AP-2 transcription factors and its gene targets in adenocarcinoma progression. A role for AP-2 in cancer is suggested by many evidences. First, AP-2 is lost in metastatic melanomas, where it acts as a tumor suppressor gene; second, AP-2 proteins are essential regulators of a number of genes central to cancer, e.g. ERBB2, E-cadherin, VEGF, p21WAF/CIP and others; third, AP-2 interact with p53 and myc proteins at different promoters. The AP-2 family consists of five members that can form homo- or heterodimers and transactivate many target genes by binding to GC-rich consensus sequences present in their promoter regions and orchestrate a variety of cell processes including apoptosis, cell growth, cell adhesion and tissue differentiation. We recently overexpressed and silenced (RNAi) two AP-2 family members, AP-2alpha and/or AP-2gamma in various adenocarcinoma cell lines and observed that both AP-2 members act as tumor suppressors during the first steps of tumorigenesis, in fact in absence of AP-2 cells grow faster in soft agar models or when injected in immunodeficient mice (xenotransplants). However AP-2 silencing reduces cell motility and invasion. By performing microarray analysis we identified some players that modulate cell motility or invasion such as ESDN, EREG and CXCL2. We are now characterizing those players and their transcriptional regulation by AP-2.
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Friard O, Re A, Taverna D, De Bortoli M and Cora' M. CircuitsDB: a database of mixed microRNA / Transcription. BMC Bioinformatics, 2010, 11:435-445.
Dentelli P, Rosso A, Orso F, Taverna D and Maria Brizzi MF. miR-222 controls neovascularization by regulating STAT5A expression. Arteriosclerosis, Thrombosis and Vascular Biology, 2010, 30:1562-1568
Orso F, Corà D, Ubezio B, De Bortoli M, Provero P, M. Caselle and Taverna D. Analysis of the regulatatory regions of AP-2amodulated genes. BMC Genomics, 2010, 11: 355.
Cabodi S. and Taverna D. Interfering with inflammation: a new strategy to block breast cancer self-renewal and progression? Breast Cancer Research, 2010, 12:305.
Thewes V, Orso F, Jäger R, Eckert D, Kirfel G, Garbe G, Taverna D and Schorle H. Interference with Activator Protein-2 transcription factors leads to induction of apoptosis and an increase in chemo- and radiation- sensitivity in breast cancer cells. BMC Cancer, 2010, 10:192
Orso F, Jaeger R, Calogero RA, Schorle H, Sismondi P, De Bortoli M and Taverna D. AP-2ALPHA REGULATES MIGRATION OF GN-11 NEURONS VIA A SPECIFIC GENETIC PROGRAM INVOLVING THE AXL RECEPTOR TYROSINE KINASE. BMC Biology, 2009, 7:25.
Re A, Corà D, Taverna D and Caselle M. GENOME WIDE SURVEY OF MICRO RNA-TRANSCRIPTION FACTOR REGULATORY CIRCUITS IN HUMAN. Mol. BioSyst., 2009, 5: 854-867.
Dentelli P, Trombetta A, Togliatto G, Zeoli A, Rosso A, Uberti B, Orso F, Taverna D, Pegoraro L, Brizzi MF. FORMATION OF STAT5/PPAR{GAMMA} TRANSCRIPTIONAL COMPLEX MODULATES ANGIOGENIC CELL BIOAVAILABILITY IN DIABETES. Arterioscler Thromb Vasc Biol., 2009 Jan;29(1):114-20.
Cimino D, Fuso L, Sfiligoi C, Biglia N, Ponzone R, Maggiorotto F, Russo G, Cicatiello L, Weisz A, Taverna D, Sismondi P, De Bortoli M. IDENTIFICATION OF NEW GENES ASSOCIATED WITH BREAST CANCER PROGRESSION BY GENE EXPRESSION ANALYSIS OF PREDEFINED SETS OF NEOPLASTIC TISSUES. Int J Cancer. 2008 Sep 15;123(6):1327-38.
Orso F, Penna E, Cimino D, Astanina E, Maione F, Valdembri D, Giraudo E, Serini G, Sismondi P, De Bortoli M, Taverna D. AP-2ALPHA AND AP-2GAMMA REGULATE TUMOR PROGRESSION VIA SPECIFIC GENETIC PROGRAMS. FASEB J. 2008 Aug;22(8):2702-14. Epub 2008 Apr 28.
Orso F, Fassetta M, Penna E, Solero A, De Filippo K, Sismondi P, De Bortoli M, Taverna D. THE AP-2ALPHA TRANSCRIPTION FACTOR REGULATES TUMOR CELL MIGRATION AND APOPTOSIS. Adv Exp Med Biol. 2007;604:87-95.
Taverna D, Crowley D, Connolly M, Bronson RO and Richard Hynes. (2005). A DIRECT TEST OF POTENTIAL ROLES FOR BETA3 AND BETA5 INTEGRINS IN GROWTH AND METASTASIS OF MURINE MAMMARY CARCINOMAS. Cancer Res. Nov 15; 65(22):10324-9.
Taverna D, Moher H, Crowley D, Borsig L, Varki A, Hynes RO. (2004). INCREASED PRIMARY TUMOR GROWTH IN MICE NULL FOR BETA3- OR BETA3/BETA5-INTEGRINS OR SELECTINS. Proc Natl Acad Sci U S A. 2004 Jan 20;101(3):763-8.
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